Title
Position Based Impedance Control Strategy For A Lower Limb Rehabilitation Robot
Abstract
Active rehabilitation training can improve patients' neural engagement and the rehabilitation effects. A position based impedance control strategy is proposed for implement of active training in this paper. Firstly, it is necessary to accurately estimate patients' active torques during the training process, which can be calculated by using the human-robot dynamic model. A novel friction model is designed, where the influence of the joint coupling factor and viscosity is considered to improve the model accuracy. In order to prevent sudden changes of the interaction force, a virtual tunnel around the reference trajectory is established to limit the motion range to ensure patient safety in case of emergency, such as muscle spasm. Then, a position based impedance control strategy designed in the joint space is used to convert human torques into the required movement. The strategy is implemented by a double closed loop control structure, the outer loop of which converts the interaction force into angular, angular velocity, and angular acceleration deviations by the inverse impedance equation. The regulated trajectory will be used as reference for the inner position control loop. The experimental results show that the proposed system dynamic model can be used to accurately estimate the patients' active torques, and the proposed control strategy can be used to design a compliant human-robot interaction interface, so that patients can complete the training task comfortably and naturally, and also safety of the training can be ensured.
Year
DOI
Venue
2019
10.1109/EMBC.2019.8857186
2019 41ST ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)
Field
DocType
Volume
Coupling,Torque,Angular velocity,Control theory,Computer science,Electronic engineering,Angular acceleration,Impedance control,Control system,Robot,Trajectory
Conference
2019
ISSN
Citations 
PageRank 
1557-170X
0
0.34
References 
Authors
0
8
Name
Order
Citations
PageRank
Xu Liang110.72
Weiqun Wang22512.73
Zeng-Guang Hou32293167.18
Shixin Ren403.38
Jiaxing Wang500.34
Weiguo Shi602.03
Liang Peng72612.81
Tingting Su801.35