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SCIENCE CHINA Information Sciences, Volume 60, Issue 7: 073201(2017) https://doi.org/10.1007/s11432-017-9076-9

Robot assisted rehabilitation of the arm after stroke: prototype design and clinical evaluation

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  • ReceivedJan 10, 2017
  • AcceptedApr 22, 2017
  • PublishedJun 12, 2017

Abstract

Robot assisted rehabilitation training is a promising tool for post-stroke patients' recovery, and some new challenges are imposed on robot design, control, and clinical evaluation. This paper presents a novel upper limb rehabilitation robot that can provide safe and compliant force feedbacks to the patientfor the benefits of its stiff and low-inertia parallel structure, highly backdrivable capstan-cable transmission, and impedance control method in the workspace. The “assist-as-needed" (AAN) clinical training principle is implemented through the “virtual tunnel" force field design, the “assistance threshold" strategy,as well as the virtual environment traininggames, and preliminary clinical results show its effectiveness for motor relearning for both acute and chronic stroke patients, especially for coordinated movements of shoulder and elbow.

  • Figure 1

    (Color online) Training scenario using CASIA-ARM, where the patient is directed to catch the moving objects in the virtual environment with the robot's assistance.

  • Figure 2

    (Color online) Demonstration of the human-robot system, where $M_1$ and $M_2$ are the robot's joint motors, and $S$ and $E$ denote the patient's shoulder and elbow joints, respectively.

  • Figure 3

    (Color online) Reflected force at the end-effector over the workspace, where the force feedback capabilities at 20 positions over the workspace are depicted by parallelograms.

  • Figure 4

    (Color online) Structure of the low level controller of CASIA-ARM, where the joint torques are regulated through inner motor current control loop, $K_t$ represents the motor torque constant, $q=(\theta_1, \theta_2)$ is the joint space variable, and $I_{m1}$ and $I_{m2}$ represent the motor currents.

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