Dynamic simulation model for mixed-loop planar robots with flexible joint drives

A dynamic simulation model for mixed-loop planar robots with flexible joint drive and servo-motor control is developed. The motion of the links is coupled with the deflection of the drive shaft at the joints. The virtual work method is used for the derivation of the mathematical model. The drive signal at the motor is based on the error between the desired and actual motions using proper position and velocity gains. Different motion programs are considered in the simulation for the time histories of the angular displacements and velocities of the links and motors. The driving torques and the total error produced at the end-effector are computed. The simulation results for a five-link, three degrees of freedom manipulator show that the model presented is capable of simulating the coupling effect of joint flexibility and rigid body motion for planar robots.