JPH04299402A - Motor controller containing position detecting function - Google Patents

Abstract

PURPOSE:To eliminate a need for separately providing a position detector means for the sequence control, etc., which are carried out based on the position information by generating internally the position information on a member which is displaced by the revolution of a motor. CONSTITUTION:A motor controller feeds back the output of an encoder provided in a motor and controls the revolving speed of the motor to the commanded value. Then the motor controller is provided with a position detector means consisting of an arithmetic part 32 which fetches the output of an encoder 5 and produces a position signal, a comparator part 33 which compares the value of the position signal with the set position data, an output part which receives the coincidence signal from the part 33 and performs the rise or fall of the position detecting signal, and a control part 34 which monitors the value of the position signal and its increasing/reducing direction and sends successively the position signal and the next set position data to the part 33.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor speed control device having a built-in position detection function suitable for sequence control based on position information.

0002

[Prior Art] Fig. 4 shows an example of a sequence control device that sequentially operates controlled elements such as electromagnetic valves, lamps, switches, and servo motors in accordance with the position of a moving work head. . In the figure, 1 is a worm gear, 2 is a working head screwed to the worm gear 1, and the worm gear 1 is connected to a servo motor 4 via a reducer 3.
is driven to rotate at a constant speed. The working head 2 moves left and right at a speed determined by the pitch of the worm gear 1 and the forward and reverse rotation speed. Reference numeral 5 denotes a speed control device for the servo motor 4, which has a power section that supplies electric power to the motor 4 and a speed control section, and this speed control section feeds back the output of a pulse encoder 6 that is connected to the servo motor 4. The actual speed of the motor 4 is calculated, and the output of the power section is controlled so that the deviation between this actual speed and the speed command from the sequencer 7 becomes zero. 8A, 8B, and 8C are position sensors (in this example, limit switches) arranged along the axial direction of the worm gear 1, which operate when the work head 2 engages or approaches, and whose position detection signals are sent to the sequencer 7. be taken in. The sequencer 7 sequentially generates command signals to the controlled elements described above based on the position detection signals sequentially transmitted by the position sensors 8A, 8B, and 8C. For example, the sequencer 7 generates a command signal to close the electromagnetic valve based on a position detection signal when the work head 2 moving in the direction of the solid arrow in the figure engages or approaches the position sensor 8B, and the work head 2 closes the electromagnetic valve. A command signal for opening the electromagnetic valve is generated based on a position detection signal when the position sensor 8C is engaged with or close to the position sensor 8C. In addition, position sensors 8A, 8B, 8C
In place of, pulse encoder 9 and electronic limit cam 10
In some cases, a set of .

0003

[Problem to be solved by the invention] In this way, conventionally,
In order to obtain position information to be given to the sequencer 7, multiple position sensors 8A, 8B, 8C and a set of pulse encoder 9 and electronic limit cam 10 are provided, which increases costs accordingly. There was the problem of inviting

The present invention has been made to solve this problem, and is capable of internally generating positional information of members that are displaced as the motor rotates, and is useful for sequence control based on positional information. It is an object of the present invention to provide a motor control device with a built-in position detection function that does not require separate position detection means.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a motor control device that performs feedback control of a motor. A comparison section that compares the value of the signal with the set position data, an output section that receives the coincidence signal sent by this comparison section and raises or lowers the position detection signal, and monitors the value and increase/decrease direction of the position signal. and a control section that sequentially sends the set position data to be compared with the position signal to the comparison section sequentially.

[0006] According to a second aspect of the present invention, the motor is a motor that sequentially moves the working head linearly forward and backward from a set position to a set position, and the position detection signal is an actuation/stopping of a controlled element determined corresponding to the set position. can now be given as position information to the sequencer that controls it.

In claim 3, the position detection means includes a direction discriminator that takes in the output of the pulse encoder and sends out a forward position pulse and a reverse position pulse, and adds the forward position pulse and the reverse position pulse, respectively. /An up/down counter to be subtracted, a comparator to compare the counted value of this up/down counter with set position data, and the above comparator using the set position data to which the counted value that increases or decreases comes closest to as a comparison value. a microcomputer that simultaneously sends out a gate signal; a first gate element and a second gate element that receive a coincidence signal from the comparator and are alternately given the gate signal; and a flip-flop that is set and reset by the output of the second gate element.

[0008]

[Operation] In the present invention, the feedback signal is processed to generate a position signal, and when this position signal is in an increasing direction, the value of the increasing position signal is used as the comparison value of the set position data that approaches the first. sent to. When both sounds are equal and the comparator sends out a matching signal, the gate element gated by the gate signal is turned on, and the output of the flip-flop becomes "H" or "L".

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, a motor control device (servo driver) 10 includes a speed control section 11 and a position detection section 12. The output of the pulse encoder 5 connected to the servo motor 4 is sent to the speed controller 2 as a speed feedback signal.
0, and the position detection unit 3 as a position feedback signal.
Incorporated into 2.

The position detecting section 30 has a configuration shown in FIG. In the figure, reference numeral 31 denotes a direction determining element, which determines the rotation direction of the servo motor 4 from the A-phase and B-phase outputs of the pulse encoder 5, and when it is in the forward rotation direction, the up terminal of the up/down counter 32 If UP is in the reverse direction, a position pulse is input to the down terminal DWN of the up/down counter 15. The count value Nc of the up/down counter 32 is calculated by the comparator 33, and the position data D output from the microcomputer CPU34 is calculated by the comparator 33.
1, D2, and D3. This position data is data set in advance by the data setter 35, and D1<
The relationship is D2<D3. The CPU 34 calculates the count value N
c is taken in, and if the value is increasing, the position data D1, D2, and D3 are sent out sequentially, and when the number of sending out is an odd number, the gate signal S1 is sent out, and when the number of sending out is an even number, the gate signal is sent out. Output S2. 36A is a gate element (AND element) which receives the coincidence signal C sent by the comparator 33 and the gate signal S1 sent by the CPU 34, and when both signals are "H", sets the flip-flop FF37 to a set terminal. "H"
Make it. 36B is a gate element (AND element),
The match signal C sent by the comparator 33 and the gate signal S2 sent out by the CPU 33 are input, and when both signals are "H", the reset terminal of the flip-flop F/F20 is set to "H".

Next, the operation of this device will be explained with reference to FIG.

It is now assumed that the servo motor 4 starts rotating forward and the work head 2 starts moving from the reference position D0 (<D1) toward the position D1. At this time, the count value Nc of the up/down counter 32 satisfies Nc<D1 and is in the direction of increasing, so the CPU 34 provides the position data D1 as a comparison value to the comparator 33 and also outputs the gate signal S1. Set it to "H". When Nc=D1 and the comparator 33 generates the coincidence signal C, the AND element 36
The output of A becomes "H", the F/F 37 becomes "H", and the position detection signal P rises. When Nc<D1, CP
U34 sets the gate signal S1 to "L" and sets the gate signal S2 to "H", and since D1<Nc<D2,
The position data D2 is given to the comparator 33 as a comparison value. N
When c=D2 and the comparator 33 generates the coincidence signal C, the AND element 36 becomes "H" and the F.F37
The output becomes "L" and the position detection signal P falls.

On the other hand, when the operating head 2 returns from the position D3 in the direction of the dashed arrow, the CPU 34 does not output the position data D1, D2, and D3 because Nc decreases.

In this way, in this embodiment, the position detection section 3
0 performs the functions of the conventional position sensors 8A to 8C, pulse encoder 9, electronic limit cam 10, and can be newly installed by simply incorporating an electronic circuit into the motor control device or adding a part of the program. Therefore, when used for sequence control based on position information, it is extremely effective in terms of cost, maintenance, space, etc.

[0016]

As described above, the present invention processes a feedback signal to generate a position signal in a motor control device that performs feedback control, and when the value matches set position data, generates a position detection signal. By providing a means for causing or extinguishing an object, there is no need to provide a separate position detection means to detect the position of an object moved by a motor, which reduces costs compared to conventional methods. In addition, it is possible to save space and maintenance by eliminating the trouble of arranging a separate position detection means.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a position detection section in the above embodiment.

FIG. 3 is a time chart for explaining the operation of the above embodiment.

FIG. 4 is a block diagram of a conventional sequence control device.

[Explanation of symbols]

1 Worm gear 2 Work head 4 Motor 5 Pulse encoder 30 Position control section 31 Direction discriminator 32 Up/down counter 33 Comparator 34 CPU 35 Data setting device 36A, 36B Gate element 37 Flip-flop

Claims (3)

[Claims] 1. A motor control device that controls the speed of the motor to a speed command value by feeding back the output of an encoder provided in the motor, comprising: a calculation unit that takes in the output of the encoder and generates a position signal; A comparison section that compares the value of the signal with the set position data, an output section that receives the coincidence signal sent by this comparison section and raises or lowers the position detection signal, and monitors the value and increase/decrease direction of the position signal. A motor control device with a built-in position detection function, characterized in that a position detection means is provided, comprising a control section that sequentially sends out the set position data to be next compared with the position signal to the comparison section. [Claim 2] The motor is a motor that moves the work head linearly forward and backward sequentially from set position to set position, and the position detection signal controls activation/stopping of a controlled element determined corresponding to the set position. 2. The motor control device with a built-in position detection function according to claim 1, wherein the motor control device is provided as position information to a sequencer. 3. The position detection means includes a direction discriminator that takes in the output of the pulse encoder and sends out a forward position pulse and a reverse position pulse, and adds/subtracts the forward position pulse and the reverse position pulse, respectively. An up/down counter, a comparator that compares the count value of this up/down counter with set position data, and the set position data where the count value that increases or decreases comes closest to being sent to the comparator as a comparison value. a microcomputer that simultaneously sends out a gate switching signal; a first gate element and a second gate element that input a coincidence signal from the comparator and are alternately switched by the gate switching signal;
3. The motor control device with a built-in position detection function according to claim 1, further comprising a gate element and a flip-flop which is set and reset by the output of the second gate element.