JP2001248566A - Pump rotation speed control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a speed command Rc to correspond to a flow rate Q accurately. SOLUTION: This pump rotation speed control system driving a liquid pump 4 by a servo motor 3 is provided with a pressure detection means 4a detecting a discharge pressure of the liquid pump 4, a compensation amount calculating means 31 calculating a compensation amount f (Pf) related to a discharge amount Q of the liquid pump 4 based on the results Pf of the detection, and a synthesis means 33 receiving a speed command Pc for the servo motor 3 to correct with the compensation amount f (Pf). Consequently, it is possible to allow accurate correspondence between the speed command Rc and the flow rate Q by taking a leakage amount E in accordance with a pump discharge pressure into account to compensate rotation speeds of the motor and the pump and perform the compensation for the speed command Rc (Rm) in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump rotational speed control system in a hybrid system in which a hydraulic system such as a hydraulic system is combined with an electric motor having a variable rotational speed, and more particularly, to the rotation of an electric motor for driving a liquid pump. The present invention relates to an improvement of a control system for variably controlling a speed.

[0002]

2. Description of the Related Art In a hydraulic system (hydraulic system) for driving an operating unit by feeding oil (liquid) to a hydraulic actuator (operating unit) such as a hydraulic cylinder or the like, a constant displacement hydraulic system is operated by an electric motor having a constant rotation speed. Drive the pump (liquid pump) and control the operating state by returning the required amount of pressure oil from the pump to the actuator by the required flow rate to the tank by means of a relief valve, direction control valve, etc. Basically, there are systems using hydraulic servo valves and variable displacement hydraulic pumps.However, recently, in addition to the advantages of low energy consumption and low noise, In addition to the advantages of easy control such as speed control and pressure control that follow the speed and stability of the control state, the hybrid Ddoshisutemu have been increasing.

A system shown in a block diagram in FIGS. 8A and 8B is a typical example of such a system, in which the main controller 1 issues a control command to some drive systems while controlling the order corresponding to the application. A pump rotation speed control system that drives the liquid pump 4 with a servomotor 3 is employed as one of the drive systems. An operating unit 5 is connected to the discharge side of the liquid pump 4 via a pipe such as an appropriate rubber hose or a metal pipe so as to be hydraulically driven, and a drive current is supplied to the servo motor 3 so that the servo motor 3 can be supplied with a drive current. The motor control electronic circuit 2 is connected, and the motor control electronic circuit 2 is connected to the main controller 1 so as to be able to send and receive signals, and receives a speed command Rc generated by the main controller 1 based on the speed command Rc. Speed control is performed.

Therefore, the motor control electronic circuit 2 includes:
A motor driver 29 having a power transistor or the like to generate a drive current for the servo motor 3, and a three-phase pulse signal, for example, for generating a three-phase pulse signal for controlling on / off of the power transistor in association with each phase of the servo motor 3. And a motor controller 20 for sending the motor controller 20 to the motor driver 29. The rotation speed control of the servo motor 3 by the motor controller 20 is a general one in which the current control by the current control means 24 is a minor loop, and the speed control by the speed control means 21 is a feedback loop outside the multiplex feedback control. is there.

That is, the speed control means 21 generates a current command Ic which brings the rotational speed Rf of the servomotor 3 close to and matches the speed command Rc, and the current control means 24 applies the drive of the servomotor 3 to the current command Ic. A control signal for matching the current If is generated and sent to the signal conversion means 25, and the signal conversion means 25 performs appropriate processing such as pulse width modulation to generate a three-phase pulse signal to the motor driver 29. It has become. The drive current If supplied from the motor driver 29 to the servomotor 3 accordingly.
Is detected by an appropriate current detecting means and is fed back to the current control means 24, and a rotation speed detecting unit 3a is provided on the servo motor 3 or its output shaft, whereby the rotation speed Rf of the servo motor 3 is detected. The speed is returned to the speed control means 21. The speed control means 21 is basically a speed error calculating unit 22 for calculating the difference ΔR by subtracting the speed Rf from the speed command Rc. Arithmetic unit 23
Is also provided, so that appropriate processing such as amplification and integration is performed on the difference ΔR.

In such a system, the main controller 1 only needs to issue a speed command Rc when it is desired to control the operating state of the operating section 5. Motor 3
Is performed such that the rotation speeds Rf of the liquid pumps 4 coincide with each other, and stable driving of the liquid pump 4 is performed with good energy efficiency.

[0007]

However, the amount of internal leakage E in a liquid pump whose rotational speed is controlled to vary the number of rotations and the amount of high-pressure liquid leakage from equipment used in a hydraulic circuit or the like are as follows. It changes greatly depending on the discharge pressure P of the liquid pump. Specifically, (see FIG. 8C), the higher the pressure P, the larger the leakage amount E and the like, and the speed command R
The difference between c and the discharge amount Q also increases. For this reason, for example, when the pressure P increases in response to an increase in the reaction force in the operating unit 5 when the operating member of the operating unit 5 is driven at a low speed, the discharge amount Q is constant even if the speed command Rc is constant. In addition to the decrease (see the graph at the bottom of FIG. 8C), the relative rate is large, so that the traveling speed of the operating member may undesirably decrease or stop.

