JP2907824B2 - Suspension control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to automobiles, and more particularly to the realization of motion and vibration characteristics of automobiles adapted to personal preferences or a high degree of harmony between ride comfort and operability at high speeds. The present invention relates to a suspension control method suitable for realizing the above. [Prior Art] The conventional control method is described in the automobile technology Vol. 39, No. 12, 1422-
As you can see on page 1427 (1985), whether the suspension characteristics are manually selected or left to automatic control, the resulting characteristics are those set by the manufacturer and No consideration was given to changing this setting based on preference. In the conventional control method described above, the suspension characteristics are fixed during high-speed running. Therefore, no consideration has been given to achieving a high degree of harmony between ride comfort and maneuverability, which is required when driving along a highway joint. [Problems to be Solved by the Invention] The prior art described above does not take into consideration the learning or optimization of the occupant's preference, and has a problem that the suspension characteristics do not match the occupant's preference. In the above prior art, no consideration is given to points of disturbance such as road joints. When the soft suspension (small damping force) is fixed, the vibration continues for a long time, and when the hard suspension (large damping force) is used, the vibration is long. There was a problem of receiving a large impact force. SUMMARY OF THE INVENTION It is a first object of the present invention to provide a suspension control method having a suspension characteristic suited to passenger's taste. A second object of the present invention is to provide a suspension control method that reduces impact force, accelerates vibration convergence, and achieves high harmony between ride comfort and maneuverability. [Means for Solving the Problems] To achieve the above object, the first characteristic of the present invention is:
To incorporate into the suspension control system means for inputting the evaluation of the occupant's riding comfort, drivability and drivability to the vehicle by touch panel or voice and means for changing the control gain and parameters in the suspension control logic based on the input information is there. A second feature of the present invention is to predict a time at which a wheel passes through a seam, and assume a soft suspension characteristic during the passage of the seam.
After the seam passes, the optimal time is switched to the hard or normal suspension characteristic. The optimal time is the time when the speed at which the distance between the unsprung part and the sprung part decreases at the first maximum value after passing the seam when the seam is convex, and when the seam is concave, Later, the time at which the speed at which the distance between the unsprung and sprung distances decreases takes a second maximum value. However, the above criterion of optimality is a case where emphasis is placed on the RMS value (root mean square) of the acceleration on the spring and the convergence speed, and the optimal time is as follows in consideration of the smoothness of the acceleration change as a criterion. . When the seam is convex and concave, this is the time when the relative speed between the unsprung part and the sprung part immediately before the optimal time becomes zero. [Operation] According to the first feature, the vehicle can obtain information for determining the occupant's individual preference by means of inputting the evaluation of the occupant to the vehicle by touch panel or voice. Further, based on the above information, the control logic reflecting the occupant's preference is learned by means of changing the control gain parameter in the suspension control logic. The second feature is that the soft suspension is used during the passage of the seam to minimize the impact force applied to the vehicle body, and after passing the seam, the vibration is converged by switching to a hard or normal suspension at an optimal time. Be faster. Embodiment An embodiment of the present invention will be described below with reference to FIG. The occupant 2 of the vehicle 1 presses the "soft" key on the touch panel 3 when it is desired to delay the suspension or the yaw response on the spring to the steering of the steering wheel in each running state. If the user wants to make the sprung yaw response to the hard suspension or the steering of the steering wheel faster, the "hard" key is pressed. The microcomputer 6 performs information processing based on the digital data 12 from the touch panel 3 and the motion state data 13 output from the motion state measurement sensor 4 of the automobile, and issues a suspension state operation command 14 to the actuator 5 of the suspension. Hereinafter, data processing performed by the microcomputer 6 will be described in detail. FIG. 2 shows a flowchart of the soft processing. The micro computer 6 repeats the processing of FIG. 2 every 0.1 seconds. In the target suspension state calculation step 25, the relationship _ai = f (running state, running state classification parameter) is established corresponding to the actuator 5 which can take the suspension state of n stages (a ₁ ,..., _An ). Based on this, a target suspension state is calculated. Here, the vehicle speed, the front and rear of the car, lateral, vertical acceleration, steering wheel Misaohebi angular velocity, a ₁ than the running state space Surotsutoruwaiya movement speed, ... mapping function into the space formed of n values of a _n is f. As shown in 3-5 Figure, divides the traveling state space by the traveling state classification parameters _{(v 1, v 2, v} 3, v 4, w 1, w 2, α 1 .α 2 , etc.), f ^-1 (A _i ), i = 1,... N, and this parameter characterizes the function f. In the parameter change processing step 24 in the target suspension state calculation algorithm, the value of the traveling state classification parameter is changed or the value a _i of the mapping destination is changed as follows. Here, a _1, ... in the order of a _n, spring constant, attenuation coefficient shall change to a hard-suspension Chillon to increase. The current driving state is represented by x, and when the current f is used, _ai is selected. (1) When the "soft" key is pressed, among the parameters for dividing the driving state space to which x belongs, , F ^-1 (a _i-1 ), the parameter p defining the boundary with the space
_With respect to ₁ ,..., P _m , the space of f ⁻¹ (a _i ) is reduced by changing p _i → p _i + Δp _i , i = 1,. Or,
Dividing the running state space, A _1, ..., with respect to A _l, if x∈A _i, changes the f f (x, running state classification parameter) = a _i-1 and. (2) When the “hard” key is pressed, a parameter p defining a boundary with the space of f ⁻¹ (a _{i + 1} ) among the parameters for dividing the running state space to which x belongs.
