Kinesthetic Haptic Actuators: A Comparative Study of Motor Technology

Abstract

This thesis evaluates a BLDC motor for use as a direct drive haptic actuator. This is done by a comparison of the performance and specifications of a direct drive BLDC motor with those a of the actuator used in a common haptic device, comprised of a DC motor and capstan mechanism. To facilitate this comparison, an experimental platform, consisting of the two actuators and all associated mechanical and electrical systems, was constructed. The actuators are compared using a variety of metrics, which were first calculated using time-domain, Laplace-domain, and discrete time models, as well as PSIM simulation. The comparison metrics were then determined experimentally and compared. These metrics include datasheet parameters, peak torque determined using a thermal simulation, current and position step responses, uncoupled stability regions, and rendering areas. Based on this comparison, it can be concluded that a direct drive BLDC motor offers both a higher peak and continuous torque, while having lower inertia and therefore higher acceleration than the DC motor and capstan. The DC motor and capstan is lighter than the BLDC motor, but has significantly more friction. Because on these differences, the BLDC motor has a larger rendering area than the DC motor and capstan, as well as a larger uncoupled stability region. These results indicate that BLDC motors are a promising technology for effective direct drive haptic actuation.