JP2006131052A - Regulating method for vehicle behavior controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regulating method for a vehicle behavior controlling device which enables a control parameter being adjusted to differences in movement performances for each vehicle to be set. <P>SOLUTION: A normal circle turning traveling is performed at the time of the shipment from a factory or the like (a step S25), and vehicle characteristics at that time are measured (a step S26). A stability factor Kh which is the control parameter is calculated from the vehicle characteristics (a step S29), and is compared with a stability factor Kh being stored in a map storage section 43 (a step S30). When required, the stored stability factor Kh is replaced (a step S31). Thus, the control parameter corresponding to the vehicle characteristics can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for adjusting a vehicle behavior control device, and more particularly to a method for adjusting control parameters of a vehicle behavior control device at the time of shipment or inspection.

Various vehicle behavior control devices are known for stably controlling the behavior of a vehicle when starting, braking, turning, and the like. For example, the technique of Patent Document 1 discloses a vehicular yaw rate control device that controls the yaw rate of a vehicle so as to coincide with a target yaw rate obtained in advance in order to increase the running stability of the vehicle. In this device, the target yaw rate is calculated based on the steering angle δ, the vehicle speed V, the left / right acceleration _Gy, and the preset stability factor, wheelbase, and steering gear ratio, and the target yaw rate is set to the target yaw rate upper limit. By limiting so as not to reach the value, control is performed so that the running stability of the vehicle is not significantly impaired.
JP 2002-219958 A

  The stability factor used for calculating the target yaw rate in the control of Patent Document 1 is a vehicle-specific function value that depends on the vehicle speed. Such other vehicle-specific constants, functions, and the like are also used as control parameters in other vehicle behavior control apparatuses.

  These control parameters are set to the same control parameter values for the same vehicle type based on characteristics of a model vehicle such as a prototype vehicle. However, in actual manufactured vehicles, there are differences in alignment due to differences in the dimensions of parts and assembly conditions, etc., and due to differences from model vehicles such as mass balance and tire performance, the vehicle's motion performance is It is not the same and deviation occurs. Therefore, when a mass-produced vehicle is controlled with control parameters that match the model vehicle, there may be a deviation in control results due to differences in motion performance.

  Therefore, an object of the present invention is to provide a method for adjusting a vehicle behavior control device that can set a control parameter in accordance with a difference in motion performance for each vehicle.

  In order to solve the above problems, a vehicle behavior control device according to the present invention is a method for adjusting a vehicle behavior control device at the time of vehicle inspection and adjustment. A step of obtaining a value, and a step of setting a reference value for control of the vehicle behavior control device based on the obtained characteristic value.

  By traveling with a predetermined steering pattern at a constant vehicle speed for each vehicle, a characteristic value related to the motion performance of the vehicle is obtained, and a control parameter serving as a control reference value is obtained and adjusted based on the obtained characteristic value. As a result, control suitable for the motion performance of each vehicle is performed, so that control characteristics closer to the characteristics obtained with the model vehicle can be obtained.

  The reference value for this control is a stability factor, the predetermined steering pattern is a constant steering angle, and the vehicle characteristic values to be obtained are preferably lateral acceleration and yaw rate. In other words, the vehicle-specific stability factor is determined based on the yaw rate and lateral acceleration during steady circular turning.

  Since this stability factor can change depending on the vehicle speed, it is preferable to obtain the stability factor corresponding to each vehicle speed by varying this constant vehicle speed.

  Alternatively, the reference value of this control is the assist ratio of the assist steering torque to the steering torque, and the predetermined steering pattern is a steering pattern having a predetermined steering angle with an amplitude at a constant cycle, and the characteristic value of the vehicle to be obtained is The slip angle is preferred. The vehicle travels while the amount of change in the steering angle over time is periodically changed to, for example, a sine curve or a sawtooth waveform. The slip angle at this time is obtained from, for example, the vehicle speed, the yaw rate, and the lateral acceleration, and assist steering characteristics such as a gear ratio and an assist torque ratio are changed.

