Abstract: A duty ratio control device includes a duty ratio calculation unit and a parameter setting unit. The duty ratio calculation unit, when an acceleration manipulation is performed, calculates a control duty ratio per predetermined timing based on a value of at least one parameter so that a rotation speed of a motor mounted on an electric power tool reaches a target rotation speed corresponding to the acceleration manipulation. The control duty ratio is calculated to be larger as the value of the at least one parameter is larger. The parameter setting unit sets the value of the at least one parameter. The value of the at least one parameter set for a reacceleration manipulation is larger than the value of the at least one parameter set for an initial acceleration manipulation.

Abstract: A speed controller for a small electric motor is described. The controller is used to control small electric motors such as those used in small power tools such as electric screwdrivers. A series of electrical components are used to allow the motor to remain idle until a load is applied to the motor. When a load is applied to the motor, it increases in speed quickly to its maximum speed and remains there until the load is removed from the motor.

Abstract: Embodiments in accordance with the present invention provide a magnetic disk drive with reduced noise during seek operation without causing any delay in control response. According to one embodiment of the present invention, a control circuit of a magnetic disk drive controls the drive power supplied to a voice coil motor during a seek operation adapted to move a magnetic head over a target track formed on a magnetic disk so as to bring the travel speed of the magnetic head close to a predetermined target speed. The control circuit determines a provisional current according to the difference between the predetermined target speed and an actual travel speed in an acceleration zone adapted to accelerate the magnetic head to the predetermined target speed. If the provisional current exceeds a limit specified in relation to an elapsed time from the start of acceleration, the control circuit sets the limit as the current of the drive power supplied to the voice coil motor to control the motor.

Abstract: A drive control device is provided with a determining section and a voltage increasing section. The determining section determines if the actual acceleration is deficient in comparison with the acceleration requested by the driver or if the generator output is deficient in comparison with the acceleration requested by the driver. The voltage increasing section increases the voltage supplied to the electric generator from a vehicle mounted electric power source when the determining section determines that the actual acceleration or the generator output is deficient. As a result, the generator output deficiency is eliminated and the required motor torque is produced, thereby enabling the vehicle to start into motion appropriately in accordance with the acceleration requested by the driver.

Abstract: A system and method for improving transient speed response of electric motors includes a comparator that determines a difference between a current reference and an adjusted current reference generated by the electric motor drive system, and an integrator the receives and integrates the difference between the current reference and the adjusted current reference over time to yield total accumulated lost current-seconds, and outputs at least a portion of the integrated difference between the current reference and the adjusted current reference as current-seconds to be added to the current reference. The present invention keeps track of the total accumulated loss-seconds due to current rate limitations, and restores the total accumulated lost current-seconds to the system when current becomes available.

Abstract: An image detecting apparatus comprises a rotating disk having pinholes that allow light to pass through, a photosensor for detecting the rotation of the disk, a CCD camera for capturing a confocal image of a specimen passed through the pinholes of the disk, a brushless DC motor for rotating the disk at a given speed, and an FPGA which produces a pulse-like brake signal having two levels for accelerating and decelerating the disk and its pulse width set variable and outputs it to the DC motor, thereby allowing the synchronization of the rotation of the disk with the image capture timing of the CCD camera.

Abstract: A method for starting-up in a desired forward sense of rotation a multiphase, brushless, sensorless, DC motor, while limiting the extent of a possible backward rotation. First, a predetermined initial phase is excited (thereby accelerating the rotor toward an equilibrium position for that initial phase), for only a fraction of the time necessary for the accelerated rotor to travel through a nearest angular position which would determine a "zero-crossing" in the waveform of any one of the back electromotive forces (BEMFs) which are induced by the rotor on the windings of the motor. After the elapsing of this brief impulse of excitation, the sign of the BEMFs induced in the windings of the motor are digitally read thus producing a first reading.

Abstract: The present invention solves the problem of discontinuous operation of an elevator door, depending upon the operating point of the door at the time of the reversal command, by a digital control technique which uses as a reference signal for the adaptation, the velocity dictation coming from a profile generator. This gives an information concerning the actual operating point. The adaptation of the controller parameters is made with respect to the signal.