Smooth swing trajectory and posture planning simulation of small gantry welding robot end based on NURBS curves

In this paper, a swing welding trajectory planning algorithm was proposed for the welding tasks such as frames and doors in the air-raid shelters. Firstly, through manually calibrating the worktable position and the welding starting point under world coordinate system, the basic welding trajectory planning plane was calculated, which established the swing welding model with core parameters such as the tilt angle, the swing amplitude, and the swing angle. Secondly, to ensure continuous position, velocity and acceleration at the welding end, employing NURBS curve for inverse interpolation fitting with accumulating chord length parametrization method, the mathematical model of position and attitude synchronization description was established based on positional parameters. Simulation experiments show that the proposed planning method can generate smooth trajectories with uniformity and continuous velocity, which meets the requirements of welding applications.