JPH01176805A - Control method for single rod cylinder - Google Patents

Abstract

PURPOSE:To constitute a hydraulic servo system with high accuracy by varying a flow from a servo valve to a cylinder chamber according to the size of a pressure receiving area on the oil pressure supply side. CONSTITUTION:Provided that a pressure receiving area A1 is provided on the elongated side of a piston rod shaft 7 and a pressure receiving area A2 is provided, on the other side, it is detected every definite period, whether the oil pressure supply side is in a cylinder chamber 6 having pressure receiving area A1 or in a cylinder chamber 6 having pressure receiving area A2. And an oil pressure flow is controlled by varying a flow from a servo valve 13 to the cylinder chamber 6 according to the size of a pressure receiving area on the oil pressure supply side, and regarding a single rod cylinder as a rod cylinder having pressure receiving area A1 or A2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control method for a hydraulic control device, and particularly to a control method for supplying hydraulic pressure to a cylinder chamber.

(Prior art) Conventionally, in hydraulic servo systems that require high precision, the fifth
It has been common practice to avoid using a single-rod cylinder having a rod 3 extending outside the cylinder 1 from one side of a piston 2 sliding inside the cylinder 1, as shown in FIG. 1(a). In the case of a single-rod cylinder, the pressure receiving area of the piston 2 differs by the cross-sectional area of the rod 3 between the cylinder chamber 1afl1m and the cylinder chamber 1b side, and even if oil is supplied at the same pressure, sliding may occur depending on the direction of movement of the piston. The reason is that it is difficult to realize a highly accurate servo system because the speeds differ and the characteristics of the system change.

Therefore, in hydraulic servo systems that require high precision, the fifth
A double-rod cylinder, as shown in Figure (b), having rods 3, 3 extending outward from both sides of the piston 2 was used.

(Problems to be Solved by the Invention) However, when using a double-rod cylinder, in order to obtain the same cylinder stroke as a single-rod cylinder, it is necessary to obtain approximately 1.0 mm when the piston is in neutral compared to a single-rod cylinder.
The total length will be tripled. Furthermore, when comparing the rod operating range from the one rod tip to the other rod tip, the double rod cylinder needs to be about 1.5 times as long as the single rod cylinder.

Therefore, there is a problem in that a large space is required for installation, leading to an increase in the size of the servo system control device.

Furthermore, since the number of parts increases, the cost is also higher than that of a single rod cylinder.

The present invention has been made in view of the problems of the conventional example, and provides a control method for a single-rod cylinder that can realize a highly accurate servo system using a single-rod cylinder that is inexpensive and requires a small installation space. The purpose is to

(Means for Solving the Problems) In order to achieve the above object, the method of the present invention provides a single rod cylinder having a cylinder, a piston sliding inside the cylinder, and a rod extending from one side of the piston to the outside of the cylinder. and a servo valve that supplies hydraulic pressure to the cylinder chamber of the single rod cylinder,
The rod extension side of the piston is defined as a pressure receiving area A1, and the other side is defined as a pressure receiving area A2, and it is detected at regular intervals whether the hydraulic pressure supply side is a cylinder chamber with a pressure receiving area A1 or a cylinder chamber with a pressure receiving surface MtA2. Then, the flow rate flowing from the servo valve to the cylinder chamber is changed depending on the type of pressure receiving area on the oil pressure supply side, and the single rod cylinder is connected to the pressure receiving area MA.
It is characterized in that the hydraulic flow rate is controlled by treating it as a double rod cylinder having a pressure receiving area A2 or a pressure receiving area A2.

Hydraulic pressure is supplied from the servo valve to the cylinder chamber by moving the spool of the servo valve in response to a current signal from the controller and changing the opening area of the boat leading to the pump.

Said current signal as a control input is applied to the state feedback vector f set for the respective pressure receiving area AI, A2 of the piston of the single rod cylinder 1. It is determined by the product of fA2 and the state quantity of the control system. If the state quantity is expressed as a state variable vector X and the state feedback vector is a winnow, then the control human power U is determined by tl=1×. The state feedback vector # is designed to minimize the quadratic evaluation function, f = −+r
lb IP.

