Abstract: A servo controller, capable of controlling the motion of a movable body with high accuracy, without depending on the position of the movable body which is moved on a ball screw. The servo controller has a position command generating part which generates a position command value; a velocity command generating part which generates a velocity command value based on the position command value and a position detection value; a torque command generating part which generates a torque command value based on the velocity command value and a velocity detection value; and a position compensation calculating part which calculates an amount of expansion/contraction of the ball screw based on a distance from the servomotor to a nut threadably engaged with the ball screw and the torque command value, and calculates a position compensation based on the amount of expansion/contraction.

Abstract: Embodiments of the invention provide a variable frequency drive system and a method of controlling a pump driven by a motor with the pump in fluid communication with a fluid system. The drive system and method can provide one or more of the following: a sleep mode, pipe break detection, a line fill mode, an automatic start mode, dry run protection, an electromagnetic interference filter compatible with a ground fault circuit interrupter, two-wire and three-wire and three-phase motor compatibility, a simple start-up process, automatic password protection, a pump out mode, digital input/output terminals, and removable input and output power terminal blocks.

Abstract: Provided is a horizontal machine tool which achieves remarkable accuracy improvement by correcting spatial accuracy while stabilizing the swing of a main spindle. To this end, a horizontal machine tool (10) is provided with: a ram tension bar (20) which corrects the deflection of a ram (17); a lifting force correction mechanism (30) which corrects the inclination of a saddle (16) by adjusting lifting force at two positions where the saddle (16) is lifted; a column tension bar (40) which corrects the bend of a column (14); and a control device which controls the ram tension bar (20), the lifting force correction mechanism (30) and the column tension bar (40) and has a spatial accuracy correction function of correcting the spatial accuracy by numerical control.

Abstract: A motor control apparatus includes a position controller that generates a velocity command on the basis of a position difference between a position command and a position feedback signal, a switcher that switches the position feedback signal to be input to the position controller from a first position signal detected by a laser interferometer to a second position signal detected by a position sensor, and a phase compensator that compensates for a phase delay of the second position signal switched by the switcher relative to the first position signal.

Abstract: Disclosed is a method for suppressing a speed ripple occurring during an operation of an AC motor by using a torque compensator based on an activation function. The method includes the steps of calculating a speed error ?err based on a reference speed ?ref and an actual speed ?act; calculating a controller output Trm by using the speed error ?err as an input of a PI control and an operation of a compensated torque Tcom; and determining a torque variation based on the controller output Trm and a reference torque Tref and operating the torque variation in relation to an anti-windup gain Ka to use torque variation as an input of an integral (I) control. The method suppresses the speed ripple by compensating for the torque ripple through a controller which calculates the compensated torque by taking the signs of the speed error and the differential speed error into consideration.

Abstract: A stepper motor driver system includes: a digital signal controller configured to digitally synthesize synthesized analog voltage signals that will induce a desired velocity of a stepper motor when applied to a pair of stepper motor windings; and voltage amplifiers, communicatively coupled to the digital signal controller, configured to amplify the synthesized analog voltage signals to produce amplified analog voltage signals and to output the amplified analog voltage signals; where the digital signal controller is configured to synthesize the analog voltage signals by affecting at least one of a phase or an amplitude of each of the analog voltage signals as a function of the desired velocity of the stepper motor.

Abstract: An active motor damping system and method for dampening oscillations of a driveline in a vehicle includes generating a commanded torque indicative of an actual torque which would counteract the oscillations if delivered by a motor to the driveline. The commanded torque is adjusted as a function of a phase lag between the commanded torque and an actual torque which the motor would deliver in response to the commanded torque such that in response to the adjusted commanded torque the motor delivers the actual torque which counteracts the oscillations.

Abstract: A position control apparatus calculates a position detection value by adding an output of a first-order delay circuit 17 that receives a difference between a driven member position detection value Pl and a motor position detection value Pm to the motor position detection value Pm, and uses the obtained position detection value as a position feedback value. An aging corrector 30 suppresses low frequency vibrations by controlling a time constant Tp of the first-order delay circuit 17 in such a way as to increase the time constant when a vibratory state of the driven member is detected.

Abstract: A motor control device to execute speed control and position control of motor simultaneously, includes a target position information provider, a target speed information provider, a detected position information detector, a processor to add position feedback information, position feed-forward information, speed feedback information, and speed feed-forward information for output as motor control information, based on the target position information, the setting target speed information, and the detected position speed information, a control voltage generator operatively connected to the processor to generate a control voltage to drive the motor in accordance with the motor control information, and a motor driver operatively connected to the control voltage generator and the motor to control rotation of the motor based on the control voltage.

Abstract: An apparatus includes an inverter including a high-side switch coupled to a low-side switch, the inverter generating a time-varying drive current from a plurality of drive control signals, a positive rail voltage, and a negative rail voltage wherein controlling the switches to generate the time-varying drive current produces a potential transitory overshoot condition for one of the switches of the inverter; a drive control, coupled to the inverter, to generate the drive control signals and to set a level of each of the rail voltages responsive to a plurality of controller signals; and a controller monitoring one or more parameters indicative of the potential transitory voltage overshoot condition, the controller dynamically adjusting, responsive to the monitored parameters, the controller signals to reduce a risk of occurrence of the potential transitory voltage overshoot condition.

Abstract: A method for ascertaining measured values in a cyclically controlled system, the cyclic control having control time periods in which the system is controlled, and no-control time periods in which the system is not controlled, having the following operations of determining first integration time periods as a function of the cyclic control, the first integration time periods being situated within at least one of the control time periods, and/or determining second integration time periods as a function of the cyclic control, the second integration time period being situated within at least one of the no-control time periods; detecting one of the measured variables of the system dependent on the control; ascertaining summation and/or integration values by summation and/or integration of the measured variable during the first and/or second integration time periods; ascertaining the measured value for at least one of the control time periods and/or no-control time periods on the basis of time data of the first and/

Abstract: In an adder circuit, a sine wave is added to a compensation signal which is generated based on a position detection signal of a member to be driven and for compensating a position of a lens which is the member to be driven. An absolute value integrating circuit integrates absolute values of signals before and after the adder circuit adds the sine wave. The two obtained integrated values are compared by a comparator circuit, and a gain adjusting circuit adjusts a gain of an amplifier which amplifies the compensation signal so that the two integrated values are equal to each other.

Abstract: A system, in one embodiment, includes a drive having a housing, a stator disposed in the housing, a rotor disposed in the stator, and a programmable logic controller disposed inside, mounted on, or in general proximity to the housing. In another embodiment, a system includes a network, a first motor having a first integral programmable logic controller coupled to the network, and a second motor having a second integral programmable logic controller coupled to the network. In a further embodiment, a system includes a rotary machine having a rotor and a stator disposed concentric with one another, a microprocessor, memory coupled to the microprocessor, a power supply coupled to the microprocessor and the memory, and a machine sensor coupled to the microprocessor.

Abstract: A high acceleration rotary actuator motor assembly is provided comprising a plurality of phase motor elements provided in tandem on a shaft, each phase element including a rotor carrying magnets which alternate exposed poles, the rotor being connected to the shaft and surrounded by a stator formed of a plurality of interconnected segmented stator elements having a contiguous winding to form four magnetic poles, the stator being in electrical communication with a phase electric drive unit, wherein each of the poles exert a magnetic force upon the magnets carried by the rotor when the poles are electrically charged by the phase electric drive unit. The rotors and magnets of each phase motor element are offset about the shaft from one another. In addition, the phase motor elements are electrically isolated from one another.

Abstract: A method of correcting a sensor that detects a detection object and generates a detection signal includes: determining a homing-signal generation time difference between points of time when the detection signal is generated according to a direction in which the detection object enters the sensor and correcting a homing-signal generation time by using the determined homing-signal generation time difference.

Abstract: In position tandem control in which one movable member is driven by two motors, an output of the integral element of the velocity control unit in the control system for one motor is copied to the integral element of the velocity control unit in the control system for the other motor. A preload is added to a torque command output from each of the velocity control units in the motor control systems for two motors so that torques in mutually opposite directions are generated to suppress backlash between gears.

Abstract: A method for controlling positioning of an actuator having a wave gear device uses an exact linearization technique to compensate effects relative to positioning control of a load shaft caused by the non-linear spring characteristics of the wave gear device. A plant model is constructed from the actuator, and linearized using the exact linearization technique; measurements are taken of non-linear elastic deformation of the wave gear device relative to load torque; the non-linear spring model ?g(?tw) is defined using a cubic polynomial with the constant defined as zero to allow the measurement results to be recreated; and the current input into the model and motor position of the model when a load acceleration command is a command value are entered into a processor arranged as a semi-closed loop control system for controlling positioning of the load shaft, as a feed-forward current command and a feed-forward motor position command.

Abstract: A controller for an electro-mechanical actuation system (e.g., missile fin actuator) includes a Kalman estimator circuit generating an estimate of operating state including position and velocity of motor, position and velocity of a position-controlled element (PCE), and motor current. The estimate is generated based on a dynamic model explicitly including the effect of structural stiffness and damping in the coupling between the motor and PCE, for example by treating it as a mechanical oscillator having spring and damping constants. The Kalman estimator operates on a motor drive control signal and a measured position signal which may be from a Hall sensor sensing motor position. A linear quadratic regulator circuit applies a state feedback gain matrix to a state vector to generate a control effort signal. The state feedback gain matrix minimizes a quadratic cost function representing variance of the control effort signal and/or the measured position signal.

Abstract: A torque ripple suppression control device for a permanent magnet motor includes a current command conversion unit that outputs a current command value, a position detector that detects a rotational position of the permanent magnet motor, a current detection unit that detects a current at the permanent magnet motor, an induced voltage coefficient setting unit that outputs an information signal related to an induced voltage coefficient for an induced voltage at the permanent magnet motor, a torque ripple suppression operation unit that outputs a current correction command value for the permanent magnet motor, a current control operation unit that outputs a voltage command value based upon addition results obtained by adding together the current command value and the current correction command value and the current detection value, and a power converter that outputs a voltage with which the permanent magnet motor is to be driven.

Abstract: A rotating element control system includes a rotating element rotatably disposed on a main body, a first sensing unit which senses a rotational speed of the main body, a driving unit which drives the rotating element, a second sensing unit which senses a rotational speed of the rotating element, a torque compensation unit which generates a first compensation signal within a first range and a second compensation signal within a second range, and a stabilization control unit which controls the driving unit based on the first and second compensation signals and a difference between a speed of a command to drive the rotating element and the rotational speed of the rotating element.

Abstract: A technique is provided for verifying the proper selection, installation, communication and operability of components in power electronic systems, such as motor drives. A processing circuit is coupled to multiple components or subsystems that identify themselves to the processing system. An identification code is stored that is compared to a similar code built based upon the information reported by the components at the time of commissioning, operation or servicing. If the comparison indicates that all components are properly installed, and communicating and operative, operation may continue. The technique may be applied in parallel motor drives at a power layer level to allow separate and parallel verification of component and component operation in the parallel drives.

Abstract: Methods, systems and computer program products for compensating repeatable timing variations associated with a spindle motor are described. Specifically, a repetitive error correction factor may be determined using a computational model which predicts timing variations. The correction factor can then be used to cancel the effect of the actual timing variations upon the spindle motor.

Abstract: The present invention provides a position sensorless control method of a high performance permanent magnet synchronous motor during emergency operation, which can accurately detect a magnetic pole position of the synchronous motor based on a position sensorless vector control using an adaptive observer configured based on a permanent magnet synchronous motor model.

Abstract: A driving speed Vd that is a speed of a driving force input point at which a driving force from a driving element is transmitted to an elastic member is acquired. An approximate rate Ve of change of an amount of elastic deformation Pe is computed based upon a plurality of values of the amount of elastic deformation Pe acquired as a quantized value at different points in time, by smoothing out an abrupt change in the values of the amount of elastic deformation Pe caused to appear by quantization. A deformation speed V is computed based upon the driving speed Vd and the approximate Ve by: V=A·(?Vd)+B·Ve where A is a coefficient increasing with increase in frequency of fluctuations in a position of the driving force input point, and B is a coefficient increasing with decrease in the frequency of fluctuations in the position of the driving force input point.

Abstract: A control apparatus of an alternating-current motor includes an inverter which is connected to a direct-current source and outputs three-phase alternating currents to the alternating-current motor, a current detector which detects a current of the alternating-current motor, a voltage command/PWM signal generation unit which calculates an output voltage command of the inverter based on a signal from the current detector and generates a pulse width modulation signal to control a switching element arranged in the inverter based on the output voltage command, and a motor current imbalance compensation unit which generates a motor current imbalance compensation amount based on the current detected by the current detector. The pulse width modulation signal is directly or indirectly adjusted at the voltage command/PWM signal generation unit based on the motor current imbalance compensation amount in accordance with a driving state of the inverter.

