Patent ID: 6422747
Filing Date: 2002-07-23
Classification: A61B

Abstract:
An X-ray photographing apparatus, comprising:a base for an X-ray photographing apparatus, an operation handle attached to the base, pressure sensors attached to the operation handle to be pressed by operation forces applied to the handle to thereby provide signals of the operation forces, a pair of driving wheels attached to the base to be driven individually, a pair of motors attached to the respective driving wheels for driving the wheels, bridge circuits electrically connected to the respective motors for driving the motors, each bridge circuit having a switching element and being arranged such that one of the motors is electrically placed at a center thereof, pulse width control circuits connected to the bridge circuits for controlling ON-OFF duty of torques of the respective motors, a pair of encoders for detecting rotational speeds of the wheels and issuing signals of the rotational speeds, and a central processing unit electrically connected to the bridge circuits and the pulse width control circuits for controlling the torques of the motors in accordance with the signal from the pressure sensors and the signals from the encoders to rotate the wheels for moving the X-ray photographing apparatus, said central processing unit controlling pulse width of the pulse width control circuit in proportion to a value calculated by a formula: {(a maximum value of a pulse control width)/(a maximum output torque of the motor)}Ã—{(a maximum rotational number of the motor)/(the maximum rotational number of the motorâˆ’a rotational number of the motor)}Ã—(a force for pushing the operation handle).