JPH02299500A - Position controller - Google Patents

Abstract

PURPOSE:To enable optimal control by detecting relative position between a mover and a stator through a position detector then performing control based on the detected position. CONSTITUTION:A driving means 1 is mainly composed of a rotor 2 and a stator 3, where the rotor is driven by exciting coils 3a, 3b of the stator 3. A position detecting means 5a is coupled directly with the rotor 2 and the output from the position detecting means 5a is fed through a digital positional signal producing means 5b to a comparing means 7, then the difference from a position input signal 7a is fed to an electrical angle operating means 8 in order to operate a corresponding electrical angle. A function generating means 9 produces a two-phase sinusoidal signal corresponding to the operating amount of the driving means 1, according to the electrical angle. Since feedback closed loop control is employed, control accuracy is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a position control device, and more particularly to a position control device capable of high-speed and highly accurate positioning.

2. Description of the Related Art In recent years, the performance of information equipment has improved dramatically, and as a result, faster and more accurate position control devices are required as driving means for magnetic disk drives, printers, and the like.

Conventionally, stepping motors have been widely used as driving means for these devices mentioned above.

Hereinafter, a conventional position control device will be explained with reference to the drawings. FIG. 13 is a block diagram showing the principle of a stepping motor, which is most widely used as a driving means for conventional position control devices.

FIGS. 13(a) and (b) are hybrid P
M type (Hybrid Permanent Magne
FIG. 2 shows a cross-sectional view and a perspective view of a stepping motor called "T Type". 131 is a rotor, which is composed of a magnet 140 magnetized in the axial direction and magnetic bodies 141 and 142 in which the magnets are laminated from both sides, and magnetic pole teeth 135 and 136 carved at a constant pitch on the circumference of the magnetic body. It is equipped with On the other hand, 132 is a stator, which is composed of a magnetic core having a magnetic pole tooth group 137 on the opposite surface of the rotor 131, and a plurality of coils 133a, 133b and 134a, 134b wound around the magnetic core. . 143 is a rotation axis. A plurality of coils 133a and 133b and 1
34a and 134b are each connected in series.

FIG. 14 is a basic drive circuit diagram for driving the hybrid PM type stepping motor shown in FIG. 13. Switch 112a, L12b.

Coils 133a and 133b are connected to the midpoint of the bridge circuit composed of 113a and 113b, and the switch 11
Coils 134a and 134b are connected to the intermediate point of the bridge circuit composed of 4a, 114b, 115a, and 115b. Here, for example, switches 112, 114, 1
By sequentially opening and closing coils 13 and 115, the plurality of coils 133 and 134 are excited from the outside in order, and the rotor 141 changes its position and advances depending on the state of excitation of the coils 133 and 134. These switches are usually constructed of semiconductors.

FIG. 15 is a diagram showing the rotation angle-torque characteristics of the stepping motor shown in FIG.
3a and 133b by closing the switch 112 in FIG.
This shows the rotation angle-torque characteristics when electricity is applied in the direction from 12a to 112b.In this excited state, the rotor has a position holding characteristic where it stands still at the 0 point.Switches 112゜114, 113, 115 are synchronized with external signals. If the steps are sequentially opened and closed, the rotation angle-torque characteristic of the stepping motor is 121°12
2.123, 124, it can be seen that the rotor rotates (walking) by 1/4 tooth pitch (906 in electrical angle) in synchronization with the external signal. ).

FIG. 16 is a fundamental configuration diagram of a conventional position control device configured using a stepping motor as such a driving means. In FIG. 16, 151 is a step pulse input, 152 is a moving direction command input, 153 is a sequential pulse control circuit, 154 is a bridge circuit, 155 is a stepping motor, and 156 is a position control object. Such a position control device is called an open-loop positioning system, and by sequentially operating the bridge circuit 154 by inputting step pulses to the sequential pulse control circuit 153 and stepping the rotor of the stepping motor 155, the controlled object 156 is controlled. It was made movable (e.g. high rail:
"Latest trends in floppy devices and controller design technology" J
, Interface, MAY, 1983, P, 150~
P, 2(16)).

Since such a conventional position control device that utilizes a stepping motor as its driving means is an open-loop positioning system, it is characterized in that the electronic control circuit portion is relatively simple. That is, since positioning can be performed by sending pulses, it can be easily constructed by applying pulses directly from the microprocessor to the power supply circuit. Also, other drive means such as voice coil motor, D
C.

Another feature is that it has higher power efficiency than AC servo motors. This is because actuators such as stepping motors, which have uneven magnetic pole teeth in the magnetic circuit, have good magnetic efficiency (and a very large thrust (torque) even with a small current.As a result, they are small, compact, and energy efficient. It had the characteristic of being.

However, on the other hand, there are problems in terms of high speed and high accuracy. For example, when a stepping motor serving as a driving means is positioned and stopped, there is a phenomenon in which the stepping motor vibrates around the stopping point.

In other words, it takes time to settle.

FIG. 17 is a diagram showing a phenomenon in which a conventional oven loop position control device using a stepping motor as a driving means vibrates around a stop point. In order to reduce this vibration and shorten the settling time, mechanical viscous resistance may be applied to the movable part and the mover. However, the structure becomes complicated and high-speed operation is hindered by this viscous resistance.

This is a drawback that position control devices that utilize voice coil motors, DC and AC servo motors do not have. Furthermore, since stepping motors can obtain speeds synchronized with external pulse signals, it seems that in order to move the controlled object at high speeds, it is sufficient to increase the frequency of the pulse signals, but this is not true at low speeds when the thrust is large. Differently, during high-speed driving, due to the time constant of the coil and the influence of iron loss,
The rise of the current is delayed and torque cannot be generated efficiently, and if the frequency of the pulse signal is made too high, step-out is likely to occur.

