JPS6250276A - Power steering device - Google Patents

Abstract

PURPOSE:To improve the safety in the traveling on a mountain road by installing a controller for controlling an auxiliary force which an auxiliary force generating means outputs according to the sensitivity and setting the sensitivity in the traveling on a mountain road. CONSTITUTION:The control pattern of the electric current applied onto the solenoid 27 and 49 of solenoid valves 20 and 48 is memorized as characteristic map into the ROM 63 of an electronic controller 60. In the control pattern I in said characteristic, the electric current value IB applied onto the solenoid 27 is increased for the increase of the car speed V, and the bypass flow rate of a power cylinder 15 is increased and a steering wheel is set heavier at high car speed. While, in the control pattern II, the degree of variation of the electric current quantity IA applied onto the solenoid 49 for the increase of the steering angle theta is set larger in comparison with that in the control pattern I, and the operation of the steering wheel becomes heavier in the traveling on a mountain road in comparison with the traveling on a city road as the steering angle increases.

Description

[Detailed description of the invention] [Field of industrial use]

The present invention relates to a power steering device that improves the steering feeling of an automobile regardless of the driving environment of the automobile.

[Prior art]

A power steering device for an automobile is a device that generates an auxiliary steering force in proportion to the magnitude of manual torque input to a steering shaft of an automobile, thereby reducing the manual torque required for steering. The sensitivity, which is the ratio of auxiliary steering force to manual torque, can be varied depending on vehicle speed, steering angle, steering angular velocity, coefficient of friction between the road surface and the steered wheels, etc., so that the steering sensation is optimal regardless of driving conditions. Proposed. Furthermore, a device has been proposed in which sensitivity characteristics related to vehicle speed, steering angle, steering angular velocity, etc. given in advance are manually selected to obtain an appropriate steering feeling.

[Problems to be solved by the invention]

The optimal sensitivity characteristics that are safe for the driver also change depending on the driving environment of the car. For example, the optimal sensitivity characteristics should be different between driving in a city and driving in a mountainous area. However, in order to achieve control suitable for these environments using conventional devices, the driver had to judge the driving conditions such as city driving, mountain driving, etc. and manually switch the sensitivity characteristics. Manually switching the sensitivity characteristics to obtain steering characteristics suitable for various driving environments complicates the operation and causes operational errors. Therefore, the usability of the device was not good. It is also conceivable to measure the dispersed state of the steering angle, distinguish between city driving and mountainous driving based on the dispersed state, and control the auxiliary steering force with a fixed sensitivity characteristic corresponding thereto. This sensitivity characteristic may be such that when driving in urban areas, the sensitivity is set high and the steering is made light to facilitate driving operations, while when driving in mountainous areas, the sensitivity is set low and the steering is made heavy for safety reasons. There are some characteristics that can be considered. However, while the heavy steering wheel provides stability when driving in mountainous areas, there is a problem in that driving in mountainous areas for a long time can make the driver feel tired. The present invention solves these problems by automatically detecting mountainous driving conditions, controlling the auxiliary steering force using sensitivity characteristics for mountainous driving, and detecting mountainous driving conditions for a certain period of time. By increasing the sensitivity and lightening the steering wheel operation when the driver is accustomed to mountain driving, the aim is to prevent driver fatigue from steering wheel operation during mountain driving and improve the steering feel. shall be.

[Means to solve the problem]

