JPH05185815A - Road state judger for vehicle - Google Patents

Abstract

PURPOSE:To make the judgment of a road state to be performed yet more properly or positively in regard to a road state judger for a vehicles suitable in use on rolling and steering control over a car in a car active suspension system. CONSTITUTION:This road state judger is provided with a first judging means 82A, so judging that a road surface is liable to slip at a time when the value of actual lateral acceleration is larger as much as the specified value than that of the calculated lateral acceleration, and a second judging means 82B, so judging that the road surface is liable to slip at a time when a size of steering assisted force is smaller than that of a steering angle, and in this constitution, when it is so judged that the road surface is in a state of being apt to slip at either of the first judging means 82A or the second judging means 82B, it is determined that the road surface is in a state of being easily slipped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle road surface condition determination device, and more particularly to a vehicle road surface condition determination device suitable for use in vehicle roll control and steering control in an active vehicle suspension system.

[0002]

2. Description of the Related Art In vehicles such as automobiles, there is a demand for controlling the characteristics of the vehicle according to the road surface condition. That is, depending on whether the road surface is slippery or not, for example, control of the vehicle active suspension device, drive force distribution control of a four-wheel drive vehicle, steering distribution control of each wheel of a four-wheel steering vehicle, etc. can be controlled. There is a request that.

As a conventional means for determining such a road surface state, for example, one utilizing a calculated lateral acceleration disclosed in Japanese Patent Laid-Open No. 60-148769 is known.

[0004]

By the way, it is difficult for the conventional road surface condition determining means to always properly judge whether or not the road surface is slippery, so that the road surface condition can be judged more appropriately or surely. I want to The present invention is
The present invention has been made in view of the above problems, and an object of the present invention is to provide a road surface state detecting device for a vehicle, which can determine a road surface state more appropriately or reliably.

[0005]

For this reason, the vehicle road surface state detecting device according to claim 1 of the present invention is a vehicle equipped with a power steering system for exerting a steering assist force in accordance with a steering reaction force. Vehicle speed detection means for detecting the vehicle steering angle, steering angle detection means for detecting the steering angle of the vehicle, lateral acceleration detection means for detecting the lateral acceleration applied to the vehicle, and steering assist force for detecting the steering assist force of the power steering. A detection means, a lateral acceleration calculation means for calculating a lateral acceleration that should occur in the vehicle based on the vehicle speed detected by the vehicle speed detection means and the steering angle detected by the steering angle detection means;
By comparing the actual lateral acceleration value detected by the lateral acceleration detecting means with the calculated lateral acceleration value calculated by the lateral acceleration calculating means, the actual lateral acceleration value is higher than the calculated lateral acceleration value. A first judging means for judging that the road surface is in a slippery state when it is larger than a certain amount, and a steering assist detected by the steering assist force detecting means with respect to the magnitude of the steering angle detected by the steering angle detecting means. A second judging means for judging that the road surface is in a slippery state when the magnitude of the force is smaller than a required amount is provided, and either one of the first judging means and the second judging means described above It is characterized in that when it is determined that the road surface is slippery, the road surface is determined to be in a slippery state.

According to a second aspect of the present invention, there is provided a vehicle road surface state detecting device for detecting a vehicle speed of a vehicle in a vehicle equipped with a power steering system for exerting a steering assist force according to a steering reaction force. Steering angle detecting means for detecting a steering angle of the vehicle, lateral acceleration detecting means for detecting a lateral acceleration applied to the vehicle, steering assist force detecting means for detecting a steering assist force of the power steering, and vehicle speed detection A lateral acceleration calculating means for calculating a lateral acceleration that should occur in the vehicle based on the vehicle speed detected by the means and the steering angle detected by the steering angle detecting means; and an actual lateral acceleration detected by the lateral acceleration detecting means. The value of the acceleration is compared with the value of the calculated lateral acceleration calculated by the lateral acceleration calculating means, and when the actual value of the lateral acceleration is larger than the calculated lateral acceleration by a predetermined amount or more, the road surface slips. The first judging means for judging that the steering assist force is in a non-operating state, and the magnitude of the steering assist force detected by the steering assist force detecting means with respect to the magnitude of the steering angle detected by the steering angle detecting means. And a second judging means for judging that the road surface is in a slippery state when both are smaller than the above, both of the first judging means and the second judging means judges that the road surface is in a slippery state. It is characterized in that it is configured to determine that the road surface is in a slippery state when it is done.

