Design and modeling of an exoskeleton torque sensor

Controlling the upper limb with force feedback requires the continuous measurement of multiple values, so it is necessary to use a specific measuring system. The position of the joints and the torque produced by the drives are the basic feedbacks necessary for control. Measurement of the joint positions does not cause complications, while measurement of the driving torque is much more complex. This article describes the methods of implementing an exoskeleton drive system through a closed loop conduit system based on Bowden cables, and the integration of a torque sensor within the wheel of the exoskeleton. The integration of the sensor within a mechanical part of the construction of the exoskeleton is the main advantage of the developed sensor because it does not affect the dynamics of the exoskeleton. This article presents the process of designing, calibrating and validating the proposed link wheel torque sensor.