Evaluation of a Robust Haptic Interface for Semi-Autonomous Vehicles

The advent of steer-by-wire technologies has changed the driving paradigm for drivers and vehicle autonomy. Such technologies integrate electric motors to actuate the tire-road plus human-machine interfaces. Steer-by-wire vehicles can benefit from haptic concepts through the provision of tunable force feedback, coupled with nonlinear control, to introduce lane keeping and pathway following technologies that minimize and possibly eliminate driver actions. In this article, two vehicle haptic interfaces, including a robotic grip and a joystick, both of which are accompanied by nonlinear sliding mode control, have been developed and studied on a steer-by-wire platform integrated with a virtual reality driving environment. An operator-in-the-loop evaluation that included 30 human test subjects investigated these haptic steering interfaces over a prescribed series of driving maneuvers through real-time data logging and post-test questionnaires. A conventional steering wheel with the robust sliding mode controller was used for all the driving events for comparison. Subjective and objective results from the tests demonstrate that the driver’s experience can be enhanced by up to 76.3% with a robotic grip steering input when compared to the steering wheel during extreme maneuvers. The robotic grip’s superior performance in certain vehicle maneuvers indicates its potential as an alternative haptic steering adaptation for future semi-autonomous vehicles.