Abstract: The actuation system including a control system, an actuator comprising a drive part and a step motor comprising a rotor and a stator with at least one electric phase, an actuated system comprising a controlled element coupled to the drive part, and an elastic part capable of generating an elastic return force on the rotor of the motor or on the drive part. The control system comprises means for measuring an induced electric parameter on the phase of the stator after switching off the current of said at least one phase of the stator to detect a return of the rotor resulting from elastic return force when a mechanical clearance is overtaken.

Abstract: A meter system includes: an indicator including a pointer, a step motor, a stopper mechanism and a driving controller; and a flasher function unit including a flasher switch, a flasher and a flasher controller. The driving controller has: a stopper position detection operation executing element for executing a pointer moving away operation when a stopper position detection operation executing condition is satisfied and for executing a voltage detection type zero point stopper position detection operation when the executing condition is satisfied, and the flasher switch does not turn on and off, and a zero point return enforcement type zero point stopper position detection operation when the executing condition is satisfied, and the flasher switch turns on and off; a zero point setting element; and an applying element for applying the driving signal having the zero point.

Abstract: A method of driving a stepper motor in a feed-forward voltage mode may include for a desired speed for the stepper motor setting an amplitude of a sinusoidal phase voltage of the stepper motor to be equal to a sum of an expected back-electromotive force (BEMF) amplitude estimated as a function of the desired speed, and a product of a desired phase current amplitude and an estimated absolute value of an impedance of the stepper motor.

Abstract: A drive system is disclosed for operating an electric device. The drive system includes an electric motor having a permanent magnet rotor connectable to the electric device for controlling the operation of it by a limited-angle rotation, the electric motor further including a stator winding. The drive system includes a drive circuit connected to the stator winding. The permanent magnet rotor can be arranged to be aligned to a magnetic field created by the stator winding when supplied with current from the drive circuit, so that a maximum torque can be applied to the rotor and thereby to the movable part within an interval of ±25 degrees around a middle position between two end positions of the limited-angle rotation of the rotor.

Abstract: A control system for a massage device. The massage device has a base, a carriage movably engaged with the base, a plurality of kneading heads mounted on the carriage, and a motor operative to drive the plurality of kneading heads to produce a kneading effect on a body of a user and to drive the carriage up and down relative to the base such that various areas of the body can be massaged.

Abstract: An apparatus including a DC motor includes a driven member configured to be driven by the DC motor, and a drive control unit configured to define a plurality of predetermined phases of the DC motor as target stop phases and to cause the DC motor to make at least one rotation to perform preliminary driving that rotates the DC motor to each target stop phase by driving and stopping the DC motor, configured to acquire a difference value between the target stop phase and an actual stop phase for each target stop phase, and configured to drive the DC motor so that the driven member is repeatedly moved and stopped in the operation of the driven member and to perform control so that, based on the difference value acquired by the acquisition unit, electric power is supplied to the DC motor in a phase corresponding to a stop position of the driven member.

Abstract: A head up display device for a vehicle includes a display; an optical system having a reflecting mirror; a stepping motor; and a control system having a determining device, a micro-step control device, and a forcible control device. The determining device determines whether an adjustment command for micro-step control is given. The micro-step control device performs the micro-step control as long as the determining device determines that the command for the micro-step control is given. The forcible control device forcibly controls a drive signal such that an electrical angle changes to a stabilizing point. When determination made by the determining device switches from determination that the command is given to determination that the command is not given, the forcible control device forcibly controls the drive signal, provided that the electrical angle as of the time of the determination that the command is not given is shifted from the stabilizing point.

Abstract: The motor drive apparatus includes a driven member, a stepping motor to drive the driven member, a driver to produce a drive signal for driving the stepping motor and whose signal value periodically changes, a memory to store data for setting a reference signal value as the signal value and a target movement amount of the driven member for each one-step drive of the stepping motor to be driven according to the drive signal having the reference signal value, and a detector to detect an actual movement amount of the driven member for each one-step drive of the stepping motor actually driven according to the drive signal having the reference signal value. The driver changes the signal value of the drive signal from the reference signal value to another signal value so as to reduce difference between the target movement amount and the actual movement amount.