_{For 1} , _{1 k} , the space of f ⁻¹ (a _i ) is reduced by changing p _i → p _i −Δp _i , i = 1,..., K. Alternatively, if X∈A _i, a f f (x, running state classification parameter) = change with a _{i + 1.} In the measurement data reading / data processing step 21, the data of the vehicle speed of 10 samplings measured every 0.01 seconds, the front and rear, left and right, up and down acceleration, steering wheel steering angular speed, and throttle wire moving speed are read every 0.1 seconds. The best value of each of these values for the past two seconds is passed as the traveling situation as data used in the following processing. The data defining this f-function is a magnetic card or
It can be removed with an IC card. Therefore, the crew
By inserting your own card, you can enjoy ride comfort and maneuverability that suits your tastes. FIG. 6 shows another embodiment of the present invention. In the figure, an automobile 31 has a two-stage switching function between a hard suspension and a soft suspension. The information of the vehicle speed measurement value 41 which is the output of the vehicle speed sensor 32 and the measurement value 42 of the damper stroke position which is the output of the damper stroke sensor 33 is transmitted to the microcomputer 34 every 0.01 second.
, Processes these data, and sends a suspension switching command 43 to the suspension actuator 35.
Put out. The actuator 35 switches the suspension characteristics according to this command. Here, the switching time is the same for all four wheels. The block diagram in the micro computer 35 shows the concept of information processing. Hereinafter, data processing performed by the microcomputer 35 which is a main part of the present invention will be described in detail. FIG. 7 shows a flowchart of the soft processing. The micro computer 35 repeats the process of FIG. 7 every 0.01 seconds. In the decision step 64 of the switching time to the software, the response speed of the actuator is considered to be 0.1 second, and the front wheel is shifted from the joint by 0.11 second.
^f (m) approximately whether in front _{^{x f = d-x 0 -x}} x: travel distance after the front wheel seam passing through (m) x ₀ = v (speed m / sec) × 0.11 d: between seams distance determined by the estimate of, x ^f <0 if YES, if otherwise, determines that the NO. In front seam passage judgment Sutetsu 66, the front wheel past n times of the mean current measurement value y _f from _f measurements 42 of the damper-stroke position is | y _f - _f | when s _f in (threshold), the seam Is determined to have passed. However, once it is determined that the vehicle has passed, even if the above inequality holds, it is not determined that the vehicle has passed the seam for 0.2 seconds. If it is determined that the pass, as ^{r = x f x = v ×} 0.01, determine the estimation error r of the seam between the distance (m), set the x. In estimating step 55 of the seam between the distance estimate d ₁ of the distance between the past n times of the seam, ... d _n and the estimated error r _1, from ... r _n, To find a new estimate. Α _i in the above equation is a weight coefficient. In the seam passage determination step 67 of the rear wheel, the rear wheel portion past n times of the average value _f and the present measured value y _f of the measured value 42 of the damper-stroke position is | y _r - _r | s _r of (threshold) At this time, it is determined that the joint has passed. However, once it is determined that the vehicle has passed, even if the above inequality holds for 0.2 seconds, it is not determined that the vehicle has passed the seam. In the step 68 for determining the re-estimation of the seam distance, the running distance x ₁ (m) after the time of switching to the software is obtained from the vehicle speed data, and if x ₁ −x ₀ −l0.5 l: wheel base (m) YES, otherwise NO. In the step 56 for estimating the distance between the joints, the estimation error q (m) of the distance between the joints is obtained as q = x ₁ −l ₁ −x ₀ , and d = d + q is set as a new estimated value. In decision seam concave or convex step 57, y _r - _r s _r if convex y _r - determines that _r -s _r if concave. This is because the automobile has characteristics as shown in FIGS. 8 and 9. The calculation unit 22 of the switching time of the soft → hard to determine the t ₂ of t ₄ and FIG. 11 of FIG. 10 is optimal switching time corresponding to the unevenness of the seam as follows. (If convex) The damper stroke speed _yr is calculated from the data of the measured value 12 of the damper stroke position. (Rear-wheel joint passage time plus unsprung natural vibration period t ₀ seconds (typically 50-100m
When the y _r after the 1/4 time of) of sec) series data y _r (t)
At (t: time), for the first time, y _r (t) <y _r (t + 0.0
1) is obtained, and y _r (t−0.01), y _r (t), y _r (t +
0.01), t ₁ in FIG. Ask for. The optimal switching time t ₂ in FIG. 10 is obtained by adding the unsprung natural vibration period t ₀ to t ₁ , Ask for. In (in the case of a concave) time-series data y _r of y _t after the (rear wheel seam passing time _{+ t 0/4) (t} ), for the first time, y _r (t)> y