[0008] The amount of leakage E of the liquid pump also changes depending on its rotational speed. Specifically, (see FIG. 8C), as described above, the higher the pressure P and the higher the pump rotation speed, that is, the larger the discharge amount Q, the larger the leakage amount E, and the difference between the speed command Rc and the discharge amount Q is increased. The deviation also increases. For this reason, when various operating states are assumed by an application or the like, a change in the discharge amount Q due to a change in the pump rotation speed cannot be ignored. Further, the leakage amount E of the liquid pump and the leakage amount from each device on the hydraulic circuit vary depending on the liquid temperature such as the oil temperature.

Therefore, it is a technical problem how to remove and suppress the above-mentioned undesired fluctuation factors while securing the advantage of the hybrid system for automatically controlling the pump rotation speed. In other words, it is required to improve so that the liquid supply amount to the operation unit accurately corresponds to the speed command. At this time, however, the control characteristics are changed so as to affect the stability of the control state. It is also important to avoid such changes that complicate the order control means whose contents change for each application, and to deal with them simply. The present invention
It was made to solve such a problem,
It is an object to simply realize a pump rotation speed control system in which a speed command and a flow rate accurately correspond.

[0010]

Means for Solving the Problems Structures and operational effects of the first to third solving means invented to solve such problems will be described below.

[First Solution] A pump rotation speed control system according to the first solution is capable of driving a liquid pump such as a hydraulic pump and the like, as described in claim 1 of the present application. And a motor control electronic circuit that controls the servomotor so that the rotation speed of the servomotor follows an externally received or internally generated speed command. In the rotation speed control system, pressure detection means for detecting a discharge pressure of the liquid pump is provided for a discharge side of the liquid pump or a flow path ahead thereof, and a discharge amount of the liquid pump is determined based on a result of the detection. Compensation amount calculating means for calculating a compensation amount for the servo motor, and synthesizing means for receiving a speed command to the servomotor and correcting the value with the compensation amount. Is provided in the motor control electronics, is that.

Here, the above-mentioned "speed command" indicates a target rotation speed of the liquid pump. However, like the command for specifying the target discharge amount of the liquid pump, a certain clear relationship such as a proportional relationship or a linear relationship is provided. Directives having a corresponding relationship are also equivalent.
The “compensation amount relating to the discharge amount of the liquid pump” basically takes into account the leakage amount of the liquid pump, and although it depends on the application, etc., in the hydraulic circuit such as a hydraulic circuit in the middle of the flow path. The amount of leakage and the amount of leakage in the final stage operating section are not taken into account.

In the pump rotation speed control system according to the first solution, the rotation speed of the servomotor is controlled in accordance with the speed command, and a liquid having a flow rate corresponding to the rotation speed is discharged from the liquid pump. At this time, the discharge pressure of the liquid pump is detected by the pressure detecting means, and the compensation amount for compensating the leakage amount with respect to the discharge amount of the liquid pump is calculated by the compensation amount calculating means based on the detection result, and the combined amount is calculated. By means, the value of the speed command is corrected by the compensation amount. Then, the speed of the motor rotation is controlled by the corrected command value, and the pump discharge amount also becomes a flow rate corresponding thereto.

Thus, even if there is a leak in the liquid pump or the like, and even if the amount of the leak greatly changes according to the pressure, the value of the speed command is appropriately corrected, and the pump discharge amount compensates for the leak. Therefore, the liquid supply amount to the operating portion accurately follows the speed command before correction, apart from the difference in the unit between the speed and the flow rate. As described above, the rotational speeds of the motor and the pump are compensated for in consideration of the leakage amount corresponding to the pump discharge pressure, so that the speed control of the operating member is accurate and stable. In particular, the relative accuracy at low speed is greatly improved.

Further, since the processing for this is performed on the speed command after it is generated and before it is used for controlling the servomotor, the processing for generating the command is not complicated or complicated. There is no need to change the essential and permanent control characteristics of the servomotor. Therefore, according to the present invention, it is possible to easily realize a pump rotational speed control system in which the speed command and the flow rate accurately correspond.

[Second Solution] The pump rotation speed control system according to the second solution is the pump rotation speed control system according to the first solution as described in claim 2 of the present application. The compensation amount calculation means calculates the compensation amount by using the speed command together with the detection result of the pressure detection means when calculating the compensation amount.

In the pump rotational speed control system according to the second solution, not only the pressure but also the rotational speed is taken into account when compensating for the leakage amount. The rotational speeds of the motor and the pump are appropriately compensated in a wide range up to this, so that the speed control of the operating member is accurate and stable. Therefore, according to the present invention, it is possible to easily realize a pump rotation speed control system in which the speed command and the flow rate correspond more accurately.

[Third Solution] A pump rotation speed control system according to a third solution of the present invention is the pump rotation speed control system according to the first and second solutions described above. It is provided with a temperature detection means provided for the liquid pump or the flow path of the discharge destination thereof and measuring the temperature thereof, wherein the compensation amount calculation means, when calculating the compensation amount, the pressure detection means The calculation is performed based on the detection result and the detection result of the temperature detection unit, or based on the detection result of the pressure detection unit, the detection result of the temperature detection unit, and the speed command.

