JPS63103302A - Feedback controller - Google Patents

Abstract

PURPOSE:To improve controllability of a feedback controller by applying a deviation control signal which is under feedback control to a compensating circuit kept under a waiting in case two types of compensating circuits are provided. CONSTITUTION:A feedback controller for flow rate and pressure of a variable capacity type hydraulic pump contains the feedback control systems 8 and 9 for flow rate and pressure respectively, 1st and 2nd changeover switches 17 and 18 for both systems 8 and 9, a flow rate control compensating circuit 10, a pressure control compensating circuit 11, and a deviation value deciding circuit 20. Then the flow rate or pressure deviation control signals received from a subtracter circuit 5 are switched by the switch 17 and delivered to both circuits 10 and 11 by a control level unifying means 22. In such a constitution, the flow rate deviation control signal is compensated by the circuit 10 and supplied to an operating element 2 at the time of feedback control for flow rate. While the flow rate deviation signal is applied to the circuit 11 kept waiting from the means 22. Thus the waiting control signal is kept at a low level for the circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a feedback control device for a variable displacement hydraulic pump, etc., and in particular to a feedback control device having a feedback control system equipped with a compensation circuit for improving the characteristics of the system. Regarding improvements.

(Prior Art) Conventionally, for example, in the feedback control system of a variable displacement hydraulic pump,! ! III'a A pump swash plate as a target, an operating means such as an electric circuit or a hydraulic actuator for operating the cough pump swash plate, and a deviation control signal having a value equal to the deviation between the feedback amount and the target value to this operating means. By controlling the inclination angle of the pump swash plate in response to this control signal, the oil flow rate and action on the actuator connected to the hydraulic pump are controlled. Feedback of control values such as pressure to target valuesf!
I control.

By the way, in the above-mentioned feedback control system, a compensating circuit that improves the characteristics (transient response) of the control system is generally used, and the characteristics of the control system are almost improved. We are trying to make it happen as planned. For example, when this compensation circuit controls both the oil flow rate and pressure as described above, the width of the loop is different between the flow rate control system and the pressure control system. Since the compensation constants for compensation are different from each other, a "C-compensation circuit" is required for both the flow rate control system and the pressure control system, and the connection of the compensation circuits for both of them is changed as necessary. During feedback control of a train, the flow rate is 4th of control.
Control signal output from the circuit to the control element to the operation element
It is connected to the control loop of the pump swash plate by intervening in the J path, while at the same time, when the pressure is controlled by pressure I, it is necessary to switch and connect the compensation circuit for pressure control C to the control loop of the pump swash plate. .

(Problems to be solved by the invention) However, when two or more compensation circuits are provided as described above,
For example, during flow rate feedback control to which a compensation circuit for flow rate control is connected, other compensation circuits for pressure control that are on standby are in an open state, and the initial operation of this pressure control is usually This is carried out in the middle of the transmission path of the pressure deviation control signal from the circuit to the operating element, and therefore one ball force deviation control from the control element is input to the standby compensation circuit, but this control The value of the pressure S arrival signal is a large value during non-feedback control of pressure, and the value of the pressure S arrival signal is a large value during non-feedback control of pressure,
The elevation signal level becomes large, and as a result, the next time you switch from the flow control button to pressure control, the large standby will occur.
Due to the surface signal level, pressure overshoots and undershoots occur at the beginning of switching! There is a drawback that the In property is lowered.

The present invention has been made in view of the above.The purpose of the present invention is to, when two types of compensation circuits are provided, provide a compensation signal for the deviation during feedback control to the standby compensation circuit. , the standby control signal level of this standby compensation circuit is made equal to that of the active compensation circuit, and overshoot and undershoot are prevented during feedback control switching transition, thereby suppressing w+! The aim is to improve the

(Means for Solving the Problems) In order to achieve the above object, the configuration of the present invention, as shown in FIG.
and a control element (5) that individually outputs (to) differential control signals in two or more states to the operating element (2). ), the target is a feedback control @ device that performs feedback #I control of the state above 2JX such as flow rate and pressure. and a compensation circuit (101, (1i) for improving good characteristics corresponding to each state feedback system), and a control necessity detection means (20) for detecting when feedback control of each state is necessary; Receives the output of the control necessity detection means (2o) and provides feedback i!II of the state in which control is necessary.
The above-mentioned compensation circuit (10) or (11) corresponding to the I control system is the control target 1) 7i! A switching means (21) is provided in the I control loop. Furthermore, during the feedback control of the control element (5) above,
That deviation of the torso signal during other special effects! This configuration includes control level equalization means (22) for applying to the habituation circuit (11) or (10).

