CN102636194B - Orthogonal sine and cosine axial angle encoder signal detecting and converting circuit - Google Patents

Abstract

The signal detection and conversion circuit of the quadrature positive and cosine shaft angle encoders of the present invention includes: a single-chip microcomputer module, an interval discrimination circuit and an encoder. The circuit can convert the quadrature positive and cosine wave shaft angle signal values output by the encoder into pulse train signals that can be used to calculate the motor speed and position. The single-chip microcomputer module calculates the angle value according to the signal amplitude of the encoder and the signal output by the interval discrimination circuit. If the calculated angle value is in the first half of the square wave pulse signal cycle, it will output a high level. On the contrary, it will output a low level in the second half cycle. level, thus forming an orthogonal pulse train corresponding to the sine and cosine signals. The calculation of the angle is calculated by the linear function approximation method within the allowable range of the error. This circuit is suitable for feedback and collection of motor running speed and position information in a servo system. It has the characteristics of less computing resources occupied, low hardware cost, fast detection and conversion speed, and high precision.

Description

Orthogonal positive and cosine shaft angle encoder signal detection and conversion circuit

technical field

The invention relates to a signal detection and conversion circuit of an orthogonal positive and cosine shaft angle encoder, which belongs to the technical field of servo motor control.

Background technique

The servo system, also known as the servo system, needs to detect the relative position and change of the motor rotor and the rotor and stator in real time. The detection accuracy of the rotor position determines the control performance of the servo motor. In recent years, the application of sine and cosine wave signal encoders in high-precision servo systems has gradually increased due to their relatively low cost and the advantages of high-precision speed and position detection accuracy. Usually, the signal of this type of encoder is obtained through an optical slit or using a Hall magnetic element. The original signal is the sine and cosine function of the rotor angular position, and the phase difference between the sine and cosine is 90 degrees. It is measured by using a pulse counter The number of sine or cosine waves can get the angle value, but the motor can only get the number of pulses equal to the number of sine waves per revolution, so the detection accuracy is low. In order to improve the speed and position detection accuracy of the sinusoidal signal encoder, making it suitable for high-performance servo systems, many detection and conversion circuits and methods have been applied, but generally DSP and FPGA are used as the control core, and large storage is required in the periphery. unit, the hardware cost is high, and the calculation amount is large.

Contents of the invention

The purpose of the present invention is to provide a signal detection and conversion circuit for quadrature and cosine shaft angle encoders suitable for servo systems, low in price, high in cost performance, fast in detection and conversion speed and high in precision.

The signal detection and conversion circuit of the orthogonal positive and cosine shaft angle encoders of the present invention includes: a single-chip microcomputer module, an interval discrimination circuit and an encoder; the interval discrimination circuit is composed of a sine signal interval discrimination circuit and a cosine signal interval discrimination circuit, and the encoder outputs The sine signal is connected with the first input and output I/O port of the single-chip microcomputer module and the signal input end of the sine signal interval discrimination circuit, and the cosine signal output by the encoder is connected with the second input and output I/O port and the cosine signal of the single-chip microcomputer module respectively. The signal input end of interval discrimination circuit is connected; The interval signal of sine signal interval discrimination circuit output is connected with the third input and output I/O port of single-chip microcomputer module, and the interval signal of cosine signal interval discrimination circuit output is connected with the fourth input and output I of single-chip microcomputer module. The /O port is connected, and the fifth input and output I/O port of the single-chip microcomputer module is the output end of the orthogonal pulse train;

The above-mentioned sinusoidal signal interval discrimination circuit comprises the first operational amplifier chip, the first voltage comparison chip and corresponding peripheral components; 2 pins of the first operational amplifier chip are connected in total with one end of the resistor R1, the resistor R2 and the resistor R101, and the first computing Pin 3 of the amplifier chip is connected to one end of resistor R3, the other end of resistor R3 is connected to one end of capacitor C1 and grounded, the other end of capacitor C1 is connected to the other end of resistor R1, and this connection point is the signal of the sine signal interval discrimination circuit Input terminal; the other end of the resistor R101 is connected to the DC bias voltage VB, the other end of the resistor R2 is connected to pin 1 of the first operational amplifier chip, the positive pole of the diode D1, the negative pole of the diode D2, one end of the resistor R7, the resistor R14 and the resistor R9 One end is connected together, pins 4 and 11 of the first operational amplifier chip are respectively connected to +15V and -15V voltages, the cathode of diode D1 is connected to one end of resistor R8 and DC voltage VCC, the anode of diode D2 is connected to ground, and the cathode of resistor R8 The other end is connected with one end of the resistor R12 and pin 7 of the first voltage comparison chip, the other end of the resistor R12 is connected with one end of the resistor R11 and pin 5 of the first voltage comparison chip, and the other end of the resistor R11 is connected with one end of the resistor R13 and The pin 9 of the first voltage comparison chip is connected, the other end of the resistor R13 is connected to the ground, the other end of the resistor R7 is connected to the pin 6 of the first voltage comparison chip and one end of the resistor R4, and the other end of the resistor R4 is connected to the anode of the diode D3 Connected, the cathode of diode D3 is connected to pin 1 of the first voltage comparison chip, one end of resistor R5 and one end of resistor R6, the other end of resistor R5 is connected to +15V voltage, the other end of resistor R6 is connected to the positive electrode of diode D5 and the diode The negative pole of D4 is connected, and this connection point is connected with the third input and output I/O port of the single-chip microcomputer module; the other end of the resistor R9 is connected with the pin 4 of the first voltage comparison chip and one end of the resistor R15, and the other end of the resistor R15 is connected with the diode The positive pole of D6 is connected, the negative pole of diode D6 is connected with pin 2 of the first voltage comparison chip, one end of resistor R16 and one end of resistor R17, the other end of resistor R16 is connected to +15V voltage, the other end of resistor R17 is connected with the diode D7 The positive pole is connected to the negative pole of the diode D8, and this connection point is connected to the third input and output I/O port of the single-chip microcomputer module; the other end of the resistor R14 is connected to pin 8 of the first voltage comparison chip and one end of the resistor R10, and the other end of the resistor R10 One end is connected to the positive pole of diode D9, the negative pole of diode D9 is connected to pin 14 of the first voltage comparison chip, one end of resistor R18 and one end of resistor R19, the other end of resistor R18 is connected to +15V voltage, the other end of resistor R19 is connected to The positive pole of the diode D10 is connected to the negative pole of the diode D11, and this connection point is connected to the third input and output I/O port of the single-chip microcomputer module; pins 3 and 12 of the first voltage comparison chip are respectively connected to +15V and -15V voltages;

The above-mentioned cosine signal interval discrimination circuit comprises a second operational amplifier chip, a second voltage comparison chip and corresponding peripheral components; 2 pins of the second operational amplifier chip are connected in total with one end of the resistor R1 ', the resistor R2 ' and the resistor R101 ', Pin 3 of the second operational amplifier chip is connected to one end of the resistor R3', the other end of the resistor R3' is connected to one end of the capacitor C1' and grounded, and the other end of the capacitor C1' is connected to the other end of the resistor R1'. It is the signal input end of the cosine signal interval discrimination circuit; the other end of the resistor R101' is connected to the DC bias voltage VB, the other end of the resistor R2' is connected to pin 1 of the second operational amplifier chip, the positive pole of the diode D1', and the negative pole of the diode D2' 1, one end of resistor R7', one end of resistor R14' and one end of resistor R9' are connected together, pins 4 and 11 of the second operational amplifier chip are respectively connected to +15V, -15V voltage, the negative pole of diode D1' is connected to one end of resistor R8' It is connected to the DC voltage VCC, the anode of the diode D2' is connected to the ground, the other end of the resistor R8' is connected to one end of the resistor R12' and pin 7 of the second voltage comparison chip, and the other end of the resistor R12' is connected to one end of the resistor R11' The other end of the resistor R11' is connected to one end of the resistor R13' and the pin 9 of the second voltage comparison chip, the other end of the resistor R13' is connected to the ground, and the other end of the resistor R7' It is connected to pin 6 of the second voltage comparison chip and one end of resistor R4', the other end of resistor R4' is connected to the positive pole of diode D3', and the negative pole of diode D3' is connected to pin 1 of the second voltage comparison chip and resistor R5'. One end is connected to one end of resistor R6', the other end of resistor R5' is connected to +15V voltage, the other end of resistor R6' is connected to the positive pole of diode D5' and the negative pole of diode D4', this connection point is connected to the fourth The input and output I/O ports are connected; the other end of the resistor R9' is connected to the pin 4 of the second voltage comparison chip and one end of the resistor R15', the other end of the resistor R15' is connected to the positive pole of the diode D6', and the negative pole of the diode D6' Connect to pin 2 of the second voltage comparison chip, one end of resistor R16' and one end of resistor R17', the other end of resistor R16' is connected to +15V voltage, the other end of resistor R17' is connected to the anode of diode D7' and diode D8 ’, the connection point is connected to the fourth input and output I/O port of the single chip microcomputer module; the other end of the resistor R14’ is connected to the pin 8 of the second voltage comparison chip and one end of the resistor R10’, and the other end of the resistor R10’ One end is connected to the positive pole of diode D9', the negative pole of diode D9' is connected to pin 14 of the second voltage comparison chip, one end of resistor R18' and one end of resistor R19', the other end of resistor R18' is connected to +15V voltage, and the resistor The other end of R19' is connected to the positive pole of diode D10' and the negative pole of diode D11', and this connection point is connected to the fourth input and output I/O port of the single-chip microcomputer module; pins 3 and 12 of the second voltage comparison chip are respectively connected to +15V, -15V voltage.

