Collision-free path planning of a novel reconfigurable mobile parallel mechanism

This paper initially deals with the design of a new customized reconfigurable mobile parallel mechanism. This mechanism is called "Taar Reconfigurable ParaMobile (TRPM)", consisting of three mobile robots as the main actuators. Then, the kinematics and path planning for this mechanism are represented. The newly proposed mechanism is expected to circumvent some shortcomings of inspection operation in unknown environments with unexpected changes in their workspace, e.g., in a water pipe with non-uniform section area. In this paper, "Artificial Potential Field (APF)" has been assumed to be the path planning algorithm and its resulting attractive and repulsive forces are only applied to the end-effector to generate the desired path. It is worth mentioning that the obstacle considered in this paper is a wedge which models an environment with non-uniform section area along the path travelled by the end-effector. The inverse kinematics of TRPM is then developed. As a novel parallel mechanism, TRPM yields a 3-DoF kinematic redundancy. Despite the fact that this redundancy is sometimes beneficial to control procedure, solving the inverse kinematics of the TRPM would be feasible only by adding some constraints. As a result, there will be a system of equations consisting of three kinematic equations and three auxiliary equations. Results from this study reveal that by applying APF as the path planning algorithm to TRPM, it is possible to track proper paths to reach the target.