ABSTRACT The Cobotic Hand Controller: Design, Control and Analysis of a Novel Haptic Display

Haptic displays utilizing cobotic technology are able to simulate virtual environ-ments with high dynamic range. The use of nonholonomic, continuously variable transmissions allows for extremely high stiffness in directions that would violate a virtual constraint. At the same time, smooth, unimpeded motion is permitted tan-gential to virtual constraints and in open space. This thesis introduces a novel six-degree-of-freedom cobot, utilizing six continu-ously variable rotational-to-linear transmissions connected in parallel to a common power cylinder. A controller is developed to best utilize the control freedom of this redundantly actuated cobot. Kinematics and dynamics of the Hand Controller are derived, along with extensive characterization of its overall control architecture and resulting performance. An admittance device framework for physically accurate hap-tic display of bilateral constraints and inertia is developed and examples provided. iii This thesis also provides an extensive analysis of the rotational-to-linear dry-friction rolling contact cobotic transmissions utilized in the Cobotic Hand Controller. The elastic, inelastic and shear losses at the contact patch are characterized and a bond graph is provided. In addition, losses due to overhead of the cobotic system are analyzed and a power efficiency comparison is made between cobotic and conventional system architectures. An understanding of the implications of cobotic transmission design on the performance of a high-degree-of-freedom haptic display is provided. i