Abstract: In a drive of a stepping motor, an electromotive force is generated on the coil of a motor with a sinusoidal wave having the same period as an energization period by smoothly rotating a rotor with microstep driving, and an induced power is stably detected by detecting the electromotive force at the zero cross of driving current. The detection around the current zero cross makes it possible to shorten a detection section, form a driving waveform with few distortions, and perform driving with a driving waveform as in an ordinary micro step. Thus a circuit is provided which is aimed at reducing noise, vibrations, and loss of synchronization, and increasing current consumption efficiency in the determination of stop.

Abstract: An apparatus for controlling a stepper motor comprises a driver circuit and a brake circuit each having a motor controller device. The driver circuit, brake circuit and motor are connected in parallel. The driver circuit receives an enabling signal and outputs driver current to the motor accordingly. The brake circuit includes a logic circuit which receives the enabling signal, a brake input signal, and a power supply status signal, and outputs a brake logic signal. The brake circuit motor controller device is coupled to the logic circuit. This motor controller device receives an output of the brake logic circuit and outputs braking current to the motor in accordance therewith. The braking circuit is effective to prevent movement of the motor shaft in accordance with output of the braking current. The motor controller devices are substantially identical. The apparatus is effective to control the motor while avoiding generation of RF noise.

Abstract: An apparatus for reducing undesired motions during initialization of a stepper motor having a rotor and windings, the apparatus comprising a rotary encoder for sensing direction of rotor rotation; a microcontroller responsive to signals from the rotary encoder for generating bidirectional motor control waveforms having variable digital amplitude values; at least one motor driver for receiving the motor control waveforms and translating the waveforms to drive the motor windings; and wherein the translated waveforms urge the rotor in a first direction and then a second direction to locate a desired rotor position.

Abstract: An integrated circuit has drive circuitry to drive the windings of an electrical motor, means to make a measurement from the drive circuitry during rotation of the motor, suitable for use as motor control feedback, and has an output contact through which the motor control feedback measurement is available as an analog output signal. It can be used with an external motor control circuit coupled to receive the analog output signal to generate motor control signals, to control the drive circuitry. The analog feedback output gives more flexibility to the design of a motor control loop in terms of bit resolution, bandwidth and choice of discrete time or continuous time control.

Abstract: The control device comprises a position command creation part creating a target rotation angle value of a stepping motor, a position controller calculating the rotation speed of the stepping motor based on the deviation between the target rotation angle value and detected value, a boost command processing part calculating the boosted voltage according to the calculated rotation speed, a booster circuit boosting the motor power supply voltage, and a PWM inverter creating pulse signals supplied to the stepping motor.

Abstract: A control unit is provided which drives a stepping motor in a first mode in which a driving pulse is selected between one kind of main driving pulse and a correction driving pulse with energy greater than the one kind of main driving pulse in accordance with a rotation state of the stepping motor and the stepping motor is driven or a second mode in which the driving pulse is selected among plural kinds of main driving pulses and a correction driving pulse with energy greater than the plural kinds of main driving pulses in accordance with the rotation state of the stepping motor and the stepping motor is driven. The control unit switches a mode between the first and second modes depending on whether the voltage of a secondary cell serving as a power supply exceeds a switch voltage and drives the stepping motor.

Abstract: A method is described for controlling the operation of a metering valve driven by a stepper motor, a position sensor normally providing position information to allow control over the metering valve in a closed loop manner. The method comprises the steps of: performing a calibration operation to derive a relationship between stepper motor position and metering valve position; controlling the operation of the metering valve in a closed loop manner; and controlling the operation of the metering valve in an open loop manner in the event that the position sensor output is thought to be unreliable; wherein, when operating in the open loop manner, the metering valve is moved to a desired angular position by using the relationship derived in the calibration operation to determine the stepper motor position associated with the desired metering valve position and moving the stepper motor to the determined stepper motor position.

