JP3132145B2 - Vehicle suspension control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control system for a vehicle for controlling the wheel load of a vehicle according to the wheel speed of each wheel.

[0002]

2. Description of the Related Art A conventional vehicle suspension control device is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 2-3, which was previously proposed by the present applicant.
No. 511 (hereinafter, referred to as a first conventional example) and Shokai Sho 6
There is one described in Japanese Patent Application Laid-Open No. 2-191511 (hereinafter, referred to as a second conventional example).

In the first prior art, a suspension of four wheels of a vehicle is constituted by a fluid pressure cylinder interposed between a wheel side and a vehicle body side, and a fluid control valve for controlling a fluid supply amount to the fluid pressure cylinder. In a suspension device capable of changing the front and rear left and right wheel load moving amounts by controlling the fluid control valve, the rotational speed of each wheel is detected, and the rotational speed of the driven wheel is increased and the rotational speed of the non-driven wheel is increased. Increases, the proportional gain setting means reduces the ratio of the rear wheel roll moment to the front wheel roll moment,
By controlling the hydraulic cylinder of the suspension so that the rear wheel's load transfer amount during the turn is relatively smaller than that of the front wheel, sufficient lateral grip force of the rear wheel can be secured, and traveling during turning acceleration It improves stability.

The second conventional example has the same structure as the first conventional example, and detects the rotational speeds of the left and right driving wheels, respectively, to determine which of the left and right driving wheels is the high-speed driving wheel, ie, the slip. The control unit controls the hydraulic cylinder of the suspension corresponding to the high-speed drive wheel based on the detection result of the generated drive wheel, thereby increasing the vertical load of the drive wheel and increasing the vertical load on the road surface. This is to increase the driving force and improve the running stability.

[0005]

However, in such conventional vehicle suspensions, since the wheel load is controlled based only on the detected amount of the rotational speed of the wheels, the magnitude of the driving torque is influenced. An appropriate amount of force could not be generated in the actuator for each gear. That is, in the case of the first conventional example, for example, the steering characteristic when the drive slip occurs during the turning acceleration changes to the oversteer side as the gear position becomes the lower gear side position. Therefore, if the adjustment amount of the proportional gain adjusted based on the drive slip is set relatively small, while driving in a high-speed gear where the drive torque is small and the change in the steering characteristic is small,
Although the behavior due to inner wheel slip during turning acceleration can be prevented, steering stability during running in low-speed gears with large driving torque and large changes in steer characteristics is sufficiently secured because the adjustment amount of the proportional gain is too small. If the adjustment amount of the proportional gain is set to a relatively large value, on the other hand, during traveling in a low-speed gear where the driving torque is large and the change in the steering characteristic is large, the behavior due to the inner wheel slip during turning acceleration is prevented. However, the steering stability during running in a high-speed gear having a small driving torque and a small change in steering characteristics has a problem that the amount of adjustment of the proportional gain is too large and the vehicle is unnecessarily understeered.

In the case of the second conventional example, for example, if the amount of increase in the vertical load of the driving wheel in which slip occurs is set to a relatively small value, while the vehicle is running on a high-speed gear with a small driving torque, the driving wheel is not driven. Although it is possible to secure the driving force and prevent the behavior due to slip, while traveling in a low-speed gear having a large driving torque, the amount of increase in the vertical load is too small to sufficiently secure the driving force, Conversely, if the amount of increase in the vertical load is set relatively large, while traveling in a low-speed gear with a large driving torque, it is possible to secure the driving force on the road surface and prevent the behavior due to slip, but the driving torque is small. During traveling in a high-speed gear, the longitudinal load is merely increased more than necessary, and there is a problem that the posture of the vehicle changes due to the control for increasing the longitudinal load.

Accordingly, the present invention has been made in view of such a conventional problem, and provides a vehicle suspension control device capable of controlling the wheel load of a vehicle based on the gear position of a transmission device. With the goal.

[0008]

According to a first aspect of the present invention, there is provided a suspension control device for a vehicle which is disposed on at least one of a front wheel side and a rear wheel side. An actuator that generates a drag force against the roll of the vehicle body during traveling based on a predetermined roll rigidity, a wheel speed detecting unit that detects a wheel speed of each wheel, and a detection signal of the wheel speed detecting unit, and based on the input signal, If it is determined that the drive wheel is in a slip state, control is performed to adjust the roll distribution before and after the roll rigidity of the actuator in a direction to suppress a change in the steer characteristic of the vehicle due to the drive wheel slip. And a gear position determining means for determining a gear position of a transmission gear of the transmission device. A correction means for increasing the amount of adjustment of the longitudinal distribution of roll stiffness in a direction in which the control means suppresses the change in the steer characteristic as the determined gear position becomes the low-side position. Suspension device.

