On the Mass Center of Articulated Chains

Espiau, Bernard

doi:10.1007/978-94-015-9064-8_19

Cited by 15 publications

(19 citation statements)

References 7 publications

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“…The values in r i describe the geometry of the SESC and can be explicitly determined as a function of the links' masses, their CoM position in the local reference frame, and the distance between the origins of two consecutive frames. For details on how to obtain r i , please refer to [11], [12], [14].…”

Section: A Model Definitionmentioning

confidence: 99%

“…These parameters can be thought of as containing the geometric description of the links of a virtual, open, serial chain whose end-effector is attached to the original chain's CoM. This chain is known as the statically equivalent serial chain (SESC) [11], [12].…”

Section: A Model Definitionmentioning

confidence: 99%

“…The SESC method was introduced by Espiau and Boulic [11] for the control of a tree shaped, linked structure. It was first applied by Cotton el al.…”

Section: Introductionmentioning

confidence: 99%

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Online identification and visualization of the statically equivalent serial chain via constrained Kalman filter

González

Hayashibe

Fraisse

2013

2013 IEEE International Conference on Robotics and Automation

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A human's center of mass (CoM) trajectory is useful to evaluate the dynamic stability during daily life activities such as walking and standing up. To estimate the subjectspecific CoM position in the home environment, we make use of a statically equivalent serial chain (SESC) developed with a portable measurement system. In this paper we implement a constrained Kalman filter to achieve an online estimation of the SESC parameters while accounting for the human body's bilateral symmetry. This results in constraining SESC parameters to be consistent with the human skeletal model used. The proposed identification method can inform the subject or the therapist, in real-time, about the quality of the on-going CoM estimation. This information can be helpful to reduce the identification time and establish a personalized protocol. A Kinect is used as a markerless motion capture system for measuring limb orientations while the Wii board is used to measure the subject's center of pressure (CoP) during the identification phase. CoP measurements and Kinect data were recorded for four able-bodied subjects. The recorded data was then given to the proposed recursive algorithm to identify the parameters of the SESC online. A cross-validation test was performed to verify the identification performance. The results for these subjects are shown and discussed.

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Section: A Model Definitionmentioning

confidence: 99%

Section: A Model Definitionmentioning

confidence: 99%

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Online identification and visualization of the statically equivalent serial chain via constrained Kalman filter

González

Hayashibe

Fraisse

2013

2013 IEEE International Conference on Robotics and Automation

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“…During the stance phase, new constraints appear, which can be modelled either as unilateral (see [22]) or, more often as bilateral. Therefore, the model has to be modified in order to incorporate the constraints in the following way (see full developments in [21]). …”

Section: Constrained Casementioning

confidence: 99%

Can an underactuated leg with a passive spring at the knee achieve a ballistic step?

Espiau

Guigues

Pissard-Gibollet

2000

Experimental Robotics VI

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Abstract:In this paper, we present the design and the results of a control scheme aimed at moving an underactuated double pendulum simulating a leg. The system is actuated at the hip and includes a spring at the knee. It interacts with the grou nd, which is in fact a treadmill, through a telescopic foot made of a linear spri ng and a damper. The control scheme is different in the 2 phases, swing and stance, and a repetitive step is achieved by switching between these two controls. The paper describes the used models, the control algorithms and their implementation. It pr esents also experimental results of the approach. Key-words:

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“…To overcome this limitation the statically equivalent serial chain (SESC) was introduced by Cotton et al [6] as a tool for CoM estimation in humans, based on the work of Espiau and Boulic [7]. After the method was validated for the control of humanoid robots, Cotton et al [6] used it to estimate the CoM position of a young individual on the sagittal plane.…”

Section: Introductionmentioning

confidence: 99%

Center of Mass Estimation for Rehabilitation in a Multi-contact Environment: A Simulation Study

González

Hayashibe

Demircan

et al. 2013

2013 IEEE International Conference on Systems, Man, and Cybernetics

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Abstract-Center of mass (CoM) estimation can be used to evaluate human stability during rehabilitation. A personalized estimation can be obtained using the serial equivalent static chain (SESC) method, calibrated using a series of static postures. The estimation accuracy is dependent on the number and quality of poses used during calibration. Currently, this limits the method's application to unimpaired individuals. We present a preliminary study of a SESC identified in a multi-contact scenario during a Sit-to-Stand task. Stanford's SAI (Simulation and Active Interface) platform was used to emulate motion and predict relevant reaction forces. The CoM estimation obtained is valid for motions similar to those used during identification. Using a threedimensional model, the estimated mean error was less than 26 millimetres for a Sit-to-Stand task involving displacements along all axes. As such, personalized CoM estimation can be available for patients with a limited range of whole body motion.

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On the Mass Center of Articulated Chains

Cited by 15 publications

References 7 publications

Online identification and visualization of the statically equivalent serial chain via constrained Kalman filter

Online identification and visualization of the statically equivalent serial chain via constrained Kalman filter

Can an underactuated leg with a passive spring at the knee achieve a ballistic step?

Center of Mass Estimation for Rehabilitation in a Multi-contact Environment: A Simulation Study

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