Abstract: An improved technique for controlling an electro-mechanical actuator combines a sliding mode of control with a second mode of control. An error signal is generated based on the difference between an input position signal and a feedback position signal. When the error signal is above a predetermined threshold, the actuator is controlled in the sliding control mode. When the error signal is below the predetermined threshold, the actuator is controlled in the second control mode. The combination of the sliding control mode with the second control mode yields a robust controller that can tolerate large parameter variations and uncertainties without sacrificing precise steady state tracking.

Abstract: The invention related to a control system for a mill, particularly a roller grinding mill, comprising a mill control device (11), which is designed to control at least one mill characteristic on the basis of an associated target variable, and a fuzzy-control device (13), which is connected to the mill control device (11) and designed to adjust the target variable of the at least one mill characteristic to be controlled when at least one operating parameter of the mill deviates from a predefined normal range as a function of fuzzy rules that are based on said at least one operating parameter of the mill until the at least one operating parameter of the mill has reached the predefined normal range again. A solution is to be provided, which enables automated optimized mill operation even with changing operating conditions, particularly a mill operation that prevents the “mill rumbling”.

Abstract: A power supply circuit for an electric motor, the circuit comprising a plurality of inverter bridge arms, each having means for connection to a respective winding of the motor, each inverter bridge arm comprising in series a first insulated gate bipolar transistor and a junction field effect transistor that are connected to a controller, the circuit including a second insulated gate bipolar transistor connected in series with each field effect transistor and connected to the controller, and a damping resistor connected in parallel with the second bipolar transistor. An aircraft flight control member including a movable airfoil associated with at least one drive motor connected to such a power supply circuit.

Abstract: A multi-drive printed product processing device is provided that includes a processing component and a motor driving the processing component. A motor control controls the motor. An encoder measures a position of the motor and sends an encoder feedback signal indicating the position. The motor control receives the encoder feedback signal. An encoder feedback signal verification circuit verifies the integrity of the feedback signal.

Abstract: A control loop circuit for use in a closed-loop control system that controls a system such as a linear motor is presented. The control loop circuit includes a lead-lag compensator that features a lead compensation network configured to reduce output noise without substantially changing the effect of the lead compensation in the control system's frequency response.

Abstract: A vibration control robot system of the present invention includes: a robot controller (101) transmitting an operation command value and receiving an output value of a pulse encoder of the servo motor, wherein the robot controller includes a controller-side communication unit (5) which transmits the operation command value and the output value of the pulse encoder to a robot vibration controller; and the robot vibration controller (11) including: an acceleration sensor interface (15); a corrected operation command value calculation unit (13) which calculates a corrected operation command value obtained so as to suppress vibration of the robot; and a vibration-controller-side communication unit (12) which transmits the corrected operation command value to the robot controller (101), wherein the robot vibration controller (11) is arranged independently of the robot controller (101).

Abstract: A vehicle damper including an electromagnetic damper configured to generate a damping force with respect to a motion of a sprung portion and an unsprung portion toward each other and a motion thereof away from each other and includes: an electromagnetic motor; a motion converting mechanism; and an external circuit which is disposed outside the electromagnetic motor and including a first connection passage and a second connection passage and which includes a battery-device connection circuit for connecting the motor and a battery device and a battery-device-connection-circuit-current adjuster configured to adjust an electric current that flows in the battery-device connection circuit, wherein the damper system further includes an external-circuit controller configured to control an electric current that flows in the electromagnetic motor by controlling the external circuit and configured to control a flow of an electric current between the battery device and the electromagnetic motor by controlling the battery

Abstract: In a method and device for monitoring a movement-controlled machine, such as a manipulator, having an electronically commutated drive motor for which a commutation angle is provided based on its detected real position and a control variable, in particular a predetermined desired position, a limit value is determined for a rate of change in particular a time derivative of the real position of the drive motor, and the commutation angle is predetermined such that the rate of change of the commutation angle does not exceed a limit value.

Abstract: A motor control device that controls motion of a control target including a motor and a vibratable element includes a generating unit configured to generate, according to state information representing a state of the control target related to a vibration characteristic of the control target, a first parameter representing the vibration characteristic of the control target, a first calculating unit configured to calculate a second parameter corresponding to a temporal change amount of the first parameter generated by the generating unit, a second calculating unit configured to calculate, using a motion target value, the first parameter, and the second parameter, model torque such that the control target does not excite vibration, and a developing unit configured to develop, according to the model torque calculated by the second calculating unit, a torque command such that the motion of the control target follows the motion target value.

