US Patent 11755113 Non-linear control of reluctance haptic engine

Embodiments are disclosed for non-linear control of a reluctance haptic actuator. A linear state feedback controller receives estimated position and velocity of a moving mass in a reluctance haptic engine and a reference position and velocity, generates a control signal based on the reference position and velocity and the estimated position and velocity. In response to the control signal, the drive electronics adjusts a current into at least one coil in the reluctance haptic engine to generate at least one magnetic field to control the moving mass. A non-linear state observer receives measurements of the voltage input into the reluctance haptic engine, the current, and an output voltage from a magnetic field sensor, and generates the estimated position and velocity of the moving mass based at least in part on the inputs, and sends the estimated position and velocity to the linear state feedback controller.