JPS605156B2 - electromagnetic positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic positioning device that positions a movable part of an electromagnetic drive device with high precision.

In conventional positioning devices, in order to perform positioning operations with high accuracy, smoothness, and speed, when the three components of position, velocity, and acceleration are negatively fed back, the detection part and the negative feedback part are
It was expensive and complicated.

It is an object of the present invention to obtain an inexpensive and simple device that performs high-speed, high-precision positioning operations. Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. Fig. 1 shows an electromagnetic drive part, and in the figure, 1 is a movable part made of a cylindrical or cylindrical magnetic material and having teeth at a constant pitch P on its outer circumferential surface parallel to the central pulp. be.

Reference numeral 2 denotes a fixed part that surrounds the movable part 1 at a certain distance and magnetically interacts with the movable part 1 to apply rotational force to the movable part 1.

3, 4, 5, and 6 are poles provided on the fixed part 2.

These plurality of poles 3 to 6 are each wound with excitation windings 7 and 8.
, 9, 10 generate teeth 11 of the movable part 1.
A magnetic circuit is formed with the magnetic circuit, and rotational force and positioning operation are applied to the movable part 1 by changing the magnetic path resistance of the magnetic circuit. Further, the surfaces of the plurality of poles 3 to 6 facing the teeth 11 of the movable portion are each cut at the same pitch as the pitch P of the teeth 11 of the movable portion. Next, the pitch P of the teeth 11 of the movable part 1 is set to 1
The relative positions of the teeth 12 of each of the poles 3 to 6 with respect to the teeth 11 of the movable part 1 will be explained assuming that the period is two stages and that clockwise rotation is normal rotation.

A is the pole 3 where the teeth 11 of the movable part 1 and the teeth 12 of the pole match.
phase, that is, zero phase, pole 4 is m/2 leading phase and B
The pole 5 is arranged so that it becomes the -A phase when it is in the stagnant, leading or lagging phase, and the pole 6 becomes the -B phase when it is in the lagging phase. Figure 2 shows the excitation windings 7, 8, 9, 10 of each pole 3 to 6.
2 is a diagram showing the phase relationship of each excitation current (control current) that flows once. FIG. The excitation winding 7 is wound around the pole 3 and carries the control current A phase, and the excitation winding 8 is wound around the pole 4 and carries the control current B phase.
The excitation winding 9 is wound around the pole 5, and the control current -A phase is passed through the excitation winding 101.The excitation winding 9 is wound around the pole 6, and the control current -B phase is passed through it. The electromagnetic drive unit shown in is a type of synchronous motor, and the movable part 1 (hereinafter referred to as rotor 1) rotates in synchronization with the phase of the control current.Therefore, if the phase of the control current is advanced, the rotor will rotate. If the rotor rotates in the forward direction and the control current phase is advanced in the opposite direction, it will rotate in the opposite direction.At the same time, if you want to stop the rotor at a certain angle in FIG. 1, you can stop the phase of the control current. Next, a device for controlling the phase of the self-control current will be explained. Fig. 3 is a block diagram of a device for controlling the positioning operation of the electromagnetic drive section. In the figure, 21
is a data input device such as a magnetic tape, a paper tape reader, or a computer; for example, the rotor 1 of the electromagnetic drive unit
When it is desired to rotate the motor by a certain angle a, this device inputs the angle 8 as data to a speed calculation section 22, which will be described later.

The speed calculation unit 22 receives the data angle 8, and changes the rotor from zero to 0. The rotational speed (angular velocity) c of the rotor 1 at which it should move at each moment during rotation is calculated and output.

FIG. 4 shows the relationship between time and angular velocity wc, which is the output of the velocity calculation section. Also, the output of the speed calculation section 22 is a pulse, and 1
A pulse means to rotate the rotor by a certain angle. The angular velocity c is expressed by the number of pulses per unit time, that is, the pulse density. For example, when performing speed control as shown in FIG. 4, the section a-b in the figure is an acceleration section, and the pulse density gradually increases from a to b. Between b and c is a constant velocity section and the pulse density is constant, c
-d is a deceleration section where the pulse density gradually decreases. Reference numeral 23 in FIG. 3 is a function generating section which receives the pulse signal output from the speed calculation section 22 and generates a plurality of phases of trigonometric functions with frequencies proportional to the pulse density.

In this example, two-phase trigonometric functions JA and OB shown in equation '1} are used.
Suppose that the function generator outputs . The above positive and cosine waves are N
One period is formed by inputting these pulses to the function generating section 23. In other words, the phase advances by 2 m. Therefore, when one pulse is input to the function generator 23, the phases of the positive and cosine waves advance by 2 lights/N.

At the same time, a direction signal indicating whether to rotate the movable part 1 in the forward direction or in the forward direction is sent from the data input device 21 to the function generating section 23 via the speed calculating section 22.
is input. The function generator 23 advances the phase of the output positive and cosine waves in the positive direction according to the direction signal, or
Decide whether to proceed in the negative direction. In FIG. 3, reference numeral 24 denotes a phase control section that controls the phases of the sine and cosine waves based on the output of the detection section 27 that detects the rotational position of the rotor 1.

However, for convenience of explanation, it is assumed that the positive and cosine waves are now input to the current intensifier 25 through the phase control circuit without any change. Note that the detection section 27 and the phase control section 24 will be explained in detail later. 25 is the positive output of the phase control section 24;
This is a current increasing part that supplies a current proportional to the instantaneous value of a cosine wave (control periodic function) to the electromagnetic drive part 26.

26 is the synchronous motor (reluctance motor) shown in Figure 1.
It is.

Therefore, the four-phase control current OA shown in formula ■, ? B. One? A,
one? B is the excitation winding 7 by the current multiplier 25,
8, 9, 10' washed away.

As can be seen from the above, the gear 1 rotates by one pitch P of its teeth 11 with the N pulses (one period of a positive and cosine wave) output from the speed calculation section 22.

That is, one pulse rotates by a P/N pitch. Therefore, by increasing N, the angle of rotation per pulse can be made infinitely small. Judging from the above explanation, it seems that positioning with a fairly high degree of precision is possible, but in reality, the movable part 1 is affected by the control current due to motor loads such as bearing friction of the rotor 1, movable objects applied to the rotor shaft, etc. Stops at a position out of phase.

The detection unit 27 and the phase control unit 24, which will be described from now on, detect the position of the movable part 1 and adjust the control current phase to zero the rotational position of the rotor and the control current phase. It is something. In a normal synchronous motor, the rotor always follows the control current phase at a certain angle depending on the load on the rotor.

Now, if the rotor position is called the mechanical phase with respect to the control current phase and can be expressed by a formula, then CMA is the rotor phase with respect to pole 3 (A phase)? For M old, in order to make the phase difference ◇ in the rotor phase glue formula for pole 4 (B phase) zero, the control current is {
It is obvious that the formula 4' should be used.

In the formula (2), K is a return constant, and the optimum value can be selected depending on the positioning control system. In this embodiment, the explanation will be made assuming that K=1. Reference numeral 27 in FIG. 3 is a detection unit for detecting the phase of the rotor 1 relative to the current phase 8, and the details are shown in FIG.

In FIG. 5, 31 is a sensor ring made of a magnetic material or a conductor, and is attached to the rotor 1. Also, teeth 31a provided on the sensor ring.・…． ... is the same as the pitch P of the teeth 11 of the rotor 1. 32 is a sensor, which is provided at a certain distance from the sensor ring 31.

Also, the mutual relationship with the tooth 11 of the rotor 1 is that the tooth 1 of the pole 3 (A phase)
2 and the rotor teeth 11. Further, the inductance at both ends of the coil 41 wound around the sensor 32 changes periodically as the sensor ring 31 rotates. The B-phase sensor 33 has the same function as the sensor 32, and its relationship with the teeth 31a of the sensor ring 31 is the same as the relationship between the teeth 12 of the pole 4 (B-phase) and the teeth 11 of the rotor. Changes in inductance at both ends of the sensor coils 41 and 42 due to changes in magnetic resistance of the magnetic path formed between the sensor 32 or the B-phase sensor 33 and the sensor ring 31 are caused by the change in inductance between the teeth 31a of the sensor ring 31 and the sensor 32 or the B-phase sensor. By appropriately forming the shape of the 33 teeth, a trigonometric function can be expressed as a side equation. As you can see from the above explanation [
Equation 5) represents the mechanical phase of the rotor. Therefore, what a
◇MA and b in formula [3} and MB in formula {3' are equivalent. 34 is an A-phase inductance detection circuit that detects the inductance of the coil 41.

(Output a) 35 is a B-phase inductance detection circuit that detects the inductance of the coil 42.

(Output b) 36 and 37 are differentiating circuits, 38 and 39 are multiplication circuits, and four-way subtraction circuits, which output the sensoring, that is, the angular velocity Wo of the rotor by performing the calculation of the formula {6--.

lol.

= float b + study x...・．． ．．・24 in shelf diagram 3
By adding, subtracting, multiplying, and dividing the phases A and JB of the function generator 23 and the outputs a and b of the detector 27, the phases (control period functions) OAC and GBC of the control current with negative position feedback are generated. This is a phase control section.