Furthermore, by making the magnetic pole teeth of the rotor and stator finer and increasing their number, it is possible to reduce one step angle and increase the resolution of position control of the controlled object, but in reality, there is a limit to the mechanical accuracy. However, because the switching frequency of the current in each coil increases, the efficiency decreases rapidly. General electronic publishing company,
P-15 to P, 42) Furthermore, in order to increase the resolution of position control, the magnetic pole teeth of the rotor and stator are made finer, the number of them is increased, and the one step angle is reduced. There is a tendency for the self-retention force against impact force to become smaller.

Problems to be Solved by the Invention As mentioned above, conventional open-loop position control devices that use a stepping motor as a drive means are difficult to increase speed due to step-out, etc., are prone to vibration, and have a long settling time for positioning. It had a drawback. Furthermore, it is structurally difficult to increase the positioning resolution. Furthermore, even if the resolution was increased, there was a drawback that the stiffness decreased.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a position control device that is capable of high-speed, high-resolution, and high-stiffness positioning that could not be achieved with conventional stepping motors.

Means for Solving the Problems In order to solve the above-mentioned vIAB, the position control device of the present invention includes a drive means that includes a movable element and a stator that can move the movable element by applying a relative motion force to the movable element. and position detecting means for outputting alternating signals of multiple phases having mutually different phases in accordance with the relative movement of the movable element and the stator. In order to digitally generate relative position information, carrier signal generating means generates a carrier signal modulated by the alternating signals of a plurality of phases having different phases, and demodulates phase information of the modulated carrier signal. a digital position information generating means including a digital sample holder means for controlling the drive means based on a deviation between the relative position information between the movable element and the stator and a position input signal from the outside; The apparatus is configured to include a digital calculation means for calculating a quantity, and a biasing means for biasing the drive means based on the manipulated variable.

Function The position control device of the present invention has the following functions due to the above-mentioned configuration. First, the relative position of the movable element and the stator of the driving means is detected by the position detecting means, and the position detecting means detects the relative position of the movable element and the stator. , the relative position information between the stators is digitally generated with high resolution, the deviation between this and the position input signal from the outside is determined, and based on this, the operating amount for the drive means is optimized by the digital calculation means. By controlling the speed, the torque of the driving means can be generated efficiently at all times, and the controlled object can be moved at high speed without causing step-out. Furthermore, at the same time, the position control target can be quickly (settled) at the target position while vibrations are suppressed.Also, high-resolution positioning control can be performed using the position detection means and digital position information generation means.Furthermore, the digital calculation means , it is possible to easily obtain higher stiffness than before.

Embodiment Hereinafter, a position control device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a position control device in one embodiment of the present invention. FIG. 1 shows an embodiment in which a rotary actuator such as a stepping motor is used as the driving means. In Figure 1, 2 is the rotor (mover)
and the tooth-shaped unevenness made of the permanent magnet 2a and the magnetic material<r
tt1 pole tooth) 2b. Coils 3a and 3b are wound around a magnetic core, and together with the magnetic core, constitute a stator 3 that faces the rotor 2 with a predetermined gap in between. A driving means 1 is constructed using the rotor 2 and stator 3 as main elements. 4 is a position control target. 5a
detects the position of the rotor 2 or the position control target, and generates two-phase sinusoidal alternating position signals sa, s with a phase shift of 90°.
This is a position detection means that outputs b. 5b is a digital position signal generating means which inputs the two-phase sinusoidal alternating signals sa and sb output from the position detecting means 5a, and digitally outputs the position signal S of the rotor 2 with high resolution. This position signal is a signal that linearly displays the absolute position of the movable range of the controlled object with high resolution using a certain reference point as the origin. Reference numeral 7 denotes a comparison means, which inputs the position signal S of the rotor 2 and the position input signal a applied to the position input terminal 7a from the outside, and outputs a deviation signal c (=ab).

Reference numeral 8 denotes an electrical angle calculation means which inputs the deviation signal C, performs appropriate control calculations, and outputs an electrical angle amount e. Reference numeral 9 denotes a function generating means, which outputs two-phase sine wave signals sc and ss corresponding to the operation amount to the drive means 1, according to the electrical angle amount e. 6 is a digital calculation means including the above 7.8.9. 10 is a biasing means, and a function generating means 9
The two-phase sine wave signals sc and ss of the manipulated variables outputted from the drive means 1 are amplified to energize the coils 3a and 3b of the driving means 1 with current, respectively.

FIGS. 2A and 2C are block diagrams of an embodiment of the digital position signal generating means 5b of FIG. 1 of the present invention. First, in FIG. 2(a), lla.

11b is the signal output from the position signal detection means 5a, the phase of which is 90
This is a position signal amplifier that amplifies two-phase sinusoidal alternating position signals sa and sb that are shifted by degrees. 12a, 12b
is a modulation means which generates high frequency carrier signals 16a, 1 with the two-phase sine wave outputs of the position signal amplifiers 11a, llb.
6b, respectively. Reference numeral 14a is a carrier signal generating means, which divides the reference clock signal of the oscillator 14b, which is a reference clock generating means, into (1
/ n frequency division) to create carrier signals 16a and 16b. These two carrier signals 16a.

16b are out of phase with each other by 90 degrees, and are connected to the carrier signal generating means 14a to the modulating means 12a.

12b. 13a is a synthesizing means, which is an adding circuit for adding together the modulated outputs of the two modulating means 12a and 12b. 13b is a low-pass filter means that cuts off harmonic components of the modulated outputs added by the adder circuit 13a and extracts only the fundamental wave component. 13c is a sample-and-hold pulse signal forming circuit which converts the fundamental wave into a rectangular wave and then forms a sample-and-hold pulse U. 15a.