According to a second aspect of the present invention, a vehicle suspension control device is disposed between a vehicle body-side member and a wheel-side member swinging together with each wheel, and applies a vertical load to each wheel. An actuator, a wheel speed detecting means for detecting wheel speeds of left and right driving wheels, and a detection signal of the wheel speed detecting means, and an actuator for increasing a vertical load on a driving wheel having a faster wheel speed based on the input signals. A gear position determining means for determining a gear position of a transmission gear of a transmission device, and a gear position determined by the gear position determining means being shifted to a low side position. A correction means for increasing the vertical load on the drive wheel on the side of the higher wheel speed by the control means.

[0010]

According to the above construction, in the vehicle suspension control apparatus according to the first aspect of the present invention, the control means controls the adjustment amount of the front-rear distribution of the roll rigidity according to the gear position of the transmission gear of the transmission by the control means. The control is performed such that the position is increased as the position becomes closer to the low-speed gear side, so that a change in the steering characteristic of the vehicle due to the drive slip is suppressed.

Further, according to the present invention, the vehicle suspension control device according to the second aspect of the present invention determines the amount of increase in the longitudinal load of the driving wheel in which the slip occurs according to the gear position of the transmission gear of the transmission device. The control unit controls the gear position to be increased as the gear position becomes closer to the low-speed gear position, thereby increasing the driving force on the road surface and improving the running stability.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
4 to 4 show a first embodiment of the present invention.

FIG. 1 is a block diagram showing a first embodiment of the present invention. In the present embodiment, when it is determined that the driving wheel is in the slip state, the wheel speed difference between the driving wheel and the non-driving wheel is increased in order to suppress a change in the steering characteristic of the vehicle due to the driving slip. This is an example in which the present invention is applied to an active suspension that performs control to increase the roll stiffness gain on the front wheel side relative to the roll stiffness gain on the rear wheel side. FIG.
, 10FL to 10RR are front left to rear right wheels, 12
Indicates a wheel side member, 14 indicates a vehicle body side member, and 16 indicates an active suspension.

The active suspension 16 includes hydraulic cylinders 18FL to 18RR as actuators individually arranged between the vehicle body-side member 14 and each wheel-side member 12.
And pressure control valves 20FL to 20RR for adjusting the operating oil pressures of the hydraulic cylinders 18FL to 18RR, a hydraulic source 22 of the present hydraulic system, and the hydraulic source 22 and the pressure control valve 20F.
Accumulator 2 for pressure accumulation inserted between L and 20RR
4, 24, a lateral acceleration sensor 26 for detecting a lateral acceleration acting in the lateral direction of the vehicle body, and a front left to rear right wheel speed sensor (wheel speed detecting means) 27FL-2 for detecting a wheel speed of each wheel.
7RR, an engine speed sensor 28 for detecting the engine speed, and a controller 30 (control means) for individually controlling the output pressures of the pressure control valves 20FL to 20RR. The active type suspension 16 includes coil springs 36,..., 36 provided in parallel between the wheel side member 12 and the vehicle body side member 14 with respect to the hydraulic cylinders 18FL to 18RR, and the hydraulic cylinders 18FL to 18RR.
Throttle valve 3 individually communicated with pressure chamber L of 18RR described later.
2 and an accumulator 34 for absorbing vibration. Here, each coil spring 36 has a relatively low spring constant and supports a static load of the vehicle body.

Each of the hydraulic cylinders 18FL to 18RR has a cylinder tube 18a, in which an upper pressure chamber L closed by a piston 18c is formed. The upper end of the cylinder tube 18a is attached to the vehicle body-side member 14, and the piston rod 18
The lower end of b is attached to the wheel side member 12.

Each of the pressure control valves 20FL to 20RR has a valve housing having a spool slidably received in a cylindrical insertion hole, and a proportional solenoid provided integrally with the valve housing. It is formed in a pilot operation type. The supply port and the return port for the hydraulic oil of the pressure control valves 20FL to 20RR are hydraulic piping 3
The hydraulic oil supply 22 is communicated with the hydraulic oil supply side and the hydraulic oil return side of the hydraulic power source 22 via the valves 39, and the output port is communicated with each of the pressure chambers L of the hydraulic cylinders 18 FL to 18 RR via the hydraulic pipe 40.

