JPH0293101A - Operation control device for hydraulic actuator etc. - Google Patents

Abstract

PURPOSE:To improve control accuracy by applying increase/decrease correction to a final control amount supplied from a feedback control means to an operation material supply control means in response to the operation rate of an actual operation amount to an operation target value. CONSTITUTION:An operation control unit 10 calculates the deviation DELTAd=i-d between an operation target value i set by an operating part 11 and a feedback amount d measured by a control amount measuring part 8 and makes an increase/decrease correction to control amounts EA, EB based on a correction control amount DELTAE corresponding to the deviation DELTAd. Then, an operation rate K of the actual feedback amount d to the operation target value i in a previous period is calculated and a final control amount EB is calculated by multiplying the correction control amount DELTAE under a standard temperature 60 deg.C by K. Then, a hydraulic actuator 1 is driven through electro-magnetic open/close valves 7A, 7B and a change over valve 2 for the position and direction of control cylinders 4, 3. Thus, the reponsiveness and control accuracy for feedback control are extremely improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an operation control device for an i+t+ pressure actuator such as a hydraulic cylinder or a similar actuator.

(Prior art) For example, the i
Hydraulic flicks are often used as actuators for various hydraulic equipment such as +1+ pressure-operated crane vehicles. Among these 411-pressure nolinders, for example, hydraulic cylinders for remote control, hydraulic pressure from an oil pump (hydraulic pump) is generally transferred to the hydraulic oil chamber side or the return chamber side depending on the amount of opening/closing via an electromagnetic opening/closing valve. The operating amount of the hydraulic cylinder (cylinder rod (or operation stroke amount of the spool) is controlled according to a preset operation target value (operation target value) (see the specification of Japanese Patent Application Laid-Open No. 55-21309).

(Problem to be Solved by the Invention) Incidentally, the operating stroke amount of the above hydraulic equipment within a unit time is the amount of oil supplied into the hydraulic oil chamber or the amount of oil from the hydraulic oil chamber within the unit time. Although determined by the discharge amount, the amount of oil supplied or discharged within the unit time varies greatly depending on changes in the viscosity of the oil itself.

Therefore, if the ambient temperature changes due to, for example, changes in the outside temperature, changes in solar radiation to the hydraulic pipes, or the passage of operating time, the operating target value (operating target value) will eventually be assumed to be constant. However, the stroke amount on the side of the device that actually operates (the pressure cylinder) will have a different value. Therefore, there is a problem that the operation cannot be controlled in accordance with the operation target value set by the operation control section having the operation target value setting function.

(Means for Solving the Problems) The present invention has been made with the aim of solving the problems as described above. a predetermined actuator configured using an actuator operating substance; a target value setting means for setting an operation target value of the predetermined actuator; an actuating substance supply control means for supplying a corresponding amount of actuating substance; and an actual actuation amount for detecting the actual actuation amount of the actuator that is actually operated in response to the amount of actuating substance supplied by the actuating substance supply control means. a detection means; and a feedback control means for feedback-controlling the working substance supply control means according to the deviation between the actual working amount detected by the actual working amount detecting means and the working target value set by the target value setting means. In an actuation control device such as a hydraulic actuator, the actual actuation is determined based on the relationship between the actual actuation amount detected by the actual actuation amount detection means and the actuation target value set by the target value setting means. operation ratio calculation means for calculating the operation ratio of the amount; and a final control unit for increasing or decreasing the final control amount supplied from the feedback control means to the working substance supply control means according to the operation ratio calculated by the operation ratio calculation means. The present invention is characterized in that a control amount correction means is provided.

