A Novel Method for Trajectory Planning of Cooperative Mobile Manipulators

We design a two-stage scheme to consider trajectory planning problem of two mobile manipulators for cooperative transportation of a rigid body in presence of static obstacles. Within the first stage, regarding the static obstacles we develop a method that searches the workspace for the shortest possible path between start and goal configurations by constructing a graph on a portion of the configuration space that satisfies collision and closure constraints. The final stage is to calculate a sequence of time-optimal trajectories to go between consecutive points of the path regarding the nonholonomic constraints and the maximum allowed joint accelerations. This approach allows geometric constraints such as joint limits and closed-chain constraints along with the differential constraints such as nonholonomic velocity constraints and acceleration limits to be incorporated into the planning scheme. Simulation results illustrate the effectiveness of the proposed method.