JPS5820049B2 - Actuyuetano Ichigi Mesei Giyohouhou - Google Patents

Description

[Detailed Description of the Invention] The present invention is capable of positioning an actuator such as an industrial robot at high speed at a close distance close to a target value, and also performs continuous servo control from a location quite far away from the target value. The present invention relates to a positioning control method for an actuator that can perform high-gain positioning, particularly by using a general high-sensitivity non-contact type sensor and a simplified amplifier circuit.

When positioning and controlling the operating end of an actuator in a handling machine, etc., it is recommended to use a high-sensitivity sensor as a control input element that can obtain a high output gain at a close distance close to the target value. From this point of view, conventionally, as shown in Fig. 1, a reflective full-disc sensor 1' such as a back pressure detection nozzle mechanism is used as a position detection element, and the straight line The pneumatic signal obtained by the high gain characteristic is converted into an electric signal by the pneumatic converter 2', and a control output is generated by the control device 3' having an amplifier circuit, and the drive device 4' is actuated to drive the actuator. A servo control system capable of controlling the displacement of 5 is often used.

However, although the reflective full disk sensor 1 has the advantage of being able to extract a highly sensitive pneumatic signal proportional to the error between the actual value and the target value when the sensor is close to the target point, However, since a pneumatic signal proportional to the error cannot be obtained, it is extremely difficult to perform feedback control smoothly from a remote location using the sensor 1, and furthermore, for actuator positioning, If speed control is to be performed during movement, a threshold value (THRESHOLD) for the required number of stages must be set in the control system, resulting in a problem that the circuit becomes complicated.

On the other hand, when a general-purpose non-contact sensor such as a light-to-electricity conversion type, magnetic quantity, or air quantity-to-electricity conversion type is used as a position detection element, the output characteristics change near zero, which is close to the target value. Since it has a high detection function and a detection function from a fairly distant point, it is suitable for feedback control from a remote point and can solve the drawbacks of the above example. Many of them have non-linear characteristics where the output speed is reversed near the target point. Therefore, when combined with a general output amplification mechanism, it is difficult to perform continuous speed control near the target point, so a special amplification mechanism is required. Since it must be coupled to a circuit, it has tended to be avoided in cases where the problem of complicating the device arises and requires highly sensitive positioning control.

The present invention focuses on the fact that various conventional sensors have advantages and disadvantages in their characteristics and cannot meet the demands of users, and rather effectively utilizes the unique functions of sensors with nonlinear characteristics. One point threshold.

This method is characterized by providing a new positioning control method that enables actuator control from a remote location and also enables high-speed positioning when the target value is closest to the target value. The method of the present invention will be described in detail below with reference to the accompanying drawings. As mentioned above, the method of the present invention uses a position detection sensor 1 having a non-linear output distance characteristic such as a magnetic non-contact switch as a control input element for an actuator 5.
It is integrally attached to the working end.

As shown in the output-distance characteristic of the sensor 1 in FIG. , has a nonlinear characteristic in which the output changes in the order of the third output region S3 of increasing output, and when the distance X from the target point P is Xl, the output increases as the distance decreases, and when X2, the output increases. In the case of X3, the output increases.

In the region S3 close to the target point P, a high output gain detection characteristic is obtained.

The control device 3 electrically connects the sensor 1 having the following characteristics to each output region S1+S2 . For S3, the circuit is designed to have one output threshold value that can be crossed at points a + b + c, and for example, at the first threshold value, that is, point a, the intermediate value is set based on the differential value in the direction of output increase. After emitting an output at the output level, this output level is held until the point of firing, and then, at the second threshold, that is, at the point of firing, the output is converted to a lower output level based on the differential value in the direction of decreasing the output. After that, this output level is held until reaching point C, and at the third threshold value, that is, point C, the output is converted to a high output level by the differential value in the output increasing direction, and then the amplification degree of the third region S3 is changed. It is preset to continuously output a high output proportional to .

Then, these three levels of output are given to the drive device 4.

The actuator 5 is caused to perform a displacement corresponding to the output, and the positioning of the working end of the actuator 5 is controlled.

As a specific structural example of the control device 3 that operates as described above, there are two well-known and commonly used circuits, namely, a comparator 6 for threshold setting (design of a circuit made by CQ Publishing Company in 1927) by Okamura. ), transition detection/frequency doubling circuit 7 (see "Transistor Technology, February 1974 issue," published by Thinky Co., Ltd., pages 155-156), and stepping relays, which are well-known and commonly used relays in control equipment. 8 (Jikkyo Publishing Co., Ltd. February 28, 1974)
``Fundamentals and Applications of Automatic Control'', co-authored by Hiroyuki Takai and Kensuke Haseyo, published in the 4th edition. 67 to 69) simply connected in series, and is a simple circuit as schematically shown in FIG.

In this device, a comparator 6 compares the output signal e1 of the sensor 1 with a reference voltage corresponding to a threshold value, and outputs an output e2 having rising and falling edges alternately. is received by the transition detection/frequency doubling circuit 7, which generates a pulse output e3 at the time of rising and falling, respectively.Furthermore, this pulse output e3 causes the stepping relay 8 to move the contact one frame at a time each time the electromagnetic coil is excited. Accordingly, it operates to issue control commands in response to pulse outputs based on a preset order.

An example of positioning control according to the method of the present invention using the servo control device configured in this way will be described below.At a distance beyond X0 away from the target point P, the actuator 5 is driven in the normal speed range to reach the target point P. On the other hand, move it closer at a constant speed.

When the separation distance reaches X, as is clear from the above explanation, the control device 3 reaches the first threshold, so it changes the output level and operates the actuator at a medium speed that is slightly faster than the normal speed range. 5, the drive device 4
Issues a command to increase pressure.

In this way, the actuator 5 moves at a medium speed until the distance X2 reaches the second threshold, and when the threshold is reached, the control device 3 changes the output level, so the actuator 5 is moved at a low speed range. As in, drive device 4
Issues a pressure reduction command to.

Therefore, the actuator 5 moves at a low speed until the distance X reaches the threshold for the third time, and during this movement, the inertia possessed by the actuator 5 is eliminated, and then when the threshold is reached, the control device 3, since the output changes again, a pressure increase command is issued to the drive device 4 to move the actuator 5 in a high speed range, and the actuator 5 is moved close to the target point P at high speed, thus controlling the speed. This allows precise positioning to be performed step by step.

As described above, in the present invention, the actuator 5 moves the position detection sensor 1 having the non-linear output distance characteristic in the order of the first to third output ranges in the process of approaching the target point p.
A control output is sent to the actuator 5 via a control device 3 which is used as a control input element and has one threshold that intersects each of the output regions, and which causes an output to be generated at the threshold for each region. Since it is characterized by a positioning control method in which the control device is applied, it may be a simplified mechanism because the control device can design a circuit with one threshold value, and it may be possible to have three stages of output with one threshold value. Since it is possible to obtain a signal, this type of sensor has traditionally been avoided because it has unique detection characteristics when determining position.
This has the advantage that positioning accompanied by speed control can be performed more accurately, and the utility of the general-purpose position detection sensor 1 can be further increased.

Furthermore, the present invention provides a sensor 1 with high output gain near zero.
It is most suitable for precision positioning because it can perform high-speed positioning at a close distance to the target value.
This is an extremely useful positioning control method when applied to industrial robots, etc.

[Brief explanation of the drawing]

Figure 1 is a system diagram of a control system related to a conventional actuator.
FIG. 2 is a control system diagram of an actuator implementing the method of the present invention, and FIG. 3 is an output characteristic diagram of the position detection sensor in FIG. 2. Moreover, FIG. 4 is a specific circuit diagram of the control device in FIG. 2.0 1...Position detection sensor, 3...Control device, 5...Actuator.

Claims (1)

[Claims] 1 Light quantity-electricity quantity conversion having a nonlinear output distance characteristic in the order of a first output region where the output increases, a second output region where the output decreases, and a third output region where the output increases in the process of approaching the target point. A position detection sensor 1 such as a shape sensor is used as a control input element for an actuator 5, and has one threshold that intersects the first to third output regions, and outputs at the threshold for each region. A method for controlling the positioning of an actuator, characterized in that a control output is applied to the actuator 5 via a control device 3 that causes the actuator 5 to issue a control output, respectively.