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: Provided is a technique to suppress hunting in a range of a minimum resolution of a pulse encoder when a servo motor has reached a target position and stopped, thereby maintaining a stable stop state. A servo motor position control device uses a cascade configuration having a position control loop as a main loop and a velocity and current control loop as a minor loop. A proportion control is performed for a position control while a proportion integration control is performed for a velocity control and a current control. When the servo motor position has reached the target position and stopped (S201), a current instruction value for the current control is maintained at a value upon stop (S202) and the current control is switched to the proportion control (S204).

Abstract: A damping apparatus for an automobile is provided, capable of ensuring a high level of reliability while obtaining excellent damping effect with simple configuration. The damping apparatus for an automobile that reduces vibrations of an automobile body may include an actuator that is attached to the automobile body and drives an auxiliary mass; a current detector that detects a current flowing through an armature of the actuator; a section that detects a terminal voltage applied to the actuator; a calculation circuit that calculates an induced voltage of the actuator, and further calculates at least one of the relative velocity, relative displacement, and relative acceleration of the actuator, based on a current detected by the current detector and the terminal voltage; and a control circuit that drive-controls the actuator based on at least one of the relative velocity, relative displacement, and relative acceleration of the actuator calculated by the calculation circuit.

Abstract: A motor is driven based on an axis current value in a rotating coordinate system that rotates in accordance with a control angle that is a rotational angle used in a control. The control angle is calculated by adding an addition angle to an immediately preceding value of the control angle in each predetermined calculation cycle. A command steering torque is set based on a predetermined steering angle-torque characteristic. The addition angle is calculated based on the deviation of a detected steering torque from a command steering torque. The addition angle based on the deviation is changed when a predetermined condition is satisfied.

Abstract: A quasi-translator for economically producing pure, smooth translational motion with broad arcuate or error-free motion regardless of orientation, which is useful in numerous interferometer applications including spectroscopy, a Fourier modulator and a Fourier spectrometer are provided. The quasi-translator utilizes a support, an arm including a driving magnet on a first end and a driven element on a second end, an axis for rotation of the arm, a bearing system that controls the rotation of the arm about the axis, a drive coil and a drive amplifier to drive the arm in the arcuate motion. The quasi-translator may be employed in a Fourier modulator to change the optical path difference of the interferometer/quasi-translator at a substantially constant rate of change. The quasi-translator and/or Fourier modulator may be used in a Fourier spectrometer to create an optical spectrum from a light beam and/or electrical signal created from the light beam.

Abstract: A machine tool includes a main axis 30 to which a touch probe 17 is attached, a motor 15 that rotationally drives the main axis 30, a rotation angle position detector 16 that detects a rotation angle position of the motor 15, and a control device 20. The control device, when a measurement mode command for performing measurement of a workpiece by the touch probe 17 is input, multiplies a d-axis current command value Idc by a d-axis current correction coefficient K that is less than 1 to reduce the d-axis current command value Idc to a d-axis current command correction value Idc?, using a d-axis current command correction section 4. Thus, in the machine tool, small rotation vibrations of the main axis, generated when rotating the main axis to which the probe is attached and performing measurements of a workpiece, can be suppressed to thereby increase the measurement accuracy.

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: The invention relates to a method for absorbing the displacement, under the influence of an external force, of at least one plunger (10,20) in a linear electrodynamic motor comprising a least an induction coil (11, 21) magnetically coupled with the plunger. Said method comprises the steps of: detecting in said induction coil a current induced (I?ind) amplified relative to the induced current. The invention can be applied to cryogenic machines on board space ships.

Abstract: An electric power supply system has a power bus for providing DC power, and a control unit for a source of power to supply the power bus. The power unit includes a damping algorithm to provide damping to power supplied on the power bus. A motor and a motor control include a compensation block for tapping power from the bus, and identifying a portion of a supplied signal due to the damping. The compensation block provides a signal to a summing block that addresses the damping on the power bus prior to the power being supplied to the motor. A method of utilizing such a system is also disclosed.

