Abstract: A shift range control device includes an encoder count unit, an energization control unit, a learning unit, an energization phase count unit, and an abnormality determination unit. The encoder count unit calculates an encoder count value based on an encoder signal. The energization control unit controls energization to the motor. The learning unit learns a wall position that is the encoder count value when an engaging member abuts on the wall portion. The energization phase count unit calculates an energization phase count value that is counted according to switching of the energization phase. The abnormality determination unit determines an abnormality of the encoder based on the energization phase count value and the encoder count value before and after learning the wall position.

Abstract: An encoder includes a position information generating unit that generates position information made of a predetermined amount of data and including absolute position data of an object to be detected; a configuration information generating unit that generates configuration information representing a ratio of the absolute position data in the amount of data during serial communication; and a transmission unit that transmits, to the control device, the position information and the configuration information as a series of serial data or as separate serial data. The control device includes a reception unit that receives the position information and the configuration information transmitted from the encoder; a storage unit that stores the received configuration information; and a control unit that processes the received position information on the basis of the stored configuration information.

Abstract: A system and method for replacing a sixteen-pin ECM with a non-sixteen-pin, field adjustable ECM in an HVAC or other system, and adjusting the performance of the replacement motor at the point of installation. A converter module receives programming information from an existing control board via an existing sixteen-pin harness, and converts the information to six signals. The module includes potentiometers for tuning speed/torque for first and second settings, adjusting a horsepower output of the replacement ECM, and adjusting a ramp time to increase or decrease a rate at which the speed/torque changes. The module includes switches for selecting between clockwise and counterclockwise directions for the replacement ECM, selecting between PWM and non-PWM control, and selecting between torque and speed modes. A non-sixteen-pin motor controller receives the information from the converter module via a four-wire harness, translates the information, and outputs a control signal to the replacement ECM.

Abstract: A position sensor employing silicon photodiodes formed from trapezoidal chips mounted on a printed circuit board detects angular positions of a rotor shaft within a galvanometer-based optical scanner.

Abstract: A machine tool includes an operation evaluation section that evaluates an operation thereof and a machine learning device that performs the machine learning of a movement amount of an axis thereof. The machine learning device calculates a reward based on state data including the output of the operation evaluation section, performs the machine learning of the determination of the movement amount of the axis, and determines the movement amount of the axis based on a machine learning result and outputs the determined movement amount. The machine learning device performs the machine learning of the determination of the movement amount of the axis based on the determined movement amount of the axis, the acquired state data, and the calculated reward.

Abstract: A temperature detection apparatus and a rotation angle detection apparatus are provided that allow a temperature of a resolver to be calculated in real time. A rotation angle detection apparatus (10) (temperature detection apparatus) includes a resolver (20) with an excitation coil and output coils wound thereon, the excitation coil being subjected to an excitation voltage (VA) and the output coil outputting voltage signals (VB, VC) corresponding to the excitation voltage (VA), and a temperature calculation circuit (sensor microcomputer (32)) that detects a phase of the excitation voltage (VA) and that detects a phase of an excitation current (IA). The temperature calculation circuit (sensor microcomputer (32)) calculates a temperature of the resolver (20) based on a phase difference between the excitation voltage (VA) and the excitation current (IA).

Abstract: A controller and a laser processing device having the controller, capable of reducing time for switching feedback control to gap control, and capable of moving a processing nozzle relative to a workpiece so that an amount of change in acceleration when switching is minimized. The controller has: a deceleration start distance calculating part which calculates a deceleration start distance corresponding to a distance between the nozzle and the workpiece when deceleration of approach motion of the nozzle is started; a first velocity command generating part which generates a first velocity command value based on the deceleration start distance, a predetermined maximum approach velocity and deceleration rate; a second velocity command generating part which generates a second velocity command value based on a gap target value and a feedback value; and a velocity command switching part which selects one of the first and second velocity command values.

