JPH0481316A - Integrated control device for vehicle - Google Patents

Abstract

PURPOSE:To control a steering device and a suspension device of a vehicle integrally to obtain a high performance turning characteristic with the simple structure by applying a linear control theory in a linear system including a new variable after converting a control variable in a suspension system control for giving influence to the turning movement with non-linear conversion. CONSTITUTION:A steering quantity of a steering wheel and a behavior quantity showing the turning movement of a vehicle are detected by a means 1, and a target steering control quantity is computed by a means 2 on the basis of the steering quantity, while a target behavior quantity being computed similarly by a means 3. A suspension correction quantity and a steering correction quantity are integrally computed by a means 4 on the basis of a linear model in response to the target behavior quantity and a real behavior quantity, while the suspension correction quantity is non-linear converted on the basis of the real behavior quantity to output a real suspension correction quantity with a means 5. Furthermore, a means 7 controls so that an optimum steering angle is generated at least on one of front wheels and rear wheels of a vehicle in response to the target steering control quantity and the steering correction quantity. Suspension characteristic of each wheel is controlled by a means 8 in response to a real suspension correction quantity and a position control quantity.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an integrated control system for a vehicle that integrally controls a steering system and a suspension system of a vehicle to obtain high-performance turning characteristics that take into account, for example, the behavior of the suspension system or the influence on the steering system.

[Prior art and its problems]

2. Description of the Related Art Conventionally, there are devices that control the turning motion characteristics of a vehicle through active control. This conventional vehicle motion control device detects the steering wheel steering amount and vehicle behavior amount, calculates the target control amount necessary to obtain the target dynamic characteristics from the steering wheel steering amount, and generates a feed forward signal. The forward signal calculation means calculates the amount of deviation between the target vehicle behavior amount and the vehicle behavior amount calculated based on the steering wheel steering amount, and calculates the optimum correction amount based on the vehicle condition from this deviation amount. , a feedback signal calculation means for generating a feedback signal; a control signal calculation means for adding and subtracting the feedforward signal and the feedback signal to calculate a steering control signal; ``vehicle steering control signal (patent application 1-132166)
No.). Further, the turning motion characteristics of the vehicle can also be controlled by controlling the load on the suspension. This conventional vehicle motion control device detects the amount of steering wheel steering, the amount of steering system behavior of the vehicle, the amount of state of the vehicle in the horizontal direction, and the amount of state of the vehicle in the vertical direction, and suppresses the vibration that occurs in the suspension from the amount of state in the vertical direction. A vibration suppression control signal calculation means for outputting a vibration suppression control signal, a target behavior amount calculation means for outputting a target behavior amount signal which is a target value of the steering system behavior amount from the steering amount, and a target behavior amount signal and the steering system behavior amount. a suspension system influence amount calculation means for calculating the amount of influence that the vehicle state has on the suspension system from the horizontal state amount and outputting it as a suspension system influence amount signal; a non-interference control signal calculating means for calculating a control signal for maintaining the attitude of the vehicle body and compensating the vehicle behavior of the steering system from the deviation signal and the suspension system influence amount signal and outputting it as a non-interference control signal; and vibration suppression control. A non-interference device for vibration control and a suspension device comprising an integrated control signal calculating means for calculating an integrated control signal from the signal and a non-interfering control signal, and an actuator means for controlling the characteristics of the suspension based on the integrated control signal. Integrated control device (Patent application Hei 1-1
No. 43325). When these steering control signals and suspension integrated control devices are used at the same time, they can further improve the control effect on turning motion by effectively utilizing the effects of suspension system motion, such as stability factor changes due to load movement. can. However, the control of the turning motion performed by the two devices interferes with each other in terms of performance, and designing them simultaneously requires a lot of trial and error.

[Purpose of the invention]

An object of the present invention is to integrally control a vehicle's steering system and suspension system to obtain high-performance turning characteristics. By the way, in the above-mentioned conventional technology, since the control law for steering and the control law for suspension are independent for one movement, ie, turning, a lot of trial and error was required when designing each control law. However, since the influence of the suspension system on turning motion is nonlinear, it is not possible to apply linear control theory by simply combining these two control systems, and the design requires much trial and error. I have no choice but to. Therefore, in the present invention, we focus on the fact that a system that includes new variables after nonlinear transformation of suspension system control variables that affect turning motion can be regarded as a linear system, and apply linear control theory to this linear system. By applying this method, the aim is to obtain excellent turning characteristics with a simple configuration that takes into account the nonlinear effects of the suspension system on turning motion.