[0017] Thus, by controlling the value of the exciting current i supplied to the proportional solenoid, the excitation current due to the thrust and the output port side of the control pressure on the basis of the P _C formed feedback pressure and the equilibrium is allowed to regulating pressure , hydraulic cylinders 18FL to control pressure P _C from the output port in response to the exciting current i
(〜18 RR) can be supplied to the pressure chamber L. The control pressure P _C, as shown in FIG. 2, and outputs the P _MIN when the exciting current i is close to zero, the exciting current i from this state is increased in the positive direction, an increase by a predetermined proportional gain K ₁ Then, when the pressure reaches the line pressure PMAX of the hydraulic pressure source 22, the pressure _becomes saturated.

As shown in FIG. 3, the lateral acceleration sensor 26 detects a lateral acceleration having a voltage value proportional to the lateral acceleration which becomes positive when the vehicle is steered to the right from a straight running state and becomes negative when the vehicle is steered to the left. The value Y _G is output.

As shown in the control block diagram of FIG. 4, the controller 30 detects the lateral acceleration detection value Y _G of the lateral acceleration sensor 26 and the wheel speed detection values W _{FL of} the front left to rear right wheel speed sensors 27FL to 27RR. W _RR and engine speed sensor 28
The engine speed detection value W _E are input. Among them, the front wheel side and rear wheel side variable gain adjusters 52F and 52R control the front wheel side and the rear wheel, which will be described later, according to the front left to rear right wheel speed detection values W _{FL to} W _RR and the engine speed detection value W _E. Wheel side roll stiffness gains K _F and K _R are calculated, and output voltages V _FL and V _RL obtained by multiplying the front wheel side and rear wheel side roll stiffness gains K _F and K _R by a lateral acceleration detection signal Y _G are output. The signs of the output voltages V _FL and V _RL are individually inverted by sign inverters 54F and 54R, and output voltages V _FR and V _RR are output. These output voltages V _{FL to} V _RR are individually applied to drive circuits 56FL to 56RR.
Is input to Here, the driving circuits 56FL to 56RR
Is constituted by, for example, a floating type constant voltage circuit, which converts the current into exciting currents i _{FL to} i _RR for the proportional solenoids of the respective pressure control valves 20FL to 20RR and outputs them.

Next, the control operation of the first embodiment will be described with reference to the flowchart of FIG.

First, in step S101, a lateral acceleration detection value Y _G , front left to rear right wheel speed detection values W _{FL to} W _RR , and an engine speed detection value W _E are read. In the following step S102, the front and rear wheel speed difference ΔN is calculated from the average value of the wheel speeds of the driving wheels and the non-driving wheels, and the process proceeds to step S103. In step S103 FIG. 6 (a), the determining gear position G _P from the relationship between the average value of the driving wheel speed engine rotation speed detection value W _E as shown in (b). 6A shows a case of a manual transmission vehicle, and FIG. 6B shows a case of an automatic transmission vehicle. Next, in step S104, an adjustment amount of the front wheel side distribution α of the roll stiffness gain is calculated based on the front and rear wheel speed difference ΔN in a control map optimized in advance by the gear position _GP as shown in FIG. In FIG. 7, the front wheel-side distribution α of the roll stiffness gain increases from the initial set value α ₀ with an increase in the front and rear wheel speed difference ΔN (here, α ₀ is set to, for example, 0.5). Furthermore, since the driving torque is larger during traveling in low-speed gears than in traveling in high-speed gears, the change in the steering characteristic during turning acceleration is large, so the amount of adjustment of the front wheel side distribution α of the roll rigidity gain must be set large. There is. Therefore, when the gear position _GP is equal to or lower than the second speed, the adjustment amount of the front wheel side distribution α is set to be larger with respect to the front and rear wheel speed difference ΔN than when the third gear or higher. Next, in step S105, the total gain K (= K _F) of the roll rigidity is added to the front wheel side distribution α.
+ K _R ) to calculate the front wheel side roll stiffness gain K _F ,
The rear wheel roll stiffness gain K _R is calculated by multiplying (1−α) by the total gain K.

Next, the process proceeds to step S106 to calculate the front left wheel pressure command value V _FL by multiplying the lateral acceleration detection signal Y _G by the front wheel roll rigidity gain K _F, and then proceeds to step S1.
At 07, the front right wheel side pressure command value _VFR is calculated by multiplying the front left wheel side pressure command value _VFL by (-1). In step S108, the rear wheel side roll stiffness gain K _{R is} added to the lateral acceleration detection signal Y _G.
Is multiplied to calculate the rear left wheel side pressure command value V _RL, and in the following step S109, the rear left wheel side pressure command value V _RL is multiplied by (−1) to calculate the rear right wheel side pressure command value V _RR . Then, in step S110, the pressure command values V _{FL to} V _RR are stored in the drive circuit 56F.
Output to L～56RR, at step S111, converts the pressure command value V _FL ~V _RR to the exciting current i _FL through i _RR for the proportional solenoid of the pressure control valve 20FL～20RR.