Here, P is PA+AP -1Plb +r lb I
This satisfies Riccutti's matrix equation of P+1Q=0.

1 is a weight matrix of the control input U, which prevents reaching an unrealizable solution where the input power becomes infinite.

Q is a weight matrix for state variables, and by assigning large weights to state variables that are not controlled accurately, various state feedback vectors can be designed.

A, 1b is a matrix determined from the characteristics of the control system. For example, in a vibration damping device that damps the vibration of a structure by operating the pressure receiving area of a cylinder or an additional mass on the structure, These are the mass of the additional mass, the spring constant, the damping constant, etc. Therefore, with these matrices, the pressure receiving area 1
A state feedback vector suitable for ^1 or pressure receiving area f82 can be designed, and using this state feedback vector, a single rod cylinder can be controlled as a double rod cylinder whose pressure receiving area is equal to the respective pressure receiving area.

(Function) According to the method of the present invention, since it is possible to perform control using a single rod cylinder as if using a double rod cylinder whose pressure receiving area is equal to each rod cylinder, highly accurate control can be performed regardless of the direction in which hydraulic pressure is supplied to the cylinder chamber. Let's do it.

(Example) An example of the present invention will be described with reference to the drawings.

1 to 4 show the case where the method of the present invention ζ is applied to a vibration damping device. A vibration damping device is a device that installs an additional mass that can be reciprocated on top of a structure, and operates this additional mass to apply a reaction force to the structure and reduce the vibration of the structure.

FIG. 3 shows a side view of the vibration damping device installed on the top of the structure, and FIG. 4 shows its plan view.

A rectangular parallelepiped additional mass 5 is installed on the top of the structure 4. A single-rod cylinder 6 is attached to the circumferential surface of each additional mass 5, and one end of a rod shaft 7 of each cylinder 6 is connected to a wall 8 erected on the structure 4 so as to surround the additional mass 5.

The pressure receiving areas on both sides of the piston of one rod cylinder 6 differ by the cross-sectional area of the rod shaft 7, with the smaller area side being AI,
The large area side is A2.

A hydraulic unit 9 that supplies oil to the cylinder 6 is installed in the center of the additional mass 5. There is a car at the bottom of additional square 5.
1a10 is attached, and the additional mass 5 can be freely moved on a horizontal plane surrounded by a wall 8 depending on how oil is supplied to the four cylinders. Further, the horizontal surface surrounded by the wall 8 reduces frictional force, making it easier for the wheels 10 to move.

FIG. 1 shows a model diagram of an embodiment of the present invention.

An additional mass 5 movable by a cylinder 6 is attached to the upper part of the structure 4. In Figure 1, the additional mass 5 is 1 for simplification.
I made it move using the cylinder of the book. Furthermore, in the actual device, the structure 4 and the additional mass 5 vibrate in the horizontal direction, but in the model diagram, they vibrate in the vertical direction.

The structure 4 and the additional mass 5 are provided with displacement detection means 11a, 1111. Speed detection means 12a
, 12b are provided, and the displacement of the structure 4 x 7 and the displacement of the additional mass 5 x 2 are detected every pulling time as state quantities. The displacements X, , and X are set to take positive and negative values, with O being the state in which the structure 4 and the additional mass 5 are stationary. Also x
, j2 also take positive or negative values depending on the direction of movement of the additional mass.

Displacement detection means 11a, llb and speed detection means 12a
, 12b is input to the controller 2, where the relative displacement between the structure 4 and the additional mass 5 x 2' (X2 X+)
Then, calculate the relative velocity cross 2.

