Trajectory planning for cable robot with pneumatic cylinder integration: direct collocation method

Abstract Direct collocation (DC) methods are utilized for addressing trajectory optimization challenges in robotics due to their ability to generate dynamically consistent solutions. However, in the cable-driven robotic systems, where tension constraints impose kinodynamic restrictions, maintaining accuracy becomes significantly complex. This article addresses robot tensionability and proposes a method to overcome the limitations. A DC method is proposed to minimize the actuator force rate in a trajectory planning problem for a designed cable-driven parallel robot. The system comprises a 3-cable parallel mechanism with a central spine to counteract the end-effector’s weight and enhance tensionability. Integrating a pneumatic cylinder into the system that supports trajectory planning implementation is essential to minimize jerky motions. The DC method is applied through the proposed quadratic programming approach and benchmarked against existing packages to achieve and compare the resulting smoother trajectory. The numerical results demonstrate that the proposed method significantly reduces computation cost and enhances accuracy. Experimental data corroborate the simulation results, validating the method’s efficacy.