A Leader-Follower Trajectory Planning Approach for Cooperative Robotic System in Automated Fiber Placement

The trajectory planning of cooperative robotic system for automated fiber placement (AFP) is a crucial topic since it has significant influence on the quality of the final products. This paper proposes a novel leader-follower trajectory planning approach for a 13-DOF (degree of freedom) cooperative robotic system in AFP. A 6-DOF serial robot holding the fiber placement head works as the leader, a 6-RSS (Revolute-Spherical-Spherical) parallel robot with a 1-DOF rotary stage holding the Y-shape mandrel works as the follower. Given a predefined fiber path with the desired angle 0°, an optimal trajectory planning method is developed for the serial robot subject to the kinematic and dynamic constraints. A cost function is established to guarantee the smoothness of the planned trajectory. Under this circumstance, the path of the fiber placement head may be deviated from the desired fiber path. According to the geometric constraint of AFP, namely, the direction of the roller in the fiber placement head should keep perpendicular to the mandrel surface, a vision-based trajectory generation strategy is designed for the parallel robot. Based on the desired trajectory of a defined point on the mandrel, the desired end-effector trajectory of the parallel robot can be determined using the visual measurement results. It can compensate the motion of the serial robot and ensure that the fiber is placed along the desired path. Simulation has been conducted to demonstrate the feasibility of the proposed leader-follower trajectory planning approach.