Abstract: A system for maintaining thermal stability of a motion stage driven by a motor comprises a motion current generator operative to produce a motion current to drive the motion stage to move and a thermal current generator operative to produce a thermal current to dissipate heat in the motion stage for controlling a temperature of the motion stage without producing corresponding movement of the motion stage. A summation controller is operative to combine the motion current with the thermal current, and to produce a combined current output to the motor.

Abstract: A two-phase or four-phase electric machine includes a first stator part and a second stator part disposed about ninety electrical degrees apart. Stator pole parts are positioned near the first stator part and the second stator part. An injector injects a third-harmonic frequency current that is separate from and not produced by the fundamental current driving the first stator part and the second stator part. The electric angular speed of the third-harmonic rotating field comprises p · ? t , where p comprises the number of pole pairs, ? comprises a mechanical angle and t comprise time in seconds.

Abstract: A servo system is provided for controlling movement of a flexible structure having multiple masses and elements. Each element couples a respective two of the masses and functions as a spring when the flexible structure is subject to a linear or rotational input at or above a frequency at which the respective element exhibits flexure. The servo system includes multiple sensors, where each sensor is disposed relative to a respective one of the masses to sense a respective acceleration. A motor having a torque input may operatively be configured to output one of a linear or rotational force on the first mass based on a torque signal present on the torque input. A servo controller that receives each sensed acceleration from each sensor may generate a compensation feedback signal based on a sum of sensed accelerations. The torque signal may be output to the motor based on the compensation feedback signal.

Abstract: The stage device of the present invention includes a linear motor having a coil and a plurality of permanent magnets, a current driver that supplies current to the coil, and a control section that generates a command for the current driver. The control section generates the command through commutation processing in which a sinusoidal wave using an electrical angle obtained by calculation based on the relative position between the coil and the permanent magnet is multiplied by a thrust force command value for the linear motor, and further ensures that a sinusoidal wave component, which has an amplitude proportional to a thrust force command value and is 90 degrees out of phase from the sinusoidal wave, is included in the command.

Abstract: A motor control apparatus includes a sub-controller including a two-degree-of-freedom repetitive compensator and a shaping filter. The two-degree-of-freedom repetitive compensator includes a forward delay placed in a forward route of a loop and a feedback delay placed in a feedback route thereof and is configured so that a total delay time provided by the forward delay and the feedback delay is equal to the cycle of a target command or a disturbance. The shaping filter is configured so that the product of the pulse transfer function of the two-degree-of-freedom repetitive compensator and the complementary sensitivity function of a general-purpose control system has a low-pass characteristic.

Abstract: A drive unit comprising of a driving motor and of at least two flexible linking members, which twist on each other when a rotational shaft of the driving motor rotates and thus produce a pulling force on a motion element that is attached to or is a part of link of a legged robot's leg mechanism is disclosed. A control method to control the invented drive unit so that a passive, a passive-dynamic or an active walking modes and transition between the modes of a legged robot is achieved without any additional mechanical means is disclosed.

Abstract: A motor control system includes a motor unit and a controller unit electrically connected therewith. The motor unit includes a motor, a resolver detecting a rotational angle of the motor and a first memory storing first error data for detection by the resolver of the motor's rotational angle. The controller unit includes a second memory storing second error data for detection by the resolver of the motor's rotational angle and a motor controller determining an actual rotational angle of the motor according to the detected rotational angle detected by the resolver and the second error data in the second memory and controls the motor's rotation according to the determined actual rotational angle. The motor unit or the controller unit further includes an update section updating the second error data with the first error data according to motor data in the first and second memories.

Abstract: A motor controller for determining a position of a rotor of an AC motor, the motor controller comprises a control input for receiving a control signal, an output for providing a power control signal for controlling power applied to a stator of the AC motor, and an input for receiving a feedback signal representative of the current in the stator. The control input and output are coupled by a reference path, and the input is coupled to the control input by a feedback path. A carrier signal injection element injects a high frequency carrier signal in the reference path at an injection node. The motor controller is arranged to generate the power control signal in dependence on the control signal, the feedback signal, and the high frequency carrier signal. A position determining element generates a position signal representing the position of the rotor in dependence on the feedback signal which includes a carrier signal component comprising rotor position information.

