SU922847A1 - Shaft angular position-to-code converter - Google Patents

Description

The invention relates to the field of automation and computing and can be used to communicate analog information sources with a digital computing device. ' ³

Known converters of the angle of rotation of the shaft into the code, which contain sine-cosine sensor (ACS) outputs: through the switch of octants- ^{10, they are} connected to a functional converter that implements the tangent dependence (12,

The disadvantage of such converters is low accuracy. ¹⁵

Converters are also known in which the ACS is connected via a switch of squares to series-connected blocks for the formation of bits of the output code. Each block consists of an adder, a subtractor, analog keys and a comparator. Formation of bits of the pro2 code

can be obtained by solving trigonometric identities [2].

The disadvantage of this device is its complexity.

The closest to the proposed technical solution is a shaft angle converter into a code containing a sine-cosine rotating transformer, the output of which is connected to the octant switch, one output of the octant switch connected to one input of the comparison element and through the first scaling element to one input of the first adder another output through the second scaling element is connected to another input of the first adder, the output of which is connected to the reference input of the code to voltage conversion unit digital inputs of which are connected to the outputs of the register, and the output is connected to another input of the comparison element, the output of the comparison element is connected to

3 922847 4

the other input of the comparison element, is the voltage, the output of which is connected to

the output of the comparison element is connected to the control inputs of the register and block. control octant switch, clock generator. connected to $ octact switch and register control unit, register output is connected to one input of another adder and a correction code driver, the outputs of which are connected to other inputs of the second adder · [3 3.

The disadvantage of this device is low accuracy in the absence of a shaper corrective, 5 code. With the introduction of the correction code driver, the device becomes more complex.

The purpose of the invention is to improve the accuracy of the converter. ₂ o

This goal is achieved by

that in the converter of the angle of rotation of the shaft into a code containing a sine-cosine rotary transformer, the outputs of which are connected to the locator switch octants, one output of the switch octants is connected to one input of the comparison element and the first scaling element and the other output through the second scaling ₃₀ element to one input of the adder, the output of which is connected to the reference input of the code-to-voltage conversion unit, whose digital inputs are connected to the outputs of the register, and the output is connected to another input of the ele cient comparison output _{element> w} comparison ment connected to the control inputs of the register and the switch control unit octants, with a shape tors, θ ₄ bars connected to the control unit and pereklyuchatelem.oktantov register, the second adder having introduced the second and third blocks in the code conversion voltage and tre- * Tille scaling element, the digital inputs of the second and third code conversion units into a voltage connected to the register output, the reference input of the third code into a voltage conversion unit ⁵⁰ is connected to

the second output of the switch octants, and the output through the third scaling element is connected to one input of the second adder, another input of the second adder is connected to the output ^{55 of the} first scaling element, and the output is connected to the reference input of the second code conversion unit

the other input of the first adder.

The essence of converting the angle of rotation of the shaft into a digital code consists in forming voltages proportional to the sine and cosine of the angle, determining the three most significant bits of the code, i.e. determining the octant number of the angle to be converted within the selected octant, balancing the stresses in accordance with the following relation

where Ts51p <A and izob- voltage,

proportional to the sine and cosine of the angle a. shaft turning;

N - code value within one octant ;.

K _and , K ^, - scale factors.

The coefficients K _and K K 3 are chosen so that in the whole range of angles within one octant angle <A. and the corresponding numerical value of the N code were equal to each other with high accuracy. For example, when the values of the coefficients: K ^ = = 0.7854031; K _g = 0.24779391 K _e = _; = 0.0331970, equality (3) is provided with an error of no more than 0.00065%, which corresponds to the equality of the angles c and the corresponding code N with an error of no more than 1 arc second.

The drawing shows a block diagram of the device.