  The assist angle may be set by obtaining the slip angle for a plurality of steering patterns having different steering angles as the amplitude. In order to accurately grasp the steering angle-slip angle characteristic, it is preferable to obtain the slip angle characteristic for a plurality of steering angles.

  According to the present invention, since the control parameter is adjusted for each vehicle based on the traveling result, the control can be performed with high accuracy regardless of the individual difference of the vehicle, and the stability and controllability are improved. This adjustment may be performed, for example, at the time of shipment or vehicle inspection. Moreover, you may perform at the time of tire replacement | exchange, various parts replacement | exchange, and adjustment.

  By adjusting the stability factor in this way, stable control during turning can be performed.

  Further, by adjusting the assist steering characteristic in this way, the controllability of steering during the operation of the power steering apparatus is improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a schematic configuration diagram of a vehicle including a vehicle behavior control device that is a target of a vehicle behavior control device adjustment method according to the present invention, and FIG. 2 is a block configuration diagram of a control portion of the vehicle. This vehicle includes an automatic steering (including a power steering function) device and a VSC (Vehicle Stability Control) system as a vehicle behavior control device.

This vehicle has a configuration capable of independently adjusting the braking force applied by the brake devices 3 _{FL to} 3 _RR disposed in each of the four wheels 10 _FL to 10 _RR . In addition to the brake devices 3 _{FL to} 3 _RR , wheel speed sensors 12 _{FL to} 12 _RR for detecting the wheel speed are arranged on the wheels 10 _FL to 10 _RR .

The front wheels 10 _FL and 10 _FR are steered wheels and are connected to a steering system. The steering system is disposed in the vehicle interior so as to be rotatable about its rotation axis, receives a steering input from a driver, a steering shaft 21 connected to the steering wheel 21 and transmits the rotational force, and the steering shaft 21. A steering gear box 22 that is a rack-and-pinion type gear mechanism that converts the rotation of the wheel to a linear motion, a relay rod 23 that transmits the converted linear motion to the front wheels 10 _FL and 10 _FR , and tie rods 24L and 24R. The steering shaft 21 is provided with a steering angle sensor 26 that detects the steering angle δ by the driver, a steering torque sensor 25 that detects the steering torque T, and a steering motor 27 that electrically applies the steering torque. . If an assist steering torque is applied according to the steering torque when the driver is steering, it functions as a power steering device. Moreover, it can be made to function also as an automatic steering apparatus which steers automatically so that the traveling lane identified by the traveling lane identification apparatus which is not illustrated may be maintained.

The brake devices 3 _{FL to} 3 _RR arranged in each of the four wheels 10 _FL to 10 _RR are, for example, hydraulic brake devices, and wheel cylinders 31 _{FL to} 31 _RR are arranged in each of them and connected to the brake actuator 30. The braking force distribution is controlled by controlling the additional oil pressure to each.

An ECU (Electric Control Unit) 4 that is a control device includes a CPU 40, a RAM 41, a ROM 42, and the like, and includes a map storage unit 43 that includes a nonvolatile rewritable memory and the like. In addition to the wheel speed sensors 12 _{FL to} 12 _RR , the steering torque sensor 25, the steering angle sensor 26, outputs from the yaw rate sensor 51 and the lateral G sensor 52 are input to the ECU 4, in addition to the steering motor 27 and the brake actuator 30. The drive system 6 including the engine is controlled. This drive system 6 control may be performed directly by the ECU 4 or may be performed by issuing a control command to a control device dedicated to the drive system 6.

  Before describing the adjustment method according to the present invention, vehicle behavior control in this vehicle will be briefly described. First, VSC control will be described. FIG. 3 is a flowchart showing an example of control processing of this VSC control. This control is repeatedly executed by the ECU 4 at a predetermined timing while the engine of the vehicle is operating.

First, read the wheel speeds which is the output of the wheel speed sensors ₁₂ FL _{to 12 RR,} which is the output steering angle δ of the steering angle sensor 26, the actual yaw rate gamma _a, which is the output of the yaw rate sensor 51 (step S1). Estimating the vehicle speed V from the wheel speed (step S2), the vehicle speed V and the steering angle [delta], based on the stability factor Kh, it obtains a target yaw rate gamma _t (step S3). The target yaw rate can be calculated by the following formula.

ここで、Ｌはホイールベース長、ｎは、ステアリングギヤボックスのギヤ比である。次に、実ヨーレートγ_ａと目標ヨーレートγ_ｔの偏差の絶対値をしきい値Δγthと比較する（ステップＳ４）。偏差がしきい値Δγth以内（未満としてもよい。）の場合には、車両挙動は安定していると判断し、安定化制御を行わないまま処理を終了する。この場合には、運転者の操作量に応じた操舵量、制動力、駆動力制御が実行される。

Here, L is the wheel base length, and n is the gear ratio of the steering gear box. Next, the absolute value of the deviation of the actual yaw rate gamma _a and the target yaw rate gamma _t is compared with a threshold Derutaganmath (step S4). If the deviation is within the threshold value Δγth (may be less), it is determined that the vehicle behavior is stable, and the process is terminated without performing the stabilization control. In this case, the steering amount, the braking force, and the driving force control corresponding to the operation amount of the driver are executed.

  On the other hand, if the deviation exceeds the threshold value Δγth (if the previous determination is less than the threshold value Δγth, if the deviation is equal to or greater than the threshold value Δγth), the stabilization control is executed (step S5). . Specifically, when the turning amount is insufficient, the brake actuator 30 is controlled to increase the brake hydraulic pressure applied to the wheel cylinder 31 of the rear wheel on the inside of the turn to increase the applied braking force and necessary. Then, the drive system 6 is instructed to reduce the engine output, and the car is turned inward. When the vehicle tends to spin, the brake actuator 30 is controlled to increase the brake hydraulic pressure applied to the wheel cylinder 31 of the front wheel on the outside of the turn, and the applied braking force is increased to suppress the spin amount. This stabilizes the vehicle behavior when turning.

  Next, the control operation of the power steering device will be described. FIG. 4 is a flowchart of this control process. This control is also repeatedly executed by the ECU 4 at a predetermined timing while the vehicle engine is operating.

First, each wheel speed that is the output of the wheel speed sensors 12 _{FL to} 12 _RR and the steering torque T that is the output of the steering torque sensor 25 are read (step S11). Estimating the vehicle speed V from the wheel speed (step S12), the based on the vehicle speed V and the steering torque T calculated to determine the assist steering torque T _a which imparts according to a predetermined map (step S13), and the assist steering torque T _a is obtained to terminate the control and processing steering motor 27 (step S14). Here, the assist steering torque _Ta is set to be larger as the steering torque _Ta is larger, larger as the vehicle speed V is lower, and smaller (may be 0) when the vehicle speed V is sufficiently fast. The steering torque for the driver to operate the steering wheel 20 is reduced by the assist steering torque applied by the steering motor 27. Then, the steering shaft 21 is rotated by the steering torque of the driver and the assist steering torque by the steering motor 27, and this rotational motion is converted into the lateral motion of the relay rod 23 by the steering gear box 22, and each tie rod 24L, 24R It is transmitted to each of the front wheels 10 _FL and 10 _FR to steer it. As a result, the load during steering is reduced, and an appropriate steering feeling corresponding to the vehicle speed is realized.

In VSC control, the target yaw rate gamma _t is calculated by equation (1), a power steering control, and calculates the assist steering torque by a map from the vehicle speed and the steering torque. Conventionally, the stability factor Kh in Equation (1) and the map used for calculating the assist steering torque are set based on the vehicle characteristics of the prototype vehicle. However, the same performance may not be exhibited due to crossing of individual parts constituting the vehicle or variations in alignment. Therefore, in the present invention, control parameters that match individual vehicles are set at the time of shipment and inspection.

