Dynamic deformation analysis of a spot welding robot under high speed and heavy load working condition

Abstract

As an important type of industrial manipulator, spot welding robots are usually needed to work under high speed and heavy load working condition. The working condition can cause a dynamic deformation of the robot, which cannot be fast and accurately calculated currently. The dynamic deformation leads to poor performance of the robot, e.g. the end effector trajectory deflection and vibration. In this paper, we present a method for the robot dynamic deformation calculation, which can be practically applied to spot welding robots. The method is mainly implemented in three steps: 1. Based on the robot working condition, we first calculate the kinestate of each link in base frame, i.e. angular velocity and acceleration, linear velocity and acceleration. And we thus can obtain the inertia forces and torques of each link. 2. We build a finite element analysis (FEA) modeling by confirming the robot configuration, defining material property, setting constraints and meshing. 3. Orderly, we apply each inertia fore, inertia torque, robot gravity and load on the FEA modeling and calculate the responding dynamic deformation. The total deformation can be obtained by sum of all deformations, and we can also get the stress and strain condition in the same way. The proposed method provides a basis for robot dynamic deformation calculation and its effectiveness has been demonstrated by experiments.