[Description of the invention]

As shown in FIG. 1, the present invention includes a detection means 1 for detecting at least a steering amount of a steering wheel and a behavior amount representing a turning motion of the vehicle, and a detection means 1 for detecting a behavior amount representing a steering amount of a steering wheel and a turning motion of a vehicle, a target steering control amount calculation means 2 for calculating a target steering control amount for achieving a behavior amount; a target behavior amount calculation means 3 for calculating a target vehicle behavior amount based on the detected steering amount; Correction amount calculation means that integrally calculates a suspension correction amount and a steering correction amount for correcting the calculated target steering control amount based on a linear model according to the calculated target behavior amount and the detected behavior amount. 4, nonlinear compensation means 5 for nonlinearly converting the calculated suspension correction amount based on the detected behavior amount and outputting an actual suspension correction amount representing suspension characteristics; a steering control drive means 7 that produces an optimal steering angle for at least one of the front wheels and rear wheels of the vehicle according to the steering angle, and variably controls the suspension characteristics of each wheel according to the actual suspension correction amount and the attitude control amount. The suspension control drive means 8 is provided with a suspension control drive means 8. The operation of the vehicle integrated control device of the present invention having the above configuration is as follows. The detection means 1 detects behavioral quantities representing the amount of steering wheel steering, turning motion of the vehicle, etc., and converts them into electrical signals corresponding thereto. Next, in order to optimize the behavior of the vehicle with respect to the steering amount, the target steering control amount calculation means 2 calculates the target steering control amount necessary to achieve the target vehicle behavior amount from the steering amount based on the dynamic characteristics of the vehicle behavior. is calculated taking into consideration, and output as a feedforward control amount in controlling the behavior amount,
Improves vehicle responsiveness to steering. Note that this target dynamic characteristic of the vehicle is a dynamic characteristic that is easiest for the driver to maneuver. Further, the target behavior amount calculation means 3 calculates a target behavior amount that is a behavior amount of the target vehicle including dynamic characteristics. Next, in order to suppress deviations in the behavior amount caused by crosswinds and road disturbances, the correction amount calculation means 4 integrates the steering correction amount and the suspension correction amount related to the suspension characteristics that affect turning movement based on a linear model. It calculates and outputs it as a feedback control amount in controlling the behavior amount, improving the stability of the vehicle. Then, the steering control signal calculation means 7 adds or subtracts the target steering control amount, which is a feedforward control amount, and the steering correction amount, which is a feedback control amount, and based on the calculation result, at least one of the front wheels or the rear wheels is controlled. The steering actuator is driven to give the steering wheel an optimal turning angle. On the other hand, the nonlinear compensating means 5 nonlinearly transforms the calculated suspension correction amount using the behavior amount.
The actual suspension correction amount, which is a direct control parameter of the suspension system, is output. Then, the suspension control drive means 8 drives the suspension actuators of each wheel based on the actual suspension correction amount for controlling the behavior amount, and variably controls the suspension characteristics. Focusing on the control of the amount of behavior, if there are no changes in vehicle specifications or disturbances from the external environment, the amount of behavior can be matched to the target amount of behavior using the target steering control amount, which is a feedforward control amount in controlling the amount of behavior. Therefore, the deviation becomes zero, and the steering correction amount and suspension correction amount, which are feedback control amounts in controlling the behavior amount, also become zero, and the feedback control does not work. A suspension correction amount of zero corresponds to the fact that the roll caused by turning is evenly supported by the front and rear suspensions, which prevents twisting of the vehicle body and distributes the load as evenly as possible to each wheel. It controls the suspension. Therefore, when there are no changes in the vehicle specifications or disturbances from the external environment, control can be performed that does not place a burden on the vehicle body and leaves a margin for tire force. On the other hand, if there are variations in vehicle specifications or disturbances from the external environment, it is not possible to obtain the target behavior amount only with feedforward control, and deviations occur. in this case,
A steering correction amount and a suspension correction amount corresponding to the deviation are output. These correction amounts work to asymptotically approach the deviation to zero, and the dynamic characteristics of the vehicle can be asymptotically approached to the target behavior amount. In this way, the vehicle integrated control device of the present invention integrally uses the suspension correction amount in addition to the steering correction amount as a feedback control amount in controlling the behavior amount, and the deviation can be reduced to zero by only the steering correction. It is possible to asymptote more quickly than when asymptotic to , and it is possible to achieve vehicle motion that is more robust against vehicle fluctuations and more stable against external disturbances. That is, in the present invention, since a suspension correction amount linear with respect to a behavior amount is used as a control input, a target control characteristic can always be obtained with good response with a relatively simple configuration. Moreover, since the actual suspension correction amount representing the suspension characteristics is calculated by finally nonlinearly converting this suspension correction amount using the behavior amount, it is possible to accurately reflect the nonlinear influence on the suspension characteristics or turning movement. can. Therefore, there is an excellent effect that turning characteristics with high responsiveness and stability can always be obtained, taking into account not only the steering characteristics but also the suspension characteristics. Furthermore, the relationship between the actual steering angle of the front and rear wheels, which is the amount of steering correction, and the behavior quantity that represents the turning motion of the vehicle, etc., is expressed by a linear differential equation, whereas the relationship between the actual suspension correction amount, which represents the suspension characteristics, and the turning motion. is expressed not as a linear differential equation but as a nonlinear linear differential equation. For this reason, when attempting to design a control system using the actual suspension correction amount as a direct control input, as in the past, linear control theory cannot be applied, resulting in a trial-and-error design process, resulting in the optimal control system for the purpose. The problem was that it was difficult to obtain. Therefore, in the present invention, a suspension correction amount related to the suspension characteristics that affects the turning motion of the vehicle, which is determined by nonlinear variable conversion, is derived from the actual suspension correction amount, and a control system is designed using this suspension correction amount as a control input. conduct. In this case, since the amount of behavior, the amount of steering correction, and the amount of suspension correction are in the relationship of a linear differential equation described by a transfer function, it is possible to apply linear control theory, and it is relatively easy to make steering correction from the deviation. It is possible to design a correction amount calculation means 4 for integrally calculating the amount and the suspension correction amount.

