Linear resonant actuator, control system and brake control method

A control system for a linear resonant actuator, applicable to a linear resonant actuator having an induction coil for sensing vibration speed of the linear resonant actuator, the control system comprising:

• a signal amplifier, for amplifying an induced voltage of the induction coil of the linear resonant actuator into an induction signal;
• an excitation device, for generating an excitation signal able to cause the linear resonant actuator to vibrate;
• a flow controller, for receiving a command, generating a control flow, and outputting a state signal corresponding to the control flow;
• a processing unit, connected to the signal amplifier, the excitation device, and the flow controller, according to the state signal outputted by the flow controller, for stopping outputting in a stop state, outputting the excitation signal in an excitation state, and processing the induction signal into a braking signal of a suitable system damping coefficient and outputting as a driving signal;
• and
• a driver, connected to the processing unit and the linear resonant actuator, for driving the linear resonant actuator according to the driving signal outputted by the processing unit.

A brake control method for a linear resonant actuator, comprising the following steps:

• providing an induction coil, the induction coil being disposed outside a vibrator of the linear resonant actuator, and the induction coil being fixed with respect to the vibrator, wherein the arrangement of the position and winding manner of the induction coil able to obtain an induced voltage proportional to vibration speed of the vibrator;
• according to the induced voltage, generating a damping effect by a feedback approach to achieve controlling braking linear resonant actuator;
• wherein the damping effect satisfying the following conditions:
• according to the motion equation m*a=−b*v−k*x+f;
• wherein m is the mass of the vibrator, b is the actuator damping coefficient, k is the spring constant, a is the acceleration, v is the speed, and x is the displacement, f is the driving force;
• and k*x is the displacement restoring force, b*v is the damping force;
• let f=−b′*v denote the equivalent damping force to be generated by the driving coil, wherein b′ is the damping coefficient for braking;
• the above motion equation becomes:
• m*a=−(b′+b)*v−k*x;
• wherein −(b′+b)*v is damping force under the effect of the brake control method, which is the target damping effect to be generated.