[0007]

In the vehicle road surface state detecting device according to claim 1 of the present invention described above, the first judging means calculates the actual lateral acceleration value detected by the lateral acceleration detecting means and the lateral acceleration calculating means. The second determination means compares the calculated lateral acceleration value with the actual lateral acceleration value and determines that the road surface is slippery when the actual lateral acceleration value is larger than the calculated lateral acceleration value by a predetermined amount or more.
When the magnitude of the steering assist force detected by the steering assist force detecting means is smaller than the required amount with respect to the magnitude of the steering angle detected by the steering angle detecting means, it is determined that the road surface is slippery. Then, when it is determined that the road surface is in a slippery state by any one of the first determination means and the second determination means, it is determined that the road surface is in a slippery state.

In the vehicle road surface state detecting device according to claim 2 of the present invention described above, the first determining means calculates the actual lateral acceleration value detected by the lateral acceleration detecting means and the lateral acceleration calculating means. The second determination means compares the calculated lateral acceleration value with the actual lateral acceleration value and determines that the road surface is slippery when the actual lateral acceleration value is larger than the calculated lateral acceleration value by a predetermined amount or more. When the magnitude of the steering assist force detected by the steering assist force detector is smaller than the required amount with respect to the magnitude of the steering angle detected by the detector, it is determined that the road surface is slippery. Then, when both the first determining means and the second determining means described above determine that the road surface is slippery, it is determined that the road surface is slippery.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle road surface condition determining apparatus as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a roll control system (OS / US control) of an active suspension apparatus for a vehicle equipped with this determining apparatus. FIG. 2 is a schematic configuration diagram showing the mechanism of the apparatus, FIG. 3 is a block diagram showing the overall configuration of the control system, and FIGS. 12 is a control gain map according to the present invention, FIG. 12 is a determination map regarding road surface condition determination, and FIG. 13 is a schematic configuration diagram schematically showing a part related to low μ road control of the roll control system (including OS / US control system), FIG. 14 is a flowchart relating to low μ road control of the roll control system (including the OS / US control system), FIG. 15 is a characteristic diagram of the roll control amount, FIG. 16 is a characteristic diagram of the roll state of the vehicle body, and FIG. The figure which compares the characteristic of each control gain which changes with a steering angle, FIG. 18 is the figure which compares the characteristic of each control gain which changes with a vehicle speed, and FIGS. 19-21 is all with the modification of the road surface state determination apparatus for vehicles. A flow chart showing a modified example of the low μ road control of the roll control system (including the OS / US control system), FIG. 22 is a graph for explaining the phase correction of the data to be carried out for the road surface condition judgment, and FIG. 23 is for the road surface condition judgment. It is such a determination map.

This embodiment describes a vehicle active suspension device equipped with a vehicle road surface condition determining device of the present invention. This vehicle active suspension device operates its actuator hydraulically.
It has a hydraulic active suspension system. FIG. 2 is a configuration diagram of the hydraulic system. In FIG.
The oil pump 1 is provided so as to suck the oil stored in the reserve tank 3 through the oil passage 2 and discharge the oil to the supply oil passage 4. Oil pump 1 for oil supply passage 4
In the vicinity, accumulators 5 and 6 for absorbing the pulsation of the discharge hydraulic pressure by the oil pump 1 are connected in series, and the accumulators 5 and 6 have different set frequencies. Further, oil filters 7 and 8 are connected to the downstream side of the accumulator 6, and a relief oil passage 10 and a pilot relief oil passage 9 are connected to the downstream side of the oil filter 8.

The pilot relief oil passage 9 is connected to a solenoid valve 11, and the solenoid valve 11 is
The discharge oil passage 12 communicating with the reserve tank 3 is selectively communicated with a return oil passage 13 of a control valve or a pilot relief oil passage 9 which will be described later. An operation check valve 14, which operates by receiving the pressure in the pilot relief oil passage 9 as pilot pressure, is provided upstream of the solenoid valve 11 in the return oil passage 13. When the discharge oil passage 12 is in communication with the discharge oil passage 12, the vehicle height is maintained by blocking the discharge oil passage to prevent the discharge of oil, while the return oil passage 13 and the discharge oil passage 1 are held.
When the two are communicated with each other, they are opened to allow oil to be discharged, thereby enabling suspension control described later.