(Operation) With the above configuration, in the present invention, one controlled object 1)
When the feed varactor J is controlled in a predetermined state (for example, flow rate), the compensation circuit (10) for flow rate control is switched and connected to the control loop of the controlled object (1) by the switching means (21), and the control element <5>7) Flow rate deviation fi1 of
1 control signal has been compensated by the compensation circuit (10) for flow rate control, it is input to the operating element (2), and the above control signal (1) is adjusted to 9 J m. Therefore, the characteristics of the flow i feedback control system are realized to approximately the desired values, and the flow rate converges approximately to the target value.

In this case, other standby (e.g. for pressure control) compensation circuits (
11) is given the flow rate deviation control signal of the flow rate feedback layer J'm by the control level equalization means (22), and since the value of this flow rate deviation control signal is small, the waiting R1h
lJ5 signal level is kept low.

As a result, when the feedback of another state (for example, pressure) is started next time, the pressure control compensation circuit (11) is activated. 10 Even if it is connected to the -j control loop of target (1), the compensation circuit for control of the current flow rate (10)
Pressure feedback and control will start at a control signal level equivalent to
No force overshoot or undershoot occurs.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a feedback control system H for the flow rate and pressure of a variable 8-volume hydraulic pump. In the figure, 1) is a single l! with feedback control of both flow rate and pressure. +lJ l vs. oil,
The pump swash plate (2) of the mouth pump is an amplifier circuit as an operating means for adjusting the inclination angle of the pump swash plate (1), and the pump swash plate (2) includes a flow rate and pressure Each deviation! 1iIII control signal (described later) is amplified and the pump swash plate (
A main amplifier <2a) which outputs to 1) is provided.

In addition, (3) is the inclination angle of the pump swash plate 1), that is, the swash plate angle for detecting the oil discharge flow rate, and (4) is the actuator (not shown) that receives oil supply from the pump swash plate (1). (5) a pressure sensor for detecting the working pressure of oil at (5);
receives the output signal of the swash plate angle sensor (3) and detects the angular deviation between the actual inclination angle value of the pump swash plate (1) and the target inclination angle corresponding to the target flow rate, that is, the flow rate deviation.
A control element consisting of a subtraction circuit (5a) and a second reduction circuit (5b) which receives the output of the pressure sensor (4) and reduces the pressure deviation between the actual working pressure value of the oil and its target value. a subtraction circuit (5a), the subtraction circuit (5) has a first subtraction circuit (5a) with a control signal and a voltage signal).
The pressure difference control signal (voltage signal) from the second reduction circuit (5b) can be outputted to the amplifier circuit (2) via the inverting amplifier circuits (6) and (7), respectively. 2) is the flow rate deviation I! When the Ill8iI signal is received, the flow rate feedback control system (8 ), and the amplifier circuit (2) also serves as a subtraction circuit (5).
When a pressure deviation ~Lm signal is received from , the inclination angle of the pump swash plate (1) is adjusted according to the pressure deviation ~ja signal value.
Pressure feedback control system (9) that adjusts the daily force of oil by adjusting the discharge flow rate.
).

Furthermore, (10) is the IT feedback control system (8
) Compensation circuit for flow @ control in which the compensation constant is appropriately adjusted to improve the characteristics (frequency response), (11) is similarly compensated to improve the characteristics of the pressure feedback III system (9) The compensation circuits (10) and (11) each have a first resistor (R1) and a first resistor (R1), as shown in detail in FIG. Phase detection for improving response from a parallel circuit with one capacitor (C+);
It consists of a loop gain circuit (13) for one-line circuit power with a capacitor <02> and a booster (14), and for the former flow rate control, an inverted feedback control system is used. (8) has a relatively narrow loop system that directly feeds back the inclination angle from the pump swash plate (1), whereas in the latter pressure control system, the pressure feedback control system (9) is used for pump swash plate (1). Since it constitutes a wide loop system including the oil supply passage from the plate (1) to its connected actuator, each compensation constant for flow control and pressure control is selected to be different from each other. There is.

