Abstract: A motor control system of a motor is provided. The system includes a state estimation observer that computes an estimated velocity based on an inertia-damping response to the dynamics of the motor shaft, a torque command signal, and the compensated command signal. This compensated signal comes from a proportional-integral-derivative (PID) controller that determines a difference between a sensed position and an estimated position. The estimated position is determined by the estimated velocity and an integrator. The control system may also include a motor-velocity based lowpass filter which applies a filter to the estimated velocity.

Abstract: As speed operation range identification system for motion systems driven by permanent magnet synchronous motors (PMSMs) or induction motors leverages both characteristics of the motor as well as dynamic characteristics of the motion system—including the friction and load—to identify suitable maximum speeds for operation of the motion system in the normal speed and field weakening regions. The identification system can model both motor characteristics as well as real-time dynamics of the controlled mechanical system that may vary during operation. The system can apply an optimization algorithm to this model to determine suitable maximum speeds for operation in the normal speed and/or field weakening regions. The determined maximum speeds can be used to perform substantially real-time adjustments to motion profile limits or current reference values generated by the motor controller in order to ensure that the speed of the system remains below the determined maximum.

Abstract: Methods and systems are provided for regulating engine operating parameters such as exhaust gas recirculation (EGR) based on road roughness conditions. Based on increased road roughness estimation, EGR flow rate may be opportunistically raised, enabling NVH associated with elevated EGR levels to be masked by NVH associated with rough road conditions. In addition, purging of fuel vapors from a canister or a crankcase to the engine may be increased while transmission shift schedules may be advanced so as to complete the shift during the rough road condition.

Abstract: Methods and systems are provided for regulating engine operating parameters such as exhaust gas recirculation (EGR) based on road roughness conditions. Based on increased road roughness estimation, EGR flow rate may be opportunistically raised, enabling NVH associated with elevated EGR levels to be masked by NVH associated with rough road conditions. In addition, purging of fuel vapors from a canister or a crankcase to the engine may be increased while transmission shift schedules may be advanced so as to complete the shift during the rough road condition.

Abstract: Methods and systems are provided for regulating engine operating parameters such as exhaust gas recirculation (EGR) based on road roughness conditions. Based on increased road roughness estimation, EGR flow rate may be opportunistically raised, enabling NVH associated with elevated EGR levels to be masked by NVH associated with rough road conditions. In addition, purging of fuel vapors from a canister or a crankcase to the engine may be increased while transmission shift schedules may be advanced so as to complete the shift during the rough road condition.

Abstract: Methods and apparatus are provided for a dithered EPS system of a vehicle. The apparatus includes a steering assembly having one or more sensors for sensing user steering input. A controller is responsive to the user steering input for providing a motor control signal. The apparatus also includes a dither signal generator providing a dither signal and a combiner for combining the motor control signal and the dither signal to provide a dithered motor control signal to control the motor of the apparatus. The methods include sensing user steering input via one or more sensors coupled to a steering assembly of a vehicle and generating a motor control signal responsive to the user steering input. A dither signal is generated and combined with the motor control signal to provide a dithered motor control signal that is used to control motor.

Abstract: According to one embodiment, a drive device comprises a first generating unit which moves in straightly movable manner or rotatable manner and generates precharge pressure, a sliding guide unit which has a sliding guide surface that comes into contact with a sliding surface of the first generating unit and to which the precharge pressure is given, a vibration unit which gives vibration to the first generating unit, and a second generating unit. When the vibration is given to the first generating unit, the second generating unit generates driving force for driving the first generating unit in a predetermined direction so that the driving force is more than frictional force between the sliding surface and the sliding guide surface. When the vibration is not given to the first generating unit, the second generating unit generates the driving force so that the driving force is less than the frictional force.

Abstract: A linear actuator associated with an actuator system for a device includes a wire cable fabricated from an active material. The linear actuator couples to the device and to the moveable element. The active material induces strain in the linear actuator in response to an activation signal. The linear actuator translates the moveable element relative to the device in response to the induced strain. An activation controller electrically connects to the linear actuator and generates the activation signal. A position feedback sensor monitors a position of the moveable element.