  First, a method for setting the stability factor will be described. FIG. 5 is a flowchart for explaining this setting method. Here, the case of performing at the time of factory shipment will be described as an example, but it may be performed at the time of adjustment such as repair / inspection. This process is performed after the vehicle is finished.

  First, as a post-fitting process, a necessary map is stored in the map storage unit 43 of the ECU 4 (step S21). Next, the function inspection process is started. The zero point writing of the yaw rate sensor 51 and the lateral G sensor 52 is performed (step S22). Then, the yaw rate sensor 51 and the lateral G sensor 52 are checked (step S23). If the check fails, the process returns to step S22 and 0 point is corrected. If the check is passed, the braking force of each wheel is confirmed and the balance is adjusted (step S24).

Next, steady circular turning with a radius R is started at a constant vehicle speed V ₀ (the trajectory is shown in FIG. 6) (step S25), and the steering angle δ which is the output of the steering angle sensor 26 at that time, the yaw rate sensor The actual yaw rate γ _a that is the output of 51 and the lateral G · Gy that is the output of the lateral G sensor 52 are read (step S26). This steady circular turning may be performed by controlling the steering motor 27 so that the steering angle δ is constant.

  Next, it is determined whether or not the travel end condition is satisfied (step S27). When vehicle characteristic data sufficient for stability factor setting cannot be acquired, it is determined that the end condition is not satisfied, the process returns to step S26, and the steady circular turning is continued. On the other hand, when vehicle characteristic data sufficient for setting the stability factor can be acquired, it is determined that the end condition is satisfied, the steady circular turning is ended (step S28), and the following equation (2) is used. The stability factor Kh is obtained (step S29).

求めたスタビリティファクタＫｈとマップ記憶部４３内に格納されているスタビリティファクタＫｈ’との差分ΔＫｈを求め（ステップＳ３０）、この差分ΔＫｈの絶対値が所定のしきい値ΔＫｈthを超えている場合には、マップ記憶部４３内のスタビリティファクタＫｈ’の値を求めたスタビリティファクタＫｈに置き換え（ステップＳ３１）、ステップＳ２５へ戻り、スタビリティファクタＫｈの再検証を行う。一方、差分ΔＫｈの絶対値が所定のしきい値ΔＫｈth以下である場合には、制御パラメータであるスタビリティファクタＫｈと車両特性とが合致していると判定し、処理を終了する。

A difference ΔKh between the obtained stability factor Kh and the stability factor Kh ′ stored in the map storage unit 43 is obtained (step S30), and the absolute value of the difference ΔKh exceeds a predetermined threshold value ΔKhth. In this case, the value of the stability factor Kh ′ in the map storage unit 43 is replaced with the calculated stability factor Kh (step S31), the process returns to step S25, and the stability factor Kh is re-verified. On the other hand, when the absolute value of the difference ΔKh is equal to or smaller than the predetermined threshold value ΔKhth, it is determined that the stability factor Kh, which is a control parameter, matches the vehicle characteristics, and the process is terminated.

  This makes it possible to set a stability factor Kh that matches different vehicle characteristics for each individual vehicle, so that control accuracy such as VSC control using this stability factor Kh is improved, and vehicle control stability is also improved. improves. Further, when a common stability factor Kh is used in vehicles having different vehicle characteristics, it is difficult to perform fine control in consideration of the difference between the original vehicle characteristics and the vehicle characteristics assumed in the control. However, according to the present invention, by setting a control parameter that matches an individual vehicle, it is possible to perform control according to the characteristics of each vehicle and to perform fine control.

  Here, the case where one stability factor Kh is set regardless of the vehicle speed has been described as an example. However, steady circle turning is performed at a plurality of vehicle speeds, and the stability factor Kh is changed according to the vehicle speed. Also good. Moreover, the calculation accuracy of the stability factor Kh may be improved by performing steady circular turning on a plurality of circles having different radii.