The structure of the invention intended to solve the above problems is as follows, and the concept thereof is illustrated in FIG. an auxiliary force generating means 4 that generates an auxiliary force that assists the steering force of the automobile in response to a control signal from the control device 1; a steering angle sensor 2 that detects the steering angle of the steering wheel of the automobile; and a steering angle sensor 2 that detects the steering angle of the steering wheel of the automobile. A distributed state detection unit 3 that determines the distributed state of the steering angle of the steering wheel from the output signal, and a ratio of the auxiliary force to the manual torque input to the steering wheel of the automobile according to the distributed state determined by the distributed state detection unit 3. A power steering device comprising: a control device 1 that controls the auxiliary force output from the auxiliary force generating means 4 according to the sensitivity by changing a sensitivity, the control device 1 comprising: In areas other than the operating area of the mountain driving determination unit 6 and the sensitivity characteristic modulation unit 7, which determines that the vehicle is traveling in a mountainous area from the dispersion state of the steering angle detected by the state detection unit 3. , a sensitivity characteristic basic section 5 that determines the sensitivity according to the dispersion state of the steering angle determined by the dispersion state detection section 3; and output signals of the mountain driving determination section 6 are input, and the vehicle is detected. When it is determined that the vehicle is in a mountain driving state, after the mountain driving introduction section, which is a predetermined period after entering the mountain driving state, has elapsed, the sensitivity is gradually increased from the sensitivity at the time when the mountain driving introduction section has elapsed to a predetermined value. Sensitivity characteristic modulator 7 that maintains the predetermined value
and an auxiliary force control unit 8 that controls the auxiliary force output by the auxiliary force generating means 4 according to the sensitivity characteristics output from the sensitivity characteristic basic unit 5 and the sensitivity characteristic modulation unit 7. qS・sign. In addition, as a desirable embodiment, if there is a short city driving condition between two mountain driving conditions, even if the mountain driving condition is newly entered, the steering wheel operation feeling in the previous mountain driving condition is the same. remains, so there is a way to continue controlling it using the sensitivity characteristics that you have become accustomed to mountain driving without reducing the sensitivity and making the Nordl heavier. In that case, the configuration of the control device is such that after controlling the auxiliary force based on the predetermined value of the increased sensitivity of the sensitivity characteristic modulating section, the auxiliary force is controlled based on the sensitivity output from the sensitivity characteristic basic section. a counter that counts the elapsed period from the time of starting; and when the next mountain driving state is reached before the counted value of the counter reaches a predetermined value, the increased sensitivity is calculated from the beginning of the mountain driving introduction section; and a continuation control section for controlling the auxiliary force based on the predetermined value of .