The controller Z has two types of state feedback vectors for controlling the one-rod cylinder 6 on the assumption that there are two double-rod cylinders equal to the pressure-receiving area A1 and the pressure-receiving area A2 of the piston. 2 is stored in the state feedback vector fAct or the state feedback vector f for large areas. This state feedback vector creates an optimal regulator system using both rod cylinders with a pressure receiving area of A1 or A2, and changes the state feedback vector f° to 1. Find f゛82. And this state feedback vector Go^1. A state feedback vector corresponding to the oil pressure supply side is selected from f'A2 and the state feedback vector O in which all elements are O.

511 state feedback plots” = (f,
,f2,f,,f,>f, ,f2,f, ,f
, respectively, and add each value using a calculator,
Control human power u = f LXI + - f2x, 10 f, X,
Obtain 10 f4 moxibustion 2.

This control human power U is calculated by detecting the state quantity at every fixed sampling time. Then, depending on the sign of this control human power U, the state feedback vector 1°A1 or 1''A2 at the next sampling time is selected.

When the state feedback vector changes at each sampling time, that is, when the sign of the control input U differs at each sampling time, the state feedback vector selects O to prevent the piston from fluttering, and a signal to close the servo valve 13 is output. do.

A control input U output from the controller Z is adapted to energize a solenoid 15 that slides a spool 14 of a servo valve 13. Among the three boats provided on the hydraulic pressure supply side of the servo valve 13, the center boat 16 is connected to the pump P (
The left and right boats 17 and 18 each communicate with a tank T (not shown). Servo valve 13
2 boats 20 are each connected to the spool 1 by the 6 control manual U which communicates with the chamber of the cylinder 6.
4, the piston slides by changing the opening area with the boat 16 to which hydraulic pressure is supplied, and changing the flow rate of oil flowing into the cylinder chamber on the pressure receiving area A1 side or the cylinder chamber on the pressure receiving area A2 side. Control the speed.

In the model diagram shown in FIG. 1, oil leakage from the seal portion of the cylinder 6 is taken into consideration, and the flow of oil is modeled using throttles R, R2 and a tank.

When the structure 4 receives an external force such as wind or an earthquake, it begins to sway upward in FIG. 1 (upward direction is rightward in the actual device). , 12b, and inputs this signal to the controller Z to calculate the control human power U.

Control input U energizes solenoid 15 and servo valve 13
The spool 14 of the boat is slid, for example, in the right direction in FIG. 1, to obtain an opening in the boat according to the control input. When the spool 14 slides to the right, the boat 17 is closed, and the oil from the pump P flows into the boat 16, the boat 20, and the lower cylinder chamber, pushing up the piston in the cylinder 6, and the oil in the upper cylinder chamber flows into the boat 16, the boat 20, and the lower cylinder chamber. 19, tank T via boat 18
guided by.

As a result, the rod 7 of the cylinder 6 moves, and the additional mass 5 is moved upward, which is the same side, behind the movement of the structure 4 (Figure 1 is a model diagram, so the rod 7 in the vertical direction moves). ing).

When the sign of the control force U is reversed, the spool 14 of the servo valve 13 slides in the opposite direction, and oil is supplied to the opposite cylinder chamber to reduce the sliding speed of the piston 2, and then the piston 2 and the additional Move square 5 in the opposite direction. Therefore, the vibration of the structure 4 is reduced by applying a control force to the structure in the opposite direction to the external force by the reaction force generated by moving the additional mass 5.

At this time, the controller Z
Since the state feedback vectors selected in are different,
Control inputs for the same state quantity are different, and optimal control is performed for each. If the state quantity as an external factor is the same, cylinder 6 under the same situation despite the difference in pressure receiving area.
The piston can be slid.

In this embodiment, a state feedback vector suitable for the situation is selected from a set of state feedback vectors depending on which piston surface of the pressure receiving area A1 or the pressure receiving area A2 is to be supplied with hydraulic pressure. A2
By storing a plurality of state feedback vectors each having a different damping effect and selecting one of the plurality of state feedback vectors depending on the position of the piston, even more precise control is possible.

