Vibration suppression of collaborative robot based on modified trajectory planning

Abstract

Purpose The paper aims to reduce the low-frequency resonance and residual vibration of the robot during the operation, improve the working accuracy and efficiency. A reduced weight and large load-to-weight ratio can improve the practical application of a collaborative robot. However, flexibility caused by the reduced weight and large load-to-weight ratio leads to low-frequency resonance and residual vibration during the operation of the robot, which reduces the working accuracy and efficiency. The vibrations of the collaborative robot are suppressed using a modified trajectory-planning method. Design/methodology/approach A rigid-flexible coupling dynamics model of the collaborative robot is established using the finite element and Lagrange methods, and the vibration equation of the robot is derived. Trajectory planning is performed with the excitation force as the optimization objective, and the trajectory planning method is modified to reduce the vibration of the collaborative robot and ensure the precision of the robot terminal. Findings The vibration amplitude is reduced by 80%. The maximum torque amplitude of the joint before the vibration suppression reaches 50 N·m. After vibration suppression, the maximum torque amplitude of the joint is 10 N·m, and the resonance phenomenon is eliminated during the operation process. Consequently, the effectiveness of the modified trajectory planning method is verified, where the vibration and residual vibration in the movement of the collaborative robot are significantly reduced, and the positioning accuracy and working efficiency of the robot are improved. Originality/value This method can greatly reduce the vibration and residual vibration of the collaborative robot, improve the positioning accuracy and work efficiency and promote the rapid application and development of collaborative robots in the industrial and service fields.

Development of a Human–Robot Interface for Cobot Trajectory Planning Using Mixed Reality

“…On the one hand, this work is often tedious due to the inertia and uncontrolled movements of the cobot's joints [3]. Furthermore, this practice is nuanced as hand-guidance is influenced by the dimensions and weight of the cobots [4]. On the other hand, operators must have specific knowledge of how to operate the teach pendant.…”

Research on Vibration Suppression Methods for Industrial Robot Time-Lag Filtering

“…The effectiveness of this method was experimentally verified on a Staubli RX90CR robot (Staubli, Pfäffikon, Switzerland), where the residual vibration of the robot during heavy motions was reduced by more than 85%. The literature [7] presents an enhanced trajectory planning method to reduce vibration in collaborative robots. The authors established a rigid-flexible coupled dynamics model of the robot using the finite element and Lagrangian methods and derived the vibration equations.…”

Command smoothing-proxy sliding mode control of hydraulic servo system considering structural flexibility

“…Therefore, how to remove the part of flexible structure in the design of closed-loop controller and realize vibration reduction on the basis of considering their characteristics is worth investigating. In Tian et al, 13 trajectory planning is performed with the excitation force as the optimization objective, and the trajectory planning method is modified to reduce the vibration of the collaborative robot and ensure the precision of the robot terminal. Besides, trajectory planning based on dynamic analysis and virtual control force are demonstrated and validated in Shi et al 14 and Lei et al 15 respectively.…”