Modular Robot Manipulators with Preloadable Modules

While versatility and flexibility make modular and reconfigurable robots particularly suitable for applications in unstructured environments, the use of embedded electronics and local computers imposes an inherent limitation on control performance and payload capability. The virtual decomposition control (VDC) supported with a high-speed communication system has been suggested to effectively handle the dynamics and control issues aimed at allowing modular and reconfigurable robots to have the same control performance as integrated robots. In this paper, the payload capability issue is addressed by using a preloaded torsional spring to counter-balance static torques caused by gravity. Brief concept on spring design is presented, together with a review on system structure, communication mechanism, and VDC algorithms.