Reference numerals 15b denote a digital counter means for demodulating the phase information contained in the rectangular wave of the fundamental wave, and a temporary holding means for sample and hold.

Digital counter means 15a counts the reference clock signal and generates digital harmonics.

The temporary holding means 15b is a temporary storage circuit such as a memory, a register, or a latch circuit, and samples and holds the count contents of the digital counter means 15a using the sample and hold pulse signal U. 17
is a digital sample holder means, and the above 1
3c, 15a.

The digital counter means 15a, which consists of 15b and 14b and has the function of demodulating the phase information contained in the rectangular wave of the fundamental wave, counts the above-mentioned reference clock signal. - The sample hold means 17 demodulates the phase information included in the rectangular wave of the fundamental wave, thereby detecting the position signal detecting means 5a.
It is possible to digitally divide (interpolate) into n within the range of one period pitch of the two-phase sinusoidal alternating position signals sa and sb with a phase shift of 90 degrees, which are output by the
The phase discrimination ability is only within the range of one cycle pitch of sa and sb. In order to enable length measurement within a wider range, a reversible counter means 18a is provided to count the number of times the alternating position signal exceeds one cycle pitch. 18b is a reversible count pulse generation circuit, and the content of the temporary holding means 15a changes from 0 (a value close to) to n (a value close to);
Every time there is a sudden jump from (value close to) to (value close to)
Generate up count pulses and down count pulses, respectively. The reversible counter means 18a receives the up count pulse and down count pulse and counts up or down. 18c is an origin/initial reset signal input terminal to the reversible counter means 18a. A position register 19 combines the contents of the reversible counter means 18a and the contents of the temporary holding means 15b as an upper bit part and a lower bit part, respectively. Reference numeral 20 denotes an output terminal of this position register 19, which is the output of the digital position signal generating means 5b (this is the position signal of the rotor 2).

Here, the principle of this digital position signal generating means 5b will be explained. Now position signal amplifier 11a.

sa and sb of the two-phase sine wave output of 11b are respectively
θ), EB(θ), and can be expressed as follows.

EB(θ)=E-CO3(2 to θ/θp)”...=
(la)EA(θ)=E-3IN(2πθ/θ,)...
(1b) where θ is the rotation angle (position) of the rotor 2, θ2 is the one-period pitch of the sinusoidal alternating position signal output by the position signal detection means 5a, and E is the wave of the sinusoidal position signal. It's expensive. Here, on the other hand, carrier signals 16a, 1
If 6b is respectively cA(t) and CB(t), it can be expressed as follows.

CA(θ)=CO5(2tt r c t ) −
-(2a) CB(θ)=SIN (2πfct)
(2b) However, fc is the carrier frequency.

If the result of modulation by the modulation means 12a and 12b and addition by the adding circuit is p (t, θ), then the following equation is obtained. This means that the carrier with frequency fc is 2πθ/
This means that a phase term θp is included.

In other words, position information is converted into phase information at p (t, θ). Therefore P (t,
The position of the rotor 2 can be recognized by demodulating the phase information of θ). In addition, in order to accurately detect the rotor position from the above p (t, θ), the position signal EA (θ) is
, EB(θ) must be sinusoidal with little distortion with respect to the rotational position θ. If the distortion is large, the linearity will deteriorate and the low-pass filter means 13b should be
, θ). This is because the actual carrier signals 16a and 16b are generally rectangular waves containing many harmonics. Next, it is necessary to demodulate the modulated and added signal P(t, θ) to separate and extract only the phase information 2πθ/θ.6 In the embodiment of the present invention, the signal P(t, θ) for the carrier signal is
θ) using digital sample holder means 17.
to demodulate. In this demodulation method, first, the digital counter means 15a counts the reference clock signal to create digital harmonics, forms a sample-and-hold pulse U from the signal P(t, θ), and uses this pulse U to count the reference clock signal. This is a simple method of sampling and holding the harmonics of the means 15a. Specifically, the count contents of the digital counter means 15a are transferred to the temporary holding means 15b using a sample hold pulse U.

The sample-and-hold pulse U is generated from the rising (or falling) edge of a rectangular wave by shaping the signal p (t, θ). With this configuration, the phase information (2
πθ/θ, ) is digitally taken into the temporary holding means 15b. The frequency of the carrier signal is fc, and if the reference clock signal n-fc, which has a frequency n times this frequency, is counted by a digital counter whose maximum count value is n, the resolution is 1 / n for one cycle. It becomes possible to measure the phase with This is 1/ for phase 2π
This means that it has a resolution of n. Since the phase 2π corresponds to one period pitch θ of the sinusoidal alternating position signal outputted by the position signal detecting means 5a, this digital position signal generating means corresponds to one cycle pitch θ of the alternating position signal with respect to the rotational position of the rotor 2. This means that the periodic pitch θ is interpolated (or interpolated) to 1/n at equal intervals. By the way, since the count content of the digital counter means 15a is a maximum of n digital harmonics, it is repetitive and has a discrimination ability only within the range of one period pifth θ of the alternating position signal.

Therefore, in order to enable length measurement within a wide range as required in an actual position control device, a reversible counter means 1 is used.
8a is provided to count the number of times the alternating position signal exceeds one cycle pitch θ. Reversible count pulse generation circuit 18b
The function of is that the content of the temporary holding means 15a is O (a value close to)
to n (a value close to), and from n (a value close to) to 0 (
Each time there is a sudden jump to a value close to , an up-count pulse and a down-count pulse are generated, respectively.
The data is sent to the reversible counter means 18a to count up and count down. Therefore, the reversible counter means indicates the upper bits of the position information, and the temporary holding means indicates the lower bits. The contents of the reversible counter means 18a and the contents of the temporary holding means 15b are combined and stored in the position register 19 as an upper bit part and a lower bit part, respectively.