  Here, the provisional stability factor Kh is stored in advance in the map storage unit 43 as an initial value. However, for the control parameter (here, the stability factor Kh) to be set by measurement, step S21 is performed. Then, the setting may not be performed, or a temporary value such as a design value may be set.

  Next, a method for setting the steering characteristics will be described. FIG. 7 is a flowchart for explaining this setting method. As in the case of the stability factor Kh setting, the case where it is performed at the time of factory shipment will be described as an example, but it may be performed at the time of adjustment such as repair / inspection. This process is performed after the vehicle is finished. Here, only the setting part corresponding to steps S25 to S30 in FIG. 5 will be described. The other parts are the same as those in FIG.

First, a test running is started in which the steering angle δ is changed at a predetermined cycle at a constant vehicle speed V (step S41), the steering angle δ that is the output of the steering angle sensor 26 at that time, and the actual yaw rate that is the output of the yaw rate sensor 51. γ _a and the lateral G · Gy output from the lateral G sensor 52 are read (step S42). This steady circular turning may be performed by controlling the steering motor 27 so that the change of the steering angle δ has a desired cycle. FIG. 8 shows an example of a change in the cycle of the steering angle δ during the test travel. Here, it is changed so that δ = δmax × sin (t × ω). The example of the cycle change is not limited to such sine steering. As shown in FIG. 9, after steering to the maximum steering angle δmax with a constant steering angular velocity, the steering is performed in the reverse direction at the same steering angular velocity to the steering angle −δmax. Further, it may be a sawtooth wave-like period change that returns the steering angle to 0 at the same steering angular velocity in the same steering direction as the first time.

Next, it is determined whether or not the travel end condition is satisfied (step S43). If the cycle change has not ended, the process returns to step S42 and the test running is continued. On the other hand, when it is completed to periodic change ends the test run (step S44), and calculates the slip angle theta _s based on the following equation (3) (step S45).

（３）式における実ヨーレートγｔと横加速度Ｇｙは、いずれも最大値である。次に、このθ_ｓを最大操舵角δmaxの異なる所定個数の組み合わせ（最低３個）について取得したか否かを判定する（ステップＳ４６）。所定個数に達していない場合には、δmaxを変えてテスト条件を変更し（ステップＳ４７）、ステップＳ４１へと戻り、再度テスト走行を行う。所定個数に達している場合には、操舵角δとスリップ角θｓとの対応を調べる（ステップＳ４８）。

The actual yaw rate γt and the lateral acceleration Gy in equation (3) are both maximum values. Next, it is determined whether or not θ _s has been acquired for a predetermined number of combinations (at least three) having different maximum steering angles δmax (step S46). If the predetermined number has not been reached, δmax is changed to change the test condition (step S47), the process returns to step S41, and the test run is performed again. If the predetermined number has been reached, the correspondence between the steering angle δ and the slip angle θs is examined (step S48).

  FIG. 10 shows an example of correspondence between the steering angle δ and the slip angle θs in an actual vehicle. A to D are all the same vehicle type. Compared to Car C, which shows specifications close to the design values, Car A and Car D are stable but have poor turning performance, and Car B has good turning followability but poor stability.

  In step S48, for example, it is determined whether or not the correspondence is appropriate based on whether or not the total sum of squares (sum of squares) of deviation from the appropriate slip angle θs is smaller than a threshold value. When the sum of squares is equal to or less than the threshold value and the correspondence relationship is determined to be appropriate, it is determined that the assist steering characteristic that is a control parameter is appropriate, and the process ends. On the other hand, when the sum of squares exceeds the threshold value and it is determined that the correspondence relationship is not appropriate, the assist stored in the map storage unit 43 so that the correspondence relationship between the steering angle δ and the slip angle θs is appropriate. The steering characteristic is corrected (step S49). Specifically, the assist ratio, gear ratio, etc. are changed. In the case of the A, B, and D cars shown in FIG. 10, the A and D cars make the steering wheel 20 lighter by making the assist ratio larger or the like, thereby facilitating steering. On the other hand, in the case of the B car, the steering wheel 20 is made heavy by reducing the assist ratio or the like to reduce the slip angle during turning. After the correction, the process returns to step S41, and the correction data is verified by performing a test run again.