[Description of other inventions]

Other inventions are embodiments of the present invention described above, and as shown in FIG. a steering amount detection means 12 that outputs a steering amount signal;
A behavior amount detection means 13 detects the amount of behavior of the vehicle and outputs a behavior amount signal, a state amount detection means 15 detects the state amount of the vehicle and outputs a state amount signal, and a state amount detection means 15 detects the actual steering angle of the steered wheels. Actual steering angle detection means 14 that outputs a steering angle signal, and target steering control amount calculation means 2o that calculates a target steering control amount for achieving a target vehicle behavior amount based on the vehicle speed signal from the steering amount signal. , target behavior amount calculation means 3o that calculates a target behavior amount of the vehicle based on the vehicle speed signal from the steering amount signal, and deviation calculation means 41 that calculates the deviation between the target behavior amount signal and the behavior amount signal. and a correction amount calculation means 40 that calculates an optimal steering correction amount and suspension correction amount based on the disturbance acting on the vehicle from the deviation amount signal, and a correction amount calculation means 40 that adds or subtracts the target steering control amount signal and the steering correction amount signal. A steering control signal calculation means 70 having an adder/subtractor that uses the steering control signal as a control signal, a steering drive means 71 that amplifies the power of the steering control signal into a steering actuator drive signal, and a steering control signal calculation means 70 that amplifies the power of the steering control signal into a steering actuator drive signal, a steering actuator means 72 that dampens at least one of the steered wheels so as to give an optimum steered angle; nonlinear compensating means 50 for calculating an actual suspension correction amount; and target attitude control amount calculating means 6 for calculating a target attitude control amount for predicting and suppressing a change in attitude of the vehicle body from the vehicle speed signal and the target behavior amount signal.
1, an attitude control correction amount calculation means 62 that calculates an attitude control correction amount from the state quantity, and an attitude control correction amount calculation means 62 that calculates an attitude control amount for maintaining the attitude of the vehicle body from the target attitude control amount signal and the attitude control correction amount signal. a suspension control signal calculation means 80 for calculating a suspension control signal for compensating the turning movement and maintaining the attitude from the actual suspension correction amount signal and the attitude control amount signal; It comprises a suspension drive means 81 for power amplifying a control signal into a suspension actuator drive signal, and a suspension actuator means 82 for variably controlling the suspension characteristics of the four wheels based on the power amplified suspension actuator drive signal. The operation of the vehicle integrated control device of the other invention having the above configuration is as follows. The vehicle speed detection means II detects the moving speed of the vehicle and converts it into a corresponding electrical signal or the like. Further, the steering amount detection means 12 detects the steering amount of the steering wheel and converts it into a corresponding electric signal or the like. Further, the behavior amount detection means 13 detects a behavior amount representing the turning movement of the vehicle and converts it into a corresponding electric signal or the like. Further, a state quantity detecting means 15 detects a state quantity representing the attitude of the vehicle body and converts it into a corresponding electric signal or the like. Furthermore, the actual steering angle of the steered wheels is detected by the actual steering angle detection means 14 and converted into a corresponding electric signal or the like. Next, in order to optimize the behavior of the vehicle with respect to the steering amount, the target steering control amount calculation means 20 calculates the target steering control amount necessary to achieve the target amount of vehicle behavior based on the steering amount, vehicle speed, etc. This calculation takes into account the dynamic characteristics of the vehicle and outputs it as a feedforward control amount in controlling the behavior amount, improving the vehicle's responsiveness to steering. Note that this target dynamic characteristic of the vehicle is a dynamic characteristic that is easiest for the driver to maneuver. Further, the target behavior amount calculation means 30 calculates a target behavior amount that is a behavior amount of the target vehicle including dynamic characteristics. Next, the deviation calculation means 41 calculates the deviation between the target behavior amount and the behavior amount. Next, the correction amount calculating means 40 integrally calculates the steering correction amount and the suspension correction amount in order to suppress deviations in the behavior amount caused by crosswinds and road surface disturbances, and uses the steering correction amount and the suspension correction amount as feedback control amounts in controlling the behavior amount. output and improve vehicle stability. Then, the steering control signal calculation means 70 adds and subtracts the target steering control amount, which is a feedforward control amount, and the steering correction amount, which is a feedback control amount, to generate a steering control signal. Next, the steering control signal is amplified into a steering actuator drive signal for driving a steering actuator in a steering drive means 71, and this steering actuator drive signal is amplified in a steering actuator 72 to provide optimum steering for at least one of the front wheels and the rear wheels. The steering actuator is driven to give a steering angle. In addition, the nonlinear compensation means 50 nonlinearly transforms the suspension correction amount using the vehicle speed, behavior amount, and actual steering angle, thereby outputting an actual suspension correction amount that is a direct control parameter of the suspension system. Further, the target attitude control amount calculation means 61 outputs a target attitude control amount from the vehicle speed and the target behavior amount as a feedforward control amount in attitude control to offset the influence of the behavior amount, vehicle speed change, etc. on the attitude. do. Further, the attitude