This paper investigates the application of a pendulum model in designing and simulating a 5-DOF robotic system that transports an open-top container filled with liquid free of any spill. In this work, the robot consists of a 3-DOF robotic arm for positioning and a 2-DOF end-effector for adjusting the containers orientation to prevent spillage. The system is implemented using both Matlab Simulink and Simscape environment. In this hybrid setup, Simscape handles the robots kinematic modeling, while Simulink is used for controlling the end-effectors orientation with a PID controller. Under the pendulum model, the gripper, the open-top container and the liquid move as one mass along the pendulum trajectory, so that no liquid is spilled out during the movement. Results indicate trajectory tracking accuracy. This approach avoids the need for complicated computational fluid dynamics model and underscores the advantages of autonomous mobile robots in achieving reliable performance in spill-free liquid handling, a task difficult to achieve for human beings.
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