FIG. 6 shows a detailed diagram of the &phase control section 24.

The phase control unit 24 generates control currents ◇AC and JBC by calculating the following equations. The function of each element will be explained according to the following equations. OAC=cos(a+○)=O
AX (go a
A+DobXOB) 10OA(Goa◇B-Gob?B)……
In the figure, 51 is a multiplication circuit that multiplies a x OA.
52 is a multiplier circuit that multiplies b x OB, 55 is an adder circuit that sums the outputs of multiplier circuits 51 and 52, and the output is cos
I can express it visually.

53 is a multiplication circuit that multiplies a x OB, and 54 is a multiplication circuit that multiplies a x OB.
? A multiplication circuit that multiplies A, 56 is a multiplication circuit 53 and 54
This is a subtraction circuit that calculates the output difference, that is, a×OB−gob×OA, and the output is expressed as the sine.

57 fit A×cos? A multiplication circuit 58 is O
A multiplication circuit that performs multiplication of Bxsin◇, 71 is a multiplication circuit 5
The difference between the outputs of 7 and 58, i.e. OA x COS - OB x Si
n? This is a subtraction circuit that performs calculations, and the output can be expressed as AC.

59 fit B×cos? 72 is a multiplication circuit 5.
The sum of the outputs of 9 and 60, that is, OB x cos 0 OA x si
This is an adder circuit that performs the nth operation, and the output can be expressed as BC.

73 and 74 are inverters, OAC and OBC respectively.
Calculate -1 to 1? Outputs AC and one OBC.

As can be seen from the above explanation, the phase control unit 24 also performs negative feedback of the position component of the control current OAC, ? You can get BC. Next, referring to FIG. 7, another embodiment will be described.

FIG. 7 shows another embodiment of FIG. 3, and corresponds to claim 2. The above embodiment is obtained by adding negative feedback of the velocity component to the phase control section 24 that performs negative feedback of the position component shown in FIG. 6, and is realized by performing the calculations shown in the equations a and b below. . Note that elements with the same numbers in FIG. 6 and FIG. 7 operate in the same manner, so their explanations will be omitted. ◇ACic.

s8×(cos small ten fXSin small)−Sin8×(S
inJ+■fXCOSJ)=Cos(80Jhi)...{
81abJBC;Sin8×(COS?10 fXSin
○) 10 cosOX (10 fXc in Sin. s○) = Si
n (800hi)...[8}bHowever, fni's L-1's 0? h=sin-1 (fXCOS○ of Sin○1) The function of each element will be explained below.

61 is a differentiation circuit that differentiates ◇A, 62 is a differentiation circuit that differentiates ◇B, 63 is a multiplication circuit that multiplies the output of the differentiation circuit 61 and OB, and 64 is a multiplication circuit that multiplies the output of the differentiation circuit 62 by A. , 61 is a subtraction circuit that takes the difference between the outputs of the multiplication circuits 63 and 64, and the output can be expressed as ''.

66 is a subtraction circuit which takes the difference between ↓ and o, and the output is expressed as f.

The above f indicates the velocity component caused by the extra movement of the movable part 1 with respect to the angular velocity wc of the output of the function generating part 23. 67
is a multiplication circuit that multiplies the above f by the sin foot, and the f is cos? It is converted into a phase component for .

68 is a multiplication circuit that multiplies the above f and cos,
f is converted into a phase component for sin◇.

Reference numeral 69 denotes an adder circuit that calculates the sum of the output of the multiplier circuit 67 and cos◇, and this circuit provides negative feedback to the control current of the angular velocity component.

This adder circuit has the same function as the adder circuit 69, and calculates the sum of the output of the multiplier circuit 68 and sin◇.

In fact, it is more effective to multiply the feedback value of f by a feedback constant called Kf to determine Kf so as to enable optimal control of the positioning control system to be used.

In the above two embodiments, the method of negative feedback of the position component and velocity component was shown, but if negative feedback of the acceleration component (angular acceleration component) is performed in addition to this method, it will be more effective in the positioning control system.

Since f in the embodiment of FIG. 7 has been obtained, by differentiating f, the angular acceleration component to be negatively fed back can be obtained, and if performed in the same manner as the negative feedback method of the velocity component in FIG. 7, It is clear that negative feedback of the angular acceleration component can be obtained.

Further, although the detection section in this embodiment is an electromagnetic one, it is obvious that other detection methods such as optical detection are also possible.