control correction amount calculation means 62 outputs the attitude control correction amount from the state quantity as a feedback control amount in attitude control. Next, the attitude control calculation means 60 calculates an attitude control amount for maintaining the attitude by adding or subtracting the target attitude control amount, which is a feedforward control amount, and the attitude division correction amount, which is a feedback control amount. . Next, suspension control signal calculation means 80 performs suspension control to obtain a desired amount of behavior while maintaining the posture based on the actual suspension correction amount for controlling the amount of behavior and the amount of attitude control for controlling the attitude. Output a signal. Next, the suspension control signal is amplified into a suspension actuator drive signal for driving the suspension actuator of each wheel in the suspension drive means 81, and based on this suspension actuator drive signal, the suspension actuator 82 of each wheel is driven to vary the suspension characteristics. Control. Focusing on controlling the amount of behavior, if there are no changes in vehicle specifications or disturbances from the external environment, the amount of behavior is made to match the target amount of behavior using the target steering control amount, which is a feedforward control amount in controlling the amount of behavior. Therefore, the deviation becomes zero, and the steering correction amount and suspension correction amount, which are feedback control amounts in controlling the behavior amount, also become zero, and the feedback control does not work. A suspension correction amount of zero corresponds to the fact that the roll caused by turning is evenly supported by the front and rear suspensions, which prevents twisting of the vehicle body and distributes the load to each wheel as evenly as possible. It controls the suspension. therefore,
In this way, when there are no changes in the vehicle specifications or disturbances from the external environment, control is performed that does not place a burden on the vehicle body and leaves a margin for tire force. On the other hand, if there are variations in vehicle specifications or disturbances from the external environment, it is not possible to obtain the target behavior amount only with feedforward control, and deviations occur. in this case,
A steering correction amount and a suspension correction amount corresponding to the deviation are generated. These correction amounts work to make the deviation asymptotic to zero,
The dynamic characteristics of the vehicle can be made to asymptotically approach the target behavior amount. In this way, in the vehicle integrated control device of the other invention,
In addition to the steering correction amount, the suspension correction amount is integrally used as a feedback control amount in controlling the behavior amount, and the deviation is asymptotically approached to zero more quickly than when the deviation is asymptotically approached to zero only by steering correction. This makes it possible to achieve excellent vehicle motion with robustness against vehicle fluctuations and stability against disturbances. Furthermore, since the amount of behavior, steering correction amount, and suspension correction amount are in the relationship of a linear differential equation described by a transfer function, it is possible to apply linear control theory, and it is relatively easy to calculate the steering correction amount from the deviation. A correction amount calculating means 40 for determining the suspension correction amount can be designed. Here, an example of the calculation contents of the nonlinear compensation means 50 will be explained in more detail with reference to FIGS. 3 and 4. The characteristics of tires used in vehicles exhibit nonlinear characteristics with respect to the ground contact load, and as shown in FIG. 3, the cornering force exhibits saturation characteristics with respect to the ground contact load. Therefore, when the total ground loads are equal, the total cornering force for the left and right wheels reaches its maximum value when there is no load difference between the left and right wheels, as shown in FIG. 4, and decreases as the load difference increases. The present invention utilizes this property to control vehicle behavior such as turning characteristics. That is, when the front wheel suspension suppresses roll motion caused by turning, etc., no load difference occurs between the rear wheels, but a load difference between the left and right front wheels is required to maintain the posture of the vehicle. As a result, the cornering force on the front wheels decreases, which has the same effect as returning the steering angle of the front wheels. Furthermore, when the rear wheel suspension suppresses roll motion caused by turning, etc., the front wheels do not experience a load difference, whereas the rear wheels create a load difference between the left and right wheels that is necessary to maintain the posture of the vehicle. As a result, the cornering force on the rear wheels decreases, which has the same effect as returning the steering angle of the rear wheels. In the end, vehicle motion that takes these phenomena into account can be described using the following equation. mv(β+R)=F,+F,-(1)1,R
=a, Fl-a, F, ... (2)
F+=-cr(β+a+R/v-δI)・(Ik
rl vRl(1+λ))−(3)Fr=−c,(β−
a, R/v−δ, )・(1−, l vR1(1−λ>
) - (4) However, a ft a r: Distance between the axle of the front and rear wheels and the center of gravity cf+cr: Cornering power of the front and rear wheels Fr, F
, : Cornering force It of front and rear wheels : Yaw moment of inertia m : Vehicle mass R : Yaw angular velocity V Second vehicle speed β : Vehicle body slip angle δ1. δ1: Actual steering angle of front and rear wheels Also, krlvRl(1+λ) and kTlvR(l-
λ) is a term representing a decrease in cornering power due to load transfer between the left and right wheels. λ (-1≦λ≦1) is a value related to suspension system control; λ=1 means that the roll moment generated during turning is supported by the front wheel suspension, and λ=-1 means that the rear wheel suspension supports it. It corresponds to what it supports. By the way, as can be seen from equations (1) to 4), the actual suspension correction amount λ, which is a direct control parameter of the suspension system, is expressed as a nonlinear element of a differential equation regarding the vehicle body slip angle β and the yaw angular velocity R. However, when a nonlinear transformation as shown in the following equation is performed, equations (1) to 4) are linearized quite strictly. p=kIl vRl (1+λ) ・(β+a, R/v−δl) C, a r k, 1vR1(1−λ) rF1t ・(β−a, R/v−δ,) ・・・(5)( 5)
(1) or 4) using the suspension correction amount p after converting the equation.