[Operation] FIG. 2 is a characteristic diagram for explaining the operation of this device. The horizontal axis is the distance traveled. Figure (a) is a characteristic diagram showing the change in steering angle dispersion with respect to travel distance, Figures (b) and (c) are characteristic diagrams showing typical control characteristics of sensitivity, which is a feature of the device of the present invention. be. The mountain driving determination unit 6 determines the range where the steering angle variance M is greater than or equal to M2 to be a mountain driving state. When the minute 11k is less than M2, it is in city driving condition, and in mountain driving condition L1~
The L2 section is a mountain driving introduction section that provides a guide for getting used to mountain driving. In the introduction sections of city driving and mountain driving, the auxiliary force is controlled based on the sensitivity characteristics output from the sensitivity characteristics basic section 5. The sensitivity characteristic bar 5 changes the sensitivity characteristic according to the dispersion state M detected by the dispersion state detection section 3. Therefore, as the vehicle changes from city driving to mountain driving, the sensitivity G is controlled to decrease from G1 to G3 as shown in FIGS. (a) and (b), and the steering wheel becomes heavier. The sensitivity characteristic modulation unit 7 is configured to adjust the mountain driving state (Ll to I,
3) If the steering wheel is heavily controlled and you are still driving in the mountains after a predetermined period of time (traveling distance L1 to L2, traveling time, etc.) has passed, the sensitivity G is gradually increased from the current sensitivity G3 to a predetermined value. G2 (value smaller than sensitivity G1 when traveling in a straight line)
Change it so that it becomes larger. As a result, when the driver gets used to mountain driving, the steering wheel becomes lighter and the driver can continue mountain driving with ease. In addition, when the sensitivity output from the sensitivity characteristic basic unit 5 becomes larger than the sensitivity G2 when getting used to mountain driving, after L4 (Figure B) and L5 (Figure C), it is assumed that the state of mountain driving has been escaped, and the steering angle is changed. Sensitivity G is determined depending on the dispersion state. Due to this effect, when the driver becomes accustomed to mountain driving, the sensitivity can be increased and the steering wheel operation can be made lighter in subsequent mountain driving. [Embodiment] The present embodiment relates to a hydraulic power steering device. In this embodiment, the sensitivity characteristics related to the vehicle speed and the sensitivity characteristics related to the steering angle are changed depending on the dispersion state of the steering angle. In other words, the higher the vehicle speed, the more
With respect to the steering angle, sensitivity characteristics are changed depending on the molecule t&state so that the larger the steering angle is, the lower the sensitivity is, the smaller the auxiliary steering force generated in response to the manual torque, and the heavier the steering feel. Embodiments of the present invention will be described below based on the drawings. In FIG. 3, reference numeral 10 denotes an auxiliary force generating means, which includes a servo valve 14, a power cylinder 15, a solenoid valve 20, a solenoid drive circuit 65 for driving the solenoid valve 20, and a pump 22.
, a flow rate control valve device 40 , a solenoid drive circuit 75 for driving the same, and a hydraulic circuit 12 . The servo valve 14 is connected to the steering wheel 19 via a handle shaft 17, and the power cylinder 15 is connected to the steering wheel via a steering linkage of the circuit. Therefore, by applying manual torque to the steering handle 19 and controlling the rotation of the servo valve 14, the supply of pressure fluid to the power cylinder 15 is controlled, and the power cylinder 15 generates and increases the auxiliary steering force. The steering torque (manual torque + auxiliary steering force) is transmitted to the steered wheels. A pump 22 is connected to the servo valve 14 via a hydraulic circuit 12.
is connected. This pump 22 is connected to an automatic engine via a belt drive system, and the pumping action of this pump 22 supplies pressurized fluid to the servo valve 14 and power cylinder 15. Also, a solenoid valve 20 is attached to the power cylinder 15.
I'm being kicked. This solenoid valve 20 bypasses a part of the pressure fluid supplied to one high pressure chamber of the power cylinder 15 to the other low pressure chamber of the power cylinder 15, and its structure is shown in the fourth sectional view. There is. The solenoid valve 20 is
A valve body 24, a spool 26 slidably inserted into an inner hole 25 of the valve body 24, and a solenoid 27.
It is equipped with The spool 26 is normally held at the lower end by the bias of the spring 28, and the passage 30 communicating with the left chamber of the power cylinder 15 and the passage 31 communicating with the right chamber are blocked from communicating with each other. When an attractive force is applied to the spool 26 according to the current value applied to the solenoid 27, the spool 26 is displaced upward against the spring 28, and the passage 30
．． 31 are communicated with each other via a bypass slit 34. The pump 22 is further provided with a flow rate control valve device 40 that controls the discharge flow rate. This flow control valve device 40
