JP2003099130A - Positioning device for traveling object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning device capable of improving positioning precision in a simple structure, and preventing any failure to be generated in a positioning operation due to play of a driving system. SOLUTION: The positioning of a traveling object 1 to a detection (target) position is carried out by operation processes ranging from (a) to (c) in figure 1. When the detection signal of a detecting means 2 is changed at the target position when the traveling object 1 moves forward for the first time, the traveling object 1 is allowed to overrun in a fixed distance without immediately being controlled to stop. Afterwards, the traveling object is controlled to move at low speed toward the target position backward, and immediately when the detection signal is changed, a driving source is controlled to stop so that the traveling object can be positioned. Thus, it is possible to reduce inertia, and to fix the movement of the traveling object just before the traveling object is positioned, and to absorb the play and backlash of the driving system against the backward movement. When the traveling object is restarted forward after stopped, the traveling object is allowed to repeatedly overrun in the fixed distance at the opposite side so that the traveling object can be positioned in the same way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving object positioning apparatus, and a movement control for controlling the movement / stop of a moving object at a target position according to a detection signal of a sensor for detecting the presence of the moving object at a positioning target position. The present invention relates to a positioning device that performs positioning by means.

[0002]

2. Description of the Related Art Positioning devices having a movement / stop control means for stopping the moving object at an appropriate position by detecting the position of the moving object and performing stop control by a detection signal have been conventionally used in many fields. Has been used since. The positioning method is such that stop control of a moving object is detected when it is detected that a moving moving object is at a target (detection) position by a detection signal from a position detection unit such as a sensor that detects the position of the moving object. The method is generally used. However, this method does not consider the motion state of the moving object immediately before stopping or the state of transmission of power to the moving object. Therefore, if these states are different, inertia of the moving object, play of the drive system, etc. Varies from stop to stop, and variations occur. This causes problems such as poor positioning accuracy and backlash of drive system gears. For example, if the backlash is large, there is a problem that there is a time lag before the moving object starts moving even if the power source is started,
In the case where a stepping motor or the like is used as a power source, when backlash is eliminated during acceleration, a problem arises in that a sudden increase in load causes step-out. In order to overcome such a problem, a moving object requires a higher speed or a stronger power source, which increases the cost of a device, system or product using the moving object.

Therefore, another position detection sensor is provided upstream (on the movement path) of the position detection sensor for performing stop control, and the speed of the moving object is detected when the upstream sensor detects the moving object. It is known that deceleration is started and stop control is performed when a downstream stop control sensor detects a moving object (see Japanese Patent Laid-Open No. 10-301215.
In this conventional example, a moving object is a document, and the position detection sensors are upstream separation sensors 30 that detect the rear end of the document, respectively.
The paper feed sensor 35 on the downstream side) is used to overcome the above problem.

[0004]

The problems of the prior art described above can be solved for the time being. However, according to this conventional device, since two sensors are required on the upstream side and the downstream side, it cannot be denied that the cost will increase accordingly. Therefore, in order to make the configuration simpler than the conventional one, the present invention requires only one moving object position detecting means, and further improves the positioning accuracy when the moving object is stopped as compared with the conventional one, and It is an object of the present invention to provide a positioning device capable of improving a problem that occurs in a positioning operation due to a play of a drive system which has been conventionally varied when stopped.

[0005]

According to a first aspect of the invention, the predetermined position is targeted by a moving object position detecting means for detecting the presence or absence of a moving object at the predetermined position and a detection signal of the moving object position detecting means. A moving object positioning device having a moving object movement control means for controlling movement / stop of a moving object as a stop position, wherein the movement control means reverses the moving object from a state in which a target stop position is overrun. The moving object positioning device is characterized in that stop control is performed when the detection signal of the moving object position detecting means changes in a direction.

According to a second aspect of the present invention, in the moving object positioning apparatus according to the first aspect, the movement control means comprises:
The feature is that the operation of overrunning the target stop position is repeated.

According to a third aspect of the present invention, in the moving object positioning apparatus according to the first or second aspect, the movement control means exceeds the target stop position in a direction coinciding with a direction of re-moving after the stop control is completed. The stop control from the run state is terminated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the basic concept of the present invention will be described first.
FIG. 1 is a diagram for explaining the basic principle of the present invention.
In FIG. 1, the movement of the moving object 1 is controlled by the operation of a movement control device (not shown), and the moving object 1 changes its position with respect to the position detecting means 2 in the order of (a) → (b) → (c). Indicates. FIG. 1A is a diagram showing a state in which the moving object 1 is moving in the forward direction toward a target position (a detection position shown in the drawing). In the state shown in the figure, the position detection means 2 has not yet output a detection signal to be issued when the moving object 1 is at the target position. When the moving object 1 continues to move and approaches the target position, a detection signal that changes at the target position is output, and the movement is controlled by the detection signal. Here, stop control is performed by overrunning a predetermined (constant) distance by this detection signal. When overrunning, the moving object 1 is in the state of FIG. In the example of the conventional single sensor, the stop signal is immediately controlled by this detection signal. Therefore, the above-mentioned problems shown in the related art are caused. After that, the moving object 1 is controlled so as to move from the overrun position to the target position in the opposite direction shown by the arrow in FIG. When the moving object 1 continues to move in the opposite direction and approaches the target position, the position detection means 2 outputs a detection signal that changes at the target position, and the movement is controlled by the detection signal. here,
Immediately after the detection signal is output, the drive source is stopped to stop the moving object 1, and the moving object 1 is positioned at the target position shown in FIG.

According to such a stop control method for a moving object, positioning is performed by a control operation from an overrun position of a fixed distance from a target position in any positioning operation, so that the moving object immediately before positioning is moved. The movement can be controlled to be constant. In other words, at the overrun stop position, the state of the drive system at the time of stop control differs depending on each operation, so the play and gear backlash that occur at that time vary, but due to the control operation from the overrun position The variation can be absorbed. In this case, the play of the drive system and the backlash of the gear can be absorbed by the movement in the opposite direction to be constant. Further, by slowing the movement in the opposite direction related to the positioning, it is possible to effectively reduce the play of the drive system and the gear backlash during the positioning. That is, since the speed immediately before the stop is low, it is possible to eliminate or reduce the amount that the moving object moves due to the play of the drive system or inertia due to the backlash after the drive source stops. is there. Furthermore, since the speed immediately before the stop is low, the moving distance can be shortened from the detection of the detection signal changing at the target position to the stop of the drive source. This means that when there is a variation in the time from the detection of the detection signal that changes at the target position to the stop of the drive source, the positioning accuracy of the stop position is increased.
As described above, the invention whose principle is described with reference to FIG. 1 is particularly useful for positioning a moving object in which the moving object reciprocates or repeats.

The basic principle of the invention described below is, in addition to the above-described invention whose principle has been described with reference to FIG. 1, in consideration of the directionality of movement, the improvement of the positioning accuracy and the deterioration of the positioning accuracy due to the play of the drive system. Involved in an invention for improvement. Figure 2
FIG. 4 is a diagram for explaining the basic principle of the present invention. FIG. 2 shows a moving object 1 caused by the operation of a movement control device (not shown).
Is controlled, and (a) → (b) → (d) →
The manner in which the moving object 1 changes its position with respect to the position detecting means 2 in the order of (e) is shown. FIG. 2A shows a state in which the moving object 1 is moving in the forward direction toward the target position (the detection position shown in the figure), and FIG. 2B shows the reverse position shown by the arrow from the overrun position. It is a figure which shows the state which moves toward a target position in the direction. The movement control operation of the moving object 1 shown in FIGS. 2 (a) and 2 (b) is the same as the above invention (FIGS. 1 (a) and 1 (b)).
See). Therefore, the above description refers to the above description. The moving object 1 is shown in FIG.
It is controlled so as to move from the overrun position in (b) to the target position in the opposite direction shown by the arrow in the figure, and when it approaches the target position, a detection signal that changes at the target position is output. The stop control is not performed immediately by the detection signal as in the above invention, but the stop control is performed by overrunning a predetermined (constant) distance by the detection signal. When the moving object 1 is overrun, the moving object 1 moves as shown in FIG.
The state is (d). This stop position is in a state where it is overrun in the reverse direction, in a relationship exactly opposite to that in the case of overrunning in the forward direction. After that, the moving object 1 is controlled so as to move from the overrun position to the target position in the forward direction shown by the arrow in FIG. When the moving object 1 continues to move in the forward direction and approaches the target position, the position detection means 2 outputs a detection signal that changes at the target position, and the movement is controlled by the detection signal. Here, the driving source stop control is immediately performed by the output of the detection signal, and the moving object 1
Is stopped and positioning to the target position shown in FIG. According to such a stop control method for a moving object, after repeating the control operation to the overrun position of a certain distance from the target position, the positioning is performed by the low speed control operation from the overrun position of the certain distance. A function for achieving the same effect as the above-described invention described in 1 above is repeated, the positioning accuracy is further enhanced, the play of the drive system and the backlash of the gear are absorbed, and the operation state of the drive system is made constant. Can be further increased.
As described above, the invention whose principle has been described with reference to FIG. 2 is particularly useful for positioning a moving object in which the moving object is temporarily stopped while being moved in a certain direction (forward direction) and then moved again. .

An embodiment of a moving object positioning apparatus constructed based on the above-mentioned basic concept of the invention will be exemplified and described. FIG. 3 shows a schematic configuration of an embodiment of a positioning device according to the present invention. The positioning device shown in the figure includes a stepping motor 7 and a motor driver 6 that constitute a drive device for the moving object 1, a movement control unit 5 that controls the drive device to move / stop the moving object 1, and performs positioning control, and a positioning control. For this purpose, a position detecting means 2 for outputting a position detection signal of the moving object 1 to the movement control unit is provided. Various forms are conceivable as the position detecting means 2 of the moving object used when implementing the present invention. For example, a device that includes a micro switch and uses ON / OFF of the micro switch. Alternatively, the position is similarly detected by a reflection type sensor or a photo interrupter. Alternatively, various types of position detecting means such as a laser, a magnet switch, and an ultrasonic wave are conceivable. Here, an example using a photo interrupter will be described. As shown in FIG. 3, the photo interrupter 2 has a fixed portion provided with a detection means including a light beam emitting portion and a light receiving portion so as to be shielded by a light shielding plate 3 provided on a part of the moving object 1. The detection signal is issued when the light beam is changed from the light receiving state to the light shielding state or from the light shielding state to the light receiving state.

The basic operation during positioning in the positioning apparatus of FIG. 3 will be described. The movement control section 5 controls the motor driver 6 according to the movement speed set in the control section to drive the stepping motor 7. The moving object 1 is moved by moving the moving object 1 by driving the stepping motor 7.
When the light shielding plate 3 of 3 shields the light beam of the photo interrupter 2 set at the positioning target position, a detection signal is emitted. The movement control unit 5 that receives the detection signal from the photo interrupter 2 controls the motor driver 6 to stop the moving object 1 at this position, stops the moving object by the control operation, and performs positioning to the target position. . This positioning control is executed by the operation according to the above-described inventive principle.

FIG. 4 is a schematic diagram for explaining the operation of the embodiment of the positioning apparatus using the photo interrupter shown in FIG. 3 as the position detecting means of the moving object. Figure 4
The operation will be described in detail with reference to FIG. 4A. In FIG. 4A, the moving object 1 carries the light blocking plate of the photo interrupter 2 toward the photo interrupter 2 (direction of the target position) which is the position detecting means. It is a figure which shows the state which is moving (corresponding to FIG.1 (a) and FIG.2 (a)). In this state, the optical path of the photo interrupter 2 is not shielded by the light shield plate 3 yet, so that the position of the moving object 1 is not detected.
After that, the moving object 1 continues to move and emits a detection signal when the light blocking plate 3 is in a state of blocking the light beam of the photo interrupter 2. The detection signal is used as a control timing signal to perform a predetermined overrun operation and stop at the position of FIG. 4B (corresponding to FIG. 1B and FIG. 2B). Next, when the movement starts in the opposite direction shown by the arrow in FIG. 4 (b) from the stop position and reaches the position shown in FIG. 4 (c) (corresponding to FIG. 1 (c)), the light-shielding state is changed to the light-receiving state. The photo interrupter 2 generates a detection signal at that time. Using this detection signal as a control timing signal, the stop control of the stepping motor 7 is immediately started. The operation of stopping at the position shown in FIG. 4 (c) is an operation according to the inventive principle of FIG. 1 (note that the above description is referred to for the operation related to FIG. 1).

In operation according to the inventive principle of FIG.
When the position shown in (c) is reached, the photo interrupter 2
The detection signal generated by the control timing signal,
A predetermined overrun operation is performed and stopped at the position shown in FIG. 4D (corresponding to FIG. 2D). Next, the movement from the stop position is started in the forward direction indicated by the arrow in FIG.
When the position shown in (e) (corresponding to FIG. 2E) is reached, the light receiving state is changed to the light blocking state, and at that time, the photo interrupter 2 generates a detection signal. Using this detection signal as a control timing signal, the stop control of the stepping motor 7 is immediately started. The operation of stopping at the position shown in FIG. 4E is in accordance with the inventive principle of FIG.
For the operation related to, refer to the above description). Further, in this example, in the operation shown in FIG.
As a method of detecting the detection signal for positioning by the photo interrupter 2, the same end portion (the right end in the illustrated example) of the light shielding plate 3 is detected regardless of whether the moving direction is reverse or forward. In the opposite case, a detection signal is output when the light receiving state is obtained (FIG. 4C), and when it is in the light shielding state (FIG. 4E), the detection signal is output. Different in points.

As an embodiment using the photo interrupter 2 as the position detecting means, in view of the relative relationship between the moving object and the position detecting means, a sensor such as a photo interrupter is mounted on the moving object and the detection plate is placed at a predetermined position. Modifications of the present invention, such as fixing, can be easily made by those skilled in the art.
Further, it goes without saying that the moving object to be positioned by the positioning device of the present invention is not limited to the one that moves linearly, and can be applied to, for example, one that moves circularly or rotationally.

The embodiments described above can be applied to an image forming apparatus (copying machine, printer, facsimile machine, image scanner, etc.). For example, it can be applied to various parts such as home position positioning of a scanner of an image forming apparatus, home position positioning of a revolver developing of a color image forming apparatus, or home position positioning relating to movement of a lens for changing the image forming apparatus. As a result, the accuracy of the stop position of the moving object can be improved, and problems such as step-out of the stepping motor of the drive source can be solved, so that image performance can be improved by accurate positioning.

[0017]

(1) Effects corresponding to the inventions of claims 1 and 2 It is detected by one position detecting means that the moving object has reached the target position, and a predetermined distance is overrun in the first operation, and the position is moved. Since the positioning is performed by stop control by the detection signal of the position detection means by the low-speed return operation, the structure is simpler and the cost is lower than that of the conventional position detection device.
It is possible to solve the problems of inertia at the time of stop and the problems caused by the play of the drive system, and improve the positioning accuracy of the moving object at the time of stop. Further, by repeating the low speed control operation from the overrun position of a constant distance, the above-described effect can be further enhanced, and the optimum state for the operation after the stop can be set. (2) Effect corresponding to the invention of claim 3 In addition to the effect of (1) above, since the device condition can be set in an optimum state according to the moving direction at the time of restarting after positioning, reciprocating movement is possible. In each operation of intermittent movement in one direction, the maximum effect can be achieved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of a positioning device according to the present invention.

FIG. 2 is a diagram for explaining the principle of a positioning device according to another invention of the present application.

FIG. 3 shows a schematic configuration of an embodiment of a positioning device according to the present invention.

FIG. 4 is a schematic diagram for explaining an operation of an embodiment of a positioning device that uses a photo interrupter as a position detecting unit for a moving object.

[Explanation of symbols]

1 ... Moving object, 2 ... Position detecting means (photo interrupter), 3 ... Light shield plate,
4 ... Optical axis, 5 ... Movement control unit, 6
… Motor driver, 7… Stepping motor.

Claims (3)

[Claims] 1. A moving object position detecting means for detecting the presence or absence of a moving object at a predetermined position, and a detection signal from the moving object position detecting means for moving or stopping the moving object with the predetermined position as a target stop position. A moving object positioning device having moving control means for controlling a moving object, wherein the movement controlling means moves the moving object in a reverse direction from a state where the target stop position is overrun, and A moving object positioning device characterized by performing stop control when a detection signal changes. 2. The moving object positioning apparatus according to claim 1, wherein the movement control means repeatedly performs an operation of overrunning a target stop position. 3. The moving object positioning apparatus according to claim 1 or 2, wherein the movement control means is configured to move the target stop position from an overrun state in a direction coinciding with a direction of re-moving after the stop control is completed. A moving object positioning device characterized by terminating the stop control.