Abstract: According to one embodiment, a drive device comprises a first generating unit which moves in straightly movable manner or rotatable manner and generates precharge pressure, a sliding guide unit which has a sliding guide surface that comes into contact with a sliding surface of the first generating unit and to which the precharge pressure is given, a vibration unit which gives vibration to the first generating unit, and a second generating unit. When the vibration is given to the first generating unit, the second generating unit generates driving force for driving the first generating unit in a predetermined direction so that the driving force is more than frictional force between the sliding surface and the sliding guide surface. When the vibration is not given to the first generating unit, the second generating unit generates the driving force so that the driving force is less than the frictional force.

Abstract: A controller estimates Coulomb friction itself together with inertia and viscous friction, and reduces the influence of the Coulomb friction on the accuracy of the estimated inertia. In addition, the controller estimates inertia, viscous friction and Coulomb friction simultaneously with sequential adaptation in which a Fourier transformer is not used but an inverse transfer function model is used in order to minimize the estimated error. Data sampled for a predetermined time need not be accumulated, as a result, a large amount of data memory is unnecessary.

Abstract: One embodiment of a system and method for meeting end conditions of a path plan utilizing a path generator that continuously generates commands for a path plan while tracking the total time expired in the path plan. The path generator computes the time remaining in the path plan and substitutes the remaining time for the length of the final sample period in the path plan when the length of the remaining time is less than the length of a full sample period.

Abstract: In order to provide a driving device that is capable of eliminating sticking of a movable member due to nonuse, the driving device includes a drive shaft that reciprocates in axial directions with expansion and contraction of an electromechanical transducer element, a movable member that frictionally engages with the drive shaft, and a drive circuit that inputs drive voltage into the electromechanical transducer element, the drive circuit outputting drive operation pattern voltage having a frequency (fd1?) lower than a resonance frequency (fr) of the electromechanical transducer element and lower than a frequency (fd1) that maximizes moving velocity of the movable member and sticking elimination pattern voltage having a frequency lower than the frequency (fd1?) of the drive operation pattern voltage and in vicinity of a frequency (fd2) that maximizes thrust acting on the movable member.

Abstract: A linear stepper motor is used for the displacement of an armature parallel to a stator having N steps. The stator includes (N+2) stator pole pieces which are enclosed by a magnetic guiding element and are each approximately the same distance from neighboring stator pole pieces. Furthermore, at least one coil is located between two stator pole pieces. The armature is enclosed by the stator in the radial direction and has a permanent magnet magnetized parallel to the stator which is disposed between two armature pole pieces. As a result of the reluctance forces, the armature occupies stable idle positions inside the stator in which the stator pole pieces lie opposite the armature pole pieces. By energizing the coils with a short current pulse, the armature can be displaced inside the stator between the different stable idle positions.

Abstract: A linear motor for optical systems, for example, endoscopes, is described. The motor has a stator with a magnetic guiding member and two adjacently disposed coils which are energized in opposite directions. Furthermore permanent magnets polarized in opposite directions and in the axial direction are provided on both sides of the pair of coils. The armature of the motor comprises a permanent magnet which is polarized in the opposite direction to the permanent magnet of the stator and is connected to a pole piece at each end. The pole pieces are arranged so that in the rest position each pole piece lies at the centre of one of the coils. By applying current to the coil, the armature can be displaced from a rest position in the longitudinal direction.

Abstract: A linear motor for optical systems, for example, endoscopes, is described. The motor has a stator with a magnetic guiding member and a coil. The armature of the motor includes two permanent magnets which are of opposite polarity. A pole piece made of soft-magnetic material is provided between the permanent magnets. By applying current to the coil, the armature can be displaced from a rest position in the longitudinal direction.

Abstract: A controller estimates Coulomb friction itself together with inertia and viscous friction, and reduces the influence of the Coulomb friction on the accuracy of the estimated inertia. In addition, the controller estimates inertia, viscous friction and Coulomb friction simultaneously with sequential adaptation in which a Fourier transformer is not used but an inverse transfer function model is used in order to minimize the estimated error. Data sampled for a predetermined time need not be accumulated, as a result, a large amount of data memory is unnecessary.