By linearly approximating the differential equation of Eq., the following equation is obtained. x=Ax+Bu−(6)x=
[β, R]” ... (7) u
= [δ7. δ,, p]" ... (8) However, mv However, t 8 mouths 0 mv r B12: mv I Therefore, the correction amount calculation means 40 is (6) or 10)
Based on the formula, a control system that makes the deviation zero may be configured. In other words, equations (6) to 10) represent linear controlled objects in a multi-input multi-output system, so by applying linear control theory, they can be easily and quickly calculated, and are always responsive and appropriate. This makes it possible to control the system easily and to easily design the control system. In addition, the inverse transformation of equation (5) is, however, Δ+−crarkrlvR1(β0al two δ,)
■ A, = c, a, krl vRl (β-a, -
δr)■ Therefore, the nonlinear compensation means 50 converts the suspension correction amount p into the actual suspension correction amount λ according to equation (11).

【Example】

The integrated control system for a vehicle according to the present invention will be explained with reference to FIG. The vehicle integrated control device of this embodiment is applied to a front and rear wheel steering device and a four-wheel suspension device of a vehicle, and includes a vehicle speed detection means 11, a steering amount detection means 12, a behavior amount detection means 13, and a state quantity. Detection means 15 and actual steering angle detection means 1
4, target steering control amount calculation means 20, target behavior amount calculation means 30, deviation calculation means 41, and correction amount calculation means 40.
, steering control signal calculation means 70 , steering drive means 71 , steering actuator means 72 , and nonlinear compensation means 50
, a target attitude control amount calculation means 61 , an attitude control correction amount calculation means 62 , an attitude control amount calculation means 60 , a suspension control signal calculation means 80 , a suspension drive means 81 , and a suspension actuator means 82 . The vehicle speed detection means 11 includes a vehicle speed sensor 110, calculates the vehicle speed from the rotational speed of the driven wheels, and outputs a corresponding electric signal as a vehicle speed signal V. The steering amount detection means 12 consists of a steering angle sensor 120 installed coaxially with the steering wheel, and measures the steering angle of the steering wheel and divides it by a value corresponding to the steering wheel gear ratio to calculate the steering angle when no steering control is performed. A value corresponding to the actual front wheel steering angle is output as a steering amount signal δ, . The behavior amount detection means 13 includes a vehicle body slip angle sensor 131 and a yaw angular velocity sensor 132. The vehicle slip angle sensor 131 uses a non-contact speedometer, and converts the vehicle slip angle β into an electrical signal and outputs it. Further, the yaw angular velocity sensor 132 is attached to the vehicle center of gravity, measures the yaw angular velocity at the center of gravity, and measures the yaw angular velocity R.
Outputs a signal representing . The state quantity detection means 15 includes a roll angle sensor 150. The roll angle sensor 150 determines the roll angle from the suspension length of each wheel, and outputs a signal representing the roll angle φ. The actual steering angle detection means 14 includes a front wheel actual steering angle sensor 141 and a rear wheel actual steering angle sensor 142. Front wheel actual steering angle sensor 141
measures the actual steering angle δ of the front wheels and outputs a corresponding signal. Further, the rear wheel actual steering angle sensor 142 measures the actual steering angle δ of the rear wheels and outputs a corresponding signal. Target steering control amount calculation means 20 and target behavior amount calculation means 3
0, deviation calculation means 4I, correction amount calculation means 40, steering control signal calculation means 70, nonlinear compensation means 50, target attitude control amount calculation means 61, attitude control correction amount calculation means 62, attitude control The calculation means consisting of the quantity calculation means 60 and the suspension control signal calculation means 80 inputs the vehicle speed signal, the steering amount signal, the behavior amount signal, the state amount signal, and the actual steering angle signal of the front and rear wheels, and calculates the steering control signal of the front and rear wheels. and a digital computer that outputs suspension control signals for each wheel. The contents of calculations performed by each calculation means will be explained below. The target behavior amount calculation means 30 calculates the steering amount signal δ8. Based on the vehicle speed signal ■, the target vehicle body slip angle β0 and target yaw angular velocity R, which are the vehicle behavior quantities that make it easiest for the driver to maneuver, are determined.
6 is output as the target vehicle behavior amount. Here, as the dynamic characteristics of such vehicle behavior, we will consider the characteristics in which the vehicle body slip angle is zero and the yaw angular velocity follows the steering with a first-order lag. Next, the steering amount signal δ81, the vehicle speed signal V, and the target vehicle body slip angle β. , a mathematical expression representing the relationship between target yaw angular velocity R6 is shown. β, = 0 ... (12
) However, T represents the time constant of the first-order lag, and S represents the Laplace operator. The calculation of equation (13) is performed as a discretized recurrence formula. The target steering control amount calculation means 20 calculates a target vehicle body slip angle β which is a target vehicle behavior amount. The front wheel target steering control amount signal δ, I and the rear wheel target steering control amount signal δr+ necessary to obtain the target yaw angular velocity R0 are calculated as feedforward control amounts for the behavior amount. Next, the calculation contents of the target steering control amount calculation means 20 will be explained. There is a relationship between the actual steering angle of each wheel and the amount of behavior expressed by equations (6) to 10. This property is expressed as (12), (
In order to obtain the target dynamic characteristics expressed by equation 13), the steering amount δ8w and the actual steering angle δ1 of the front and rear wheels must be adjusted. The following dynamic characteristics are required between δ. ...(17) ...(19) Therefore, the calculation by the target steering control amount calculation means 20 is (
14) or 19) is discretized and δ becomes δ14, δ
, is δ1. . The deviation calculating means 41 calculates a target vehicle body slip angle β which is a target behavior amount. Then, the deviation between the target yaw angular velocity R6 and the measured behavior quantities, vehicle body slip angle β and yaw angular velocity R, is calculated and output as a deviation signal. The correction amount calculation means 40 calculates the vehicle body slip angle deviation signal β0−
From β and yaw angular velocity deviation signal RO-R, front wheel steering correction amount signal δ, b, rear wheel steering correction amount signal δ7b and A suspension correction amount signal p is calculated and output. The algorithm for this operation is (6) or 10
) is the control law that uses the linear state equation as the control object. That is, in the case of this embodiment,
e, Bc, and Cc calculate δfb+δrb+p using constant matrices. In this way, since equations (6) and 1O) are linear equations of state, it is possible to apply linear control theory. In this case, the control law includes dynamic characteristics. This control law is discretized and becomes a recurrence formula. Further, the control law may be state feedback. The steering control signal calculating means 70 adds the front wheel target steering control amount δf obtained from the target steering control amount calculating means 20 and the front wheel steering correction amount signal δfb obtained from the correction amount calculating means 40 to generate a front wheel steering control signal. δ, 0, and the rear wheel target steering control amount δ7. obtained from the target steering control amount calculating means 20. and,
Rear wheel steering correction amount signal δ obtained from correction amount calculation means 40
7. are added and the rear wheel steering control signal δ7° is combined, the front wheel steering control signal δ,0 and the rear wheel steering control signal δ,. is output as a steering control signal. The nonlinear compensation means 50 calculates the suspension correction amount signal p obtained from the correction amount calculation means 40, the vehicle speed signal V obtained from the vehicle speed detection means 11, the vehicle body slip angle signal β obtained from the behavior amount detection means 13, and the yaw. Angular velocity R and actual steering angle detection means 14
Front wheel actual steering angle signal δ, rear wheel actual steering angle signal δ, obtained from
Based on this, the actual suspension correction amount signal λ is calculated according to equation (11). The target attitude control amount calculation means 61 uses the vehicle speed signal V obtained from the vehicle speed detection means 11 and the target yaw angular velocity R0 obtained from the target behavior amount calculation means 30 to suppress roll due to turning and maintain the attitude. The required moment of force is calculated as a target attitude control amount signal MXf, which is a feedforward attitude control amount. Next, the specific contents of the calculation in the target attitude control amount calculation means 61 will be explained. It is predicted that a lateral acceleration given by the following equation will occur at the vehicle center of gravity position during a turn from the vehicle speed signal V and the target yaw angular velocity R0. g −” V Ro −(
20) Furthermore, since a roll moment corresponding to this lateral acceleration is generated around the vehicle center of gravity, the following equation is derived as a moment of force to offset this. Mxt=-mgyh=-mvRoh-(21
) However, h represents the height of the center of gravity. That is, the specific calculation formula of the target attitude control amount calculation means 61 is equation (21). The attitude control correction amount calculation means 62 multiplies the roll angle signal Φ obtained from the state quantity detection means 15 by a certain gain to obtain an attitude control correction amount signal M,> as a feedback control amount for attitude control. calculate. M, b=-GΦ (22) However, G is a gain for asymptoticing the roll angle Φ to zero. The attitude control amount calculation means 60 is the target attitude control amount calculation means 6.
The target attitude control amount signal Mxr obtained from 1 and the attitude control correction amount signal M obtained from the attitude control correction amount calculation means 62.
