JPS63171187A - Controller for linear dc motor - Google Patents

Abstract

PURPOSE:To need no arithmetic unit of deviation signal and no amplifier generating the output of current according to the deviation signal, by selecting the phase of polyphase coils in an arbitrary cycle till a command value coincides with the output value of a position detector, and by feeding current. CONSTITUTION:A movable section 2 is provided with two-phase motor coils 10A, 10B, two holes IC20A, 20B, and the scale head 6 of a position detector. By a comparator 4, a command value(a) and the position(b)of the movable section are compared with each other, and the output of '1' is directed to an output wire 41 when the command value(a) > the position b, and to an output wire 42 when the command value(a)= the position b, and to an output wire 43 when the command value(a) < the position b. From a current feeder 3, according to output signal from the comparator 4 and the signal of the holes IC20A, 20B, current is fed to the motor coils 10A, 10B in an arbitrary cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning device that drives a linear DC motor intermittently like a stepping motor.

[Conventional technology]

Conventional positioning control for linear DC motors is described in Japanese Patent Application Laid-open No. 57
As described in No. 149179 and Japanese Unexamined Patent Publication No. 59-103559, the state quantity of the motor is fed back and a voltage or current corresponding to the deviation from the command value is supplied to the motor for control. Such a control device is expensive, and is disadvantageous in terms of cost when precision and smooth movement are not required. [Problem to be solved by the invention] The above-mentioned conventional technology requires a complicated method to obtain a deviation signal. An arithmetic circuit is required, and an expensive amplifier is also required to supply the voltage, voltage, or current according to the deviation signal, which poses a problem in that the cost of the control device is limited.

An object of the present invention is to provide a control device for a linear DC motor that has a simple drive control method and is inexpensive.

[Failure to solve the problem]

A multi-phase linear DC motor can be driven intermittently like a stepping motor by selecting a phase of a multi-phase coil at an arbitrary period and supplying current to that phase. Therefore, the positioning control of the linear DC motor can be performed by selecting the phases of the various coils at arbitrary intervals and supplying current to the phases until the command value and the output value of the position detector match.

The above-mentioned control ellipse does not require a deviation signal calculator or an amplifier that outputs a current according to the deviation signal, resulting in low cost.

[Effect]

The phase of the multiphase coil is selected at an arbitrary cycle and current is supplied to drive the motor until the command value and the output value of the position detector match. With this method, the motor reliably moves to the commanded position and stops, so positional deviations due to step-out and the like do not occur.

Here, step-out will be explained. When the phases of a multiphase coil are selected at an arbitrary period and a current is supplied, the coil moves at a fixed pitch every - period. Therefore, if a certain number of pulses are given, phases are selected in that cycle, and current is supplied, the amount of movement becomes the amount of movement x the number of pulses.

However, if the period of the pulses is shortened, the movement of the motor will no longer be able to follow, the motor will not be able to move up to the amount of movement pitch, and a fixed movement pitch corresponding to the period will not be obtained. This is called step-out, and when this occurs, the amount of movement corresponding to the number of command pulses cannot be obtained, and positioning and stacking deteriorates.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 10.

FIG. 1 shows the configuration of the control device.

1 is the stator magnet of the linear DC motor, 2 is the moving part of the linear DC motor, and the moving part 2 includes a 2-phase motor coil + OA, IOB, 2 holes tC20A, 20B, and a scale head of a position detector. It is equipped with 6. 5 is a scale of a position detector attached to the stator 01lI. 4 is a comparator that compares the command value a and the position of the movable part, and when a>b, outputs 1 to the output line 41;
2.43 outputs 0. When a=b, output line 4
Outputs 1 to 2, outputs 0 to output i41.43, and a
When <b, 1 is output to the output line 43, and the output line 41.4
Outputs 0 to 2. 3Vi current supply with output signal 41.42.43 from comparator and Hall 1c20A,
According to the signal of 20B, the motor coil 10
Supply AiOBVC current.

2 to 4 show the entire structure of a linear DC motor. As shown in Figure 2, the U-shaped outer wall <7
Magnets 1 are attached to both sides of the inside of the U-shaped opening, and the motor coil 10 with the hole i C20 attached is inserted into the magnetic space formed by the magnets 5 attached to both sides, and the motor coil 10 is fixed to the movable part 2. A scale 5 for position detection is attached to the outside of the outer frame 7, and a scale head 6 is attached to the movable part 2.
is fixed. The movable part 2 is guided by a linear guide rail 8 and a linear guide rail, and is movable in a direction perpendicular to the plane of the paper. FIG. 3 shows the entire cross section taken along the line AA in FIG. The magnets 1, which are magnetized in the thickness direction and have a width of p, are arranged so that opposing magnets have different polarities, and adjacent magnets also have different polarities. FIG. 4 shows a BB cross section in FIG. 2. 10 motor coils.

10B is a ring shaped like a mouth.

The width of the ring is TI) as shown in FIG. 3, and the outer dimension in the direction of movement of the ring is 7P. Hall 1c2QA
is installed between motor coils +OA and +OB, and hole 1c2Q13 is installed at the right end of motor coil IOB.

FIG. 5 shows a position detector for detecting the position of the movable part 2. As shown in FIG. 5' is a school having a width 71), which is half the width p of the magnet 10, on the absolute scale, and is attached to the stator side. The addresses of the absolute scale 5' increase toward the left, and the addresses are represented by integer values. The absolute scale 5' is attached so that the boundary where the address changes is shifted by 7p from the boundary of the magnet 1. Figure 6 shows an absolute scale 5'' in which the address widths of the absolute scale 5' in Figure 5 are arranged at unequal intervals from 1 to 1, and the address width is an integral multiple of 71).Absolute scale The linear DC motor can be driven and controlled even if the distances are unequal as shown in FIG.

FIG. 7 shows the current supply device. A signal line 41 indicating whether a>b is input to an AND circuit 32A. The signal line 42 of a=b is input to the NOT circuit 33 and N
The output signal of the OT circuit 33 is input to AND circuits 32A and 32B. The signal line 43 of a<b is AND circuit M32
It is input to B. 34 is a pulse generator that generates pulses at an arbitrary period, and its output signal is a 1dAND circuit 32A.
.

32B. With these configurations, it is possible to generate a signal to move the linear DC motor to the left or to the right. For example, when the position of the motor movable part 2 is smaller than the command value a (a>b), a pulse signal is output from the AND circuit 32A to the signal line 44 in order to move the movable part to the left. When 1<, a<b, a pulse signal R is output from the vcAND circuit 32B to the signal line 45 in order to move the movable part 2 to the right. AND when a=b
A signal in the 0 state is output from the circuits 32A and 32B. 31 is a current divider, AND circuits 32A, 32B
The output signals from the holes 1c2OA and 20B are input. Current divider 31 supplies motor coil IOA, 1OBVC current according to their input signals. Next, the motor coil +O of the current distributor 31
A method of supplying current to A and 10B will be explained with reference to FIGS. 8 to 10. Figure 8 shows a motor coil 10AiOB.

This is a modeled representation of the arrangement relationship between the holes 1c2QA, 20B and the magnet 1. Figure 9 shows motor coil + OA
, 10B shows the current supply pattern. FIG. 10 is a diagram illustrating the direction in which the coil current flows using the symbol r used in FIG. 9. First, when the motor coil is located at the position ■ in Figure 8 as in pattern O in Figure 9, when a current is supplied in the motor coil l0BIC+ direction, a force in the right direction acts on the motor coil Vc, causing it to move to the right. The force balances and it stops at the position marked ◎, which has moved by -1-I). Next, as shown in the pattern @ in Figure 9, when the motor coil + OA is fully supplied with current in one direction, a force in the right direction acts on the motor coil, and as shown in ■ in Figure 8, it further moves by ip. It will stop at the specified position. In this way, the ninth
By supplying the entire current in the pattern shown in the figure,
71) The motor coil can be moved by 71). Here, pattern O in FIG. 9 shows that the motor current remains in the previous state and does not change.

This indicates that X of the Holmic signal can be either 1 or 0. The HallMi c signal outputs 1 when it is N pole, and outputs a small OK when it is S pole.

With the above configuration, the movable part of the linear DC motor can be moved to the command value aO position.

〔Effect of the invention〕

According to the present invention, it is possible to drive and control a linear DC motor without an arithmetic circuit for obtaining a deviation signal or an amplifier for supplying current or voltage according to the deviation.
This has the effect of reducing the cost of the groan suppressing device. Further, even if step-out occurs, the position is detected by position detection and the drive is performed until the command value I is reached, so that there is no deterioration in positioning accuracy.

[Brief explanation of the drawing]

FIG. 1 shows the configuration of a shaping device according to an embodiment of the present invention. Figure 2 is a vertical sectional view showing the entire structure of a linear DC motor, Figure 3 is a sectional view taken along line A-A in Figure 2, and Figure 4 is B in Figure 2.
-B sectional view. FIG. 5 is a layout diagram of absolute scales, and FIG. 6 is a layout diagram of absolute scales with unequal intervals. FIG. 7 is a configuration diagram of the current supply device, FIG. 8 is an operation diagram of the motor, FIG. 9 is a mark showing the operation pattern of the current distributor, and FIG. 10 is a diagram showing the current direction of the motor coil. 1...Magnet 2...Movable part 3...Current supply 4...Comparator 5...Scale 5'+5
"... Absolute scale 6... Scale head 7... Motor outer frame 8... Linear guide rail 9... Linear guide slider 10... Coil 20... Hall IC 31... Current distribution 32A, 32B...AND circuit 33...N
OT circuit 34...pulse generator. Condolence 10 r-ttno Now...Koshi I Gushiichi 5'
:'o':3) Koi-shi 108
lυb half group 1 (//l IOj5

Claims (1)

[Claims] By arranging magnets magnetized in the thickness direction and continuously arranging magnetic space groups in a straight line in which the directions of magnetic flux alternately point in opposite directions,
A control device for a linear DC motor including a multi-phase coil movable in the arrangement direction of the magnetic space group arranged in the magnetic space includes a position detector for detecting the position of a movable part of the linear DC motor; a comparator that compares the magnitude relationship between the output value of the device and the command value; and one phase or multiple phases of the multiphase coil of the linear DC motor is selected at an arbitrary cycle, and the selected phase is controlled according to the output signal of the comparator. A control device for a linear DC motor, characterized by comprising a current supply device that supplies current.