Abstract: An apparatus, a method and a control system for controlling an industrial robot with at least one axis of rotation and/or translation. The robot includes at least one actuator or motor at each of the axes for driving a movement of an arm of the robot and at least one sensor at each of the rotatable shafts. A dither-signal generator for generation of a periodic signal is used to provide a varying dither signal to a servo of the actuator. Automatic adaption of the dither signal is provided. A computer program for carrying out the method and a graphical user interface.

Abstract: A system and control method mitigates hysteresis of an adjustable component in the system. A control module can allow small control changes to be effected to the component within limits of the component's and/or the system's normal hysteresis band. The control method can allow finer, more accurate and more aggressive control to be obtained from the component. The system and method can utilize two separate control regimes to control adjustments to the component. The first control regime can control changes larger than a hysteresis band and/or changes in a same direction as the last adjustment that was performed with the first control regime. The first control regime can be a feedback-based adjustment to the component. The second control regime can be utilized to control changes within the hysteresis band. The second control regime can use open-loop based adjustments to the component.

Abstract: When there exists an error between a model considered in feed-forward and an actual device, it is configured so as to enable the application of control having feed-forward such as predictive control without problem to reduce a model error. Furthermore, it is configured to enable more fine adjustment of the actual device by adjusting the balance of gains ? and ?. An operational unit is provided with an error signal calculation unit for outputting an error command and an error feedback value based on a position feed-forward signal and a position detection value, and an error compensation operation unit for controlling so that the error command and the error feedback value coincides with each other. This operational unit is provided at a control operation device.

Abstract: A driver for an electric actuator comprises a direction-switching means which switches a direction of rotation of a rotary driving source based on a direction instruction input signal, a current amplifier/limiter which converts a voltage outputted from the direction-switching means into a corresponding current and which limits the current with reference to a preset reference current IMAX or a threshold value, a current sensor which detects the current supplied to the rotary driving source, and a current loop by which a detection signal from the current sensor is fed back to an upstream side of the current amplifier/limiter.

Abstract: A motor controller provides pulse width modulated drive signals to a motor. A digital demand code for controlling motor speed is input to the motor controller. A dither generator generates a digital dither value, which an adder adds to the demand code to generate a dithered demand code. A position determining circuit determines a rotational position of the motor. A pulse width modulation controller generates pulse width modulated drive signals with duty cycles controlled as a function of a stored set of waveform coefficients, the dithered demand code, and the rotational position of the motor.

Abstract: A method that uses a dither signal for reducing hysteresis effect in a variable cam timing system is provided. The method includes the steps of: a) providing a dither signal having at least two switchable frequencies; b) determining the frequency characteristics of an engine speed; c) determining at least one frequency beating point in relation to a neighborhood of an engine crank RPM values; and d) changing the dither signal frequency when the engine is operating within the neighborhood of the engine crank RPM values. Thereby frequency beating effect is reduced.

Abstract: An equipment for controlling an industrial robot, which robot has a plurality of rotation and/or translation axles (ax 1-6), comprising a motor (15) at each of said axles for generating desired movements of the arms and/or the wrist, of which the robot is constituted, a sensor at each of the axles for measuring axle angle and/or axle position, a servo (9) for each of the axles for controlling the motors based on measurement values from the sensors, and a path generator (8) for generating at least one reference (&phgr;ref, &phgr;ref, &tgr;ffw) for each of the servos (9).

Abstract: A motor control circuit 10 which controls the speed of a motor 12 by the use of pseudo-randomly generated signals 52.

Abstract: A motor control apparatus is arranged to drive and control a motor for transmitting the rotating force of the motor through a gear train. In reversing the rotation of the motor, the motor is caused to rotate at a speed higher than a normal rotation speed for a period of time which is about the same as a period of time required for absorbing a clearance or play existing between the gears. In this instance, since the motor is under no load, the motor is rotated at the higher speed with a small current and a small torque. The arrangement effectively lessens a noise generated in reversing the rotation of the motor due to the clearance or play existing in the motor driving force transmitting part.

