JP2890313B2 - Linear actuator and control method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a linear actuator, particularly to a linear actuator used in an automatic assembling apparatus and the like, and a control method thereof.

(Prior Art) FIG. 6 (a) shows a conventional linear actuator, which is provided with a driving motor 2 having an encoder 3 at one end of a frame 1 and coupled to a shaft of the motor 2. 4 and a carriage 6 is engaged with the screw 5 so that the electric motor 2
Is converted into a linear motion of the carriage 6.

In the frame 1, an area switch 7 for generating a signal for defining an area corresponding to a Z-phase signal from the encoder 3 for determining the operation origin of the carriage 6, a lower limit switch 8 and an upper limit switch 9 for limiting the operation range of the carriage 6 Is provided, and the position of the carriage 6 is controlled by rotating the electric motor 2 under the control of the control device 10 shown in FIG. 6 (b).

In the control device 10, reference numeral 11 denotes a commanding unit, a teaching box provided with an indicator light, a switch, and the like indicating an operation state of each unit of the control device; 12, a signal processing unit including a microcomputer; An amplifier that is controlled by the output of the signal processing unit and supplies electric power to the electric motor 2.

In the figure, an electric motor 2, an encoder 3, an area switch 7, a lower limit switch 8, an upper limit switch 9
Is provided in the drive mechanism, and the other part is provided in the control device 10, and detects the speed and position of the carriage 6 by the output of the encoder 3 coupled to the rotating shaft of the electric motor 2 provided in the drive mechanism. It is configured as follows.

That is, a signal such as a moving direction and a moving amount of the carriage 6 is instructed from the teaching box 11 to the signal processing unit 12, and the electric motor 2 is rotated by the electric power output from the amplifier 13 in accordance with the output of the signal processing unit 12 to move the carriage 6 in a predetermined direction. The output of the encoder 3 is input to the signal processing unit 12 and compared with a command value, and the motor is stopped at a position that matches the command value.

Here, the output of the encoder 3 indicating the amount of movement of the carriage 6 includes the A and B phases in which N ₀ pulses are generated during one rotation of the rotor of the encoder 3 and the Z phase in which one pulse is generated per rotation. , And the number of pulses N indicating the entire movement amount can be expressed as N = R + N ₀ .Z. Here, R is the number of pulses less than one rotation.

That is, the sum of R, which indicates the number of pulses of less than one rotation, and the product of Z, which indicates the number of rotations, and N _{0 is} the number of pulses, which indicates the entire movement amount.

Here, the Z-phase pulse is called the home pulse of the encoder.
An important signal in the position control system.
Must be set so as to have a certain relationship with the origin of the operation.

In the illustrated device, a Z-phase signal is generated from the encoder 3 during one rotation in the direction of the lower limit switch 8 after the operation of the area switch 7 and the counter of the signal processing unit 12 is reset.

Upper limit switch 9 and lower limit switch 8
Is a safety device when the motor drives the carriage 6 beyond the control range. When this switch is operated, the motor is stopped by means such as zeroing the output pulse regardless of the command value of the microcomputer. .

Alternatively, instead of a mechanical or electrical switch such as an upper limit switch, the value of the operable range is fixedly set in advance as a software limit. Or both are used together.

(Problems to be Solved by the Invention) Hereinafter, the principle of setting the origin position and its problems will be described with reference to FIG.

In the figure, (+) indicates the upper limit direction, (-) indicates the lower limit direction,
(M) is an electric motor, 7 is an area switch, 7a and 7b are actual operating points of the area switch, and Za and Zb are positions where a Z-phase signal of the encoder is generated.

In general, it is known that the operating point of a control switch used for an area switch or the like varies. That is, the operation of the area switch 7 varies and its operating point 7a
And between 7b. When a Z-phase signal is generated between the operating points 7a and 7b, there arises a problem that the set position of the origin shifts as described below.

When the motor (M) is rotated in the (-) direction to perform the operation of setting the origin, the area switch operates at the operating point 7a due to the above-mentioned variation, and the area corresponding to the Z-phase signal is obtained from this position. It is assumed that an area signal that determines From this point, the motor is rotated once in the same direction in the above-mentioned area. When the motor reaches point B, the motor is stopped. Then, when the motor is reversed, a Z-phase signal of the encoder is generated at point Za. The counter of the signal processing unit 12 is reset by an AND signal of the Z-phase signal and the area signal, and the counter value is read by making another rotation in the same direction in order to cancel backlash or the like of the mechanical unit, and the motor is turned on ( The counter is rotated by the same value as the reading of the counter in the-) direction and stopped, and this position is stored in the memory of the signal processing circuit as the origin set position Ga.

However, due to the variation in the operation of the area switch,
The area switch operates at the position 7b, and an area signal that determines the area corresponding to the Z-phase signal may be generated from this position. In this case, B 'which has made one rotation in the (-) direction from point 7b
When the motor (M) is stopped at this point and reversed from this position, the Z-phase signal of the encoder is generated at the position of Zb, the counter of the signal processing unit 12 is reset, and the position of Zb is rotated one turn from the position of Za. Since the position is shifted in the (-) direction, if the origin is set in the same operation thereafter, the origin position is set to Gb shifted by one rotation.

That is, as shown in FIG. 7, when the area switch 7 is set to a position where the Z-phase signal is generated across the operating points 7a and 7b of the area switch 7 that generates the area signal, the origin is set at one rotation. The problem of displacement occurs.

Therefore, since the setting of the position of the area switch requires a high degree of skill, the setting position of the area switch 7 for determining the area start position is predetermined when the device is manufactured, and the area switch is set so that the user cannot move. It has become. Therefore, as shown in FIG. 8, even when the operation area extends far from the origin, it is necessary to always start from the origin, so that the cycle time becomes longer, and the software limit that defines the upper limit of the substantial operation range is fixed. Since the operation area of the carriage cannot be easily changed because the setting is made in an appropriate manner, there is an inconvenience that other peripheral devices cannot be arranged within the operation area predetermined by setting the upper and lower limit switches. Was.

Further, since the area switch and the upper limit switch and the lower limit switch are provided in advance, the operation area of the actuator cannot be reversed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a linear actuator and a control method thereof, in which the setting positions of the area switch and the upper limit switch can be easily changed.

(Means for Solving the Problems) In a linear actuator according to the present invention, a movable portion, a fixed portion slidably engaged with the movable portion, and relative movement between the movable portion and the fixed portion are generated. Actuator that generates a Z-phase signal that determines the origin of relative movement between the movable part and the fixed part, and generates a signal that defines an area corresponding to the Z-phase signal. An area switch and a switch that generates a signal indicating an upper limit and a lower limit of the relative movement, respectively, are disposed on the movable unit, and an actuator for operating the switch is disposed on the fixed unit. In addition, an origin marker is provided, in which a band in which the setting of the area switch is allowed and a band in which the setting of the area switch is not allowed are alternately displayed.

The actuator provided on the fixed part includes a mounting base for the operator, a stopper part for preventing the movement of the movable part, and an operation piece for operating the switch, and is provided on a longitudinal side surface of the fixed part. The mounting table is slidably inserted into the groove and fixed.

In the linear actuator according to the present invention, along the groove provided on the side surface of the fixed portion, a band that allows setting of the area switch and a band that does not allow setting of the area switch are alternately displayed. A marker plate can be provided.

The method for controlling a linear actuator according to the present invention includes a movable part, a fixed part slidably engaged with the movable part, an electric motor for causing relative movement between the movable part and the fixed part, An encoder that generates a Z-phase signal that determines the origin of the relative movement between the movable part and the fixed part; an area switch that is disposed on the movable part and that generates a signal that defines an area corresponding to the Z-phase signal; A switch for generating a signal indicating the upper limit and the lower limit of the relative movement, respectively, and an actuator for operating the switch, which is disposed on the fixed portion,
Activating the switch, which is provided on the fixed portion, an origin marker in which a band allowing the setting of the area switch and a band not permitting the setting of the area switch are alternately displayed, and the switch set on the fixed portion. An operation device for controlling the motor, a control device for the electric motor, the control device sending a command to the microcomputer, a signal light for displaying a state of each part, a control switch, and a device for displaying a moving amount of the movable part. A teaching box with an absolute value counter that operates on the output of the encoder, an amplifier that compares the output of the microcomputer and the output of the encoder, and converts the deviation into control power for the motor, A configuration in which signals of the area switch and upper and lower switches provided in the movable unit are input to the microcomputer, respectively. A method for controlling a linear actuator, comprising: fixing an actuator of the area switch within a permissible band of the area switch of the origin marker; Is rotated in the lower limit direction to stop the motor by the operation of the area switch, (b) the motor is rotated once in the same direction to stop the motor, and (c) the motor is rotated in the reverse direction to output a signal of the area switch. The absolute value counter is reset by an AND signal with the Z-phase signal from the encoder, and when the encoder reaches a value of one rotation or more, the counter is read and the motor is stopped. (D) The motor is read by the counter The motor is stopped only after the reverse rotation, and this point is determined as the origin.

In the method for controlling a linear actuator according to the present invention, the microcomputer further includes a software limit switch for independently stopping the motor, and (a) the origin is set by a second program stored in the microcomputer in advance. After confirming the completion, the value (A) corresponding to a preset distance from the origin in the direction of the lower limit switch is stored in the RAM, and (b) the motor is rotated in the direction of the upper limit switch, and the operation of the upper limit switch is performed. Then, the motor is stopped, and the value of the absolute value counter is read. (C) A preset value is subtracted from the reading of the absolute value counter, and the difference value (C) is obtained.
Is stored in the RAM, and the positions (A) and (C) stored in the RAM can be set as the setting positions of the software limit switches.

(Operation) In the linear actuator and the control method thereof according to the present invention, a new origin is set by setting the area switch to a band allowing the setting of the area switch formed on the origin marker along the position where the operator of the frame is set. Becomes possible.

Further, the setting of the software limit switch corresponding to the new area and the setting position of the upper and lower limit switches is automatically performed.

Further, the operation area of the actuator can be easily inverted.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIGS. 1 (a) to 1 (c), a drive unit 20 having an electric motor is slidably engaged with the frame 1. The drive unit 20 has a region switch 22 and a lower limit switch 23. And an upper limit switch 24. The frame 1 is provided with operators 30 and 40 and an origin marker plate 15.

On the side surface of the frame 1, a T-shaped groove 14 is provided in the longitudinal direction thereof, and an origin marker plate 15 for facilitating the setting of the area switch 22 is located along the T-shaped groove 14,
The actuator 30 has a mounting table 31, a stopper 32, and a moving piece 33.
The mounting base 31 is inserted into a T-shaped groove 14 provided in the frame 1 and can be fixed to the frame 1 at an arbitrary position by a mounting screw 34.

The operation element 40 has the same structure as the operation element 30. First
FIG. 3C shows a state in which an actuator is mounted in the T-shaped groove of the frame 1, and the operating piece 33 has such a size that its tip protrudes from the outside of the T-shaped groove 14.

The area switch 22 and the lower and upper limit switches 23 and 24 provided in the drive unit 20 are U-shaped photoelectric contactless switches, and an actuator 30 provided on the frame 1 in a light path of the contactless switch. When the operation piece 33 enters and cuts off the light, it has a known structure in which an output is output from the non-contact switch,
The interval between the lower limit switch 23 and the area switch 22 and the interval between the lower limit switch 23 and the upper limit switch 24 are provided at the same interval.

Hereinafter, the principle of the origin marker plate 15 provided to facilitate the setting of the area switch 22 will be described.

As a result of various experiments, the present inventor has found that, as shown in FIG. 7, there is a chance that the area switch is set at a position where the Z-phase signal of the encoder is generated within the range of variation of the operating point of the area switch. As shown in ()), it has been found that it appears repeatedly with one rotation of the encoder connected to the motor of the drive unit 20 as a cycle.

The variation of the operating point of the area switch 7 is 7a-
Since it is within the range of 7b, the position outside this range is not affected by the variation of the area switch 7. Therefore, FIG. 1 (d)
The band in which the setting of the area switch 7 is prohibited as shown in FIG.
The band of B is generated repeatedly with one rotation of the encoder as a cycle, and the band of A excluding B in one rotation is the range of variation of the operating point when the area switch is set in this band. Since no Z-phase signal is generated within the range, the band is set to allow setting of the area switch.

Accordingly, in the present invention, the origin marker plate 15 is provided with a band A in which the setting of the area switch 22 and a band B in which the setting is prohibited in the longitudinal direction alternately, as shown in FIG. Is displayed continuously.

FIG. 3 (a) shows a control system for a linear actuator according to the present invention. Reference numeral 50 denotes a device or a switch for giving a command to a control device or displaying a moving amount of an indicator light driving portion indicating an operation state of each portion. A teaching box provided, 60 is a microcomputer control unit, 61 is a ROM, 62 is a CPU, 63 is a RAM, 70 is a counter indicating an absolute position, 71 is an AND circuit, 72 is an adder, 73
Is a deviation counter, 80 is an amplifier, 81 is a position control unit, 82 is a speed control unit, 83 is a power amplifier, 90 is a motor for driving the drive unit 20, and 91 is an encoder connected to the motor 90.

The motor 90, the encoder 91, the area switch 22, the lower limit switch 23, and the upper limit switch 24
The other parts are arranged in the control box.

Next, a procedure for determining the position where the origin marker plate 15 is fixed to the frame 1 will be described.

(1) When the actuator 30 is moved to activate the area switch 22, the indicator light provided in the control device is turned on.

(2) From this position, the motor is rotated once in the (-) direction by a manual switch provided on the teaching box to stop the motor, and when the motor is reversed and rotated in the (+) direction, the Z-phase signal of the encoder 91 is rotated within one rotation. Then, the absolute value counter 70 is reset by this Z-phase signal, further rotated about one turn (+), stopped, and the value of the absolute value counter 70 was read.
When the motor is rotated in the reverse direction and then stopped by rotating the same value as the reading of the absolute value counter 70, the origin is set.

(3) Reset the device for displaying the amount of movement of the drive unit for counting encoder pulses provided in the teaching box 50, and rotate the motor in the (+) direction with a manual switch to return the area switch 22 to display. Confirm that the light goes off and stop the motor.

(4) The motor is rotated in the (-) direction by the manual switch, and the motor is stopped at the moment when the indicator light is turned on. The value on the display device is read, and this value corresponds to the number of pulses of 1/2 rotation of the encoder. By repeatedly adjusting the position of the actuator 30 so as to obtain a predetermined value, the operator 30 is fixed to the frame at a position where the reading of the display device has reached a predetermined value, and as shown in FIG. The origin marker plate 15 is fixed to the frame 1 by aligning the right end of the operation piece 33 with the approximate center position of the band A where the setting of the area switch of the origin marker plate 15 is permitted.

Thereafter, the actuator 30 provided on the frame 1 is moved to the vicinity of the required origin setting position, and the position is set so that the right end of the operation piece 33 is within the origin setting allowable band A of the origin marker plate 15. Adjust and fix with screws.

The rotating shaft of the electric motor 90 provided in the driving unit 20 is configured to function to cause relative movement between the driving unit 20 and the frame 1 via an engagement device, and the rotating shaft of the electric motor 90 is Is configured to detect the relative position and speed between the drive unit 20 and the frame 1 based on the output of the encoder 91 coupled to the drive unit 20.

That is, the A and B phase outputs 92 of the encoder 91 are input to one terminal of the adder 72, and the current position signal of the drive unit 20 is input to the microcomputer control unit 60 via the absolute value counter 70, and the command value is The calculated value is compared with the command value of the microcomputer control unit 60 input to the other terminal of the adder 72 in the adder 72, and the output is output from the deviation counter 73 via the deviation counter 73 and the amplifier 80. When the relative position between the drive unit 20 and the frame 1 reaches the amount of movement specified by the microcomputer control unit 60, the drive unit
Movement of 20 stops.

A part of the A and B phase outputs of the encoder 91 is converted into a signal proportional to the speed of the motor 90, and is fed back to the speed control unit 82 of the amplifier to stabilize the speed of the motor 90.

In the control system shown in the figure, a command for the movement amount is given from the teaching box 50 to the microcomputer control unit 60, and the movement amount is calculated in the microcomputer control unit 60 by comparing it with the current position stored in the RAM 63. In response, a movement amount is commanded to drive the electric motor 90.

All the movement amounts are calculated with reference to the origin position, and the operation is started by giving the position of the origin since the command is issued.

The command for setting the origin is stored in the microcomputer control unit 60.
It is stored as a first program in the ROM 61,
The algorithm is started by the command of "set origin" of the teaching box 50, and the algorithm is as shown in FIG. 3 (b). (1) The motor 90 is rotated to drive the drive unit 20 in the (-) direction (FIG. a) to the left) and the actuator 30 operates the area switch 22. As a result, the motor 90 stops and the indicator lamp lights up.

(2) The motor 90 is further rotated once in the same direction and stopped.

(3) The motor 90 is rotated by giving a command to rotate it one or more times in the opposite direction. As a result, the origin switch 22 operates again, and the Z-phase output of the encoder 91 is further generated. Therefore, the Z-phase output is ANDed with the signal of the area switch 22 by the AND circuit 71, and the absolute value counter 70 is output from the output. After resetting, the absolute value counter 70 counts the output of the encoder 91.

(4) The reading of the absolute value counter 70 at the time when the motor 90 stops by rotating one or more times in the reverse direction is stored in the RAM 63.

(5) The motor is rotated again in the (-) direction, and is stopped until it matches the reading of the absolute value counter 70 stored in the RAM 63. This position is the origin of the system.

In this way, the origin is determined and the teaching box
The movement amount instructed from 50 is calculated based on the set origin and instructed to the adder 72, and operates to move the drive unit 20 according to the instruction value.

This origin setting operation is always executed when the position of the area switch 22 is moved, and when the power is turned off, the servo is turned off, so that the output pulse from the encoder 91 cannot be counted. After that, the origin does not change until the power is turned off.

Next, the setting of the software limit switch will be described.

Although the upper and lower limit switches 24 and 23 have been described earlier, this is a safety device when the drive device operates for some reason ignoring the signal from the control device. The motor 90 is stopped by setting the output of the deviation counter to zero irrespective of the signal.

However, since there is a moment of inertia of the motor, the driving device, the frame, and the like, and even if the current of the motor is set to zero, the motor may run eccentrically due to the moment of inertia. A software limit switch is provided for setting the output of the deviation counter to zero and stopping the motor when the value reaches a certain value stored in the irrespective of the microcomputer signal.

In the prior art, the setting position of the software limit switch is written in the ROM, so when the position of the upper limit switch is changed, the contents of the ROM must be rewritten.

In the present invention, as the area switch can be moved, the upper limit switch can be moved. Therefore, it is necessary to reset the position of the software limit switch in relation to the position of the upper limit switch. .

FIGS. 4 (a) and 4 (b) are flowcharts of a procedure for setting a software limit switch, which procedure will be described below.

(B) Check the position of the origin.

(B) Set the mode of the teaching box 50 to the software limit switch teaching mode.

(C) When the start key is pressed, the second key stored in the ROM
Is executed, and the position of the lower limit software limit switch moved by the distance (a) from the origin in the direction of the lower limit switch is stored in the RAM 63.

(D) The motor rotates in the direction of the upper limit switch, the upper limit switch operates, and the motor stops.

(E) At this position, the absolute value counter is read and its value (c)
Further, a certain set value (d) is subtracted, and the result is stored in the RAM as (C).

With the above procedure, the position (A) of the lower limit software limit switch and the position (C) of the upper limit software limit switch are automatically set.

In the second embodiment of the present invention, the origin can be set and the upper and lower limits can be reversed.

That is, in the first embodiment of the present invention, the area switch is arranged at the left end and the upper limit switch is arranged at the right end. However, in the second embodiment of the present invention, the upper limit switch is arranged at the left end and the upper limit switch is arranged at the right end. The origin is set near the right end by setting the area switch.

Therefore, in the second embodiment, unlike the configuration of FIG. 3A, the outputs of the upper limit switch 24 and the area switch 22 are respectively changed via the changeover switch 102 to the AND circuit 71 as shown in FIG. 3D. And the microcomputer controller can be switched and connected. The output signals a and b in the (+) direction and the (-) direction of the encoder can be connected to the (+) side and the (-) side of the adder 72 through the direction discriminating circuit 100. The absolute value counter 70 can be selectively connected to either the (+) side or the (-) side of the absolute value counter 70 via the changeover switch 101 which is linked to the changeover switch 102 while being connected to the terminal.

In the second embodiment, if the changeover switches 101 and 102 are switched in conjunction with each other, the positions of the upper limit switch 24 and the area switch 22 are switched, the upper limit direction is switched to the right and left, and the rotation direction of the output 92 of the encoder is changed. Is switched so that the operation direction of the absolute value counter and the upper and lower limit directions are simultaneously switched.

That is, when the changeover switches 101 and 102 are switched in the (+) direction in FIG.
1 and the upper limit switch 24 is connected to the microcomputer control unit, which is the same as in FIG. 3 (a).

The output of the encoder 91 is connected via the direction discriminating circuit 100 to the (+) direction signal a and the (+) direction signal b as they are, respectively, to the (+) and (-) terminals of the adder 72. ,
This part is also the same as FIG. 3 (a).

On the other hand, the signal a is connected to the (+) side of the absolute value counter 70 and the signal b is connected to the (-) side of the absolute value counter 70 via the changeover switch 101, which is also the same as FIG.

Next, when the changeover switches 101 and 102 are turned on to the (-) side,
The area switch 22 is connected to the microcomputer control unit, the upper limit switch 24 is connected to the AND circuit 71, and the (+) direction signal a of the encoder 91 is supplied to the (−) side of the absolute value counter 70 via the direction discrimination circuit 100. , (−) Direction signal b is connected to the (+) side, respectively, and the upper and lower limits of the operation direction of the drive unit are reversed.

Therefore, the right end in FIG. 1 is the lower limit direction. When the changeover switch is switched to the (-) side as described above, the position of the area switch changes, so it is necessary to set the origin.
For this purpose, the left end of the actuator 40 on the frame is fixed to an arbitrary position in the A band of the origin marker plate 15, and the origin setting operation is automatically performed by the first program stored in the microcomputer control unit by the origin setting command. Do it. In this case, the rotation direction of the electric motor M shown in FIG.
The operation of setting the software limit switch is the same as that of the first embodiment, except that the operation of (−) is changed. The relationship between the upper and lower limits and the origin in FIG. Just works exactly the same.

(Effect of the Invention) Since the linear actuator and the control method thereof according to the present invention are configured as described above, it is easy to change and set the set position of the origin, and it is possible to freely change the operation area of the drive unit. As shown in FIG. 5, it becomes possible to arrange other peripheral devices outside the set positions of the upper and lower limit switches without interfering with each other, thereby increasing the space utilization. There is an effect that can be done.

Also, since the operation origin of the drive unit can be switched to either the left end or the right end of the frame, the position of the origin can be set so that the operation distance of the drive unit becomes the shortest, and the utilization efficiency of the linear actuator is improved. effective.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a region of a linear actuator according to the present invention and a state of mounting upper and lower limit switches, FIG. 1B is a perspective view showing details of a frame and an actuator mounted on the frame, FIG. 1C is a sectional view showing a state in which an actuator is mounted on the frame, FIG. 1D is an explanatory view of a setting band of the area switch, and FIG. FIG. 3 (a) is an explanatory view of a fixed position of an actuator guided by a marker plate, FIG. 3 (a) is a configuration diagram showing a control system of a linear actuator, FIG. 3 (b)
Is a flowchart showing the algorithm for setting the origin,
FIG. 3 (c) is an explanatory diagram of the operation, FIG. 3 (d) is a block diagram of a control system of a linear actuator showing another embodiment of the present invention, and FIG. 4 (a) is an algorithm for setting a software limit switch. FIG. 4 (b) is an explanatory diagram showing the relationship between other limit switches and the origin, FIG. 5 is an explanatory diagram of an operation area of a drive unit in the linear actuator of the present invention, and FIGS. 6 (a) and 6 (a). FIG. 7 (b) is an explanatory view of a configuration of a conventional linear actuator, FIG. 7 is an explanatory view showing a relationship between a setting position of an area switch, a generation position of a Z-phase signal of an encoder, and an origin, and FIG. FIG. 4 is an explanatory diagram of an operation area of FIG. 1 ... frame, 2,90, M ... electric motor, 3,91 ... encoder, 4 ... coupling, 5 ... screw, 6 ... carriage, 7,22 ... area switch, 7a, 7b ... Actual operating point of area switch, 8,23 …… Lower limit switch, 9,24…
… Upper limit switch, 10 …… Control device, 11,50 ……
Teaching box, 12 …… Signal processing unit, 13,80 ……
Amplifier, 14 Groove, 15 Origin marker plate, 20 Drive, 30, 40 Actuator, 31 Mounting base, 32 Stopper, 33 Operation piece, 34 Mounting screw , 60 ... microcomputer control unit, 61 ... ROM, 62 ... CPU, 63 ... RAM, 70
…… Absolute value counter, 71 …… AND circuit, 72 …… Adder, 7
3 Deviation counter, 81 Position control unit, 82 Speed control unit, 83 Power amplifier, 92 Output, 100 Direction discrimination circuit, 101, 102 Changeover switch.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-91707 (JP, A) JP-A-63-228308 (JP, A) JP-A-61-23211 (JP, A) JP-A-1 112816 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05D 3/12 F16H 19/02 F16H 25/20

Claims (8)

(57) [Claims] A movable part; a fixed part slidably engaged with the movable part; a driving means for causing relative movement between the movable part and the fixed part; A linear actuator comprising: an encoder that generates a Z-phase signal that determines an origin of relative movement between fixed parts; an area switch that generates a signal that defines an area corresponding to the Z-phase signal; and an upper limit and a lower limit of the relative movement. And a switch for generating a signal indicating each of the following are arranged on the movable portion, an actuator for operating the switch is arranged on the fixed portion, and a band allowing the setting of the area switch on the fixed portion. A linear marker provided with an origin marker in which bands in which the setting of the area switch is not permitted are alternately displayed. 2. The operation device according to claim 1, wherein the operation member provided on the fixed portion includes a mounting base for the operation member, a stopper portion for preventing the movement of the movable portion, and an operation piece for operating the switch. The linear actuator according to claim 1, wherein the mounting base is slidably inserted into a groove provided on a longitudinal side surface and fixed. 3. An origin marker or an origin marker plate, in which bands allowing setting of an area switch and bands not allowing setting of an area switch are alternately displayed along a groove provided on a side surface of the fixing portion. The linear actuator according to claim 1, wherein the linear actuator is provided. 4. An origin marker plate is mounted along a groove provided on a side surface of the fixing portion, in which a band in which setting of a region switch is permitted and a band in which setting of a region switch is not permitted are displayed alternately. The linear actuator according to claim 1, wherein: 5. The area switch and the lower and upper limit signal generating switches are arranged in one direction in the above order.
The linear actuator according to 1, 2, 3 or 4. 6. A linear actuator according to claim 1, further comprising a switching circuit for switching said area and upper limit signal generation switches to operate as upper limit and area signal generation switches, respectively. 7. A movable part, a fixed part slidably engaged with the movable part, an electric motor for causing relative movement between the movable part and the fixed part, and a movable part and the fixed part. An encoder that generates a Z-phase signal that determines the origin of relative movement between the units; an area switch that is provided in the movable unit and that generates a signal that defines an area corresponding to the Z-phase signal; and an upper limit of the relative movement And a switch for generating a signal indicating the lower limit and a lower limit, respectively, an actuator for operating the switch, which is disposed on the fixed portion, and a band provided for the fixed portion, which allows setting of the area switch, and the area. An origin marker in which bands in which setting of a switch is not allowed are alternately displayed; an actuator set on the fixed portion for operating the switch; and a control device for the electric motor. A teaching box equipped with a computer, a signal light for sending a command to the microcomputer and displaying a state of each part, a control switch, and a device for displaying a moving amount of the movable part, and an absolute value counter operated by an output of the encoder. An amplifier that compares the output of the microcomputer with the output of the encoder and converts the deviation into control power for a motor; and outputs signals from the area switch and upper and lower switches provided in the movable unit to the microcomputer. A method of controlling a linear actuator configured to input to a computer, wherein an operator of the area switch is fixed within a permissible band of an area switch of the origin marker, and a first stored in a microcomputer in advance. By the program, (a) rotate the motor in the lower limit direction and operate the area switch. (B) The motor is stopped by rotating the motor once in the same direction, and (c) The motor is rotated in the reverse direction and the AND signal of the signal of the area switch and the Z-phase signal from the encoder is turned off. Resets the absolute value counter, reads the counter when the encoder reaches a value of one rotation or more, and stops the motor. (D) Stops the motor after rotating the motor reversely by the reading amount of the counter. A method of controlling a linear actuator, characterized in that at least this point is determined as the origin. 8. A microcomputer further comprising a software limit switch for independently stopping the motor, and a second program stored in the microcomputer in advance to: (a) confirm that the setting of the origin is completed; A value (A) corresponding to a distance set in advance in the direction of the lower limit switch is stored in the RAM. (B) The motor is rotated in the direction of the upper limit switch, and the motor is stopped by the operation of the upper limit switch. (C) subtracting a preset value from the reading of the absolute value counter, storing the difference value (C) in the RAM, and storing the difference values (A) and (C) in the RAM. 8. The control method for a linear actuator according to claim 7, wherein the position of C) is set as the position of the software limit switch.