□ and calculates the moment of force required to maintain the posture by setting the attitude control amount signal M, (1). λ and attitude control amount calculation means 60
Attitude control amount signal M, obtained from . From this, a suspension control force is calculated and output as a suspension control signal to maintain the attitude and correct the amount of behavior to the target value. However, fl: Left front wheel suspension control force f2: Right front wheel suspension control force f3: Left rear wheel suspension control force f4: Right rear wheel suspension control force Tf: Front wheel tread T7: Rear wheel tread The steering drive means 71 outputs a steering control signal. Front wheel steering control signal δ, outputted as a steering control signal from calculation means 70. and rear wheel steering control signal δ,. It is comprised of amplifiers 711 and 712 which input the signals and convert them into front wheel steering actuator signals and rear wheel steering actuator signals, respectively. The steering actuator means 72 includes a front wheel steering actuator 721 and a rear wheel steering actuator 722 that steer the front and rear wheels based on the front wheel steering actuator signal and the rear wheel steering actuator signal output from the steering drive means 71. The suspension drive means 81 receives suspension control force signals f2, , f2, as suspension control signals outputted from the suspension control signal calculation means 80. Input f,, -f,
Amplifier 811゜81 for converting into suspension actuator signal
Consists of 2.813,814. The suspension actuator means 82 includes force generators 821, 822, 823, 824 that variably control the suspension control force of the four wheels based on the suspension actuator signal output from the suspension drive means 81. The functions and effects of this embodiment having the above configuration are as follows. First, the outputs of the vehicle speed sensor 110, steering angle sensor 120, body slip angle sensor 131, yaw angular velocity sensor 132, roll angle sensor 150, front wheel actual steering angle sensor 141, and rear wheel actual steering angle sensor 142 are configured by a digital computer. It is input to the calculation means. In the calculation means, first, the target behavior amount calculation means 20 calculates the target vehicle body slip angle β, which is the target behavior amount of the vehicle, according to a recurrence formula obtained by discretizing equations (12) and (13).
. and the target yaw angular velocity R8 are calculated. In addition, the target steering control amount calculation means 20 calculates the actual steering angles of the front and rear wheels necessary for changing the dynamic characteristics of the vehicle behavior to the dynamic characteristics that are easiest for the driver to maneuver, and calculates the front wheel target steering control amount signal δIT and the rear wheel target, respectively. As the steering control amount signal δrt (
14) to 19) are calculated according to a recurrence formula obtained by discretizing them. Note that the target behavior amount follows the dynamic characteristic that is easiest for this driver to maneuver, and the behavior amount matches the target behavior amount when there is no disturbance from the external environment such as a change in vehicle specifications or a crosswind disturbance. Next, the deviation calculating means 41 calculates the deviation between the target behavior amount and the actual measured value of the behavior amount caused by changes in vehicle specifications or disturbances from the external environment. Next, the correction amount calculating means 40 asymptotizes the deviation to zero and calculates the front wheel steering correction amount signal δfb1, the rear wheel steering correction amount signal δrb, and A suspension correction amount signal p is calculated. These correction amount signals allow the dynamic characteristics of the vehicle behavior to follow the target dynamic characteristics even when there are fluctuations in vehicle specifications or disturbances from the external environment. Since the suspension correction amount is used in addition to the steering correction amount, higher performance control characteristics can be obtained compared to the case where only the steering correction amount is used. Next, the steering control signal calculating means 70 adds the target steering control amount and the steering correction amount and outputs a steering control signal for achieving the target behavior amount. In addition, in the nonlinear compensation means 50, the correction amount calculation means 40
The suspension correction amount p for asymptoticing the obtained behavior amount to the target behavior amount is expressed as equation (11) and converted into the actual suspension correction amount λ, which is a control parameter for actual suspension system control. The actual suspension correction amount λ is a parameter that indicates which suspension on the front and rear wheels should offset the roll moment caused by turning. λ = 1 indicates that the roll moment is offset only with the front suspension, and λ = -1 indicates that the roll moment is offset with the front suspension only. λ=0 corresponds to canceling out only with the suspension, and canceling out equally between the front and rear wheels. In this way, in this embodiment, the actual control parameter λ is used as the suspension system correction amount calculated by the correction amount calculation means 40.
is not directly calculated, but a suspension correction amount p is calculated, and the nonlinear compensation means 50 converts this into an actual suspension correction amount λ. For this reason, the controlled object viewed from the correction amount calculation means 40,
That is, the steering correction amounts δ11, δ1. and suspension correction amount p
As input, the vehicle slip angle deviation β−β. And the system with yaw angular velocity deviation R-Re is x=[β-β. , R-RO]T-(27)u=[δ86
．． δrb+p]” ... (28) is linearly approximated as in equations (6), (9), and (zo), and by applying linear control theory, control is performed to asymptotize the deviation to zero. In addition, the target control amount calculation means 61 determines the target attitude in which the moment of force required to suppress roll due to turning and maintain the attitude is a feedforward attitude control amount. Controlled amount signal Mx (calculated by folding. Furthermore, the attitude control correction amount signal Mxb, which is a feedback attitude control amount, is
is calculated. Next, the attitude control amount calculation means 60 generates the target attitude control amount signal M! f and the attitude control correction amount signal M0 are added, and the moment of force required to maintain the attitude is calculated as the attitude control amount signal M, 6. Next, the suspension control signal calculation means 80 distributes the attitude control amount signal Mxo to the front and rear wheels according to the actual suspension correction amount λ, which is a control parameter for suspension system control, calculates the suspension control force of each wheel, and calculates the suspension control force as a suspension control signal. Output. As described above, a vehicle integrated control device for improving turning performance while maintaining the posture of the vehicle can be obtained. In addition, in this example, equations (12) and (13) were used as the vehicle behavior characteristics that are easiest for the driver to maneuver.
