A Spatial-Motion Assist-as-Needed Controller for the Passive, Active, and Resistive Robot-Aided Rehabilitation of the Wrist

Abstract

Demand for robot-assisted therapy has increased at every stage of the neurorehabilitation recovery. This paper presents a controller that is suitable for the assist-as-needed (AAN) training of the wrist when performing the spatial motion. A compact wrist exoskeleton robot is presented to realize the AAN controller. This wrist robot includes series elastic actuators with high torque-to-weight ratios to provide accurate force control required for the AAN controller. In addition to assist-as-needed rehabilitation, the parameters of the AAN controller can be adjusted to deliver passive, active, or resistive rehabilitation. Experimental results demonstrate that the proposed AAN controller can provide the total solution to cover each stage of wrist spatial-motion rehabilitation.

Event-Triggered Adaptive Hybrid Torque-Position Control (ET-AHTPC) for Robot-Assisted Ankle Rehabilitation

“…Thus critic NN is employed to approximate the optimal solution of 𝒬(𝑥), 𝜇 𝑠 and 𝛿 𝑒 . Based on Weierstrass high-order approximation, the approximation of 𝒬(𝑥) and 𝒬 ̃(𝑥) are 𝒬(𝑥) = 𝜔 𝑐 𝑇 𝜎 𝑐 (𝑥) + 𝜖 𝑐 (33) 𝒬 ̃(𝑥) = ∇𝜎 𝑐 𝑇 (𝑥)𝜔 𝑐 + ∇𝜖 𝑐 (34) where 𝜔 𝑐 denotes the ideal weight vector, 𝜎 𝑐 (𝑥) is the activation function, and 𝜖 𝑐 represents the approximated error of the critic NN. And assume that ‖𝜔 𝑐 ‖ ≤ 𝜔 𝑐𝑚𝑎𝑥 , ‖𝜎 𝑐 ‖ ≤ 𝜎 𝑐𝑚𝑎𝑥 , and ‖𝜖 𝑐 ‖ ≤ 𝜖 𝑐𝑚𝑎𝑥 .…”

Torque-Sensorless Control of Stepper Motors for Low-Cost Compliant Motion Generation

“…The stepper Figs. [13][14] show the angular displacement θ a of the output and the measured output torque τ a when the amplitude of oscillation from the external motor is 20°. Viscous damping compensation is used in Fig.…”

“…On the other hand, the torque control bandwidth would be smaller than actuators that use torque sensors. Hence series elastic actuators are more suitable in applications [12][13][14] where torque control accuracy is more important than torque control bandwidth.…”

Robust Region Tracking Control for a Robot Manipulator

“…Another example would be the robot assisted rehabilitation, which involves the passive and active phases, the robot would assist the movement of the patient during the passive rehabilitation phase, helping the patient reaching the active rehabilitation region. In the active rehabilitation region, the compliant behavior is desired as the patient takes initiative to accomplish the rest of the work [30], [31]. The concept of region reaching control for robot manipulator is originally proposed in [32].…”