Alternatively, in FIG. 5, the sensor ring 31 may be fixed and the sensors 32 and 33 may be attached to the movable part. To summarize the above, a synchronous motor as shown in FIG. 1 can be expressed very simply as shown in FIG. 8.

In the figure, 81 represents the mass of the load applied to the rotor shaft (including the mass of the rotor itself). 82 represents a spring constant corresponding to the driving force of the electromagnetic drive section.

83 represents windage loss or viscous loss due to eddy current or the like.

84 is a fixed part.

Therefore, in this figure, moving the electromagnetic drive section means moving the fixed section 84. The load 81 at this time becomes the movement of the rotor. As can be seen from the system shown in FIG. 8, considering the control current phase for the movement of the fixed part 84, the movement of the rotor 1, that is, the movement of the load 81, has a certain deviation angle of 0 with respect to the movement of the fixed part 84. Follow. The angle J at this time is the spring 82
corresponds to the growth of

Furthermore, in reality, fixed friction always acts on the load 81, and even if the fixed portion 84 is stopped at a certain point, the load 81 will stop at a position shifted from the point where it should stop. The present invention improves the lower condition of the system shown in FIG. 8, and by performing negative feedback of the positional component, the spring constant K can be made very large, and the above-mentioned control current phase is adjusted to the position of the fixed part 84 and the load 81K. The positional deviation can be brought close to zero. Next, in a quadratic system as shown in Figure 8, each element 8
Depending on the size of the fixed portions 1, 82, and 83, a resonance phenomenon may occur, and in the worst case, the load 81 may not be able to follow the movement of the fixed portion 84 at all.

Therefore, by feeding back the velocity component negatively, the value of the viscous loss 83 can be determined so that the system does not cause resonance. Generally, the inertial force due to the load 81 occurs at a point where the speed of the fixed part 84 changes, impairing the quickness of the entire system, and the load 81 is likely to vibrate at the point where the inertial force acts. The present invention can solve this problem by calculating the acceleration of the movable part of the electromagnetic drive unit and controlling the phase of the control function in response to the calculated acceleration signal. As can be seen from the above explanation, the present invention enables position, velocity, acceleration, and
Or negative feedback of a combination thereof is now possible.

As a result, it is possible to obtain a device that performs positioning operations quickly and smoothly with high precision, which has been considered difficult in the past.

[Brief explanation of the drawing]

The figure shows an embodiment of the invention. Figure 1: Schematic diagram of electromagnetic drive unit, Figure 2: Phase relationship diagram of control current (excitation current), Figure 3: Block diagram of electromagnetic positioning device, Figure 4: Control speed (angular velocity) diagram, Figure 5 Figure: Detailed view of the detection unit, Figure 6: Phase control unit for feedback of position component, Figure 7: Phase control unit including negative feedback of velocity component, Figure 8: Outline of electromagnetic drive system. figure. 1...Movable part, 1, 2...Electromagnetic drive part, 25...
Current increasing part, 27...Detection part, 23...
-Function generation section, 24... Phase control section. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. An electromagnetic drive unit comprising a movable part having teeth of a constant pitch, and a fixed part having a plurality of poles facing each other with a phase difference with respect to the teeth of the movable part; A function generating section that generates a periodic function of multiple phases, and a current amplification section that generates control currents corresponding to the plurality of poles using the periodic function, and the electromagnetic drive section is controlled by the control current. The device for controlling the position, speed, etc. has at least one pair of sensors provided on the fixed part of the electromagnetic drive part and arranged facing each other with a phase difference with respect to the teeth of the movable part. A detection unit that generates a detection signal having the same period as a periodic function; and a phase control unit that performs addition, subtraction, and multiplication operations on this detection signal and the periodic function to generate a control periodic function in which the phase of the periodic function is corrected. An electromagnetic positioning device characterized in that the control periodic function is inputted to the current amplification section to provide negative position feedback to the movable section. 2. The product of the differential value of the A-phase detection signal and the B-phase detection signal, and the differential value of the B-phase detection signal and a detection unit that detects the speed of the movable part by adding the product of the A-phase detection signals; and a detection unit that detects the speed of the movable part by adding and subtracting the detected speed signal detected by this detection unit and the periodic function. 2. The electromagnetic positioning device according to claim 1, further comprising a phase control section for obtaining a control periodic function whose phase is corrected in accordance with the phase control function. 3. A differentiation circuit for differentiating the detection speed is provided in the detection section,
A phase control unit that calculates the acceleration of the movable part of the electromagnetic drive unit and controls the phase of the control periodic function in response to the acceleration signal by performing addition, subtraction, and multiplication operations on the calculated acceleration signal and the periodic function. An electromagnetic positioning device according to claim 2, characterized in that: