Torque Tracking Control for Lower Exoskeleton Robot with Friction Compensation based on System Identification.

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Bibliographic Details
Title:	Torque Tracking Control for Lower Exoskeleton Robot with Friction Compensation based on System Identification.
Authors:	Liu, Fenggang¹ fg_liu1314@163.com, Zhan, Mingfang¹ 405575878@qq.com, Yu, Lie¹ 337293948@qq.com
Source:	IAENG International Journal of Applied Mathematics. Jul2026, Vol. 56 Issue 7, p2541-2550. 10p.
Subjects:	System identification, Least squares, Robust control, Robotic exoskeletons, Hydraulic servomechanisms
Abstract:	This study proposes an enhanced friction model based on the Dahl approach for exoskeleton robots driven by electro-hydraulic servo systems (EHSS). The model parameters are determined using a recursive least squares identification scheme. Experimental data are collected from sensors mounted on the exoskeleton robot. Encoders are used to measure the joint angle and velocity, while two pressure sensors installed in the EHSS measure the pressures in the head chamber and rod chamber. The friction force is directly computed from the dynamic equation at very low motion speeds. The system identification method with recursive least square is used to identify the parameters of Dahl model, and the best parameter gains are obtained through walking tests. Two control cases are examined, such as one without friction compensation and the other with friction compensation. The results show that friction compensation reduces tracking lag and mean absolute error, and improves overall control performance. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	This study proposes an enhanced friction model based on the Dahl approach for exoskeleton robots driven by electro-hydraulic servo systems (EHSS). The model parameters are determined using a recursive least squares identification scheme. Experimental data are collected from sensors mounted on the exoskeleton robot. Encoders are used to measure the joint angle and velocity, while two pressure sensors installed in the EHSS measure the pressures in the head chamber and rod chamber. The friction force is directly computed from the dynamic equation at very low motion speeds. The system identification method with recursive least square is used to identify the parameters of Dahl model, and the best parameter gains are obtained through walking tests. Two control cases are examined, such as one without friction compensation and the other with friction compensation. The results show that friction compensation reduces tracking lag and mean absolute error, and improves overall control performance. [ABSTRACT FROM AUTHOR]
ISSN:	19929978