Dynamic Simulation of a Flexible Robot Arm and Controller

High performance requirements in robotics have led to the consideration of structural flexibility in robot arms. This paper employs an assumed modes method to model the flexible motion of the last link of a spherical coordinate robot arm. This model is used to investigate relationships between the arm structural flexibility and a linear controller for the rigid body motion. This simple controller is used to simulate the controllers currently used in industrial robots. The simulation results illustrate the differences between leadscrew driven and unconstrained axes of the robot; they indicate the trade-off between speed and accuracy; and show potential instability mechanisms due to the interaction between the controller and the robot structural flexibility.