Method of controlling vibration motor

摘要

Provided is a method of controlling a vibration motor, in which there are provided: a unit that generates a drive signal for generating elliptic motion; a unit that switches the drive signal with a voltage from a power supply, and changes a pulse width of the drive signal; a unit that detects a current flowing in an electromechanical energy conversion element through the switching unit; a unit that detects a position and a velocity of an object to be driven; and a control unit that controls the respective units, and sets the velocity of the object to be driven. The control unit controls a frequency and the pulse width of the drive signal so as to exercise a maximum output characteristic with respect to a target velocity within a range in which the current detected by the current detection unit does not exceed a given limit value.

主权项

1. A method of controlling a vibration motor comprising an electromechanical energy conversion element joined to an elastic body, the method comprising:
generating a drive signal in accordance with a signal from a control unit; switching, using a switching unit, a voltage from a power supply in accordance with the drive signal; detecting a current flowing to the switching unit; detecting at least one of a position and a velocity of an object in contact with the elastic body of the vibration motor; determining whether a frequency of the drive signal is in a first frequency domain or in a second frequency domain; and performing at least one of narrowing of a pulse width of the drive signal and decreasing the frequency of the drive signal when the frequency of the drive signal is in the first frequency domain; and performing narrowing of the pulse width of the drive signal when the frequency of the drive signal is in the second frequency domain, wherein, in the first frequency domain, the current decreases when the frequency of the drive signal decreases, and wherein, in the second frequency domain, the current increases when the frequency of the drive signal decreases.