Design of Continuous Backbone, Cable-Driven Robots

Continuous backbone robots driven by cables have many potential applications in dexterous manipulation for manufacturing and space environments. Design of these robots requires specification of a stiff yet bendable backbone, selection of cable support heights and spacings, and development of a cable drive system. The robot arm divides into sections that are subdivided into segments bounded by cable supports. Cable pairs attach to the end of each section and provide two axis bending. Thus, with many sections, the arm can be bent into complex shapes to allow redundant positioning of the end effector payload. The kinematics of the entire arm are determined from the segment kinematics. This paper derives and numerically solves the nonlinear kinematics for a single segment of a continuous backbone robot. Optimal spacing of the cable supports maximizes displacement, load capacity, and simplicity of the robot kinematics. An experimental system verifies the theoretically predicted performance.