Abstract: A method and apparatus for compensating for the effects of compliant elements in a positioning system is provided. The amount of compensation to be applied can be determined by measuring the lost motion errors which are prevalent during continuous motion of the movable member of the system. The compensation value determined can be used to adjust servo control commands, such as position commands for example. Preferably, the compensation is applied when the movable member is in motion and removed when the movable member comes to a stop. Even more preferably, the compensation is applied and removed gradually. The compensation can be used in additional to friction compensation and backlash compensation, and can be implemented in a machine tool system.

Abstract: A noise dithering system provides gating signals to switching transistors that selectively apply power to an output device in response to the gating signals, wherein said gating signals include a selected level of frequency modulation insufficient to alter operational characteristics of the output device more than a predetermined amount. One embodiment concerns a PWM switching system in which a PWM controller provides gating signals to switching transistors, where the gating signals are clocked by a timing circuit in accordance with a modulated input reactance sensed by a timing input node. In another embodiment, the gating signals may be clocked by the timing circuit in accordance with a modulated current at a timing input node, provided by a variable current source. In the case of the modulated input reactance, a voltage variable capacitor is preferably used to provide a capacitance proportional to output of a modulator.

Abstract: Compensation for friction affecting motion of moveable machine members is effected in servo control of the member actuators. An estimate of velocity is used in evaluation of a model of frictional force to produce compensation values. Alternative embodiments provide continuous models of estimated velocity and frictional forces and state models of estimated velocity and frictional forces. Compensation values determined according to either embodiment may be produced for application to servo control commands such as position or torque. The compensation accounts for step changes of friction upon reversal of direction of travel.

Abstract: A method for controlling a servo system (10) having friction, in which the non-linear characteristic (20) of the position controller (12) is defined such that the magnitude of the variable Ns, Vs supplied to the servo system (10) having friction in the case of a control deviation .DELTA.x lying outside a predeterminable target region (21) produces a torque or a force which is adequate to tear the servo system free of the stiction torque or stiction and such that the movement energy of the servo system (10) can be dissipated in the target region (21). The additional use of an integral component, which is preferably a function of the control deviation .DELTA.x, increases the steady state accuracy.

Abstract: A control system for a physical plant has a state output detector for detecting operating conditions of the physical plant. A trajectory production unit produces desired operating conditions of the physical plant, and an error production unit produces error signals based on the detected operating conditions and the desired operating conditions. A control signal generator generates a control signal based on the detected operating conditions, the error signals, a control signal generated a predetermined time period ago, an error dynamics adjustment signal, and a control input signal. The control signal generator includes a control input signal generator and an error dynamics signal generator. The control input signal generator generates the control input signal based on a predetermined control relationship. The error dynamics adjustment signal generator generates the error dynamics adjustment signal and the predetermined time period based on a plurality of predetermined error dynamics relationships.

Abstract: A servo control system (100) for controlling a prime mover (16) to position a load (12) to a commanded position in accordance with the invention includes a position sensor (14) for providing a load position signal representative of a position of the load; a controller for producing a control signal controlling activation of the prime mover to cause the load to be positioned at the commanded position including a first summer (20) for producing a first difference signal equal to a difference between a position command specifying the commanded position and the load position signal which is applied to a proportional amplifier (22) and an integrator (24), a second summer (26) for producing a sum of outputs from the proportional amplifier and the integrator and a third summer (104) for producing the control signal which is equal to a difference between the sum of the outputs and a signal proportional to the load position signal.

Abstract: A dynamic vibration absorber for reducing vibrations of a platform induced by an oscillating mass mounted thereon is provided by mounting a mass of equal mechanical resonant frequency as that of the oscillating mass and oscillating this mass in a manner to establish an equal and opposite vibration of the platform, thereby cancelling the vibrations induced by the oscillating mass. In one embodiment, a signal from the oscillating mass representative of the frequency and amplitude of its mechanical oscillation is phase shifted and utilized as a driving signal to the drive motor of the absorber mass. In another embodiment, electrical signals representative of the platform vibrations are detected to provide phase and amplitude vibration error signals. These error signals are applied to a reference signal coupled to the drive motor of the canceller mass causing the oscillations of the canceller mass to induce vibrations in the platform which counter the vibrations induced by the oscillating mass.

