JP2007114090A - Resolver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive sensor that can simultaneously and coaxially detect displacement in the rotating direction and displacement in the axial direction. <P>SOLUTION: A VR resolver, of a single-phase excitation and two-phase output type, is equipped with a resolver stator 102 and a resolver rotor 101, made by coaxially superimposing two or more similar rotor cores that are different in scale with their angles being uniformized. This VR resolver detects a position in the axial direction by finding the transformation ratio in respective layers from an resolver output of the resolver stator 102, while detecting the angle information in the rotating direction by a tracking converter, irrespective of the voltage transformation ratios. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resolver that can detect a rotational displacement and an axial displacement simultaneously on the same axis.

  Servo actuators used in FA devices include a rotary servo motor and a linear motion type linear servo, which are used properly depending on the configuration of the device used. An encoder or resolver is used as a position sensor for a rotary servo motor, and a linear scale or LVDT is used for a linear motion linear motor.

  Here, the configuration of a conventional VR resolver that detects a positional displacement in the rotational direction will be described with reference to FIG. The VR resolver is composed of a resolver rotor 401 and a resolver stator 402, and the resolver rotor is provided with salient poles for the excitation signal input to the primary winding. In this conventional example, three salient poles are provided. Since the output winding has two phases, when the resolver rotor makes one rotation, three cycles of sin and cos signals are generated.

  Next, a conventional resolver conversion circuit will be described with reference to FIG. A resolver / digital conversion circuit based on a tracking method is generally used. As shown in FIG. 2, a sine wave excitation signal Asinωt having a constant frequency and a constant amplitude A is output from the excitation circuit 212 to the resolver 201 and the demodulator 207. The resolver 201 outputs KA sin θ · sin ωt and KA cos θ · sin ωt corresponding to the transformer transformation ratio of the resolver and the rotor angle θ of the resolver, and is amplified by the amplifiers 202 and 203.

  Here, K is a transformation ratio of the resolver. The sin φ generated inside the converter is multiplied by KA sin θ · sin ωt by the multiplier 204, and cos φ is multiplied by KA cos θ · sin ωt by the multiplier 205, and subtraction is performed by the subtracter 206, whereby KA sin (θ−φ) · sin ωt is obtained. Then, sin ωt, which is an excitation component, is removed by the demodulator 207, and the harmonic component is removed by passing through the low-pass filter 208 to generate θ−φ.

  The θ-φ is input to the voltage controlled oscillator 209, and the voltage controlled oscillator 209 generates a pulse corresponding to the input voltage, and the pulse is input to the UP / DOWN counter 210. A kind of PLL servo loop is constructed in which sin φ and cos φ are generated by referring to the SIN and COS table 211 whose address is the counter value of the counter 210, and the sin φ and cos φ are hooded back to the multipliers 204 and 205. Then, by operating θ−φ toward 0, the angle data φ can be obtained when θ−φ = 0 (see, for example, Patent Document 1).

On the other hand, depending on the device, for example, when it is necessary to move the workpiece to a certain position and further arrange the workpiece by controlling the angle, operations of a rotating system and a linear motion system are required. Conventionally, a rotary servo motor and a direct-acting linear servo are combined, but the combination mechanism uses ball screws, belts, pulleys, etc., which increases the device configuration and costs. Will also be high. In general, the use of a linear scale further increases the cost.
JP-A-63-71618

  The problem to be solved is that there is no sensor that can detect the displacement in the rotational direction and the displacement in the axial direction simultaneously on the same axis. That is, when an actuator is configured by integrating a rotating system and a linear motion system on the same axis, both are used in combination to detect the positional change in the rotational direction and the axial direction at the same time. An encoder or resolver is used, and a linear scale or LVDT is used to detect the position of the linear motion system. However, when the configuration is large, the cost is high, and there is little merit of integrating.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an inexpensive sensor that can simultaneously detect a displacement in a rotational direction and a displacement in an axial direction on the same axis.