By setting the vehicle body slip angle to zero as in equation (12), the driver can safely operate the vehicle without worrying about spin. However, some drivers feel that the formula (12) has a significantly different characteristic than a normal 2WS vehicle, which makes it uncomfortable. In this case, instead of formula (12), the problem can be solved by making the characteristics of the vehicle slip angle proportional to the vehicle speed and following the steering with a first-order lag. Also, (13
) formula is set equal to that of a normal 2WS vehicle that exhibits low frequency gain of yaw angular velocity or neutral steering characteristics, so the driver can maneuver without feeling any discomfort, and the vehicle follows the steering with a first-order lag. Therefore, stable running is possible without overshoot. In this example, it is set to show a low frequency gain of yaw angular velocity or a neutral steer characteristic, but it is also possible to make it an oversteer characteristic or an understeer characteristic by setting the change in the low frequency gain depending on the vehicle speed. It is. By the way, this embodiment shows a vehicle integrated control device for a vehicle in which the steering angles of the front and rear wheels can be controlled. It can also be easily implemented for vehicles that can be controlled. In this case, the control target viewed from the correction amount calculation means is a linear system in which the steering correction amount and suspension correction amount for either the front or rear wheels are input. Further, in this embodiment, only attitude control regarding roll was considered, but attitude control regarding pitch may also be performed at the same time. In this case, the state quantity detection means is used to detect the pitch angle, the target attitude control amount calculation means is used to calculate the moment M of the force that suppresses the pitch movement due to acceleration and deceleration, and the attitude control correction amount calculation means is used to calculate the pitch angle. Ma calculates the moment Myb of the force that suppresses the pitch angle obtained from , and adds these moments of force to the attitude control amount calculation means. Therefore, in addition to the roll moment MXO and its front and rear wheel distribution λ, the suspension control signal calculation means needs to calculate the suspension control force that simultaneously realizes the pitch moment Myo. The calculation contents in the suspension control signal calculation means at this time are shown in the following equation. ... (29) ... (31) ... (32) Furthermore, when vibration suppression control is performed in addition to attitude control as suspension system control, the suspension control force necessary to suppress vibration is This can be realized by adding to equations (29) to 32). Although the above-described embodiment relates to an active suspension in which the suspension control force can be variably controlled, the present invention can also be applied to a vehicle in which only the roll stiffness of the front and rear wheels is variable. In this case, the suspension control drive means 8 calculates the roll stiffness of the front and rear wheels based on the actual suspension correction amount, and controls and drives the suspension mechanism by the suspension actuator based on the calculation result. That is, in this case, the roll stiffness of the front and rear wheels is Km+, respectively. to KmaX (
K2, ka<Km, , ) is assumed to be variable. At this time,
The suspension control drive means 8 is set, for example, according to the following equation so that the ratio of the roll stiffness of the front and rear wheels closely matches the actual suspension correction amount λ. However, K, , and are the roll stiffnesses of the front and rear wheels, respectively.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the structure of the present invention, Fig. 2 is a block diagram showing the structure of another invention, Fig. 3 and Fig. 3 are diagrams showing tire characteristics, and Fig. 5 is the structure of the embodiment. FIG. 1 ... Detection means 2 ... Target steering control amount calculation means 3 ... Target behavior amount calculation means 4 ... Correction amount calculation means 5 ... Nonlinear compensation means Steering control drive means Suspension control drive means

Claims (1)

[Scope of Claims] A detecting means for detecting at least a steering amount of a steering wheel and a behavior amount representing a turning motion of the vehicle, and a detection means for achieving a target behavior amount of the vehicle based on the detected steering amount. target steering control amount calculation means for calculating a target steering control amount; target behavior amount calculation means for calculating a target vehicle behavior amount based on the detected steering amount; correction amount calculation means for integrally calculating a suspension correction amount and a steering correction amount for correcting the calculated target steering control amount based on a linear model, and the calculated suspension correction amount; nonlinear compensation means for nonlinearly converting the amount of behavior based on the detected behavior amount and outputting an actual suspension correction amount representing the suspension characteristic; It is characterized by comprising a steering control drive means for producing an optimum steering angle on one side, and a suspension control drive means for variably controlling the suspension characteristics of each wheel according to the actual suspension correction amount and the attitude control amount. An integrated control device for vehicles.