Abstract: The present invention aims to prevent a main drive pulse from being moved to a rank having a potential to cause a non-rotating state. A detection segment for detecting a rotating state of a stepping motor is divided into a first segment immediately after the drive with a main drive pulse, a second segment, and a third segment and, when the stepping motor is rotated by the main drive pulse, the main drive pulse is not changed when a detection signal exceeding a reference threshold voltage is detected at least in the first and second segments. When it is detected only in the first and third segments, or detected only in the third segment, the rank is moved upward and, when it is not detected in any segment, or detected only in the first segment, the rank is moved upward after the drive with a corrective drive pulse. When it is detected only in the second segment or detected only in the second and third segments, the rank is moved downward.

Abstract: A control device for the position control of a hydraulic cylinder unit has a controller which receives a set and an actual piston position and determines a preliminary manipulated variable based on the difference of the set and actual positions. A linearization unit multiplies the variable with a linearization factor and outputs it to the valve control unit so that the piston is adjusted at an adjustment speed. The linearization unit determines the factor dynamically as a function of the actual piston position and of working pressures that prevail at both piston sides. The linearization factor is determined such that a ratio of the adjustment speed to the difference of the set and actual positions is independent of the actual position and the working pressures. In the specific case where the controller is configured as a P controller, the order of the controller and the linearization unit can be reversed.

Abstract: A drive apparatus includes a magnet rotor having a plurality of magnetic poles that are magnetized, a stator having a magnetic pole portion that opposes each pole of the magnet rotor, a coil configured to excite the magnetic pole portion, a position detector configured to detect a position of the magnet rotor, a first driver configured to switch an electrification state of the coil in accordance with a preset time interval, a second driver configured to switch an electrification state of the coil in accordance with an output of the position detector, and a controller configured to select the first driver when the output of the position detector is less than a first threshold, and to select the second driver when the output of the position detector is equal to or larger than the first threshold.

Abstract: Embodiments of the invention are directed to systems and methods for accurate positioning of a unit movable by a drive system. The method may include adjusting tension of a resilient element of the drive system to reduce hysteresis motion errors of the resilient element below a predetermined threshold by performing measurements of the hysteresis motion errors of the resilient element for two or more tension values and selecting a tension value for which the hysteresis motion error is below the threshold.

Abstract: A gaming machine having spinning reels and methods for operating the gaming machine use a computer and/or software instructions to align a home position of each spinning reel or a home position of a reel strip mounted on each spinning reel with a target position on the gaming machine. An optical detector unit using an optical strip on the spinning reel may be used to align a home position with a pay line on the gaming machine.

Abstract: An angle detecting apparatus includes a rotor fixed to a rotating shaft, a pair of magnetic sensors arranged close to the outer periphery of the rotor so as to have a difference in angle (?/2) with respect to the center of rotation of the rotor, a differential operational circuit performing differential operation on detection signals output by the magnetic sensors to output a differential signal, and the angle calculating circuit calculating the angle of rotation of the rotating shaft based on the differential signal. The planar shape of the rotor is such that the sum of the distances between the center of rotation and the respective two points where two straight lines crossing at the center of rotation at a crossing angle of (?/2) cross the outer periphery of the rotor is constant, and the planar shape is symmetric with respect to a straight line passing through the center of rotation.

Abstract: The invention relates to a method and device for transferring signal data from a sender to one or more receivers. The invention includes receiving a quantity as a function of time, arranging the quantity into a first polynomial to obtain values for polynomial coefficients of a first continuous signal, and transferring the values of the polynomial coefficients of the first continuous signal via a first data transfer link to one or more receivers.

