A Mechanism and Control Design of Flexible Spine driven by Pneumatic Artificial Muscles

In order to further improve the bionic characteristics of the quadruped robot and enhance its stability and flexibility of motion, in this paper, we designed a flexible spine driven by pneumatic artificial muscles (PAMs). Firstly, inspired by the Hooke's Joint, we complete the design of spinal mechanism with 2 rotational DOFs, which is driven by 4 parallel PAMs, and achieve feedback of posture by using 2 encoders fitted on sides. Furthermore, in order to enhance the mechanism's loading capacity, we adopt the X-shaped controlling layout of PAMs instead of cross-shaped controlling layout of that. Secondly, we use proportional-integral-derivative (PID) algorithm to control the spinal mechanism and tested its performance through tracking step, sine as well as central pattern generator (CPG) planning trajectories. Finally, we analyze experimental data and the results show that the tracking performance meet the predetermined requirements.