Personal care appliance with self-adaptive amplitude regulation via actuator non-linearity and active driving adjustment and method thereof

Abstract

A personal care appliancecomprises an actuator, a current sensorfor monitoring a driving current, and a controller. The actuator, operable according to a non-linear response characteristicof amplitude versus frequency, includes a movable shaftconfigured for resonant movementin response to a drive signal, further for being coupled with a workpiece. The controller(i) detects at least one of a plurality of different characteristic load states () in response to a perturbation in the monitored driving currentand (ii) actively delivers the drive signalto the actuatorselected from at least two different drive signals () as a function of a detected characteristic load state. In this manner, the controllerimplements self-adaptive amplitude regulation of the movable shaft's resonant movementamong the plurality of difference characteristic load states that include additional loads of force, spring, mass, and/or damping to a given load state of a resonant spring mass system of actuatorcoupled with workpiece