Abstract: A flow control device for use in a heat exchange system, including: a housing, a movable valve member and a drive control member, the housing being formed to have a mounting cavity, a first interface and a second interface, while the drive control member includes a control unit, a power output unit, a magnetic element and a detection element; the power output unit provides power to the movable valve member, while the detection element and the control unit are electrically connected, and the magnetic element and the power output unit are mutually assembled and oppositely fixed, the power output unit may drive the magnetic element to rotate; the detection element and the magnetic element are oppositely disposed, the detection element being located within the range of the magnetic field of the magnetic element, the detection element may sense a magnetic pole change of the magnetic element.

Abstract: A controller coupled to a motion actuator responsively varies a speed of the motion actuator and an operating speed of a working surface within the range of an initial speed and a max speed and responds to a derived force that represents an amount of force an operator applies between a workpiece and the working surface. The controller, under both acceleration and deceleration, allows the operator with an applied force to manageably change simultaneously both a rate of work on the workpiece and the operating speed of the working surface according to a sensitivity profile expressing a relationship between the derived amount of force and the operating speed of the working surface. A tool for operating on the workpiece includes the motion actuator coupled to the working surface to engage the workpiece.

Abstract: The present invention provides a vibration control apparatus which controls vibration of an object supported via a support having a damping coefficient, the apparatus comprising a driving device configured to drive the object, and a controller configured to perform negative feedback control of the driving device based on information of vibration of the object, wherein the controller is configured to perform positive feedback control of the driving device based on information of a velocity of the object so as to reduce a force which the support causes to act on the object in accordance with the velocity.

Abstract: A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The head is used to read data recorded on the disk to generate a read signal, and the read signal is processed to generate a current command signal at a servo sample rate having a servo sample interval. A current flowing through the VCM is detected, and a current error signal is generated based on a difference between the current command signal and the detected current flowing through the VCM. An analog command signal is generated based on the current error signal, and the analog command signal is applied to the VCM. A saturation in the analog command signal is detected, and a first deglitch window is generated during which the saturation detection is disabled, wherein the first deglitch window is programmed relative to the servo sample interval.

Abstract: A numerical control device wherein a sinusoidal signal generated by a sine wave generation part is input by a control loop excitation part to a control loop of the control object, the input signal input to the control loop and the output signal from the control object are sampled by the data acquisition part periodically, and the sampling data is used by the frequency characteristic calculation part to calculate the frequency characteristic of the control loop to control the control object, wherein the frequency characteristic calculation part uses data obtained by inputting a sinusoidal signal obtained by shifting an initial phase of the sinusoidal signal by a phase shift part provided at a sine wave generation part by exactly a certain amount to the control loop a plurality of times to calculate the frequency characteristic of the control loop to thereby improve the measurement precision regardless of the sampling frequency.

Abstract: A stage system includes a stage that holds an object, a linear motor mechanism that moves the stage by a thrust force generated by a current flowing through the coil, and a control section that controls the current flowing through the coil. The current flowing through the coil in a state where the stage is maintained in the static state be greater than a minimum current amount required for generating the thrust force greater than a maximum static friction force of the stage with respect to the guide rails.

Abstract: Variable autonomy level control systems are provided. A control system illustratively include an analog communications support component, a digital communications support component, a processing component, and a motor controller. The processing component synthesizes inputs received from the analog and the digital communications support components to generate an output. The motor controller utilizes the output from the processing component to generate a control signal for a motor. In certain embodiments, the input from the digital communications support component includes an indication of an autonomy level, and the processing component synthesizes the inputs by applying the autonomy level to the input received from the analog communications support component.

Abstract: A valve actuator including an electric motor is disclosed that includes a solid-state motor controller capable of operating a motor at variable speeds and a gear set that provides inherent braking. The speed and torque of the valve actuator may be selected. The speed and torque experienced by a valve may be varied over the length of a valve stroke. The valve actuator may include logic sufficient to act as a process controller.

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: In order to obtain an NC device that can easily shift by an arbitrary amount a main spindle single-revolution reference signal without being dependant on hardware and while rotating a main spindle, the NC device includes a main spindle reference angle correction amount setting unit for inputting a correction angle of a reference point, a main spindle within-single-revolution feed-back position correction unit for correcting the reference point by a correction angle set by the main spindle reference angle correction amount setting unit, and a main spindle within-single-revolution command position correction unit for correcting a main spindle within-single-revolution command position by the correction angle set by the main spindle reference angle correction amount setting unit.

Abstract: The present invention provides a stage apparatus capable of reducing a positioning time without increasing a positional deviation. A positioning control method of a sample stage apparatus includes: a high-speed movement step of moving a table to a high-speed movement target position at a first movement speed; a positional deviation correcting step of moving the table to a low-speed positioning step start position at a second movement speed that is lower than the first movement speed; a low-speed positioning step of moving the table to a target position at a third movement speed that is lower than the second movement speed. After the low-speed positioning step is completed, a rod connected to a motor returns to its original position to separate a pin of the rod side from a concave portion of the table side.

Abstract: When generating an origin signal of an encoder having a scale on which an incremental pattern and the origin pattern are formed, an origin signal having a necessary position and width is generated by software based on an origin waveform obtained from the origin pattern. This enables origin detection with excellent repeatability, S/N ratio (pulse width), and bidirectionality while maintaining ease of mounting and adjustment.

Abstract: A controller receives an M-bit input and generates, in response, an S-bit upper range binary data feeding S-bit high range DAC and an R-bit lower range data feeding an R-bit low range DAC. The controller detects transition points in the M-bit input and in response, adds a transition data to the S-bit data equal to at least one least significant bit of the S-bit data and subtracts a value from the R-bit data equal to the transition data. The transition points and the transition data are detected and added at points avoiding such transitions at a full scale value of the R-bit data.

Abstract: Methods and systems for detecting an angular position of an electric motor are disclosed, including sending an electrical pulse through a stator coil of the electric motor, determining an approximate angular position of a rotor of the electric motor in response to detecting an timing of a returning electrical pulse from the stator coil, the timing of the returning electrical pulse being indicative of the angular position of the rotor; and determining an accurate position of the rotor in response to sensing a transition of a digital sensor in response to the rotor rotating relative to the stator, the transition being indicative of the accurate position.

Abstract: The invention relates to a method for materials handling via a number of materials handling cells by passing on materials handling containers, in which each materials handling cell includes a first electric motor and a first control unit, in which each materials handling container is assigned at least one data element including at least information about the way or the destination of the materials handling container, in which the data element is passed on to the next materials handling cell and stored there in the control unit, when the materials handling container is passed on there, and where the evaluation of the data element and the control of its passing on is performed in the first control unit contained in the first electric motor, as well as to a materials handling cell and to an electric motor therefor.

Abstract: The present invention provides a stage apparatus capable of reducing a positioning time without increasing a positional deviation. A positioning control method of a sample stage apparatus includes: a high-speed movement step of moving a table to a high-speed movement target position at a first movement speed; a positional deviation correcting step of moving the table to a low-speed positioning step start position at a second movement speed that is lower than the first movement speed; a low-speed positioning step of moving the table to a target position at a third movement speed that is lower than the second movement speed. After the low-speed positioning step is completed, a rod connected to a motor returns to its original position to separate a pin of the rod side from a concave portion of the table side.

Abstract: A relatively small, lightweight actuator includes a plurality of motors, an actuation element, a translation member, and a plurality of position sensors. The motors each supply a drive force to the actuation member, causing it to rotate. The translation member is configured, upon rotation of the actuator, to translate to a position. The position sensors sense the translational position of the translation member and the rotational position of each motor. The actuator is relatively small, lightweight, and can withstand the relatively severe environmental conditions and relatively significant levels of vibration and shock associated with many aerospace applications.

Abstract: A fan power supply system having a pair of voltage supplies, one producing a higher voltage than the other. A switch selects one of the voltage supplies in response to a control signal. A DC/DC converter is connected to the selected one of the voltage supplies for producing a current greater than current fed to the DC/DC converter by the selected one of the voltage supplies. A fan is fed by the current produced by the DC/DC converter. The fan produces a train of pulses representative of the rotational speed of the fan. A microcontroller encodes the train of pulses produced by the fan as a function of whether the selected one of the pair of voltages has the higher voltage or the lower voltage. A decoder produces the control signal in accordance with the encoding by the microcontroller.

Abstract: A fixed-position stop control apparatus (10) includes: a move-instruction generating means (22) for generating a move instruction for each control cycle; a position loop control means (25) for position controlling a rotation shaft (61) for each control cycle according to the move instruction generated by the move-instruction generating means; and a speed loop control means (35) for speed controlling the rotation shaft according to one of a speed instruction generated by a higher level control apparatus (45) and a predetermined speed instruction, thereby switching the speed control of the rotation shaft by the speed loop control means to the position control of the rotation shaft by the position loop control means. In this fixed-position stop control apparatus, the move instruction generated by the move-instruction generating means has acceleration smaller than the acceleration corresponding to the acceleration and deceleration ability of the rotation shaft.

Abstract: A device controller system incorporates an inexpensive Hall element to detect motion of a brushless DC motor. A magnet, which is part of a motor rotor, passes by the Hall element producing a Hall voltage each rotation. The Hall voltage is coupled through an interface port to a comparator within a process controller. A microprocessor within the process controller calculates a control response based on a comparator output signal. The interface port is rapidly reconfigured to provide signals produced from the control response as output to device drivers on the same input-output pins that receive the Hall voltage. The device drivers produce a current through fan coils producing an update in the magnetic field of each motor phase which updates the speed of the fan according to programming within the process controller. Rapid configuring and reconfiguring of the interface port allows all necessary components of the controller system to be used with a single rotational commutation cycle.

Abstract: A method is for detecting a possible collision of at least two objects moving with respect to each other by simulating the intended relative motion of the two objects. At least one of the objects is assigned an envelope surrounding the object, the path line represents the relative motion of the objects is covered in steps of a defined step size, and the occurrence of an overlap of the objects is detected for ascertaining a possible collision of the objects. For at least one object, the outer contour of the corresponding envelope is used as a datum for detecting an overlap. At least one object is assigned an inner and an outer envelope, of which the inner envelope surrounds the object and the outer envelope surrounds the inner envelope. The outer envelope is used as a datum for detecting an overlap of the two objects, and when an overlap is detected in a segment of the path line, the segment of the path line is re-traversed using a smaller, second step size.

Abstract: In a press having a plunger supported so as to be movable linearly back and forth by drive means which include at least one servomotor in combination with a rotatably supported inertia structure connected for rotation with the servomotor, the inertia structure has an inertia moment which is small enough to permit reversal of the servomotor within a stroke length of the plunger so that the stroke of the plunger is adjustable under the control of a control device connected to the servomotor for controlling its operation.

Abstract: An actuating system having an electric motor that is controlled by a computer as a function of a setpoint position of a member that is to be actuated. The actuating system includes an encoder that is dependent on the movement of the motor, a sensor designed to deliver two square digital position signals in quadrature and which are representative of the position of the encoder, a device for processing the signals and which can determine the actual position of the encoder, and a device for comparing the actual position of the encoder with the position of the encoder that corresponds, in theory, to the applied setpoint. The actuating system can be used to actuate a member and/or actuate a device that meters the amount of fuel provided to a heat engine.

Abstract: In a servomotor controller, when a comparing circuit (70) detects that a position of an object to be controlled has been achieved to a target position, an operation inhibiting signal generating section (71) supplies an operation inhibiting signal (71a) to an operation permitting/inhibiting signal-processing section (66), and obtains an operation stopped state of an H bridge-driving processing section (67) for controlling driving of a motor. A LIN communication processing section (61) receives information to a self address supplied from a superordiante device, and outputs a forced operation (recovery) request (61R) in the received information. The operation state of the H bridge-driving processing section (67) is obtained through an operation permitting trigger signal generating section (65) and the operation permitting/inhibiting signal-processing section (66) through the H bridge-driving processing section (67).

Abstract: A serially connected double-phase full-wave brushless dc motor includes a first drive member, a second drive member, a first sensor member, a second sensor member, a first motor coil and a second motor coil. The first drive member is connected to a power source to thereby obtain a first voltage, and connected to the first sensor member and the first motor coil. The first drive member is further in serial connection with a second drive member and a second sensor member, and provides with a second voltage thereto. The second drive member is connected to the second sensor member and the second motor coil. Hall signals of the first and second sensor members are in control of an alternative direction of the first and second motor coils for conduction, and thereby the first and second motor coils are synchronously excited in full wave by the first and second voltages respectively.

Abstract: The invention provides a synchronous motor sensorless controller which drives a synchronous motor without use of a rotational position sensor. The controller has a relative position counter 4 which acquires an estimated position of a magnetic pole from the position-and-speed estimation device simultaneously with resetting a summated value to zero when the reference position signal is input and which starts summation operation; and a speed instruction generator 3 having a position controller 29 which performs position control operation on the basis of a deviation between an instruction value pertaining to the amount of movement from the reference position and a summated value output as a relative position from the relative position counter, the generator outputting a speed instruction. The sensorless controller can position at a predetermined location a synchronous motor not having a position sensor.

Abstract: The invention reduces the oscillation of the rotation speed regulator when stationary—despite low position resolution and a high minimum rotation speed resulting from this—by switching the closed-loop control structure, when the drive is moved into the nominal position, in which case the closed-loop control structure does not need to include a current regulator when stationary. The control voltage is predetermined directly by the rotation speed regulator (2′), which is in the form of a pure P-regulator. If the rotor is deflected, then dynamic negative feedback is carried out by differentiation (9) of the position (&phgr;). The position control loop (1′), which is at a higher level than the rotation speed control loop (2′), is in the form of a PI regulator in order that no permanent position errors can occur.

Abstract: A motor-driven power steering apparatus includes a motor for generating assisting force to be imparted to a steering mechanism, a control signal generation section for generating a motor control signal on the basis of at least steering torque applied to a steering wheel, a motor drive unit for driving the motor in accordance with the motor control signal, and a step-up circuit provided between a battery to the motor drive unit. The step-up circuit includes a step-up coil whose one end is connected to the battery, a first switching element connected between the other end of the step-up coil and the ground, a second switching element connected between the other end of the step-up coil and an output terminal, and a capacitor connected between the output terminal and the ground and smoothing output voltage appearing at the output terminal.

Abstract: Method and apparatus for controlling a motor. A digital to analog converter (DAC) converts input digital values to corresponding analog voltages over a range of different selectable dynamic operating ranges. A first motor adjustment signal within a first dynamic range of the DAC is generated in relation to a velocity error of the motor, and applied to the DAC to control flow of current through the motor. The DAC is adjusted to a different, second dynamic range when the first motor adjustment signal is proximate an upper end or a lower end of the first dynamic range. Expanding the dynamic range allows greater amounts of current to be applied to the motor; contracting the dynamic range provides higher resolution (volts/count) and greater stability. The different ranges are automatically selected for different motor load conditions.

Abstract: Aspects of a current controlled motor amplifier system are provided. These aspects include a current source motor amplifier comprising current source means on each leg of a top half of the H bridge configuration and switching means on each leg of a bottom half of the H bridge configuration. A motor is coupled to the current source motor amplifier at a center portion of the H bridge configuration. Control circuitry is coupled to the current source motor amplifier for controlling the switching on of the current source motor amplifier for a predetermined time to operate the top half of the H bridge configuration essentially as a linear constant current source and the bottom half of the H bridge configuration in switching mode. The aspects also allow for simplified circuitry to protect against overvoltage conditions and eliminate electrical damping in applications with higher rotational velocities associated with induced back EMF.

Abstract: The invention makes it possible to execute the pre-control and the fine interpolation in the drive (A) in the fast drive clock (tDR) with a slower path pre-setting in the clock (tNC) of the NC. For this purpose, in each NC clock (tNC) a setpoint speed value (nNC*) and the P gain (kP) of the NC position controller (L_NC) and the desired axle speed (nNC) and the average axle speed (nNCMW) during the last NC position controller clock are transferred from the NC to the drive. From this information, polynomial segments of the third degree are in each case generated on the drive side, valid for the duration of an NC position controller clock (tNC). They are constructed in such a way that the speed at the polynomial transitions is constant. A variable component of the position polynomial is determined as the fine position component xF, with which the setpoint position values are finely interpolated in the drive.

Abstract: The invention makes it possible to execute the pre-control and the fine interpolation in the drive (A) in the fast drive clock (tDR) with a slower path pre-setting in the clock (tNC) of the NC. For this purpose, in each NC clock (tNC) a setpoint speed value (nNC*) and the P gain (kP) of the NC position controller (L_NC) and the desired axle speed (nNC) and the average axle speed (nNCMW) during the last NC position controller clock are transferred from the NC to the drive. From this information, polynomial segments of the third degree are in each case generated on the drive side, valid for the duration of an NC position controller clock (tNC). They are constructed in such a way that the speed at the polynomial transitions is constant. A variable component of the position polynomial is determined as the fine position component xF, with which the setpoint position values are finely interpolated in the drive.

Abstract: An apparatus for setting control parameters of a machining apparatus. The setting apparatus includes a storage unit for storing a set of control parameters for each of a plurality of machining modes; an input device for selecting one of the plurality of machining modes; and a control unit for selecting a set of control parameters corresponding the selected machining mode and setting the set of control parameters as control parameters to be used for controlling the machining apparatus.

Abstract: The invention relates to a method and an apparatus for defining the position of an actuator. The position of the actuator (1) is measured by a measuring signal (3) proportional to the rotation of a shaft (6) of the actuator (1). The measuring signal (3) comprises successive pulses. The intervals between the pulses are divided into parts, and the position of the actuator (1) between the pulses is defined utilizing the parts of the divided pulse intervals.

Abstract: Disclosed is a method in a disk drive that allows the functionality of a single high-resolution DAC to be replicated with a pair of lower-resolution DACs that are operated in a unique manner that provides monotonic behavior and reduces both differential and integral non-linearity. The two lower-resolution DACs take up substantially less space that one higher-resolution DAC when implemented in a semiconductor die. The method combines coarse values from one DAC with fine values from the other DAC to form a combined analog output signal within operational segments that collectively span a range of N-bit demands. The method operates such the operational segments overlap one another by 50 percent, with an endpoint of each operational segment ending near a center of an overlapped operational segment.

Abstract: The invention relates to a method for positioning an actuator. In the method, the actuator is controlled by a continuous control pulse (2a) toward a desired value (1), and the position of the actuator is measured. Further, a pulsing range limit located before the desired value (1) is defined, and when the position of the actuator is past the pulsing range limit (3), the motion of the actuator is stopped. The pulsing range limit (3) is defined to be so far from the desired value (1) that the actuator stops before its position is substantially past the desired value (1). The position of the actuator is then measured, and if necessary, a corrective run is performed.

Abstract: A brushless direct current motor driving circuit includes a data generator adapted to receive a first signal corresponding to a rotor position and to generate a digital data signal therefrom, a clock signal generator adapted to receive phase voltage signals and back electromotive force (BEMF) signals from a motor and to generate a clocking signal therefrom, and a data output block coupled to the data generator and the clock signal generator and adapted to receive the data signal and the clocking signal such that the digital data is clocked into the data output block as a result of the BEMF signals to produce a frequency signal to be used in controlling the velocity of the rotor. Switching noise present together with the BEMF signals is rejected by the clock signal generator so that the frequency signal is substantially free from switching noise, thereby allowing a velocity controller to provide more precise velocity control of the rotor.

Abstract: An improved stop control system and method are provided for a motor having a drive mechanism in which the motor is coupled to a motor controller that controls the speed and position of the drive mechanism using a first signal indicative of a commanded position of the drive mechanism, a second signal indicative of the actual speed of the drive mechanism and a third signal indicative of the actual position of the drive mechanism. The improved system/method uses a first circuit that receives the first and third signal and generates an error signal indicative of a difference therebetween. A second circuit receives the error signal and compares same with a threshold position error. The result of this comparison is used to selectively supply the second signal (i.e., speed) to the motor controller at least whenever the error signal is less than the threshold position error so that the motor controller can use the second signal in conjunction with the third signal to stop the motor.

Abstract: A machine tool assembly having a rotatable element for driving a tool to operate on a workpiece and structure for driving the rotatable element in rotation. The driving structure has a first power source and first structure cooperating between the first power source and the rotatable tool driving element for selectively a) allowing the first power source to be operated at one speed to drive the rotatable tool driving element at a first operating speed with the machine tool assembly in a first state and b) allowing the power source to be operated at the one speed without rotating the rotatable tool driving element at the first operating speed with the machine tool assembly in a second state. Structure is provided for changing the machine tool assembly from one of its first and second states to the other of its first and second states.

Abstract: A signal processing apparatus is provided for processing first and second periodic analog signals having the same period and having a fixed phase relationship therebetween. The apparatus includes an A/D converter for converting respective amplitudes of the first and second periodic analog signals into first and second digital signals. The apparatus also includes a phase digitizer for generating a signal from the first periodic analog signal, the generated signal having a period that is shorter than the period of the first periodic analog signal, and a high speed signal processing portion for generating from the generated signal a periodicity and first phase information of the first periodic analog signal. The apparatus further includes a another signal processor for producing second phase information of the first periodic analog signal from the first and second digital signals, and for correcting the periodicity on the basis of the first phase information and the second phase information.