As shown in FIG. 5, there is a throttle 45 that controls the pressure fluid flowing from the discharge hole 42 of the pump 22 to the delivery port 43, and the fluid is slid by the back and forth pressure of the throttle 45 to open and close the bypass hole 44 and flow to the servo valve 14. It consists of a spool valve member 4 ( ) that controls the supply flow rate of the pressure fluid to be supplied, and an electromagnetic valve 48 that is attached coaxially with the spool valve member 46 and that adjusts the opening degree of the throttle 45 . The solenoid valve 48 includes a solenoid 49, a movable spool 50 that is displaced by energization of the solenoid 49, and a valve shaft 51 integrally connected to the movable spool 50. The movable spool 50 is normally moved together with the valve shaft 51 by a spring 53, and the orifice 45
The throttle 45 is pressed to the opposite side, and the throttle 45 is fully opened. However, as the movable spool 50 is displaced in the direction of the throttle 45 against the repulsive force of the spring 53, the valve shaft 51 moves toward the throttle 45.
5 and decrease its opening. This operation causes the servo valve 14 to be removed from the delivery port 43.
The supply flow rate of pressure fluid to is reduced. In FIG. 3, 60 is an electronic control device. This electronic control device 60 includes a microprocessor 61, RΔM62, and ROM63.
is the main component. This microprocessor 6
1 is connected to an interface 64, and the interface 64 is connected to solenoid drive circuits 65 and 75. The solenoid drive circuits 65 and 75 control the current applied to the solenoid 27 of the electromagnetic valve 20 and the solenoid 49 of the flow control valve device 40, respectively. Further, a steering angle sensor 69 is connected to the microprocessor 61 via an interface 66, a counter 67, and a phase determination circuit 68. This steering angle sensor 69 consists of a rotating plate 70 connected to the steering shaft 17 and two photo-in club toughs 1.72, and detects the steering angle θ of the steering wheel from the signal from the photo-in club toughs 1.72. It is supposed to be done. Furthermore, microprocessor 6
1 is connected to a vehicle speed sensor 74 via an interface 66 and a counter 75. The vehicle speed sensor 74 is composed of a tachometer connected to the output shaft of the transmission, and the vehicle speed is determined from the frequency of the pulse signal generated from the vehicle speed sensor 74.
is being detected. On the other hand, the control pattern of the applied current applied to the solenoids 27 and 49 of the electromagnetic valves 20 and 48 is stored in the R'0M 63 as a characteristic map. This control pattern is 9jI as shown in FIG.
A control pattern for city driving consisting of a combination of characteristic map ■Δ and T B and a characteristic map T as shown in FIG.
A control pattern ■ for mountain driving consisting of a combination of T△ and n13 is prepared, and the respective characteristic maps ■Δ and ■Δ are used to drive the solenoid 49 of the electromagnetic valve device 40 that controls the flow rate supplied to the servo valve 14. used. Further, the characteristic map IB, n13 is used for driving the solenoid l-' 27 of the electromagnetic valve 20 that bypass-controls both end chambers of the power cylinder 15. The characteristic is that in control pattern I, as the vehicle speed increases, the current value IB applied to the solenoid l-' 27 is increased, the bypass flow rate of the power cylinder 15 is increased, and the steering wheel is set heavier as the vehicle speed increases. Further, as the steering angle θ increases, the current iIΔ applied to the solenoid I-' 49 is increased, and the amount of pressure fluid supplied to the servo valve 14 is decreased, so that the steering wheel becomes heavier as the steering angle increases. These characteristics control the sensitivity of city driving when the steering angle dispersion is at its minimum. On the other hand, in control pattern (2), the degree of change in the current B TΔ that should be applied to the solenoid 49 with respect to an increase in steering angle θ is set to be larger than in control pattern (2). These characteristics control the sensitivity of mountain driving when the steering angle dispersion is at its maximum. That is, when driving in the mountains, the larger the steering angle, the heavier the steering wheel operation becomes compared to when driving in the city. The RAM 62 stores a program for sequentially storing the steering angle θ of the steering wheel, detecting the dispersed state of the steering angle, and a program for determining whether the vehicle is in a mountain driving state from the dispersed state. Figures 8 and 9 show the dispersion of the steering angle θ. In city driving, the number of steering operations is high near neutral, and the variance shown in Figure 8 is shown, and in mountain driving, the steering angle is near neutral. The number of times the steering wheel goes out of alignment and turns the steering wheel significantly increases, resulting in a dispersion as shown in Figure 9. Therefore, by executing the above program, the state of dispersion of the steering angle θ can be detected, and the intermediate characteristics of control patterns I and IT shown in FIGS. 11 and 12 are selected according to the dispersion state. be able to. Next, the operation of the distributed state detection section will be explained based on the flowchart 1- shown in FIG. The ever-changing steering angle signal θ detected by the steering angle sensor 69 while the car is running is input to the counter 67 via the phase determination circuit 68, and is also input to the vehicle speed sensor 74.
The vehicle speed signal ■ detected at is also input to the counter 75. On the other hand, the microprocessor 61 executes processing operations based on the program at the same time as the interrupt signal is input. First, in step 100, the steering angle θ and vehicle speed ■ stored in the counters 67 and 75 are read and stored in an internal register. Subsequently, in step 101, the content 1 of the sampling number counter C is compared with the set number n. At the start of operation, no sampling is performed and the content i is O, step 102 is executed and 1 is added to the content i of the number counter C. In the following step 103, the sum S of the steering angle θ is calculated based on the formula below.
A sum of squares SQ of UM and the steering angle θ is calculated. SUM=SUM ten θ −−−−1−(1)
SQ=SQ+θ2-- (2) Subsequently, in step 105, the variance S is calculated from the above SUM and SQ using the following equation. 5=SQ/i −(SUM/i)” ~・
(3) Next, in step 106, the above-mentioned variance S is stored as an index M indicating the degree of frequency of bends in the running road. Below this M
is simply called the actual variance. Next, in step 107, a sensitivity control program is executed to control the optimum sensitivity from the actually measured variance M. From then on, every time an interrupt signal is output, the microprocessor 6
1 repeatedly executes steps 100 to 106 in the same way as above, and sets the weight of the steering wheel according to the running condition. However, while the above processing operation is being executed, the contents of the steering angle θ are gradually accumulated, and the value of the variance S becomes too large, making it impossible to make a correct determination. Therefore, after sampling has been performed n times, in step 104, the sum SUM of the steering angles θ and the sum of squares SQ of the steering angles θ are corrected based on the following formula. SUM=SUM+θ-3U M/n--゛(4)S
Q=SQ+θ2− S Q / n ---(5)
” The two equations add new values θ, θ to the previous values SUM, SQ.
2 is added, and at the same time, the average values SUM/n and SQ/n of the respective values up to now are subtracted as old data. Through such processing, after n times of sampling, part of the data of the old steering angles θ and θ2 is successively replaced with new data, and an accurate variance S can be obtained. After the above arithmetic processing, steps 105 to 107 are executed as in the case of sampling less than once, and steering force control is performed according to the driving state. Figure 7 is a flowchart 1 to 1 showing the sensitivity control program.
It is. FIG. 10 is an explanatory diagram for explaining the operation of the device. The actually measured dispersion M changes as shown in FIG. 10(a) depending on whether the vehicle is traveling in a city or in a mountain. Mt is a constant that distinguishes between mountain driving and city driving. That is,
When the actually measured dispersion M becomes equal to or greater than Mt, it is determined that the vehicle is in a mountain driving state. In step 202, the value of C is set to 0. C is a counter for counting a certain amount of time. As will be described later, if there is a short city trip between two mountain trips, the steering feel from the previous mountain trip will not be lost even if there is a short city trip. Therefore, even if the vehicle travels in the mountains again next time, it is better to not make the steering feel heavy so that a better steering feeling can be obtained. C counts the period during which the sensation of this previous mountain run is not lost. Next, in step 204, it is determined whether the value of MC has reached ML. MC is a dispersion that is artificially generated to lightly control the steering force when the driver gets used to mountain driving, and is hereinafter referred to as control dispersion. The control variance MC gradually decreases from the maximum value Mm to the minimum value M L "I. In step 206, the value of MC is reduced to the minimum value ML.
It decreases by 1 until it reaches . In step 208, the magnitude of the control dispersion MC and the currently measured dispersion M is compared, and if the currently measured dispersion M is less than the control dispersion MC, the process proceeds to step 210, and the control dispersion MC of the solenoid 49 of the solenoid valve 48 is The dispersion Ma for determining the drive current IA is the actual dispersion M
Set to . Hereinafter, the dispersion Ma used to determine this drive current will be referred to as effective dispersion. Next, in steps 214 and 216, as shown in FIGS. 11(a) and 12(a), the characteristic diagram of the drive current IAa with respect to the steering angle in urban driving with a minimum variance of 0 and the maximum numerator t(t
Drive current I with respect to steering angle in mountain driving of M p
Each drive current corresponding to the steering angle is searched from the characteristic diagram of Δb. Next, in step 218, the drive current IA is calculated by interpolation using one-case distribution according to the execution variance Ma. That is, when the measured dispersion M is smaller than the control dispersion MC (LO~I
-3), the auxiliary force is controlled according to the actually measured dispersion M. A schematic diagram of the process of calculating the drive current by interpolation is shown in the 13th
It is shown schematically in the figure. Figure 13 (a) shows the relationship between the steering angle and drive current IAa when driving in the city when the actually measured variance M is 0, and Figure 13 (b) shows the steering angle when driving in the mountains when the actually measured variance M is the maximum Mp. This figure shows the relationship between the drive current ■Δb and the drive current ■Δb. Then, in the intermediate dispersion state, the drive current is determined by interpolating these two characteristics. The intermediate current value I determined in step 220
