Sensing and Control of a Multi-Joint Soft Wearable Robot for Upper-Limb Assistance and Rehabilitation


T. Proietti, et al., “Sensing and Control of a Multi-Joint Soft Wearable Robot for Upper-Limb Assistance and Rehabilitation,” IEEE Robotics and Automation Letters, vol. 6, no. 2, pp. 2381-2388, 2021.
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In the field of wearable robotics, there has been increased interest in the creation of soft wearable robots to provide
assistance and rehabilitation for those with physical impairments.
Compared to traditional robots, these devices have the potential to
be fully portable and lightweight, a flexibility that may allow for
increased utilization time as well as enable use outside of a clinical
environment. In this letter, we present a textile-based multi-joint
soft wearable robot to assist the upper limb, in particular shoulder
elevation and elbow extension. Before developing a portable fluidic
supply system, we leverage an off-board actuation system for power
and control, with the worn components weighting less than half
kilogram. We showed that this robot can be mechanically transparent when powered off, not restricting users from performing
movements associated with activities of daily living. Three IMUs
were placed on the torso, upper arm and forearm to measure the
shoulder and elbow kinematics. We found an average RMSE of
∼5 degrees when compared to an optical motion capture system.
We implemented dynamic Gravity Compensation (GC) and Joint
Trajectory Tracking (JTT) controllers that actively modulated
actuator pressure in response to IMU readings. The controller performances were evaluated in a study with eight healthy individuals.
Using the GC controller, subject shoulder muscle activity decreased
with increasing magnitude of assistance and for the JTT controller,
we obtained low tracking errors (mean ∼6 degrees RMSE). Future
work will evaluate the potential of the robot to assist with activities
in post-stroke rehabilitation.

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Last updated on 08/10/2021