Abstract: A motor drive system used with industrial robots, processing machines, and the like comprising an external interface part ready for connecting a plurality of kinds of host controllers generating a command signal; a sensor interface part to which a motor rotation detecting sensor is connected; a main control part operating for feedback control of a motor according to signals provided by way of the interfaces; and a power amplification part for feeding a current to motor coils according to a control signal from the main control part and wherein the external interface part, the sensor interface part, the main control part, and the power amplification part are separate and modularized as cards. Advantageously, the various controllers, sensors and power systems are changeable to flexibly meet different user requirements.

Abstract: An adaptive control system, for a plant such as a servo motor, a heat pump and the like where its input distribution matrix is known and the number of effective inputs is the same as the number of independent outputs, comprising: an unknown dynamics value production circuit for producing an unknown dynamics value by adding a derivative value of a detected state output value of said plant, negative quantity of multiplication of an input value of said plant and an input distribution matrix value of said plant, and negative quantity of a known value of said plant; a non-identity filter, except for a time delay element, for producing a filtered unknown dynamics value which is close to but not exactly the same as said unknown dynamics value; a control input value production circuit for producing a control input value to said plant by using said filtered unknown dynamics value.

Abstract: This invention relates to a method of creating NC data for rough machining, in which a cutting path (QLi) for rough machining is outputted using points on an i-th point sequence path (PLi) from among a plurality of point sequence paths repeatedly digitized at a predetermined interval in a predetermined direction. The next cutting path for rough machining is created and output using a projected point sequence path (PLk') which, among those projected point sequence paths spaced away from the i-th point sequence path by a distance greater than a tool radius (Tr), is that nearest an i-th projected point sequence path (PLi').

Abstract: A servo loop control for the dither drive of a Coriolis rate sensor is provided. The dither drive includes a pair of electromagnetic coils (70), which are alternately energized to dither a parallelogram frame (50), on which first and second accelerometers (20 and 22) are mounted with their sensitive axes antiparallel to each other. An LVDT position sensor (106) provides a feedback signal indicating the relative position of the two accelerometers or displacement of the parallelogram frame as it is dithered back and forth. The position signal is summed with a driving signal, amplified and summed with a velocity aiding signal and a velocity signal derived by differentiating the position signal. The resulting sum is amplified and again summed with an acceleration aiding input that includes compensation for a phase shift in the motion of the parallelogram frame relative to the driving force applied by the electromagnet coils, and for (I.sup.2 and 1/D.sup.

Abstract: Movement of a tool relative to a workpiece along each one of a plurality of axes is controlled by digitally providing a train of digital pulses to an electromechanical actuator and by digitally modulating the pulse widths (without an intervening conversion to analog form) so that electrical energy is carried in the pulse train at rates which will cause the actuator to tend to produce an intended sequence of speeds and positions.

Abstract: For use with overhead axes of a machine tool or the axes which ride astride one another of a robot, the gravitational effect can be eliminated for controlled drives if a control variable which opposes the gravitational effect is inserted into the control loop of the controller. By this arrangement, a wide control range can be achieved for the overall machine tool or system.

Abstract: A control system and method including an integrator coupled with a rate-varying multiplier which operate in parallel with a conventional controller. Because the integration is rate-variable, the resulting control system has the benefits of an integral position control without the problems of integral windup and subsequent overshoot. The system and method have less following and steady state error, faster settling time and better tolerance to noise than traditional PD and PID controls in controlling dynamic manipulators such as robots. Also, because the integrations are performed in a rate-variable manner, errors due to mechanical static friction, i.e. "sticktion", are substantially reduced without sacrificing dynamic performance of the system.

Abstract: The gain of a servomotor driven process control system is adaptively compensated for changes in the motor coulomb friction torque. The gain is manually adjusted at the time of installation. Thereafter, the minimum motor current occurring in a process cycle is identified, and the gain is automatically adjusted if the identified minimum motor current changes over time, indicating a change in the motor coulomb friction torque. As a result, the level of response stability achieved at the time of installation is maintained despite changes in the motor coulomb friction torque.

Abstract: A dither motor system is described for a ring laser angular rate sensor which forms part of a spring-mass system. The dither motor system of the present invention provides selected control of the peak clockwise and/or peak counterclockwise dither angle of rotation of a spring-mass system.

Abstract: The invention relates to a method and a device for increasing the linearity of a servo system, for instance a gun servo. The servo system comprises an oscillator (6) having a fixed frequency for superimposing a so-called dither signal on the control signal of the servo system. The frequency of the dither signal is so chosen below, about or just above the upper frequency limit of the servo system. The linear effect produced by the dither signal results in a higher gain attained in the system even for very small signals.

Abstract: A signal generating means including a half-round magnet attached to the spindle of a machine tool and mounted relative to a first reference indicator and a pair of opposingly mounted magnetic switches magnetically coupled to the magnet and mounted to a stationary portion of the machine tool and aligned relative to a second reference indicator for generating a first signal when the first magnetic switch is activated by the magnet, a second signal when the second magnetic switch is activated by the magnet; gating means, responsive to the first and second signals for generating an orient signal to orient the spindle to a reference position and a controller means for supplying to the spindle driving signals during the normal mode of operation and for supplying to the spindle during the orientation mode orient signals to cause the spindle to become aligned to the reference position.

Abstract: An electrical actuator such as a direct current solenoid or motor is energized by a square wave voltage having an amplitude which applies full operating voltage to the actuator during each pulse. The duty cycle of the applied voltage is variable between predetermined minimum and maximum values, the minimum value being sufficiently high to overcome the starting hysteresis of the actuator. The control apparatus has particular application to proportional control systems, such as in the selective operation of dual solenoid, hydraulic control valves. A hand controller is provided with a handle having a center off position and on positions in opposite directions corresponding to the two solenoids. As the handle is moved away from the off position in either direction through an initial, relatively small displacement, a switch is actuated to apply the square wave voltage to the appropriate solenoid. Additional movement by the operator causes the duty cycle to vary from minimum to maximum as desired.

Abstract: A servo system has a moving member supported for movement therein and a pickoff device for sensing the position of the moving member relative to a reference position. The pickoff provides a position output which is connected to an attenuator at the input of a high gain amplifier having a feedback loop for attaining gain stability. The feedback loop contains circuit components which provide stability in the servo system. An amplifier output attenuator reduces the feedback loop signal levels. Amplifier output is coupled to motive means for driving the moving member toward the reference position. A timing circuit produces a timed output which dissipates over a predetermined period of time. The timed output operates to enable a field effect transistor which causes the input divider to attentuate the position output to the high gain amplifier.

Abstract: A circuit for providing an oscillatory driving signal from the point in time when power is supplied to a predetermined point in time thereafter. A force balance transducer having a pick-off device with a stationary member and a moving member mechanically mounted for movement relative to the stationary member is disposed to sense a predetermined physical quantity and to produce an output relative thereto. A force producing device is coupled to the moving member for receiving the output and for driving the moving member to a predetermined neutral position. The transducer is actuated by a source of electrical power and contains a gating circuit, an astable multi-vibrator and a coupling circuit. The gating circuit is actuated by initial application of the electrical power to the transducer and actuates the astable multivibrator for a predetermined period of time.

Abstract: A four-quadrant full-wave static converter having improved time response without current cross-over deadband. An alternating current wave is imposed on the direct current input signal, which generates gate pulses for appropriate thyristors at the desired firing angle. The applied alternating current signal can be of approximately the same magnitude as the converter deadband, so as the direct current signal varies from zero a portion of the control signal moves out of the deadband area. For fast response the magnitude of the alternating current signal can be greater than the deadband signal. As the magnitude of the direct current signal increases the relative magnitude of the alternating current signal is decreased, preventing a large DC component from being imposed on the supply during high current operations. Cycling of the imposed alternating current waves is synchronized with the firing angle point O to maintain system protection.

Abstract: A multi-range, self-balancing instrument using a Zener diode circuit and a phase compensating circuit is disclosed. The Zener diode circuit is capable of generating a white noise, which is effectively applied to the self-balancing system whereby the dead zone is maintained constant irrespective of the range. The phase compensating circuit, comprising a non-inverting input amplifier, is capable of compensating for the phase lag of the self-balancing instrument by adjusting the amplification factor of the amplifier without affecting the stability of the servo amplifier system.