A control signal for controlling A as the drive current of the solenoid 49 is output to the solenoid drive circuit 75. Next, the process proceeds to step 222, and the 11th
The drive current IBa for city driving and the drive current IBb for mountain driving are read out from the characteristic diagrams shown in FIG. 12(b) and FIG. drive current IB
seek. Next, in step 228, a control signal for controlling the determined intermediate current value IB as the drive current of the solenoid 27 is output to the solenoid drive circuit 65. In this way, control of the auxiliary force regarding the steering angle and vehicle speed is performed in accordance with the actual dispersion M. Next, in step 208, the currently measured variance M is changed to the control variance M
If it is determined that it is larger than C(L3), step 212
Then, the effective dispersion Ma is set to the control dispersion MC, and the auxiliary force is controlled according to the control dispersion MC. In other words, in steps 214 to 228, the drive current is determined by interpolation using the control distribution MC, and each solenoid 49, 27 is controlled accordingly. As a result, even if the actually measured dispersion M indicates a mountain driving condition, the control dispersion MC is attenuated after a delay of 2 to L3 after starting mountain driving, so it is controlled by the control variance MC. Operation becomes easier. When it is determined in step 208 that the current actual measurement variance M is less than or equal to the control variance MC (L5.L8), the process moves to step 210, sets the actual measurement minute: ik M to the effective variance Ma, and calculates the actual measurement variance. Control by M is performed. Next, if it is determined in step 200 that the measured variance M is smaller than the predetermined value Mt, the process moves to step 230. In steps 230.234.232, the actual measured minutes ti&M
A counter C counts the running period in which the value Mt is smaller than a predetermined value Mt, and after the predetermined period has elapsed, the value of MC is set to the maximum value Mm in step 232. Therefore, when the actually measured dispersion M changes from larger to smaller than the control dispersion MC, it is controlled by the actually measured dispersion M. Next, after a predetermined period Cm has elapsed, if the actual measured variance M becomes larger than the predetermined value Mt (LSI), the step 20 described above is performed.
2 or less are executed. At this time, the control distribution MC is already at L6
Since this is set to the maximum value Mm, the above-mentioned control is performed when mountain driving is newly started. That is, the predetermined period Cm
Since the time has passed, I have decided to perform a new control for mountain driving, assuming that the steering sensation from the previous mountain driving has disappeared. On the other hand, if the actually measured variance M becomes equal to or greater than the predetermined value Mt before the predetermined period Cm has elapsed (L9), step 20
2 or less are executed. When L9 to L11, control is performed using the actually measured dispersion M in steps 202 to 208 to 210 to 214. The control distribution MC at this time is
Since step 232 has not been executed, the predetermined value ML is maintained. Therefore, the actual dispersion M is Ml (-MC)
If it is larger (L1.1.) step 204.
208.212 are executed sequentially to obtain a predetermined value ML to which the control dispersion MC is attenuated while the actual dispersion M is larger than the predetermined value ML.
The auxiliary force will be controlled by That is, the predetermined period Cm
If you start the next mountain drive before the end of the mountain drive, it is determined that the steering feeling from the previous mountain drive remains, and the predetermined value ML is set from the beginning of the mountain drive without increasing the steering force.
(N, 11 to L20) which controls the steering wheel to make it lighter.
. Next, a second embodiment of the present invention will be explained. The program for measuring the steering angle dispersion has already been published in the 6th edition.
It is shown and explained in the figure. FIG. 14 is a flowchart 1- showing the processing procedure of the characteristic part of the apparatus according to the second embodiment. Further, FIG. 17 is an explanatory diagram for explaining the operation of the device. As shown in FIG. 16, the device of this embodiment stores the steering angle characteristics of the solenoid drive current IAs in the city driving mode in which the actually measured variance M is 0 as a map. Then, based on the characteristic IΔS, the amplification factor K for the reference current Io of the curve is changed to obtain the control characteristic ■Δm of the mountain running mode and the intermediate control characteristic IΔ. Here, K is defined by the following equation. ΔIAs=IAs−I. ΔIA-IA-IAs = ΔI
A/ΔIAs K is the control characteristic of city driving mode when K is 0, the control characteristic of mountain driving mode when K is Km, the control characteristic when getting used to mountain driving when K is Kt, respectively. It represents the amplification factor with respect to the reference current ■0. In step 300, if the actually measured dispersion M is smaller than Ml (LO to Ll), it is determined that the mode is city driving mode, the process moves to step 302, the value of K is set to 0, and step 3