(Function) The configuration of the operation control device for a hydraulic actuator, etc. of the present invention described above is configured using an actuator operating substance such as oil whose operating energy transmission characteristics change depending on changes in physical characteristic conditions such as temperature. a predetermined actuator;
target value setting means for setting an operation target value of the predetermined actuator; actuation substance supply control means for supplying an amount of actuation substance to the actuator according to the operation target value set by the target value setting means; Actual operation amount detection means for detecting an actual operation amount of the actuator that is actually operated according to the amount of the actuation substance supplied by the actuation substance supply control means; and an actual operation amount detected by the actual operation amount detection means. In an actuation control device such as a hydraulic actuator, the actuation control device for a hydraulic actuator or the like is provided with feedback control means for feedback controlling the actuation substance supply control means according to a deviation from the actuation target value set by the target value setting means. an operation ratio calculation means for calculating an operation ratio of the actual operation amount to the operation target value from the relationship between the actual operation amount detected by the means and the operation target value set by the target value setting means; and the operation ratio calculation means A final control amount correction means is provided for increasing or decreasing the final control amount supplied from the feedback control means to the working substance supply control means in accordance with the operation ratio calculated by the operation ratio calculation means. The final control amount itself for the working substance supply control means is corrected to increase or decrease from the normal value in accordance with the determined operating ratio, and is automatically changed to an appropriate value corresponding to the change in the characteristics of the working substance.

That is, in the actuation control device of the present invention, first, the rate at which the setting amount of the actuation target value set on the operation control unit side and the final control amount change is basically linear, so first, the setting amount of the actuation target value is changed. The actual rate of change (actuation ratio) of the actuator-side actuation amount relative to that is first calculated, and the final control amount in the next cycle is increased or decreased based on the calculated value, so the set actuation target is It becomes possible to increase the degree of convergence to the value.

(Effects of the Invention) Therefore, according to the operation control device for a hydraulic actuator, etc. of the present invention, even if a factor that changes the operating characteristics of the actuator actuating substance, such as a change in oil temperature, occurs, the change in the operating characteristics due to the factor can be prevented. It is possible to take in the control factor in the previous cycle or previous control, increase or decrease the final control amount for the working substance supply control means, and then reflect it in the next control, so the operation target value that has been set for operation can be reflected in the next control. The ratio of the final control amount to the final control amount can always be adjusted to match changes in the operating characteristics, and the responsiveness and control accuracy of feedback control are greatly improved.

(Embodiment) FIGS. 1 to 4 show an operation control device for a hydraulic actuator or the like according to an embodiment of the present invention.

First of all, FIG. 1 shows the overall configuration of the control system of the device according to the embodiment, and the reference numeral 1 in the figure indicates a hydraulic actuator such as a hoisting cylinder of a hydraulic crane, and the hydraulic actuator l is Hydraulic oil is supplied from a first oil pump (hydraulic pump) 5 via a three-position directional switching valve 2 . Note that the reference numeral T1 indicates the first oil tank.

The three-position directional switching valve 2 is connected to a spool 4 via a piston 9 of a system control control cylinder (remote control cylinder) 4, which is a hydraulic actuator.
A first position 2a that supplies operation A1] in the forward direction by the operation of C (described later), a second position 2b that supplies hydraulic oil in the reverse direction, and a third position in a neutral state where the supply of hydraulic oil is stopped. 2c, the spool can be controlled to be switched arbitrarily between three spool positions, for example, the first position 2a in the forward direction.
When the switch is made, the operating rod 1c of the hydraulic actuator 1 operates in the extending direction shown by the arrow (A). Furthermore, when the actuating rod Ic is switched to the second position 2b in the opposite direction, the actuating rod Ic moves in the direction of the arrow (b) opposite to that in the forward direction.
It operates in the contraction direction shown by .

Furthermore, when switched to the third position 2c in the neutral state, the neutral state (stopped state) is maintained as it is. Note that reference numeral 12 is an operating lever for manual operation.

By the way, the control cylinder 4 has a first working chamber 4 defined in the front and back with the position of the piston 9 as a boundary.
a and a second working chamber 4b, and the first and second working chambers 4a and 4b are provided with ON-OFF driven first and second electromagnetic on-off valves 7A and 7B, respectively. Oil is supplied from the second oil pump 6 through the second or first working chamber 4b,
4a corresponds to the second oil pump T.
, to be returned to the side. In this embodiment, the first and second electromagnetic on-off valves 7A and 7B are configured to operate on or off at will, respectively. First, the first and second electromagnetic valves shown in FIG. When the on-off valves 7A and 7B are both in the "OFT" state, the respective operating chambers 4a and 4 are
b to the second oil tank T2 to maintain the control cylinder 4 in a neutral state,
On the other hand, in the ON state, the following different operations occur depending on which of the electromagnetic on-off valves 7A or 7B is ON.

That is, for example, the first and second electromagnetic on-off valves 7
A, 7B are both OFF as shown in FIG. 1, for example.
Feedback control is started from the neutral state of the control cylinder 4 in the state shown in FIG. 2nd from position 7A+, 7B+
When the spool position is switched to 7Δ2.782, the pump pressure from the oil pump 6 acts in the first working chamber 4a of the control cylinder 4 via the pressure valve 71 on the first electromagnetic shut-off valve 7A side. On the other hand, the second working chamber 4b of the control cylinder 4 also has a second
Pump pressure from the oil pump 6 acts through the exhaust valve 72 of the electromagnetic on-off valve 7B, and the control cylinder 4 is in a state where pilot pressure is established on both the first working chamber 4a side and 4b side. It is maintained in an inactive state similar to a neutral state.

Next, if, for example, it is desired to extend the actuating rod Ic of the hydraulic actuator l by a predetermined amount in the direction of the arrow (A) in FIG. Set target value i. Then, the operation control unit IO, which will be described later, supplies an OFF operation amount signal EB corresponding to the operation target value 1 to the electromagnetic solenoid terminal of the second electromagnetic on-off valve 7B from one of the output terminals of the two sets of I10 boats. Then, the electromagnetic on-off valve 7B of the box 2 is operated for a predetermined period t shown in the second cycle (b) of FIG. 4(b).
FF to communicate the second working chamber 4b of the control cylinder 4 with the second train side oil tank 1''. As a result, the spool 4c of the control cylinder 4 operates to the right by the operating stroke amount Ps corresponding to the operating target value i, thereby switching the foot pressure position direction switching valve 2 to the first position 2a in the forward direction. At the same time, oil corresponding to the actuation stroke amount Ps is supplied to the supply i+b chamber la side of the hydraulic actuator 1 to extend the actuation rod lc over the target actuation amount. Therefore, the second electromagnetic on-off valve 7B is turned OFF.
The time t1 ultimately corresponds to the operation target value i of the pressure actuator l, and in principle, the time t1 corresponds to the operation target value i of the pressure actuator l.
1 determines the operating stroke amount Ps of the control cylinder 4 for hydraulic actuator drive control.

However, as mentioned earlier in the prior art section, since the control cylinder 4 simply operates the directional control valve, its cylinder capacity is naturally small, and the diameter of the oil passage is also small. small. Therefore, the amount of oil that circulates is small, which tends to cause an increase or decrease in oil temperature and a change in flow resistance. Therefore, the viscosity of the oil (actuator operating substance) supplied to and discharged from the working chamber 4a or 4b changes greatly due to the oil temperature change,
As a result, the amount of oil actually supplied to and discharged from the working chamber 4a or 4b per unit time also varies considerably. Therefore, even if the OF'F time t of the second electromagnetic on-off valve 7B is constant, if the oil temperature differs as described above, the operating stroke amount Ps of the spool 4c of the control cylinder 4 itself will be It's going to be different.

Therefore, as a countermeasure against this problem, the following measures are taken in this embodiment.

In addition, in the case of the configuration of this embodiment, the operation target value i set by the operation section II is originally a value (heave speed) for actuating the hydraulic actuator 1, which is the final control target object.
It is.

However, the hydraulic actuator 1 has a large cylinder capacity and a large oil passage pipe diameter, and the 3-position directional control valve 2
A large amount of oil is distributed through the Therefore, even if there is a change in oil viscosity due to a change in oil temperature, this has a relatively small effect on the amount of cylinder operation. Therefore, the operating amount of the hydraulic actuator l whose drive is indirectly controlled by the control cylinder 4 itself is the operating stroke f of the spool 4c of the control cylinder 4.
It can be seen as corresponding to fi Ps.