Abstract: An apparatus, system, and method are disclosed for stepper motor 102 stall detection. A conversion module 106 receives 1206 a back electromotive force (“EMF”) waveform 1002 produced in a non-driven coil of the stepper motor 102 by a magnetic field of a rotor of the stepper motor 102 during a full step operation 308, and samples 1208 the waveform 1002 at intervals starting at a predetermined time for a predetermined period of time within the full step operation 308 to yield a plurality of sampled data points. A rectification module 202 rectifies 1210 the waveform 1002 about a predetermined quiescent level 306. A comparison module 204 accumulates 1216 the rectified sampled data points into a statistically representative sampled value, compares the representative sampled value to a predetermined threshold level, and indicates 1224 a stall of the rotor if the representative sampled value is less than the predetermined threshold level.

Abstract: An optical apparatus ensuring smooth driving control of an optical member is disclosed. The optical apparatus includes an optical member, a stepping motor configured to drive the optical member, a driving commander configured to generate driving pulses supplied to the stepping motor, a pulse count generator configured to count the driving pulses output from the driving commander, a position detector configured to detect a position of the optical member, and a pulse count presetter configured to replace, based on an output of the pulse count presetter and an output of the position detector, a pulse count output from the pulse count presetter with a pulse count corresponding to the output of the position detector.

Abstract: A stepping motor drive circuit includes a control-purpose controller including a control-purpose position detecting unit; a rotation command information inputting unit arranged to receive command information on the rotating position of the stepping motor; a control-purpose deviation calculating unit arranged to calculate a positional deviation between the rotating position of the stepping motor detected by the control-purpose position detecting unit and the rotating position included in the command information; and an amplitude value setting unit. The amplitude value setting unit switches operations of stator coils of the stepping motor pursuant to the command information, rotate the stepping motor to the rotating position included in the command information, and increase or decrease an amplitude value of a drive current fed to the stator coils during stoppage of the stepping motor depending on the positional deviation calculated by the control-purpose deviation calculating unit.

Abstract: A temperature monitoring system consists of a multielement thermopile, an analog-to-digital converter (ADC), first and second microcontrollers (MCUs), a first stepping motor, a second stepping motor, a plurality of microswitches and a monitoring apparatus. The multielement thermopile is connected to the ADC linked with the first MCU, and the first MCU is further connected to the first stepping motor with microswitches for vertical motion control, and the second stepping motor with microswitches for horizontal motion control. At the same time the first MCU can be connected to the second MCU and the second MCU is linked with the monitoring apparatus. A hot spot occurring in electrical heating equipment or a smoldering source hidden in upholstery can be identified and proper measures can be performed, in case of extremely high temperature, so as further to prevent a fire.

Abstract: A stepping motor includes two coils and has supply currents to the two coils with different phases so that a rotor is rotated by the two coils. During a period where one coil is in a high impedance state, an induced voltage generated at that coil is detected. An output control circuit controls the magnitude of motor drive current supplied to the two coils in accordance with the detected induced voltage state. Then, prior to entering the high impedance state from the drive state, a short-circuit period is provided for short circuiting both terminals of the coil.

Abstract: A control method of a current limit of a DC motor includes generating a reference voltage according to a preset current limit value of a DC motor; comparing the reference voltage with the voltage drop of a power control switch which drives the DC motor to generate a compare result; and controlling the power delivered to the DC motor according to the compare result in order to limit the current of the DC motor.

Abstract: In a method of detecting synchronization loss in a stepping motor, a means for applying either control current or control voltage to a coil of each phase to thereby drive a stepping motor and a means for individually measuring a back EMF voltage induced at the coil of each phase are employed, wherein application of either the control current or the control voltage at the coil of each phase is halted by turns phase by phase for such a short time period as not to affect rotation of a rotor of the stepping motor at a predetermined timing within one step period of the rotor, the back EMF voltage at the coil is measured during the short time period, and the stepping motor is judged to lose synchronization when the measurement result of the back EMF voltage at the coil of at least one phase satisfies a detection criterion.

Abstract: A valve control apparatus including a stepping motor coupled to a valve and a motor control unit for controlling the stepping motor is provided. The motor control unit includes a motor control section for applying drive pulses to the pulse motor, a counting section for counting the number of drive pulses applied to the pulse motor, a voltage-drop detecting section for detecting a voltage drop of a drive power supply for the motor control section, and a writing section for writing a count from the counting section in a nonvolatile memory if the voltage-drop detecting section detects the voltage drop.

Abstract: A drive apparatus includes a magnet rotor, a stator having a coil, a position detector configured to detect a position of the magnet rotor, a lead angle circuit configured to output a signal having a lead angle relative to an output of the position detector, a first driver configured to switch an electrification state of the coil in accordance with a preset time interval, a second driver configured to switch an electrification state of the coil in accordance with an output of the lead angle circuit, and a controller configured to adjust a lead angle amount of the signal output from the lead angle circuit within a range that does not cause step out in the driving by the first driver, prior to changing the driving by the second driver to the driving by the first driver.

Abstract: A motor-driving device comprising: a switching element to control a current passed through a first coil of a stepping motor including the first and a second coils electromagnetically coupled; a rectifier element to be energized in a ground-side-to-second-coil direction; a coil-current-detection unit to detect a current passed through the first coil; a regeneration-current-detection unit to detect a current passed through the rectifier element; a control unit to turn off the switching element when the current passed through the first coil reaches a predetermined-set current based on a detection result of the coil-current-detection unit; and a negative-current-detection unit to detect whether a negative current greater in absolute value than a predetermined-set value is passed through the rectifier element based on a detection result of the regeneration-current-detection unit, the control unit keeping the switching element off when the negative current is not passed, based on a detection result of the negative-

Abstract: A circuit arrangement for automatic, load-dependent control of at least one winding current of a respective motor winding of a self-timed bipolar stepper motor, includes a first power driver circuit for a first motor winding and a second power driver circuit for a second motor winding. The circuit arrangement includes a first XOR gate and a second XOR gate, and a first resistor connected so as to couple the first XOR gate to an anode of a first diode. A cathode of the first diode is coupled to the comparator input of the first power driver circuit via a second resistor. A third resistor is connected so as to couple the second XOR gate to an anode of a second diode. A cathode of the second diode is coupled to the current-controlling comparator input of the second power driver circuit via a fourth resistor.

Abstract: A motor driver that supplies a drive current to a stepping motor includes a decay rate controller configured to mix a first decay rate and a second decay rate smaller than the first decay rate with each other, and set a plurality of mix decay rates, a control logic circuit configured to create magnetization patterns for attenuating the drive current at the mix decay rates, and a drive current output circuit configured to output the drive current to the stepping motor in accordance with the magnetization patterns.

Abstract: A driving method of a high speed rotation stepping motor exhibiting good starting performance, its driving circuit, and a vibration motor and a fan motor employing them. The motor driven electronic apparatus comprises a two pole flat stator, a rotor consisting of a two pole permanent magnet coupling magnetically with the two pole flat stator through a gap, stopping with detent torque and secured to the rotor shaft, and a drive coil. The motor driven electronic apparatus is characterized in that at least any one of the reference voltage of an amplifier constituting a rotor position detector and the reference voltage of a comparator constituting the rotor position detector are used more than one.

Abstract: An indicating instrument for a vehicle includes a step motor including a field winding, a pointer, a stopper device for stopping the pointer, which is rotating in a zero-reset direction, at a stopper position, a detecting device for detecting induced voltage of the field winding at each of detecting points, a control device for performing zero-reset control, whereby a drive signal is controlled to rotate the pointer in the zero-reset direction. In a state of abnormal detection in which the induced voltage larger than a predetermined set value is detected at a zero point; and the induced voltage equal to or smaller than the set value is detected at a next detecting point to the zero point, the control device assumes synchronization loss of the step motor and continues the zero-reset control until an assumptive electrical angle corresponding to a rotational position of the pointer reaches the zero point.