Here, the above-mentioned "provided to the pump" means not only a state directly provided on the pump but also the pump and related members made of metal or the like having excellent heat conductivity. In such a case, a state provided in a member near the pump that can be regarded as being the same as the pump thermally corresponds. For example, a metal flange or a metal pipe connected to a pump discharge port or a suction port is applicable, but a rubber pipe having poor heat conductivity is excluded. However, even if a rubber pipe is connected to the discharge side of the pump, it may correspond to “provided for the discharge destination flow path of the pump”.

In the pump rotation speed control system according to the third solution, not only the pressure but also the liquid temperature such as the oil temperature is taken into account when compensating the amount of leakage. The rotation speeds of the motor and the pump are appropriately compensated over a wide range from pressure to high pressure, and the speed control of the operating member is accurate and stable. Therefore,
According to the present invention, it is possible to easily realize a pump rotation speed control system in which the speed command and the flow rate correspond more accurately.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments for implementing the pump rotational speed control system of the present invention achieved by such a solution will be described.

According to a first embodiment of the present invention, as described in claim 4 of the present application, a pump rotational speed control system according to the above-mentioned solving means, wherein the contents of calculation of the compensation amount calculating means are discretely provided. Alternatively, it is provided with a compensation content variable means that can be changed continuously. This allows easy and quick adaptation to various applications.

A second embodiment of the present invention is a pump rotation speed control system according to the above-described solving means and the embodiment, as described in claim 5 at the beginning of the application, wherein the motor control electronic circuit includes: Force control means for performing control on the servomotor such that a feedback value of a detection result of the pressure detection means follows a force command received from outside or generated internally, and force control by the force control means; Switching means for selectively performing speed control based on a speed command. Alternatively, a force detecting means provided in a hydraulic circuit or an operating portion of a discharge destination of the liquid pump separately from the pressure detecting means to detect a force such as a pressure or an operating force thereof, and the detection result is transmitted to the motor controlling electronic device. Means for feeding back to the circuit, wherein the motor control electronic circuit includes a force control for controlling the servomotor so that the feedback value follows a force command received from outside or generated internally. Means and switching means for selectively performing force control by the force control means and speed control based on the speed command. This makes it possible to achieve both accurate speed control and stable and flexible force control.

A third embodiment of the present invention is a pump rotation speed control system according to the above-mentioned solving means and the embodiment, as described in claim 6 at the beginning of the application, wherein the servo motor is replaced with a rotation speed control system. An electric motor without feedback is provided, and its drive current is supplied by an inverter, and the inverter changes the frequency of the drive current according to the speed command.
As a result, the application of the present invention extends to an inexpensive system using a normal electric motor.

A fourth embodiment of the present invention is a pump rotation speed control system according to the above-mentioned solving means and the embodiment, as described in claim 7 at the beginning of the application, wherein the servo motor is controlled based on the speed command. When the control is performed by detecting the rotation speed and further feeding back, the control result equivalent to increasing or decreasing the speed command itself can be obtained by reducing or increasing the feedback amount of the rotation speed. And
The synthesizing means adjusts the feedback amount of the rotation speed when compensating the speed command.

Specific embodiments for carrying out the pump rotation speed control system of the present invention achieved by the above-described means and embodiments will be described with reference to the following first to seventh embodiments. The first embodiment shown in FIG. 1 embodies the above-described first solution (first claim 1), and the second embodiment of FIG. 2 additionally includes the second solution ( Initially, claim 2) is also realized, and FIG.
The third embodiment of the present invention further embodies the third solution means (claim 3 initially). Further, the fourth embodiment of FIG. 4 embodies the above-described first embodiment (initial claim 4), and the fifth embodiment of FIG. 5 implements the above-described second embodiment (initial claim 4). 6) embodies the above-described third embodiment (initially claim 6), and the seventh embodiment of FIG. 7 embodies the above-described third embodiment. 4th
It embodies the embodiment (initially claim 7).

In the drawings, for simplicity and the like, the housing panel, bases, frames, fasteners such as bolts and couplings such as hinges are omitted from the drawings, and are necessary for the description of the invention. The objects and related items are shown mainly by symbols and blocks. In addition, regarding the operation characteristic graph, the speed command and the discharge amount are converted at a predetermined ratio based on a difference in units and the like, and the graphs overlap when the two correspond ideally. In the drawings, the same components as those in the related art are denoted by the same reference numerals, and the description thereof will not be repeated, and the following description will focus on the differences from the related art.

[0028]

First Embodiment A first embodiment of a pump rotation speed control system according to the present invention will be described with reference to the drawings. FIG. 1A is an overall block diagram, and FIG.
(B) is a block diagram of the motor controller, and FIG.
FIG. 3 is a block diagram of an adjusting unit. This pump rotation speed control system is different from the above-described conventional one in that a pressure detecting means 4a for detecting the pressure Pf is provided.
The difference lies in that an adjusting means 30 is provided in the motor controller 20 of the motor control electronic circuit 2.

As the pressure detecting means 4a, a pressure gauge with a piezoelectric conversion circuit or the like is employed. In order to detect the discharge pressure of the liquid pump 4, it is connected to a discharge port of the liquid pump 4 or a pipe ahead thereof. Is done. The detected pressure Pf is fed back to the motor controller 20 via an appropriate signal cable or the like, and is used by the adjusting means 30 there.

