WO1986000401A1

WO1986000401A1 - Device for detecting absolute position

Info

Publication number: WO1986000401A1
Application number: PCT/JP1985/000361
Authority: WO
Inventors: Kenichi Toyoda; Tetsuro Sakano; Shinsuke Sakakibara; Yoshitaka Takekoshi
Original assignee: Fanuc Ltd
Priority date: 1984-06-26
Filing date: 1985-06-26
Publication date: 1986-01-16
Also published as: JPS6110715A

Abstract

A device for detecting absolute position employs a resolver (106) as position detector means. An interpolated error corresponding to the rotational angle of the rotary shaft of the resolver (106) is stored in advance in a data memory which consists of a bubble memory (102h) in a numerically controlled apparatus (102). When an absolute position is to be detected, the interpolated error of the resolver (106) is read out from the memory, and an absolute position signal detected by the resolver (106) is corrected by the interpolated error thereby to detect a correct absolute position.

Description

Details

Absolute position detector

Technical field

The present invention relates to an absolute position detecting device, and more particularly, to an absolute position detecting device capable of obtaining an accurate absolute position by minimizing an interpolation error of a resolver.

Background technology

A resolver, for example, a two-phase excitation type resolver is composed of a pair of stator windings SA and SB and a rotor winding RA as shown in FIG. Is connected to the rotation 回転 of the servomotor, and the rotor winding-RA is configured to be rotated in synchronization with the rotation of the servomotor. Then, a sine wave (sinot) is applied from the resolver excitation circuit 1 to one of the stator windings SA, and a cosine wave (c0sω0t) is applied to the other stator winding SB. Then, a sine wave si II (ω0t + θ) delayed by the mechanical angle ø of the rotor RA is output from the rotor winding RA. The phase difference ø between this sine wave output and the sine wave si η ω ο t applied to the stator winding SA is detected by the position detection circuit 2, and the pulse of the phase difference is counted. Then, it is output as position signal 0. In the related resolver, since a pair of stator windings SA and SB shown in FIG. 6 are required for the number of poles, a large number of stator windings are provided on the rotor winding RA of the resolver. It is necessary to arrange the data winding, and high accuracy of the arrangement is required. The resolver itself is generally miniaturized, and the stator windings are arranged with high accuracy. However, it is inevitable that an arrangement error, that is, an interpolation error is generated, and the phase of the output wave is shifted by the error. Due to the presence of such a resolver interpolation error, the conventional position detection system has the drawback that it is difficult to accurately detect the position of a controlled object. .

* The invention measures the resolver's characteristic curve to minimize the effect of the resolver's interpolation error, and can obtain an accurate absolute position based on this measurement result. The purpose of the present invention is to provide an absolute position detecting device capable of detecting an absolute position.

Disclosure of the invention

The present invention has position detecting means composed of a resolver connected to a movable part, and can be operated by a signal from the position detecting means. Means for storing an interpolation error of the resolver corresponding to the rotational position of the resolver, and an output signal of the resolver when the absolute position of the movable portion is detected by the resolver. And a means for compensating for the interpolation error stored in the means.

-In addition, measurement means for obtaining a characteristic curve data of the interpolation error of the resolver by rotating the resolver, and a description of data for storing the data on the characteristic curve in the bubble memory. And the value r read from the resolver when setting the reference point for absolute position detection. And Resorno interpolation error obtained from the measurement means. Absolute position detection reference value corrected based on and When obtaining the absolute position at an arbitrary point, the value 0 'read by the resolver at that time and the interpolation of the resolver obtained from the above-mentioned tilting means. A corrected value r of an arbitrary point obtained based on the error e ′, and the reference value r. And means for obtaining a corrected absolute position at an arbitrary point from the above, thereby providing an absolute position detecting device for obtaining an accurate absolute position of the servo control system. .

