Global Vibration Suppression of an Industrial Manipulator Through Trajectory Planning Based on Local Flexible Mode Identification

Fast motion and low vibration are often conflicting requirements in industrial robots. Due to joint flexibility, operating at high accelerations can excite mechanical resonance, leading to vibrations that may accelerate gearbox wear and degrade control performance. Effectively suppressing these vibrations requires accurate modeling, identification, and compensation of joint flexibility across the entire workspace and under various payloads. The conventional two-mass model, which focuses on joint rotational stiffness in the gearbox, fails to capture the global flexibility characteristics, as flexibility also arises from bending in the bearings. This article presents a practical multi-local-mode-based model and the corresponding identification method to globally characterize a manipulator’s joint flexibility. Based on this model, a vibration suppression method is developed to mitigate mechanical resonance, achieving low vibration even at high acceleration. Comparative experiments demonstrate that the proposed approach effectively suppresses vibrations across the workspace and under various payload conditions.