As is clear from the above, in the case of the configuration of this embodiment shown in FIG. Since there is a linear relationship between zl and l, in short, in order to operate the hydraulic actuator l according to the operation target value set in the operating section 11, it is necessary to It is sufficient to accurately control the actuation stroke amount Ps of the control cylinder 4 to an actuation stroke amount that accurately corresponds to the actuation target value i set by the operation section 11, and the direct It can be seen that the control object is the control nolinda 4 described above. Therefore, in order to make the explanation of the control operation easier to understand, in order to make the explanation easier to understand, the hydraulic actuator and the hydraulic circuit on the eta l side will be ignored, and the actuation target value l set by the operation unit 11 will be set to the control shilling. The explanation will be made by replacing the target operation stroke amount of the spool 4C in No. 4 with the target operating stroke amount.

First, as mentioned earlier, the symbol IO is a variable for arbitrarily changing the ON/OFF time of the first and second electromagnetic on-off valves 7A7B, which are means for controlling the supply of hydraulic oil to the control nolinder 4. This is an operation control unit as a feedback control means that outputs final control amount signals EA and EB for control.

The operation control unit]0 is, for example, 8 bits (or 12 bits).
It is constituted by a micro combicoater of the order of magnitude (Pitt), including a calculation section and a memory section, and the operation target value of the control cylinder 4, which is set by the operation section (target value setting means) If, is stored in the section 110. (equal to the operating target value of the hydraulic accelerator 1) i and the control amount measuring section 8
Actual operating stroke amount P of the spool 4c in the control cylinder 4 that has been moved in accordance with the operating target value i set in advance by the operating section 11, as measured by
A feedback amount d (a measured value of the actual operating stroke amount Ps of the spool 4c expressed as a control amount) corresponding to s is inputted.

Further, reference numeral 3 is an operating transformer, and the actual operating stroke tft of the spool 4c of the control cylinder 4 is
P s is detected and the detected actual operating stroke m P
s is input to the control amount measuring section 8. Controlled amount measuring section 8
converts the actual operating stroke amount Ps of the spool 4c into a control amount and outputs it.

Then, the operation control unit 10 performs an increase/decrease correction operation of the final controls 11EA and EB as shown in the flowchart of FIG. 2, for example, based on the input values i and d.

That is, first, in step S1, the operation target value 1 set by the operation section 11 and the feedback amount d measured by the control amount measuring section 8 are read, and at the same time the current cycle (as shown in FIG. 4 (b)) is read. The feedback Mid in the first period) is temporarily stored in a memory (RAM) (this stored value is used in the calculation of the next step).

Next, the process proceeds to step S2, where the feedback amount d is an actual value actually measured from the current operation target value i.
By subtracting , the deviation Δd between the actual operating stroke amount d actually realized on the control cylinder 4 side and the operating target value i originally set on the operation unit 11 is calculated by subtracting Δd=i−d
Calculate. Thereafter, the process further advances to step S3.

In step S3, a correction control amount ΔE corresponding to the deviation Δd calculated in step S is calculated.

This is a so-called feedback correction amount, and it goes without saying that the feedback correction amount is determined by the temperature T of the hydraulic fluid.
When H is at the standard temperature T Hs (T l-1s = 60°C) shown by the characteristics shown in Fig. 3 (a) to (c) and there is no disturbance, the actual spool operating stroke amount Ps is calculated from the above operating target. This is the optimum increase/decrease correction value (integral amount) for convergence (coincidence) with the value i (see FIGS. 3 a-c).

Next, in step S4, the above-mentioned step S in the previous cycle is performed.
Based on the memory operation of the feedback ID in step 1 (using the previous control result), the set operation amount (
Actual feedback l'back amount (operation target value)
Actuation ratio (actuation ratio) of measured actuation stroke amount) d =
Calculate i/d. Then, in the next step S5, the correction control amount ΔE under the standard temperature of 60° C. calculated in the step S3 in the current cycle is multiplied by the operating ratio K calculated in the step s4. E is increased/decreased (8E-K) to the corrected control amount to obtain the final control amount EI3.