2(a) is a block diagram of an embodiment of the digital position signal generating means 5b of FIG. 1 of the present invention, similar to FIG. 2(a). It has a similar structure. The difference lies in the configuration of the 17 digital sample holder means, which will only be described. Note that blocks having the same or equivalent functions as those in FIG. 2(a) are given the same names and numbers. Figure 2 (
Digital sample holder means 17 of the embodiment of (b)
is also the signal p (t, θ) for the carrier signal
It is used to find the phase difference (phase demodulation), and its purpose is exactly the same. Specifically, the first difference is that the sample-and-hold pulse forming means 13c forms the sample-and-hold pulse U from the carrier signal 16a. Accordingly, the digital harmonics generated by the digital counter means 15a are periodically reset by the reset pulse r generated from the reset pulse forming means 13d based on the signal P(t, θ). The signal P(t,
A digital harmonic wave is created based on θ) and is sampled and held using a carrier wave, thereby holding the phase difference between the two in the temporary holding means 15b. This method is exactly the opposite of the embodiment of FIG. 2(a).

In the embodiment shown in FIG. 2(a), equivalent digital harmonics are created based on the carrier wave, and the signal P
The configuration is such that this is sampled and held based on (t, θ). The example of the 2nd [Yes]) is (a
) is a little more complex, but achieves roughly the same functionality.

FIG. 3 is a block diagram showing a specific embodiment of the digital calculation means 6 of FIG. 1. In this embodiment, the comparison means 7, the electrical angle calculation means 8, and the function generation means 9 of the digital calculation means 6 are comprised of an A/D converter 21, a calculation unit 22, a memory 23 serving as a storage means, and a D/A converter 24a. , 24b. The A/D converter 21 converts a position input signal a applied from the outside to the position input terminal 7a into a digital signal. The arithmetic unit 22 includes an arithmetic processing unit means for performing calculations and a sequencer means for managing processing procedures, and a ROM 6 of a memory 23 serving as a storage means.
It operates according to a predetermined built-in program, which will be described later, stored in the X area (read-only memory area), and first calculates the output of the A/D converter 21 and then the position of the rotor 2 output from the digital position signal generating means 5b. The signals are captured and stored in the memory 23's registers and RAM? ii
(random access memory area), then performs predetermined digital operations including addition and subtraction processing, and then synthesizes to calculate the electrical angle amount e. Furthermore, the computing unit 22 obtains the two-phase signals sc and ss by referring to the sine wave and cosine wave function tables stored in the ROM t+i area of the memory 23 according to this electrical angle quantity e, and converts them into D/ It outputs to A converters 24a and 24b. The D/A converters 24a and 24b perform digital-to-analog conversion on the two-phase signals sc and ss, respectively, to generate two-phase analog signals sc and s.
Outputs s.

Note that if the position input signal a applied to the position input terminal 7a from the outside is a digital signal from the beginning, the A/D converter 21 can be omitted.

Next, an outline of the built-in program stored in the ROM area of the memory 23, which is a storage means, will be explained based on FIG.

FIG. 4 shows the RO of the memory 23 which is the storage means shown in FIG.
2 is a basic flowchart of an embodiment of a built-in program stored in an M area. First, assume that the program starts with ■. In the first process 31, an interrupt from the timer is waited for.

The timer generates an interrupt signal every predetermined time τ,
When an interrupt occurs, the process shifts to ■. That is, the following processing is performed every sampling time τ. Process 32 is information capture,
The position signal is taken in and stored in a predetermined register or RAN area Qb. Processing 33 is a control calculation, in which predetermined control calculation processing is performed based on the deviation signal C between the position input signal a and the position signal S in order to position the rotational position of the rotor 2 at the target position indicated by the position input signal. , generate an electrical angle signal g. Processing 34 is a restriction of the electrical angle signal g, which limits the magnitude within a predetermined range and outputs the electrical angle signal g. Processing 35 is the output of the result of adding correction calculations to the above calculation results, and is stored in the ROM of memory 23 according to the position signal of rotor 2 and the electrical angle signal obtained in processing 34.
After the 0 line processing, which refers to the sine wave and cosine wave function tables stored in the wi area, calculates the two-phase signals sc and ss and outputs them (to the D/A converters 24a and 24b, respectively), to move to.

Next, first, regarding processes 32 to 35 in FIG.
Figure (a), Figure 5 (b), Figure 5 (C), Figure 5 (B)
This will be explained in more detail using .

FIG. 5(a) is a flowchart of a specific example of the process 32 shown in FIG. First, in processes 36 and 37, the position input signal a and the position signal of the rotor 2 are input to respective predetermined registers or RAM 6M area Q8. Store in Qb. In process 38, the contents of a predetermined register or RAM file area Qn that holds the value at the time of the previous sampling are transferred to another Q.
Store in n-1. However, Qn is a register or RAM jI area that stores the digital signal corresponding to the deviation signal C between the position input signal a and the position signal S.
Now, the digital signal corresponding to the deviation signal C between the position input signal a and the position signal S is newly calculated (c=a-b), that is, the calculation of (Qn)=(Qa)-(Qb)),
This is stored in Qn. That is, at this point, the deviation signal between the current rotational position of the rotor 2 and the position input signal is stored in Qn, and the deviation signal from one sampling ago is stored in Qn-.
This means that it is stored in 1. The processing up to this point corresponds to the processing of the comparing means 7. Hereinafter, (Qn) represents the content of Qn.