Accordingly, when the steering characteristic is going to change to the oversteer side due to the inner wheel slip at the time of turning acceleration, the front left to rear right wheel speed detection values W _{FL to} W _{RR are obtained.}
And determining a gear position G _P of the gear of the transmission device based on the engine rotational speed detection value W _E, increase the amount of adjustment of the front-wheel-side distribution α of roll stiffness gain during low-speed gear traveling, the front wheels during high-speed gear traveling in the opposite By reducing the adjustment amount of the distribution α, it is possible to optimally suppress the change in the steering characteristic of the vehicle due to the drive slip regardless of the gear position during the turning acceleration, thereby improving the turning characteristic of the vehicle. Can be. Next, FIG. 8 shows a flowchart of the second embodiment of the present invention. This embodiment is the same configuration and control block diagram as the first embodiment except that the front left and right wheel speed sensors W _FL and W _FR of the non-driving wheels are no longer necessary, and therefore the description thereof is omitted. .

In this embodiment, the amount of adjustment of the front wheel side distribution of the roll stiffness gain is calculated from the difference between the right and left wheel speeds of the driving wheels. The control operation will be described with reference to the flowchart of FIG. First, in step S201, the lateral acceleration detection signal Y
_G , the left and right wheel speed detection values W _RL and W _{RR of} the drive wheels and the engine speed detection value W _E are read. In the following step S202, the absolute value ΔN of the difference between the right and left wheel speeds of the driving wheels is calculated, and the process proceeds to step S203. Hereinafter, steps S203 to S211 perform the same control as steps S103 to S111 in the flowchart of the first embodiment of FIG.

According to the present embodiment, when the steering characteristic tends to change to the oversteer side due to the slip of the driving wheels during the turning acceleration, the rear right wheel speed detection value W _RL ,
The gear position _GP of the transmission gear of the transmission device is determined based on W _RR and the engine speed detection value W _E, and the adjustment amount of the front wheel side distribution α of the roll rigidity gain is increased during low-speed gear running, and conversely, during high-speed gear running. By reducing the adjustment amount of the front wheel side distribution α, during turning acceleration, the change in the steering characteristic of the vehicle due to the drive slip regardless of the gear position,
Since it can be optimally suppressed, the turning characteristics of the vehicle can be improved.

Although the first and second embodiments show examples in which the present invention is applied to an active suspension, the present invention is not limited to the active suspension, and is described in, for example, JP-A-63-57309. It may be applied to a variable stiffness stabilizer as described above.

Next, FIGS. 9 and 10 show a third embodiment of the present invention. In this embodiment, in order to prevent the behavior of one of the left and right driving wheels due to slip during traveling, the high-speed driving wheel, that is, the driving wheel in which the slip is generated, according to the increase in the difference between the left and right wheel speeds of the driving wheel. This is an example in which the present invention is applied to an active suspension that performs control to increase a vertical load and increase a driving force on a road surface, and has the same configuration as that of the second embodiment, and a description thereof will be omitted.

The control operation of the third embodiment will be described with reference to the flowchart of FIG. First, in step S301, left and right wheel speed detection values W _RL and W _RR of the driving wheels and an engine speed detection value W _E are read. In a succeeding step S302, the right and left wheel speed differences ΔN of the drive wheels are calculated, and the process proceeds to step S303. In step S303 FIG. 6 (a), the determining gear position G _P from the relationship between the average value of the driving wheel speed engine rotation speed detection value W _E as shown in (b). Next, in step S304, the longitudinal load increase amount ΔI is determined based on the difference between the left and right wheel speeds ΔN of the drive wheels using a control map that has been optimized based on the gear position _GP as shown in FIG. FIG.
Is set such that the vertical load increase amount ΔI is larger during traveling in a low-speed gear (second speed or lower) having a large driving torque than in traveling in a high-speed gear (third speed or higher). Next, in steps S305 to S308, the exciting currents i _{FL to} i _RR output to the proportional solenoids of the pressure control valves 20FL to 20RR of each wheel are increased from the neutral pressure command values i _{FL0 to} i _RR0 by the vertical load increase ΔI. Then, the excitation currents i _{FL to} i _RR are output in step S309.