The section discriminant circuit in the present invention divides each sine wave period [0, 2π] into 8 sections according to the angle width π/4 of each section after the sine wave signal is amplified and adjusted, and outputs It can be used to judge the high and low level signals of the interval. The single-chip microcomputer module divides the interval with a width of π/4 into N equal parts (N is a positive integer, each equal is divided into a square wave pulse signal period), and then judges the output signal of the circuit according to the signal amplitude of the encoder and the interval , to calculate the corresponding angle value. If the calculated angle value is in the first half of the square wave pulse signal cycle, it will output a high level, and on the contrary, it will output a low level in the half cycle, thereby forming a pulse train corresponding to the sine and cosine signals. The calculation of the angle adopts the linear function approximation method within the allowable range of the error.

The beneficial effects of the present invention are:

The orthogonal positive and cosine shaft angle encoder signal detection and conversion circuit of the present invention has low hardware cost, occupies less computing resources, has fast detection and conversion speed and high precision, and can be conveniently used for estimating motors with positive and cosine shaft angle encoders The operating position, direction of rotation and speed of movement of the rotor are applicable to most servo systems. It is especially suitable for servo systems that require high speed accuracy detection, such as high-precision CNC machine tool table servo feed system, radar antenna automatic tracking system, photoelectric precision tracking system, low-speed servo system, etc.

Description of drawings

Figure 1 is a schematic diagram of the signal detection and conversion circuit of the quadrature positive and cosine shaft-angle encoders.

Fig. 2 is a circuit diagram of a sinusoidal signal interval discrimination.

Fig. 3 is a circuit diagram of cosine signal interval discrimination.

Figure 4 SCM module diagram.

Figure 5 is the corresponding interval distribution diagram of sine and cosine functions.

Fig. 6 is a schematic diagram of the output of orthogonal pulse trains A and B, wherein: a) the picture shows the pulse train A, and b) the picture shows the pulse train B.

Detailed ways

The implementation method and principle of the present invention will be further described below in conjunction with examples and accompanying drawings.

With reference to Fig. 1, quadrature positive of the present invention, cosine axis angle encoder signal detection and conversion circuit comprise: single-chip microcomputer module 1, interval discrimination circuit 2 and encoder 3; Interval discrimination circuit 2 is made of sine signal interval discrimination circuit 2-1 and The cosine signal interval discrimination circuit 2-2 is formed, and the sine signal Y1 output by the encoder 3 is connected with the first input and output I/O port of the single-chip microcomputer module 1 and the signal input end of the sine signal interval discrimination circuit 2-1, and the encoder 3 The output cosine signal Y2 is connected with the signal input end of the second input and output I/O port of the single-chip microcomputer module 1 and the signal input end of the cosine signal interval discrimination circuit 2-2 respectively; The third input and output I/O port of the single-chip microcomputer module 1 is connected to each other, and the interval signal output by the cosine signal interval discrimination circuit 2-2 is connected to the fourth input and output I/O port of the single-chip microcomputer module 1, and the fifth input and output I/O port of the single-chip microcomputer module 1 It is the output terminal of orthogonal pulse train A and B.

