Hybrid passive vibration control of lightweight manipulators

Passive vibration control methods in the literature are known to be highly sensitive to dynamic system parameters and are generally applied one by one. Therefore, their effectiveness in suppressing vibration control is limited. In this work, hybrid passive control (HPC) by integrating the Posicast control (PC) and the motion parameters-based control (MPC) is developed to suppress the during-motion vibrations (DMV) and residual vibrations (RV) of a single-link lightweight manipulator with a payload. PC is designed as a three-step cycle using the first natural frequency and damping ratio of the manipulator. MPC is designed by determining the time parameters of the motion profiles based on the first natural frequency of the manipulator. HPC simulations are performed on MATLAB, creating a Simscape model of the manipulator. Then, the proposed control method is tested in experiments. The prepared hybrid motion inputs actuate the servomotor while the displacements are measured, using a laser sensor at the tip of the manipulator. DMV and RV responses and their RMS values reveal that suppressing the vibration amplitudes efficiently. MPC is mostly effective in eliminating RV, whereas PC is sensitive to DMV as well. HPC combines these methods by eliminating their disadvantages and highlighting their advantages. Moreover, it is also successful in cases where the deceleration time of the trapezoidal input signal is single times half of the natural period, unlike MPC.