  In order to solve the above problems, the present invention provides an output of a VR resolver of a one-phase excitation and two-phase output type having a resolver rotor in which two or more rotor cores of different scales are aligned in the axial direction at the same angle. The displacement in the rotation direction and the displacement in the axial direction are detected simultaneously.

  According to the present invention, the rotational system and the linear motion position sensor can be integrally configured, and the coaxial rotational direction and axial displacement can be detected simultaneously. For this reason, the structure of the actuator which integrally comprises a rotating system and a linear motion system on the same axis | shaft can be simplified.

  Two or more similar rotor cores of different scales are amplitude-modulated from sin-phase excitation 2-phase output type VR resolver output having a resolver rotor in which the angles are aligned in the axial direction to sin θ corresponding to the rotation angle θ. A third multiplier for multiplying the resolver output signal by sin φ generated in the conversion circuit; a fourth multiplier for multiplying cos θ by amplitude-modulated resolver output signal by cos φ generated in the conversion circuit; An adder for adding the operation results of the fourth multiplier, a third demodulator, a second demodulator for removing the excitation signal component from the signal calculated by the adder, and a second demodulator And a resolver transformation ratio detecting means comprising a divider for removing the amplitude component of the excitation signal from the signal output from the demodulator, and calculating the resolver transformation ratio to determine the resolver axial ratio from the transformation ratio information. The displacement in the rotation direction is obtained and the displacement in the rotational direction is detected by the tracking converter as in the conventional case.

  The resolver according to the first embodiment is a one-phase excitation two-phase output type VR resolver. In order to detect the position in the rotational direction and the axial direction on the same axis, the resolver rotor is a similar rotor core having two or more different scales. Are stacked in the axial direction at the same angle. The position in the rotational direction is detected from the resolver output by the tracking converter, and the displacement (position) in the axial direction is detected by obtaining the transformation ratio of each layer.

  In FIG. 1, a VR resolver rotor 101 and a stator 102 with one-phase excitation and two-phase output are configured, and the rotor 101 is configured by matching the angles with three-stage similar scale differences. This resolver is an example of a shaft angle multiplier of 3X.

On the other hand, in FIG. 2, the excitation signal Asinωt having a constant frequency and constant amplitude is input from the excitation circuit 112 to obtain the output signals sinθ · sinωt and cosθ · sinωt from the resolver 101, and the output signals are converted into respective output signals inside the conversion circuit. The cos φ and sin φ generated from the generated angle φ are converted into KA (sin θ · cos φ−cos θ · sin φ) · sin ωt and KA (sin θ · sin by the multipliers 104 and 105 and the multipliers 114 and 115, respectively.
φ + cos θ · cos φ) · sin ωt is calculated.

  The signal output from the demodulator 107 that removes the excitation signal component from the signal KA (sin θ · cos φ−cos θ · sin φ) · sin ωt, the low-pass filter 108 that removes the harmonic component of the output signal from the demodulator 107, and the signal output from the low-pass filter 108 Refer to voltage controlled oscillator 109 that generates proportional pulses, UP / DOWN counter 110 that counts pulses output from voltage controlled oscillator 109, and sinφ and cosφ that are addressed by the count data of the UP / DOWN counter. SIN, COS table 111, demodulator 117 for removing excitation signal components from signals KA (sin θ · sin φ + cos θ · cos φ) · sin ωt, and divider 118 for dividing the amplitude value of the excitation signal from KA output from the demodulator. Is done.

  Resolver transformation ratio information output from the divider 118 is output to the CPU 113, and is used as a control signal for gain adjustment of the excitation amplifier in the resolver excitation circuit 112 after arithmetic processing by the CPU 113. Also, the resolver transformation ratio information is stored in the non-volatile storage means 119 via the CPU 113, and the resolver transformation ratio information is saved when the system is installed, for example, a servo amplifier, and from the next startup. The axial displacement of the resolver rotor can be obtained using this transformation ratio information.