The single-chip microcomputer module adopts the C8051F330/1 single-chip microcomputer of Cygnal Company (see Figure 4), the single-chip microcomputer has 17 input/output I/O pins, and each pin can be configured as an analog or digital input/output I/O port, 1 A 16-bit counter, a 10-bit analog/digital converter ADC. In this example, the first input and output I/O port is composed of the P1.7 pin of the microcontroller; the second input and output I/O port is composed of the P1.6 pin of the microcontroller; the third input and output I/O port is composed of the single chip microcomputer P1.0, P1.1, P1.2 pins; the fourth input and output I/O port is composed of P1.3, P1.4, P1.5 pins of the microcontroller; the fifth input and output I/O port is composed of Composed of P0.4 and P0.5 pins of the microcontroller.

The sinusoidal signal interval discrimination circuit is shown in Figure 2, comprising the first operational amplifier chip U1, the first voltage comparison chip U2 and corresponding peripheral components; the 2 pins of the first operational amplifier chip U1 and the resistor R1, resistor R2 and resistor R101 One end is connected together, pin 3 of the first operational amplifier chip U1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the capacitor C1 and grounded, and the other end of the capacitor C1 is connected to the other end of the resistor R1. It is the signal input end of the sinusoidal signal interval discrimination circuit; the other end of the resistor R101 is connected to the DC bias voltage VB, the other end of the resistor R2 is connected to pin 1 of the first operational amplifier chip U1, the positive pole of the diode D1, the negative pole of the diode D2, and the resistor R7 One end of the resistor R14 and one end of the resistor R9 are connected together, pins 4 and 11 of the first operational amplifier chip U1 are respectively connected to +15V and -15V voltages, the cathode of the diode D1 is connected to one end of the resistor R8 and the DC voltage VCC, and the diode The positive pole of D2 is connected to ground, the other end of resistor R8 is connected to one end of resistor R12 and pin 7 of the first voltage comparison chip U2, and the other end of resistor R12 is connected to one end of resistor R11 and pin 5 of the first voltage comparison chip U2 , the other end of the resistor R11 is connected to one end of the resistor R13 and pin 9 of the first voltage comparison chip U2, the other end of the resistor R13 is connected to the ground, the other end of the resistor R7 is connected to the pin 6 of the first voltage comparison chip U2 and the resistor R4 One end of the resistor R4 is connected to the positive pole of the diode D3, the negative pole of the diode D3 is connected to pin 1 of the first voltage comparison chip U2, one end of the resistor R5 and one end of the resistor R6, and the other end of the resistor R5 is connected to + 15V voltage, the other end of the resistor R6 is connected to the positive pole of the diode D5 and the negative pole of the diode D4, and the connection point S1 is connected to the third input and output I/O port of the single-chip microcomputer module; the other end of the resistor R9 is connected to the first voltage comparison chip U2 Pin 4 of the resistor R15 is connected to one end of the resistor R15, the other end of the resistor R15 is connected to the positive pole of the diode D6, the negative pole of the diode D6 is connected to the pin 2 of the first voltage comparison chip U2, one end of the resistor R16 and one end of the resistor R17, and the resistor R16 The other end of the resistor R17 is connected to the +15V voltage, the other end of the resistor R17 is connected to the positive pole of the diode D7 and the negative pole of the diode D8, and the connection point S2 is connected to the third input and output I/O port of the microcontroller module; the other end of the resistor R14 is connected to the Pin 8 of the first voltage comparison chip U2 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the positive pole of the diode D9, and the negative pole of the diode D9 is connected to pin 14 of the first voltage comparison chip U2, one end of the resistor R18 and the resistor R19 One end of the resistor R18 is connected to the +15V voltage, the other end of the resistor R19 is connected to the positive pole of the diode D10 and the negative pole of the diode D11, and the connection point S3 is connected to the third input and output I/O port of the single-chip microcomputer module; Pins 3 and 12 of the first voltage comparison chip U2 are respectively connected to voltages of +15V and -15V.

The cosine signal interval discrimination circuit is shown in Figure 3, including the second operational amplifier chip U1', the second voltage comparison chip U2' and corresponding peripheral components; the 2 pins of the second operational amplifier chip U1' and the resistor R1', the resistor R2 ' and one end of the resistor R101' are connected together, the pin 3 of the second operational amplifier chip U1' is connected to one end of the resistor R3', the other end of the resistor R3' is connected to one end of the capacitor C1' and grounded, and the other end of the capacitor C1' Connect to the other end of the resistor R1', which is the signal input end of the cosine signal interval discrimination circuit; the other end of the resistor R101' is connected to the DC bias voltage VB, and the other end of the resistor R2' is connected to the second operational amplifier chip U1' Pin 1, the positive pole of diode D1', the negative pole of diode D2', one end of resistor R7', one end of resistor R14' and one end of resistor R9' are connected together, and pins 4 and 11 of the second operational amplifier chip U1' are respectively connected to +15V , -15V voltage, the cathode of the diode D1' is connected to one end of the resistor R8' and the DC voltage VCC, the anode of the diode D2' is connected to the ground, the other end of the resistor R8' is connected to one end of the resistor R12' and the second voltage comparison chip U2 ’, the other end of the resistor R12’ is connected to one end of the resistor R11’ and the 5 pin of the second voltage comparison chip U2’, the other end of the resistor R11’ is connected to one end of the resistor R13’ and the second voltage comparison chip U2 ’, the other end of the resistor R13’ is connected to the ground, the other end of the resistor R7’ is connected to the 6 pin of the second voltage comparison chip U2’ and one end of the resistor R4’, and the other end of the resistor R4’ is connected to the diode D3 ' is connected to the positive pole, the negative pole of the diode D3' is connected to pin 1 of the second voltage comparison chip U2', one end of the resistor R5' and one end of the resistor R6', the other end of the resistor R5' is connected to +15V voltage, and the resistor R6' The other end of the resistor R9' is connected to the positive pole of the diode D5' and the negative pole of the diode D4', and the connection point S1' is connected to the fourth input and output I/O port of the single-chip microcomputer module; the other end of the resistor R9' is connected to the second voltage comparison chip U2' Pin 4 of the resistor R15' is connected to one end of the resistor R15', the other end of the resistor R15' is connected to the positive pole of the diode D6', the negative pole of the diode D6' is connected to pin 2 of the second voltage comparison chip U2', one end of the resistor R16' and the resistor R17 ', the other end of the resistor R16' is connected to +15V voltage, the other end of the resistor R17' is connected to the positive pole of the diode D7' and the negative pole of the diode D8', and the connection point S2' is connected to the fourth input and output of the single-chip microcomputer module The I/O port is connected; the other end of the resistor R14' is connected to the pin 8 of the second voltage comparison chip U2' and one end of the resistor R10', the other end of the resistor R10' is connected to the positive pole of the diode D9', and the negative pole of the diode D9' Connect with pin 14 of the second voltage comparison chip U2', one end of the resistor R18' and one end of the resistor R19', the other end of the resistor R18' is connected to +15V voltage, the other end of the resistor R19' is connected to the anode of the diode D10' and two The negative electrode of the pole tube D11' is connected, and the connection point S3' is connected with the fourth input and output I/O port of the single-chip microcomputer module; pins 3 and 12 of the second voltage comparison chip U2' are respectively connected to +15V and -15V voltages.

The first operational amplifier chip in the sine signal interval discrimination circuit and the second operational amplifier chip in the cosine signal interval discrimination circuit all adopt TL084 chip, the first voltage comparison chip in the sine signal interval discrimination circuit and the cosine signal interval discrimination circuit in the first voltage comparison chip The second voltage comparison chips all use LM339 chips,

The voltage threshold of the sine/cosine signal interval discrimination circuit is obtained by dividing the voltage of the resistor, and the diode in the circuit plays the role of limiter and protection. The interval discrimination circuit outputs high and low level combination signals according to the magnitude of the sine and cosine signals, and inputs them into the single-chip microcomputer.