Next, the individual state feedback vectors ゛=(f,
, f2, f, , f,) will be explained.

1. Differential equation of the system The external force is F, the force acting between the structure 1 and the additional mass 2 is U,
*The mass of pickle 1 is Ml, the damping constant of structure 1 is CI,
Assuming that the spring constant of structure 1 is 1, the equation of motion of the structure is F−U−~11×1−tC+XI+KI
XI
i1) becomes.

If *m of the additional mass is M, the equation of motion of the additional mass is IJ-M2Xl (2
＞That is.

The pressure receiving area of the cylinder is A, the pressure of the cylinder at the winter solstice is p,
p, the damping constant of the cylinder is α, and the spring constant of the cylinder is! Assuming that the cylinder output and frictional force are zero, the control force is u-A (P, -P, )-α(x+ -XI >-
+ (x+ −X, > (3)).

The equation for continuity in a cylinder is: Q5 is the flow that flows into the cylinder from the servo valve, Q6 is the flow that flows out from the cylinder to the servo valve, and Q5 is the flow that leaks from each cylinder to the outside.
, Q4, from the 10th lower cylinder chamber to the upper cylinder! Let Q be the flow rate leaking to RV+ / -Q+ -A (XI -x + ) -
Qs −Qs (4) PI V2 /ni−
−Or=A (x r −x + )−α 10, (5).

In a model that takes into account the flow from the cylinder chamber, R,
If R is the aperture coefficient, the aperture formula is Q, -R,P.

Q, -R,P.

Q, −R, (P, −P, >
(6) becomes.

Next, consider the characteristics of the servo valve.

Let the rated current of the servo valve be
(7) Q, −(i, /[r)
QrF: Face (8) If i<Q, then o, -,'tr >orF (9) a, -<
I/rr>orlT possible-P,)/3 pieces
(1o).

2. Linearization of differential equations Equations (7) to (10) are transformed into equilibrium points (P, -P, .p2-p,
. Linearize in the vicinity of i-i, ), take ΔF, treat ΔF as a disturbance, and write the equation of state% (
12) Expressed as. In this case, the matrices A and - are respectively 4 rows and 4 columns and 4 rows and 1 column, and each element of the matrix is as follows.

A1, -〇 △, 1-O Alx-1 I4-0 A1, -〇 A2, -〇 A, 4-O A2. -1 8□--ni, /M.

△in −Kl /! Vl+ △n -C+ /'MI A,, -(1/M, ') (2A', / (β+R
+ +2R1>+Ct), -Kl/Ai.

A, --Kl (Ml2M,),'\1. ＼4゜A、
-C,,/M.

A44-- ((M, +M, ) /M, M, )
(2A' / (β + R5 engineering 2R3) engineering C,) bll
-0 b,, -Q bkai1--(1/M,)(2Aα7/(β+R,+2R
,))b%, -[M, +M, , /M, M, )
(2Aα/(β+R, +2R,)) Here, if the output vector y is defined as, the output equation becomes as follows.

-Ct 3, Ill-suitable regulator design (12) In the control system expressed by equation (14), design an R-suitable regulator that minimizes the PIaiF311 equation (15).

Control input (Since 1 is a scalar quantity, the input weighting coefficient r
is also a scalar (6).

When the weight matrix Q for the state variables is set, the evaluation function J can freely design IIItil systems ranging from large to small allocation effects by increasing the weighting coefficient q corresponding to .

The optimal input U° is the optimal feedback vector d(r,
, r, , r, , r4) is expressed as follows (u''-Δi'), u@, , r# r wf , Δx
, +4. Δx, '+j, Δx, +r, Ax, '
(18) A block diagram of the vIIII system is shown in FIG.

The optimal feedback vector t @ that minimizes J expressed by equation (15) is given by the general formula %. However, P is a positive definite only solution that satisfies the following Norikatti matrix equation.

