Apple Inc.

Juil Lee

Darya Amin-Shahidi

Hari Vasudevan

Denis G Chen

Riccardo Tarelli

Denis M Chen

Haptic power control techniques provide improved power control for the haptic generator to reduce deficiencies of operation and/or increase performance of the haptic generator across various thermal conditions. In some examples, a first resistance measurement can be obtained and used for estimating an actuation voltage limit for the haptic generator. In some examples, estimating the actuation voltage limit for the haptic generator using the first resistance measurement includes estimating a first actuation voltage limit for the haptic generator when the first resistance measurement is a first resistance value and estimating a second actuation voltage limit for the haptic generator when the first resistance measurement is a second resistance value.

Haptic power control techniques for haptic systems

Disclosed herein are reluctance actuators and methods for feedback control of their applied force. Embodiments of the reluctance actuators include an electromagnet positioned to deflect a metallic plate to provide a haptic output. The control of the force is provided without force sensors (sensorless control) by monitoring voltage and/or current (V/I) applied during an actuation. For a given intended force output, an electrical parameter value (flux, current, or other parameter) is read from a look up table (LUT). The LUT may store a present value of the inductance of the reluctance actuator. The feedback control may be a quasi-static control in which the LUT is updated after actuation based on the monitored V/I. The feedback control may be real-time, with a controller comparing an estimated electrical parameter value based on the measured V/I with the value from the LUT.

Methods to control force in reluctance actuators based on flux related parameters

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.

Non-linear control of reluctance haptic engine

A haptic system includes a haptic engine in which a reluctance motor is driven by a driver controller operated in conjunction with an impedance-estimator that uses amplitude-modulated calibration signals. An enveloped-calibration signal is superimposed on a haptic-drive signal to quickly, and accurately, estimate the driving coil's impedance, while minimizing power penalty.

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Pleasanton, CA, United States of America

Juil Lee