Next, it is determined whether or not the corrected final control amount exceeds a predetermined upper safety limit value (for example, the second limit value of the hoisting speed) from the perspective of the function of the hydraulic actuator 1, and then If YES exceeds the upper limit value Vs, the final control ff1E to be output to the electromagnetic on-off valves 7A and 7B
B is fixed by applying a guard to the same upper limit value EB (MAX) within the safe limit range.'' At this point, the process proceeds to final step S8, where the guard value is outputted as the final control output amount EB, and the electromagnetic on-off valve 7B is control the OFF time.

On the other hand, in the case of NO, where the safety limit upper limit value Vs is not exceeded, the process directly proceeds to the final step S8 and the above step S
The multiplication correction value (ΔE-K) in step 5 is used as the final control amount EB to control the OFF time of the electromagnetic on-off valve 7B (see FIGS. 3(g) to 3(i)).

As a result, according to the configuration of this embodiment, for example, FIG.
) to (f), as shown in Figure 3 (a) to (f),
c) Based on the calculation of the controlled variable under the standard temperature condition, the conventional low-temperature characteristics that require convergence to the target value i over a long period of time (multiple periods) using a small integral amount are Figure 3 (
As shown in the characteristics of g) to (i), when the predetermined control (driving the control cylinder 4) is performed and the difference Δd of the feedback H1d with respect to the operation target value i is large,
Based on the difference Δd, the operating ratio K is calculated according to the oil temperature change, and from the next control cycle, the corrected control amount ΔE itself at the standard temperature, which is determined corresponding to the above Δd, becomes larger according to the operating ratio K. Since it is controlled to increase (in the case shown in the figure), it quickly converges to the original operating target value i after that period.

The relationship between them will be described more specifically in relation to the operations of the first and second electromagnetic on-off valves 7A and 7B, which are the hydraulic oil supply control means, as follows.

Zunaichi, first of all, the neutral state of the control cylinder 4 (electromagnetic on-off valve 7A 7B
Both input control amount signals EA and EB are “H” level ON
When only the second electromagnetic on-off valve 7B is turned OFF within time t1 corresponding to the operation target value 1 from the neutral state (period shown in Fig. 4 (a)), the amount corresponding to the OFF time t1 The oil is in the first working chamber 4 of the control cylinder 4.
a, and the spool 4C moves in the predetermined operating stroke amount Ps+rightward according to the amount of supplied oil. If the oil temperature T Hs at that time is a standard temperature of 60° C. and the amount of movement of the operating stroke amount Psl of the control cylinder 4 is relatively small relative to the operating target value i, the operating stroke amount Ps+ is determined by the disturbance. Unless otherwise specified, the above operation section 1
In principle, this corresponds to the operation target value i set in 1. However, if the actuation stroke amount PsI of the control cylinder 4 is relatively large with respect to the actuation target value 1, the deviation Δd between the actuation target value i at that time and the feedback amount d
Based on the above, the corrected control amount ΔE for the OFF time t is determined, and the next period (
c) further extends the OFF time. If it still does not converge to the target value i, do the same in the control cycles (d), (e), (e), (g), (ch), and (su) that continue until convergence. The actual supply oil amount is corrected (4th
t3-18 in the figure). As a result, control cylinder 4
Feedback control is performed so that the actual operating stroke length PS becomes equal to the operating target value i. As a result, the actual operating stroke Ps of the control cylinder 4 eventually converges to the operating target value i (see FIG. 3(a)).

