Abstract: A motor drive apparatus of an electric forklift includes first and second torque command value generation units that individually generate a torque command value indicating torque of a corresponding traveling motor in response to a gap between a speed command value and a speed detection value; and first and second slip detectors that individually generate a slip ratio estimation value showing a slip state of a corresponding drive wheel based on the speed detection value and the torque command value. The slip detectors individually have a first arithmetic unit which generates an inertial force estimation value proportional to a differential value of the speed detection value of the corresponding traveling motor and a second arithmetic unit which generates the slip ratio estimation value in response to a relationship between the corresponding inertial force estimation value and the torque command value of the corresponding traveling motor.

Abstract: A motor drive apparatus of an electric forklift includes first and second torque command value generation units that individually generate a torque command value indicating torque of a corresponding traveling motor in response to a gap between a speed command value and a speed detection value; and first and second slip detectors that individually generate a slip ratio estimation value showing a slip state of a corresponding drive wheel based on the speed detection value and the torque command value. The slip detectors individually have a first arithmetic unit which generates an inertial force estimation value proportional to a differential value of the speed detection value of the corresponding traveling motor and a second arithmetic unit which generates the slip ratio estimation value in response to a relationship between the corresponding inertial force estimation value and the torque command value of the corresponding traveling motor.

Abstract: According to one aspect of the invention, there is provided a sensor device which is capable of detecting a state of a movable stage using an easily manufacturable reference grating and capable of improving the accuracy of detection. The sensor device comprises a reference grating which has a configuration that is varied periodically in a two-dimensional direction. A light source emits light to the reference grating. A spectral unit has a plurality of openings to convert the light emitted by the light source into a plurality of light beams through the plurality of openings. A detector unit has a photodetector to receive collectively reflected light beams reflected by the reference grating. The detector unit is provided to detect a state of a movable body relative to the reference grating based on a change of the reflected light beams received by the photodetector.

Abstract: A position control device of a moving body, by which position control device a moving body can be driven in a translational manner with high precision where the moving body is not rotated in a yawing direction even if disturbance is input, a stage device using the position control device, and a position control method of a moving body, is provided.

Abstract: A position control device of a moving body, by which position control device a moving body can be driven in a translational manner with high precision where the moving body is not rotated in a yawing direction even if disturbance is input, a stage device using the position control device, and a position control method of a moving body, is provided.

Abstract: According to one aspect of the invention, there is provided a sensor device which is capable of detecting a state of a movable stage using an easily manufacturable reference grating and capable of improving the accuracy of detection. The sensor device comprises a reference grating which has a configuration that is varied periodically in a two-dimensional direction. A light source emits light to the reference grating. A spectral unit has a plurality of openings to convert the light emitted by the light source into a plurality of light beams through the plurality of openings. A detector unit has a photodetector to receive collectively reflected light beams reflected by the reference grating. The detector unit is provided to detect a state of a movable body relative to the reference grating based on a change of the reflected light beams received by the photodetector.