Abstract: There are provided: a plurality of notch filters which are arranged inside a control system for feedback-controlling a moving operation of a moving section of a motor and attenuate signal components having near frequencies with a notch frequency at a center in an input signal; a plurality of oscillation extracting filters which are set with different frequency bands as being corresponded to the respective notch filters and extract oscillating components in the set frequency bands from a speed detection signal; and a plurality of notch controlling sections which are arranged with respect to the respective oscillation extracting filters and control the notch frequencies of the corresponding notch filters so as to decrease amplitudes of the oscillating components extracted by the oscillation extracting filters.

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: The invention relates to a motor arrangement (1) comprising a motor (4) on which a transmitter device (6) is arranged, a regulating device (2) which is spatially separated from the motor, communicates with the motor (4) via at least one motor line/connection line (10), and controls the movement of the motor, and at least one sensor device (8) which is arranged on the motor (4), detects at least one physical property of the motor, and emits a signal characterising said physical property, the transmitter device (6) being connected to the regulating device (2) via the connection line. According to the invention, there is a direct communication connection (9) between the sensor device (8) and the transmitter device (6), by which means the sensor device (8) transmits the characteristic signal directly to the transmitter device (6).

Abstract: A sensor system for providing control of an electric motor having an inductive angle sensor system including a first inductive coil configured for affixation to a rotor shaft of the electric motor wherein rotation of the rotor shaft causes corresponding rotation of the first inductive coil. A second inductive coil fixedly mounted in spaced relationship to the first inductive coil. An evaluation circuit coupled to the second inductive coil and to the electric motor operative to determine a rotor shaft angle for the rotor shaft of the electric motor through evaluation of an induced magnetic field between the first and second inductive coils.

Abstract: A DC-motor (46) actuates a highly-reduced reduction gear of an actuating drive for a flap or valve in order to regulate a gas or liquid volume flow, particularly for heating/ventilation/climatization, or fire or room protection. Current flow in the stator coils (A, B, C) is commutated in a program-controlled manner without integrated position sensors. Algorithms enable counting rotations of rotor (54) of the DC-motor (46). Problems related to the principle of motor rotation speed at low rpm are prevented. The DC-motor (46) includes a stator (44) having three stator coils (A, B, C) which extend over 3n stator poles (52), and an annular-shaped permanent magnet rotor (54) having 2m permanent magnet segments with alternating polarity (N, S), a coaxial cup-shaped external rotor (110) and a coaxial drive shaft (108), whereby n and m are whole multiplication factor numbers (1, 2, 3, 4) and are different from each other.

Abstract: A swing drive system for an upper structure of a machine includes an electric motor that receives electrical power and a torque command signal. A sensor provides a sensor signal indicative of a swing speed. An electronic controller provides the torque command signal to the electric motor in response to the command signal by receiving the command and sensor signals, providing the torque command signal to maintain a swing motion of the upper structure during a normal operating state, and providing the torque command signal based on the sensor signal to brake the swing motion at a substantially constant rate when the command signal is indicative of a zero desired swing speed during a braking operating state.

Abstract: A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

Abstract: A machine control device has a position regulator configured to enable modification of the proportional gain during regulation operations, and has proportional gain setting unit, which sends an instruction to modify the proportional gain to the position regulator based on a position instruction value which is an output of a position instruction unit. In the proportional gain setting unit, when the movement velocity based on the position instruction value from the position instruction unit decreases, that is, when the position instruction value is a value at which the movement distance is short, the proportional gain of the position regulator is set high, and when the movement velocity based on the position instruction value increases, that is, when the position instruction value is a value at which the movement distance is long, the proportional gain is set low.

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 discloses a chip structure capable of smoothing slope of signal during conversion. And the chip structure is suitable for a DC motor which is embedded in a portable electronic device. The DC motor is for adjusting the focal distance of a digital camera which is installed within the portable electronic device. The chip structure comprises an input terminal, a first converter, a control unit, a second converter, an amplifier circuit and an output terminal. The input terminal is for receiving a first digital signal. The first converter is for converting the first digital signal into an analog signal. The control unit is for elongating the transform time of the analog signal. The amplifier circuit is for amplifying the elongated analog signal. The second converter is for converting the elongated analog signal into a second digital signal. And the output terminal outputs the second digital signal.

Abstract: A control loop circuit for use in a closed-loop control system that controls a system such as a linear motor is presented. The control loop circuit includes a lead-lag compensator that features a lead compensation network configured to reduce output noise without substantially changing the effect of the lead compensation in the control system's frequency response.

Abstract: A method and a system for video camera assembly are provided. The video camera assembly includes at least one of a pan mechanism rotatable about a pan axis and a tilt mechanism rotatable about a tilt axis. The pan mechanism includes a pan motor and a pan position encoder. The tilt mechanism includes a tilt motor and a tilt position encoder. A controller is communicatively coupled to at least one of the pan mechanism and the tilt mechanism and is configured to apply a filter to a power drive signal of at least one of the pan motor and the tilt motor based on a determined corresponding rotational speed of the at least one of the pan motor and the tilt motor with the effect of reducing steady state vibrations which degrade the visual and audible qualities of said video camera assembly.

Abstract: A control method is provided to reduce the spring resonance of a voice coil motor when the coil current of the voice coil motor is changed. Each time a total variation for the coil current to be changed is identified and divided into a plurality of step variations applied one by one with a time step equal to one half of the spring resonant period of the voice coil motor. Due to reduction of the spring resonance, the control method speed up the voice coil motor to a steady state. With this control method, a lens focusing system has a shorter focusing time.

Abstract: A host apparatus includes a command-pattern changing unit. A detector includes a detector-communication-parameter changing unit. A motor drive control apparatus includes a communication-parameter changing unit and a control-gain changing unit. The command-pattern changing unit, the detector-communication-parameter changing unit, and the communication-parameter changing unit change, based on determination of detector communication by a communication-abnormality determining unit, plural communication parameters, control gains, and command patterns, which are determined in advance, in synchronization with one another to control drive of a motor.

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: Suppression of vibration of a load machine without reducing the responsiveness of the load machine to an operation command is achieved by a method and an apparatus for controlling an inertial system intended to control an inertial system that has a motive power generator and a load machine that are coupled to each other via a torque transmission element. Acceleration command information that designates the acceleration of the load machine is multiplied by a predetermined gain to produce a vibration suppression control variable. The vibration suppression control variable is added to the position command to form a vibration suppression control command, and the inertial system is controlled according to the vibration suppression control command.

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 a control device for controlling a variable damper of a vehicle suspension system, when a stroke speed of the damper is within a range including a zero stroke speed, the target damping force is determined as a force opposing a current movement of the damper without regards to the direction of the target damping force determined by a target damping force determining unit. Thereby, even when the wheels move vertically at short intervals, the control value is prevented from changing rapidly, and this allows a damping force of an appropriate level to be achieved in a stable manner at all times. Also, the target damping force when a stroke speed of the damper is within a range including a zero stroke speed may be selected to be a relatively high value or low value so that a desired vehicle behavior may be achieved.

Abstract: A parallel mechanism includes a base portion, a bracket to which an end effecter is attached, a plurality of actuators attached to the base portion, a plurality of arms through which the plurality of actuators and the bracket are coupled together in parallel, and a control device arranged to control the actuators. When the end effecter in a stopped state is moved to a target position, the control device is arranged to control the actuators so that a level of acceleration at which the end effecter is accelerated is higher than a level of deceleration at which the end effecter is decelerated.

Abstract: In a method and device for monitoring a movement-controlled machine, such as a manipulator, having an electronically commutated drive motor for which a commutation angle is provided based on its detected real position and a control variable, in particular a predetermined desired position, a limit value is determined for a rate of change in particular a time derivative of the real position of the drive motor, and the commutation angle is predetermined such that the rate of change of the commutation angle does not exceed a limit value.

Abstract: A human-operated system comprises a positioning system and an input shaper. The positioning system moves an object from one location to another. The positioning system includes a computing device that controls the movement of the positioning system responsive to receiving a user command. The input shaper is coupled to the computing device of the positioning system. The computing device estimates an overtravel of the positioning system and determines an overtravel constraint that is factored into the movement of the positioning device. The computing device moves the positioning system based on the overtravel constraint in a manner that limits the overtravel, deflection and vibration of the object as the object is moved from one location to another. The human-operated system includes a predictive element that represents a predictor location responsive to the user command provided by the human operator, which aids the human operator position the positioning system.

