JP3206355B2 - Linear motor speed correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor speed correcting device, and more particularly, to a linear motor speed correcting device that detects a speed and a position of a mover by using a plurality of magnetic detection sensors to control the speed. Things.

[0002]

2. Description of the Related Art Conventionally, linear motors have been used for opening and closing automatic doors, article transporting devices, and the like. FIG. 8 schematically shows the structure of a conventional three-phase brushless DC linear motor. This three-phase brushless DC linear motor has a length of 24 mm in the stator rail 40 along the longitudinal direction.
Are arranged in plural. The mover 30 is arranged in the stator rail 40. Mover 3
0 is provided with mover coils 32a, 32b, 32c, and these mover coils 32a, 32b, 32c are star-connected. The mover 30 is provided with Hall IC magnetic detection sensors 34a, 34b, 34c. The pitch of the magnetic detection sensors 34a to 34c is set to 8 mm, which is 1/3 of the permanent magnet 48. I have.

Here, a control circuit 150 of a conventional linear motor 20 and its operation will be described with reference to FIGS. 9, 10 and 11. FIG. The Hall IC 34A is shown in FIG.
As shown in (1), the magnetic flux density A1 of the permanent magnet 48 that changes in a sinusoidal manner is detected, and a rectangular output signal B1 is output in response to the magnetic flux density exceeding the threshold value θ1. FIG. 11 shows output signals B1, B of the Hall ICs 34A, 34B, 34C.
2 and B3. The pulse generator 164 of the control circuit 150 shown in FIG. 9 captures the rising and falling edges of the waveforms of the output signals B1, B2, and B3, and generates a pulse P.
1 to P7 are generated. The position counter 152 indicates that the
Output signals B1, B2, B3 of C34A, 34B, 34C
And pulses P1 to P7 are input, and output signals B1, B
The position of the mover 30 is detected by counting up and counting down the number of pulse inputs by 2 and B3. On the other hand, the speed detector 158 is connected to each magnetic detection sensor 3.
The interval (8 mm) between 4a, 34b and 34c is set to each pulse P1 to
The speed is calculated by dividing by the generation interval time of P7. The CPU 155 controls the motor driving transistor 163 based on the position detected by the position counter 152 and the speed detected by the speed detector 158 to selectively energize the mover coils 32a, 32b, and 32c of the mover 30. This controls the linear motor.

[0004]

A linear motor is suitably used as an automatic door engine for interiors of hospitals, offices and the like, and a linear motor capable of opening and closing even heavier doors is required. The present inventor has produced a linear motor capable of opening and closing a 100 kg door, which is twice as heavy as the conventional one, in order to respond to such a request. However, this high-thrust linear motor generates vibrations at a constant speed drive, and not only cannot perform smooth opening / closing operation, but also generates relatively large rattling sound.

[0005] Then, when the speed of the door was measured to find out the cause, it was found that the speed was periodically fluctuated as if the door was driven at a constant speed as shown in FIG. Further, upon examining the measurement results, it was found that this speed change occurred at a pitch of 8 mm.

[0006] From the above results, the present inventors have found that the vibration during the constant speed operation is due to the following reasons. As shown in FIG. 10, the Hall ICs 34A and 34A
B and 34C detect the magnetic flux density A1 (magnetism) of the permanent magnet 48 that changes sinusoidally, and output square-wave output signals B1 and B1.
2 and B3 are generated. Here, the Hall ICs 34A, 34
B, 34C, the magnetic detecting elements 34a, 34b, 34c
In order to invert the output polarity, it is necessary to exceed a certain threshold value θ1. Therefore, after a certain delay time from the timing t1 when the polarity of the magnetic flux switches from the S side to the N side,
The output signal B1 at timing t2 when the threshold value θ1 is exceeded
Stand up. On the other hand, at timing t3 when the magnetic flux density A1 falls below the threshold value θ1, the output signal B1 falls,
Thereafter, at timing t4, the polarity of the magnetic flux switches from the N side to the S side. That is, the output signal B1 rises with a delay from the time when the polarity of the magnetic flux switches from the S side to the N side, and conversely, the output signal B1 falls earlier than when the polarity of the magnetic flux switches from the N side to the S side. .

Here, as shown in FIG. 11, the pulse generator 164 generates pulses P1 to P7 by capturing the rising and falling of the output signals B1, B2, B3 of the Hall ICs 34A, 34B, 34C. I have. Hall IC
A pulse P3 that captures the rising edge of 34C and a hole I
The interval between the pulse P4 that has captured the fall of C34A and the pulse P4 is short because the pulse P3 is delayed and the pulse P4 is advanced. Therefore, when the speed is calculated based on the timing of the pulses P3 and P4, the calculated speed becomes faster than the actual speed. On the other hand, the interval between the pulse P6 capturing the fall of the Hall IC 34C and the pulse P7 capturing the rise of the Hall IC 34A is such that the pulse P6 advances and the pulse P7
Is longer because it is late. Therefore, the pulses P6, P7
When the speed is calculated based on the timing, the calculated speed becomes lower than the actual speed. That is, since the control is performed such that the speed becomes constant based on the calculated speed having the error, it has been found that the speed unevenness described above with reference to FIG. 12 has occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to accurately grasp the speed of a mover and to control the speed of a linear motor which enables precise speed control. A correction device is provided.

[0009]

In order to achieve the above object, a linear motor speed compensating device according to claim 1 is provided with a mover 30, a stator rail 40, and a mover 30 or a stator rail 40. a plurality of magnetic detection sensor 32a that detects the magnetism of magnet array 48 which is set, 32b, 32c and, magnetic detection sensor 32a, 32b, braking you drive the mover 30 based on 32c signals on the stator rail 40 A plurality of magnetic detection sensors 32a, 32b, 3
Rising and falling edge of the signal 2c is outputted
And pulse generating means 64 for generating a pulse with di, the Pal
Speed calculating means 58 for calculating the speed of the mover 30 based on the source signal 64, and the plurality of magnetic detection sensors 32a, 32
b, 32c, based on the output state of the magnetic detection sensor.
Caused by a sensitivity, a plurality of magnetic sensor output
To the rising and falling magnet rows 48
Estimating the deviation of the timing of, the compensation means 59 that the speed calculating means is correct complement the rate at which <br/> calculated and having a.

According to a second aspect of the present invention, in the linear motor speed correcting apparatus according to the first aspect, the detecting means 59 determines a plurality of the plurality of magnetic detection sensors 32a, 32b, and 32c based on a combination of output states. The magnetic detection sensor 32a,
A falling P4 following a rising P3 of the outputs of 32b and 32c is detected, and the speed correcting means 59 calculates the speed calculated by the speed calculating means 58 based on the detection of the falling P4 by the detecting means 59. Correct so that it is slow.

Further, in the linear motor speed correcting device according to the third aspect, in the first aspect, the detecting means 59 determines a plurality of magnetic detection sensors 32a, 32b, and 32c based on a combination of output states. The magnetic detection sensor 32a,
The rising edge P7 following the falling edge P6 of the outputs of 32b and 32c is detected, and the speed correction means 59 calculates the speed calculated by the speed calculation means 58 based on the detection of the rising P7 by the detection means 59. Correct so that

According to a fourth aspect of the present invention, there is provided a linear motor speed compensating apparatus comprising: a mover, a stator rail, and a magnet array provided on the mover or the stator rail; A plurality of magnetic detection sensors 32a, 32b, 32c for detecting the magnetism of
And a control circuit 50 for sending an output for driving the mover 30 onto the stator rail 40 based on the signals of the magnetic sensors 32a, 32b, 32c.
speed calculating means 58 for calculating the speed of the mover 30 based on the rising and falling timings of the output from c.
And the plurality of magnetic detection sensors 32a, 32b, 32c
Position calculating means 52 for calculating the position of the mover 30 based on the output of the magnetic sensor 32, and rising or falling of the outputs of the plurality of magnetic detection sensors 32a, 32b, 32c based on the position calculated by the position calculating means 52. Detecting means 59 for detecting a position where the timing is shifted, and the speed calculating means 58
And a speed correcting means 59 for correcting the speed calculated by the above based on the detection of the deviation of the detecting means 59.

According to a fifth aspect of the present invention, in the linear motor speed correcting apparatus according to the fourth aspect, the detecting means 59 determines a plurality of magnetic detection sensors 32a, 32b based on the position calculated by the position calculating means 52. , 32c, the falling P4 following the rising P3 of the output is detected, and the speed correcting means 59 slows down the speed calculated by the speed calculating means 58 based on the detection of the falling P4 by the detecting means 59. Correct so that

Further, according to a sixth aspect of the present invention, in the linear motor speed correcting apparatus according to the fourth aspect, the detecting means 59 detects a plurality of magnetic sensors 32a, 32b based on the position calculated by the position calculating means 52. , 32c, the rising P7 following the falling P6 of the output is detected, and the speed correcting means 59 increases the speed calculated by the speed calculating means 58 based on the detection of the rising P7 by the detecting means 59. Correction as follows.

Further, in a linear motor speed correcting device according to a seventh aspect of the present invention, in the first to sixth aspects, the magnetic detection sensors include three magnetic detection sensors 32a, 32b, and 32c.

[0016]

In the linear motor speed correcting device according to the first aspect,
The speed calculating means 58 includes a plurality of magnetic detection sensors 32a, 3
The speed is detected based on the rising and falling timings of the outputs from 2b and 32c. Start the output,
When falling, the magnetic detection sensors 32a, 32b, 32
c needs to exceed a certain magnetic flux density θ1. Accordingly, as shown in FIG. 10, the rise t2 is delayed from the original timing t1, while the fall t3 is advanced than the original timing t4. For this reason, when the speed is calculated based on the rising and falling timings (signal period), when the falling signal follows the rising signal, the period between the two signals becomes shorter, and conversely, the rising signal following the falling signal In the case of, the period between both signals becomes long, and the calculated speed does not become a correct value. For this reason, the detection means 59 is provided with the plurality of magnetic detection sensors 32a, 3
The output states of the magnetic detection sensors 2b and 32c are monitored, and points at which the rising and falling timings deviate from the outputs of the plurality of magnetic detection sensors 32a, 32b and 32c are detected. And
The speed correcting means 59 corrects the speed calculated by the speed calculating means 58 based on the detection of the deviation of the detecting means 59.

In the linear motor speed correcting device according to the second aspect, at the time of falling P4 following the rising P3, the period of the signal is shortened and the calculated speed is increased. For this reason, the detection means 59 is provided with the plurality of magnetic detection sensors 32a, 3
Based on the output states of 2b and 32c, a falling P4 following a rising P3 is detected, and the speed correction means 59
Corrects the speed calculated by the speed calculating means 58 so as to be slower.

In the linear motor speed correcting device according to the third aspect, at the rising edge P7 following the falling edge P6, the signal period becomes longer and the calculated speed becomes slower. For this reason, the detection means 59 is provided with the plurality of magnetic detection sensors 32a, 3
Based on the output states of 2b and 32c, rising P7 following falling P6 is detected, and the speed correction means 59
Corrects the speed calculated by the speed calculating means 58 so as to be faster.

In the linear motor speed correcting device according to a fourth aspect, the speed calculating means 58 includes a plurality of magnetic detection sensors 32.
The speed is detected based on the rising and falling timings (signal periods) of the outputs from a, 32b, and 32c. At this time, in the case of the falling signal following the rising signal, the period between both signals is short, and conversely, in the case of the rising signal following the falling signal, the period between both signals is long, and the calculated speed is The value is not correct. For this reason, the position calculation means 52 is provided with the plurality of magnetic detection sensors 32.
The position of the mover 30 is calculated based on the outputs of the magnetic sensors a, 32b, and 32c, and the detecting means 59 calculates the rise and fall of the outputs of the plurality of magnetic detection sensors 32a, 32b, and 32c based on the calculated positions. Is detected. Then, the speed correction means 59
Is corrected based on the detection of the displacement of the detection means 59.

In the linear motor speed correcting device according to the fifth aspect, at the time of falling P4 following the rising P3, the period of the signal is shortened, and the calculated speed is increased. For this reason, the detecting means 59 detects the falling P4 following the rising P3 based on the position calculated by the position calculating means 52, and the speed correcting means 59 calculates the speed calculated by the speed calculating means 58. Is corrected to be slow.

In the linear motor speed correcting device according to the sixth aspect, at the rising edge P7 following the falling edge P6, the signal period becomes longer and the calculated speed becomes slower. For this reason, the detecting means 59 detects the rising P7 following the falling P6 based on the position calculated by the position calculating means 52, and the speed correcting means 59 determines the speed calculated by the speed calculating means 58. Is corrected to be faster.

In the linear motor speed correcting device of the present invention, since three magnetic detection sensors 32a, 32b and 32c are used, the magnetic detection sensors 32a, 32b and 32c are used.
From the combination of the outputs (e.g., ON, ON, ON) of the plurality of magnetic detection sensors 32a, 32b, 3
The timing or position at which the rise and fall of the output of 2c deviate can be easily detected.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. First, the mechanical configuration of the brushless DC linear motor according to the first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 2 is a perspective view of a mover 30 including a coil unit 32 constituting the brushless DC linear motor 20 according to the first embodiment and a sensor unit 34 integrally attached to the coil unit 32. The coil unit 32 incorporates three mover coils 32a, 32b, 32c of the same shape. The sensor unit 34 incorporates three magnetic detection sensors 34a, 34b, and 34c of the Hall IC. Then, each of the mover coils 32a, 32b, 32
c, a power supply line for supplying power to
The signal lines a, 34b, and 34c are connected to a control circuit 50 described later using a power line (not shown).

FIG. 3 shows a cross section of the brushless DC linear motor 20. The mover 30 is movably mounted on a traveling portion 40 ′ of a stator rail 40 formed by an outer rail 42 and an inner rail 44, and constitutes a coil movable type three-phase brushless DC linear motor 20. ing. A permanent magnet 4 having the same length is provided between the outer rail 42 and the inner rail 44 with a yoke 46 interposed therebetween.
A magnet body 49 in which a plurality of 8, 48 are arranged in the longitudinal direction is arranged. The permanent magnets 48, 48 have opposite polarities in the longitudinally adjacent one and the opposite one, and form a uniform magnetic field between the facing permanent magnets 48, 48.

FIG. 1 shows a control circuit 50 for using the brushless DC linear motor 20 of the first embodiment for opening and closing an automatic door. Here, the control circuit 50 is composed of a CPU (not shown) and a memory, and controls the main control unit 5.
5, a current generator 63 composed of a plurality of transistors, and a pulse generator 64 that generates a pulse based on output signals input from the Hall ICs 34A, 34B, and 34C. Control unit 55
Are represented by blocks 56 to 61.

The human body detection sensor 54 is constituted by an infrared sensor for detecting a human body or the like without connection, a touch sensor, a mat switch, or the like.
A detection signal is sent to the 0 side. In response, the main control unit 55
Performs an arithmetic process to be described later to drive the mover 30, and the transistors TRa, TRb, T
Rc, TRa ', TRb', TRc 'are energized to selectively energize the mover coils 32a, 32b, 32c of the mover 30 to drive the mover 30.

As the mover 30 moves, the magnetic detection sensors 34a, 34b, 34c detect the magnetic flux density of the permanent magnet 48 attached to the stator rail 40 side. This operation will be described with reference to FIG. Hall IC34
A detects the sinusoidally changing magnetic flux density A1 of the permanent magnet 48 as shown in FIG. 10, and outputs a rectangular output signal B1 in response to the magnetic flux density exceeding the threshold value θ1. Here, the magnetic detection elements 34a, 34b, 34c of the Hall ICs 34A, 34B, 34C need to exceed a certain threshold value θ1 in order to invert the output polarity. For this reason,
Timing t when the polarity of the magnetic flux switches from the S side to the N side
After a certain delay time from 1, the output signal B1 rises at a timing t2 that exceeds the threshold value θ1. On the other hand, at timing t3 when the magnetic flux density A1 falls below the threshold value θ1, the output signal B1 falls, and thereafter, at timing t4, the polarity of the magnetic flux switches from N side to S side.
That is, the output signal B1 rises with a delay from the time when the polarity of the magnetic flux is switched from the S side to the N side, and conversely, the output signal B1 is earlier than when the polarity of the magnetic flux is switched from the N side to the S side.
Falls.

FIG. 11 shows the output signal B of each of the Hall ICs 34A, 34B and 34C accompanying the movement of the mover 30.
1, B2 and B3 are shown. The output signals B1, B2, and B3 are added to the pulse generator 64 shown in FIG. 1, and the rising and falling of this waveform are captured.
Pulses P1 to P7 are generated and applied to the speed calculator 58 and the position calculator 52.

The speed calculator 58 calculates the speed of the mover 30 based on the period of the pulses P1 to P7. Then, the speed corrector 59 corrects the calculated speed. This processing will be described in detail with reference to the flowchart in FIG. Here, the processing when the pulses P1 and P2 are sequentially applied to the speed calculation unit 58 will be described. First, the speed of the mover 30 is calculated (S101). Here, the interval of the magnetic sensor of 8 mm is set to the time between pulses (pulse P1).
To the pulse P2) to determine the speed. At the timing when the speed is calculated based on the pulse P2, the Hall IC 34 before the pulse P2 is input.
It is determined whether all of the output signals B1, B2, and B3 of A, 34B, and 34C are on (S103). Here, Hall IC
Since the output signal B2 of 34B is off, the step 10
3 is No, then the Hall IC before the pulse P2 is input
It is determined whether the output signals B1, B2, B3 of 34A, 34B, 34C are all off (S105). Here, Hall I
Since the output signal B1 of C34A is on, step 105 becomes No, the process proceeds to step 111, and the speed calculated in step 101 is output as it is to the output calculation unit 57 as the correction speed. Then, the same processing as described above is performed for the pulse P3.

Here, the processing when the pulse P4 is applied to the speed calculating section 58 will be described. As shown in FIG. 11, a pulse P capturing the rising of the Hall IC 34C
The interval between the magnetic sensor 3 and the pulse P4 capturing the fall of the Hall IC 34A is short because the pulse P3 is delayed and the pulse P4 is advanced, and the distance of the magnetic sensor set to 8 mm as described above is set to 7 mm. It will be detected as a degree. That is, the interval between the magnetic sensors of 8 mm is set to the time between pulses (P
The calculated speed obtained by dividing (3 from P4) (S101) becomes faster than the actual speed. Therefore, step 1
03, Hall ICs 34A and 34 before pulse P3 input
By determining whether all of the output signals B1, B2, and B3 of B and 34C are on, a pulse P4 that captures the falling and that follows the pulse P3 that captures the rising is detected. That is, the output signal B1 between the pulse P3 and the pulse P4,
Since B2 and B3 are all turned on (S103 is Ye
s) The process proceeds to step 107, where the corrected speed is obtained by multiplying the speed calculated in step 101 by the detected distance 7 mm / the magnetic sensor interval 8 mm. After that, the pulse P
The processing is advanced for P5 and P6 in the same manner as P2 described above.

Next, the processing when the pulse P7 is applied to the speed calculator 58 will be described. As shown in FIG. 11, a pulse P6 capturing the fall of the Hall IC 34C.
And the pulse P that captures the rise of the Hall IC 34A
The interval with 7 is longer because the pulse P6 advances and the pulse P7 delays, and the distance of the magnetic sensor set to 8 mm as described above is detected as about 9 mm. That is, the calculated speed obtained by dividing the interval 8 mm between the magnetic sensors by the inter-pulse time (P6 to P7) (S101) is lower than the actual speed. Therefore, after the determination in step 103, in step 105, the pulse P
By judging whether all the output signals B1, B2, B3 of the Hall ICs 34A, 34B, 34C before 7 inputs are off, a pulse P7 capturing a rising edge is detected following a pulse P6 capturing a falling edge. That is, the pulse P
6. Since the output signals B1, B2, and B3 are all turned off between the pulses P7 (Yes in S105), the process proceeds to Step 109, and the speed calculated in Step 101 is set to 9 mm for the distance detected and 8 mm for the distance between the magnetic detection sensors. The correction speed is obtained by multiplying. In this way, the speed calculation unit 58 and the speed correction unit 59 calculate the speed accurately and output the calculated speed to the output calculation unit 57 side.

On the other hand, as described above, the position calculator 52 outputs the output signals B1 and B1 of the Hall ICs 34A, 34B and 34C.
B2 and B3 and pulses P1 to P7 are input. The position calculator 52 detects the position of the mover 30 by counting up and down the number of pulse inputs based on the output signals B1, B2, and B3, and outputs the detected position to the main controller 55 and the target calculator 56. .

The main controller 55 outputs a target position for operating the door. The target speed calculation unit 56 calculates a target speed to be operated based on a difference between the target position output from the main control unit 55 and the current position from the position calculation unit 52, and the set speed from the speed setting unit 53. I do. Output operation unit 57
Calculates the output (thrust) of the mover 30 and the direction of the output from the difference between the target speed from the target speed calculator 56 and the actual speed calculated by the speed calculator 58 and the speed corrector 59. . The PWM converter 60 converts the output value calculated by the output calculator 57 into a PWM value (pulse width modulation value). The transistor setting device 61 determines the direction of the output (thrust) indicated by the output calculation unit 57 and the Hall IC 34A.
Output signals B1, B2, B3 (movable element 30
And the permanent magnet 48), the movable coils 32a, 32b, 32c to be energized and the energizing direction are determined, and the respective drive transistors TRa to TR of the energizing device 63 are determined.
Set ON / OFF of c '. And the energizing device 63
Drives the transistor to be turned on indicated by the transistor setting unit 61 in accordance with the PWM value indicated by the PWM conversion unit 60, and controls the current so that the output (thrust) set by the output calculation unit 57 is obtained. Mover coils 32a, 32
b, 32c.

FIG. 7 shows the results of an experiment in which a 100 kg door was driven at a constant speed (0.2 m / s) by a brushless DC linear motor controlled by the control circuit 50. As described above with reference to FIG. 12, when the thrust of the linear motor is increased to drive a relatively heavy door, "chattering" occurs. In the first embodiment, as described above, In order to accurately calculate the actual speed, the door could be smoothly driven. Although not shown here, the automatic door drive performs a series of operations of accelerating at the start of driving, sending at a constant speed when the target speed is reached, and decelerating and stopping after approaching the stop position. In the linear motor speed correcting device of the present embodiment, the actual speed can be accurately calculated at the time of acceleration and deceleration. Therefore, it is possible to smoothly accelerate at the time of acceleration and to smoothly decelerate at the time of deceleration.

Next, a speed correcting device for a linear motor according to a second embodiment of the present invention will be described with reference to FIGS. Since the linear motor according to the second embodiment is the same as the first embodiment described above with reference to FIGS. 2 and 3, illustration and description are omitted. FIG. 5 shows a control circuit 50 of the second embodiment. Here, in FIG. 5, the same reference numerals are used for members having the same configuration as the control circuit 50 of the first embodiment, and the description is omitted. In the second embodiment, the timing for performing the speed correction is determined by the Hall IC 34.
The determination is made not from the output signals of A, 34B, and 34C but from the signal from the position calculation unit 52.

The position calculating section 52 supplies the output signals B1,
B2, B3 and pulses P1 to P from the pulse generator 64
7 has been input. The position calculation unit 52 detects the position of the mover 30 by counting up and down the number of pulse inputs based on the output signals B1, B2, and B3, and outputs the detected position to the main control unit 55 and the target calculation unit 56. ,
Further, as shown in FIG. 11, the magnetic detection sensors 34a, 3a
The position of the permanent magnet 48 with respect to 4b, 34c is output to the speed correction unit 59 as position count values 1, 2, 3,.

On the other hand, the pulses P1 to P7 are input to the speed calculating section 58 as in the first embodiment, and the speed of the mover 30 is calculated based on this cycle. Then, the speed corrector 59 corrects the calculated speed. This processing will be described with reference to the flowchart in FIG. Here, a process in which the pulses P1 and P2 are sequentially applied to the speed calculation unit 58 will be described. First, the speed of the mover 30 is calculated (S201). Here, the speed is obtained by dividing the interval 8 mm between the magnetic sensors by the time between pulses (the time from pulse P1 to pulse P2). Then, the position count value before the input of the pulse P2 is 6n−3 (here, n
Is an integer of 1 or more) (S203). Here, since the position counter value is "1" as shown in FIG. 11, the result of step 203 is No. Next, it is determined whether the position counter value is 6n (S205).
05 is also No, the process proceeds to Step 211, and Step 2
The speed calculated in 01 is output as it is to the output calculation unit 57 as the correction speed. The same processing as described above is performed for the pulse P3.

Here, the processing when the pulse P4 is applied to the speed calculating section 58 will be described. As shown in FIG. 11, a pulse P3 capturing the rising of the output signal B3
And the interval between the pulse P4 that captured the falling edge of the output signal B1 and the pulse P3 are delayed and the pulse P4 is advanced, and the interval is short. The distance of the magnetic sensor set to 8 mm is detected as about 7 mm. Will be. That is, the calculated speed obtained by dividing the interval 8 mm between the magnetic sensors by the inter-pulse time (P3 to P4) (S201) becomes faster than the actual speed. Therefore, in step 203, the pulse P3
By judging whether the position count value before input is 6n-3, it is detected whether the pulse P4 captures the falling following the pulse P3 capturing the rising. That is, here, the position count value “3” before the input of the pulse P3 is input, and since 6n−3 = 3 (Yes in S203), the process proceeds to step 207, and the detected distance is 7 mm / Calculate the correction speed by multiplying the magnetic sensor interval by 8 mm. After that, the pulses P5, P
For 6, the process proceeds in the same manner as in P2 described above.

Next, the processing when the pulse P7 is applied to the speed calculator 58 will be described. As shown in FIG. 11, a pulse P6 capturing the falling of the output signal B3,
The interval between the pulse P7 that captures the rising edge of the output signal B1 and the pulse P6 is long because the pulse P6 is advanced and the pulse P7 is delayed, and the distance of the magnetic sensor set to 8 mm is set to 9 mm.
It will be detected as about mm. That is, the interval 8 mm between the magnetic sensors is divided by the time between pulses (from P6 to P7) (S2
01) is lower than the actual speed. Therefore, after the determination in step 203, in step 205, the position count value before the pulse P7 is input is 6n.
By judging this, a pulse P7 whose rising edge has been detected following the pulse P6 whose falling edge has been captured is detected. That is, in this case, since the position count value “6” before the input of the pulse P7 has been input, step 205 is Yes.
Then, the process proceeds to step 209, and a corrected speed is obtained by multiplying the speed calculated in step 201 by the detected distance 9 mm / the magnetic sensor interval 8 mm.

In this way, the speed calculating section 58 and the speed correcting section 59 accurately calculate the speed and output it to the output calculating section 57. On the other hand, the target speed calculation unit 56 includes a main control unit 55
The target speed to be operated is calculated based on the difference between the target position output from the controller and the current position from the position calculator 52 and the set speed from the speed setting unit 53. Output operation unit 5
7 calculates the output (thrust) of the mover 30 and the direction of the output from the difference between the target speed from the target speed calculation unit 56 and the actual speed calculated by the speed calculation unit 28 and the speed correction unit 59. . Based on this, the PWM conversion unit 60 and the transistor setting device 61 calculate the command value, and in accordance with this, the energizing device 63 controls the transistor to control the mover coil 32a,
The movable elements 30 are driven by exciting the elements 32b and 32c.

In the first and second embodiments described above, the door is driven by the linear motor. However, the present invention is not limited to the door. For example, the present invention can be suitably applied to an article conveying apparatus used for conveying assembled parts. Also, an example in which three sensors are used as the magnetic detection sensors has been described.
When the above-mentioned sensors are used, it can be suitably applied. Further, in the above-described embodiment, the configuration in which the coil is provided on the mover side and the permanent magnet is disposed on the stator side has been described as an example. The present invention can also be suitably used for speed control of a linear motor in which a permanent magnet is arranged on the slave side. Further, in the above-described embodiment, in the process shown in FIG.
Calculate the speed in advance in step 1 and then execute step 10 if necessary.
7 and the correction in step 109, each pulse P1
By calculating the respective speeds corresponding to ~ P7,
It is of course possible to calculate an accurate speed corrected from the beginning.

In the above-described embodiment, the threshold value θ1 of the Hall IC has been described with reference to FIG. 10 as a uniform value both when the output signal B1 rises and falls. However, actually, since the Hall element has a hysteresis characteristic, the rise and fall slightly differ. According to the present invention, a correct speed is calculated by performing correction in steps 107 and 109 referred to in FIG. 4 or steps 207 and 209 referred to in FIG. 6 including an error due to hysteresis.

[0043]

As described above, according to the linear motor speed correcting device of the present invention, the speed of the mover can be accurately obtained by performing the correction at the timing when the calculated speed is not accurate. For this reason, the speed of the linear motor can be properly controlled, and a heavy object can be smoothly conveyed. Further, the present invention can be embodied by adding the above-described functions to the control program of the control device for the linear motor, and therefore can be easily implemented without increasing the cost of parts.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a control circuit of a three-phase brushless DC linear motor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a mover of the three-phase brushless DC linear motor according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a three-phase brushless DC linear motor according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating speed calculation and speed correction processing according to the first embodiment.

FIG. 5 is a block diagram showing an electrical configuration of a control circuit of a three-phase brushless DC linear motor according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating speed calculation and speed correction processing according to the second embodiment.

FIG. 7 is a graph showing a result of a speed test of the three-phase brushless DC linear motor according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a configuration of a linear motor according to the related art.

FIG. 9 is a circuit diagram of a control circuit of a linear motor according to the related art.

FIG. 10 is a time chart showing an output of a Hall IC.

FIG. 11 is a time chart showing a waveform of the pulse generator.

FIG. 12 is a graph showing a result of a speed test of a linear motor according to the related art.

[Explanation of symbols]

 Reference Signs List 20 brushless DC linear motor 30 mover 32a mover coil 34a magnetic detection sensor 40 stator rail 48 permanent magnet 50 control circuit

Claims (1)

(57) [Claims] 1. A mover, a stator rail, a plurality of magnetic detection sensors for detecting magnetism of a magnet array provided on the mover or the stator rail, and a mover based on a signal from the magnetic detection sensor. a velocity correction system for a linear motor comprising a that control circuit to drive on the stator rail, a pulse generator for generating a pulse at the rising and falling edge of the signal by the plurality of magnetic detection sensor outputs
Means , a speed calculating means for calculating a speed of the mover based on the pulse signal, and the magnetic detection from the output state of the plurality of magnetic detection sensors.
Out Due generated in the detection sensitivity of the sensor, a signal in which a plurality of magnetic sensor outputs rise and fall
Estimating the deviation of timing for magnet array, the speed correction device of a linear motor and having a a compensation unit that the speed calculating means is correct complement the rate at which calculated.