Kinematics analysis of in-parallel 5 DOF haptic device

Parallel-architecture haptic devices offer significant advantages over serial-architecture counterparts in applications requiring high stiffness and high accuracy. To this end, many haptic devices have been created and deployed by modularly piecing together several serial-chain arms to form an in-parallel system. However, the overall system performance depends both on the nature of the individual arms as well as their interactions. We build on the rich theoretical background of constrained articulated mechanical systems to provide a systematic framework for formulation of system-level kinematic performance from individual-arm characteristics. Specifically, we develop the system-level kinematic model in a symbolic (yet algorithmic) fashion that facilitates: (i) computational development of pertinent symbolic equations; (ii) generalization to arbitrary architectures; and (iii) combined symbolic/numeric analyses of performance (workspace, singularities, design sensitivities). These various aspects are illustrated using the example of the Quanser High Definition Haptic Device (HD) 2 - an in-parallel haptic device formed by coupling two 3-link Phantom 1.5 type serial chain manipulators with appropriate passive joints. We also briefly discuss aspects of ongoing work for design-prototyping and validation, taking advantage of tools from Virtual Prototyping and Hardware-in-the-Loop testing.