Enhancing Touch Control on the Steering Wheel with Force Input

Steering wheel controls have become an essential interface for interacting with in-car human machine interfaces. The increase in both number and complexity of features in the car challenges the scalability of button-based mechanical steering wheel interfaces. Alternatives such as touch input are making their way into steering wheels of mass production cars. Multi-level force input adds a degree of freedom for touch interaction and therefore increases the richness and expressiveness of touch interfaces. We propose to implement force input into steering wheels by using force sensitive touchpads. We explored multi-level force input on the steering wheel in an extensive controlled experiment. The results provide insights into the user sensory threshold in discriminating differences in force input on a steering wheel and its impact on design specifications for force sensing touchpads.