Abstract: In a system for compensating dynamic and thermal deformity errors of a linear motion single-plane gantry stage in real time, a stage apparatus using the system, and manufacturing, measuring, and inspecting apparatuses using the system, the system includes: a first two-dimensional position measuring unit arranged in each of two linear edge beams respectively positioned in both sides of the linear motion single-plane gantry stage for measuring the position of an X-axially movable gantry beam to provide a feedback of an X-axial motion thereof; a second two-dimensional position measuring unit for measuring the position of a Y-axially movable slider movable on the X-axially movable gantry beam to provide a feedback of a Y-axial motion thereof; a thermal fixing point provided as a thermal reference for measuring a thermal expansion of the X-axially movable gantry beam; and a compensation control unit for controlling an error motion of the linear motion single-plane gantry stage in real time by measuring dynamic and

Abstract: In an abnormality detection system for a rotation angle sensor, a fact that an abnormality has occurred in one of sine signals (S1, S2) or in one of cosine signals (S3, S4) is detected based on a sum of the electrical signals (S1, S2), and a sum of the electrical signals (S3, S4) (first detection result). A fact that an abnormality has occurred in one of the positive sine and cosine signals (S1, S3) or in one of the negative sine and cosine signals (S2, S4) by comparing a first temperature computed using a correlation between an amplitude and a temperature and based on the electrical signals (S1, S3), a second temperature computed using a correlation between the amplitude and a temperature and based on the electrical signals (S2, S4), and a third temperature detected by a temperature sensor with each other (second detection result). A microcomputer identifies which of the electrical signals is abnormal by comparing the first and second detection results with each other.

Abstract: In an abnormality detection system for a rotation angle sensor, a fact that an abnormality has occurred in one of sine signals (S1, S2) or in one of cosine signals (S3, S4) is detected based on a sum of the electrical signals (S1, S2), and a sum of the electrical signals (S3, S4) (first detection result). A fact that an abnormality has occurred in one of the positive sine and cosine signals (S1, S3) or in one of the negative sine and cosine signals (S2, S4) by comparing a first temperature computed using a correlation between an amplitude and a temperature and based on the electrical signals (S1, S3), a second temperature computed using a correlation between the amplitude and a temperature and based on the electrical signals (S2, S4), and a third temperature detected by a temperature sensor with each other (second detection result). A microcomputer identifies which of the electrical signals is abnormal by comparing the first and second detection results with each other.

Abstract: A detection signal receiving unit receives, via signal lines, a detection signal output from a position detector which is used in a motor control device. The resistance value of a termination resistor unit is changed to a resistance value determined depending on the type of the position detector in accordance with the received detection signal and the reference value determined depending on the type of the position detector.

Abstract: An encoder includes a measurement target which is coupled to a motor, a module which is positioned relative to the measurement target and generates signals based on motion of the measurement target, and a control device which generates and outputs position data based on the signals from the module and includes a position detector, an abnormality detector, a cause analyzer, a non-volatile memory, and a non-volatile memory controller. The position detector detects a position of the motor, the abnormality detector detects an abnormality based on state information including a state of the position detector, the cause analyzer analyzes the state information when the abnormality detector detects the abnormality such that a cause of the abnormality detected by the abnormality detector is identified, and the non-volatile memory controller stores in the non-volatile memory a result of analysis obtained by the cause analyzer.

Abstract: A valve actuator having a drive shaft, which, in use, is configured to adjust a valve between an open position and a closed position, an AC induction motor for driving the drive shaft a contactless position sensor configured to, in use, output a signal representing an angular position of the drive shaft or the valve, and a controller configured to control the AC motor in accordance with the signal output by position sensor.

Abstract: A method for measuring the displacement of a planar motor rotor. The measuring method comprises: four magnetic induction intensity sensors are distributed on the planar motor rotor; sampled signals of the four distributed sensors are processed to obtain signals Bsx, Bcx, Bsy and Bcy and magnetic field reference values Bksx, Bkcx, Bksy and Bkcy; and X-direction displacement and Y-direction displacement can be measured respectively according to inequalities (I) and (II) by judgments, wherein ?x and ?y are X-direction displacement resolution and Y-direction displacement resolution respectively, and BM is the magnetic induction intensity amplitude of the magnetic field of said planar motor. The method provided by the invention is simple in calculation, can avoid calculation of a transcendental function and solve the quadrant judgment problem, is favorable to real-time high-speed operation and has a high engineering value.

