Passive haptics: greater impact presented by pulsive damping brake of DC motor and physical indices for perceived impact

This study investigated the perceptual characteristics of pulsive brakes presented by passive haptic interfaces. A passive-type haptic interface based on the damping brake of a DC motor was used to generate impact; this has merits of inherent safety and energy efficiency. This haptic interface expresses impacts by resisting the operator’s hand via the resistive force generated by a damping brake. In terms of impulse or momentum, maximum impact was achieved by continuously operating the damping brake after colliding with a virtual object. We found that instantaneous release of the brake immediately after collision increases the perceived impact. We computed several physical indices associated with the force against the hand as well as the hand velocity and investigated their relationships with the perceived magnitudes of the impacts. A high correlation was found between the absolute change ratio of the hand velocity and the perceived impact, which suggests that instantaneously releasing the brake is effective in terms of impact perception. Our findings indicate that the performance of passive haptic interfaces can extend physical limits, and the range of applications can be expanded by incorporating human perceptual characteristics.