A Novel Driving Pattern to Actualize Haptic Effects in Mobile Devices

Haptic interactions in consumer devices have become more critical with immersive streaming content by including high-resolution video and sound as well as tactile information. Mobile devices such as tablets and smartphones are significantly limited for creating effective haptic illusions as they are too small in size to accommodate complex actuators and are without mechanical support. Recent studies and commercial products show that the use of larger and complex multi-coil linear resonant actuators (LRAs) can significantly improve tactile perception quality at the expense of significant design constraints such as size and cost. In this study, a novel driving pattern and complete system design are presented that enables similar quality haptic effects using a simple LRA system. The proposed driving pattern consists of segmented signals with different frequencies and duty cycles determined from finite element-based modal analysis, and it was used to simulate the two most common touch controls, the button and slider, on a mobile device. Numerical and experimental results showed that the system can achieve a 3× reduction in cost, a 9× reduction in weight, and a 6× reduction in volume. User tests comparing smartphones with the novel LRA driving pattern and the benchmark devices demonstrated the feasibility of a low-cost solution to improve haptic effects and illusions.