Patent ID: 8471512

Claim:
A robotic device comprising: an arm; a motor that moves the arm and that has a magnetic coil; and a motor control circuit that controls the motor, the motor control circuit comprising: a driver circuit having a switching element that turns on/off a connection between the magnetic coil and a supply voltage supplied from an external power supply, thereby intermittently supplying the supply voltage to the magnetic coil; a switching signal generating circuit that generates a switching signal for use in on/off control of the switching element; and a supply voltage setter that supplies the switching signal generating circuit with a supply voltage control value which is related to the supply voltage, wherein the switching signal generating circuit adjusts an effective voltage applied to the magnetic coil by adjusting a pulse width of the switching signal according to the supply voltage control value such that the effective voltage applied to the magnetic coil assumes a prescribed constant value irrespective of the value of the supply voltage, and the switching signal generating circuit includes a waveform signal generator that generates a waveform signal which exhibits a periodic change in wave shape and which has amplitude inversely proportional to the value of the supply voltage, and a PWM control circuit that executes PWM control based on the waveform signal to generate the switching signal which exhibits change in effective value equivalent to the change of the waveform signal.