Human joint impedance identification


The technology for building prostheses, orthoses and exoskeletons has boomed in the last decade. People that are suffering from physical disabilities can count on increasingly reliable supportive tools (orthoses) and artificial limbs (prostheses) to improve their quality of life. Modern prostheses and orthoses are provided with sensors and actuators to measure relevant quantities (torque, angle) and to inject mechanical power when necessary, such that disabled people can perform tasks which, otherwise, would not be feasible (walking upright and up/down stairs, lifting loads,..).

In this context, one important challenge is the human. Although sensors are available, the interpretation of the measured data is not straightforward. The human is a system with a will of his own, and can behave quite unpredictably. Nevertheless, a correct interpretation is essential to understand in which state the human joints are (e.g. which phase of walking?), and to correctly tune the control parameters, such that the artificial limb works nicely in concert with the human's intention.



In this thesis, we will explore the possibilities of orthoses and exoskeletons, available at the Brubotics research department, to allow for a correct estimation of the human joint's state. The latter is mainly determined by the muscle activation level, the angle of the joint, and the contact points with the environment. During the work, security measures and care will have to be taken, to guarantee the safety of the humans, and the proper handling of the machines. An important part of the work will consist of the characterisation of sensors and actuators (some of which are custom made), to be used for the tracking of human joint impedances, in view of implementing patient specific control strategies. Multiple identification tools, available at the ELEC department, will be tried out and adapted where necessary, and the requirements on the instrumentation will be investigated.

Carlos Rodriguez Guerrero
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