Abstract: An indicating instrument includes a step motor having a field winding, a pointer, a reduction gear mechanism having gears, a stopper device for stopping the pointer at a stopper position, a detecting device for detecting induced voltage of the winding at each of detecting points that include a zero point corresponding to the stopper position, a control device for controlling a drive signal, and an updating device for updating the zero point based on the induced voltage during zero-reset control performed by the control device. The control device performs return control, whereby the pointer rotates to a return point in an indication value increasing direction and then returns to a waiting point in a zero-reset direction to stand by at the waiting point, prior to zero-reset control, whereby the pointer rotates from the waiting point in the zero-reset direction.

Abstract: A device-positioning pedestal capable of positioning devices of different sizes. The device-positioning pedestal comprises a plurality of guide members corresponding to the sides of the device and coming in contact with the sides of the device to position the device, at least one guide member includes a slide mechanism that supports the guide member so as to slide relative to the device-positioning pedestal member and a fixing mechanism that fixes the guide members at desired positions. The guide members are set to be adapted to the size of the device by the guide member-adjusting means separate from the device-positioning pedestal. The guide member-adjusting means adjust the position of the guide members based on the size of the device measured by device size-measuring means separate from the guide member-adjusting means or based on the data of data-recording means attached to the device-positioning pedestal.

Abstract: A method and apparatus for determining speed of a stepper motor. In one embodiment of the method, a first terminal of a first coil of the stepper motor is coupled to an input of a multibit digital-to-analog (A/D) convertor. The stepper motor's a rotor is rotated about an axis while the first terminal is coupled to the multibit A/D convertor. An analog signal is induced at the first terminal generating while the rotor is rotating about the axis. The multibit A/D convertor receives the analog signal induced at the first terminal. The multibit A/D convertor generates a plurality of multibit digital signals in response to receiving the analog signal. The multibit digital signals can be processed to determine the rotational speed at which the rotor was rotating when the A/D convertor generated the plurality of multibit digital signals.

Abstract: A monitor opening mechanism includes a first rotating shaft rotatably connected to a host and having a first toothed portion. A stepper motor is disposed in the host and includes a second rotating shaft having a second toothed portion engaging the first toothed portion. A fine-tuning control circuit board is electrically connected to the stepper motor. A first fine-tuning key is electrically connected to the fine-tuning control circuit board. When the first fine-tuning key is operated, the fine-tuning control circuit board drives the second rotating shaft to rotate, forcing the monitor to rotate with respect to the host in a first direction. A second fine-tuning key is electrically connected to the fine-tuning control circuit board. When the second fine-tuning key is operated, the fine-tuning control circuit board drives the second rotating shaft to rotate, forcing the monitor to rotate with respect to the host in a second direction.

Abstract: A linear motion control device for use in a linear control system is presented. The linear motion control device includes a coil driver to drive a coil that, when driven, effects a linear movement by a motion device having a magnet. The linear motion control device also includes a magnetic field sensor to detect a magnetic field associated with the linear movement and an interface to connect an output of the magnetic field sensor and an input of the coil driver to an external controller. The interface includes a feedback loop to relate the magnetic field sensor output signal to the coil driver input.

Abstract: A stepper motor control device includes a control device that controls an operation of a stepper motor. The control device implements a target rotational angle change computation process that calculates a target rotational angle change of the stepper motor and a divisional target rotational angle computation process that equally divides the target rotational angle change within a range not exceeding a rotational limit for loss of synchronism of the stepper motor. The divisional target rotational angle computation process divides the target rotational angle change within the range to calculate a “quotient” and a “remainder” thereof. The drive control device of the stepper motor sets the “quotient” to “quotient+1” in the case the “remainder” portion is not—and obtains a first divisional target rotational angle and a second divisional target rotational angle differing from the first divisional target rotational angle to drive the stepper motor.