_r (t + 0.01) is determined, and t ₂ in FIG. Ask for. Time t ₄ instead of optimum cut is obtained by _{t 4 = t 3 + t 0} . In the hardware switching time determination step 35, if the current time t is t ゜ +0.005> tt ゜ −0.005 with respect to the obtained optimum switching time t ゜ (= t ₂ ort ₄ ), it is determined as YES. Otherwise, it is determined as NO. In the above embodiment, since the road height measurement sensor is not used, the cost is low. In the above embodiment, if a road height sensor can be further used, the switching from hardware to software can be accurately performed 0.1 seconds before passing the front wheel joint, so that the riding comfort can be further improved. The above control method is based on an evaluation criterion emphasizing the RMS value of the sprung acceleration and the convergence speed.For those who also want to consider the smoothness of the acceleration change, the optimal switching time is the T ₅ and t ₆ in FIGS. 10 and 11, and
Same as above The switching control is performed based on. [Effects of the Invention] According to the present invention, suspension control is performed in accordance with occupant's preference, so that satisfaction with ride comfort and operability is enhanced. Further, since the setting of the control gain and the parameters in the logic of the suspension control is performed in a learning manner, there is an effect that the parameter setting cost at the time of designing and manufacturing the suspension control system can be reduced. Furthermore, according to the present invention, the impact force received by the vehicle body from the road surface joint at the time of high-speed running can be minimized, and the subsequent vehicle body vibration can be suppressed at an early stage, so that there is an effect of improving ride comfort and maneuverability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a flowchart of processing performed by a microcomputer in FIG. 1, and FIGS. 3 to 5 are operations in FIG. Characteristic diagram for explaining the
FIG. 6 is a block diagram of another embodiment of the present invention, FIG. 7 is a processing flow diagram performed by the microcomputer of FIG. 6, and FIG.
Fig. 9 and Fig. 9 are diagrams showing change curves of the damper stroke position when passing the concave and convex seams, and Figs. 10 and 11 are diagrams showing change curves of the damper stroke speed when passing the concave and convex seams. 1,31 ... car, 2 ... crew, 3 ... touch panel, 4,
33 …… Measurement sensor, 5,35 …… Actuator, 6,34 ……
Microcomputer.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-244614 (JP, A) JP-A-56-31861 (JP, A) JP-A-63-151509 (JP, A) JP-A-59-1984 110932 (JP, A) JP-A-62-74703 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60G 17/00

Claims (1)

(57) [Claims] In a suspension control method for controlling a suspension characteristic of a vehicle, a time at which the vehicle passes a seam of a road on which the vehicle travels is determined by using a temporal change of a vehicle speed of the vehicle and a position of a damper stroke of the suspension. At the predicted time, the suspension characteristic is set to a soft suspension having a smaller damping force than before the time, and after the time, the suspension characteristic is set at a predetermined time according to the shape of the seam. A suspension control method comprising setting a hard suspension having a larger damping force than a suspension. 2. 2. The suspension control method according to claim 1, wherein at the predetermined time, when the shape of the seam is convex, a distance between an uppermost position and a lowermost position of the damper stroke is reduced after passing through the seam. 3. A suspension control method characterized in that a time at which the running speed takes a first maximum value is set. 3. 3. The suspension control method according to claim 1, wherein at the predetermined time, when the shape of the joint is concave, a distance between an uppermost position and a lowermost position of the damper stroke after passing the joint. A time when the speed at which the pressure decreases becomes a second maximum value. 4. 2. The suspension control method according to claim 1, wherein at the predetermined time, when the shape of the seam is convex, a distance between an uppermost position and a lowermost position of the damper stroke is reduced after passing through the seam. 3. A suspension control method, characterized in that the reduction speed is a time immediately before the time when the speed at which the vehicle takes the first maximum value becomes zero. 5. 3. The suspension control method according to claim 1, wherein at the predetermined time, when the shape of the joint is concave, a distance between an uppermost position and a lowermost position of the damper stroke after passing the joint. A suspension control method, characterized in that the reduction speed is a time immediately before the time when the reduction speed takes the second maximum value is a time when the reduction speed becomes zero. 6. The suspension control method according to any one of claims 2 to 5, wherein the shape of the joint is determined using a temporal change in a position of the damper stroke. 7. 7. The suspension control method according to claim 6, wherein the shape of the joint is obtained by comparing a difference between an already measured average value of the damper stroke position and a value of the current damper stroke position with a predetermined threshold value. 8. A suspension control method characterized by making a determination according to: