JPH0681810A - Fluid actuator synchronization controller - Google Patents

Abstract

PURPOSE:To precisely synchronize all fluid actuators even if there is any fluid actuator subjected to an excessive load among them. CONSTITUTION:The latest fluid actuator 5 subjected to an excessive load is discriminated by a controller 52. The control of this latest fluid actuator 15 aiming at its position is converted into its control aiming at its speed and the other actuators 16, 17, 18 other than the latest one are feedback-controlled by taking a third position target signal formed on the basis of the current position and the current speed of the latest fluid actuator 15 as a target of the control. Thereby, even if a fluid actuator delayed by its excessive load condition, appears, synchronization can be maintained by making the other actuators to follow up the delayed actuator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuning controller for a fluid actuator used in an injection molding machine, a hydraulic press or the like.

[0002]

2. Description of the Related Art Conventionally, as a tuning controller for a fluid actuator, there is one as shown in FIG. This fluid actuator tuning control device drives four hydraulic cylinders in synchronism with each other, and a speed setting value and a position setting value indicating which position and speed are driven by the setting means 1 are set. The position target signal generation means 2 generates a position target signal for each time based on the inputted speed set value and the position set value. Then, the position control means 3 calculates the deviation between this position target signal and the signal representing the current position of each hydraulic cylinder 5 input from each position sensor 6, and the signal representing this deviation is sent to each control valve 4. Output and drive each hydraulic cylinder 5 (only the A-axis hydraulic cylinder among the four A-axis, B-axis, C-axis, and D-axis hydraulic cylinders is shown) by the position target signal to perform tuning. I try to control it. That is, as shown in FIG.
Feedback control is performed so that the four hydraulic cylinders of the B-axis, C-axis, and D-axis follow the position represented by the position target signal that is a common control target, that is, the position of the hydraulic cylinder follows the control target.

[0003]

However, in the above-mentioned conventional tuning controller for fluid actuators, when the load of one hydraulic cylinder becomes equal to or more than its output, feedback control of that hydraulic cylinder is performed. It becomes impossible to do it, it becomes slower than the set speed, and it becomes impossible to follow the position target represented by the position target signal,
On the other hand, since the other hydraulic cylinders operate following the position target indicated by the position target signal, the synchronized state cannot be maintained. That is, in the tuning controller for the fluid actuator,
Whether or not the hydraulic cylinder is overloaded,
Since the position target signal was updated, the hydraulic cylinders that were overloaded remained delayed, and the hydraulic cylinders that were not overloaded proceeded according to the position target signals, and could not be synchronized.

Therefore, an object of the present invention is to detect whether or not the fluid actuator is in an overloaded state, and when it is determined that the fluid actuator is in an overloaded state, determine the position or speed of the fluid actuator that is the most delayed. Based on the above, it is an object of the present invention to provide a tuning controller for a fluid actuator that can maintain tuning even in the presence of an overloaded fluid actuator by generating a position target signal for another fluid actuator.

[0005]

To achieve the above object, a tuning control device for a fluid actuator according to a first aspect of the present invention controls a plurality of fluid actuators to be actuated in synchronization and the speed of each fluid actuator. A control valve, a position sensor for detecting the position of each of the fluid actuators, an overload detection means for detecting that each of the fluid actuators is in an overload state, and an output of the overload detection means, First position target signal generation means for generating a first position target signal for each of the fluid actuators based on an input set value when it is determined that none of the fluid actuators is overloaded; If it is determined that one of the fluid actuators is overloaded based on the output of the overload detection means, the latest One of the fluid actuators is overloaded based on the output of the velocity target signal generating means for generating a velocity target signal for the fluid actuator based on the input set value and the overload detecting means. When it is determined that the third position target signal for the fluid actuator other than the most delayed is generated based on the current position and the current speed of the most delayed fluid actuator detected by the position sensor, Based on the position target signal generating means, the first position target signal, and the current position of the fluid actuator detected by the position sensor, the fluid actuator is positioned at the position represented by the first position target signal. First position control means for outputting a control signal to the control valve, the speed target signal, Speed control means for outputting a control signal to the control valve so that the speed of the most delayed fluid actuator becomes the speed represented by the speed target signal based on the current speed of the fluid actuator being operated, Based on the third position target signal and the current position of the fluid actuator other than the latest delay detected by the position sensor, the position of the fluid actuator other than the latest delay is the third position target signal. And a third position control means for outputting a control signal to the control valve so that the position is represented by.

Further, in the fluid actuator tuning control apparatus, it is desirable that the overload detection means detects an overload when the opening of the control valve is equal to or larger than a set value.

In the fluid actuator tuning control device, the overload detection means may detect that the deviation between the maximum position and the minimum position of the fluid actuator exceeds an allowable deviation based on the output of the position sensor. It is desirable to detect overload.

Further, in the above fluid actuator tuning control device, the overload detection means is provided in a state where the deviation between the maximum position and the minimum position of the fluid actuator exceeds a set value based on the output of the position sensor. It is desirable to detect overload when the duration exceeds the set time.

[0009]

According to the first aspect of the present invention, when none of the fluid actuators is overloaded, each fluid actuator follows the first position target signal from the first position target signal generating means. It is controlled by the one-position control means via the control valve. In this case, since none of the fluid actuators is overloaded, the fluid actuator is tuned by the feedback control by the position sensor that detects the position of the fluid actuator, the first position control means, and the control valve. To be

On the other hand, when the overload detection means determines that one of the fluid actuators is overloaded, the speed target signal generation means determines the speed for the fluid actuator that is the most delayed based on the input set value. Generate a target signal. Then, the speed control means, based on this speed target signal and the current speed of the most delayed fluid actuator, controls the speed of the most delayed fluid actuator to be the speed represented by the speed target signal. To the control valve. In this way, by switching the controlled object of the fluid actuator most delayed due to the overload from the position to the speed, the fluid actuator most delayed is returned to the control state. If the most delayed fluid actuator is controlled according to the position target signal, even if the set speed becomes small on the way,
The control valve remains fully open and cannot be controlled.

On the other hand, for the fluid actuators other than the most delayed, the third position target signal generating means is based on the current position and the current speed of the most delayed fluid actuator detected by the position sensor. Then, the third position target signal is generated. This third position target signal assumes the current position of the most delayed fluid actuator and its position after a predetermined time from the current speed in order to cause another fluid actuator to follow the most delayed fluid actuator, This represents the assumed position. Then, based on the third position target signal and the current position of the fluid actuator other than the most delayed one detected by the position sensor, the third position control means causes the fluid actuator other than the most delayed one. The control signal is output to the control valve so that the position of is the position represented by the third position target signal.
By doing so, the other fluid actuator tracks and tunes to the most delayed fluid actuator. Moreover, since the fluid actuators other than the most delayed one are controlled by the third position target signal generated based on the current position and the current velocity of the most delayed fluid actuator, the tuning control is performed with high accuracy. . Further, since the fluid actuator that is most delayed due to overload shifts from position control to speed control, control can always be performed.

According to the second aspect, the overload detection means detects that the circuit of the control valve is overloaded when the circuit is equal to or larger than the predetermined value. That is, when the control valve is at the maximum flow rate, it is detected as an overload.

According to the third aspect, when the deviation between the maximum position and the minimum position of the fluid actuator exceeds the permissible deviation, it is detected as an overload. That is, when the deviation between the most advanced fluid actuator and the most delayed fluid actuator exceeds the permissible deviation, it is detected as an overload.

According to the fourth aspect of the present invention, when the deviation of the maximum position and the minimum position of the fluid actuator exceeds the set value, the overload is detected when the duration exceeds the set time. That is, when the deviation between the most advanced fluid actuator and the most delayed fluid actuator exceeds the set value for a predetermined period, it is detected as an overload.

[0015]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a diagram showing a mechanical structure of a tuning controller for a fluid actuator of this embodiment, and FIG. 2 is a block diagram showing a main part of the tuning controller for a fluid actuator.

In FIG. 1, 11 is a lower die fixed to a fixed platen 12, 13 is an upper die fixed to a movable platen 14, 15,
Reference numerals 16, 17 and 18 denote hydraulic cylinders as fluid actuators for moving the movable platen 14 up and down. Also, 25, 26,
27, 28 are position sensors composed of detection scales for detecting the tip positions of the piston rods of the hydraulic cylinders 15, 16, 17, 18 via the movable platen 14, 35, 36, 37, 3 respectively.
8 is a control valve for controlling the flow rate of oil supplied to the hydraulic cylinders 15, 16, 17, 18 respectively, 51 is a control panel, 52 is the position sensors 25, 26, 27, 28 from the hydraulic cylinders 15,
It is a controller that receives signals representing the tip positions of the piston rods 16, 17, 18 and outputs control signals to the control valves 35, 36, 37, 38.

The controller 52 operates as shown in FIGS. First, the control is initialized (step S1 shown in FIG. 3). Then, the control in the normal mode shown in FIG. What is the control of this normal mode? Which hydraulic cylinder 15, 16, 1
7 and 18 are not overloaded and the position feedback control is being performed. Next, it is determined whether the overload mode is set (step S3). Then, in the overload mode, a speed target for the overload axis is generated (step S7). On the other hand, if it is not in the overload mode, it is determined whether or not it is overload (step S
4). The determination as to whether or not this is an overload is performed as shown in FIG.

First, it is determined whether or not the opening command indicated by the signals to the control valves 35, 36, 37, 38 is the maximum value.
(Step S21 in FIG. 4). Any control valve 35,3
When the opening command to 6, 37, 38 is the maximum value, it is determined that the vehicle is in the overload state (step S22). Step S2
When it is determined in 1 that the opening command is not the maximum value, the most advanced hydraulic cylinder and the most delayed hydraulic cylinder are determined (step S23). That is, the fastest axis and the slowest axis are determined. Next, the deviation between the most advanced hydraulic cylinder and the most delayed hydraulic cylinder is calculated, and it is determined whether or not the deviation exceeds the set value (step S
24). That is, it is determined whether or not the inclination of the line connecting the tips of the fastest axis and the slowest axis exceeds the set inclination amount.
Then, if it is determined that the deviation does not exceed the set value,
(Step S24), the tilt allowance timer is initialized (step S25), and it is determined that the overload state is not present and is normal (step S26). If it is determined in step S24 that the deviation exceeds the set value, the process proceeds to step S27, and it is determined whether the deviation exceeds the allowable deviation. When it is determined that the deviation exceeds the allowable deviation, it is determined that the overload state is set (step S2).
8). If it is determined in step S27 that the deviation does not exceed the allowable deviation, the tilt allowable timer continues counting (step S29). Then, it is determined whether or not the tilt allowance timer has exceeded the set time (step S
30) If the tilt allowance timer does not exceed the set time, it is determined that the overload condition is not present and the normal condition is reached (step S31). If the tilt allowance timer exceeds the set time, Determines that it is in an overload state (step S32). That is, when the line that connects the tips of the hydraulic cylinders exceeds the set tilt amount and the tilt allowable timer exceeds the set time (steps S24, 30),
It is determined to be an overload state. That is, if there is a predetermined opening between the most advanced hydraulic cylinder and the most delayed hydraulic cylinder, and that state continues for a predetermined time, it is determined that the hydraulic cylinder is overloaded.

When it is determined in step S4 shown in FIG. 3 that the vehicle is not overloaded, the first position target signal is generated based on the set speed and the set position in the same manner as in the conventional example shown in FIG. (Step S5). Then, position control by feedback of all the axes, that is, all the hydraulic cylinders 15, 16, 17, 18 is performed in the same manner as the conventional example shown in FIG. 7 (step S6).

On the other hand, if it is determined in step S3 that the mode is the overload mode, or if it is determined in step S4 that the mode is the overload mode, an overload speed target signal for the hydraulic cylinder is generated (step S7). The speed target signal for the most delayed hydraulic cylinder in the overloaded state is generated based on the input set position and set speed. Based on this speed target signal and the current speed of the most delayed hydraulic cylinder, the control valves 35, 36, so that the speed of the most delayed hydraulic cylinder becomes the speed represented by the speed target signal. A control signal is output to 37 or 38 (step S8). In this way, by setting the control target of the most delayed hydraulic cylinder to the speed target represented by the speed target signal, the most delayed hydraulic cylinder in the overloaded state can be feedback-controlled. In other words, if the position of the hydraulic cylinder is the control target, the control valve will be fully opened. However, if the speed is used as the control target and the speed setting changes during operation (in particular, the setting will decrease). Part), the operating speed can follow the setting.

Next, based on the current position and the current speed of the most delayed hydraulic cylinder detected by the position sensor 25, 26, 27 or 28, the hydraulic cylinders 15, 16, 17, other than the most delayed hydraulic cylinder are detected. A third position target signal for 18 is generated (step S9). The third position target represented by the third position target signal is a position calculated by the hydraulic cylinder most lagging after a predetermined time from the present, based on the current position and the current speed. By setting the third position target as the control target for the hydraulic cylinders other than the one that is the second behind, even if one of the hydraulic cylinders is overloaded, the other hydraulic cylinder follows the hydraulic cylinder in the overloaded state. Is controlled so that all hydraulic cylinders are synchronized. Moreover, since this third position target is generated based on the current position and the current speed of the hydraulic cylinder that lags the most, it is an extremely preferable control target for performing synchronization.

This relationship is shown in FIG. In Fig. 6, the A axis is the most delayed in the overloaded state, and other B, C,
It is a diagram schematically showing that the D axis follows.

FIG. 2 is a functional block diagram of steps S7 to S10 of FIG. Based on the set speed and the set position output from the setting means 1, the speed target generating means 62 generates a speed target signal for the hydraulic cylinder 15 in the overloaded state, that is, the A axis. on the other hand,
The position of the hydraulic cylinder 15 is detected by the position sensor 25, and the current speed of the hydraulic cylinder 15 is detected by differentiating the output of the position sensor 25 by the differentiating means 64. The speed control means 63 calculates the deviation between the speed target from the speed target generating means 62 and the current speed from the differentiating means 64. The speed control means 63 outputs a signal representing this deviation to the control valve 35 to perform feedback control so that the hydraulic cylinder 15 moves at the speed target.

On the other hand, the third position target signal generating means 65 is
In response to a signal from the position sensor 25 indicating the current position of the hydraulic cylinder 15 and a signal from the differentiating means 64 indicating the current speed of the hydraulic cylinder, the third position target indicating the position of the hydraulic cylinder 15 after a predetermined time from the present. Generate a signal. The third position control means 66 calculates the deviation between the third position target signal and the current position of each of the B-axis, C-axis, and D-axis hydraulic cylinders 16, 17, and 18, and expresses this deviation. A signal is output to the control valves 36, 37, 38 to perform feedback control so that the B-axis, C-axis, D-axis hydraulic cylinders 16, 17, 18 are located at the third target position. In this way, based on the current position and the current speed of the hydraulic cylinder 15 that is most delayed in the overload state, the position of the hydraulic cylinder 15 after a predetermined time is assumed, and this position is set to the other hydraulic cylinders 16,
Since the third position target for 17 and 18 is set, highly accurate synchronization control can be performed even if there is an overloaded hydraulic cylinder.

[0025]

As is apparent from the above, according to the first aspect of the present invention, the overload state is detected by the overload detecting means, and the speed target which is the most delayed is generated by the speed target signal generating means. As the control target,
While performing feedback control by the speed control means, fluid actuators other than the most delayed fluid actuator are generated based on the current position and current speed of the most delayed fluid actuator, and the most delayed fluid actuator is generated. Third, which represents the position after a predetermined time
Since the third position control means performs feedback control with the target position signal as a control target, all fluid actuators can be tuned with high accuracy even if there is an overloaded fluid actuator.

According to the second aspect of the present invention, when the opening of the control valve is equal to or larger than the set value, it is detected as an overload.
The overload condition can be easily detected.

According to the third aspect of the present invention, when the deviation between the maximum position and the minimum position of the fluid actuator exceeds the allowable deviation, it is detected as an overload, so that the tuning is surely broken due to the overload. Can be detected.

According to the invention of claim 4, when the duration of the state where the deviation between the maximum position and the minimum position of the fluid actuator exceeds the set value exceeds the set time, the overload is detected. The overload condition can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a tuning controller for a fluid actuator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main part of the above embodiment.

FIG. 3 is a flowchart showing the operation of the controller of the above embodiment.

FIG. 4 is a flowchart showing an operation of detecting an overload state of the controller.

FIG. 5 is an explanatory diagram showing a state of the concept of conventional tuning control.

FIG. 6 is an explanatory diagram showing the concept of tuning control of the present invention.

FIG. 7 is a block diagram of a conventional tuning control device for a fluid actuator.

[Explanation of symbols]

15, 16, 17, 18 ... Hydraulic cylinders, 25, 26, 27,
28 ... Position sensor, 35, 36, 37, 38 ... Control valve, 52 ... Controller.

Claims (4)

[Claims] 1. A plurality of fluid actuators (15, 16, 17, 18) to be operated in synchronism, and a control valve (35, 36) for controlling the speed of each fluid actuator (15, 16, 17, 18). , 37, 38), a position sensor (25, 26, 27, 28) for detecting the position of each of the fluid actuators (15, 16, 17, 18), and each of the fluid actuators (15, 16, 17, 18) ) Is an overload detection means
(S4, S21, S27; S24, S30) and the overload detecting means (S4, S21, S27; S24, S).
When it is determined that none of the fluid actuators (15, 16, 17, 18) is overloaded based on the output of (30), the fluid actuators (15, 16,
First position target signal generating means (S) for generating a first position target signal for
5) and the overload detection means (S4, S21, S27; S24, S
When it is determined that any one of the fluid actuators (15, 16, 17, 18) is overloaded based on the output of (30), the most delayed fluid actuator (1
5) A speed target signal generating means (62, S7) for generating a speed target signal based on the input set value, and the overload detecting means (S4, S21, S27; S24, S).
When it is determined that one of the fluid actuators (15) is overloaded based on the output of (30), the fluid actuators (16, 17, 1) other than the one that is the most delayed
8) the third position target signal for the position sensor (25)
Third position target signal generating means (65, S9) for generating based on the current position and the current speed of the fluid actuator (15) that is the most delayed, detected by the first position target signal, and the position. Sensor (25, 26,
27, 28) said fluid actuator detected by
Based on the current position of (15,16,17,18), the fluid actuator (15,16,17,18) is moved to the first position.
A first control signal is output to the control valve (35, 36, 37, 38) so that the control valve is positioned at the position indicated by the position target signal.
Based on the position control means (3, S6), the speed target signal, and the current speed of the most delayed fluid actuator (15), the speed of the most delayed fluid actuator (15) is determined as above. The control signal is adjusted so that the speed indicated by the speed target signal is reached.
The speed control means (63, S8) that outputs to (35), the third position target signal, and the position sensor (26, 27,
28) based on the current positions of the fluid actuators (16, 17, 18) other than the most delayed one detected by
6, 17, 18) so that the position of the control valve (36, 3) is the position represented by the third position target signal.
7, 38) and a third position control means (66, S10) for outputting to the tuning control device for the fluid actuator. 2. The fluid actuator tuning control device according to claim 1, wherein the overload detection means (S21) is configured to control when the opening of the control valve (35, 36, 37, 38) is equal to or greater than a set value. A tuning controller for a fluid actuator, which is characterized by detecting that it is overloaded. 3. The tuning control device for a fluid actuator according to claim 1, wherein the overload detection means is used.
(S27) is based on the output of the position sensor (25, 26, 27, 28) and is based on the output of the fluid actuator (15, 16, 1).
7. 18) A tuning controller for a fluid actuator, which detects overload when the deviation between the maximum position and the minimum position exceeds the allowable deviation. 4. The tuning controller for a fluid actuator according to claim 1, 2, or 3, wherein the overload detection means (S24, S30) is the position sensor (25, 26, 2).
7, 28) based on the output of the fluid actuator (1
(5,16,17,18) is a fluid characterized by detecting overload when the duration of the state where the deviation between the maximum position and the minimum position exceeds the set value exceeds the set time. Actuator tuning controller.