04 mountain running feeling residual determination program is executed. This program will be described later. In step 306, the reference drive current IAs corresponding to the steering angle θ is searched from the map, and in step 308, the solenoid 4 for controlling the manual torque Tm according to K is searched.
A drive current IA for driving 9 is calculated. In this case K
is set to 0, so the drive current IΔ becomes IAs. In step 310, a control signal is output to the solenoid drive circuit 75 to drive the solenoid 49 so that the drive current of the solenoid becomes IA, thereby controlling the auxiliary force with respect to the steering angle. Next, in step 312, the drive current TBa of the solenoid 27 for the vehicle speed in urban driving shown in FIG. 11(b) is used as a reference current IBs to search for the corresponding drive current. Then, in step 314, a current IB is determined according to the value of K, and in step 316, a control signal corresponding to IB is output to the solenoid drive circuit 65 to drive the electromagnetic JP 20, thereby controlling the auxiliary force relative to the vehicle speed. Next, if it is determined in step 300 that the variance M is larger than Ml, the process moves to step 320, where M is compared with the upper limit Mh by LL, and if it is smaller than Mh (Ll~T-3), step 321 After that, in steps 322 and 323, the amplification factor K of the characteristic curve is calculated according to the dispersion M actually measured at that time. In other words, when M is less than the minimum value M1, the amplification factor is 0.
Therefore, when the dispersion M is greater than or equal to Mt, the amplification factor has the maximum value K
m, and when M l < MUM t, K is 0 <K'
It becomes the intermediate value of <Km. In this way, the amplification factor increases according to the actually measured dispersion M until starting mountain driving (Ll to L2), and the solenoid 49
As the drive current ■Δ increases, the auxiliary force of the handle decreases,
The handle becomes heavy. Next, in step 324, the value of K is compared with Kt once and Kt
If it is larger, the value of N is determined to be Nm in step 328. Since N is initially set to 0, steps 306 and subsequent steps are executed. In this way, when the vehicle enters mountain driving at Ll and the measured dispersion M becomes equal to or greater than Mh at point L3, this is determined in step 320, and it is determined that the driver has become accustomed to mountain driving, and the process proceeds to step 340. Step 3
40.342.344 is a processing procedure for gradually decreasing the amplification factor K from the maximum value Km to Kt. Here, after N gets accustomed to mountain driving (L3), the amplification factor K of the characteristic curve is decreased and the auxiliary steering force is increased to lighten the steering wheel operation (
L3-L4), where N varies from O to the maximum value Nm. Correspondingly, the amplification factor I changes from the maximum value Km to Kt. Through these steps, the amplification factor characteristics not shown in L3 to L5 can be changed. 1) As a result, after a certain period of time L2 to L3 after starting mountain driving, the steering wheel operation becomes gradually lighter. In addition, when the actually measured dispersion M becomes smaller than Mt, in the section where the amplification factor K determined by the actually measured dispersion M is larger than the predetermined value Kt, the amplification factor is set to the predetermined value in step 330 via steps 324 and 328. It continues to be set to Kt. On the other hand, when the amplification factor K becomes equal to or less than the predetermined value Kt (L5), steps 324, 326, and 306 are executed, and the amplification factor is controlled to the amplification factor determined in step 322 according to the actually measured dispersion M. Furthermore, the actual dispersion M is less than M1 (L6
), the amplification factor is set to O in step 302. When the amplification factor K becomes less than or equal to Kt (L5, L9), the mountain running feeling residual determination program shown in step 304 or 326 is executed. The processing procedure is shown in FIG. After mountain driving, N is set to the maximum value Nm. In steps 402 and 408, the counter C counts, and when the value reaches Cm, N and C are set to 0. Until N is set to 0, N holds the maximum value Nm, so during that time, the actual variance M is determined by the judgment in step 324 or the judgment in step 328 and the processing in step 330. The amplification factor is controlled by the smaller of the predetermined value Kt. That is, in L8,
After Cm has elapsed, the amplification factor K determined by the dispersion M is larger than Kt, so we execute steps 328 and 306 and determine that the steering feeling from the previous mountain run has disappeared, so we change the steering wheel when starting the next mountain run. The operation is set to be heavy. On the other hand, in LIO, the amplification factor K obtained from the dispersion M before the passage of Cm is larger than Kt. Therefore, at this time, it is determined that the steering feeling from the previous mountain trip remains, and steps 328 and 330.
Even if you execute 306 and enter the next mountain hiding run, the amplification factor K remains unchanged.
I try not to make it larger than t. As a result, even when driving in the mountains, the steering becomes easier to operate from the beginning. Although this embodiment describes a hydraulic power steering device, the present device can also be applied to an electric power steering device. Further, although the sensitivity is controlled using the electromagnetic valves 20 and 48, it may be controlled using only one of them.

