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Bytes of Science: March 2006

Bytes of Science: March 2006

Error: 1 Sensors 2013, 13, ; doi: /s Review OPEN ACCESS sensors ISSN A Flexible Sensor Technology for the Distributed Measurement of Interaction Pressure Marco Donati 1, *, Nicola Vitiello 1, Stefano Marco Maria De Rossi 1, Tommaso Lenzi 1, Simona Crea 1, Alessandro Persichetti 1, Francesco Giovacchini 1, Bram Koopman 2, Janez Podobnik 3, Marko Munih 3 and Maria Chiara Carrozza The BioRobotics Institute, Scuola Superiore Sant Anna, viale Rinaldo Piaggio 34, Pontedera (PI), Italy; s: (N.V.); (S.M.M.D.R.); (T.L.); (S.C.); (A.P.); (F.G.); (M.C.C.) Biomechanical Engineering Laboratory, Institute for Biomedical Technology and Technical Medicine (MIRA), University of Twente, 7500 EA Enschede, The Netherlands; Laboratory of Robotics, University of Ljubljana, SI-1000 Ljubljana, Slovenia; s: (J.P.); (M.M.) * Author to whom correspondence should be addressed; Tel.: ; Fax: Received: 1 November 2012; in revised form: 8 January 2013 / Accepted: 8 January 2013 / Published: 15 January 2013 Abstract: We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is completely modular and scalable, allowing one to cover areas of any sizes and shapes, and to measure different pressure ranges. In this work we present the main application areas for this technology. A first generation of the system was used to monitor human-robot interaction in upper- (NEUROExos; Scuola Superiore Sant Anna) and lower-limb (LOPES; University of Twente) exoskeletons for rehabilitation. A second generation, with increased resolution and wireless connection, was used to develop a pressure-sensitive foot insole and an improved human-robot interaction measurement systems. The experimental characterization of the latter system along with its validation on three healthy subjects is presented here for the first time. A perspective on future uses and development of the technology is finally drafted.2 Sensors 2013, Keywords: distributed force sensor; wearable robotics; physical human-robot interaction; pressure-sensitive insole 1. Introduction In the last decade, human-centered robotics has seen huge developments in academic and industrial research, bringing to the market more and more robots able to cooperate safely with humans. Technological advancements and an increased interest by the medical community led to the development of service and domestic robots [1], medical robots for surgical aid [2] and rehabilitation [3 5], and wearable robots [6]. Wearable robots have been seen as a promising solution in many fields, including rehabilitation [4], functional replacement for disabled [7 11], walking assistance for the elderly [12] and load-carrying augmentation for soldiers [13]. A wearable robot, or exoskeleton, is an active robotic device that can be worn by the user. Links and joints of the exoskeleton are placed in correspondence of those of the human body, and are connected to the limbs in multiple points. These robots interact closely with the body and are supposed to cooperate actively with the user [12 17]. A distinctive characteristic of exoskeletons compared to other haptic robots is their closer physical and cognitive coupling with the user [17]. The mechanics and control that allow this physical and cognitive cooperation constitute the human-robot interface. In this work, we are interested to the physical human-robot interfaces, i.e., the mechanical and sensor components that mediate the transfer of power between the user and the exoskeleton [18]. There are two main ways to connect wearable robots with the user: connection cuffs and orthoses. Connection cuffs are rigid links supporting a soft belt of adjustable size that is fastened around the user s limb. This solution has been used in both lower- [4,19] and upper-limb [20,21] exoskeletons. Orthoses, on the other hand, are shells made of plastic or other orthopaedic materials, potentially tailored on the user s limb, which are connected with the link of the robot. Orthotic shells, which have been also used in upper- and lower-limb devices [21 29], have the advantage of distributing the interaction evenly on a wide skin area, increasing the comfort and reducing the pain. In both cases, getting an accurate measurement of the physical interaction is critical, as explained in [18] and [30 32], not only for control purposes, but also to assess the reaction of the user to the assistance given by the robot. Interaction force can be measured in two ways [33,34]: (i) by estimating the interaction torque through the measurement of the robot joint torque, as in the LOPES [19]; or (ii) directly measuring the force between exoskeleton and limb using load cells or similar technologies [32]. Both approaches have limitations. In the first method, the physical human-robot interaction (phri) force estimate can be corrupted by an inaccurate model of human-robot dynamics. In alternative to this, direct force measurements, while very accurate, have several drawbacks, i.e., a multiple-degree-of-freedom exoskeleton would require as many localized force sensors as the number of contact points, leading to increased costs and complexity [33]; in addition, single-point measures such as those from a load cell hide all information related to the distribution of pressures at the cuff/orthosis: this can be extremely useful, being directly related with the safety and comfort felt by the user during the robot operation (high pressures might be uncomfortable or even painful to the3 Sensors 2013, user [35,36]); finally, single-point measures do not provide information about the preloading force when straps are used to fasten the limb to the device [33,37]. Based on the above considerations, over the last four years we developed a sensor technology for the measurement of distributed pressures, that we call Pressure Sensor Pads (PSP). We applied our technology on connection cuffs [34,37] of the lower-limb exoskeleton LOPES, and orthotic shells of NEUROExos [33], a powered elbow exoskeleton for physical rehabilitation [24,38]. Results from experimental activities showed that PSPs have good performances in terms of accurateness, sensitivity, dynamics behaviour and compliance with the mechanical requirements of the test platforms. This technology is based on an opto-electronic transduction principle, is completely modular and scalable, and allows to monitor pressures over areas of any sizes and shapes. This feature, along with the possibility to vary the pressure range given the specific application, makes our technology ideal to measure interaction forces in wearable robots. A further development of this technology was used to build a pressure-sensitive insole [39]. In this paper we survey the technology and its applications. Section 2 overviews the prototypes of the first (PSP1) and second (PSP2) generation of Pressure Sensor Pads, and introduces a novel PSP2 prototype for cuffs and orthoses-based on the same technology we developed for foot pressure monitoring. In Section 3, we give extended experimental results of our sensors applied to upper- and lower-limb exoskeletons. Section 3 also presents unpublished results obtained from the experimental validation of the new PSP2 prototype with the LOPES exoskeleton. Section 4 draws some conclusions and drafts a perspective on future uses and development of the technology. 