Abstract: In a drive of a stepping motor, an electromotive force is generated on the coil of a motor with a sinusoidal wave having the same period as an energization period by smoothly rotating a rotor with microstep driving, and an induced power is stably detected by detecting the electromotive force at the zero cross of driving current. The detection around the current zero cross makes it possible to shorten a detection section, form a driving waveform with few distortions, and perform driving with a driving waveform as in an ordinary micro step. Thus a circuit is provided which is aimed at reducing noise, vibrations, and loss of synchronization, and increasing current consumption efficiency in the determination of stop.

Abstract: An image forming apparatus including a stepper motor, a component attached to the stepper motor, and a controller to control the stepper motor. The controller controls the stepper motor to be accelerated or decelerated, at driving frequencies that do not match a resonant frequency, in order to avoid a resonance between the stepper motor and the component, by selecting a speed control table that has the driving frequencies, which avoid the resonance. Thus, the image forming apparatus can avoid the resonance between the stepper motor and the component, minimize vibration and noise, and prevent malfunctions of the component. The image forming apparatus further comprises a first storage unit to store a resonant frequency of the component and, a second storage unit to store speed control tables having different driving frequencies, which are set according to speed control periods.

Abstract: A drive control device and a drive control method for a stepping motor are provided to reduce the number of parts and generation of vibration and noise by a stepping motor. The drive control device controls a drive frequency of the stepping motor according to a measurement value inputted. The drive control device includes storage means for storing the resonance frequency of the stepping motor based on its resonance characteristic as an output-inhibited drive frequency and control means for calculating an instruction angle for operating a needle according to the measurement value, acquiring a first drive frequency of the stepping motor, judging whether the first drive frequency is the output-inhibited drive frequency, and deciding the drive frequency by replacing the first drive frequency with the second drive frequency which is lower than the output-inhibited drive frequency if the first drive frequency is the output-inhibited drive frequency.

Abstract: A method and apparatus for driving a stepper motor and using the stepper motor as a rotary sensor when the stepper motor is not being driven.

Abstract: A system for calculating control pulse duration for optimal stepper motor performance. Duration of control pulses to a stepper motor is increased until stepper motor function begins. The duration of control pulses continues to be increased. It is determined whether stepper motor failure is detected. In response to detecting a failure, the duration of control pulses at the time of the failure is recorded. The duration of control pulses is decreased until stepper motor function is restored. The duration of control pulses continues to be decreased. It is determined whether a second failure is detected. In response to detecting a second failure, the duration of control pulses at the time of the second failure is recorded. A control pulse duration is calculated that optimizes performance of the stepper motor using recorded control pulse duration data. The calculated control pulse duration is applied to the stepper motor.

Abstract: A head up display device for a vehicle includes a display; an optical system having a reflecting mirror; a stepping motor; and a control system having a determining device, a micro-step control device, and a forcible control device. The determining device determines whether an adjustment command for micro-step control is given. The micro-step control device performs the micro-step control as long as the determining device determines that the command for the micro-step control is given. The forcible control device forcibly controls a drive signal such that an electrical angle changes to a stabilizing point. When determination made by the determining device switches from determination that the command is given to determination that the command is not given, the forcible control device forcibly controls the drive signal, provided that the electrical angle as of the time of the determination that the command is not given is shifted from the stabilizing point.

Abstract: A stepper motor device uses compensating non-sinusoidal driving values to compensate for operational non-sinusoidal drive characteristics of a motor of the device due to at least design and manufacturing imperfections in the motor. The compensating non-sinusoidal driving values may be derived using back electromagnetic force produced from the motor or using measured rotational positions of the motor when the motor is driven using known driving values.

Abstract: In a back electromotive force phase detecting device, a timing generating unit generates a timing signal indicating a start timing, an intermediate timing and an end timing of a 180-degree electrical angle period in a detection target phase, from an excitation pulse signal. A difference calculating unit receives the timing signal, and calculates a difference between a total PWM control period of the detection target phase during a first-half 90-degree period, and a total PWM control period of the detection target phase during a second-half 90-degree period. In an excitation control device, a control unit changes the capability of driving a motor based on an output of the back electromotive force phase detecting device.