  Thus, the turning characteristic of the vehicle can be adjusted by adjusting the steering assist characteristic in accordance with the vehicle characteristic. Also, the left / right balance can be adjusted. Here, the deviation between the steering angle δ and the slip angle θs from the target state is determined from a plurality of combinations (data sets), but the specific steering angle δx and the target state of the slip angle θs at that time are determined. The steering assist characteristic may be adjusted by estimating the tendency based on the deviation. In this case, the adjustment accuracy with the vehicle characteristics is inferior, but there is an advantage that only one test run is required.

  In the above description, the example in which the vehicle characteristics are measured at the final stage of the manufacturing process has been described. However, the vehicle characteristics are measured when the vehicle moves on the line during the manufacturing process, and the control parameters are adjusted based on the measured vehicle characteristics. May be performed.

It is a schematic block diagram of the vehicle provided with the vehicle behavior control apparatus used as the object of the adjustment method of the vehicle behavior control apparatus concerning this invention. It is a block block diagram of the vehicle of FIG. It is a flowchart which shows the example of a control process of VSC control. It is a flowchart which shows the control processing example of a power steering apparatus. It is a flowchart explaining the setting method of the stability factor Kh concerning this invention. It is a figure which shows the locus | trajectory of steady circle turning driving | running | working. It is a flowchart explaining the setting method of the steering characteristic concerning this invention. It is a figure which shows the example of a period change of the steering angle in the case of test running. It is a figure which shows another example of the period change of the steering angle at the time of test driving | running | working. It is a figure which shows the example of a response | compatibility with steering angle (delta) and slip angle (theta) s in a real vehicle.

Explanation of symbols

3 _{FL to} 3 _RR ... brake device, 6 ... drive system, 10 _FL to 10 _RR ... wheels, 12 _{FL to} 12 _RR ... wheel speed sensor, 20 ... steering wheel, 21 ... steering shaft, 22 ... steering gear box, 23 ... relay rod, 24L, 24R ... tie rod, 25 ... steering torque sensor, 26 ... steering angle sensor, 27 ... steering motor, 30 ... brake _actuator, 31 FL to 31 _{RR ...} wheel cylinder, 43 ... map storage unit, 51 ... yaw rate sensor 52 ... Sensors.

Claims (5)

An adjustment method for a vehicle behavior control device during vehicle inspection and adjustment,
Obtaining a characteristic value of the vehicle while traveling in a predetermined steering pattern at a constant vehicle speed;
A step of setting a reference value for control of the vehicle behavior control device based on the obtained characteristic value;
The adjustment method of the vehicle behavior control apparatus characterized by the above-mentioned.   2. The vehicle according to claim 1, wherein the reference value of the control is a stability factor, the predetermined steering pattern is a constant steering angle, and the vehicle characteristic values to be obtained are a lateral acceleration and a yaw rate. Adjustment method for behavior control device.   3. The method for adjusting a vehicle behavior control device according to claim 2, wherein a stability factor corresponding to each vehicle speed is obtained by changing the constant vehicle speed.   The reference value of the control is an assist ratio of the assist steering torque to the steering torque, and the predetermined steering pattern is a steering pattern having a predetermined steering angle as an amplitude at a constant cycle, and a vehicle characteristic value to be obtained is 2. The method for adjusting a vehicle behavior control apparatus according to claim 1, wherein the adjustment is a slip angle.   5. The method for adjusting a vehicle behavior control device according to claim 4, wherein the assist ratio is set by obtaining a slip angle for a plurality of steering patterns having different steering angles as amplitudes.

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