2. Pressure-Sensor Technology In this section we present the evolution of the design of the sensor, along with their mechanical and electrical characterization Design of the First Generation: PSP1.0 and PSP1.1 The first generation of the pressure-sensor technology is loosely based on the Skilsens technology, a tactile technology conceived in our laboratory eight years ago [40,41]. The sensor is an optoelectronic pressure sensor made of two main parts: an external silicone bulk structure, and a printed circuit board (PCB) which houses an array of sensitive elements. The dimension of the sensor can be adjusted based on the constraints given by the specific application. In this example, the size is mm which allows to house an array of 1 8 sensitive elements. The technology can be applied to custom sizes and number of sensors. Each sensitive element is composed of a light transmitter, a LED (an InGaN chip technology, high luminosity green LED, OSA Opto Light GmbH, Berlin, Germany) and a receiver, a photodiode (an og ambient light opto-electronics transducer with current output, Avago Technologies Ltd., Singapore). The silicone bulk covers the electronics components and plays an active role in the transduction principle: when a load is applied on the sensor, the cover deforms itself, the light is screened and the sensor changes proportionally its output voltage (see Figure 1).4 Sensors 2013, Figure 1. Overview of the PSP1: (a) specific scheme of the 1 8 array of sensitive elements of the PSP 1.0 and PSP1.1; (b) scheme of the transduction principle; (c) 3D design of the PSP1.1 (adapted from [37]). By varying the silicone material and the thickness of the cover, the structural rigidity of the sensor can be changed. Two different covers were developed for two different applications (see Section 3). The first cover (named PSP1.0) has a bulk made of two different rubbers, an extern black silicone (ECOFLEX, Shore 00-30, Smooth-On Inc., Easton, PA, USA) and an internal transparent and less stiff silicone (ECOFLEX, Shore 00-15, Smooth-On Inc.). The total thickness of the pad is 8 mm [33]. Only the external silicone obstructs the light path and induces a change of the sensor s output. The second cover (named PSP1.1) has only a single silicone shell (Sorta Clear 40, Shore 40 A, Smooth-On Inc.) coloured with black pigment, for a total thickness of the sensor of 7 mm [37] (see Figure 1). The silicone Sorta Clear 40 was characterized by Axel Products Inc. (Ann Arbor, MI, USA) to define their basic elastomeric properties through the execution of four mechanical tests [42,43]: simple tension (using a long and thin specimen and a laser extensometer), pure shear (using a wide specimen and a laser extensometer), equal biaxial stress (using a circular specimen stretched on radial direction, and a laser extensometer), and volumetric compression (using a cylindrical specimen). All of the tests were performed under slow cyclical loads to avoid the Mullin effect (changing structural properties during the first loading cycle). Data of characterization were used to create a nine-parameter Mooney-Rivlin solid model, necessary to develop a 3-dimensional finite-element (3D FE) model of the silicone cover in ANSYS 12 (Ansys Inc., Canonsburg, PA, USA). It is possible to vary the sensing range of the sensor by changing some design parameters. In the case of PSP1.0, force range can be adjusted by changing the thickness of the internal silicone layer. In the case of PSP1.1 the desired force range can be changed by adjusting the five geometrical parameters that characterize the section of the silicone cover: (i) the internal height Hi, (ii) upper-part thickness T, (iii) the basis thickness W, (iv) and (v) the internal and external radii which connect the basis to the upper part, Ri and Re (see Figure 2). While the design of PSP1.0 resulted from an heuristic experimental process, the silicon cover of PSP1.1 was designed thanks to a 3D FE ysis by using ANSYS 12. Given a desired sensitive range of 60 N at a deformation of about 1.5 mm, which leads to saturation of the sensor s output, many simulations were carried out with different sets of geometrical parameters Hi, T, W, Ri and Re.5 Sensors 2013, Figure 2. Cross section of the PSP1.1 (adapted from [37]). In each simulation a rigid flat indenter pushed on the sensor (see Figure 3) with an increasing load onto the top face of the sensor (Figure 3). The contact region was modelled as a rigid friction connection; this choice was based on the difficulty to model the friction on hyper-elastic material [44]. On the other hand, the contact area between the silicone bulk and the PCB was modelled as fixed support. We simulated the load by imposing a displacement of the indenter with respect to the PCB, and for each deformation state we evaluated the total stress state, the deformation state and the total force response of the structure. The FE ysis shows that the structure suffers of a sinking effect, which increases the light occlusion for small loads. Although it would increase the sensitivity of the sensor for low forces, at the same time, it would also lead to a reduction of the sensing range: smaller load would cause the silicone cover to touch the PCB and, as a consequence, the sensor to saturate. Figure 3. Finite element simulation of PSP1.1: (a) un-deformed structure; the rigid flat indenter is transparent brown, the silicone structure is grey and the PCB is green; (b) total deformation representation; (c) total stress representation (adapted from [37]). The geometrical parameters leading to a desired interaction force of 60 N, corresponding to an average pressure on the pad of 50 kpa (a desired force range chosen based on a series of preliminary experiments [34]), are: Hi = 4 mm, T = 3 mm, W = 3 mm, Ri = 6 mm and Re = 6 mm. By using these parameters, the silicone cover was obtained by casting liquid silicone in a male/female acrylic mold. After the polymerization the silicone cover was glued on the PCB Experimental Characterization of PSP1.0 and PSP1.1 For both PSP1.0 and PSP1.1 an experimental characterization was carried out to find their structural (force/deformation) and opto-electrical (sensor s output/force) behaviour [33,37]. Both characterizations were obtained by means of a similar procedure, i.e., by applying a load on the sensor using a rigid flat indenter, like in the FE simulations, while recording sensor deformation and output voltage. The characterizations were performed using an INSTRON 4464 testing machine (INSTRON Inc., Norwood, MA, USA), equipped with a 1 kn load cell. For each sensor five loading-unloading6 Sensors 2013, cycles were performed at a relatively low speed (0.1 mm/min for PSP1.0, and 1 mm/min for PSP1.1), to simulate a quasi-static load. In order to know the specific response of the sensor to the applied load, we characterized the voltage output of the sensor against the applied load. For each sensor output, experimental data were fitted with a second-order polynomial function to obtain a model of the sensor. Figure 4 shows the output voltage vs. applied force behaviour of each couple of light emitter-receiver of the 1 8 array of sensitive elements of both PSP1.0 and PSP1.1. A summary of the main technical characteristics of the sensors are reported in the Table 1. Table 1 shows that the maximum loading force on the surface (equal to 12 cm 2 ) of PSP1.1 is greater than the one of PSP1.0, whereas the maximum deformation is comparable, and the maximum hysteresis slightly decreases. The latter difference is mainly due to the absence in PSP1.1 of the viscous internal layer of transparent silicone. Despite a different force range, PSP1.0 and PSP1.1 have a comparable force vs. output voltage behaviour: voltage-to-force curves increase monotonically and have small hysteresis compared to the full-scale range. Figure 4. Force (or pressure) vs. output voltage of the PSP1 1 8 array of sensitive elements: (a) PSP1.0; (b) PSP1.1 (adapted from [33,37]. (a) is a slightly adapted reprinted graphics from [33], 2011, with permission from Elsevier). (a)7 Sensors 2013, Figure 4. Cont. (b) Table 1. Main features of the PSP1 prototypes: maximum loading force, maximum pressure, maximum deformation, average stiffness, and maximum hysteresis expressed in percentage of the full-scale range of the input (values are extracted from [33,37]). PSP1.0 PSP1.1 Maximum loading force 10 N 60 N Maximum pressure on the surface 8.3 kpa 50 kpa Maximum deformation 1.9 mm 1.5 mm Average stiffness 5.26 N/mm 40 N/mm Hysteresis 3.8% 3% 2.3. Design of the Second Generation: PSP2.0 and PSP2.1 The transduction principle of the second generation (PSP2) is conceptually ogous to the principle described for the first generation. The main differences are: (i) the structure of the sensor, which is composed by independent silicone cells, one for each couple of light emitter-receiver, and (ii) the shape of the silicone cover. Thus, each sensitive element is composed of two main parts: the silicone cover and a PCB (which can be either flexible or rigid) that houses the sensitive component. The sensitive element is composed of the light emitter, a high luminosity green LED (an InGaN chip technology, high luminosity green LED, OSA Opto Light GmbH), and the light receiver, a photodiode (an og ambient light opto-electronics transducer with current output, Avago Technologies Ltd.). The LED faces the near receiver. The cover is realized with a silicone shell coloured by a black ink, and has the shape of a pyramidal frustum with a square basis, with an internal central curtain (see Figure 5). The dimension of the frustum base is mm 2, while the top face is mm 2, and the height is 5.5 mm. Figure 5(b) points out the transduction principle: when a load is applied onto the frustum top face, the8 Sensors 2013, silicone bulk deforms itself, the curtain within the cover closes the light way, and the sensor varies its output voltage [45,46]. This contact surface provides a 1 cm 2 resolution to the estimation of pressure distribution. Figure 5. Overview of the second-generation PSP sensitive element: (a) dimension of the sensitive element, (b) transduction principle (adapted from [39], 2011 IEEE. Reprinted with permission). Figure 6 shows a cross section of the PSP2 silicone cover. The shape of the cover is identified by five geometrical parameters: (i) thickness T, (ii) the height of the curtain H1, (iii) the height of the pyramidal frustum H2, (iv) the side of the base B1, (v) the side of the top-face base B2. The value of these parameters and the material have to be chosen in order to obtain a shell sensible to the load applied. Figure 6. Cross section of the PSP2 silicone cover; the geometrical parameters are: cover thickness T, height of the curtain H1, pyramidal frustum height H2, square base size B1, square top-face size B2. For the second generation we realized two different silicon covers, for two different prototypes: PSP2.0 and PSP2.1, made with different silicones and having two different sets of geometrical parameters. For PSP2.0 we used Dragon Skin 10 Medium (Smooth-On Inc., Shore 10 A), whereas for PSP2.1 we used the stiffer Sorta Clear 40 (Smooth-On Inc., Shore 40 A). Similarly to the silicone used for the cover of PSP1.1, the Dragon Skin 10 was characterized by the Axel Products Inc., to define its basic elastomeric properties [42,43], and data were used to define the nine-parameter Mooney-Rivlin solid model to create the 3D FE model in ANSYS 12.9 Sensors 2013, Figure 7. 3D FE simulations of PSP2.1: (a) simulation environment: in blue the rigid indenter, in grey the silicone structure, in green the PCB; (b) map of the total deformation, (c) cross-section of the pyramidal frustum showing the sinking effect. Similarly to PSP1.1, PSP2 geometrical parameters were identified by iterative simulations in which a rigid flat indenter parallel to the PCB applied an increasing load onto the top-face of the pyramidal frustum (see Figure 7). The final choice of the geometrical parameters was determined by the need of minimizing the sinking effect of the top face (see Figure 7(c)). Geometrical parameters were finally selected to address the requirements of two different applications. For PSP2.0, geometrical parameters were selected with the objective to develop an insole made of an array of sensors to measure the foot-ground interaction pressure during gait. The pressure range of the sensitive element was set to kpa. This pressure range ensures to measure, without saturations, the vertical ground reaction force (vgrf) during gait of a standard man (about 70 kg), walking at a normal speed (up to 1.3 m/s). A typical vertical force pattern shows, in fact, that the value of the peak occurring in response to the weight accepting event, is approximately the 130% of the body weight [47], that is here considered to be applied in one third of the sensitive area. The geometrical parameters of PSP2.0 are: T = 3 mm, H1 = 2.3 mm, H2 = 5.5 mm, B1 = 12 mm, B2 = 10 mm. On the other hand, PSP2.1 silicone pyramidal frustum was designed with the final aim of developing an array to monitor the interaction force at a cuff of the lower-limb exoskeleton LOPES, and therefore the sensing range was set to 3.5 N. This value corresponds to a maximum pressure of about 35 kpa, which is comparable with the pressure range explored in [37]. The geometrical parameters of PSP2.1 are: T = 1.5 mm, H1 = 2.9 mm, H2 = 5.5 mm, B1 = 12 mm, B2 = 9 mm. Similarly to PSP1, PSP2 silicone covers were obtained by casting liquid silicone in acrylic molds. After polymerization, silicone covers were glued onto the PCB Characterization of the Second Generation As for the first generation, the experimental characterization aimed at assessing the force vs. deformation behaviour of the silicone cover, as well as at constructing the force- (or pressure)-tooutput voltage curve of each sensor. The force-to-output voltage characterization of PSP2.0 and PSP2.1 was performed by using a 3-axial platform (TAP) machine, developed at The BioRobotics Institute of Scuola Superiore Sant'Anna (Pisa, Italy), equipped with a six-axis load-cell (ATI Nano-17 SI , ATI Industrial Automation, Apex, NC, USA), and a rigid flat indenter. While applying the deformation on the sensitive element (setting a maximum deformation of 1.2 mm), we recorded the reaction force and the output voltage of each sensor.10 Sensors 2013, For PSP2.0 we performed a quasi-static force vs. deformation characterization, executing three loading-unloading cycles with a loading speed of mm/s (i.e., ~5 mm/min). All data were off-line low-pass filtered with a third-order Butterworth filter, with cut-off frequency equal to 100 Hz (Matlab filtfilt function). Force-to-output voltage loading-unloading cycles were fitted by a third-order polynomial function which was found to be the best compromise in terms of complexity and goodness of fit, with root mean square error (RMSE) equal to N. The maximum load generates a vertical deformation of about 1.8 mm (see Figure 8(a)). The non-amplified output voltage of the sensor has a dynamic range of about 1.1 V, corresponding to a 50 N load on the sensor (see Figure 8(b)) [39]. Figure 8. Characterization of the sensitive element of PSP2.0: (a) quasi-static force-to-deformation characterization; (b) quasi-static force-to-voltage curve (adapted from [39], 2011 IEEE. Reprinted, with permission). (a) (b) For PSP2.1 we executed three loading-unloading cycles with a loading speed of 0.1 mm/s to get a quasi-static force vs. deformation characterization. Then, in order to assess the mechanical hysteresis we also performed loading-unloading cycles at seven increasing levels of loading speed, i.e., from 0.05 mm/s to 1 mm/s (three cycles for each speed). All data were off-line low-pass filtered with a third-order Butterworth filter, with a cut-off frequency equal to 30 Hz (Matlab filtfilt function). Data reported in Figure 9(a) shows that the silicone cover has a non-linear force-to-deformation behaviour in quasi-static condition, with a slight hysteresis of 0.16 N, i.e., 5% of the full-scale range. All force-to-deformation loading-unloading cycles were fitted by a fourth-order polynomial function. In Table 2 we report the RMSE and the R 2 of the fitting, as well as the loading-unloading hysteresis. Finally, Figure 9(b) reports the fitting curves for all loading speeds. The force-to-output voltage characterization of the sensor is reported in Figure 9(c). The output voltage has a monotonic rising trend, and ranges from 0 to 0.85 V. Quasi static force-to-voltage curve is well fitted by a smoothing spline (Matlab cftool), with RMSE = N. Table 2. RMSE, R 2 and maximum hysteresis for force-to-deformation characterization of PSP2.1. Quasi-static 0.05 mm/s 0.1 mm/s 0.2 mm/s 0.3 mm/s 0.4 mm/s 0.5 mm/s 1 mm/s RMSE R Hysteresis 5.75% 6.31% 6.36% 6.30% 7.56% 8.41% 8.87% 11.43%11 Sensors 2013, Figure 9. Results of the PSP2.1 characterization: (a) quasi-static force-to-deformation loading-unloading, averaged over three iterations (black line is the loading phase, grey line is the unloading phase); (b) all fitting curves of loading-unloading cycles at seven different levels of loading speed (namely, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1 mm/s); (c) quasi-static force-to-voltage curve (blue dots are experimental data, black line is the smoothing spline). 3. Applications (a) (b) (c) This section provides an overview of the scenarios in which the PSPs (of both first and second generations) were tested. Firstly, we will report the results from the test of PSP1.0 with the exoskeleton of upper-limb NEUROExos and from the test of the PSP1.1 with the cuffs of the lower-limb LOPES exoskeleton. Secondly, we will show the results of the application of the PSP2.0 and PSP2.1 respectively for the construction of a pressure-sensitive insole and a novel prototype of sensorized cuff of the LOPES exoskeleton. All experimental tests were carried out with healthy subjects Application of PSP1.0 to the Elbow Powered Exoskeleton NEUROExos In this application we wanted to assess the usability of the PSP1.0 to measure the interaction pressure between the elbow exoskeleton NEUROExos and the user forearm surface, as well as to discriminate any user reaction to the robot action during a prototypical rehabilitation task. In particular, we were interested to discriminate between two conditions: Case 1) Case 2) no action : the user is passive and does not perform any voluntary elbow muscle activation; the robot moves user s elbow along a sinusoidal reference trajectory; pre-defined action : the user is asked to simulate a reaction to the robot action by voluntary changing (i.e., increasing or decreasing) one of the reference motion features (i.e., sinewave frequency or amplitude). The NEUROExos is an active orthosis for the rehabilitation of the elbow, able to transmit torques to the user's elbow. Its flexion-extension rotation axis is endowed with a 4-DOF passive mechanism which ensures automatic alignment between the human and the robot rotation axis [38]. NEUROExos has double-shelled links and an actively adjustable passive-compliance actuator, that together with the 4-DOF mechanism allow a highly ergonomic and safe physical interaction between the subject's arm and the orthosis (Figure 10(a)) [24]. The outer shell of each link is made of carbon fibre and transmits the force to the arm segments through inner shells made of a flexible polymeric material. The inner12 Sensors 2013, shells are composed of two valves and tailored on the subject arm surface to maximize the human-robot contact area and to improve the comfort reducing the pressure on the skin (Figure 10). Figure 10. The NEUROExos platform equipped with two PSPs 1.0. (a) PSP placement onto inner-side of exoskeleton inner-shells; front (b) and lateral (c) view of a subject wearing the NEUROExos (adapted from [33], 2011, with permission from Elsevier). For the proposed experiment, two PSPs 1.0 were placed between the forearm and the inner border of the polymeric inner shells (see Figure 10(a)). PSPs were placed as close as possible to the hand, to minimize the motion artefacts due to the skin/muscle shape changes during motion. Each PSP had its own acquisition channel and cabling. They were acquired and processed by a real-time processing unit (NI PXI-8196 RT, National Instruments Corporation, Austin, TX, USA) equipped with a multifunction data acquisition card (M-series, NI PXI-6259, National Instruments Corporation). The sensor signals (8 og signals for each PSP) were sampled at 50 khz, low-pass filtered with a moving average over 50 samples (with zero overlapping) and de-sampled at 1 khz. The pressure measured by the eight sensitive elements of each PSP was averaged to obtain the mean pressure acting on the PSP [33]. The result of this experiment was that PSP1.0 was able to record phri pressure and to detect the user reaction. For instance, this is evident from Figure 11. In this case NEUROExos was programmed to displace the user elbow joint along a 30-deg sinusoidal flexion-extension trajectory with frequency equal to 0.5 Hz. Figure 11 compares the joint trajectory and the PSP average pressure profiles (of front- and back-sides PSPs) of the two conditions no action and pre-defined action (in this specific example the user was asked to increase the sine wave pace). Indeed, reported data points out that user action results in different PSP pressure profiles: the user tries to anticipate the movement of the robot and generates a higher interaction force/torque in the same direction of the movement, i.e., higher pressure on the front- and back-side PSPs during respectively the elbow flexion and extension phases.13 Sensors 2013, Figure 11. NEUROExos joint trajectory, front- and back-side PSP1.0 pressure profiles during a prototypical rehabilitation task, with and without the user reaction. Top panel reports: the reference trajectory of the rehabilitation task (dashed line), the no action trajectory (gray line), and the pre-defined action performed by the subject (black line). Middle and bottom panels report respectively front- and back-side PSP1.0 pressure profiles: the no action condition is the gray line, the pre-defined action is the black line. Pressure profiles are averaged over ten sinusoidal motions and reported along with standard-deviation contour (dotted line). We assume that the elbow is fully extended when the joint angle is equal to zero (figure adapted from [33], 2011, with permission from Elsevier) Application of PSP1.1 to the Lower-Limb Exoskeleton LOPES In this application we wanted to assess the usability of the PSP1.1 to measure the phri pressure between the user and a lower-limb exoskeleton, and to compare the pressure estimated by the PSP1.1 with the output of a classical load cell. The LOPES is a lower-limb exoskeleton for gait training. It has three DOFs for each leg, two at the hip (i.e., flexion-extension and abduction-adduction) and one at the knee, and two DOFs to move the pelvis in the coronal and horizontal planes. LOPES joints are actuated by series elastic actuators capable of applying low-impedance torque profiles onto the corresponding human articulations and to implement virtual impedance fields [19,48]. The LOPES interfaces the human subject limbs through commercial cuffs (Hocoma AG, Volketswil, Switzerland). In particular, one cuff interfaces the thigh, and two cuffs interface the lower leg. Each cuff is realized by a flexible belt connected to a c-shape frame made of carbon fibre, which is ultimately linked to the robot linkages through steel bars (see Figure 12(a c)).14 Sensors 2013, In this experiment we equipped the right-leg thigh cuff with six PSPs placed between the leg and the belt. The six PSPs were fixed to the belt with their longitudinal axes parallel to the longitudinal axis of the limb: three PSPs were placed onto the front-side surface of the cuff, and three ones on the back side (see Figure 12(b,c)). Figure 12. (a) Overview of the LOPES exoskeleton; (b) right-leg thigh cuff sensorized with six PSPs 1.1; (c) schematic view of the right-leg sensorized cuff (adapted from [37]). (b) (a) (c) PSPs signals were acquired using a 32-channel DAQ board, with a sampling frequency of 2 khz and digitally filtered with a fourth-order Butterworth filter with a cut-off frequency of 40 Hz. Furthermore, the attachment point of the cuff to the LOPES linkage was sensorized with a 6-axis load cell (ATI Mini 45, ATI Industrial Automation) to provide a measurement reference for assessing the reliability of the PSP outcome (see Figure 12(b)). One subject walked on a treadmill within the LOPES at a constant speed of 4 km/h for about 250 gait cycles in two different conditions: Case (1) Case (2) transparent: the LOPES was controlled in zero-torque mode [49], i.e., it operated as transparent as possible; viscous field: we applied a virtual viscous field of 10 Nm/rad s 1 at the LOPES hip flexion-extension joints; the viscous field simulated a typical resistive gait training task.15 Sensors 2013, Signals from each PSP were combined to estimate the total force acting on the pad. Force profiles from each PSP were than averaged over gait cycles. Figure 13 reports, for one of the subjects, the right hip angle, the total interaction force measured by the load cell, and the force estimated by three of the six PSPs (two PSPs placed onto the frontal side, namely Front 1 and Front 2, and one PSP placed onto the back side, namely Rear 1, see Figure 12(c)) for the two above conditions (the common x-axis represents the percentage of the gait cycle). The