Patent ID: 7782006

Claim:
A motor controlling device comprising: a direct-current power supply; N H bridge circuits for N phase armatures of an alternating-current motor, wherein each H bridge circuit is provided between the direct-current power supply and each phase armature of the alternating-current motor, and comprises a first switching element configured to connect and disconnect a high potential end of the direct-current power supply to and from one end of the armature, a second switching element configured to connect and disconnect a low potential end of the direct-current power supply to and from the other end of the armature, a third switching element configured to connect and disconnect the high potential end of the direct-current power supply to and from said other end of the armature, and a fourth switching element configured to connect and disconnect the low potential end of the direct-current power supply to and from said one end of the armature; and an energization control unit configured to control the operation of said first to fourth switching elements of each H bridge circuit, thereby controlling the amount of energization of each armature, wherein said energization control unit is configured to control the amount of energization of each armature by a PWM control that involves changing a ratio, in a predetermined control cycle, between an energization control period, in which said first and second switching elements are turned on and said third and fourth switching elements are turned off in the associated H bridge circuit, or said third and fourth switching element are turned on and said first and second switching elements are turned off in the associated H bridge circuit, and a non-energization control period, in which said first and third switching elements are turned on and said second and fourth switching elements are turned off in the associated H bridge circuit, or said second and fourth switching elements are turned on and said first and third switching elements are turned off in the associated H bridge circuit, and wherein said alternating-current motor is a joint motor for a leg of a legged walking robot, and the motor controlling device is housed in a housing of the legged walking robot along with the joint motor.