The working principle of the interval discrimination circuit (see Table 1): each sine wave cycle [0, 2π] can be divided into 8 intervals (as shown in Figure 5), and the width of each interval is π/4. Lines 1-4 in Table 1 correspond to the values of sine and cosine signals y ₁ , y ₂ and interval numbers and angles. The quadrature positive and cosine signal values output by the encoder are adjusted to Y ₁ =(VCC/2)sinθ+VCC/2 and Y ₂ =(VCC/2)cosθ+VCC/2 after being adjusted by the arithmetic circuit. The threshold value of the voltage comparison chip is respectively set to Corresponding to three points of a, b, c in Fig. 2 and three points of a', b', c' in Fig. 3, (wherein a is the 7-pin connection point of resistor R8, resistor R12 and first voltage comparison chip U2 , b is the connection point between resistor R11 and resistor R12 and the pin 5 of the first voltage comparison chip U2, c is the connection point between resistor R11 and resistor R13 and the pin 9 of the first voltage comparison chip U2; a' is the connection point between resistor R8' and resistor R12 'and the 7-pin connection point of the second voltage comparison chip U2', b' is the 5-pin connection point of the resistance R11' and the resistance R12' and the second voltage comparison chip U2', c' is the resistance R11' and the resistance R13' and The second voltage is compared to the 9-pin connection point of the chip U2'). The values of a, b, and c corresponding to _y1 in Table 1 are respectively The values of _y2 in Table 1 corresponding to a', b' and c' are respectively When the signal value exceeds the threshold value, the corresponding voltage comparison chip outputs a low level, and when the signal value does not exceed the threshold value, the voltage comparison chip outputs a high level. The fifth and sixth lines in Table 1 correspond to the output level of the interval discrimination circuit and the interval number. In the table, "1" means high level, and "0" means low level.

Table 1 Interval discrimination circuit principle

The working principle of the single chip microcomputer module is as follows:

When the motor rotates, the encoder outputs quadrature positive and cosine signals, and the A/D converter in the single-chip microcomputer C8051F330/1 samples the signal in real time, and the sampled signal function value

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; B</span>}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; B</span>}\end{array}\right.$

Among them, A is the amplitude of the encoder output signal, and B is the offset, which is obtained after per unit calculation

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ {\mathrm{<span\; class="notranslate">\; Y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right.$

According to the interval number of the interval judgment circuit, select the curve segment shown by the thick black line in Figure 5 from the sine and cosine wave signals as the source value of the signal conversion. As shown in Figure 6, the interval [0, π/4] is divided into N equal parts (N is a positive integer), each equal is divided into a square wave pulse period, and the angle calculated according to the corresponding linear function in Table 2 If the value is in the first half of the cycle, the output is high level, and on the contrary, the second half cycle is low level, thus forming pulse train A (see Figure 6a)). Assuming that the angle calculated from the signal value is θ _m , set M=8Nθ _m /π, round M, if the result is 0 or an even number, output a high level, and if it is an odd number, output a low level. For pulse train B (see Figure 6b)), it is only necessary to move forward the period interval corresponding to pulse A by 1/4 of the pulse period, that is, take M ₁ =M+0.5, and then round M ₁ to an integer, the same result If it is 0 or an even number, it will output a high level, if M ₁ is an odd number, it will output a low level.

Table 2 Intervals and corresponding linear functions

The linear function is as follows:

y=kθ (1)

y＝-k(θ--π/2) (2)

y＝-k(θ-π) (3)

y=k(θ-3π/2) (4)

y=k(θ-2π) (5)

The calculation of the angle value adopts the linear function approximation method corresponding to Table 2, and the error of the approximation is analyzed below. In Fig. 6, the sinusoidal signal function is y ₁ =sin θ, the linear function y=kθ, k=sin(π/4)/(π/4)0.9002, let Δy=y ₁ -y, at θ=[0, π/4] interval, the maximum value of Δy is 0.02988, at this time θ=0.4504 radians, y ₁ =0.4352, y=0.4054. Here, let y=y ₁ =0.4352, substituting it into the formula y=kθ can calculate the corresponding angle as 0.4834 radians, that is to say, in the interval of θ=[0, π/4], the positive and cosine functions can be used as linear linear functions If y is approximated, a maximum error of 0.03 radians will be generated. Just take a positive integer of N≤(π/4)/0.03≈26.2, and the error generated by the approximation is within the period of a pulse signal, that is, the error is smaller than that of the entire sensor. The detection accuracy is negligible, but the method of calculating the angle with a linear straight line function greatly simplifies the algorithm. According to the above method, assuming that the number of sine and cosine wave signals output by the encoder is K for one revolution of the motor rotor, the algorithm can output 8*KN square wave pulse signals within one revolution. Generally, the K of the encoder is between 100 and 1000, and the pulse train output by the circuit can reach 20800 to 208000 pulses per revolution, which can fully meet the detection requirements of the high-precision servo system.