5) is a flowchart of a specific example of the process 33 shown in FIG. First, in process 41, the contents of Qn, which holds the value corresponding to the current deviation signal c (-, a-b) between the position input signal a and the position signal S, are multiplied by 1, and the result is stored in a predetermined register or Store in RAM 8i area P. The content of P becomes an element proportional to the content of Qn. In process 42,
1 from Qn that holds the value corresponding to the current deviation signal C
Q that holds the value corresponding to the deviation signal C before sampling
The contents of n-1 are subtracted and the result is stored in a predetermined register or RAM 8N area ΔQ. In process 43, Q
Value obtained by multiplying the content of n by the sampling period τ (Qn)
- Calculate τ, add the contents of a predetermined register or RAM area 5n-1 one sampling before to the result, and store this in another Sn. That is, the following formula (4)
The calculation result is stored in variable Sn.

(S n) - (S n -1) + (Qn) ・r
...(4) In equation (4), the Qn content represents the deviation signal C between the position input signal a and the position signal S, and if there is a steady deviation between the position input signal a and the position signal S, then , for each sampling, the term (Qn) ・τ becomes (S
n-1). As a result, the content of Sn increases with time, so if a closed loop servo system is constructed based on this, the steady deviation between a and b can be eliminated.

If the sampling period τ is sufficiently small, Equation (4)
The content of Sn expressed by is the result of time integration of the deviation signal C. That is, the process 43 calculates the integral element obtained by accumulating the amount of deviation over time. Next, in the process 44, (Sn) is doubled and the result is stored in a predetermined register or RAM 61 area I. do. The content of ■ becomes an integral signal. Next, in process 45, the value (ΔQ)/τ obtained by dividing the contents of ΔQ by the sampling period τ is multiplied by 3, and the result is stored in a predetermined register or RAM area. That is, processes 42 and 45 are for finding a variational element by temporally differentiating the amount of deviation. The content of D becomes a differential signal.

In process 46, all the contents of P, I, and D of the calculation results obtained in processes 41, 44, and 45 are added to obtain an electrical angle signal g.
and store the result in a predetermined register or RAM
Store in 6N area G. Then move on to ■.

The above processing is what is called PID compensation from the perspective of a control system, and it gives stability to the system and also improves stiffness (position holding force when external vibration is applied) and position followability for position input signal a. It is something that makes it possible to improve.

FIG. 5(C) is a flowchart of a specific example of the process 34 shown in FIG. In process 48, the absolute value of the electrical angle signal g obtained in process 33 and a preset constant g WA
Compare with X. When g>gMAX, the process moves to process 49. If not, in step 50, g is stored in a predetermined register or RAM area H, and the process directly proceeds to (2). Processing 4
In step 9, the code is retained and its size is set to g WAX, which is also stored in H and the process moves to ■. This H signal is called an electrical angle signal. This processing 34 limits the electrical angle amount to a predetermined range, and this processing is called electrical angle limitation. The detailed function and principle will be described later.

FIG. 5(b) is a flowchart of a specific example of process 35 in FIG. In process 56, the electrical angle signal RI obtained in process 34 and the position signal S are added to obtain an electrical angle quantity e, which is stored in a predetermined register or RAM area E. This is the main processing of the electrical angle calculation means 8. In process 57, the function table of the cosine wave stored in the ROM area of the memory 23 is calculated according to the electrical angle amount e obtained in process 56 (usually, the upper bits of e are rounded down and the lower bits are truncated). By referring to it, the cosine wave signal 5C=fc(e) is obtained. Similarly process 5
8, ROMjI of the memory 23 is set according to the electrical angle amount e.
The sine wave signal 5S=fs(e) is obtained by referring to the sine wave function table stored in the area. Finally, the two-phase body numbers sc and ss are D/A converters 24a and 2, respectively.
4b. The above is the main processing of the function generating means 9. (In addition to the subsequent operations, see Figures 1 and 3.
To explain with a diagram, the D/A converters 24a and 24b convert digital signals sc and ss into analog signals sc, respectively.

ss and applied to the biasing means 9, respectively.

The two-phase body numbers sc and ss are amplified by the biasing means 9 and become sc
, two-phase current signal (or voltage signal) proportional to ss
and is supplied to two-phase coils 3a and 3b wound around the magnetic core of the stator 3. )The program flow then shifts to step 2 at the beginning of FIG. 4 and waits for the next timer interrupt.

Hereinafter, the functions and operations of the position control device in one embodiment of the present invention shown in FIG. 1 will be further explained with reference to the accompanying drawings. First, the principles of torque generation and position control will be explained based on FIG.

FIG. 6 is a conceptual diagram showing the torque generating mechanism of the drive means shown in FIG. 1. In FIG. 6, 3a and 3b are two-phase coils. Φ. indicates the magnetic pole vector of rotor 2 (for simplicity, the rotor is assumed to include a magnet with a pair of magnetic poles, but in practical terms, it is assumed that the rotor includes a magnet with a multipolar pair or a multipolar magnetic pole tooth). The zero position detection means 5a detects the magnetic pole vector Φ with respect to the coils 3a and 3b.
. It also has the function of detecting the relative rotational position of the

This relative rotational position is expressed as b, which has an arbitrary relative reference position as its origin, and its range is 2π
(=360 degrees). If the currents flowing through each phase are Ia and L, respectively, the torque generated in each phase is expressed by the following equation.

A phase -K t-1a ・SIN (b) --
(5a) B phase Kt・■1・SIN (π/2−b
)=Kt −Is ・CO5(b) ・・・・
(5b) (Kt+) torque coefficient, b: rotor position signal) The current supplied to the two-phase coils 3a and 3b of the stator is the two-phase body code sc output by the function generating means 9.