The relief oil passage 10 is connected to the discharge oil passage 12 on the downstream side of the solenoid valve 11, and a relief valve 15 is provided in the middle of the relief oil passage 10. When the upstream hydraulic pressure of the relief valve 15 becomes equal to or higher than a predetermined pressure, the oil discharged from the oil pump 1 is discharged to the reserve tank 3 side.
Furthermore, the relief valve 15 receives the pilot pressure from the pilot relief oil passage 9, and the set pressure changes depending on the state of the solenoid valve 11 that changes the pressure in the pilot relief oil passage 9. When the vehicle height is maintained so that the oil passage 9 and the discharge oil passage 12 are communicated with each other, the set pressure is reduced and the load on the pump 1 is reduced.

An oil cooler 16 is provided in the discharge oil passage 12.
Further, the oil filter 17 is interposed in series, and a relief valve 18 is provided in parallel with the oil filter 17 for compensation when the oil filter 17 is clogged. Further, the supply oil passage 4 is branched to a front wheel side oil passage 4F and a rear wheel side oil passage 4R at a downstream side of a branch portion with the relief oil passage 10, and line pressures are respectively applied to the oil passages 4F and 4R. Accumulators 19F and 19R for holding and check valve 20
F and 20R are interposed, and each check valve prohibits the flow of oil from the downstream side to the upstream side. An oil filter 21 is provided upstream of the accumulator 19R in the rear wheel side oil passage 4R. The oil passages 4F and 4R have check valves 20F and 20F, respectively.
On the downstream side of R, an oil passage is branched for each wheel, and suspension units 22FL, 22FR, 22RL, 22RR provided for each wheel are connected to each oil passage. In addition, each suspension unit 22FL,
22FR, 22RL, 22RR are check valves 23FL, 2 for prohibiting the flow of oil from the downstream side to the upstream side.
Return oil passage 13 through 3FR, 23RL, 23RR
Check valve 23F on the front wheel side
The upstream sides of the L and 23FR are communicated with each other via the throttle 24F,
A throttle 2 is attached to the check valves 23RL and 23RR on the rear wheel side.
4RL and 24RR are provided in parallel. The throttles 24F, 24RL, 24RR are provided to average the internal pressures of the actuators of the wheels when the vehicle height is maintained as described above.

An accumulator 25 for preventing pulsation of the return oil passage is provided in the rear wheel return oil passage 13R.
Is provided between the return oil passage 4R on the rear wheel side and the supply oil passage 13R on the rear wheel side, and a relief valve 26 for preventing high pressure in the return oil passage and a cock 27 for maintenance. Are provided in parallel. Since each suspension unit has the same structure, the suspension unit 22FL for the left front wheel will be described. A single-acting hydraulic actuator 30 is provided between the vehicle body and the wheels in parallel with a suspension spring (not shown). Oil passage 3 communicating with the hydraulic chamber of the hydraulic actuator 30
1 and the oil supply passage 4F and the oil discharge passage 13F through the control valve 32 interposed between the hydraulic actuator 1
The supply and discharge of hydraulic pressure to and from the hydraulic chamber 4 is controlled. A proportional solenoid valve is used as the control valve 32, and the hydraulic actuator 1 is proportional to the supply current by controlling the valve opening according to the supplied current.
The pressure in 4 can be controlled. An oil passage 32 is also connected to the hydraulic actuator 30, and the oil leaking from the hydraulic chamber is sent to the discharge oil passage 12.

An accumulator 34 is connected to an oil passage 31 communicating with the hydraulic chamber of the hydraulic actuator 30 via a throttle 33. The throttle 33 exerts a vibration damping effect and is enclosed in the accumulator 34. The gas spring exerts a gas spring action. Further, a damping force control valve 35 is provided in parallel with the throttle 33, and the damping force can be set softly by driving the damping force control valve 35 to the open position. Further, the oil passage 31 is provided with a pressure sensor 36 for detecting the internal pressure of the hydraulic actuator 30.

The operation of each control valve 32, each damping force control valve 33, and solenoid valve 11 is controlled by a controller 40 composed of a microcomputer.
When it is necessary to control the operating state of the hydraulic actuator 30, the return oil passage 13 and the discharge oil passage 1 are changed from the state shown in FIG.
2 is allowed to discharge oil from the hydraulic actuator 30, and when it is not necessary to control the operating state of the hydraulic actuator 30 such as during parking, the hydraulic actuator 30 is switched to the state shown in FIG.
The vehicle height is maintained by prohibiting the discharge of oil from the vehicle.

