A Novel Strut-Type Modular Robotic Structure Using Rigid Node

This paper proposes a novel way of constructing strut-type modular robotic structures to avoid some difficulties of designing and implementing ideal compliant nodes. Rigid nodes are employed to replace the ideal compliant nodes and to reduce the structural complexity while the feasibility of hardware implementation is dramatically improved. To release some kinematic constraints caused by the rigid nodes, we introduce robotic struts that consist of two prismatic actuators linked by a passive revolute joint. Physics-based robot models are constructed using a robot simulator. A scalable distributed control method is implemented using coupled central pattern generators. And, for comparison, the same control method is applied to conventional and the proposed strut-type modular robotic structures. Simulation results show that the proposed strut-type structures have several advantages over the conventional ones including less number of passive joints and shape-maintenance property.