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: A self-tuning vibration absorber including a carrier rod assembly having operatively connected thereto a mounting mechanism for mounting the carrier rod assembly to a primary system and a hollow shafted motorized tuning mechanism for tuning a phase difference between vibration of the primary system and vibration of the carrier rod assembly to 90 degrees, the carrier rod assembly further including a detecting mechanism for detecting the vibration of the primary system and the vibration of the carrier rod assembly, and a controller in electrical connection with the detecting mechanism and the tuning means for controlling the tuning mechanism based on the vibration of the primary system and the vibration of the carrier rod assembly detected. A method of vibration dampening, a method of controlling a self-tuning vibration absorber, and a method of reducing hunting motion in railcars.

Abstract: Radiofrequency device (30; 30?; 30?; 30??) controlling means for supplying at least one electrical load (14, 14?) and comprising a radiofrequency unit (11) of radiofrequency signals transmitter and/or receiver type and connected by a first conductor (9b) to the AC mains (9), wherein the radiofrequency unit comprises a radiofrequency signal output and/or input (20) connected by an HF link (19) to a first terminal (21) of a tuning circuit (17; 17?) of the radiofrequency device, this tuning circuit being: connected by a second terminal (22) to the first conductor, connected by a third terminal (23) to an electrical ground (GND) of the radiofrequency unit, furnished with means (L1, C1; L2, C3, C4) for blocking the conduction of radiofrequency signals on the first conductor between the second terminal and the third terminal, and traversed between the second terminal and the third terminal by the AC current (I-ACT) flowing in the first conductor and supplying said electrical load.

Abstract: A machine having a drive that directly or indirectly excites vibrations in the machine over a frequency range when the drive is connected to the power supply. A sensor detects a time-dependent signal that is characteristic of the excited vibrations. The time-dependent signal is transmitted to a control device that analyzes the frequency of the time-dependent signal and relates the frequency analysis to the excitation that produces the excitation and uses this relationship to determine a state of at least one element of the machine. The control device outputs a message to an operator of the machine on the basis of the state that is determined. Preferably, the control device applies an interference variable that has at least one frequency inside the frequency range to the drive so as to excite vibrations. The interference variable may be a sinusoidal interference variable whose frequency passes through the frequency range, or a pseudobinary interference variable whose spectrum covers the frequency range.

Abstract: An enhanced torque ripple mitigation algorithm for permanent magnet synchronous machines (PMSMs), the algorithm including compensation for sensor delay.

Abstract: A phase difference detection device able to detect a phase with a high precision is provided.

Abstract: A system for positioning an object, having a fixed base, a support for the object, an actuator for applying a force to displace the support relative to the fixed base, a sensor for measuring the load force on the support, and a controller for processing the measured load force to control the position of the support and/or damp at least one resonance frequency of the system. A method of controlling the system is also provided.

Abstract: A motor control system suppresses vibration of a machine base and achieves high-speed positioning without using a special sensor but using a model control system. A first feedback section outputs a first feedback command generated based on model machine base position information and containing at least position information on the machine base. A second feedback section outputs a second feedback command containing a filtered model torque command. A differential between the sum of the first feedback command and the second feedback command obtained by a second addition section and the model torque command is calculated to give the differential to an input portion of a model torque command low-pass filter and an input portion of a torque command low-pass filter.

Abstract: A metrology tool is arranged to measure a parameter of a substrate that has been provided with a pattern in a lithographic apparatus. The metrology tool includes a base frame, a substrate table, a sensor, a displacement system, a balance mass, and a bearing. The substrate table is constructed and arranged to hold the substrate. The sensor is constructed and arranged to measure a parameter of the substrate. The displacement system is configured to displace the substrate table or the sensor with respect to the other in a first direction. The bearing is configured to movably support the first balance mass so as to be substantially free to translate in a direction opposite of the first direction in order to counteract a displacement of the substrate table or sensor in the first direction.

Abstract: The present invention relates to a technology related to angle control and automatic parking, and more particularly to an angle control method and apparatus for improving angle control quality so as to make the movement of a steering handle smooth, and an automatic parking system using the same.

Abstract: Torsional oscillation of a shaft in a swing drive system of an excavator is minimized by monitoring torsional strain of the shaft. An electric motor provides torque to the shaft in response to a drive signal provided by a converter. A compensation circuit produces a compensation signal as a function of torsional strain of the shaft. A field excitation circuit or regulator powers a converter as a function of the compensation signal such that a counter torque is provided to the shaft and torsional oscillation of the shaft is reduced.