It changes sinusoidally according to ss. The function generating means 9 has an electric angle amount e (=
b+h) is input, and a two-phase sinusoidal signal sc corresponding to e is input.
, ss are output. Therefore, the current supplied to each phase of the coils 3a and 3b is the two-phase body number sc output by the function generating means 9.

Since it is proportional to ss, it is expressed as follows.

IA=Io -CO5(b+h) ・-(6a
) Ia-1o -5IN (b + h)
=・=・(6a) (where ■o: current peak value) This means that the combined current magnetomotive force Φi of coils 3a and 3b
This means that it is formed at position b+h as shown at 61 in FIG. By the way, at this time, the overall generated torque is as follows from equations (5a) and (5b) and equations (6a) and (6b).

T=Kt-1o (-5IN (b)・CO5(b+
h) + COS[with])・SIN (b+h))=
K t ・I o −5IN (h) −
-(7) In this position control device, when a position signal is input, the phase of the composite current magnetomotive force Φi of multiple coils is calculated based on this b and the deviation signal C of the position input signal a. This means that the position of the rotor can be controlled by freely adjusting it. That is, by controlling the variables according to equation (7), the generated torque T can be changed to provide an arbitrary positioning characteristic. Now rotor 2
If the value of the position of is b - Δb and the value of the position input signal a is b, the deviation signal C becomes Δb, h is calculated based on this, and torque is generated according to equation (7). Therefore, the rotor 2 is rotated until Δb becomes zero. Finally, the position of the rotor 2 becomes b, and Δb, h, and torque become zero. Further, the electrical angle calculation means 8 obtains the electrical angle signal g by combining the proportional element, variational element, and integral element of the deviation signal C output from the comparison means 7. Since the electrical angle amount e is based on g, damping can be electrically applied to the control system by the action of the variational element, which is a time differential signal. Therefore, the vibration of the rotor 2 that occurs during positioning can be eliminated and the settling time can be shortened. Furthermore, the steady-state deviation that occurs between the position input signal a and the position signal S can be suppressed by the action of the integral element included in the electrical angle quantity e. This is due to the following reason. In other words, when a deviation occurs between the position input signal a and the position signal due to friction or load, the deviation signal c (=a-b) does not become zero, so the integral element increases with time according to equation (4). .

This acts to gradually bring the position signal (a) closer to the position input signal (a), thereby suppressing steady-state deviation.

Next, the function and principle of the electrical angle limiting means in the process 34 shown in FIG. 4 or FIG. 5(C) will be explained based on FIGS. 7 and 8.

FIG. 7 is a static torque characteristic diagram of one embodiment of the driving means of the position control device of the present invention shown in FIG.

The vertical axis is the generated torque T, and the horizontal axis is the electrical angle amount e.As shown in equation (7), the generated torque T is a sine wave function of the electrical angle signal, so as h increases from 0. The generated torque T increases as Decrease. Furthermore, when h exceeds π [rad] and reaches the point e=e2 in Figure 7, the sign of the generated torque is reversed and a torque T2 is generated in the opposite direction to the command, making the control system unstable. In the worst case scenario, you will lose control. Therefore, it is necessary to limit the absolute value of the electrical angle signal so that it does not exceed π/2 [rad].

FIG. 8 is a characteristic diagram showing an example of the limiting characteristics of the electrical angle limiting means of the process 34 shown in FIG. 4 or FIG. 5(C). Here, the absolute value of the electrical angle signal g is compared with a predetermined constant gNam (=g/2 [rad]), limited to this range, and the result is used as the electrical angle signal. This makes it possible to limit the manipulated electrical angle amount e to a certain range. With this configuration, the absolute value of the electrical angle signal calculated by the electrical angle calculation means is π/2[
rad], the operation amount (electrical angle amount e) can be set so that the generated torque becomes the maximum torque, and efficient acceleration/deceleration can be performed. In this way, when the rotor 2 is given the target position a by the position input signal,
It moves and rotates smoothly to that position without losing synchronization.

In this embodiment, the limit value is gI4AX=π/2, but it goes without saying that stable acceleration/deceleration can be performed as long as the limit value is less than or equal to π.

In the above-described embodiment, a motor having magnetic pole teeth, such as a so-called stepping motor, can be applied to the mechanical part of the driving means.

For example, as shown in the structural diagrams of FIGS. 9(a) and 9(b), either the rotor or the stator is equipped with a magnetic body 72 having magnetic pole teeth 71 carved at a constant pitch, and either On one side, a magnetic core 74 having a plurality of magnetic pole tooth groups 73 is provided.
and a plurality of coils 75 wound around this magnetic core.
(Type) stepping motor can be applied.

In addition, as shown in the structural diagrams of FIGS. 10(a) and 10(b), either the rotor or the stator is equipped with a multi-pole magnetized permanent magnet 81. Magnetic core 8 having a plurality of magnetic pole tooth groups 82 facing the magnet
3 and a plurality of coils 85 wound around this magnetic core.
A stepping motor of the following type can be applied.

Furthermore, as shown in the structural diagram of FIG. 11(a), Φ), either the rotor or the stator is provided with a magnetic body 92 having magnetic pole teeth 91 carved at a constant pitch. On one side, a hybrid PM type stepping system is equipped with a magnetic core 94 having a plurality of magnetic pole tooth groups 93, a plurality of coils 95 wound around the magnetic core, and a permanent magnet 96 that generates a magnetic field through a via. Motors can also be applied.