The adjusting means 30 is provided for the line for inputting the speed command Rc, and performs an appropriate adjusting process before passing the speed command Rc to the speed control means 21 to obtain a speed command Rm. Instead of the speed control means 21. Further, in order to compensate for the internal leakage amount E of the liquid pump 4 which fluctuates according to the pressure, the adjusting means 3 performs the adjusting process by an appropriate amount based on the pressure Pf.
0 is provided with a correction amount calculating unit 31 and a synthesizing unit 33.

The correction amount calculating means 31 is a function calculating means of one variable x, and comprises an appropriate adding circuit, multiplying circuit and the like.
When the viscous flow is dominant, the function f (x) can be satisfied by the linear expression [a · x + b], but in many cases the quadratic expression [a · x · b] is sufficient.
x + b.x + c], and an equation that also takes into account terms of intermediate orders may be adopted. Note that a,
b and c are coefficients of predetermined values, and are determined based on an experimental result or the like in which the leakage amount E which is an undesired decrease factor of the discharge amount Q is measured while changing the pressure Pf. If the amount of leakage in the operating section 5 and the like in addition to the amount of leakage E can be measured, it is desirable to reflect the amount in the expression taking that into account. The correction amount calculating means 31 calculates the compensation amount f (Pf) related to the discharge amount Q of the liquid pump 4 by applying the function f (x) to the pressure Pf.

The synthesizing means 33 receives the speed command Rc for the servomotor 4 from the main controller 1 and receives the compensation amount (Pf) from the correction amount calculating means 31.
In order to correct the value of the speed command Rc with the compensation amount (Pf), the speed command Rc is constituted by, for example, an adder circuit which receives the input, and outputs the added value as the speed command Rm.

The usage and operation of the pump rotational speed control system according to the first embodiment will be described with reference to the drawings. FIG. 1D is an operation characteristic graph in which the horizontal axis indicates the discharge pressure Pf of the pump 4 and the vertical axis indicates the discharge amount Q and the speed commands Rc and Rm. Here, the speed command R
A description will be given of a low speed range in which the influence of the difference between c and the discharge amount Q is particularly large.

In this system, the advantages of the hybridization are maintained as before. That is, when it is desired to control the operation state of the operation unit 5, the main controller 1 only needs to issue the speed command Rc, and the speed control of the servo motor 3 that follows the speed command Rc is performed by the motor control electronic circuit 2. Thus, stable driving of the liquid pump 4 is performed in a state of good energy efficiency and the like.

However, in this system, when the speed control by the motor control electronic circuit 2, more specifically, the speed control by the motor controller 20, the adjusting means 30
Operates on the speed command Rc, and the speed command Rc is replaced with the speed command Rm in front of the speed control means 21. Therefore, speed control is performed such that the rotation speed Rf of the servo motor 3 matches the speed command Rm. Will be

The speed command Rm (see the two-dot chain line graph in FIG. 1 (d)) is calculated based on the compensation amount f (P
f) With the addition, the value is larger than the speed command Rc by the amount of leakage E or by taking into account the amount of leakage of the operating unit 5 (see the solid line graph in FIG. 1D). Since the compensation amount f (Pf) and the leakage amount E cancel each other, the discharge amount Q of the liquid pump 4 corresponds to the speed command Rc regardless of the pressure Pf (FIG. 1D).
Solid line graph).

Thus, in this pump rotation speed control system, the motor controller is not changed without changing the control characteristics of the speed control means 21 and the current control means 24 and without changing the processing contents of the main controller 1. By simply adding an adjusting means 30 to 20, for example,
Even in the low-speed range and when the pressure Pf is high as well as when the pressure Pf is low, there is no difference between the speed command Rc and the discharge amount Q. Or smaller.

[0038]

Second Embodiment A specific configuration of a pump rotation speed control system according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2A is a block diagram of the adjusting unit 30. This pump rotation speed control system is different from that of the first embodiment in that the correction amount calculating means 31 in the adjusting means 30 calculates the function f (x, y) of the two variables x and y when calculating the compensation amount. That is, the calculation is started.

The function f (x, y) includes the liquid pump 4
Any appropriate one may be employed as long as it accurately reflects the amount of internal leakage E and the amount of leakage of the other operating parts 5 and the like, but in consideration of determination of coefficient values and simplification of calculation means, etc. In many cases, a function in which functions of one variable are multiplied is adopted. For example, [(a.x.x + b.x + c). ((D.y +
e)] is calculated. Note that a, b, c, d,
e is a coefficient of a predetermined value, and is determined based on an experimental result or the like in which the leak amount E and the like are measured while changing the pressure Pf and the speed command Rc or the discharge amount Q. Such a correction amount calculating means 31 adds a function f (x, y) to the pressure Pf and the speed command Rc.
To compensate for the discharge amount Q of the liquid pump 4
(Pf, Rc) is calculated.

The usage and operation of the pump rotation speed control system of the second embodiment will be described with reference to the drawings. FIG. 2B is an operation characteristic graph in which the horizontal axis indicates the discharge pressure Pf of the pump 4 and the vertical axis indicates the discharge amount Q and the speed commands Rc and Rm.

In this case as well, at the time of the speed control by the motor controller 20, the speed command Rc is corrected by the intervention of the adjusting means 30, and the speed control is performed such that the rotational speed Rf of the servo motor 3 matches the corrected speed command Rm. In this case, the speed command Rm (see the two-dot chain line graph in FIG. 2B) includes not only the pressure Pf but also the speed command Rc.
Is added to the compensation amount f (Pf, Rc), so that the compensation amount f (Pf, Rc) is obtained for any combination of the pressure Pf and the speed command Rc.
c) and the amount of leakage E cancel each other, and the discharge amount Q of the liquid pump 4 corresponds to the speed command Rc regardless of the pressure Pf and the speed command Rc (solid line in FIG. 2B). See graph).

As described above, in this pump rotation speed control system, the motor controller is not changed without changing the control characteristics of the speed control means 21 and the current control means 24, and without changing the processing contents of the main controller 1. By simply adding an adjusting means 30 to 20, for example,
In a wide range from a low speed range to a high speed range and from a low pressure to a high pressure, the difference between the speed command Rc and the discharge amount Q is eliminated or reduced.

[0043]

Third Embodiment A pump rotation speed control system according to a third embodiment whose overall block diagram is shown in FIG. 3 is different from that of the second embodiment described above in that a temperature detecting means for measuring the oil temperature is used. 4b and the function f (x, y, z) of the three variables x, y, z when calculating the compensation amount.
z) is calculated.

As the temperature detecting means 4b, a temperature detecting member such as a thermocouple provided with a reference signal generating circuit, a signal amplifying circuit, or the like, or another thermometer capable of outputting an appropriate signal is used.
The detected temperature Tf is returned to the motor controller 20 via an appropriate signal cable or the like, and is used by the adjusting means 30 there. In addition,
FIG. 3A shows a configuration in which the temperature detecting means 4b is attached to the liquid pump 4, and FIG. 3B shows a configuration in which the temperature detecting means 4b is connected to the piping from the liquid pump 4 to the operating section 5. In each case, the oil temperature near the discharge port is detected as much as possible. Alternatively, the oil temperature on the suction side is detected.

As the function f (x, y, z), any appropriate function may be used as long as it accurately reflects the internal leakage amount E of the liquid pump 4 and the leakage amount of the other operating parts 5 and the like. However, in consideration of the determination of the coefficient value and the simplification of the calculation means, a method of multiplying the functions of one variable in many cases is adopted. For example, [(a.x.x + b.x + c).
(D · y + e) · (h · y + i)] and the like are calculated. Note that a, b, c, d, e, h, and i in the formulas are coefficients of predetermined values, and are, for example, experimental results obtained by measuring the leak amount E while changing the pressure Pf, the speed command Rc, and the temperature Tf. Is determined based on The correction amount calculating means 31 calculates the pressure Pf,
By applying the function f (x, y, z) to the speed command Rc and the temperature Tf, the compensation amount f relating to the discharge amount Q of the liquid pump 4 is obtained.
(Pf, Rc, Tf) is calculated.

Also in this case, when the speed is controlled by the motor controller 20, the speed command Rc is corrected by the intervention of the adjusting means 30, and the speed control is performed such that the rotational speed Rf of the servo motor 3 matches the corrected speed command Rm. In this case, the compensation amount f (Pf, Rc, Tf) calculated based on not only the pressure Pf and the speed command Rc but also the temperature Tf is added to the speed command Rm.
Regarding any combination of the pressure Pf, the speed command Rc, and the temperature Tf, the compensation amount f (Pf, Rc, Tf)
And the leakage amount E and the like cancel each other, and the discharge amount Q of the liquid pump 4 is
Corresponds to the speed command Rc regardless of the pressure Pf, the speed command Rc, and the temperature Tf.

Thus, in this pump rotational speed control system, the motor controller is not changed without changing the control characteristics of the speed control means 21 and the current control means 24, and without changing the processing contents of the main controller 1. 20 simply by adding the adjusting means 30 to a wide range from a low speed range to a high speed range and from a low pressure to a high pressure. Even in a severe environment where fluctuates greatly, the difference between the speed command Rc and the discharge amount Q is eliminated or reduced. In addition, in the case of such a pump rotation speed control system, although the heat generation in the liquid pump 4 is generally small, depending on the use conditions, the temperature detection location is not limited to the discharge side of the liquid pump 4 and may be the suction side. Since substantially the same result can be obtained, the temperature detecting means 4b
This also has the effect of reducing the burden on mounting design and maintenance.

[0048]

Fourth Embodiment A pump rotation speed control system according to a fourth embodiment, in which a block diagram of the adjusting means 30 is shown in FIG. 4A, is different from that of the third embodiment described above in that a correction amount calculating means is used. 31 is increased to three, and the switching means 34 is interposed between the correction amount calculating means 31 and the synthesizing means 33.

The correction amount calculating means 31 calculates three types of compensation amounts f (Pf, Rc,
Tf) is calculated. The switching means 34 employs, for example, a three-input selector which receives them, selects one of them according to the selection signal S, and sends it to the compensation amount calculating means 33 in order to correct the speed command Rc. It is designed to be sent.

In this case, the selection signal A is given from the main controller 1 or by a switch input on the operation panel, etc., but depending on the setting, the effective calculation of the correction amount calculating means can be easily performed from outside. Since the content can be switched, and the adjustment content of the speed command Rc can be changed so as to be adapted to the characteristics of the operating section, it is possible to appropriately compensate various applications. The number of the correction amount calculating means 31 may be two,
Four or more may be used.

FIG. 4B shows a block diagram of the adjusting means 30. The pump rotation speed control system is a modified example or an extended example, in which the compensation amount varying means 35 is integrated with the compensation amount varying means 35. . In other words, the function f operated by the compensation amount calculating means 35 can change four coefficients a, b, c, and d in addition to the three variables x, y, and z as parameters. , C, and d are supplied to the compensation amount calculating means 35 from outside or the like like the selection signal S. In this case, the calculation contents of the compensation amount calculating means 35 can be flexibly changed at any time by resetting the parameters a to d. Note that the number of parameters is not limited to four, but is arbitrary.

[0052]

Fifth Embodiment A specific configuration of a fifth embodiment of the pump rotation speed control system of the present invention will be described with reference to the drawings. FIG. 5A is an overall block diagram, and FIG.
FIG. 2B is a block diagram of the motor controller 20. This pump rotation speed control system is the third and
The difference from the fourth embodiment is that the main controller 1 issues not only the speed command Rc but also the force command Pc to the motor controller 20, and that the motor controller 20 Control is also performed.

The motor controller 20 is provided with the adjusting means 30 described above in order to perform pressure control as the force control based on the force command Pc using, for example, the pressure detecting means 4a and the pressure Pf which is the detection result. Speed control means 21
And a current control system 24 + 25, a force control system 70 is added. In order to automatically switch from speed control to pressure control, a pressure control unit 71 is provided.
In addition, control system switching means 74 + 75 are also included.
A pressure error calculating unit 72 for calculating a difference ΔP by subtracting the pressure Pf from the force command Pc in order to generate a current command Ic such that the pressure Pf approaches and matches the force command Pc; For example, a current command calculation unit 73 that generates a current command Ic by performing appropriate amplification, integration, and the like on the difference ΔP to perform PI control is provided.

Also, the comparing section 7 which inputs the difference ΔR and the difference ΔP to the control system switching means 74 + 75 and compares the differences.
4 and when the difference ΔR is larger than the difference ΔP based on the comparison result, the current command Ic from the speed control means 21 is selected, and when the difference ΔR is smaller than the difference ΔP, the pressure control means 71 is selected.
Current command Ic from the current control means 24
And a switching unit 75 for sending out to

In this case, the speed command Rc and the force command Pc given from the main controller 1 to the motor controller 20 are simultaneously set to a predetermined positive value from zero. The predetermined value of the speed command Rc corresponds to, for example, the speed of the constant speed feed of the operating member, and the force command Pc corresponds to the thrust to be held when the operating member reaches the operation limit and the reaction force increases. Is done.

Then, at first, since the pressure Pf is low and the difference ΔP is large, the speed control is more effective, and the speed control means 2
1 and the operation of the adjusting means 30, as described above, the speed of the operating member quickly becomes stable in response to the speed command Rc. Then, when the actuating member reaches the actuation limit, the speed Rf drops rapidly while the pressure Pf increases, so that the difference ΔR reverses the difference ΔP, and accordingly the pressure control is now more effective. . And the pressure control means 71
Controls the servo motor 3 so that the thrust of the operating member matches the force command Pc. Since only a small discharge amount Q is required to maintain the pressures in the same state, the liquid pump 4 and the servomotor 3 rotate slowly and stably, and wasteful consumption of electric power is prevented.

Thus, in this system, since the pressure detecting means 4a provided to compensate the discharge amount Q of the liquid pump 4 with respect to the speed command Rc is used, the automatic switching from the speed control to the pressure control is performed in the motor controller 20. It is realized only by modification. Moreover, by utilizing the calculated differences ΔR and ΔP in the speed control means 21 and the pressure control means 71, automatic switching can be performed reliably and appropriately without a specific threshold value.

[0058]

Sixth Embodiment A specific configuration of a sixth embodiment of the pump rotation speed control system of the present invention will be described with reference to the drawings. FIG. 6A is an overall block diagram, and FIG.
FIG. 2B is a block diagram of the motor controller 20. This pump rotation speed control system is the first to
The difference from the fifth embodiment is that a relatively inexpensive electric motor 83 having no feedback of the rotational speed Rf is provided in place of the servo motor 3, and the electric motor The point that the motor driver 29 that supplies the drive current to the motor controller 83 has been replaced with an inverter 82 and the motor controller 81
Is that open control is performed instead of performing feedback control based on the speed Rf and the drive current If.

The motor controller 81 is provided with the above-described adjusting means 30 at the front stage and the signal conversion means 84 at the rear stage. The adjusting means 30 is provided in front of the signal converting means 84, and does not pass the speed command Rc as it is, but passes the speed command Rm corrected by the compensation amount f (Pf, Rc, Tf). The signal conversion means 84 is a conventional inverter control means itself without feedback, and includes, for example, a voltage-controlled oscillation circuit (VCO) using the speed command Rm as a control signal, and the like.
In addition to varying the frequency of the oscillation signal according to m, a three-phase inverter control signal having a phase shifted from the oscillation signal is generated and sent to the inverter 82.
The inverter 82 varies the frequency of the three-phase drive current output to the electric motor 83 according to the control signal received from the signal conversion means 84.

In this case, the driving of the liquid pump 4 is performed not by the servo motor 3 but by the electric motor 83, and the control is performed by open control instead of feedback control. They are common in that they perform variable control, and their overall operating conditions and issues are also generally common to servomotors. Therefore, also in this case, by introducing the speed command Rc adjusting means 30 between the main controller 1 and the signal converting means 84,
Almost the same advantages as those of the above-described embodiments can be obtained.

[0061]

Seventh Embodiment A specific configuration of a seventh embodiment of the pump rotational speed control system according to the present invention will be described with reference to the drawings. FIG. 7A shows the motor controller 20.
FIG. 7B is a block diagram of the first half of FIG.
It is a block diagram of. This pump rotation speed control system differs from those of the first to fifth embodiments in that the combining means 33 in the adjusting means 30 is replaced by a combining means 91. The correction amount calculating means 31 may be the same.

The synthesizing means 91 is provided not on the speed command Rc side but on the speed Rf side.
, That is, the subtraction circuit for subtracting the compensation amount f (Pf, Rc, Tf). Then, the output Rg is used as an inverted input of the speed error calculation unit 22 instead of the speed Rf.
In this case, the value of the speed command Rc itself is not directly increased or decreased, but by increasing or decreasing the speed Rf to be compared in the opposite direction, the same result can be obtained from the viewpoint of the difference ΔR and thereafter. It can be said that the speed command Rc is being adjusted. In this case, the same operation results and effects as described above can be obtained.

[0063]

[Others] In the above embodiment, the case where the operating portion 5 is a hydraulic actuator such as a cylinder has been described. However, the application of the present invention is not limited thereto, and a hydraulic motor or another actuator may be used. For example, a combination of a rotation / linear motion conversion mechanism such as a ball screw and a pressurizing mechanism such as a ram cylinder, and a swing mechanism connected via a reduction gear or the like are often used. In addition, its application is, for example, in addition to a press device and a die cast machine, a glass forming machine,
It is possible in various fields, such as a machine tool, an injection molding machine, a press-fitting part mounting device, a transfer device, and a robot arm. Further, the liquid is widely used for hydraulic pressure and is easy to use.However, the liquid is not limited to the hydraulic pressure.For example, depending on the characteristics and restrictions of the application, water, a chemically synthesized liquid, and a mixed liquid of different kinds of liquids are used. Alternatively, a mixed liquid of powder and granules may be used.

As for the other components, a permanent magnet synchronous motor or the like is used as the electric motor 3 or 83 in the brushless DC servo motor, and a squirrel-cage induction motor is frequently used as the induction motor. The speed control means 21 and the pressure control means 71 include, in addition to the PI control described above,
A control method combining PID control, vector control, and dq conversion is appropriately adopted, and the method is embodied by a general design technique using appropriate hardware and software. The motor driver 29 has a three-phase voltage-type PWM that can efficiently output large power and has good controllability.
An inverter or the like is preferred, and a Hall element or the like having high responsiveness and high accuracy is frequently used in the current detection unit of the drive current If.

Further, although the configuration of each embodiment is shown in the form of an analog circuit, the adjusting means 30 of the motor controller 20 and other circuits are provided with an A / D conversion circuit for inputting the pressure Pf and the rotation speed Rf. A circuit may be added and a digital circuit may be formed for each corresponding block.
Alternatively, a microprocessor system may be used as the motor controller 20 to process the function of the corresponding circuit by a program. In the case of digitization in this way, for example, in the function calculation of the correction amount calculating means 31, addition and multiplication may be repeated every time. The data may be stored in an array of a memory or the like if the calculation is performed by computer program processing.

Further, in each of the above embodiments, the main controller 1 and the motor control electronic circuit 2 are separated into separate units. However, the present invention is not limited to this, and the main controller 1 and the motor control electronic circuit 2 are separated. The circuits 2 may be integrated in the same unit, or the main controller 1 and the motor controller 20 may be the same unit. Alternatively, they may be integrated into the same computer system. In such a case, the speed command Rc is generated in the motor control electronic circuit 2 and passed between boards, between analog or digital circuit blocks, or between routines. Sometimes.

In each of the above embodiments, the liquid pump 4
Although the presence of a directional control valve, a relief valve, or the like in the liquid flow path from the to the operating unit 5 is not explicitly described, the present invention does not deny the existence thereof, and the directional control valve or the like may be incorporated. good. Further, various hydraulic circuits and the like may be connected as appropriate for reciprocating motion of the operating member, ensuring safety, and the like, or as necessary.

In the fifth embodiment, the force control is performed using the pressure Pf for the adjusting means 30. However, the force control is limited to such a pressure control. Instead, it may be performed based on the pressure detected at another location. Furthermore, the operation limit of the operation part 5 is the cylinder end or the filling of the mold with the filler,
In the case where the force control is such that the thrust or the like at such an operation limit is controlled by feedback, a load cell, a torque meter, or the like is also used as the force detecting means.

[0069]

As is apparent from the above description, in the pump rotation speed control system according to the first solution of the present invention, the motor and the pump are controlled in consideration of the leakage amount corresponding to the pump discharge pressure. The advantage of compensating the rotational speed of the pump and compensating for the speed command is that the pump speed control system that accurately corresponds to the speed command and the flow rate can be easily realized. There is.

In the pump rotational speed control system according to the second solution of the present invention, not only the pressure but also the rotational speed are taken into account when compensating for the amount of leakage. There is an advantageous effect that a more accurate pump rotation speed control system can be easily realized.

Furthermore, in the pump rotation speed control system according to the third solution of the present invention, not only the pressure but also the liquid temperature is taken into account when compensating for the leakage amount, so that the speed command and the flow rate can be adjusted. There is an advantageous effect that a more accurate pump rotation speed control system can be easily realized.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a pump rotation speed control system according to the present invention.
In the embodiment, (a) is an overall block diagram, (b) is a block diagram of a motor controller, (c) is a block diagram of an adjusting means, and (d) is a graph in which the horizontal axis indicates the discharge pressure of the pump and the vertical axis indicates the discharge. 6 is an operation characteristic graph showing amounts and the like.

FIG. 2 shows a second embodiment of the pump rotation speed control system of the present invention.
(A) is a block diagram of an adjusting means,
(B) is an operation characteristic graph in which the horizontal axis indicates the discharge pressure of the pump and the vertical axis indicates the discharge amount and the like.

FIG. 3 shows a third embodiment of the pump rotation speed control system according to the present invention;
(A) and (b) of the embodiment are all block diagrams.

FIG. 4 shows a fourth embodiment of the pump rotation speed control system according to the present invention.
(A) and (b) are block diagrams of adjusting means in the embodiment.

FIG. 5 shows a fifth embodiment of the pump rotation speed control system according to the present invention.
1A is an overall block diagram and FIG. 2B is a block diagram of a motor controller according to an embodiment.

FIG. 6 shows a sixth embodiment of the pump rotation speed control system of the present invention.
1A is an overall block diagram and FIG. 2B is a block diagram of a motor controller according to an embodiment.

FIG. 7 shows the seventh embodiment of the pump rotation speed control system according to the present invention.
FIG. 3A is a block diagram of a first half of a motor controller, and FIG. 3B is a block diagram of an adjusting unit.

8 (a) is a block diagram of a motor controller, FIG. 8 (c) is a block diagram of a motor controller, and FIG. 8 (c) shows a discharge pressure of a pump on a horizontal axis and a discharge amount on a vertical axis. It is an operation characteristic graph shown by taking the like.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main controller (sequence control means for application) 2 Electronic circuit for motor control (motor control drive device) 3 Servo motor (electric motor of feedback control) 4 Liquid pump (hydraulic pump) 4a Pressure detecting means (pressure sensor, pressure gauge) 4b Temperature detecting means (temperature sensor, thermometer, liquid temperature detecting means) 5 Actuator (actuator such as hydraulic motor or cylinder unit) 20 Motor controller (electronic control device for electric motor) 21 Speed controlling means Reference Signs List 22 speed error calculator 23 current command calculator 24 current control means (torque control means) 25 signal conversion means (PWM, pulse width modulation means) 29 motor driver (drive device for electric motor) 30 adjustment means 31 compensation amount calculation means ( Function calculation means 33 Combining means (addition means, subtraction means, correction amount / compensation amount Means) 34 Switching means (compensation calculation function selection switching means, compensation content variable means) 35 Compensation amount calculation means (function calculation means, correction / compensation content variable means) 70 Force control system 71 Pressure control means (force control means) 72 Pressure Error calculation unit 73 Current command calculation unit 74 Comparison unit (control system switching unit) 75 Switching unit (control system switching unit) 81 Motor controller (electronic control device of electric motor) 82 Inverter (driver for open control with respect to drive current) 83 Electric Motor (motor with open control on drive current) 84 Signal conversion means (VCO, voltage controlled oscillation circuit, etc.) 91 Synthesis means (feedback amount adjustment means, emphasis means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuyuki Kihara 2-16-46 Minami Kamata, Ota-ku, Tokyo F-term in Tokimec Co., Ltd. (Reference) 3H045 AA09 AA12 AA24 AA34 BA19 BA28 CA03 CA19 DA07 EA38

Claims (7)

[Claims] In a pump rotation speed control system for driving a liquid pump with a servomotor, a pressure detecting means for detecting a discharge pressure of the liquid pump, and a compensation amount relating to a discharge amount of the liquid pump based on the detection result. A pump rotation speed control system comprising: a compensation amount calculating means for calculating; and a synthesizing means for receiving a speed command to the servomotor and correcting with the compensation amount. 2. The pump rotation speed according to claim 1, wherein said compensation amount calculating means calculates said compensation amount based on a detection result of said pressure detecting means and said speed command. Control system. 3. The liquid pump according to claim 1, further comprising a temperature detecting means provided for the liquid pump or a flow path to which the liquid is discharged, and measuring a temperature of the liquid pump. The pump rotation speed control system according to claim 1, wherein the system is used for calculation. 4. The pump rotation speed control system according to claim 1, further comprising a compensation content varying means for changing the computation content of said compensation amount calculating means. 5. A detection result and a force command in response to a detection result of the pressure detection means or a detection result of a separately provided force detection means for detecting a force generated by the operation of the liquid pump. The pump rotation speed control system according to any one of claims 1 to 4, wherein force control based on the speed command and speed control based on the speed command are selectively performed. 6. A pump rotation speed control system according to claim 1, wherein an electric motor provided in place of said servo motor is driven by an inverter according to said speed command. . 7. The apparatus according to claim 1, wherein said synthesizing means adjusts a feedback amount of the rotation speed of said servomotor when compensating said speed command.
A pump rotation speed control system described in any one of the above.