Dynamic Modeling and Adaptive Control of Cable-Driven Redundant Manipulator

Abstract

A cable-driven redundant manipulator (CDRM) characterized by redundant degrees of freedom and a lightweight, slender design can perform tasks in confined and restricted spaces efficiently. However, the complex multistage coupling between drive cables and passive joints in CDRM leads to a challenging dynamic model with difficult parameter identification, complicating the efforts to achieve accurate modeling and control. To address these challenges, this paper proposes a dynamic modeling and adaptive control approach tailored for CDRM systems. A multilevel kinematic model of the cable-driven redundant manipulator is presented, and a screw theory is employed to represent the cable tension and cable contact forces as spatial wrenches, which are equivalently mapped to joint torque using the principle of virtual work. This approach simplifies the mapping process while maintaining the integrity of the dynamic model. A recursive method is used to compute cable tension section-by-section for enhancing the efficiency of inverse dynamics calculations and meeting the high-frequency demands of the controller, thereby avoiding large matrix operations. An adaptive control method is proposed building on this foundation, which involves the design of a dynamic parameter adaptive controller in the joint space to simplify the linearization process of the dynamic equations along with a closed-loop controller that incorporates motor parameters in the driving space. This approach improves the control accuracy and dynamic performance of the CDRM under dynamic uncertainties. The accuracy and computational efficiency of the dynamic model are validated through simulations, and the effectiveness of the proposed control method is demonstrated through control tests. This paper presents a dynamic modeling and adaptive control approach for CDRM to enhance accuracy and performance under dynamic uncertainties.