Abstract: Apparatus for controlling and diagnosing a prime mover of a vehicle traction system includes an alternator having a rotor and coupled to a crankshaft of the prime mover, a source of electrical energy, a position sensor supplying a position signal representative of an angular position of the rotor, and a control computer. The computer supplies energy to the alternator to crank the prime mover at a controlled rate. In a diagnosis mode, the computer generates a condition signal indicative of a malfunction of the prime mover, from a compression signal derived from an acceleration signal which is derived from the position signal. In a barring-over mode, the computer also supplies energy to the alternator and monitors the position signal to place the crankshaft in a desired angular position in an operation separate from diagnosis mode.

Abstract: An electrical machine includes a stator having a stator winding and a secondary transformer coil. A rotor is operatively connected to rotate relative to the stator, wherein the rotor includes a plurality of embedded permanent magnets. A primary transformer coil is wound on the rotor and is operatively connected to form a rotating transformer with the secondary transformer coil. An inverter/active rectifier component is operatively connected to the stator winding and the secondary transformer coil to control the stator winding based on a sense in the secondary transformer coil received from the primary transformer coil.

Abstract: A method is provided of calibrating a position sensor of an electric motor of a vehicle.

Abstract: A positioning control system for positioning a moving element on a basis of position command data is provided with a feedback loop. The system is also provided with a loop gain modifier for determining a loop gain, which is to be used in a following positioning operation, on a basis of a difference between an amount of overshoot measured in a current positioning operation and a predetermined tolerance or on a basis of a difference between an amount of overshoot measured in a current positioning operation and a first predetermined tolerance and a difference between an amount of undershoot measured in the current positioning operation and a second predetermined tolerance. The first and second tolerances may preferably be the same in absolute value. The moving element may specifically be a steerable mirror for drilling holes in a work by reflecting a laser beam. Also disclosed is a laser drilling machine including the system.

Abstract: A method of estimating an initial rotor position of a switched reluctance (SR) machine having a rotor and a stator is provided. The method may comprise the steps of driving a phase current in each of a plurality of phases of the SR machine to a predefined limit, performing an integration of a common bus voltage associated with each phase, determining a flux value for each phase based on the integrations, and determining the initial rotor position based on the flux values.

Abstract: A pulse signal output unit sends three-phase pulse signals according to movement of the movable member. A counter unit adds a first predetermined value or a second predetermined value to a count value or subtracts the first predetermined value or the second predetermined value from the count value, according to a combination of the pulse signals appearing when all the pulse signals are normal and a combination of the pulse signals appearing when one of the pulse signals malfunctions. A position detection unit detects the position of the movable member according to the count value.

Abstract: A method for allowing a controller of a transmission to learn a reference position of the transmission and a vehicle for which this method can be executed. By the method, when the shift lever is subjected to a predetermined input operation, the controller starts learning a reference position (for example, the gear end, the synchronization end, or the clutch engagement position) of the transmission.

Abstract: Hobby servo motor linear actuator systems are provided. In certain circumstances, a linear actuator system includes a lead screw attachment mechanism and a lead nut. The lead screw attachment mechanism is configured to be rotatably connected to an output shaft of a hobby servo motor assembly. The lead nut is configured to move linearly along the lead screw attachment mechanism as it is rotated. The system is optionally either open-looped or closed-loop. The lead screw attachment mechanism has an outer surface that can include multiple different types of threads such as, but not limited to, gear teeth and screw threads. The hobby servo motor assembly may include one hobby servo motor or multiple hobby servo motors that work together.

Abstract: In order to track the position of a component driven by an electric motor, wherein rotational movements of the electric motor are detected and used for a position count, deviations from an anticipated position count are determined and added to the position given by the position count as an uncertainty region.

Abstract: The invention relates to a positioning system which is suitable for micrometric regulating valves. The invention comprises a micro-regulating valve which is connected to the shaft of a servomotor by a flexible coupler and which is fixed to the same using a support. The aforementioned motor is, in turn, coupled to a potentiometer which transmits the position of the shaft of the motor and, consequently, of the rod of the valve to a control system which compares a signal received from an external control system with the position of the value, the position of the valve being corrected with a movement of the motor. In this way, a quick and precise positioning system can operate at high pressures and with very low flow rates.

Abstract: Hobby servo motor linear actuator systems are provided. In certain circumstances, a linear actuator system includes a lead screw attachment mechanism and a lead nut. The lead screw attachment mechanism is configured to be rotatably connected to an output shaft of a hobby servo motor assembly. The lead nut is configured to move linearly along the lead screw attachment mechanism as it is rotated. The system is optionally either open-looped or closed-loop. The lead screw attachment mechanism has an outer surface that can include multiple different types of threads such as, but not limited to, gear teeth and screw threads. The hobby servo motor assembly may include one hobby servo motor or multiple hobby servo motors that work together.