In addition, (a) and (b) in Fig. 13 shown in the conventional example
As shown in the figure, one of the rotor and stator is equipped with a magnetic material having magnetic pole teeth carved at a constant pitch and a permanent magnet that generates a bias magnetic field, and one of the rotor and stator is equipped with a plurality of groups of magnetic pole teeth. A hybrid PM type stepping motor including a magnetic core having a magnetic core and a plurality of coils wound around the magnetic core can also be applied.

Motors equipped with magnetic pole teeth like these can obtain large torque with a small amount of current, so by applying them, it is possible to save power and make the device smaller and more compact.

FIGS. 12(a), 12(b), and 12(c) show specific embodiments of the position detecting means 5a of the present invention shown in FIG. 1, respectively.

FIG. 12(a) is an embodiment of a position detection means using a plurality of magnetically sensitive elements that magnetically detect magnetic pole teeth carved at a constant pitch. In FIG.
102 is a detection bias magnet. The magnetoresistive element has a detection bias magnet 1 placed behind it.
02 is applied. As the magnetic pole teeth 101 carved at a constant pitch move on the front surface, this magnetic field is modulated and outputs a multi-phase sinusoidal alternating position signal.

FIG. 12(b) shows an embodiment of a position detecting means using a plurality of magnetic sensing elements for magnetically detecting a multipolar magnetized permanent magnet. In the figure, reference numeral 104 denotes a Hall effect element, which outputs a multi-phase sinusoidal alternating position signal as the multipolar magnetized permanent magnet 105 moves.

FIG. 12(C) shows an embodiment of a position detection means using an optical detection element that optically detects the relative movement of the rotor and stator. In the figure, 107 is a slit plate, and 108 is an optical detection element having a light emitting element and a light receiving element facing each other. The slit plate is provided with a striped pattern or striped holes, and as the slit plate moves, it outputs a sinusoidal alternating position signal of multiple phases. In addition, in FIG. 12(C), it is also possible to use magnetic pole teeth 109 carved at a constant pitch instead of the slit plate, and to pick up the magnetic pole teeth 109 with the above-mentioned optical detection element.

Although the driving means in the embodiment shown in FIG. 1 is a two-phase, two-coil motor, the same effect can be obtained using three or more phases or three or more coils. Accordingly, the number of phases of the function generating means 9 and the urging means 10 should be changed. There is no restriction that the function of the function generating means 9 must be a sine wave of 5INE or C03INE, but it must be a repeating periodic waveform, and the function must be a function that generates a waveform that corrects the distortion of the torque waveform generated by the driving means. is also allowed.

Furthermore, although the present invention has been described in detail using a rotary motor as the drive means, it goes without saying that a drive means that performs linear motion such as a linear motor can also be applied.

Furthermore, in the above explanation, the rotor position detection means 5a of the drive means is directly connected to the rotating shaft of the motor.
It can also be attached to a movable member that is driven, such as a controlled object. It goes without saying that its shape does not have to be rotary, but may be linear, and its output does not necessarily have to be two-phase or a sine wave; it can be three or more phases.

Furthermore, in the embodiments shown in FIGS. 3 and 4, each process has been explained using software, but hardware processing may also be used.

Effects of the Invention As explained above, the position control device of the present invention has the following effects. First, the relative position of the movable element and the stator of the driving means is detected by the position detection means, and from this position detection means, relative position information between the movable element and the stator is digitally generated with high resolution. By determining the deviation between the position input signal and the position input signal from the outside, and optimally controlling the amount of operation for the drive means using digital calculation means based on this, the torque of the drive means can be generated efficiently at all times. The controlled object can be moved at high speed without causing step-out.Furthermore, the position controlled object can be quickly settled at the target position while vibrations are suppressed.Also, the position detection means and the digital position information generation means This enables high-resolution positioning control.Furthermore, by using digital calculation means, higher stiffness than before can be easily obtained.

[Brief explanation of drawings]

1 to 12 relate to the present invention, and FIGS. 13 to 17 relate to the conventional example. FIG. 1 is a block diagram of a position control device according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are blocks of an embodiment of the digital position signal generating means 5b of the present invention shown in FIG. 3 is a block diagram showing a specific embodiment of the digital calculation means 6 of the present invention shown in FIG. 1, and FIG. Basic flowcharts of one embodiment of the built-in program, Fig. 5(a), Fig. 5(b), Fig. 5(C), Fig. 5.
Figure (d) is a detailed flowchart of a specific example of processes 32 to 35 in Figure 4, Figure 6 is a conceptual diagram showing the torque generation mechanism of the drive means of the present invention shown in Figure 1, and Figure 7 is Fig. 1 is a static torque characteristic diagram of an embodiment of the driving means of the position control device of the present invention, Fig. 8 is a block diagram of the embodiment of Fig. 4, Fig. 12 (a), (b), ( C) is a block diagram showing the principle of a hybrid PM stamping motor as a drive means of the specific device of the position detection means 5a of the present invention shown in FIG. 1, and FIG. 14 is a diagram showing the conventional position control shown in FIG. 13. 15 is a basic drive circuit diagram for driving the stepping motor of the drive means of the device; FIG. 15 is a diagram showing the rotation angle-torque characteristic of the stepping motor of the drive means of the conventional position control device shown in FIG. 13; and FIG. The figure shows the basic configuration of a conventional position control device that uses a stepping motor as a driving means. Figure 17 shows a conventional position control device that uses a stepping motor as a driving means. FIG. 1... Drive means, 2... Rotor, 2a
...Permanent magnet, 2b...Magnetic pole tooth, 3.
...Stator, 3a. 3b...Coil, 4...Position control object, 5a...Position detection means, 5b...Digital position signal generation means, 6...... -Digital calculation means, 7...Comparison means, 8...Electrical angle calculation means, 9...Function generation means, 10.
...Biasing means, 12a, 12b...Modulation means, 13a...Synthesizing means, 13b...
-Low pass filter means, 14a...Carrier signal generation means, 14b...Reference clock signal generation means, 15a...Digital counter means,
15b...temporary holding means, 16a, 16b...
...Carrier signal, 17...Digital
Sample holder means, 18a... Reversible counter means, 19... Position register, 22...
...Arithmetic unit, 23...Storage means (memory). Name of agent Patent attorney Shigetaka Awano (1 person) Figure 3 Figure 4 Figure 5 (CLn <b) Figure 5 Figure 6 2-Usen Zshi 2b-Sem IgLt Figure 7 Figure 9 Figure 10 (OJ) Figure 11 Figure 12 Figure 13 Figure 14 Figure 16 Figure 17 E8 lock also

