Kabushiki Kaisha Sg

Other

Amiteq Co., Ltd.

Eaton Corporation

Atsutoshi Goto

Yasuhiro Yuasa

Hiroshi Sakamoto

Kazuya Sakamoto

Shuichi Tanaka

Nobuyuki Akatsu

Akio Yamamoto

Daisuke Goto

Wataru Shimizu

Shinichiro Uehara

Akira Yamashita

Minoru Ito

Masakuni Tanaka

Shigeru Muraoka

Shuiti Tanaka

Yuuji Matsuki

Hiroshi Sakamato

A coil section includes a primary coil which is magnetically excitable by an AC signal, and secondary coils which are provided so as to generate an inductive output in response to excitation of the primary coil. A self-oscillation circuit, including an inductance element and a capacitor, has incorporated therein the primary coil as the inductance element for self-oscillation. A target section is provided in such a manner that its relative position to the coil section varies according to a position of a target of detection, and the target section includes a magnetically responsive member disposed so that inductance of the secondary coils is varied according to the relative position. Amplitude levels of the output signals of the secondary coils are extracted, and position data of the position of the target of detection is obtained on the basis of these amplitude levels.

Inductive position detection device

A detection coil incorporated in a self-oscillation circuit, which includes the coil and a capacitor and is set to a high frequency band (e.g., around 1 MHz or higher). A target section has a relative position to the coil section that varies in response to displacement of a detection object and includes a magnetism-responsive member constructed to cause inductance of the coil to vary with the relative position. A rectifier circuit extracts an amplitude level of an oscillation output signal of the self-oscillation circuit and outputs the extracted level as detected position data. For example, a plurality of self-oscillation circuits are provided. Alternatively, a single self-oscillation circuit forms a plurality of series circuits by, for each coil pair, connecting in series the two coils of the coil pair, and connecting the series circuits in parallel as an inductor element for self-oscillation.

Position detection device

An excitation AC signal biased by a predetermined DC voltage is applied to a coil to allow a DC voltage component in a coil output signal to contain failure information about disconnection, partial disconnection, or the like of the coil. The DC voltage component contained in the coil output signal is detected, and the detected DC voltage is provided as an offset voltage for a failure diagnosis. Further, to check a peak level of the excitation AC voltage, a DC voltage corresponding to the peak level may be contained in the offset voltage. A differential amplifier circuit for obtaining a difference between a coil detection output AC voltage component and a reference AC voltage component outputs an obtained differential signal offset by the offset voltage. Accordingly, the differential signal containing the offset voltage as the failure information is transmitted to a circuit for torque measurement as a torque detection signal via a single output line. The circuit for torque measurement provides the torque detection data based on the transmitted differential signal and at the same time extracts the offset voltage to use it for the failure diagnosis.

Torque sensor

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(&#x3c9;t&#xb1;d+&#x3b8;), sin((&#x3c9;t&#xb1;d&#x2212;&#x3b8;)) are electrically synthesized which have electric phase angles (&#x3b8;) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. '&#xb1;d' here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (&#xb1;d) appear in the same direction, while the phase differences (&#x3b8;) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (&#xb1;d+&#x3b8;, &#xb1;d&#x2212;&#x3b8;) and performing appropriate operation, it is allowed to cancel out or extract the error (&#xb1;d) so that an accurate phase difference (&#x3b8;) can be detected. Position detection data indicative of the detected phase difference (&#x3b8;) is converted into a pulse-width-modulated signal and transmitted in the pulse-width-modulated form.

Phase difference detection device and method for a position detector

In a control unit for use with a power steering apparatus, there are provided and integrated into a single body, a main operating fluid feed device for supplying the hydraulic cylinder with an amount of oil corresponding to the amount of rotation of the steering wheel H, an auxiliary operating fluid feed device for supplying a correcting oil for adjusting drive of said hydraulic cylinder according to control signal, and a steering wheel angle sensor disposed around the rotating shaft of the steering wheel connected to said main operating fluid feed device, to detect steering wheel angle corresponding to the rotating position of said steering wheel.

Control unit for power steering apparatus and steering-wheel-angle correcting system

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(&ohgr;t&plusmn;d&plus;&thgr;), sin(&ohgr;t&plusmn;d&minus;&thgr;)) are electrically synthesized which have electric phase angles (&thgr;) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. &ldquo;&plusmn;d&rdquo; here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (&plusmn;d) appear in the same direction, while the phase differences (&thgr;) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (&plusmn;d&plus;&thgr;, &plusmn;d&minus;&thgr;) and performing appropriate operation, it is allowed to cancel out or extract the error (&plusmn;d) so that an accurate phase difference (&thgr;) can be detected. Position detection data indicative of the detected phase difference (&thgr;) is converted into a pulse-width-modulated signal and transmitted in the pulse-width-modulated form.

A winding section includes a primary winding to be excited by a single-phase A.C. signal, and a plurality of secondary windings provided at different locations with respect to a predetermined direction of linear movement. A variable magnetic coupling section includes a plurality of magnetic response members provided in repetition at a predetermined pitch along the direction of linear movement, and allows inductive A.C. output signals, amplitude-modulated in accordance with a varying linear position of an object of detection, to be produced in the individual secondary windings with amplitude function characteristics differing depending on positional differences between the secondary windings. Each of the inductive A.C. output signals produced in the secondary windings varies in its amplitude function in periodic cycles each corresponding to the pitch length of the magnetic response members. The variable magnetic coupling section may include a core section made of a wire, and the magnetic response members in the form of metal pieces provided at the predetermined pitch and secured by caulking to the core section.

Induction-type linear position detector device

A group of secondary windings are distributively provided on a stator over a predetermined range, and the respective inductance of the secondary windings in the group is set in such a manner to present predetermined inductance distribution. A rotor has an eccentric shape so as to cause variations in magnetic coupling at individual poles of the stator in response to its current rotational position. By combined use of the magnetic coupling variations between primary and secondary windings on the stator and the predetermined inductance distribution of the secondary windings, high-accuracy detection of a rotational position is achieved with a simple structure. A plurality of primary windings may be set so as to present predetermined inductance distribution.

Induction-type rotational position detecting device

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(.omega.t .+-.d.+-..theta.), sin(.omega.t.+-.d-.theta.)) are electrically synthesized which have electric phase angles (.theta.) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. '.+-.d' here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (.+-.d) appear in the same direction, while the phase differences (.theta.) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (.+-.d.+-..theta., .+-.d-.theta.) and performing appropriate operation, it is allowed to cancel out or extract the error (.+-.d) so that an accurate phase difference (.theta.) can be detected.

Phase difference detection device for an inductive position detector

Drive control units are provided each for one of plural drive shafts for controlling driving of the drive shaft in response to an individually imparted set value. A state parameter generation section generates, for each of the drive shafts, a parameter representing a state concerning a predetermined object of harmonization control among drive control states of the respective shafts produced by the drive control units. As the object of harmonization control, a desired factor may be selected depending upon necessity for the harmonization control. A position loop gain or a velocity loop gain, for example, may be selected as the object of harmonization control. A reference parameter generation section generates, responsive to the generated parameter representing the drive control state of each drive shaft, a reference parameter to be used as a reference of the harmonization control. The drive control state of each drive shaft in each of the drive control unit is corrected in response to the generated reference parameter. In the drive control unit, driving of each shaft is controlled individually in response to a set value which is individually imparted but, by correcting the drive control state in response to the reference parameter, the drive state of each shaft is harmoniously controlled in response to the reference parameter whereby a control for harmonizing the movements of an extremely large number of drive shafts can be realized.

Harmonization control system for plural shafts

There are provided servo motors and servo control units for n shafts. A setting device previously sets parameters for servo control individually for each of the n shafts and previously sets parameters for servo control for a synchronizing operation. Data which determines synchronization conditions of servo motors of respective shafts is applied, when required, by an input device independently of setting by the setting device. The data which determines the synchronization conditions includes, for example, data of combination of synchronized shafts and data of section for synchronization. A moving pattern preparation device determines servo motor shafts to be synchronously controlled on the basis of the synchronization condition determining data applied through the input device and prepares a moving pattern to a target position on the basis of the parameters for servo control set by the setting device with respect to each servo motor shaft to be synchronously controlled. Positioning control data corresponding to the prepared moving pattern is supplied to the servo control unit corresponding to each shaft to synchronously control the servo motor corresponding to each shaft. The synchronization conditions can be changed, when required, by the input device.

Synchronization control system for servo motors

A plurality of speed-sliding compensation amount functions are stored in a sliding compensation amount data memory and one of these functions is selected in response to input of a selection signal. In the selected function, sliding compensation amount data corresponding to the speed of the object of positioning is read out. At least one of current position data and positioning target position data of the object is corrected by the read out sliding compensation amount data. A brake signal is generated on the basis of comparison of the current position data and target position data which have been subjected to this correction and a positioning control of the object is performed by this brake signal. On the other hand, a sliding amount detection circuit is provided for detecting sliding amount of the object from generation of the brake signal until actual stop of the object. The speed detected by a speed detector during generation of the brake signal is stored and, in accordance with the stored speed data and the detected sliding amount data, the selection signal for selecting the speed-sliding compensation amount function in the sliding compensation amount data memory is generated.

Positioning control system

Position of an object is detected by a position detector (10) and position data detected by this position detector is stored in a memory circuit (11). A time data supply section (21) supplies time data (.DELTA.t) as a lead compensation parameter. A compensation circuit (22) reads out position data (Dx (-.DELTA.T)) for a preceding time corresponding to the supplied time data (.DELTA.t) from the memory circuit (11) and corrects at least one of present position data (Dx) and target position data (Sx) in accordance with the difference between the read out position data and the present position data detected by the position detector thereby performing lead compensation. A control signal relating to the position of the object is generated in accordance with the present position data corrected by the compensation cirucit and the target position data and the positioning control is made by this control signal.

A coil assembly including primary coils disposed at predetermined locations axially spaced from one another and secondary coils provided in association with these primary coils is fixed at one end of a fluid powered cyliner. A piston rod is slidably disposed through a space in the primary and secondary coils. Rings made of magnetic substance are provided on the piston rod with a predetermined axial interval therebetween. Each of the primary coils is excited with one of reference AC signals which are out of phase with one another and an output signal which is electrically phase-shifted in accordance with the position of the piston rod is obtained as a sum of output signals from the secondary coils. Piston rod position data is obtained by measuring the amount of the phase-shifting and is utilized for positioning control of the cylinder. The velocity and acceleration of the movement of the piston rod are detected on the basis of the detected position data and the amount of overrun is estimated in accordance with the detected velocity and acceleration to effect the most accurate positioning control. Each time the positioning is completed, the amount of overrun is corrected to improve the accuracy of a next positioning control.

Positioning control system for a fluid powered cylinder

A rotational position, velocity and acceleration of an electrical motor are detected and an amount of overrun produced when the motor has stopped is estimated from the detected velocity and acceleration, and at least one of motor position detection data and a positioning target value is changed in accordance with the estimated amount of overrun. The position detection data and the positioning target value after the change are compared with each other and a command for stopping the motor is generated in accordance with a result of this comparison. A brake is applied to the motor in advance by the amount of the estimated overrun so that the motor is stopped at a desired target position after making overrun. Further, velocity setting signals are generated in accordance with desired acceleration and deceleration characteristics and the velocity control of the motor is effected in an open loop in response to the velocity setting signals. By the stop and velocity controls of an open loop system, positioning control of the motor of the open loop system can be accurately performed.

Growing community of inventors

Fuchu, Japan

Yasuhiro Yuasa