The converter contains a sine-cosine rotary transformer (SCWT) 1, the excitation winding of which is recorded from source 2, and the outputs of the sine and cosine windings are connected to the inputs of the switch 3 octants. The first output of the switch 3 octants is connected to the first input of the comparison element 4 and through scaling element 5 - with the first input of the adder 6. The second output of the switch of 3 octants is connected to the reference input of the code-to-voltage conversion unit 7 and through the scaling element 8 - to the first input of the adder 9. The output of the block 7 is connected through the scaling element 10 to the second input of the adder 6, you 5 922847 6

the stroke of which is connected to the reference input of the voltage code conversion unit. The output of the block 11 is connected to the second input of the adder 9, the output of which is connected to the reference input of the block 5 of the code-to-voltage conversion. The output of the block 12 is connected to the second input of the comparison element 4, the output of which is connected to the control input of the register 13 for controlling blocks 7.11 and 12 and to the input of the block 14 for controlling the octant switch.

The outputs of the register 13 are connected to the control inputs of blocks 7, 11, 12 and to the output buses of the converter. 15

The control output of the octant switch control unit 14 is connected to the input of the octant switch, and the code outputs of the block 14 are connected to the output buses of the converter * 20. “.

Synchronization inputs of the block 14 and the register 13 is connected to the outputs of the driver 15 cycles.

Angle converter works 25

in the following way.

At the outputs of the ACS 1, direct and inverse voltages are formed, proportional to the sine and cosine of the angle of rotation of the shaft. These voltage ₃₀ supplied to the switch Nia octants 3, at the first output of which is formed by ^p modulo minimal stress, on the other. - more.

The converter operates according to the cycles generated by the driver 15. In the first three cycles, the three most significant bits of the output code are formed and the voltage is switched on the switch ^ · le 3. Starting from the fourth cycle, the conversion is performed by the bitwise balancing of the voltage-, acting on the first input of the comparison element 4 , the voltage connected to the second input of the element 4. Balancing is performed in the range of 45 - degree segment.

If the value of the angle to be converted is in the first octant, then voltage 1 / ^ ίη A is applied to the first input of element 4, and

where N is the code value in register 13, each of blocks 7,11,12 implements

the function of multiplying the voltage applied to its reference input by the value of the code Ν applied to its digital input. Therefore, the degree of code N at the outputs of series-connected blocks 7, 11 and 12 gradually increases.

At the moment of equality of the voltages at the inputs of element 4 (with the values of the scale factors K ^, K ^, K ^, indicated above), the value of the N code with high accuracy corresponds to the value of the angle A of the shaft rotation,

The three high-order bits of the converter's output code are removed from the code buses of the octant switch control unit 14, and the low-order bits are removed from the outputs of register 13. In this case, the odd octants of register 13 are removed, and the direct code is removed, and the even one.

The methodical error of the conversion of the proposed device does not exceed 1 arc-second, which is several dozen times less than in the known.

Thus, the proposed converter has a significantly higher conversion accuracy than what is known.

Claims (1)

Claim A shaft rotation angle converter into a code containing a sine-cosine rotary transformer whose outputs are connected to an octant switch, one output of the octant switch is connected to one input of the reference element and the first scaling element and connected to one input of the first adder, the output of which is connected to the reference input of the code-to-voltage conversion unit, the digital inputs of which are connected to the outputs of the register, and the output connected to another input of the ele cient comparison> yield comparison element is connected to the control inputs of the register and the switch control block octane. com, the clock maker connected to the control unit of the octant switch and the register, the second adder, which is designed to increase the accuracy of the converter, 7 The second and third code-to-voltage conversion blocks and the third scaling element are entered into it, the digital inputs of the second and third code-to-voltage conversion blocks are connected to the register outputs, the reference input of the third code-to-voltage conversion block is connected to ·. the second output of the octant switch, and the output through the third scaling element is connected to one input 'of the second adder, the other input of the second adder is connected to the output of the first scaling element, and the output is 922847 eight keys to the reference input of the second block conversion code into a voltage, the output of which is connected to another input of the first adder.