JP2818726B2 - Non-contact traveling body stop control mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport device in which a linear motor is used for acceleration and deceleration, and a traveling body floats and travels by air pressure. The present invention relates to a stop control mechanism for a non-contact traveling body in which the direction and the size of a side linear motor are switched to stop accurately and quickly at a stop position.

[0002]

2. Description of the Related Art In recent years, factory automation in semiconductor manufacturing plants for LSIs and the like, pharmaceutical manufacturing plants, and the like has made remarkable progress. However, factory automation, if done incorrectly, can cause dusting of machinery and equipment, which can adversely affect products. Therefore, there is a demand for a dust-free transport device. Japanese Patent Application Laid-Open No. Sho 59-124623 discloses a dust-free transfer device that meets this requirement.
The one described in Japanese Patent Application Publication No. HEI 9-203 is known. This transport device uses a linear motor having no rotating part as a drive device, and further eliminates all mechanical friction by floating the running body in air, which meets the above-mentioned purpose. After the traveling body passes the stop point, the non-contact traveling body is stopped at a fixed position by switching the direction and the size of the linear motor by a timer.

[0003]

In the conventional traveling body stop control mechanism, the direction and the size of the linear motor are switched by a timer after passing the stop point, so that the traveling body is strong even though it is approaching the origin. In order to work back,
There was a drawback that it took time to repeatedly stop overrun.

According to the present invention, a simple comb-shaped striker is attached to a traveling body to detect the speed and to adjust the direction and frequency of a linear motor on the ground so that the traveling body pulls back with a strong force when the traveling body moves away from a stop point. An object of the present invention is to provide a stop control mechanism that switches a direction and a frequency of a linear motor so that the linear motor returns to a stop point with a weak force at a point of zero speed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and comprises a linear device disposed on a transport path while straddling the transport path and floating with air ejected from the transport path. In a non-contact traveling body driven by a motor, two linear motors are provided at a traveling body stop position of the transport path so as to be opposed to each other with the stop position interposed therebetween, and the traveling body has a speed. A comb-shaped striker for measuring the stop position and an origin striker for detecting the stop position,
Equipped with a speed detection sensor and an origin detection sensor on the ground side of the traveling path, the direction of the linear motor on the ground side is set so that these sensors and the linear motor pull back with a strong force when the traveling body moves away from the stop point. Connect a control device that switches the direction and frequency to the linear motor so that a frequency is given and the speed returns to the stop point with a weak force at the point of speed 0, and the speed is measured by detecting ON / OFF of the striker with each sensor And
The gist is to control the magnitude and direction of the thrust of the linear motor based on the speed to stop the traveling body at a fixed position.

[0006]

[Function] As a result of measuring the relationship between the displacement of the traveling body and the command value to the linear motor, in the method of switching the frequency of the linear motor on the ground side with a timer, the time when the speed becomes zero due to the weight of the traveling body, the approach speed, etc. Due to the variation, it takes a long time for the running body to swing and stop due to the repetition of a situation in which the running body is returned with a strong force while approaching the stop point. Therefore, a point at which the speed of the traveling body becomes 0 is detected, and the linear motor is switched to a weak force to return to the stop point. When the traveling body enters the stop position and the striker kicks the origin sensor, the two linear motors are excited at a high frequency (50 Hz) toward the center of the stop position (opposed excitation). The traveling body receives a strong force in the direction of the stop point and decelerates, and eventually the velocity of the traveling body becomes zero.
Is detected with a comb-like striker, the linear motor is switched to a low frequency (10 to 20 Hz) and returned to the stop point with a weak force to reduce overrun. Stop exactly.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-contact traveling body stop control mechanism according to the present invention will be described below with reference to the illustrated embodiment. In the drawing, reference numeral 1 denotes a transport path, on which a compressed clean air supplied from a separately provided air supply unit is provided on the upper surface of the transport path 1 over substantially the entire length thereof, and also on the side surface as necessary. Discharged through a nozzle, the traveling body 2 is levitated and supported, and a linear motor is arranged along the transport path 1 so that the traveling body 2 travels at a predetermined speed. In addition, two linear motors 3 and 4 are disposed adjacent to each other at a predetermined stop position of the traveling body 2 on the transport path 1 so as to be oppositely excited at front and rear positions with respect to the stop position.
The running and braking of the running body are performed by controlling the linear motors by the control device.

The traveling body 2 is provided with a comb-shaped striker 6 for measuring the speed on one side and an origin striker 5 for detecting a stop position on the other side. The origin striker is disposed at a predetermined position, but the comb-shaped striker 6 for measuring the speed is disposed linearly over the longitudinal direction of the traveling body.

The transport path 1 is set on the transport path 1 so as to coincide with the traveling locus of the traveling body 2 traveling along the transport path 1.
Is provided with a pair of speed detection sensors 81 and 82 on one side and an origin detection sensor 7 for detecting a stop position on the other side, and each sensor is operated by each striker as the traveling body travels. Eggplant And a pair of two speed detection sensors 8
Numerals 1 and 82 are arranged with a 1/4 phase shift, so that not only the speed of the traveling body but also the traveling direction is detected.

A control device 9 having a control circuit for controlling the linear motors 3 and 4 based on signals from operating the sensors 7, 81 and 82 with each striker is used to control the sensors 7, 81 and 82 and the linear motors 3 and 4. Make an electrical connection.

Therefore, in the apparatus formed as described above, the traveling body traveling along the transport path reaches a predetermined stop position, the origin sensor detects the origin striker, and the traveling body further travels. As soon as the sensor detects the origin striker, the control circuit switches the linear motor 4 to the opposite excitation at a high frequency, so that the traveling body is subjected to a strong force in the direction toward the stop position to be decelerated and braked. Then, when the traveling body passes the stop position and the speed is 0, that is, the stop is detected by the comb-shaped striker, the linear motor 4 is switched to a low frequency and the traveling body is moved backward by a weak force. Then, when the speed of the traveling body that moves backward is again 0 after the stop position, that is, the stop is detected by the comb-shaped striker, the linear motor 3 is switched to a low frequency to advance the traveling body with a weak force. By sequentially repeating this operation, the traveling body is reliably stopped at a fixed position with a small number of swings.

[0012]

According to the present invention, the stop control mechanism for a non-contact traveling body includes:
Measure the timing and traveling direction of the traveling speed 0 of the traveling body,
Since the stop point is returned to the stop point with a small force so as to minimize the overrun, there is an advantage that the number of swings can be reduced and the time until the stop is shortened, as compared with the method controlled by the timer.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of a non-contact traveling body stop control mechanism of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is an explanatory diagram of stopping a traveling body at a fixed position.

FIG. 4 is an explanatory diagram of a fixed position stop graph.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveyance path 2 Running body 3, 4 Linear motor 5 Origin striker 6 Comb striker 7 Outer point sensor 81, 82 Speed detection sensor 9 Control device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02P 7/00 B60L 13/02 G05D 3/12

Claims (1)

(57) [Claims] 1. A non-contact traveling body that straddles a transport path and is run by a linear motor disposed on the transport path while being levitated by air ejected from the transport path. At the stop position, two linear motors are disposed so as to be opposed to each other with the stop position interposed therebetween, and a comb-shaped striker for measuring the speed and an origin striker for detecting the stop position are provided on the traveling body. A speed detection sensor and an origin detection sensor are provided on the ground side of the traveling path, and the direction of the linear motor on the ground side is set so that the sensor and the linear motor are pulled back by a strong force when the traveling body moves away from the stop point. The linear motor is connected to a controller that switches the direction and frequency to return to the stop point with a weak force at the point of zero speed.
The non-contact traveling body is characterized in that the velocity is measured by detecting N and OFF, and the magnitude and direction of the thrust of the linear motor are controlled based on the velocity to stop the traveling body at a fixed position. Stop control mechanism.