PA-', A P-P Ib r IbpM)-o
(20) When setting the above-mentioned state feedback vector, set the pressure receiving area A to each pressure receiving area A1
Alternatively, if the pressure receiving area is calculated as A2, the control system can be configured using a double rod cylinder having the pressure receiving area A1 or the pressure receiving area A2.

In the above embodiment, the state variable vector is the displacement of the structure 4 x5, the relative displacement of the additional mass 5 with respect to the structure 4 x 2'
, the velocity i1 of the structure 4, and the relative velocity between the structure 4 and the additional mass 5 x 2, but other vibration-related variables and hydraulic cylinder control variables may also be considered as state quantities. .

In other words, the displacement of the structure 4 at the vibration damping device mounting position×
7. Displacement of additional mass 5 x 2, Displacement of the bottom of structure 4 or the ground XO, Relative displacement of additional mass 5 with respect to structure 4 x
2. The pressure in each cylinder chamber is p1.02%, and the displacement of the spool 14 of the servo valve 13 is It is appropriate to do the following:

(a) When n=(XI X2 XI X2), ru
”)dt ru2)d is effective.

(d) Y=(XI X; XI X2'pI 02 )
When ru2) dt When ru'> dt or rtl'') dt or (Effects of the Invention) As described above, the present invention includes a cylinder, a piston sliding inside the cylinder, and a piston from one side of the piston. In a hydraulic control device consisting of a single-rod cylinder having a rod extending outward from the cylinder and a servo valve that supplies hydraulic pressure to the cylinder chamber of the single-rod cylinder, the rod-extending side of the piston is defined as a pressure-receiving area A1, and the other side is a pressure-receiving area A1. The pressure receiving area is A2, and it is detected at regular intervals whether the hydraulic pressure supply side is a cylinder chamber with a pressure receiving area A1 or a cylinder chamber with a pressure receiving area A2, and depending on the type of pressure receiving area on the hydraulic pressure supply side, the cylinder is moved from the servo valve to the cylinder chamber. By changing the flow rate flowing into the chamber,
The single rod cylinder has a pressure receiving area A1 or a pressure receiving area A2.
Since the hydraulic flow rate is controlled by treating it as a double-rod cylinder with a single-rod cylinder, it can be controlled using a single-rod cylinder as if it were a double-rod cylinder whose pressure-receiving area is equal to that of each rod cylinder, allowing highly accurate control regardless of the direction in which the hydraulic pressure is supplied. can be done.

Therefore, a highly accurate hydraulic servo system can be constructed using a single rod cylinder that is inexpensive and requires a small installation space.

[Brief explanation of the drawing]

FIG. 1 is a model diagram of a vibration damping device showing an embodiment of the present invention;
Figure 2 is a block diagram of the control system, Figure 3 is a side view of a vibration damping device using the present invention, Figure 4 is a plan view of the vibration damping device, and Figures 5 (a) and (b) are single rod cylinder and It is an explanatory view showing a double rod cylinder. 4...Structure 5...Additional mass 6...Cylinder 7...Rod shafts 11a, 11b...Displacement detection means 12a
, 12b... Speed detection means Z...
・Controller December 30, 1988 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] A single-rod cylinder having a cylinder, a piston that slides inside the cylinder, and a rod that extends outside the cylinder from one side of the piston, and a servo that supplies hydraulic pressure to the cylinder chamber of the single-rod cylinder. In a hydraulic control device comprising a valve, the rod extension side of the piston is a pressure receiving area A1, the other side is a pressure receiving area A2, and whether the hydraulic pressure supply side is a cylinder chamber with a pressure receiving area A1 or a cylinder chamber with a pressure receiving area A2. is detected at regular intervals, and the flow rate flowing from the servo valve to the cylinder chamber is changed depending on the type of pressure receiving area on the oil pressure supply side, and the single rod cylinder is regarded as a double rod cylinder having a pressure receiving area A1 or a pressure receiving area A2. A control method for a single rod cylinder, characterized in that the hydraulic flow rate is controlled by the hydraulic flow rate.