  Here, the relationship between the amplitude of the resolver output signal, that is, the transformation ratio, and the position information is shown in FIG. In FIG. 3, when the axial position of the resolver rotor is Z1, the amplitude of the resolver output signal is A1, the transformation ratio is obtained from the amplitude of A1 and excitation voltage information, and the transformation ratio and position stored in advance by the nonvolatile storage means 219. The axial position is determined by the correlation data with the information. The position data can be determined similarly for the amplitudes A2 and A3. Regarding the rotation direction, angle information can be obtained by a conventional tracking converter regardless of the transformation ratio.

  The resolver of the present invention is useful for an actuator that needs to detect displacement in the rotational direction and the axial direction on the same axis at the same time.

Configuration diagram of a VR resolver in Embodiment 1 of the present invention 1 is a block diagram of a resolver / digital conversion circuit according to a first embodiment of the present invention. Explanatory drawing of the axial displacement and resolver output (amplitude) of the resolver rotor of the present invention Configuration diagram of a conventional VR resolver Block diagram of a conventional resolver / digital conversion circuit

Explanation of symbols

101, 401 Resolver rotor 102, 402 Resolver stator 201, 501 Resolver 202, 502 First amplifier 203, 503 Second amplifier 204, 504 First multiplier 205, 505 Second multiplier 206, 506 Subtractor 207 , 507 First demodulator 208, 508 Low-pass filter 209, 509 Voltage controlled oscillator 210, 510 UP / DOWN counter 211, 511 SIN, COS table 212, 512 Excitation circuit 213, 513 CPU
214 Third multiplier 215 Fourth multiplier 216 Adder 217 Second demodulator 218 Divider 219 Nonvolatile storage means

Claims (5)

A resolver characterized by simultaneously detecting a displacement in a rotational direction and a displacement in an axial direction on the same axis by a resolver rotor having a single configuration. 2. The resolver according to claim 1, wherein the resolver rotor is a one-phase excitation two-phase output type VR resolver in which two or more rotor cores having different scales are aligned in the axial direction at the same angle. A resolver / digital conversion circuit characterized in that a displacement in the axial direction of the resolver is obtained by calculation from the amplitude of the resolver output signal according to claim 2. An excitation circuit for inputting an excitation signal Asin ωt having an amplitude A to a resolver according to claim 2 as a means for detecting an amplitude of a resolver signal for obtaining a displacement in an axial direction, and a resolver according to claim 2, and the resolver A first multiplier that multiplies cosφ generated inside the conversion circuit to KAsinθ · sinωt, which is a resolver output signal that is amplitude-modulated to sinθ corresponding to the rotation angle θ, and the other that corresponds to the rotation angle θ of the resolver. A second multiplier that multiplies the output signal KAcosθ · sinωt by sinφ generated inside the conversion circuit, a subtractor that divides the operation results of the first and second multipliers, and the first and second A demodulator that removes the excitation signal component from the computation results computed by the multiplier and subtractor, and a low-pass that removes the harmonic component from the signal output from the demodulator A tracking device including a filter, a voltage-controlled oscillator that outputs a pulse using the signal that has passed through the low-pass filter as an input signal, a counter that counts the output pulse of the voltage-controlled oscillator, and a sin and cos reference ROM that has a counter value as an address. In the resolver / digital conversion circuit of the system, a third multiplier that multiplies sin φ generated in the conversion circuit by a resolver output signal that is amplitude-modulated to sin θ corresponding to the rotation angle θ output from the resolver, and amplitude of cos θ A fourth multiplier that multiplies the modulated resolver output signal by cosφ generated in the conversion circuit; an adder that adds the operation results of the third and fourth multipliers; and third and fourth multipliers A second demodulator that removes the excitation signal component from the signal calculated by the adder, and an excitation signal from the signal output from the second demodulator. A resolver / digital conversion circuit comprising a resolver transformation ratio detection means comprising a divider for removing the amplitude component of the resolver, determining the transformation ratio of the resolver, and detecting the axial displacement of the resolver based on the transformation ratio information . An actuator equipped with the resolver according to claim 1.

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