JPH09198108A - Actuator controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve control efficiency in actuator control using genetic algorithm (GA). SOLUTION: A shock absorber 10 is controlled by an actuator 16. The attenuating coefficient of the absorber 10 to be controlled by the actuator 16 is calculated by using GA by a control means 22. The control means 22 generates the control parameter system of a new generation by means of GA and judges the direction of present control based on the power spectrum of acceleration 24 on a spring. When control in the direction of raising attenuating force is judged to be necessary as attenuating force is short in present control, and a new control parameter system generated based on GA does not exist in the direction of raising attenuating force. The trial and evaluation through the use of the new generation is prohibited, thereby prohibiting unnecessary trial to improve control efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator control device, and more particularly to a device for optimally controlling an actuator according to a situation using a plurality of control parameters.

[0002]

2. Description of the Related Art Conventionally, a technique for adjusting a damping coefficient of a shock absorber incorporated in a suspension of a vehicle such as an automobile has been proposed. For example, in Japanese Patent Application Laid-Open No. 5-294122 previously proposed by the applicant of the present application, the skyhook damping coefficient is C based on the skyhook damper theory,
An apparatus for controlling the actual damping coefficient C * of the shock absorber according to C · Zd / Yd, where Zd is the vertical speed on the spring, and Yd is the vertical relative speed between the sprung and unsprung springs. It is disclosed that the damping coefficient is corrected based on the vibration input component from the road surface.

[0003]

As described above, by making the damping coefficient variable instead of a fixed value, it is possible to cope with changes in road surface conditions to some extent, but the damping force of the shock absorber is applied to all road surfaces. Optimal setting is difficult. In particular, the mechanical parts such as absorbers change their characteristics due to deterioration over time, so the damping coefficient does not always remain optimal even under the same road conditions. Adjustment is not easy by itself.

Therefore, recently, it has been considered to adjust a control parameter for damping force control using a genetic algorithm (hereinafter referred to as GA). GA is a method of searching for an optimum solution by analogy with biological evolution, and is generally performed through the following processing steps.

(1) Generation of initial population (2) The following loop processing is performed until the end condition is satisfied: i) Fitness evaluation ii) Selection iii) Generation of new generation by crossover or mutation By generating and performing the evaluation and leaving only the control parameters having excellent evaluation values, it is possible to find an optimal solution regardless of the road surface condition and changes with time, although the response is slightly inferior.

However, when controlling the damping force of the suspension using such a GA, a new generation of control parameters must always be generated and the generated new generation must be evaluated. Although the control parameters currently used have achieved a sufficiently satisfactory level of control effect, there is a problem that the control efficiency is not high because a new control parameter is generated and evaluated. Also, judging from the current excess or deficiency of damping force,
In some cases, new control parameters for increasing the damping force were generated and evaluated even though the damping force originally had to be reduced.

The present invention has been made in view of the above problems of the prior art, and is capable of coping with environmental changes and deterioration with time, and efficiently setting optimum control parameters to provide various actuators such as suspension control actuators. An object is to provide an actuator control device that can be controlled.

[0008]

In order to achieve the above object, a first invention is an evaluation means for quantitatively evaluating the quality of control when actuator control is executed using a control parameter system, and the control parameter. Actuator control device having change means for changing the system to a new control parameter system and selection means for comparing the evaluation values of the control parameter system before and after the change and selecting the control parameter system having a better evaluation value In the control direction determining means for determining the direction in which the actuator should be controlled, and if the control by the current control parameter system is determined to be within a predetermined allowable range, the new control is performed. And a control means for prohibiting actuator control and evaluation using a parameter system.

In order to achieve the above-mentioned object, the second aspect of the present invention provides a new evaluation means for quantitatively evaluating the quality of control when the actuator control is executed using the control parameter system, and the control parameter system. In an actuator control device having a changing means for changing to a control parameter system and a selecting means for comparing the evaluation values of the control parameter system before and after the change and selecting a control parameter system having a better evaluation value, When the control direction determining means for determining the direction to be controlled and the control direction of the new control parameter do not match the control direction determined by the control direction determining means, the new control parameter system is set. It is characterized by having a control means for prohibiting the actuator control and evaluation used.