Abstract: A numerical control apparatus allows a portion of a prototype or the like to be easily machined without an operator being concerned with a coordinate system, origins, and other data. A guidance function executing unit displays guidance information on a display unit. According to the displayed guidance information, the operator enters machining commands using a keyboard, etc. A pulse distributing unit sends present positions from present position registers to the guidance function executing unit. The guidance function executing unit calculates a movement command from command values commanded by the operator and the present positions, and sends the calculated movement command to the pulse distributing unit, which outputs distributed pulses to drive the machine tool.

Abstract: A hybrid servomechanism includes a speed control, a rotor position control and a brushless motor. When enabled, the position control commands a stationary stator mmf vector, allowing the motor's rotor to rotate until load torque and motor torque are balanced. This position control eliminates limit cycle operation and allows the motor to compensate for backdriving caused by external loads.

Abstract: A method and circuit for implementing a frequency lock loop circuit in a disk drive is disclosed. The circuit includes the motor control elements of a direct current motor plus a coarse counter, a fine counter, and a digital to analog converter. The coarse counter is used to count down from a programmed coarse count. The fine counter begins to count down from a fine count when the coarse counter reaches zero. The count in the fine counter, when a zero crossing occurs, represents the difference between the expected period and the actual period and is loaded into a digital to analog converter which converts the difference to an analog voltage which is used by the coil drive circuit to either speed up or slow down the motor. The digital to analog conversion may be realized by a charge pump circuit.

Abstract: A spindle positioning method for high-speed positioning of a spindle by making the best use of the decelerating capability of a spindle motor. When a fixed-position stop command is generated while the operation of the spindle motor is controlled according to speed control, the motor rotation speed is reduced in accordance with the speed control to a speed N lower than or equal to a maximum rotational speed N1, which defines a constant torque region, and a control mode is switched from the speed control mode to position control mode at a point where the rotational speed is reduced to the speed N. Simultaneously, a value specifying the relation between the present position and target stop position of the motor with respect to one revolution of the spindle is set in an error counter as an initial position deviation.

Abstract: An actuator'rate is controlled by a rate servo and the actuator's position is controlled by a position control. The position control can be a position servo or a mechanical brake. Selection of either the rate servo or position control is made by fuzzy switching logic.

Abstract: The invention relates to a spindle speed/position control system for use in a numerically controlled machine tool such as a lathe. To improve the measurement of spindle speed and position, detected elements are attached directly to the rotatable spindle. A waveform shaping circuit takes the outputs of speed and position detecting sensors, and outputs a variety of sinusoidal and pulse signals. The sinusoidally varying signals are employed in speed detection while the pulse signals are used for position detection and control.

Abstract: A process for controlling a robot arm having a certain number of articulations or joints (A to F), which can abut. Substitution paths are automatically defined by calculation or by the choice of intermediate objectives in order to arrive at destination points, when the direct path would involve the abutment of certain joints.

Abstract: A servo circuit for a magnetic disk apparatus includes a target speed generating circuit which generates a target speed in accordance with an amount of movement. A speed signal producing circuit produces a real speed from a position signal from a servo object. A speed error generating circuit controls the speed of the servo object based on an error between the target speed and the real speed. Acceleration and deceleration control are performed to position the servo object at the target position. An acceleration detection circuit detects acceleration and outputs an acceleration-in-progress detection signal for changing a cut-off frequency of the speed error generating circuit between acceleration and deceleration. The servo circuit has a servo loop which supplies a seek current based on an error signal between a target speed and real speed to a voice coil motor and performs speed control on a head carriage.

Abstract: A servo circuit having a speed detection circuit for detecting a real speed from a position signal from an object under servo control. A speed error detection circuit generates an error between a target speed and the real speed. A position error detection circuit generates a position error signal from the position signal. A switching unit switches connection of the servo object to the speed error detection circuit and the position error detection circuit. A main processing unit controls the switching of the switching unit. Near the target position, speed control by the speed error detection circuit is switched to position control by the position error detection circuit. A speed detection gain adjustment unit is provided in the speed detection circuit. The main processing unit measures the intervals between the position signals and, based on the measured value, changes the detection gain of the speed detection gain adjustment unit.

Abstract: A control system for a servo circuit has a speed control unit for controlling the speed of a servo object, a position control unit for controlling the position of the servo object, a switching unit for switching between the speed control unit and the position control unit, a main control unit, and optionally a speed zero detection circuit which compares the real speed and a slice level and detects if the real speed is less than a fixed value. The control system includes a method for producing a target speed using an amount of movement X in an amount of movement d as a remaining amount of movement, and producing a target speed of equal speed for a remaining amount of movement Y.