Then, both the compensation circuits (TO) and (il) have inverting amplifier circuits (15) and (1) on the subtraction circuit (5) side, respectively.
61 are connected in series, and are connected in parallel to each other, and first and second changeover switches (17) and (18) are connected to both ends of the parallel circuit, respectively. The first changeover switch (17) on the subtraction circuit (5) side switches both the compensation circuits (10) and (11) to the subtraction circuit (5).
The first subtraction circuit (5a) side and the second reduction circuit < 5! The second selector switch (18) is a '4 compensator circuit (1.7J) for controlling the flow rate of 1lIII.
10) and a compensation circuit (11) for five-force control are selectively connected to the amplifier circuit (2).

In addition, (20) is a deviation amount determination circuit, and the deviation amount determination circuit (20) receives the flow rate deviation control signal from the fourth sub-circuit (5a) of the above-mentioned twilight circuit (5), and 2 Receives the pressure deviation control signal from the frame reduction circuit <5h), and from the deviation between the two (6), feedback @(+:
The flow fork determines the control system with a large sensor output) and functions as a means for detecting when five-force feedback control is necessary. When IJ elevation is required, the first and second selector switches (17), (
18) to the flow rate side, and when pressure control is required, a switching signal is output to switch them to the pressure side.

Therefore, the first and second changeover switches (17), (
i8) receives the output of the deviation amount \i1 constant circuit (20) from the common part of each feedback control system for flow rate and pressure, that is, from the back reduction sieve circuit (5) of the control loop of the pump swash plate (1)! ! In the middle of the output path of each deviation control signal to @circuit 2), when flow rate control is required, the compensation circuit (10) corresponding to the suspension feedback control system is
) to the control loop of the pump swash plate 1), and when pressure control is required, four inertia circuits (11) for pressure control corresponding to the pressure feedback control system are connected to the pump swash plate 1). ) constitutes a switching means (21) which is switchably connected to the control loop of the control loop. In addition, after switching and selecting each difference control signal of flow rate or pressure from the reduction circuit (5>) by the switching operation of the first changeover switch (17), this selected deviation control signal is applied to the flow rate or pressure. Both compensation circuits (Itl)
, (11), when feedback controlling the flow rate (or pressure) of the pump swash plate (1) by the Makoto 9 circuit (5), the deviation control signal of each flow rate (or pressure) is input to the other standby. A control level equalization means (22) is configured to apply pressure (or flow rate) to the compensation circuit (il) (or 10) for one bullet.

Therefore, in the above embodiment, the swash plate angle sensor (3
) The inclination angle (flow rate) signal of the pump swash plate <1) detected by the pressure sensor (4) and the oil working pressure signal from the hydraulic pump detected by the pressure sensor (4) are each constantly input to the subtraction circuit (5). The subtraction circuit (5,) constantly calculates the deviations between the detected values of flow rate and pressure and their respective target values.
When the deviation amount determination circuit (20) determines, for example, that flow rate control is necessary based on these deviation control signals, the first and second changeover switches (17) and (18) are respectively set to the meteor side. By switching, the compensation circuit (10) for flow rate control is connected to the 94 control loop of the pump swash plate 1), and the flow rate deviation of the first reduction circuit (5a) of the subtraction circuit (5) is j The signal is this flow rate! The input signal is input to the amplifier circuit (2) via the compensation circuit (10) for 1, and the inclination angle of the pump swash plate (1) is feedback-controlled by this amplifier circuit (2), so the compensation for the Toi flow rate υI is inputted to the amplifier circuit (2) via the compensation circuit (10) for With the circuit (10), the characteristics of the flow rate feedback control system are realized to approximately the desired value, and the discharge flow rate of oil from the hydraulic pump is adjusted to the target value.