Claims (1)

1. Orthogonal positive, cosine shaft angle encoder signal detection and conversion circuit, it is characterized in that comprising: single-chip microcomputer module (1), interval discrimination circuit (2) and encoder (3); Interval discrimination circuit (2) is made up of sinusoidal signal Interval discrimination circuit (2-1) and cosine signal interval discrimination circuit (2-2), the sine signal (Y1) output by the encoder (3) is connected with the first input and output I/O port of the single chip microcomputer module (1) and The signal input terminal of the sine signal interval discrimination circuit (2-1) is connected, and the cosine signal (Y2) output by the encoder (3) is respectively connected to the second input and output I/O port of the single-chip microcomputer module (1) and the cosine signal interval discrimination circuit The signal input terminals of (2-2) are connected; the interval signal output by the sine signal interval discrimination circuit (2-1) is connected with the third input and output I/O port of the single-chip microcomputer module (1), and the cosine signal interval discrimination circuit (2- 2) The output interval signal is connected to the fourth input and output I/O port of the single-chip microcomputer module (1), and the fifth input and output I/O port of the single-chip microcomputer module (1) is an orthogonal pulse train (A), (B) output terminal; The above-mentioned sinusoidal signal interval discrimination circuit includes a first operational amplifier chip (U1), a first voltage comparison chip (U2) and corresponding peripheral components; pin 2 of the first operational amplifier chip (U1) and resistor R1, resistor R2 and resistor One end of R101 is connected together, pin 3 of the first operational amplifier chip (U1) is connected to one end of resistor R3, the other end of resistor R3 is connected to one end of capacitor C1 and grounded, and the other end of capacitor C1 is connected to the other end of resistor R1 , the connection point is the signal input end of the sinusoidal signal interval discrimination circuit; the other end of the resistor R101 is connected to the DC bias voltage VB, the other end of the resistor R2 is connected to pin 1 of the first operational amplifier chip (U1) and the anode of the diode D1, the diode The negative pole of D2, one end of resistor R7, one end of resistor R14 and one end of resistor R9 are connected together, pins 4 and 11 of the first operational amplifier chip (U1) are respectively connected to +15V and -15V voltages, the negative pole of diode D1 is connected to the pin of resistor R8 One end is connected to DC voltage VCC, the anode of diode D2 is connected to ground, the other end of resistor R8 is connected to one end of resistor R12 and pin 7 of the first voltage comparison chip (U2), the other end of resistor R12 is connected to one end of resistor R11 and The pin 5 of the first voltage comparison chip (U2) is connected, the other end of the resistor R11 is connected with one end of the resistor R13 and the pin 9 of the first voltage comparison chip (U2), the other end of the resistor R13 is connected to the ground, and the other end of the resistor R7 One end is connected to pin 6 of the first voltage comparison chip (U2) and one end of resistor R4, the other end of resistor R4 is connected to the anode of diode D3, and the cathode of diode D3 is connected to pin 1 of the first voltage comparison chip (U2), resistor One end of R5 is connected to one end of resistor R6, the other end of resistor R5 is connected to +15V voltage, the other end of resistor R6 is connected to the positive pole of diode D5 and the negative pole of diode D4, and the connection point (S1) is connected to the microcontroller module (1) The first pin (P1.0) of the third input and output I/O is connected; the other end of the resistor R9 is connected to the pin 4 of the first voltage comparison chip (U2) and one end of the resistor R15, and the other end of the resistor R15 is connected to The anode of diode D6 is connected, the cathode of diode D6 is connected with pin 2 of the first voltage comparison chip (U2), one end of resistor R16 and one end of resistor R17, the other end of resistor R16 is connected to +15V voltage, the other end of resistor R17 It is connected with the anode of the diode D7 and the cathode of the diode D8, and the connection point (S2) is connected with the second pin (P1.1) of the third input and output I/O of the microcontroller module (1); the other end of the resistor R14 is connected with the Pin 8 of the first voltage comparison chip (U2) is connected to one end of