beginning of the cycle (0 or 100%) corresponds to the foot impact on the ground. The stance phase ranges from 0 to about 50 60% of the cycle, where the toe-off takes place. The remaining part of the cycle (60 100%) corresponds to the leg swing phase. For sake of clarity, it is worth mentioning that the output of the load cell is positive when the net interaction force is higher on the front-side surface of the cuff and, vice versa, it is negative when the net interaction force is higher on the back-side of the cuff surface. Figure 13. Test of PSP1.1 on the LOPES: profiles of right hip flexion-extension angle, total interaction force measured by the load cell, and the force estimated by three of the six PSPs (i.e., Front 1, Front 2, Rear 1 ). Data are shown for two conditions: transparent and viscous field (figure adapted from [37]). Data reported in Figure 13 show two main interesting results. First, all PSPs record higher peak force in the viscous field condition. This is coherent with the fact that in the viscous-field condition the LOPES is less transparent and has a higher loading effect on the user gait. Second, there is a clear discrepancy between the output of the load cell, which represents the overall interaction force, and that16 Sensors 2013, of the PSPs. Indeed, in the central part of the mid stance (10 50% of the gait), while the resultant net force measured by the load cell is almost null, all PSPs record an increase of the interaction force. These peaks, that would not have been detected by the load cell, are much likely due to the cocontraction of the leg muscles during the stance phase, and to the consequent change in the shape and size of the thigh. In conclusion, this experiment showed that PSP1.1 were a suitable solution to monitor the phri force in a lower-limb exoskeleton, and, furthermore, provided additional information compared to localised force measurements through classical six-axis force sensors Application of PSP2.0 to Gait ysis PSP2.0 sensitive element was used to conceive and develop a pressure-sensitive foot insole to allow biomechanical assessment of gait [39]. Each insole is made of an array of 64 sensitive sensors for the measurement of the pressure over the plantar area (with the exception of the plantar arch), and an electronic board that processes and transmits wirelessly the data, sampled at 100 Hz, to a remote data logging computer via a Bluetooth connection. The developed sensorized insoles can fit into a normal sneaker shoes of EU size 42 and run continuously for up to 7 8 hours with an on-board battery. Figure 14 reports an overview of the system. Figure 14. PSP2.0-based pressure-sensitive insoles. (a) Overview of the pressure-sensitive insole on the bench; (b) two pressure-sensitive insoles integrated into normal sneaker shoes. (a) (b) Pressure-sensitive insole voltage signals are online converted into pressure values through a pre-computed calibration function and a Laplacian surface of smoothing is applied to the pressure map to remove pressure outliers and regularize the surface. The pressure map is used to extract the values of the vertical ground reaction force (vgrf), the position of the centre of pressure and the partial forces on the foot tip and heel. These variables, together with their first-order time derivatives, are of high interest in gait ysis and have been used to develop an automated gait segmentation algorithm using a common machine learning technique, Hidden Markov Model [50,51]. As an example of the performance of the pressure-sensitive insoles, Figure 15 reports the variation of the vgrf of both feet during the gait. For both feet, it is possible to distinguish the principal phases17 Sensors 2013, of the gait [47], that are: (i) the contact of the foot with the floor, corresponding to the increasing of the vgrf until the first peak, (ii) the mid-stance phase, corresponding to the variation of vgrf until the second peak, (iii) the pre-swing phase, corresponding to the decreasing of the vgrf, and (iv) the swing phase, zero force on the insole. Figure 15. Gait phases recognition through the pressure-sensitive insole for both left (top panel) and right (bottom panel) feet Application of PSP2.1 to the Lower-Limb Exoskeleton LOPES The objective of this application was to assess the usability of the new PSP2.1-based LOPES sensorized cuff to measure the phri force between the user limb and the exoskeletal attachment points. In this application scenario, all of the six LOPES cuffs were sensorized with two PSP2.1 arrays (see Figure 16). Thigh cuffs were covered with two 8 4 sensitive arrays, one for the front- and one for the back-side surface of the cuff. Shank and ankle cuffs were covered with two 4 4 sensitive arrays. As for the pressure-sensitive insoles, data from cuffs were collected, processed and wirelessly transmitted to a remote PC by a custom electronic board. Through the custom electronic board, data from each cuff were sampled at 1.8 khz, low-pass filtered and de-sampled at 100 Hz, and finally transmitted to the remote PC through a Bluetooth connection. Electronic boards were fixed on the exoskeleton using a custom box, which houses the electronics, the Bluetooth transmitter and the battery (Figure 16). To test the usability of the new sensorized cuffs, we performed the following experimental protocol. Three subjects walked on a treadmill within the LOPES, in three different conditions: (1) the subject walked at a constant speed of 2.5 km/h with an assistive torque for the hip flexion-extension (all other LOPES joints were controlled in zero-torque mode); (2) the subject walked at a constant speed of 4 km/h with an assistive torque for the hip flexion-extension (all other LOPES joints were controlled in zero-torque mode); (3) the subject walked at a constant speed of 4 km/h without any assistive torque (all LOPES joints were controlled in zero-torque mode).18 Sensors 2013, Figure 16. New PSP2.1-based LOPES sensorized cuffs. (a) Overview of the 8 4 and 4 4 sensitive arrays; (b) sensorized thigh cuff; (c) sensorized shank and ankle cuffs; (d) overview of the LOPES with all of the six cuffs endowed with PSPs 2.1. (a) (b) (c) (d) Assistive torque to hip flexion-extension was provided by means of the adaptive assistive algorithm based on the use of motor primitives proposed in [52]. For each (front- and back-side array) we computed the total force applied on it. For each of the above three conditions, Figure 17 reports, for one of the subjects, the following data averaged over 20 gait cycles: right-leg hip flexion-extension angle and torque, total force recorded by the front- and back-side PSP arrays of the right-leg thigh cuff. In Figure 17 mean profiles (solid coloured lines) of all variables are reported with standard deviation (shadowed contours) along the gait cycle, expressed in percentage. Table 3 summarises for all of the three subjects the mean and maximum force values (averaged over 20 gait cycles) recorded by the PSPs of the right-leg thigh cuffs.19 Sensors 2013, Figure 17. Hip kinematic and dynamic variables for Subject #1: right-leg hip flexion-extension joint angle and torque, and total force recorded by front- (F-S) and back-side (B-S) thigh-cuff PSPs. Data are averaged over 20 gait cycles (solid line), and shown along with the standard deviation contour (shadowed), for three conditions: (a) gait velocity is 2.5 km/h, with assistive torque; (b) gait velocity is 4 km/h, with assistive torque; (c) gait velocity is 4 km/h without assistive torque.20 Sensors 2013, Table 3. Mean and standard deviation of maximum and average force recorded by right-leg thigh cuff front- and back-side PSPs 2.1 during a gait cycle. Data are reported for the three different gait conditions (i.e., gait velocity equal to 4 km/h, with and without assistive torque, and gait velocity equal to 2.5 km/h with assistive torque) and the three subjects. Maximum and average force values are averaged over 20 gait cycles. Maximum force [N] Average force [N] Maximum force [N] Average force [N] Front-side Back-side Gait velocity: 4 km/h, assistance: NO Subject # ± ± ± ± 2.20 Subject # ± ± ± ± 0.70 Subject # ± ± ± ± 0.56 Gait velocity: 4 km/h, assistance: YES Subject # ± ± ± ± 1.04 Subject # ± ± ± ± 0.39 Subject # ± ± ± ± 0.28 Gait velocity: 2.5 km/h, assistance: YES Subject # ± ± ± ± 1.13 Subject # ± ± ± ± 0.48 Subject # ± ± ± ± 0.35 Results reported in Figure 17 and Table 3 point out that the PSPs actually record three different phri force patterns, for the three different conditions. Indeed, in the case of gait velocity equal to 2.5 km/h, front- and back-side PSPs measure a slightly changing value of force along the gait cycle. Furthermore, for all subjects, the maximum and the average values of force applied on the PSPs are the lowest ones, between the three gait conditions. This result is in line with results achieved in previous works [52]: this level of assistance, at this gait speed, renders the LOPES more transparent, thus reducing the interaction force. Indeed, the force recorded by the PSPs represents the preloading force for fastening the cuff around the user limb. On the other hand, in the case of gait velocity equal to 4 km/h the PSP force profiles vary along the gait cycle: two different patterns can be recognized depending on the presence/absence of the torque assistance. When the assistance is on, the front-side pad shows a decreasing of the interaction force between the toe-off and the middle-swing phases (50 80% of the gait cycle), while the back-side pad measures a peak in the middle of the swing phase (around 80% of the gait cycle). This is mostly due to the action of the assistive torque in the flexion direction. It is also worth noting that the peak of the interaction force recorded by the back-side pad is delayed about 10% of the gait cycle compared to the peak of the assistive flexion torque (around 70% of the gait cycle). This delay is due to the phri dynamics: human limb and robot link are not rigidly connected: before the torque is actually transmitted from the robot to the user, muscle and other soft tissues must be squeezed by the cuff, thus generating a delay in the mechanical transmission. When the assistance is off, both the front- and back-side pads show a peak force in correspondence of the maximum joint angle acceleration, respectively at the end of the stance phase (60% of the gait cycle) and at the end of the swing phase (0% of the gait cycle). This pattern is well explained by the fact that in this case since no assistance is provided by the robot, the subject transfer mechanical power to the robot to accelerate/decelerate its linkages.21 Sensors 2013, Conclusions In this paper we overviewed the evolution of the pressure-sensitive technology developed at Scuola Superiore Sant Anna, based on an opto-electronic transduction principle which allows to monitor pressure distribution at the phri surface, as well as at the foot-ground interface. The presented works show the importance of the silicon cover for the proposed technology: it plays a crucial role in the transduction principle, and enhances the scalability of the PSPs in terms of: (i) overall size of the sensitive area (we passed from the mm 2 of the PSP1 to the mm 2 if the PSP2.0 used for the pressure-sensitive foot insole); (ii) number of sensitive elements, (iii) pressure sensitive range, that we explored from 8.3 kpa (in the case of PSP1) up to 500 kpa for the sensorized insole. In all application scenarios PSPs showed relevant performance and validated the proposed approach to monitor the phri pressure/force, despite the non-ideal non-uniform load distribution on the top surface of the silicon cover (being the non-uniform load distribution a result of the interaction of the PSP with a curved surface, such as the one of limb segments or the sole). These results confirmed the capability of the technology to estimate with good accuracy the load also when interacting with a curved indenting surface, as early demonstrated by bench tests in [37], provided that its curvature radius is sufficiently high compared to the size of the top surface of the PSP silicone cover. Furthermore, successful use of the proposed technology was possible also thanks to: (i) the possibility to assemble the PSP on a flexible PCB (this is the case of the PSP2.0 and PSP2.1 arrays), (ii) the wireless connection, (iii) the low-power consumption (in the case of the insole the maximum requested power is about 0.5 W), and (iv) the inherent cost effectiveness of the technology. Future works aim at exploiting the proposed technology and its application examples in intensive applications in both laboratory and clinical settings. For instance, the sensorized insole will be used to monitor the gait of lower-limb amputees to provide them with an augmenting proprioceptive feedback from the missing limb [53]. In addition, a sensorized mat with more than four thousands of PSP2.1 sensitive elements will be used to monitor the posture of preterm infants during the rehabilitation process, similarly to what has been proposed recently in [54,55]. Acknowledgements The authors would like to thank Domen Novak, Peter Reberšek and Tadej Beravs for their support in the preparation of the experimental setup in the Biomechanical Engineering Laboratory of University of Twente for the experiments carried out with the LOPES. This work was partly supported by: EU within the EVRYON Project (FP7/ Grant Agreement No ), the CYBERLEGs Project (FP7/ Grant Agreement No ), the CareToy Project (FP7/ Grant Agreement No ), and the WAY project (FP7/ Grant Agreement No ); Regione Toscana under the Health Regional Research Programme 2009 within the project EARLYREHAB; the Italian Government within the national AMULOS Project, Industria 2015, grant agreement MI01_00319.22 Sensors 2013, References 1. Turchetti, B.G.; Micera, S.; Cavallo, F.; Odetti, L.; Dario, P. Technology and innovative services. IEEE Pulse 2011, 2, Leven, J.; Burschka, D.; Kumar, R.; Zhang, G.; Blumenkranz, S.; Dai, X.; Award, M.; Hager, G.D.; Marohn, M.; Choti, M.; et al. DaVinci Canvas: A telerobotic surgical system with integrated, robot-assisted, laparoscopic ultrasound capability. Med. Image Comput. Comput. Assist. Interv. 2005, 8, Masia, L.; Krebs, H.I.; Cappa, P.; Hogan, N. 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Siva Kumar 2, K.Susmitha 2, D.Tarun 3 and A.Srinath 4 1 K L University/Mechanical Engineering, Vaddeshwaram, Guntur District, An assisting robotic system for rehabilitation and training of elderly people Marco Ceccarelli LARM: Laboratory of Robotics and Mechatronics DICeM; University of Cassino and South Latium Via Di Biasio H E A L T H & F I T N E S S E Q U I P M E N T HUR Rehab Line HUR naturally different Contents HUR naturally different HUR SmartCard 1 HUR Rehab Line key to rehabilitation 2 SmartCard FCM Rehab Line computerized THE COMPOSITE DISC - A NEW JOINT FOR HIGH POWER DRIVESHAFTS Dr Andrew Pollard Principal Engineer GKN Technology UK INTRODUCTION There is a wide choice of flexible couplings for power transmission applications, CENG 732 Computer Animation Spring 2006-2007 Week 8 Modeling and Animating Articulated Figures: Modeling the Arm, Walking, Facial Animation This week Modeling the arm Different joint structures Walking On Predicting Lower Leg Injuries for the EuroNCAP Front Crash Thomas Hofer, Altair Engineering GmbH Peter Karlsson, Saab Automobile AB Niclas Brännberg, Altair Engineering AB Lars Fredriksson, Altair Engineering Scooter, 3 wheeled cobot North Western University A cobot is a robot for direct physical interaction with a human operator, within a shared workspace PERCRO Exoskeleton Unicycle cobot the simplest possible The WalkOn Range Dynamic Lower Leg Orthoses NeW Information for physicians, orthotists and physiotherapists One Range Many Different Applications The WalkOn product range allows you to address the specific REHABILITATION CONCEPT FOR THE LOWER LIMBS Life by motion LAMBDA CONCEPT The Lambda is the only rehabilitation device that offers the freedom of a plan workspace in which the leg can be manipulated throughout Finite Element ysis of a Total Knee Replacement Simone Machan Supervisor: Ass. Prof. Dennis Bobyn Company: Australian Surgical Design and Manufacture Research Goals: Static ysis STANCE Aim: To Mechanics of human movement M. Foidart-Dessalle (Prof. FM, ULg) S. Cescotto (Prof. FSA, ULg) F. Pascon (FNRS) 1 Structures implied in movement Bones and Joints: Moving Structures Motor forces: Gravity, HAL: Hybrid Assistive Limb based on Cybernics Yoshiyuki Sankai Global COE Cybernics, System and Information Engineering, University of Tsukuba 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8573, Japan Abstract Design of an Arm Exoskeleton Controlled by the EMG Signal Mark Novak Cornel College PHY312 December 2011 Professor Derin Sherman Introduction An exoskeleton is a supporting structure on the outside of Determining the Posture, Shape and Mobility of the Spine The World of Biomechanics Assessment of the Mobility Function Using a special Triple Cervical marker set comprising miniature ultrasound transmitters, Gait Cycle: The period of time from one event (usually initial contact) of one foot to the following occurrence of the same event with the same foot. Abbreviated GC. Gait Stride: The distance from initial Force measurement Forces VECTORIAL ISSUES In classical mechanics, a force is defined as "an action capable of modifying the quantity of movement of a material point". Therefore, a force has the attributes CALIBRATION OF A ROBUST 2 DOF PATH MONITORING TOOL FOR INDUSTRIAL ROBOTS AND MACHINE TOOLS BASED ON PARALLEL KINEMATICS E. Batzies 1, M. Kreutzer 1, D. Leucht 2, V. Welker 2, O. Zirn 1 1 Mechatronics Research SAFE A HEAD Structural ysis and Finite Element simulation of an innovative ski helmet Prof. Petrone Nicola Eng. Cherubina Enrico Goal Development of an innovative ski helmet on the basis of yses The 2002 International Congress and Exposition on Noise Control Engineering Dearborn, MI, USA. August 19-21, 2002 Acoustic ysis of an induction motor with viscoelastic bearing supports H.G. Tillema VDA Dynamic Measurement of Brake Pads Material Parameter 315 This non-binding recommendation by the German Association of the Automotive Industry (VDA) has the following objectives: This standard treats Design, Fabrication and ysis of Bipedal Walking Robot Vaidyanathan.V.T 1 and Sivaramakrishnan.R 2 1, 2 Mechatronics, Department of Production Technology, Madras Institute of Technology, Anna University, International Journal of Modern Manufacturing Technologies ISSN 267 364, Vol. I, No. 1 / 29 71 THEORETICAL AND EXPERIMENTAL INVESTIGATION OF AN ORTHOGLIDE MECHANISM USED IN CNC MILLING MACHINE Sevasti Piezo Elements for a Multitude of Sensor Applications From Level Measurement to Adaptive Systems Technology PI Ceramic GmbH, Lindenstraße, 07589 Lederhose, Germany Page 1 of 5 The Piezo Effect Piezoelectric Design Considerations for an Active Soft Orthotic System for Shoulder Rehabilitation Samuel B. Kesner, Student Member, IEEE, Leif Jentoft, Student Member, IEEE, Frank L. Hammond III, Member, IEEE, Robert ACE s Essentials of Exercise Science for Fitness Professionals Chapter 3: Fundamentals of Applied Kinesiology Learning Objectives Upon completion of this chapter, you will be able to: Describe certain LECTURE 6 TOPIC: BIOPHYSICAL BASICS OF ULTRASOUND IMAGING TIME: 2 HOURS Ultrasound is a term given to inaudible, high frequency sound waves and is also the generic name given to the imaging modality that Numerical ysis of Independent Wire Strand Core (IWSC) Wire Rope Rakesh Sidharthan 1 Gnanavel B K 2 Assistant professor Mechanical, Department Professor, Mechanical Department, Gojan engineering college, Tire testing at real driving conditions and at tthe test tstand Intelligent Tire Technology 26 28 September 2011 Darmstadt Content Motivation Measurement Equipment Approach Test description Results Conclusions 111 Nonlinear Models of Reinforced and Post-tensioned Concrete Beams ABSTRACT P. Fanning Lecturer, Department of Civil Engineering, University College Dublin Earlsfort Terrace, Dublin 2, Ireland. Email: Abaqus Technology Brief Automobile Roof Crush ysis with Abaqus TB-06-RCA-1 Revised: April 2007. Summary The National Highway Traffic Safety Administration (NHTSA) mandates the use of certain test procedures Purpose: Lab # 3 - Angular Kinematics The objective of this lab is to understand the relationship between segment angles and joint angles. Upon completion of this lab you will: Understand and know how PhD Presentation, Nov. 9 2011, Pisa CV of BioRobotics Arianna Menciassi Christian Cipriani The BioRobotics Institute Pontedera, 20 km from Pisa, 15 minutes by train 2 Full Professors 3 + 1 Associate Professors Fluid Structure Interaction VI 3 Fluid structure interaction of a vibrating circular plate in a bounded fluid volume: simulation and experiment J. Hengstler & J. Dual Department of Mechanical and Process International Review of Applied Engineering Research. ISSN 2248-9967 Volume 4, Number 5 (2014), pp. 417-422 Research India Publications http://www.ripublication.com/iraer.htm Automatic Control Using Haptics DEVELOPMENT OF A GRIP AND THERMODYNAMICS SENSITIVE PROCEDURE FOR THE DETERMINATION OF TYRE/ROAD INTERACTION CURVES BASED ON OUTDOOR TEST SESSIONS Flavio Farroni, Aleksandr Sakhnevych, Francesco Timpone School of Engineering Department of Electrical and Computer Engineering 332:224 Principles of Electrical Engineering II Laboratory Experiment 2 Frequency Response of Filters 1 Introduction Objectives To Control a Bipedal Humanoid Robot Using NI LabVIEW Segment: Academic Country: Singapore Author(s): Wee Teck Chew, Kang Biao, Qu Sai and Zhang Lu, School of Engineering, Temasek Polytechnic Product: NI LabVIEW Prof. Alexandr Belostotskiy, Assoc. Prof. Sergey Dubinsky, PhD student Sergey Petryashev, PhD student Nicolay Petryashev Computational ysis of Stress-strain State, Dynamics, Strength and Stability Véronique PERDEREAU ISIR UPMC mars 2013 Conventional methods applied to rehabilitation robotics Véronique Perdereau 2 Reference Robot force control by Bruno Siciliano & Luigi Villani Kluwer Academic Publishers Equipment Reflection and Refraction Acrylic block set, plane-concave-convex universal mirror, cork board, cork board stand, pins, flashlight, protractor, ruler, mirror worksheet, rectangular block worksheet, Hydraulic Displacement Amplification System for Energy Dissipation Tracy S.K. Chung and Eddie S.S. Lam ABSTRACT An energy dissipation system with displacement amplification is presented. Displacement amplification Product Introduction MyoMuscle Telemyo DTS-System Telemetry system for EMG and Biomechanical Sensors DTS Device Family 3 major device categories can be used for the Direct Transmission System technology Closed-Loop Motion Control Simplifies Non-Destructive Testing Repetitive non-destructive testing (NDT) applications abound, and designers should consider using programmable motion controllers to power Properties Free of float metal bellow coupling with integrated torque measurement Non-contact measurement system, high robustness High torsional stiffness Limited torque of inertia Performance Measurement STUDY OF DAM-RESERVOIR DYNAMIC INTERACTION USING VIBRATION TESTS ON A PHYSICAL MODEL Paulo Mendes, Instituto Superior de Engenharia de Lisboa, Portugal Sérgio Oliveira, Laboratório Nacional de Engenharia Acceleration Introduction: Acceleration is defined as the rate of change of velocity with respect to time, thus the concepts of velocity also apply to acceleration. In the velocity-time graph, acceleration Improved Three-dimensional Image Processing Technology for Remote Handling Auxiliary System Chiaki Tomizuka Keisuke Jinza Hiroshi Takahashi 1. Introduction Remote handling devices are used in the radioactive EACS 2012 5 th European Conference on Structural Control Genoa, Italy 18-20 June 2012 Paper No. # 202 An Adaptive Pneumatic Shock-Absorber with a Piezo-valve under Harmonic Loading Grzegorz MIKUŁOWSKI, Research-Grade Research-Grade Motion Motion Capture Capture The System of Choice For Resear systems have earned the reputation as the gold standard for motion capture among research scientists. With unparalleled 5-Axis Test-Piece Influence of Machining Position Michael Gebhardt, Wolfgang Knapp, Konrad Wegener Institute of Machine Tools and Manufacturing (IWF), Swiss Federal Institute of Technology (ETH), Zurich, JOURNAL OF CURRENT RESEARCH IN SCIENCE (ISSN 2322-5009) CODEN (USA): JCRSDJ 2014, Vol. 2, No. 2, pp:277-284 Available at www.jcrs010.com ORIGINAL ARTICLE EXPERIMENTAL AND NUMERICAL YSIS OF THE COLLAR Topic 5: Measurement and ysis of EMG Activity Laboratory Manual Section 05 HPHE 6720 Dr. Cheatham What is Electromyography (EMG)? Electromyography (EMG) is an experimental technique concerned with Robotics ABB Robotics Laser Cutting Software High precision laser cutting made easy - Greater manufacturing flexibility at lower capital investment Robotic laser cutting Overview Allows for the increased Home Browse Search My settings My alerts Shopping cart Articles All fields Author Images Journal/Book title Volume Issue Page Se Thumbnails Full-Size images View View Page 2 of 11 2. Formulation of the Mini-trampoline vibration exciter- Force measurements Leonard L. KOSS 1 ; Vincent ROUILLARD 2 1 Monash University, Australia 2 Victoria University, Australia ABSTRACT A mini-trampoline has been previously Gait Review of Last Lecture - TE Interventions to increase flexibility Generating muscle force depends on Open chain vs. closed chain PNF Balance strategies Benefits of aerobic exercise Gait An individual Biomechanical ysis of the Deadlift (aka Spinal Mechanics for Lifters) Tony Leyland Mechanical terminology The three directions in which forces are applied to human tissues are compression, tension, Advance in Electronic and Electric Engineering. ISSN 2231-1297, Volume 3, Number 5 (2013), pp. 601-606 Research India Publications http://www.ripublication.com/aeee.htm Hand Gestures Remote Controlled The zebris FDM-System-Gait ysis for Research and Clinical Applications The World of Biomechanics The zebris FDM-System- Easy and Accurate Gait ysis The new zebris FDM measuring system functions A Fuzzy System Approach of Determination for CNC Milling Zhibin Miao Department of Mechanical and Electrical Engineering Heilongjiang Institute of Technology Harbin, China e-mail:miaozhibin99@yahoo.com.cn Basic Biomechanics Biomechanics is the study of the body in motion. Foot biomechanics studies the relationship of the foot to the lower leg. During walking and running the musculoskeletal system generates Helmholtz Coils A useful laboratory technique for getting a fairly uniform magnetic field, is to use a pair of circular coils on a common axis with equal currents flowing in the same sense. For a given Team Workshop Problem 17 The Jumping Ring Prof. E.M. Freeman and Prof. D.A. Lowther EMF is at the EED/CST London, UK, e-mail 10016.3130@Compuserve.com from Internet. DAL is at the EED/McGiII, Canada, e-mail Laboratory 4 Torsion Testing Objectives Students are required to understand the principles of torsion testing, practice their testing skills and interpreting the experimental results of the provided materials Shadow Dexterous Hand C6M2 Technical Specification Current Release 27st June 212 1/13 Table of Contents 1 Overview...4 2 Mechanical Profile...5 2.1 Dimensions...5 2.2 Kinematic structure...6 2.3 Weight...6 BTS GEMINI is the complete solution for functional and quantitative evaluation of pathologies involving spinal pain, balance disorders, spinal deformities and structural misalignments. BTS GEMINI permits ENS 7 Paris, France, 3-4 December 7 FRICTION DRIVE SIMULATION OF A SURFACE ACOUSTIC WAVE MOTOR BY NANO VIBRATION Minoru Kuribayashi Kurosawa, Takashi Shigematsu Tokyou Institute of Technology, Yokohama Indian Journal of Biomechanics: Special Issue (NCBM 7-8 March 2009) Prosthetic Foot Design for Transtibial Prosthesis Ranjan Das, M.D Burman, Sagar Mohapatra, Department of prosthetics & Orthotics, S.V.Nirtar, DIGITAL-TO-OGUE AND OGUE-TO-DIGITAL CONVERSION Introduction The outputs from sensors and communications receivers are ogue signals that have continuously varying amplitudes. In many systems RESEARCH ARTICLE ISSN: 2321-7758 DESIGN AND DEVELOPMENT OF A DYNAMOMETER FOR MEASURING THRUST AND TORQUE IN DRILLING APPLICATION SREEJITH C 1,MANU RAJ K R 2 1 PG Scholar, M.Tech Machine Design, Nehru College w Technical Product Information Precision Miniature Load Cell with Overload Protection 1. Introduction The load cells in the model 8431 and 8432 series are primarily designed for the measurement of force Related topics Centripetal force, rotary motion, angular velocity, apparent force, use of an interface. Principle and task As an object moves on a circular path with a certain angular velocity, it is constantly Introduction to Mechanical Behavior of Biological Materials Ozkaya and Nordin Chapter 7, pages 127-151 Chapter 8, pages 173-194 Outline Modes of loading Internal forces and moments Stiffness of a structure Advantages of for Servo-motors Executive summary The same way that 2 years ago computer science introduced plug and play, where devices would selfadjust to existing system hardware, industrial motion control Scanning Acoustic Microscopy Training This presentation and images are copyrighted by Sonix, Inc. They may not be copied, reproduced, modified, published, uploaded, posted, transmitted, or distributed An Accelerometer Based Hand Gesture Recognition Digital Pen Asmita Bodhale 1 Swati Musale 2 Prof. Prakash Sontakke 3 Dept. of ECE, Pimpri Chinchwad Dept. of ECE, Pimpri Chinchwad Dept. of ECE, Pimpri Chinchwad Things to remember: Constant Leg Dominant Pain Self-Management Programme 1. Prolonged bed rest is not recommended and can hinder recovery 2. Schedule periods of activity with rest throughout the day 3. Technical Information Encoders for Linear Motors in the Electronics Industry The semiconductor industry and automation technology increasingly require more precise and faster machines in order to satisfy Journal of Mechanics Engineering and Automation 5 (2015) 180-184 doi: 10.17265/2159-5275/2015.03.007 D DAVID PUBLISHING Design and ysis of Self-excited Miniature Magnetic Generator Wu-Sung Yao and Loss Control TIPS Technical Information Paper Series Innovative Safety and Health Solutions SM Portable Computers and Ergonomics Introduction The use of portable computers continues to increase as the Zigbee-Based Wireless Distance Measuring Sensor System Ondrej Sajdl 1, Jaromir Zak 1, Radimir Vrba 1 1 Department of Microelectronics, Brno University of Technology, FEEC, Udolni 53, 602 00 Brno, Czech Real Time Simulation for Off-Road Vehicle ysis Dr. Pasi Korkealaakso Mevea Ltd., May 2015 Contents Introduction Virtual machine model Machine interaction with environment and realistic environment UDC 624. 042. 7 Development of U-shaped Steel Damper for Seismic Isolation System Kazuaki SUZUKI* 1 Atsushi WATANABE* 1 Eiichiro SAEKI* 1 Abstract Seismic isolation system was widely admitted after Hanshin-Awaji 1 Variable Stiffness Actuation based on Dual Actuators Connected in Series and Parallel Prof. Jae-Bok Song (jbsong@korea.ac.kr ). (http://robotics.korea.ac.kr) ti k Depart. of Mechanical Engineering, Korea Knee Kinematics and Kinetics Definitions: Kinematics is the study of movement without reference to forces http://www.cogsci.princeton.edu/cgi-bin/webwn2.0?stage=1&word=kinematics Kinetics is the study 3 GENERATORS An important application area for is in the conversion of mechanical energy into electrical energy, and this chapter describes the conditions under which should be used to convert the maximum Range of Motion A guide for you after spinal cord injury Spinal Cord Injury Rehabilitation Program This booklet has been written by the health care providers who provide care to people who have a spinal EGR 315 Design Project - 1 - Executive Summary Vibrations can have an adverse effect on the accuracy of the end effector of a multiple-link robot. The ability of the machine to move to precise points scattered HYSTERESIS IN MAGNETIC MATERIALS A5 1 Experiment A5. Hysteresis in Magnetic Materials Objectives This experiment illustrates energy losses in a transformer by using hysteresis curves. The difference betwen The purpose of this introduction to dynamic simulation project is to explorer the dynamic simulation environment of Autodesk Inventor Professional. This environment allows you to perform rigid body dynamic User Guide MTD-3 Motion Lab Systems, Inc. This manual was written by Motion Lab Systems using ComponentOne Doc-To-Help. Updated Tuesday, June 07, 2016 Intended Audience This manual is written to provide Hippocrates (460-377 B.C.) Biomechanics of Joints, s and Tendons. Course Text: Hamill & Knutzen (some in chapter 2 and 3, but ligament and tendon mechanics is not well covered in the text) Nordin & Frankel







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