【Effect of the invention】

In a power steering device, the present invention measures the dispersion of the steering angle, controls the sensitivity according to the measured value, and also determines the mountain driving condition.When driving in the mountains, the sensitivity is initially reduced and the steering wheel is It is made heavier and equipped with a control device that reduces the sensitivity after running for a certain period of time. Therefore, when driving around town, the sensitivity can be set to a high value, allowing for easy steering operation. Furthermore, when starting mountain driving, the sensitivity is set to a low value, so the steering wheel becomes heavier, which improves the safety of mountain driving. Furthermore, when the driver gets accustomed to mountain driving, the sensitivity is increased and the steering wheel is made lighter, which ensures safety and prevents the driver from becoming fatigued due to steering wheel operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the concept of the present invention. FIG. 2 is a characteristic diagram for explaining the operation of the device of the present invention. FIG. 3 is a block diagram showing the configuration of a device according to a specific embodiment of the present invention. FIG. 4 is a sectional view showing the configuration of a solenoid valve that bypasses the high pressure chamber and low pressure chamber of the power cylinder used in the device of the embodiment. FIG. 5 is a sectional view showing the configuration of a solenoid valve for controlling the discharge capacity of the pump used in the apparatus of the embodiment. FIG. 6 and FIG. 7 are flowcharts showing the processing procedure of the CPU used in the device of the embodiment. FIG. 8 and FIG. 9 are characteristic diagrams showing the dispersion characteristics of the steering angle measured in the processing procedure of the CPU. FIG. 10 is an explanatory diagram showing the operation of the device of the embodiment. FIG. 11 is a characteristic diagram of the drive current for controlling the solenoid 49 and the solenoid 27 with respect to the steering angle and the vehicle speed during city driving where the actual measurement variance is 0. FIG. 12 is a characteristic diagram of the drive current with respect to the steering angle and vehicle speed for controlling the solenoid 49 and the solenoid 27 τli when driving on mountainous terrain where the actually measured dispersion takes a predetermined value. FIG. 13 is an explanatory diagram showing a method of interpolating and finding the optimum steering angle characteristic according to the variance. FIGS. 14 and 15 show other embodiments of the apparatus. 14°° Servo valve 15... - Power shifter 22° Pump 27. 49 - Solenoid 40° Flow control valve device 48°° Solenoid valve 60° Electronic control device 69° Steering angle sensor 74 Vehicle speed sensor Patent applicant Toyoda Machine Tool Co., Ltd. Agent Patent Attorney Osamu Fujitani 11th 12th (IIA) (a) (b) Figure (b)

Claims (2)

[Claims] (1) An auxiliary force generating means that generates an auxiliary force that assists the steering force of the automobile in response to a control signal from a control device; a steering angle sensor that detects the steering angle of the steering wheel of the automobile; and a steering angle sensor that detects the steering angle of the steering wheel of the automobile. A distributed state detection unit that determines the distributed state of the steering angle of the steering wheel from the output signal, and a ratio of the auxiliary force to the manual torque input to the steering wheel of the automobile according to the distributed state determined by the distributed state detection unit. A power steering device comprising a control device that changes sensitivity and controls the auxiliary force output by the auxiliary force generating means according to the sensitivity, wherein the control device detects the distributed state detection section. a mountain driving determination unit that determines that the vehicle is traveling in a mountainous area based on the distributed state of the steering angle; a sensitivity characteristic basic unit that determines the sensitivity according to the dispersion state of the steering angle determined by the vehicle; , a sensitivity characteristic modulation unit that gradually increases the sensitivity from the sensitivity at the time when the mountain driving introduction section has passed, which is a predetermined period after entering the mountain driving state, to a predetermined value, and maintains the predetermined value for a predetermined period; and an auxiliary force control section that controls the auxiliary force output by the auxiliary force generating means in accordance with the sensitivity characteristic basic section and the sensitivity characteristic modulation section. removal device. (2) The control device controls the auxiliary force based on the predetermined value of the increased sensitivity of the sensitivity characteristic modulation section when the vehicle is traveling in a mountain, and then adjusts the sensitivity output from the sensitivity characteristic basic section to a counter that counts the elapsed period from the time when the assisting force was started to be controlled based on the above-mentioned information; The power steering device according to claim 1, further comprising a continuation control section that controls the auxiliary force based on the predetermined value of the increased sensitivity from the beginning of the section.