Analysis and experimental study of non-holonomic mobile manipulator in presence of obstacles for moving boundary condition

In this paper a general formulation as well as experimental studies for finding Maximum Allowable Dynamic Load (MADL) of non-holonomic Wheeled Mobile Manipulator (WMM) in presence of obstacle and moving boundary condition is presented. Full dynamic model of wheeled mobile base and mounted manipulator is considered with respect to the dynamic of non-holonomic constraint and optimality conditions for carrying maximum payload between start point and moving end boundary in an environment including obstacle is derived. Obstacle avoidance is presented in terms of distance between colliding parts. The problem is formulated using Pontryagin’s minimum principle which leads to a two-point boundary value problem. An iterative algorithm is proposed by considering motor restrictions in terms of torque and jerk along the trajectory. The latest term ensures that the resulting trajectory is smooth enough. Also we proposed an algorithm for finding the maximum allowable dynamic load in moving boundary condition. It is a set of points which have no superiority on each other. This can be used for conditions in which robot is cooperating with conveyer belt. Simulation tests on a two-link planner non-holonomic WMM are done. To verify the effectiveness of the algorithm, the proposed approaches are illustrated using simulations and experimental studies of a two-link Scout WMM.