Da Vinci research kit: PSM and MTM dynamic modelling

The DVRK is currently used by 26 research groups around the world [1]. The platform consists of two patient side manipulators (PSMs), one endoscopic manipulator and two master tool manipulators (MTMs). The Johns Hopkins University [2] provides a full ROS-based open controller of all the DVRK robotic arms. The controller allows position, velocity and current control and thus opens the way for developing and testing advanced control techniques. However, some control techniques, e.g. impedance-force control, realistic dynamic simulations and sensor-less strategies for collision detection or contact force estimation, requires an accurate knowledge of the robots dynamic models. The aim of this work is to derive a complete dynamic model of both the MTMs and the PSMs arms of the DVRK system and use state of the art methods to obtain accurate identification of the dynamic parameters. In the case of the DVRK robot the presence of a 1-DOF double parallelogram and a counterweight in the PSM, and of a 2DOF parallelogram in the MTM make the model complex and require a detailed discussion. A constrained optimization approach based on LMIs has been adopted to guarantee physical consistency of the dynamic parameters. The results of the experimental validation of the identified models are satisfactory, especially for the PSM, although they could be further improved.