Research on the method of force-locking and variable stiffness for continuum robot with the spinal-like configuration

To solve the shortcomings of low stiffness brought by the high flexibility of continuum, but the variable stiffness method based on structure and phase change material has the problems of slow response and complex system, this paper takes the rope-driven flexible robotic arm as the research object, and proposes the design of spine-like continuum robot with force-locking variable stiffness arranged in the axial position, and investigates the performance of its variable stiffness. A reasonable structural design of the robot is obtained through bionic design and optimization of the bending structure. The theory's feasibility is analyzed based on tribology, and its variable stiffness system is simulated. The three joints and six degrees of freedom prototype are completed. Three experiments show that the method is fast responding, the stiffness of the robot is only controlled by adding an extra rope on the axis, and the structure is simple; and the comparison of the two configurations yields a continuum-raised robot configuration that is more suitable for the variable stiffness method proposed in this paper; and finally, the high flexibility is verified, and the relationship between stiffness and load and accuracy is verified. The research results make progress in the miniaturization, simplicity, and real-time performance of the variable stiffness method for continuum robots, which are helpful in the design of continuum robot configurations.