Further, in order to achieve the above object, in the third invention, in the second invention, the control means includes the changing means for changing the new control parameter into a new control parameter system. It is characterized by controlling.

Further, in order to achieve the above object, a fourth invention is the first, second or third invention, wherein the actuator is a suspension damping force control actuator of a vehicle, and the control parameter system is It is characterized by being an attenuation coefficient.

In order to achieve the above object, in a fifth aspect based on the fourth aspect, the control direction determining means determines the control direction based on the energy spectrum of the sprung acceleration of the suspension. Is characterized by.

Further, in order to achieve the above object, the sixth invention is characterized in that, in the fourth invention, the evaluation means evaluates the quality based on an integrated value of the sprung acceleration of the suspension. .

Further, in order to achieve the above object, a seventh
Of the invention, an evaluation means for quantitatively evaluating the quality of control when actuator control is executed using a control parameter system, a changing means for changing the control parameter system to a new control parameter system, and a before and after change. In the actuator control device having a selection means for comparing the evaluation values of the control parameter system of and selecting the control parameter system having a better evaluation value, the current evaluation value of the control parameter system is within a predetermined allowable range. When it is determined, the control means for inhibiting the actuator control and the evaluation using the new control parameter system is provided.

[0015]

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

FIG. 1 shows a block diagram of this embodiment. The variable damping force type shock absorber 10 is configured to include a piston 12 and a main body 14, and is switched from hard (large damping force) to soft (small damping force) in multiple stages by a control actuator 16 fixed to the vehicle body. It is designed to be used. The actuator 16 has a vertical speed Zd on the spring detected by the sprung speed detector 18 and a vertical direction between the sprung and unsprung parts detected by the relative speed detector 20 with the skyhook damping coefficient as C. Based on the relative speed Yd of the control means 2 so that the actual damping coefficient C * of the shock absorber 10 becomes C · Zd / Yd.
2 is controlled. The control unit 22 is configured to include a GA controller and a memory, and the GA controller generates a new generation described later.
The evaluation and selection are performed, the direction in which the actuator should be controlled is determined, and the population is stored in the memory. The GA controller is specifically composed of a CPU, a ROM storing a GA program and a control direction determination program, a RAM, an input / output interface, and the like. The sprung speed detector 18 calculates the speed by time-integrating the sprung acceleration detected by the sprung acceleration detector 24. Also,
The sprung acceleration itself is also supplied to the control means 22 and is used in the control direction determination process as described later.

FIG. 2 shows an example of an individual group used in this embodiment and stored in the memory. Each individual,
That is, the control parameter system is CS, C1, C2, ...
, Cn, which is composed of (n + 1) control parameters, CS is a skyhook damping coefficient, and C1, C
2, ..., Cn are damping factors of each stage of the absorber. The actual damping coefficient is calculated by C * = CS · Zd / Yd,
The damping coefficient that best matches this actual damping coefficient is C1, C2,
..., Cn is selected and controlled. In the present embodiment, each damping coefficient is represented by 8 bits. C1 is the soft mode in which the damping force is the smallest, and C2, C3, ... Becomes the hard mode in which the damping force increases. Dozens of such individuals are prepared, and a new generation control parameter system is generated by appropriately crossing or mutating these individuals. The evaluation value is given to each individual, and the evaluation value as a set is stored in the memory together with each control parameter of the individual.

FIG. 3 shows a processing flowchart of the control means 22. First, as an initial setting, the previous evaluation result Res (evaluation calculation and evaluation result will be described later) is once set as the current evaluation result (S10).
1), the timer is reset to 0 (S102). next,
Skyhook control is actually executed using a certain control parameter system (S103). That is, using a certain control parameter system (CS, C1, C2, ..., Cn), the actual damping coefficient C * required for the absorber is first calculated by C * = CS.Zd / Yd, and this actual damping is calculated. The damping coefficient closest to the coefficient C * is selected from C1, ..., Cn to drive the actuator 16. Then, while such skyhook control is being performed, the control means 22 is a ROM.
The control direction determination program stored in is executed. This control direction determination program is performed based on the energy spectrum of sprung acceleration (S104).

FIG. 9 shows the relationship between the energy spectrum of sprung acceleration and the damping force. In the figure, the horizontal axis represents frequency and the vertical axis represents power spectrum density (PSD) of sprung acceleration. Also, the solid line in the figure is the PSD when the absorber damping force is small, and the alternate long and short dash line is the PSD when the absorber damping force is large. When the damping force is large, near the sprung resonance point [0.
The power of the frequency band of 2 to 2 Hz] decreases, and [2 to 8H
The power in the z] frequency band increases. On the other hand, when the damping force is small, the power of the frequency band of [0.2 to 2 Hz] increases and the power of [2 to 8 Hz] decreases. As described above, since the power spectrum changes depending on the magnitude of the damping force, the present embodiment focuses on this fact and detects the power spectrum to determine the magnitude of the power in a specific frequency band, thereby controlling the current control. It is determined whether the damping force is insufficient or the damping force is excessive. In FIG. 9, the frequency is 20
Although the PSD up to Hz is shown, at 20 Hz or higher, the PSD changes greatly depending on the switching frequency of the damping coefficient of the absorber rather than the magnitude of the damping force. FIG. 10 shows the state of PSD with a frequency of 20 Hz or higher. In the figure, the solid line indicates the case where the switching frequency is high and the alternate long and short dash line indicates the case where the switching frequency is low. It can be seen that when the attenuation coefficient is switched frequently, the power increases in the frequency region of 20 Hz or higher. Therefore, in the present embodiment, in order to realize a more comfortable riding comfort, the magnitude of the power of 20 Hz or higher is also determined to determine the control direction. However, this 2
The determination of the power of 0 Hz or higher is a secondary one, and 0.
It is performed after determining the power of 2 to 8 Hz.

Returning to FIG. 3 again, if PSD processing for determining the control direction is performed as described above (S10)
4) Next, the process proceeds to the evaluation calculation process for evaluating the currently used individual, that is, the control parameter system (S10).
5). This evaluation calculation is an essential process for GA and is for determining whether or not the individual is excellent. This evaluation calculation can be performed by various methods, but in the present embodiment, it is evaluated by the integral value of the sprung acceleration within a predetermined time. That is, the smaller the integrated value, the better the control. A timer is advanced to perform the frequency analysis and the evaluation calculation (S106), and the sampling time Csmp (0.2 Hz to 50 Hz) required to obtain the PSD is obtained.
Since about 10 seconds have passed since it is calculated until (S1
07), the control means 22 sets the calculated evaluation value of the present individual to R
Store in memory as es. Then, the total sum of all the energies of the PSD is calculated (S108), and the ratio of each frequency band is obtained using the total sum of all the energies (S10).
9).

FIG. 11 shows a process for obtaining the total sum of all energies, and P for frequencies from 0.2 Hz to 50 Hz.
The sum Σ can be obtained by integrating SD. The shaded area in the figure is the total sum. Further, FIG. 12 shows a process of obtaining the ratio of each frequency band, and the frequency [0.2 to 2H
z] is an integrated value of energy, β is an integrated value of energy of a frequency [2 to 8 Hz], and γ is an integrated value of energy of a frequency [20 to 50 Hz]. Thus, the ratio of each frequency band can be obtained. In this embodiment, these ratios are A (= α / Σ), B (= β / Σ), and C (= γ / Σ), respectively.

After obtaining the ratio of each frequency band in this way, the GA controller of the control means 22 shifts to the individual erasing process (S110). This individual erasing process is a process of deleting individuals having a poor evaluation result from the group of individuals, and selectively leaving only individuals having an excellent evaluation result.

FIG. 4 shows a flowchart of this individual erasing process. First, it is determined whether the value of the flag flag is 1 (S201). This flag flag is for identifying whether or not the generated new generation control parameter system matches the current control direction, and when it is determined to match the current control direction as described later. Is given Flag = 1. Therefore, if the flag is not 1, specifically, flag = 0, the new generation does not improve the control, so the new generation is deleted (S203). Further, when flag = 1, the evaluation calculation result of this new generation has already been obtained in S105, so the evaluation values of the individual group stored in the memory and the individual of this new generation are compared. Has the highest evaluation value,
That is, the one with the largest integral value of the sprung acceleration and the poor controllability is deleted (S202). As a result, only the highly evaluated population is left in the memory.

When the individual erasing process is completed as described above, a new generation individual, that is, a new control parameter system is subsequently generated using GA (S111). This new generation generation is generated by crossing (or mutating) the individual groups having excellent evaluation values stored in the memory with each other. Here, the crossover is, for example, C1 of the individual A is (00000010) having 8 bits and C2 is (00
000110), and the C1 of the individual B is (000000
When C2 is (00000101) in 11), the C1 of the new generation individual is C1 of the individual A (00000010)
And C2 is set as C2 (00000101) of the individual B.

When the generation of the new generation by the GA is completed, the evolution direction determination process is then executed (S112). This evolution direction determination processing determines whether or not the proportion of each frequency band obtained in S109, that is, the newly generated new generation matches the direction to be controlled. FIG.
6, 7 and 8 show detailed flowcharts of this evolution direction determination processing. First, in FIG. 5, the magnitude A of the ratio A at the frequency [0.2 to 2 Hz] and a predetermined threshold value CAmax are compared (S301). This threshold value CAmax is a ratio of power for determining that the damping force is insufficient, and if it is larger than this threshold value, the current control is determined to be insufficient damping force (see FIG. 9). . If it is determined that A> CAmax, then the ratio B at the frequency [2 to 8 Hz] and the predetermined threshold value CB.
The size is compared with max (S304). This threshold value CBmax is a ratio of power for determining excessive damping force, and if it is larger than this threshold value, the current control is determined to be excessive damping force (see FIG. 9). Therefore, B
If CBmax, it is determined that the damping force is still insufficient, and then the current evaluation result Res and the previous evaluation result Res
The magnitude comparison of the value obtained by adding the predetermined value Cres to Old is performed (S305). This judgment is for judging whether or not the current individual has sufficiently satisfactory controllability, and the evaluation value of the current individual is large, that is, it is determined that the current individual has poor control. In this case, the control means 22 determines that the current control should be controlled in the direction of increasing the damping force, and shifts to the processing shown in FIG.

On the other hand, if NO in any of the processes of S301, S304, S305, that is, if it is determined that the direction in which the actuator should be controlled is not the direction in which the damping force is increased, then the above-mentioned threshold value CBmax is set. It is used to determine whether the damping force is excessive (S302). B> CBm
If it is ax, there is a possibility that the damping force is excessive, so it is next determined whether or not A <CAmax (S30).
6). If A <CAmax, it can be judged that the current damping force is excessive. Therefore, similarly to S305, it is further determined whether the current evaluation value is worse than the allowable range (S307). When it is determined that the current individual exceeds the allowable range and the evaluation is poor, the control unit 22 determines that the current damping force must be controlled in the direction of decreasing and shifts to the processing shown in FIG. 7. .

On the other hand, when the damping force is neither insufficient nor excessive, and the current evaluation value is within the allowable range, all of S30.
The process shifts to the process of 3 and the frequency is [20 to 50 Hz] here.
The ratio C and the predetermined threshold value CCmax are compared. This threshold value CCmax is a power ratio for determining whether the attenuation coefficient is switched frequently or not, and when it is larger than this threshold value, it is determined that the switching frequency is high (see FIG. 10). Process), and shifts to the processing shown in FIG. If it is determined that the frequency is low, the evolution direction determination process is terminated and the process shown in FIG.
In step S113, the flag is set to 0. This flag = 0 means that the new generation does not improve the control as described above, and this is because the results obtained by the current individual control are sufficiently satisfactory, and the new generation is tried. Because there is no need to do it. Therefore, when flag = 0 is set and the processing of the transition to S101 is performed again, the skyhook control in S103 is not the new generation generated in S111, and the damping force control is continuously performed using the current individual. Will be done.

Hereinafter, when it is determined that the damping force is insufficient and the control must be in the direction of increasing the damping force (FIG. 6), it is determined that the damping force is excessive and the control is in the direction of decreasing the damping force. These processes will be described separately in the case where it is determined that there is no need (FIG. 7) and the case where it is determined that the damping force is not excessive or insufficient but the switching frequency is too high (FIG. 8).

FIG. 6 is a processing flowchart for increasing the damping force. First, the control unit 22 checks the new generation individual generated in S111, that is, the control parameter system, and determines whether or not this new generation is in the direction of increasing the damping force (S401). This determination can be made based on the values of the attenuation coefficients C1, ..., Cn of each stage of the new generation individuals. For example, assume that C1 and C2 are actually used among the attenuation coefficients of the current individual. Then, the control means 2
2 is C1 and C among the control parameters of the new generation individuals.
The values of 2 are checked to determine if these values are decreasing. If these values are decreasing, the harder damping coefficient is selected more often, and as a result, it can be determined that the damping force is increasing as a new generation individual. . In this way, when it is determined that the new generation is in the direction of increasing the damping force, it means that this new generation is a desirable new generation for better control, so each control parameter is set to this new generation. Set (S402) and set flag to 1 (S40)
3). Therefore, the next skyhook control will be performed in this new generation. On the other hand, if it is determined that the new generation is not in the direction of increasing the damping force, this new generation does not match the control direction, so it is not adopted, and the process returns to the processing of S111 to regenerate a new new generation. . This makes it possible to prohibit trial and evaluation of the new generation even if the control direction of the new generation does not match the control direction currently required.

FIG. 7 is a processing flowchart for decreasing the damping force. First, the control unit 22 checks the new generation individual generated in S111, that is, the control parameter system, and determines whether or not this new generation is in the direction of decreasing the damping force (S501). This determination can also be made based on the values of the attenuation coefficients C1, ..., Cn of each stage of the new generation individuals. For example, assume that C1 and C2 are actually used among the attenuation coefficients of the current individual. Then, the control means 2
2 is C1 and C among the control parameters of the new generation individuals.
The values of 2 are checked to determine if these values are increasing. When these values are increased, the softer damping coefficient is selected more often, and as a result, it can be determined that the damping force is decreasing as a new generation individual. . In this way, when it is determined that the new generation is in the direction of decreasing the damping force, this new generation is a desirable new generation for better control, so each control parameter is set to this new generation. Set (S502) and set flag to 1 (S50)
3). Therefore, the next skyhook control will be performed in this new generation. On the other hand, if it is determined that the new generation is not in the direction of decreasing the damping force, this new generation does not match the control direction and thus is not adopted, and the process returns to the processing of S111 and a new new generation is generated again. . This makes it possible to prohibit trial and evaluation of the new generation even if the control direction of the new generation does not match the control direction currently required.

FIG. 8 is a processing flowchart for reducing the switching frequency. First, the control means 22 uses S1
The new generation individual generated in step 11, ie, the control parameter system is checked to determine whether or not this new generation tends to reduce the switching frequency (S601). This determination can be made by the value of the damping coefficient CS of the new generation.
That is, since this attenuation coefficient functions as a gain as can be seen from C * = CS · Zd / Yd, the switching frequency increases as this value increases. Therefore, when the damping coefficient CS of the new generation is smaller than the current damping coefficient, it can be determined that the new generation tends to reduce the switching frequency. In this way, when it is determined that the new generation is in the direction of decreasing the switching frequency of the damping coefficient, each control parameter is set to this new generation (S
602) and the flag is set to 1 (S603). Therefore, the next skyhook control will be performed in this new generation and the evaluation calculation will be performed. On the other hand, when it is determined that the new generation is not in the direction of decreasing the switching frequency, the process returns to S111 and a new new generation is generated again.

As described above, in this embodiment, the excess or deficiency of the damping force is determined based on the power spectrum of the sprung acceleration, and the new generation to be tried to set the power spectrum to the desired spectrum is selected in advance. Therefore, it is possible to reliably prevent the trial of a new generation that does not improve the controllability. Further, even when it is determined that the current controllability is within the allowable range based on the evaluation value, the new generation is not tried, and therefore the efficiency of controllability is not unnecessarily reduced.

In this embodiment, an actuator for controlling the suspension damping force of the vehicle has been described as an example. However, the point of the present invention is that before the generated new generation is tried, the new generation is controlled. Determine whether it is desirable to improve, prohibit trial and evaluation if it is not desirable, and prohibit new generation trial and evaluation even when the current controllability is within the acceptable range. Therefore, it goes without saying that the present invention can be applied to any actuator within the scope of the present invention.

[0034]

As described above, according to the present invention, a new control parameter system is not uniformly controlled and evaluated, but a new control parameter is set only when it is considered necessary for the current control. Since the system is used, it is possible to cope with various environments and deterioration over time without lowering the control efficiency.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a population of the same embodiment.

FIG. 3 is an overall processing flowchart of the same embodiment.

FIG. 4 is a detailed flowchart of individual deletion processing in FIG.

FIG. 5 is a detailed flowchart of the evolution direction determination process in FIG.

FIG. 6 is a processing flowchart when the damping force is insufficient.

FIG. 7 is a processing flowchart when the damping force is excessive.

FIG. 8 is a processing flowchart when the switching frequency is high.

FIG. 9 is a graph showing the relationship between damping force and PSD.

FIG. 10 is a graph showing the relationship between switching frequency and PSD.

FIG. 11 is an explanatory diagram showing a total sum of all energies.

FIG. 12 is an explanatory diagram showing the ratio of each frequency band.

[Explanation of symbols]

10 shock absorbers, 16 actuators, 2
2 Control means.

Claims (7)

[Claims] 1. An evaluation means for quantitatively evaluating the quality of control when actuator control is executed using a control parameter system, a changing means for changing the control parameter system to a new control parameter system, and a change before and after the change. After comparing the evaluation values of the control parameter system,
In the actuator control device having a selecting means for selecting a control parameter system having a better evaluation value, a control direction determining means for determining a direction in which the actuator should be controlled, and a control direction determining means for determining a current control parameter system. An actuator control device comprising: a control unit that prohibits actuator control and evaluation using the new control parameter system when the control is determined to be within a predetermined allowable range. 2. An evaluation means for quantitatively evaluating the quality of control when actuator control is executed using a control parameter system, a changing means for changing the control parameter system to a new control parameter system, and a change before and after the change. After comparing the evaluation values of the control parameter system,
In an actuator control device having a selection means for selecting a control parameter system having a better evaluation value, a control direction determination means for determining a direction in which an actuator should be controlled, and a control direction of the new control parameter is An actuator control device comprising: a control unit that prohibits actuator control and evaluation using the new control parameter system when the control direction determined by the control direction determination unit does not match. 3. The actuator control device according to claim 2, wherein the control unit controls the changing unit to change the new control parameter into a new control parameter system. . 4. The method according to claim 1, 2 or 3.
In the actuator control device described above, the actuator is a suspension damping force control actuator for a vehicle, and the control parameter system is a damping coefficient. 5. The actuator control device according to claim 4, wherein the control direction determination means determines a control direction based on an energy spectrum of sprung acceleration of the suspension. 6. The actuator control device according to claim 4, wherein the evaluation means evaluates pass / fail based on an integrated value of sprung acceleration of the suspension. 7. An evaluation means for quantitatively evaluating the quality of control when actuator control is executed using a control parameter system, a changing means for changing the control parameter system to a new control parameter system, and a change before and after the change. After comparing the evaluation values of the control parameter system,
In the actuator control device having a selection means for selecting a control parameter system having a better evaluation value, if the evaluation value of the current control parameter system is determined to be within a predetermined allowable range, An actuator control device comprising: a control unit that prohibits actuator control and evaluation using a control parameter system.