Wire-driven waist rehabilitation training robot (WDWRTR): mechanical design, sliding mode variable structure control and experimental validation

Purpose To enhance the efficacy of rehabilitation training for patients with waist disorders, this study aims to develop a wire-driven waist rehabilitation training robot (WDWRTR), proposes intelligent control strategies and experimentally validates the functionalities of the WDWRTR. Design/methodology/approach The mechanical design of the WDWRTR accounts for rehabilitation movement patterns and tackles the issue of wire interference. To address the motion coupling problem in the wire traction mechanism, the kinematic model was established using two coordinate systems and the model was constructed using the Newton–Euler method. Due to the dynamic configuration of the WDWRTR, a sliding mode variable structure control method with continuous switching was proposed and its stability was analyzed. Both simulation and prototype experiments were conducted using left and right lateral bending of the waist as examples in this study. Findings The simulation outputs of wire length and tension were consistent with prototype measurements, and the actual trajectory of the scaled model closely matched the preset trajectory. Prototype experiments also validated multiple WDWRTR functions, including information communication, data acquisition and human–machine interaction. The developed prototype can perform the lateral bending movements required for waist rehabilitation training. Overall, the results demonstrate the effectiveness of the proposed control method. Originality/value This study highlights the scientific significance and reference value of the WDWRTR in flexible rehabilitation robot research by providing valuable evidence for subsequent structural optimization and control algorithm iterations.