According to the present invention, it is possible to reliably correct the interpolation error despite the presence of the interpolation error inherent in the resolver, and to further improve the robot and machine tool. Thus, it is possible to accurately detect the position of the vehicle, etc., and thus to accurately perform the control of the position. Therefore, control reliability of robots, machine tools, etc. can be improved. In addition, the circuit configuration for such a purpose is only required to add a simple circuit to a part of the conventional NC device, and the increase in cost for expanding functions is small.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an overall block diagram of a servo control system to which an absolute position detection device according to the present invention is applied, and FIG. 2 is an embodiment of an absolute position detection signal input port in FIG. The circuit configuration diagram, Fig. 3 is a characteristic curve diagram for explaining the interpolation error of the resolver, Fig. 4 is the waveform diagram of each embodiment of Fig. 2, Fig. 5 (a) is the articulated π-bo the reference point position setting state of Bok 'side view illustrating, FIG. 5 (b) is similar articulated b Bo, the _y bets' side view showing an operating state at any point, Figure 6 is a conventional Multipolar resolver of It is a principle explanation .. It is a figure. '

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall block diagram of a servo control system to which the absolute position detecting device according to the present invention is applied. In the figure, 1 0 1 is

NC This is a paper tape on which the finger data is perforated, which stores finger positioning data such as positioning information for processing and M, S, and T function information. 1002 is 1 ^ (when the machine reads the NC data from the paper tape 101 using the tape reader puncher 102e described later from the paper tape 101. At the same time, it reads out the read NC data, and if it is an M, S, T function command, for example, sends the command to the machine side via a power board (not shown). If it is, the output is sent to the pulse distributor in the subsequent stage.The NC unit 102 is provided with a processor 102a that executes arithmetic processing in accordance with the control program and a predetermined number. A program memory 102 b for storing the control program, a data memory 102 c for storing the data, and an operation panel 102 d for operation. , Tape-danopancher 10 2 e, teaching operation panel 10-2 f, input / output port 10 2 g-, bubble memory 10 2 h, current position Counter 1 0 2 i, It consists of a position detection signal input port 102 j, a display device 102 k, and an address database 102 il .. 103 is a pulse S 蓥Performs a known pulse distribution calculation based on the movement command Zc to distribute the frequency according to the command speed. It generates a noise P. Numeral 104 is a distribution pulse train: a pulse train that accelerates the servomotor 105 linearly when Ps occurs and decelerates linearly at the end of the pulse train. A known acceleration / deceleration circuit for generating P i, 105 is a servomotor for driving the operation, for example, a movable part of an industrial robot is provided as a load . 106 is a resolver as position detecting means. Note that a speed reduction mechanism may be provided between the servomotor 105 and the resolver 106. Reference numeral 107 denotes an error display unit, which is composed of, for example, a reversible counter, and includes the number of input pulses P i generated from the acceleration / deceleration circuit 104 and the number of fields. The error E r from the pulse FPI obtained by debugging is recorded. Note that the error calculation memory section 107 may be composed of a memory circuit 107a shown in the figure and an error register 107b for storing the error Er. . Reference numeral 108 denotes a digital analog (DA) converter for generating an analog voltage proportional to the contents of the error register 107 b, and 109 denotes a speed control circuit. . Note that the error operation storage unit 107 and the DA converter 108 constitute a motor's position control circuit.

In particular, in the present invention, the resolver 106 is rotated to obtain the characteristic curve of the interpolation error of the resolver 106 as shown in FIG. 3, and the data relating to the characteristic curve is obtained. For example, the interpolation error e ′ with respect to the rotation angle of the resolver 106 is stored in the bubble memory 1.02h, and when setting the grave reference point for absolute position detection, ie, When setting the resin value, The reference value for absolute position detection in which the interpolation error of the resolver 106 has been corrected from the value r ₀ ′ (see FIG. 3) read from the buffer 106 and the data obtained by the measurement. Let's get r 0.

Further, when obtaining the absolute position at an arbitrary point, the value r ′ read by the resolver at the arbitrary point and the resolver obtained from the measurement data are interpolated. A corrected absolute position at an arbitrary point is obtained from a corrected value r of an arbitrary point obtained using the error s' and the reference value r0.

This will be described in more detail.

First, the operation of the operation panel is used to set the interpolation error translation mode of the resolver, and the resolver 106 is rotated to determine the interpolation error. That is, by the rotation of the resolver 106, the output wave sin (ω0t + Θ + Θ ') of the rotor winding RA shown in FIG. 6 (where 0' is the interpolation error ), The sine wave sincoot applied to the stator winding SA is input to the position detection signal input port 102j shown in Fig. 1.

FIG. 2 is a circuit diagram of an embodiment of such a position detection signal input port.

In the figure, reference numerals 20 and 21 denote zero slice circuits, each of which is composed of a comparator. Each of the output waves of the line RA is si it · (ω 0 t + θ + θ '), the sine wave si · η ω ot applied to the data winding S' A is zero-volt sliced and converted into a ^ shape wave, T 2 (see Fig. 4). You 2 2, 2 3 The § Li in the rising re-detection circuit, each rectangular wave, to detect the rising Li of T 2, Ri Oh the rising Pulse T s, also you output of T ₄ of Roh Tsu door gate 2a, a pair of shift registers 22b and 22c, and an AND gate 22d. 2 4 Ri Oh in a non-Clip and non-Russia-up, start-up Li Roh, * ls e T s in the Li cell Tsu door, rising Pulse T ₄ Dese Tsu is Bok, corresponding to the phase difference The gate signal 5 is output. 2 5 Ri gate circuit der, it forces out of the click lock Bal scan CLK to the output period of the Gate signal Τ _5. Numeral 26 denotes a counter which counts the clock pulse CLK from the gate circuit 25 and rises, and is reset by the pulse T4. . The output from the counter 26 is output to the address data bus 10 (see Fig. 1). Also, rising Pulse T _s is likewise A de Re vinegar, is output to the data bus.

Therefore, the output signal from the counter 26 is written in the address memory 102h via the address and the data bus 102A. .

Next, correction of the interpolation error 0 'output from the resolver 106 will be described.

The relationship between the phase difference of the resolver '106 and the interpolation error e, that is, the correction value 0', is as shown in Fig. 3, and the relationship between the phase difference of the resolver '106 and that of the resolver 106 is as follows. The error of the sampled phase difference is measured and stored in the memory 1h.

Next, a reference point for detecting the absolute position of, for example, an articulated robot connected to the servomotor 105, ie, an origin. Configure the settings from the operation panel. FIG. 5 (a) is a diagram showing an origin value setting state of such an articulated robot. In the figure, 1 is a W-axis unit, 2 is a W arm, 2a is a bearing, 3a is a bearing, and 4 is a wrist mechanism.

The origin setting of this articulated robot can be performed by driving the servomotor 105 to the W arm 2 so that it is vertical.

Therefore, the resolver 106 was read when setting this origin. Assume that the read value at this time is r 0-(see Fig. 3). On the other hand, the interpolation error e0 of the resolver stored in the above bubble memory corresponding to the time of setting the origin is calculated from the bubble memory 102h by the address memory. Data path

Output on the A 102 A, and subtract the interpolation error s 0 from the 刖 C embedded value Γ 0 by the CPU 102 a to detect the corrected absolute position detection of the origin setting position. Reference value r. Ask for.

Next, as shown in Fig. 5 (b), to determine the absolute position of the arm of the articulated σ e, y at a given point, it is necessary to determine the absolute position at that point. From the read value r 'from the solver 106, the resolution to the arbitrary point stored in the pre-memory 102h, and the interpolation error e of the rubber 106 from the read memory 102h 'Is subtracted to find the complemented value r. Thus, an accurate absolute position at an arbitrary point is obtained from the obtained correction value r and the reference value r0 described above.

In Fig. 1, although only one type of servo control is described, it can be said that it can be applied to multiple type control. Not surprising. Although the servomotors 1 and 5 show the movable parts of the bots as loads, the movable parts of various machines with NC devices such as machine tools can be connected.

Industrial applicability

* The absolute position detection device is applicable not only to the absolute position detection of a servo system including a numerical control device but also to any position detection device using a resolver.

Claims

0-Scope of claim

(1) An absolute position detecting device having position detecting means composed of a resolver connected to a movable part and detecting an absolute position of the movable part by a signal from the position detecting means includes the following:

a, means for storing the interpolation error of the resolver corresponding to the rotational position of the resolver;

b, means for correcting the output signal of the resolver based on the interpolation error stored in the storage means when the absolute position of the movable part is detected by the resolver.

(2) An absolute position detecting device which has a position detecting means composed of a resolver connected to a movable city and detects an absolute position of the movable part by a signal from the position detecting means includes the following:

a, interpolation error measuring means for rotating the resolver and translating the interpolation error of the resolver;

b, data storage means for storing data obtained by the measurement means;

c, The value read from the resolver when setting the reference point for absolute position detection! : 'And the interpolation error S of the resolver obtained from the above-mentioned means. Means for obtaining a reference value Γ Q for absolute position detection corrected based on and

d, when calculating the absolute position at an arbitrary point, the value Γ 'read by the resolver at that time and the resolver interpolation error obtained from the above-mentioned means. A corrected value の of any point obtained based on € 'and the reference value Γ. And any from 1 Means for finding the corrected absolute position at one point.

(3) The absolute position detecting device according to the above (1) or (2), wherein the storage device is a bubble memory.