Abstract: An exemplary stage apparatus has a motor, stage, and position-measuring device. The motor has a planar stator and moving-coil mover (planar motor). The stator is a checkerboard magnet array extending in an x-y plane and producing a magnetic field having a field period of 2? in a u-v coordinate system rotated 45° from the x-y coordinate system of the plane. The stage, coupled to the mover, moves with corresponding motions of the mover relative to the stator. The position-measurement device includes a first group of four magnetic-field sensors that are movable with the stage. The sensors are situated at integer multiples of ?/2 from each other in u- and v-directions of the u-v coordinate system. The sensors produce respective data regarding a respective component of the magnetic field at, and hence the position of, the respective sensor within the period of the magnetic field.

Abstract: Provided are a device and method of stopping an induction motor. The includes: a frequency commanding unit for generating an operating frequency corresponding to a rotational speed command of the induction motor; a q-axis and d-axis V/F converter for outputting a first q-axis voltage (Vq1) proportional to the generated operating frequency and a first d-axis voltage (Vd1) proportional to a 0 frequency; a q-axis PI current controller for outputting a second q-axis voltage (Vq2) for stopping the induction motor when the operating frequency reaches a stopping frequency; a d-axis PI current controller for outputting a second d-axis voltage (Vd2) for stopping the induction motor when the operating frequency reaches the stopping frequency; and a selection unit for selecting and outputting the first q-axis and d-axis voltages (Vq1 and Vd1) or the second q-axis and d-axis voltages (Vq2 and Vd2) according to the operating frequency generated by the frequency commanding unit.

Abstract: A rotating electromechanical machine has a rotor having at least one current-carrying winding and at least one rotor-mounted sensor configured to sense a machine property or parameter during machine operation. Rotor-mounted circuitry dynamically modifies at least one property of the current-carrying winding during machine operation in response to the sensed machine property or parameter.

Abstract: An SEA architecture for controlling the torque applied by an SEA that has particular application for controlling the position of a robot link. The SEA architecture includes a motor coupled to one end of an elastic spring and a load coupled to an opposite end of the elastic spring, where the motor drives the load through the spring. The orientation of the shaft of the motor and the load are measured by position sensors. Position signals from the position sensors are sent to an embedded processor that determines the orientation of the load relative to the motor shaft to determine the torque on the spring. The embedded processor receives reference torque signals from a remote controller, and the embedded processor operates a high-speed servo loop about the desired joint torque. The remote controller determines the desired joint torque based on higher order objectives by their impedance or positioning objectives.

Abstract: A feedback system for controlling a servo motor comprising at least one rotary angle sensor and at least one rotary speed sensor, wherein the rotary angle sensor supplies a measured rotary angle value to a computer, wherein the rotary speed sensor supplies a measured rotary speed value to the computer, the actual rotary speed values are the measured rotary angle values interpolated according to the integrated measured rotary speed values, and wherein at high rotary speeds, the actual rotary speed values are the calibrated measured rotary angle values, differentiated with respect to time, and at low rotary speeds, the actual rotary speed values are the measured rotary speed values.

Abstract: A turning drive control apparatus that controls a drive of a turning mechanism of a construction machine driven to turn by an electric motor, includes: a drive command creation part that creates a drive command to drive the electric motor based on an amount of operation input through an operation part of the construction machine; a turning motion detection part that detects a turning motion of the turning mechanism; and a drive command correction part that corrects the drive command, when a turning motion in a direction opposite to a turning operation direction input to the operation part is detected by the turning motion detection part, to suppress the turning motion in the direction opposite to the turning operation direction in response to a degree of the turning motion in the direction opposite to the turning operation direction.

Abstract: Provided is a method of obtaining an image of a disc, in which the method obtains an image of an analysis or test result object of a disc by minimizing a difference between the positionings of a magnet of the disc and a magnet of a feeding unit, and an apparatus for driving a disc, wherein the apparatus performs the method. The method includes: fixing a positioning of a disc by using magnetic attraction between a first magnet installed on the disc and a second magnet installed on a feeding unit; minimizing a difference between the positionings of the first and second magnets; and obtaining an image of an analysis or test result object of the disc.