resistor R10, the other end of resistor R10 is connected to the anode of diode D9, and the cathode of diode D9 is connected to pin 14 of the first voltage comparison chip (U2) and resistor R18. One end is connected to one end of resistor R19, the other end of resistor R18 is connected to +15V voltage, the other end of resistor R19 is connected to the positive pole of diode D10 and the negative pole of diode D11, the connection point (S 3) Connect to the third pin (P1.2) of the third input and output I/O of the microcontroller module (1); connect pins 3 and 12 of the first voltage comparison chip (U2) to +15V and -15V voltages respectively ; The above-mentioned cosine signal interval discrimination circuit includes a second operational amplifier chip (U1'), a second voltage comparison chip (U2') and corresponding peripheral components; pin 2 of the second operational amplifier chip (U1') is connected to resistor R1', Resistor R2' and one end of resistor R101' are connected together, pin 3 of the second operational amplifier chip (U1') is connected to one end of resistor R3', the other end of resistor R3' is connected to one end of capacitor C1' and grounded, capacitor C1 The other end of 'is connected to the other end of the resistor R1', which is the signal input end of the cosine signal interval discrimination circuit; the other end of the resistor R101' is connected to the DC bias voltage VB, and the other end of the resistor R2' is connected to the second operational amplifier Pin 1 of the chip (U1'), the anode of the diode D1', the cathode of the diode D2', one end of the resistor R7', one end of the resistor R14' and one end of the resistor R9' are connected together, and the 4 pins of the second operational amplifier chip (U1') , Pin 11 are respectively connected to +15V, -15V voltage, the cathode of the diode D1' is connected to one end of the resistor R8' and the DC voltage VCC, the anode of the diode D2' is connected to the ground, and the other end of the resistor R8' is connected to the resistor R12'. One end is connected to pin 7 of the second voltage comparison chip (U2'), the other end of resistor R12' is connected to one end of resistor R11' and pin 5 of the second voltage comparison chip (U2'), and the other end of resistor R11' is connected to pin 5 of the second voltage comparison chip (U2'). One end of resistor R13' is connected to pin 9 of the second voltage comparison chip (U2'), the other end of resistor R13' is connected to ground, and the other end of resistor R7' is connected to pin 6 of the second voltage comparison chip (U2') and One end of the resistor R4' is connected, the other end of the resistor R4' is connected to the positive pole of the diode D3', the negative pole of the diode D3' is connected to pin 1 of the second voltage comparison chip (U2'), one end of the resistor R5' and the pin of the resistor R6' One end is connected, the other end of resistor R5' is connected to +15V voltage, the other end of resistor R6' is connected to the positive pole of diode D5' and the negative pole of diode D4', the connection point (S1') is connected to the first The first pin (P1.5) of the four-input/output I/O is connected; the other end of the resistor R9' is connected to the pin 4 of the second voltage comparison chip (U2') and one end of the resistor R15', and the other end of the resistor R15' One end is connected to the anode of diode D6', the cathode of diode D6' is connected to pin 2 of the second voltage comparison chip (U2'), one end of resistor R16' and one end of resistor R17', and the other end of resistor R16' is connected to + 15V voltage, the other end of the resistor R17' is connected to the anode of the diode D7' and the cathode of the diode D8', and the connection point (S2') is connected to the second pin ( P1.4) is connected; the other end of the resistor R14' is connected to the 8-pin of the second voltage comparison chip (U2') and one end of the resistor R10', and the other end of the resistor R10' is connected to the anode of the diode D9', and the diode D9' The negative pole of the second voltage comparison chip (U2') pin 14, resistor R18' One end is connected to one end of resistor R19', the other end of resistor R18' is connected to +15V voltage, the other end of resistor R19' is connected to the positive pole of diode D10' and the negative pole of diode D11', the connection point (S3') is connected to the microcontroller The third pin (P1.3) of the fourth input and output I/O of the module (1) is connected; the 3rd and 12th pins of the second voltage comparison chip (U2') are respectively connected to +15V and -15V voltages.