JPH06129806A - Rotational angle detection device - Google Patents

Abstract

PURPOSE:To improve the frequency of sampling timing irrespective of various conditions such as rotational speed and the like without complicating the configuration of circuit and thereby to improve the reliability of rotational angle detection device. CONSTITUTION:An output voltage Vout from a phase detection type resolver 1 is converted into a digital value by means of an A/D converter 33, and the value is voltage/phase converted by means of a phase converter 36 while an output from a positive/negative judgement unit 35 is considered, thereby rotational phase information theta is obtained. Based on a sampling signal phi set arbitralily from the outside sampling operation is made possible arbitralily and well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device using a variable reluctance resolver for detecting a rotation angle by changing the reluctance of a magnetic path according to the rotation angle.

[0002]

2. Description of the Related Art In a usage pattern (circuit configuration) of a rotation angle detection device using a resolver, a phase detection type which is excited by a two-phase signal to obtain a one-phase output signal and a two-phase output is obtained by one-phase excitation. There are two methods, a voltage detection type. Of these, the phase detection type has a simpler circuit configuration than the voltage detection type,
It is advantageous in terms of cost reduction.

In the case of a phase detection type resolver, for example, two-phase trigonometric function wave signals (sin ωt, cos ω) whose phases are shifted by 90 degrees are used.
At t), the stator is excited to obtain a one-phase output signal from the eccentric rotor. Specifically, as shown in FIG. 4, four exciting magnetic poles A, B, C, are provided on the inner peripheral portion of the hollow cylindrical stator 11 in the phase detection resolver 1.
D is provided and each of these exciting magnetic poles A,
An excitation coil (primary winding) 12 and a detection coil (secondary winding) 13 are wound around B, C, and D. Further, a cylindrical rotor 14 is eccentrically arranged inside the stator 11 such that a position O ′ deviated from the shape center O of the rotor 14 itself by a predetermined amount is an eccentric center of rotation. The air gap distance between the circumferential side surface and the tip surfaces of the exciting magnetic poles A, B, C, D on the stator 11 side, that is, the magnetic resistance, is configured to change as the eccentric rotor 14 rotates. There is.

Further, as shown in FIG. 5, the phase detection resolver 1 described above uses a sine wave using a digital signal (triangular wave shown in FIG. 6A) output from the ring counter 21. A two-phase excitation circuit 22 for generating a (sin wave) and a cosine wave (cos wave) is additionally provided, and from this two-phase excitation circuit 22 to the excitation coil (primary winding) 12 of the phase detection resolver 1 described above. Two-phase excitation voltage is being supplied. Of these, the sine wave (sin wave) shown in Fig. 6 (b)
Is a reference signal for the phase detection operation described later.

Here, when the rotation angle of the eccentric rotor 14 of the phase detection resolver 1 is θ, the output signal V _out (ωt · θ) from the phase detection resolver 1 is expressed by the following equation. . V _out = sin ωt · cos θ − cos ωt · sin θ = sin (ωt −θ)

That is, this resolver output signal V _out (=
sin (ωt−θ)) is obtained in a waveform whose phase is delayed by θ from the reference signal (sine wave shown in FIG. 6B), as shown in FIG. 6C. . This resolver output signal V _out passes through the comparator 23 and is shown in FIG.
And a rectangular wave, and is input to the latch circuit 24 as a sampling signal. On the other hand, in this latch circuit 24,
The ring counter 2 is applied with the output from the ring counter 21, and at the rising edge of the sampling signal, that is, at the time of zero crossing of the resolver output signal V _out.
A value of 1 is detected. Then, the position (phase) information is determined from this counter value.

In this way, the resolver output signal
The position (phase) information obtained at the time of crossing indicates the phase difference θ between the resolver output signal and the reference signal (one of the excitation signals, here a sine wave).

[0008]

As described above, in the resolver signal processing circuit according to the prior art, zero-cross detection of the resolver output signal is performed to detect the angle information from the phase difference θ, and the reference signal and the output signal are detected. A method is adopted in which the phase shift between and is counted by a counter or the like. Therefore, in such a conventional rotation angle detection device, there is a problem that the actual sampling (measurement) timing is limited to the zero cross point of the resolver output signal.

More specifically, the sampling interval T (FIG. 6), which is the repetition cycle of the above sampling timing, is used.
(See (d)) is expressed by the following equation corresponding to the rotation speed in the uniform angular velocity motion state. T = T _s (1 ± T _s · rotational speed [rpm] / 60) ⁻¹ where T _s is the period of the resolver excitation signal, and + and − in the above equation correspond to the rotation direction.

From the above equation, it can be seen that T = T _s is naturally in the stopped state, but in the rotating state, the sampling interval T extends or contracts depending on the rotation speed. Further, in a rotating state involving angular acceleration, the sampling interval T depends on time. Therefore, in order to increase the response characteristic of the servo system by making the sampling interval T close, the frequency of the excitation signal must be increased, which limits the flexibility of servo system design. Further, the sampling interval T does not have a constant value because it depends on the rotation state, which causes inconvenience in data communication and the like.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the prior art while taking advantage of the advantage of the phase detection type that the circuit configuration is simple and advantageous in cost reduction as compared with the voltage detection type. An object of the present invention is to provide a rotation angle detection device capable of sampling at timing.

[0012]

To achieve the above object, the first means according to the present invention has a plurality of pairs of exciting magnetic poles in which primary windings are differentially wound, and each exciting magnetic pole A stator having a secondary winding for extracting the induced voltage,
A rotor arranged so as to change the magnetic resistance between each of the exciting magnetic poles of the stator in accordance with the rotation, and each of the exciting magnetic poles of the stator is individually excited by a two-phase AC signal having a phase shift. Therefore, in the rotation angle detecting device configured to output the AC signal having a phase shift corresponding to the rotation angle of the rotor from the secondary winding, the reference of the two-phase excitation signals is used. A counter that outputs the excitation signal as a digital signal, an A / D converter that digitally exchanges the output from the secondary winding, and a positive / negative determination device that determines the positive / negative of the voltage at the output from the secondary winding. And a phase conversion means for receiving the outputs of the A / D converter and the positive / negative determination device and converting the output from the secondary winding into phase information. The second means according to the present invention provides a stator composed of two pairs of primary windings each excited by a two-phase excitation signal having a phase shift, and an induced voltage of one phase from the primary winding. Take out 2
A rotation angle detecting device comprising a rotor formed of a secondary winding, wherein an AC signal having a phase shift corresponding to the rotation angle of the rotor is output from the secondary winding. A counter that outputs a reference excitation signal of the excitation signals as a digital signal, a positive / negative determination device that determines whether the voltage at the output from the secondary winding is positive or negative, the A / D converter, and a positive / negative determination device. Phase conversion means for receiving the output from the secondary winding and converting the output from the secondary winding into phase information.

[0013]

In the means having such a structure, the sampling is carried out based on the sampling signal arbitrarily set from the outside, so that the rotational position information can be satisfactorily obtained regardless of various conditions such as the rotational speed. There is.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. The structure of the resolver itself may be either the variable reluctance type resolver shown in FIG. 4 or a so-called wire-wound resolver, and the variable reluctance type resolver will be described here as an example. However, detailed description of the structure of the resolver will be omitted, and a resolver signal processing circuit of the rotation angle detection device according to the present invention using the resolver will be described below.

As shown in FIGS. 1 and 2, the phase detection resolver 1 is provided with an exciting circuit including a ring counter 31 and a two-phase exciting circuit 32. The ring counter 31 outputs the triangular wave shown in FIG. 2A as a digital signal, and the digital signal output from the ring counter 31 is applied to the two-phase excitation circuit 32. , A sine wave excitation signal shown in FIG. 2B and a cosine wave (c not shown).
os wave) Excitation signal is generated. Each of the excitation signals from the two-phase excitation circuit 32 is supplied as a two-phase excitation voltage to the excitation coil (primary winding) 12 (see FIG. 4) of the phase detection resolver 1.
The sine wave shown in (b) is used as a reference signal for the phase detection operation described later.

The detection resolution is determined by the quantization density of the digital signal output from the ring counter 32 described above. For example, the angular resolution in the case of using a counter of 13 bits per cycle is 360 [degrees] / 13 bits, that is, 360 [degrees] / 13 bits = 360 [degrees] / 8192 = 0.044 [degrees] = 2.6 [minutes] The detection resolution of is obtained.

When the rotation angle of the eccentric rotor 14 (see FIG. 4) in the phase detection resolver 1 is θ, the output signal V _out (= sin (ωt −
2) is obtained as a sine waveform (voltage) whose phase is delayed by θ from the reference signal (the sine wave shown in FIG. 2B), as shown in FIG. 2C. . This resolver output signal V _out is _supplied to the A / D converter (A / D converter) 3
3 is converted into a digital value and the differentiating circuit 3
4 is input to the positive / negative determination unit 35 and the positive / negative of the differential coefficient
It is configured to obtain negative information.

Further, the output signals from the A / D converter 33 and the positive / negative decision device 35 are inputted to a phase converter 36, and the phase converter 36 outputs the resolver output signal V.
_By converting the digital value of _out into phase information, the rotational phase information of the eccentric rotor 14 is obtained. The rotational phase information obtained by the phase converter 36 is output as a triangular wave corresponding to the resolver output signal V _out as shown in FIG. A sampling signal φ is externally applied to the latch circuit 37 at an arbitrarily determined timing, and the rotation phase information θ ₀ at the arbitrary sampling time is applied to the calculator 38. The rotation phase information θ ₀ is obtained by using the correspondence table between the position and the output voltage in one cycle, and the position (phase) information is determined from an arbitrary voltage value.

As described above, in the rotation angle detecting device according to this embodiment, the output voltage from the phase detection resolver 1 is A
After being converted into a digital value by the A / D converter (A / D converter) 33, the value is subjected to data processing to determine which position in one cycle of the output voltage the value corresponds to. Is read. That is, the operation of determining the position (phase) information from an arbitrary voltage value using the correspondence table of the position and the output voltage in one cycle is performed by the digital circuit processing. This operation is just the ring counter 31
This is equivalent to the reverse operation of the process of generating a sine wave (sin wave) / cosine wave (cos wave) from the data of. The "position (phase) vs. voltage correspondence table" at this time may be quantized with the same division number as the ring counter 31, and in this embodiment, one cycle (one rotation) is divided into 13 bits (8192). There is.

At this time, since the output voltage changes in a sine wave shape, the voltage-to-phase information has a 2: 1 correspondence as it is, but the differential circuit 34 and the positive / negative discriminator 35 determine the positive / negative information of the differential coefficient. Is complementarily taken into consideration, so that a conversion of 1: 1 correspondence is possible.

The sampling signal φ at this time is
Since it is emitted at an arbitrary time as described above, the sampling cycle (interval) is arbitrarily set.

On the other hand, the output from the ring counter 31 is applied to the arithmetic unit 38 via another latch circuit 39. The sampling signal φ described above is simultaneously applied to the latch circuit 39 from the outside, and the value of the ring counter 31 at the time of sampling is the reference phase signal θ.
It is output as ₁ to the calculator 38.

The arithmetic unit 38 has a function of subtracting the reference phase signal θ ₁ from the ring counter 31 and the rotational phase information θ ₀ from the phase converter 36, and the phase difference θ between the two. By obtaining (θ = θ _I −θ ₀ ),
Rotation angle information indicating the current position of the resolver to be finally obtained is detected.

As described in the above-mentioned problems of the prior art, the cycle of the output voltage changes depending on the rotation state. This is especially true for each dividing element (Δθ) as shown in FIG. The time that stays at is only lengthened or shortened, and does not affect the measurement method at all.

As described above, according to the present signal processing method, since the sampling is performed based on the sampling signal φ arbitrarily set from the outside, the rotational position information can be satisfactorily obtained regardless of various conditions such as the rotational speed. .

The structure of the resolver to which the present invention is applied may be a so-called wire-wound resolver, and the resolver signal processing circuit as described above can be similarly used.

[0027]

As described above, the rotation angle detecting device according to the present invention uses the output voltage from the phase detecting resolver as A
The digital phase is converted by the D / D converter, and the data processing of the value is performed by the positive / negative judgment device and the phase converter so as to obtain the rotational phase information, and based on the sampling signal arbitrarily set from the outside. Since the sampling operation can be performed arbitrarily and satisfactorily, the frequency of sampling timing can be easily improved regardless of the conditions such as the rotation speed without complicating the circuit configuration. The reliability of the device can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a resolver signal processing circuit according to an embodiment of the present invention.

2 is a diagram showing operating signals of the circuit shown in FIG. 1. FIG.

FIG. 3 is a diagram showing an enlarged view of an area indicated by an arrow A in FIG.

FIG. 4 is a cross-sectional view showing a structural example of a phase detection resolver.

FIG. 5 is a block diagram of a conventional resolver signal processing circuit.

6 is a diagram showing operating signals of the circuit shown in FIG.

[Explanation of symbols]

 1 Resolver 31 Ring Counter 32 Two-Phase Excitation Circuit 33 A / D Converter (A / D Converter) 35 Positive / Negative Judgment Device 36 Phase Converter 38 Operation Unit

Claims (2)

[Claims] 1. A stator comprising a plurality of pairs of exciting magnetic poles in which primary windings are differentially wound, and a secondary winding for extracting an induced voltage by each exciting magnetic pole, and each exciting of the stator. A rotor arranged to change the magnetic resistance between the poles and the rotor with rotation, and each exciting magnetic pole of the stator is separately excited by a two-phase AC signal having a phase shift. In a rotation angle detecting device configured to output an AC signal having a phase shift corresponding to a rotation angle of a rotor from the secondary winding, a reference excitation signal of the two-phase excitation signals is used. , A counter for outputting as a digital signal, an A / D converter for digitally exchanging the output from the secondary winding, a positive / negative judging device for judging whether the voltage of the output from the secondary winding is positive or negative, D conversion And receiving the output of the positive and negative determination unit, and a phase conversion means for converting the output from the secondary winding to the phase information,
A rotation angle detecting device comprising: 2. A stator comprising two pairs of primary windings each excited by a two-phase excitation signal having a phase shift, and a secondary winding extracting a one-phase induced voltage from the primary winding. In the rotation angle detecting device, the AC signal having a phase shift corresponding to the rotation angle of the rotor is output from the secondary winding. A counter that outputs an excitation signal as a reference of the digital signal as a digital signal, a positive / negative judging device for judging whether the voltage of the output from the secondary winding is positive or negative, and outputs of the A / D converter and the positive / negative judging device. And phase conversion means for converting the output from the secondary winding into phase information,
A rotation angle detecting device comprising: