Effect of Cogging Force on Linear Haptic Motor

As consumer electronics evolve, precise tactile feedback via linear haptic motors (LHMs) has become crucial for enhancing user interaction in devices such as smartphones and gaming controllers.This study investigates the effect of cogging force on LHM performance.A theoretical model is developed using the Maxwell stress tensor to calculate electromagnetic force distributions.The force relationship has been derived to analyse the performance of LHM.Three experiments validate the effect of cogging force, which can be treated as a negative stiffness, reducing the mechanical stiffness of the system.A 4-magnet design is proposed to obtain a linear cogging force.An electromagnetic-mechanical (E-M) coupling model is used to obtain the displacement of LHM.The analysis result has a good agreement with experimental data.This work lays the groundwork for future LHM research.