Abstract: A cycle counter generates a cycle signal which indicates, in the form of a digital value, the cycle of Hall signals H+ and H? that indicate the position of a rotor of a motor to be driven. An up/down counter repeatedly alternates between counting “up” and counting “down” upon detecting phase transitions that occur in the Hall signals, and generates a digital driving waveform signal having a sloping region the slope of which is set according to the cycle signal. A D/A converter receives the driving waveform signal, and converts the driving waveform signal thus received into an analog voltage. A driving unit supplies a driving voltage to the motor according to the analog voltage thus received.

Abstract: A pulse generating device includes a rotatable disc having a plurality of patterns that are formed on a surface of the rotatable disc in a circumferential direction of the rotatable disc, and three pulse generators to each detect the plurality of patterns formed on the rotatable disc and to respectively generate three pulse signals each corresponding to a rotational speed of the rotatable disc based on the detected patterns. The three pulse generators are evenly spaced at intervals of 120 degrees of angle with respect to a rotational axis of the rotatable disc in the circumferential direction of the rotatable disc.

Abstract: A pulse signal output unit sends three-phase pulse signals according to movement of the movable member. A counter unit adds a first predetermined value or a second predetermined value to a count value or subtracts the first predetermined value or the second predetermined value from the count value, according to a combination of the pulse signals appearing when all the pulse signals are normal and a combination of the pulse signals appearing when one of the pulse signals malfunctions. A position detection unit detects the position of the movable member according to the count value.

Abstract: An integrated gearbox/encoder and control system that includes: a gearbox with an output shaft connected to a mechanical load; a first sensor detecting the rotary position of the output shaft; a motor; a second sensor detecting the rotary position of the motor; and a system controller controlling motive drive to the motor. The two rotary position sensors permit direct determination of gearbox backlash which can be used in motor control. A drive current sensor similarly permits determination of a vibration signature for comparison with a standard.

Abstract: Implementations of actuators and capacitor-based position sensors for monitoring and controlling positioning of the actuators are provided, including implementations of actuators that use flexures to provide support to actuators and pivoting mechanisms to the actuators. Such actuators can be electromagnetically activated actuators that include a magnet stator and a coil rotor mounted on a flexure. A positioning sensor, such as a capacitor sensor, is provided to measure and monitor positioning of the actuator and is coupled to a feedback circuit which uses the measured positioning of the actuator to control the actuator.

Abstract: A system for controlling a motorized track light system constrained to travel along a track has a control unit coupled to a motor that causes the track light system to move along the track, a plurality of stop sensors strategically disposed along the track, a sensor activation device located on the track light system, the sensor activation device positioned to interface with the stop sensors, and a light sensor for detecting ambient light of a preset level. The system detects a preset level of ambient light, initiating power to the motor of the track light system, moving the lights along the track until the activation device interfaces with a first of the plurality of stop sensors, stopping movement of the track light system along the track for a preset period of time, and at the end of the preset time period, the electrical power is restored to the motor moving the track light assembly along the track to the next of the plurality of stop sensors.

Abstract: A manipulator, in particular a small robot, has at least two motor mutually movable limbs with a motion axis of both limbs being acted on by an axle drive that has an external rotor motor, a position transmitter and a transmission. The transmission has at least one planetary gear set with a center gear and at least one planet meshing with it that also meshes with a ring gear and is mounted on a planet carrier. One of both limbs of the manipulators is torque proof connected with the ring gear and is mounted by this radial and/or axially, and the other is torque proof connected by both limbs of the manipulator with the planet carrier and is mounted by this radial and/or axially.

Abstract: The present invention is a positioning work stop for use with a machine tool for and having a signaling means that operates as a placement indicator effective for providing a signal if the work piece to be machined is in its proper position for machining or for signaling if the work piece has shifted out of position for machining. In a preferred embodiment of the invention the positioning work stop comprises a stop member having a stop surface, a switch element, a signaling means, and a power supply that are electrically coupled such that the signaling means activates when the work piece makes contact with the stop surface and operates as a placement indicator effective for providing a signal if the work piece to be machined is in its proper position for machining or for signaling if the work piece has shifted out of position for machining.

Abstract: A method of processing a resolver fault in a motor generator unit (MGU) includes receiving a position signal from a resolver describing a measured angular position of a rotor of the MGU, determining the presence of the resolver fault using the position signal, and calculating or extrapolating an estimated rotor position when the resolver fault is determined. A predetermined resolver fault state may be determined using a measured duration of the resolver fault, and the MGU may be controlled using the estimated rotor position for at least a portion of the duration of the resolver fault. A motor control circuit is operable for processing the resolver fault using the above method, and may automatically vary a torque output or a pulse-width modulation (PWM) of the MGU depending on the duration of the resolver fault.

Abstract: Multi-rotation hobby servo motors are provided. In one embodiment, a hobby servo motor comprises a rotatable output shaft, a feedback mechanism, and a control circuit. The feedback mechanism generates a feedback signal that is indicative of rotation of the rotatable output shaft, and the control circuit utilizes the feedback signal to generate a control signal for the rotatable output shaft. The feedback mechanism is optionally an encoder such as, but not limited to, a magnetic encoder, an optical encoder, a rotary encoder, or a linear encoder.

Abstract: Systems, devices, and methods for controlling a motor are disclosed. A method may include determining a rotational direction of a motor from a pair of quadrature signals sent to a microprocessor. The method further includes adjusting an internal count stored in the microprocessor at each edge of each of the pair of quadrature signals. The method further includes adjusting an external count stored in the microprocessor and transmitting an interrupt to a main controller after the first phase signal and the second phase signal have transitioned through each combinational logic state in one of a forward rotational direction and a reverse rotational direction. The method further includes transmitting a signal comprising the rotational direction of the motor and the external count from the microprocessor to a main controller.

Abstract: The rotation period of a motor is subdivided by edge interval times and a rate of change between a currently calculated edge interval time and an edge interval time calculated one rotation of the motor previously is calculated at the detection of each edge. Then the rotation period of the motor is calculated by multiplying a set reference period by the calculated rate of change.

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: 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: A method for protecting an electronic apparatus driven by a DC motor and a detection circuit for detecting positioning signals thereof. The electronic device includes an optical encoder, a code strip, and a DC motor. While moves along the code strip, the optical encoder outputs a first positioning signal and a second positioning signal for the control of the DC motor. The method includes the steps described below. First, states of the first and second positioning signals are detected. If the states of the first and second positioning signals are normal, the DC motor is controlled according to the first and second positioning signals. If the first positioning signal or the second positioning signal is abnormal, a preventive method is performed.

Abstract: A stator position adjustment method for a motor drive device that includes a motor case, a rotor shaft supported by the motor case in order to rotate a rotor inside the motor case, and a stator disposed at an outer circumference of the rotor concentrically with the rotor and having a configuration in which the stator is tightened and secured to the motor case by a tightening unit that tightens the stator along a rotor axis. The method includes the steps of setting a first tolerance range as a maximum tolerance range of a stator axis in which a first gap is formed between an outer circumference surface of the stator and an inner circumference surface of the motor case; measuring a position of the stator axis; and adjusting the position of the stator axis within the first tolerance range based on a measured position of the stator axis.

Abstract: Circuits and methods to read out capacitive sensors for distance measurement used by a position control system having a high accuracy and low noise have been disclosed. The ratio or difference of the capacitances of two sensor capacitors is used to determine the distance of an object from a target position. A sense amplifier is using auto-zero methods to achieve a long term stability. A sample-and-hold circuit using double correlated sampling methods minimizes noise. Low cost capacitors can be used with the sample-and-hold circuit because not the absolute value of capacitances but only the ratio of capacitances are relevant. A high resolution is ensured also by significant over-sampling of the control loop.

Abstract: A calibration method for servo is provided, wherein a motor of the servo is activated at a low-speed mode to drive a moved member of the servo moving to a first limit position and a second limit positions. During the movement of the moved member, a motor control power of the motor is monitored continuously to determine whether the motor control power exceeds a threshold value. When the moved member reaches the first or the second limit position, the motor control power is raised to exceed the threshold value and a motor coordinate value corresponding to the first or second limit position is determined simultaneously. Finally, a conservation relation for determining the actual coordinate by the motor value can be derived according to the values of actual coordinate of the first and second limit positions, and the values of the corresponding motor coordinate.