Except for that, the first changeover switch (17) is switched to the flow rate side, and both compensation circuits (10) and ( 11
), and at the same time the flow rate deviation control signal of the first culm reduction circuit (5a) is output to the flow rate control compensation circuit (10), the standby pressure control compensation circuit (11) ), so the compensation circuit for pressure control (1
The standby control voltage level at step 1) becomes equivalent to the compensation circuit (10) for the active flow rate IVJ. As a result, the next time pressure control is required and pressure feedback control is started, the working pressure will smoothly move toward its target value without overshooting or undershooting at the beginning. It will converge to .

The above operation is the same even during pressure control, and during pressure control, the first and second changeover switches (17), (
18) respectively switch to the pressure side, and the pump swash plate (1) ~
Since the pressure control compensation circuit (11) corresponding to the pressure feedback BL IEI system is connected to the control loop, the pressure feedback control is performed with almost the desired burst, and the working pressure of the oil is kept at the target value. In addition, the pressure deviation control signal of the pressure reduction circuit 5) is inputted to the compensation circuit (11) for the first side of the pressure sensor as well as the compensation circuit (10) for flow fiffi control. Since the standby control W voltage novel of this compensation circuit (10) for flow control is equivalent to the compensation circuit (11) for J control of the second article, when the flow rate feedback control is switched next time, Also, the discharge f:, φ of the hydraulic pump smoothly converges to the target value without overshoot P or undershoot.

Although the above embodiment describes the case where the flow rate and working pressure to the actuator connected to the hydraulic pump are feedback-controlled, the present invention is not limited to this, and the above-mentioned PM and pressure may also be subjected to horsepower control. It goes without saying that it can be applied in the same way even if it is added, and it can also be applied not only to #Jl of hydraulic pumps but also to control of Tanabata etc., in short, feedback control of two or more states for a single controlled object The same applies if the

<Effects of the Invention> As explained above, according to the feedback control device of the present invention, when a compensation circuit for improving characteristics is provided for each feedback control system in a state on 2jX for an intermediate controlled object, During feedback control of a predetermined state, the corresponding compensation circuit is connected to the control loop of the control loop, and the control deviation signal being controlled is given to the other compensation circuits that are on standby to adjust the standby control signal level. Since the control signal level is set equal to the control signal level during sys- tation, even when the control is switched to feedback control in another state, the state after the switch can be maintained without overcoating or undershooting. It is possible to smoothly converge to the target value.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a block diagram when applied to a 5:1 feedback system for oil flow rate and pressure from a hydraulic pump, and Fig. 2 shows a specific configuration of a compensation circuit. It is an electrical circuit diagram. (1)...Pump swash plate, (2)...! ! 1 width circuit,
(3)... Swash plate angle sensor, (4)... Pressure sensor,
(5)... reduction circuit, (8)... flow rate feedback control system, ku)... 1 mouthful feed back control system,
(10)...Automobile 1III official compensation circuit, (11)・
...Pressure control compensation circuit, (12)...Phase lead circuit, (13)...Phase delay circuit, (17)...First changeover switch, (18)...Second changeover switch, (20
)...Difference i judgment circuit, (21)...Switching means, (
22) Control level equalization means. Patent Applicant Daikin Industries, Ltd. Agent Patent Attorney Former 1) Hirokichi', - +,,,,- I9-J++-''

Claims (1)

[Claims] (1) A single controlled object (1), an operating element (2) that operates the controlled object (1), and deviation control signals in two or more states are individually output to the operating element (2). Control element (5)
A feedback control device configured to perform feedback control of two or more states on the controlled object (1), comprising: a characteristic improvement compensation circuit corresponding to each state of the feedback control system; 10), (11), a control necessity detection means (20) that detects when feedback control is necessary for each state, and a control necessity detection means (20) for detecting when feedback control is necessary for each state.
0) and switching means (21) for switchingly connecting the compensation circuit (10) or (11) corresponding to the feedback control system in a state requiring control to the control loop of the control object (1); At the same time, during feedback control of the controlled object (1) by the control element (5), the deviation control signal is transmitted to another standby compensation circuit (11) or (10).
).) A feedback control device characterized by comprising: control level equalization means (22) for providing control levels to