However, for example, when the oil temperature THs of the hydraulic oil is lower than the standard temperature of 60° C., the viscosity of the oil becomes higher than its characteristics at the standard temperature, resulting in poor flowability. Therefore, as shown by the solid line in FIG. 4(b) above, the drain side valve opening time (Or' F time) of the electromagnetic on-off valve 7B in each cycle is 1. ．． 12...tn as shown in Fig. 3 (a) to (c) above.
If it is determined and controlled based on the characteristics at the standard temperature shown in , the actual amount of oil supplied for each cycle will end up being smaller than the amount of oil that is originally required. As a result, Figure 3 (
As shown in d) to (f), it takes a long time to converge to the operation target value i, and the control responsiveness deteriorates.

However, as described above, in the configuration of the embodiment of the present invention, first, in the calculation program at the initial stage of the feedback control (for example, the first time (b)), the actual operating stroke amount Ps for the above-mentioned operating target value i is expressed by the feedback control fid. Above, the ratio of the commanded actuation amount l to the actual actuation stroke amount d, that is, the actuation ratio i/d=K, is calculated, and from the next feedback control cycle (c), the final control ff1EB, in other words, is performed according to the calculated value K. Then, the second electromagnetic on-off valve has an OFF time of 7 days t3. t3...tn in Figure 4(b)
As shown by the imaginary line, control is performed so that the actual amount of oil supplied to the control cylinder 4 matches the original required amount of oil by increasing the amount of oil for a predetermined period of time (see FIGS. 3(g) to 3(i)). As a result, even when the temperature THs of the hydraulic oil is lower than the standard temperature of 60°C, the operation of the control cylinder (hydraulic actuator) 4 can be controlled stably in the same way as when the temperature is at the road standard temperature. become.

In the above embodiment, the control cylinder 4 is used as a driving means for the 3-position directional switching valve 2 during remote control, and the 3-position directional switching valve 2 is indirectly driven. It goes without saying that the position-direction switching valve 2 may be driven, and in that case, it goes without saying that the three-position-direction switching valve 2 is selected as the object to be directly controlled in setting the operating target value.

In addition, in the previous embodiment, the hydraulic actuator 1 in FIG.
In the case of the 3-position directional control valve 2, the cylinder capacity is large and the amount of oil flowing is also large, so the change in stroke amount of the spool or cylinder capacity due to viscosity changes as in the case of the control cylinder 4 is relatively small. I assumed that it could be ignored. However, it goes without saying that the present invention can also be applied to cases where oil temperature changes are rapid or highly accurate operation stroke control is required, and has sufficient merits.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing the configuration of an operation control device for a hydraulic actuator according to an embodiment of the present invention, FIG. 2 is a flowchart showing the control operation of the device according to the embodiment, and FIGS. 3 and 4 are , is the same time chart. 1...Hydraulic actuator 2...3 Position directional switching valve 4...Control cylinder 5 ・ ・ 6 ・ ・ 7A ・ 7B ・ 8 ・ ・ 9 ・ ・ l O・ l 1 ・ ・First oil pump, second oil pump, first electromagnetic on-off valve, second electromagnetic on-off valve, control amount measuring section, control cylinder spool, operation control unit, operation section 24~

Claims (1)

[Claims] 1. A predetermined actuator configured using an actuator operating substance such as oil whose operating energy transfer characteristics change depending on changes in physical characteristic conditions such as temperature, and target value setting for setting an operating target value of the predetermined actuator. means, actuating substance supply control means for supplying the actuator with an amount of actuating substance according to the actuation target value set by the target value setting means; an actual operating amount detection means for detecting the actual operating amount of the actuator that actually operates according to the actual operating amount, and a link between the actual operating amount detected by the actual operating amount detecting means and the operating target value set by the target value setting means. In an operation control device such as a hydraulic actuator, comprising feedback control means for feedback controlling the working substance supply control means according to a deviation, the actual operation amount detected by the actual operation amount detection means and the target value setting means. operation ratio calculation means for calculating the operation ratio of the actual operation amount to the operation target value from the relationship with the operation target value set by the operation ratio calculation means; and the feedback control means according to the operation ratio calculated by the operation ratio calculation means. An operation control device for a hydraulic actuator or the like, characterized in that it is provided with final control amount correction means for increasing or decreasing the final control amount supplied to the working substance supply control means.