Parameter Estimation of a Gearless Pitch-Roll Wrist

The work reported here pertains to the design, modelling and analysis of a testbed for a Gearless Pitch-Roll Wrist (PRW), currently under development at McGill University’s Centre for Intelligent Machines. This work aims at the mechanical-parameter identification of the Spherical Epicyclic Cam Train (SECT) prototype of the PRW. The testbed is constructed and set-up, in order to conduct experiments designed to quantify mainly stiffness and damping of the PRW with the purpose of comparing its performance with that of commercial wrists. To this end, a data-acquisition system is installed and calibrated. A mathematical model of the testbed is formulated, based on which an analysis is carried out to determine that the modelled system as identifiable and controllable with its motion and torque sensors. Simulations are conducted using assumed values and are able to carefully estimate the testbed operation. Operational limits are also reported as damage to the testbed can be time-consuming and very costly to repair. Experiments and estimation of the mechanical parameters will be carried out as a second part of the project.