Abstract: A motor speed controller detects out-of-control reverse rotation of a motor even when the pulse signal obtained from the motor and synchronized with the rotation is of only one kind. A target instruction signal is generated on the basis of a target rotational speed ?T of the motor. A compensation instruction signal is generated on the basis of an error signal Ve that corresponds to a difference between the actual rotational speed ? and ?T. A composite signal is generated by combining above two instruction signals. A state in which the control direction of the composite signal with respect to ? is the reverse of the direction of ?T, and the strength of the composite signal exceeds a designated threshold continues for a designated period, is judged as a state of out-of-control reverse rotation, and restoration to the normal state is performed.

Abstract: A motor controller capable of detecting an oscillation of a feedback loop and performing gain adjustment while updating a gain value of a control unit is provided. The motor controller includes an electric motor, an operation-amount detector, a control unit, a machine, a disturbance signal generator which generates a sweep sine wave, a compensation-driving-force detector, a vibration calculator, an oscillation detector, a vibration storage, a simulated open-loop gain calculator, a gain changer, and an automatic gain changer, and detects an oscillation by processing a response signal in time series on the basis of a first threshold regarding to a magnitude of vibration and a second threshold regarding a frequency.

Abstract: The present invention relates to a frequency converter comprising electric power supply devices for supplying electric power to an electric motor (26) to be connected to the frequency converter, a controller configured to control the electric power supply. In order to control the electric power supply, the frequency converter comprises a joystick (22) for conveying control signals to the controller, the joystick (22) comprising an acceleration sensor for registering movements of the joystick (22) and for generating control signals representing the movements, and a switch (24) for triggering a control cycle during which the controller receives the control signals generated by the joystick (22) for utilizing the control signals in controlling of the electric power supply.

Abstract: Methods and systems are provided for producing a commanded torque in an electric motor in a vehicle. A method comprises obtaining a torque command, obtaining a speed of the electric motor, and operating the inverter based at least in part on a voltage command that corresponds to minimal current through the electric motor for producing the commanded torque at the instantaneous speed of the electric motor.

Abstract: A method of detecting an angular position of a rotor of a motor includes detecting switching ripple peaks and armature current disturbance peaks using a peak detector configured to generate a square wave having edges coinciding with detected peaks. The method further includes filtering the square wave in a time domain by generating an integration ramp, toward a set value, of an estimated ripple frequency for an interval of time based on the estimated ripple frequency. An enablement range is established to reset the integration ramp by setting a threshold below and above the set value and a time window centered on an end time of each period of the estimated ripple frequency. The method further includes resetting the integration ramp, and updating the estimated ripple frequency based upon a period determined by a time of the resetting, if an edge of the square wave is within the time window.

Abstract: The controller includes a position commander and an error corrector. The position commander outputs a position command value for moving a moving mechanism. The error corrector includes a feedforward controller and a compensator calculator. The feedforward controller performs a feedforward control of the moving mechanism based on the position command value outputted from the position commander and includes a compensator. The compensator calculator calculates a value to be set as the compensator of the feedforward controller based on the position command value outputted from the position commander.

Abstract: A control system for a lifting device in which a load moves up or down or maintains its position by a rope that is wound up or down by the rotation of a servo motor. It includes a device for measuring a force, a first controller, a second controller and a switching device. A total force that is applied at the lower part of the rope caused by a force for controlling, the mass of the load, and the acceleration of the load is measured. The first controller, based on the measured force computes the direction and the speed of the servo motor, and outputs a signal to it. The second controller determines a stable condition using Popov's stability criterion. The switching device replaces the first controller with the second controller when the value that is measured by the measuring device becomes less than a threshold.

Abstract: According to an embodiment, a numerically controlled (NC) processing system includes materials processing installation having a multi-axis kinematic linkage operable to position a tip portion of the linkage along a predetermined process path. The system also includes a processor having a compensation system operable to detect a singular point in the process path and to improve the accuracy tip portion positioning near the singular point.

Abstract: A servo control apparatus capable of suppressing adverse effects of disturbance, load variation and the like, and realizing robust and high-performance speed control. The apparatus includes both of the following observers: a disturbance observer for adding a disturbance compensation torque Tf, calculated from a torque command T* and an electric motor rotational speed ?m, to a torque command basic signal T0*, calculated on the basis of a deviation between a speed command ?* and a feedback speed ?f by a PI control section, thus outputting the torque command T*; and a phase advance compensation observer for generating, from the torque command basic signal T0* and the electric motor rotational speed ?m, an output of a nominal plant serving as an element in which no delay occurs, thus outputting the output as the feedback speed ?f.

Abstract: A method of detecting a useful signal from a measurement signal that is overlaid by at least one interference signal for use in a control or regulating device, where the interference signal occurs with at least one known interference signal frequency. The method including the steps of detecting the measurement signal, performing a Fourier transformation on the measurement signal with reference to the interference signal frequency to detect the interference signal amplitude and phase, detecting the interference signal on the basis of the interference signal amplitude and phase, and removing the interference signal from the measurement signal to detect the useful signal. The Fourier transformation is performed only with reference to the known interference signal frequency to simplify the computation making it possible to detect the useful signal in real time.

Abstract: In a position control apparatus that drives a feed-axis with a servomotor of a machine tool, the machine tool may be quickly accelerated or decelerated in a state where a machine structural member that supports and fixes a structural member including a driving system has a lower rigidity, or in a state where an element having a lower rigidity is present beyond a load position where the detection by a linear scale is performed. In such cases, a generated deflection may induce a displacement in a mechanical system. A relative locus error may be generated between a workpiece to be processed and a front end portion of the tool. Further, a mechanism rigidity generally changes according to a machine posture. The generated deflection amount changes in magnitude. The present embodiment estimates and compensates a displacement amount of the front end portion of the tool that may be caused by the deflection of the mechanical system.

Abstract: A numerical controller for controlling a multi-axis machine calculates an axis-dependent translation error amount and an axis-dependent rotation error amount based on a command axis position. Translation and rotation compensation amounts are calculated based on the axis dependent translation and rotation error amounts, respectively. The translation and rotation compensation amounts are added to command linear and rotary axis positions, respectively. Three linear axes and three rotary axes are driven to the added positions, individually. Thus, there is provided a numerical controller that enables even machining with a side face of a tool or boring to be in commanded tool position and posture (orientation) in the multi-axis machine.

Abstract: A controller for an electro-mechanical actuation system such as a missile fin actuator includes a Kalman estimator circuit which generates an estimate of operating state including position and velocity of motor, position and velocity of a position-controlled element (PCE), and motor current. The estimate is generated based on a dynamic model explicitly including the effect of structural stiffness and damping in the coupling between the motor and the PCE, for example by treating it as a mechanical oscillator having spring and damping constants. The Kalman estimator operates on a motor drive control signal and a measured position signal which may be from a Hall sensor sensing motor position. A linear quadratic regulator circuit generates a control effort signal by applying a state feedback gain matrix to a state vector. The state feedback gain matrix minimizes a quadratic cost function representing variance of the control effort signal and/or the measured position signal.

Abstract: In an adder circuit, a sine wave is added to a compensation signal which is generated based on a position detection signal of a member to be driven and for compensating a position of a lens which is the member to be driven. An absolute value integrating circuit integrates absolute values of signals before and after the adder circuit adds the sine wave. The two obtained integrated values are compared by a comparator circuit, and a gain adjusting circuit adjusts a gain of an amplifier which amplifies the compensation signal so that the two integrated values are equal to each other.

Abstract: A servomotor controller capable of properly generating reference positions, by which learning control of angle based method may be applied to the periodically reciprocating motion of an object. The learning controller obtains a first positional deviation of a driven object at every predetermined sampling period of time, and the first positional deviation is converted, by a first converting part, to a second positional deviation associated with each reference position in one periodic reciprocating motion of the driven object. After a first correction amount of an immediately previous reciprocating motion of the driven object, stored in a memory, is added to the second positional deviation, the second positional deviation is stored in the memory as a renewed first correction amount. The first correction amount is converted to a second correction amount associated with the sampling period, by a second converting part.

Abstract: Improved precision is realized in positioning control. Provided is a servo control device that is applied to a numerical control equipment provided with a screw-feeding section that converts rotational movement of a motor to linear movement, a driven section that is linearly moved by the screw-feeding section, and a support member by which the screw-feeding section and the driven section are supported and that controls the motor so as to match a position of the driven section to a positioning instruction, including a support-member-reaction-force compensating section 311 that compensates for vibrations of the driven section due to a vibrational reaction force of the support member, wherein a transfer function provided in the support-member-reaction-force compensating section 311 includes a stiffness term for the driven section.

Abstract: Methods and apparatus are provided for deriving precision position and rate information for motors using relatively low precision analog sensors, and for implementing compensation techniques that overcome inherent sensor errors and rotor magnet flux tolerances.