Design and implementation of a 7-DOF cable-driven serial spray-painting robot with motion-decoupling mechanisms

This paper presents the design and implementation of a 7-DOF cable-driven serial spray-painting robot (CDSSR) featuring motion-decoupling mechanisms and introduces an improved nonsingular inverse kinematics method for redundant serial robots. In the study, first, the motioncoupling characteristics of cable-driven joints and motion-decoupling methods based on translational and rotational compensation were examined. Next, the mechanical structure of the CDSSR was designed, including motion-decoupling mechanisms, cable-driven differential wrists, and tension-amplification mechanisms. In addition, an improved non-singular inverse kinematics approach incorporating dual-arm angles and configuration control parameters was developed. Finally, an experimentally scaled prototype of the proposed robot was constructed, and motion decoupling and spray trajectory planning experiments were conducted. The experimental and simulation results demonstrate the effectiveness of the non-singular inverse kinematics method in achieving efficient inverse kinematics solutions under global configuration control. Furthermore, the motion decoupling mechanisms designed for the serial robot successfully accomplished motion decoupling.