Development of haptic device for hinge mechanism based on motor-MR brake hybrid actuator

Abstract

Developing a haptic device is essential for delivering haptic feedback in virtual prototyping designs. Hinge mechanisms, commonly found in various household appliances, exhibit diverse torque range and work space, making the design of an appropriate haptic device crucial for influencing user experience. While several haptic devices simulating different hinge mechanisms like car doors, refrigerator doors, and washing machine doors have been proposed, many studies have attempted to implement them using only motors. However, attempting to replicate passive torques, which change direction based on rotation, solely with active actuators such as motors can lead to unnatural haptic sensations and, in extreme cases, instability. To address these issues, this thesis presents the development of a hybrid haptic device capable of controlling both active and passive actuators simultaneously. The research primarily focuses on implementing a car door mechanism that involves (1) interacting with users through high torques, (2) varying torque profiles depending on the open/close direction, and (3) experiencing combined effects of driving and resisting torques. To achieve these goals, a magneto-rheological fluid brake (MR Brake) was designed and manufactured as the passive actuator. Furthermore, we introduce a novel control technique designed to decompose the car door torque profile into distinct active and passive torque components, effectively distributing each to the motor and brake. Leveraging direct torque control and feedback control methods, we achieved simultaneous and precise control of both the motor and the Magneto-Rheological brake, ensuring an authentic and immersive haptic feedback experience. Through the synergy of our developed haptic device and this advanced control methodology, we quantitatively and qualitatively assessed the similarity to the haptic sensation of actual car door operation. The outcomes of our user evaluations lead us to a compelling conclusion: the proposed haptic device is capable of faithfully simulating the intricate car door mechanism, and users can effectively differentiate the operation of specific car door models.