Claims (17)

[Claims] (1) A driving means including a movable element and a stator capable of moving the movable element by applying a relative motion force to the movable element; In order to digitally generate relative position information between the movable element and the stator from the position detection means, the position detection means outputs alternating signals of a plurality of phases with different phases. digital position information generating means including carrier signal generating means for generating a carrier signal modulated by an alternating signal and digital sample holder means for demodulating phase information of the modulated carrier signal; digital calculation means for calculating the amount of operation for the drive means based on the deviation between the relative position information between the child and the stator and the position input signal from the outside; A position control device comprising a biasing means for biasing. (2) Either the mover or the stator is equipped with a magnetic body having magnetic pole teeth carved at a constant pitch, and either of the mover and the stator is equipped with a magnetic core having a plurality of magnetic pole tooth groups facing the magnetic pole teeth. The position control device according to claim 1, further comprising: a plurality of coils wound around the magnetic core. (3) Either the mover or the stator includes a magnetic body having magnetic pole teeth carved at a constant pitch and a permanent magnet that generates a bias magnetic field, and either of the mover and the stator includes a plurality of magnetic poles facing the magnetic pole teeth. 2. The position control device according to claim 1, comprising: a magnetic core having a group of teeth; and a plurality of coils wound around the magnetic core. (4) Either the mover or the stator includes a magnetic body having magnetic pole teeth carved at a constant pitch, and either of the mover and the stator includes a magnetic core having a plurality of magnetic pole tooth groups facing the magnetic pole teeth. 2. The position control device according to claim 1, further comprising: a plurality of coils wound around the magnetic core; and a permanent magnet that generates a bias magnetic field. (5) Either the mover or the stator includes a multi-pole magnetized permanent magnet, and one of the movers and the stator includes a magnetic core having a plurality of magnetic pole tooth groups facing the permanent magnet, and the magnetic core. 2. The position control device according to claim 1, further comprising a plurality of coils wound around a plurality of coils. (6) Claim (1) characterized in that the position detection means is configured to output substantially sinusoidal alternating signals having multiple phases different from each other in accordance with the relative movement of the movable element and the stator. ) position control device. (7) The position detection means according to claim (2), (3) or (4), characterized in that the position detection means is equipped with a plurality of magnetically sensitive elements that magnetically detect magnetic pole teeth carved at a constant pitch. The position control device according to any one of the above. (8) The position control device according to claim (5), wherein the position detection means includes a plurality of magnetic sensing elements that magnetically detect the multipolar magnetized permanent magnet. (9) The position detection means optically detects the relative movement of the movable element and the stator using magnetic pole teeth carved at a constant pitch or an optical scale, and the position detecting means optically detects the relative movement of the movable element and the stator. 7. The position control device according to claim 6, further comprising a photosensitive element that outputs an alternating signal. (10) The digital position information generating means includes a plurality of modulating means that modulates the carrier signal with a multi-phase alternating signal output from the position detecting means, a combining means that combines the modulated carrier signals, and a high 2. The position control device according to claim 1, further comprising a low-pass filter means for blocking frequency components. (11) The digital sample holder means includes a reference clock signal generation means, a digital counter means for counting the reference clock signal, and a temporary holding means for sample and hold, and the count of the digital counter means is controlled by the sample and hold pulse signal. The position control device according to claim 1, characterized in that the content is held in the temporary holding means. (12) The position control device according to claim (11), wherein the sample and hold signal is formed based on a carrier signal or a modulated carrier signal. (13) The digital calculation means digitally calculates a proportional amount that is proportional to the deviation between the relative position information between the mover and the stator and the external position input signal, and a differential amount that is the temporal variation of this deviation. 2. The position control device according to claim 1, wherein the position control device is configured to calculate the operation amount digitally based on the calculation result. (14) The digital calculation means digitally calculates an integral amount obtained by integrating over time the deviation between the relative position information between the mover and the stator and the position input signal from the outside, and based on this calculation result. 2. The position control device according to claim 1, wherein the position control device is configured to digitally calculate the manipulated variable. (15) The digital calculation means includes function generation means,
This function generation means includes a memory means in which data according to a certain function is tabulated, and is digitally predetermined based on the deviation between the relative position information between the mover and the stator and the position input signal from the outside. According to claim 1, the device is configured to perform the calculation, read data according to the certain function from the memory means according to the calculation result, and output this as a manipulated variable to the biasing means. 1) The position control device described above. (16) The position control device according to claim 15, wherein the data according to a certain function read from the memory means of the function generating means is a substantially sinusoidal wave of multiple phases having mutually different phases. (17) The digital arithmetic means includes a storage means for storing a program and predetermined data according to processing contents, a sequencer means for managing the processing procedure, and an arithmetic processing unit means for executing the arithmetic processing according to the program and data. The position control device according to claim 1, characterized in that the position control device comprises: