Identification of physically consistent dynamics parameter of the ABB IRB 360-6/1600 delta robot and its use for time-optimal motion planning under consideration of constraint forces

摘要

Model-based control schemes, forward dynamics simulations, constraint force computation and time-optimal motion planning have one major thing in common, they all depend on the dynamics parameters of the system. Physical consistency of the dynamics parameters ensures a positive definite mass matrix and correct constraint forces. The most common inverse dynamics identification method – the base-parameters – lack physical consistency. This paper proposes an identification method to identify physically consistent dynamics parameters for Delta-like robots while further showing the effects of friction in passive joints. A tailored model to compute the crucial constraint forces appearing in the mechanism based on the identified dynamics parameters is derived. This model is used to additionally consider constraint forces besides actuation torques for time-optimal motion planning of a typical pick and place task. This is done without any prior CAD data of the robot from the manufacturer. • Analytic, closed form modeling of a 4 degree of freedom Delta robot (parallel robot). • Physically consistent dynamics parameters identification method ensuring e.g. a consistent mass matrix for dynamics simulation. • Reduced dynamics model accounting for essential joint reaction forces and actuation torques. • Time-optimal motion planning considering both joint reaction forces and actuation torques demonstrated with a pick and place task.