Compliant control for wearable exoskeleton robot based on human inverse kinematics

Abstract

Rehabilitation robots are a new technology dedicated to the physiotherapy and assistance motion and has aroused great interest in the scientific community. These kinds of robots have shown a high potential in limiting the patient’s disability, increasing its functional movements and helping him/her in daily living activities. This technology is still an emerging area and suffers from many challenges like compliance control and human–robot collaboration. The main challenge addressed in this research is to ensure that the exoskeleton robot provides an appropriate compliance control that allows it to interact perfectly with humans. This article investigates a new compliant control based on a second-order sliding mode with adaptive-gain incorporating time delay estimation. The control uses human inverse kinematics to complete active rehabilitation protocols for an exoskeleton robot with unknown dynamics and unforeseen disturbances. The stability analysis is formulated and demonstrated based on Lyapunov function. An experimental physiotherapy session with three healthy subjects was set up to test the effectiveness of the proposed control, using virtual reality environment.

A Novel Modified Super-Twisting Control Augmented Feedback Linearization for Wearable Robotic Systems Using Time Delay Estimation

“…The system is equipped with a virtual interface, for which patients and therapists can track the progress of the rehabilitation exercises. The interface can further provide task-oriented exercises in joint space and Cartesian space [ 28 ]. The Denavit-Hartenberg (DH) parameters and workspace of the robot are given in Appendix A.3 .…”

Design and evaluation of a surface electromyography-controlled lightweight upper arm exoskeleton rehabilitation robot

“…There are nine sets of data under one weight value in one channel, which are labeled as 1 to 9 according to the order stored in the matrix. By the Randi number, the following features of elements in the testing set can be obtained, channel number (1-8), weight (0 kg, 2 kg, 4 kg, and 6 kg), and sequence number (1)(2)(3)(4)(5)(6)(7)(8)(9). The resulting elements from 288 times the process mentioned above are stored in the verification set.…”

“…Some exoskeleton robots with multiple joints in series have been developed for repetitive task training, with unlimited arm workspace in rehabilitation movement and good human-robot interaction performance. 7,8 Virtual reality is often introduced in the procedure to improve training duration and stimulation effect. With the assistance of the exoskeleton, the patient approaches or follows a target through the guidance of the scene.…”

Design and Development of an Upper Limb Rehabilitative Robot with Dual Functionality

“…This leverage over traditional therapy could increase the efficiency and effectiveness of therapists by alleviating the labor-intensive aspects of physical rehabilitation of post-stroke patients [ 3 ]. To provide rehabilitation therapy to individuals with upper limb impairment, several research prototypes have been developed to date [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Among these prototypes, very few were transferred into a commercial product, as they have limitations (in both hardware and control design), which are discussed in following paragraphs.…”

“…Such an oversight can become costly if the wearer has a stiff arm. Furthermore, current rehab devices have ignored measuring interaction forces at the wearer’s upper arm [ 6 , 41 , 42 ]. To measure the interaction forces at the upper arm, a sensorized upper arm cuff was designed and developed for u-Rob’s upper arm module.…”