Therefore, during the straight running acceleration, when one of the right and left driving wheels slips, the slip is determined according to the difference between the left and right wheel speeds of the driving wheels and the gear position of the transmission gear of the transmission device. By increasing the amount of increase in the vertical load of the drive wheel where the turbulence occurs, the behavior is prevented and the driving force on the road surface is increased, whereby the acceleration performance of the vehicle can be improved. In addition, the acceleration performance on the split μ road is also improved.

In the above embodiments, the gear position _GP is determined from the relationship between the engine speed and the average value of the front and rear wheel speeds or the drive wheel speeds. However, the present invention is not limited to this. Alternatively, the determination may be made from the position of the shift lever.

Although FIGS. 7 and 10 show examples of control using two types of control maps, different control maps may be set for all gear positions.

[0032]

As described above, according to the present invention,
In the vehicle suspension control device according to the first aspect, the adjustment amount of the front-rear distribution of the roll stiffness is adjusted according to the gear position of the transmission gear of the transmission device, that is, the drive torque, so that the adjustment amount increases as the gear position becomes the lower gear position. As a result, a drive slip occurred on the turning inner wheel during turning acceleration,
The change of the steering characteristic to the oversteer side can be optimally suppressed regardless of the gear position.

According to a second aspect of the present invention, there is provided a vehicle suspension control apparatus for controlling an increase amount of a vertical load on a high-speed driving wheel according to a gear position of a transmission gear of a transmission device, that is, a driving torque. Is adjusted so as to become larger as the position becomes closer to the low-speed gear side. Therefore, irrespective of the gear position, the driving force can be sufficiently secured on the road surface, the behavior of the vehicle can be prevented, and the acceleration performance can be improved. In particular, on a split μ road, the acceleration performance can be significantly improved.

[Brief description of the drawings]

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

FIG. 2 is an output characteristic diagram of a pressure control valve applicable to the present invention.

FIG. 3 is an output characteristic diagram of a lateral acceleration sensor applicable to the present invention.

FIG. 4 is a control block diagram showing a configuration of a controller according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing a control operation of the controller according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a function for determining a gear position.

FIG. 7 is a diagram showing a control map of front wheel side distribution of wheel speed-roll stiffness gain optimized for each gear position.

FIG. 8 is a flowchart showing a control operation of a controller according to a second embodiment of the present invention.

FIG. 9 is a flowchart illustrating a control operation of a controller according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a wheel speed-longitudinal load control map optimized for each gear position.

[Explanation of symbols]

10FL to 10RR Wheels 12 Wheel side members 14 Body side members 16 Active suspensions 18FL to 18RR Hydraulic cylinders (actuators) 20FL to 20RR Pressure control valves 26 Lateral acceleration sensors 27FL to 27RR Front left to rear right wheel speed sensors (wheel speed detecting means 28) engine speed sensor 30 controller (control means) 50F front wheel side variable gain adjuster 50R rear wheel side variable gain adjuster 52FL-52RR drive circuit 53F, 53R sign inverter

Claims (2)

(57) [Claims] An actuator disposed on at least one of a front wheel side and a rear wheel side to generate a drag force against a roll of a vehicle body during turning based on a predetermined roll rigidity, and a wheel speed detecting a wheel speed of each wheel. Detecting means for inputting a detection signal of the wheel speed detecting means, and when it is determined based on the detection signal that the driving wheel is in a slip state, suppresses a change in the steering characteristic of the vehicle due to the driving wheel slip. A control unit for performing roll control by adjusting the front and rear distribution of roll rigidity of the actuator in the direction in which the actuator is driven, a gear position determining unit for determining a gear position of a transmission gear of the transmission device; As the gear position determined by the gear position determining means becomes the low side position, the control means controls the roll in a direction in which the steering characteristic change is suppressed. A vehicle suspension device comprising: a correcting unit that increases an adjustment amount of the front-rear distribution of the rigidity. 2. An actuator disposed between a vehicle body-side member and a wheel-side member swinging together with each wheel to apply a vertical load to each wheel, and wheel speed detecting means for detecting wheel speeds of left and right drive wheels. And a control means for inputting a detection signal of the wheel speed detection means and controlling an actuator based on the detection signal to increase the vertical load on the drive wheel on the fast wheel side. Gear position determining means for determining the gear position of the transmission gear; and, as the gear position determined by the gear position determining means becomes the low side position, the control means controls the vertical load of the drive wheel with the higher wheel speed. A suspension control device for a vehicle, comprising a correction means for increasing the increase amount.