The controller 40, as shown in FIG.
In addition to the detection output of the pressure sensor 36 described above, a detection output from a lateral G sensor 41 that detects the lateral acceleration acting on the vehicle body, and a steering angle sensor 42 that detects the steering angle of the steering wheel.
Speed sensor 43 that detects the detection output of the vehicle and the traveling speed of the vehicle
Detection output, a front-rear G sensor 44 detection output for detecting longitudinal acceleration acting on the vehicle body, a brake switch 45 detection output for detecting a brake pedal operation, and a throttle sensor 46 detection for an engine throttle opening. Output, detection output of a stroke sensor 47 that detects the vertical stroke state of each wheel, detection output of a vertical G sensor 48 that is provided for each wheel and that detects vertical acceleration that acts on the vehicle body, and the state of the road surface in front of the vehicle. The detection outputs of the preview sensor 49 are input, and the controller 40 controls the operating states of the control valve 32 and the damping force switching valve 35 for each wheel based on the detection outputs of these sensors. It has become.

The schematic construction of the controller 40 is shown in the control block diagram of FIG. As shown in FIG. 3, in the controller 40, a control unit (steering control unit) 40A for adjusting the steering stability of the vehicle and a control unit (attitude control unit) 40B for adjusting the posture of the vehicle. And a control unit (vehicle height control unit) 55 for adjusting the vehicle height of the vehicle,
A control unit (ride comfort control unit) 40C for adjusting the ride comfort of the vehicle is provided.

The operation control unit 40A includes an anti-roll control unit 50 and an OS / US control unit (steer control unit) 51.
The posture control unit 40B includes an anti-pitch control unit 52, and the riding comfort control unit 40C includes a composite control unit 56 and a preview control unit 59. The anti-roll controller 50 includes a pressure sensor 36, a lateral G sensor 41,
The detection outputs of the steering angle sensor 42, the vehicle speed sensor 43, and the front-rear G sensor 44 are input, and a control amount for supporting the load movement amount during steering and suppressing a posture change in the roll direction of the vehicle body is output. It has become. The details of the anti-roll control unit 50 will be described later.

Further, the US / OS control section 51 receives the detection outputs of the steering angle sensor 42 and the vehicle speed sensor 43,
A control amount for controlling the vehicle body steer characteristic is output by increasing or decreasing the roll rigidity ratio between the front and rear wheels based on the steering angular velocity calculated from the output of the steering angle sensor 42 and the vehicle speed. That is, this US / OS control unit 5
1 is configured to be combined with the anti-roll control unit 50.

In the anti-pitch control section 52, the vehicle speed sensor 43, the longitudinal G sensor 44, the brake switch 4
5, and the detection output of the throttle sensor 46 is input,
Based on the output of the front / rear G sensor 44, a control amount for supporting the load movement amount during acceleration / deceleration and suppressing the posture change of the vehicle body in the pitching direction is output. The gain is supposed to increase.

Further, in the vehicle height control unit 55, the detection outputs of the vehicle speed sensor 43 and the stroke sensor 47 are inputted, and the control for obtaining the target vehicle height corresponding to the vehicle speed by the integral control based on the detection outputs of the stroke sensor 47. The quantity is designed to be output. Furthermore, the composite control unit 56
Although not shown in the figure, a skyhook damper control unit and a mass increase control unit are provided.

In the skyhook damper control section, the steering angle sensor 42, the vehicle speed sensor 43, the brake switch 4
5, the detection outputs of the throttle sensor 46 and the vertical G sensor 48 are input, and control is performed to suppress the fluffy feeling of the vehicle body by reducing the absolute sprung speed calculated from the detection output of the vertical G sensor 48. During sudden steering, high speed, braking, and acceleration, the gain relative to the absolute vertical speed is increased.

In the mass increase control section, the vehicle speed sensor 43, the stroke sensor 47 and the vertical G sensor 4
The detection output of 8 is input, and the control amount for suppressing the sprung acceleration and reducing the vibration transmission force is output. In addition to this, the riding comfort control section 40C is adapted to output a control amount for reverse spring control for reducing the spring constant to reduce the vibration transmission force during a minute stroke.

Although not shown, a stroke damper control section is also provided. In this stroke damper control section, the steering angle sensor 42, the brake switch 45, and the throttle sensor 4 are provided.
6, and the detection output of the stroke sensor 47 is input,
The control for reducing the stroke speed calculated from the detection output of the stroke sensor 47 to attenuate the vehicle body vibration is performed, and the gain with respect to the stroke speed is increased especially at the time of sudden steering, braking and acceleration.

The control amounts output from the control units 50 to 56 are input to the adder 57 for each wheel, and the adder 5
The total control amount added in 7 is input to the drive circuit 58. Then, the drive circuit 58 outputs a current corresponding to the input control amount to the control valve 32 to perform active control of the operation of the hydraulic actuator 30, thereby realizing control in which the posture change is small and a good ride comfort is obtained. It Further, the detection output of the pressure sensor 36 is input to the drive circuit 58, and constant pressure control for feedback control is performed so that the internal pressure of the hydraulic actuator 30 becomes a target control pressure (output of the adder 57).

In the preview controller 59,
When the detection outputs of the vehicle speed sensor 43 and the preview sensor 49 are input and it is detected from the outputs of the preview sensor 49 that there is a protrusion or a step ahead of the vehicle, the time when the wheel passes through the protrusion or the step is calculated in relation to the vehicle speed. The damping force switching valve 3 when passing through a protrusion or a step
By outputting a control signal to the drive circuit 60 so as to bring the opening 5 into the open state, the vibration transmission at the time of passing over the protrusion is reduced.

This active suspension device for a vehicle has a roll control amount and OS / OS depending on the road surface condition.
Means are provided to correct the US controlled variable. FIG. 13 schematically shows these road surface correspondence correcting means. In FIG. 13, reference numeral 82 is a road surface condition determination unit (road surface condition determination unit) that determines whether the traveling road surface is a low μ road (slippery road surface), and 50A is a main portion of the anti-roll control unit. 51A is a main part of the OS / US control unit (steer control unit).

Reference numeral 142 is a low μ value from the road surface condition determining section 82.
When the road information is received, the roll control correction unit performs a road surface state correspondence correction (low μ road correction) on the roll control amount and outputs it as a roll control gain K _R. When the low μ road information is received from the road surface condition determination unit 82, the OS 143 performs road surface condition corresponding correction (low μ road correction) on the distribution ratio α ′ as the OS / US control amount, and outputs it as the distribution ratio α. / US correction unit for control.

Reference numeral 87 is a control amount calculation unit, which calculates each wheel [right front wheel (FR), left front wheel (FL), right rear wheel (RR), from the roll control gain K _R and the distribution rate α. Left rear wheel (RL)] roll control amount (roll control gain)
Is calculated and output. As shown in FIG. 1, the anti-roll control unit 50 as described above is a road surface correspondence correction unit.
The details of the anti-roll control unit 50 will be described together with the road surface correspondence correcting means.

In FIG. 1, the actual lateral acceleration signal G _Y detected by the lateral G sensor 41 is input to the lateral G gain setter 61, and the control gain K corresponding to the lateral acceleration G _Y is based on the map shown in FIG. _G times. Horizontal G gain setting device 61
The gain K _G set in is gradually decreased in a region where the lateral acceleration G _Y is considerably large, and the roll amount is increased during a high G turn to warn the driver of a dangerous state. ..

The output of the lateral G gain setting device 61 is input to the steering angular velocity gain setting device 62 and multiplied by Kθ '. The control gain Kθ ′ in the steering angular velocity gain setter 62 is
The steering angle signal θ detected by the steering angle sensor 42 is variably set as shown in FIG. 5 by the steering angular velocity signal θ ′ obtained by differentiating the steering angle signal θ by the differentiator 63. That is, the steering angular velocity θ ′
The control gain Kθ 'remains constant until the control gain Kθ' reaches a predetermined value. However, when the control gain Kθ 'exceeds the predetermined value, the control gain Kθ' decreases with an increase in the steering angular velocity θ '. 'Is set to be constant. As a result, the gain of the roll control amount with respect to the actual lateral acceleration signal G _Y is reduced in a region where the steering angular velocity θ'in which the phase delay in the generation of the actual lateral acceleration G _{Y with} respect to the steering operation becomes large is large.

The output of the steering angular velocity setting device 62 is input to the vehicle speed gain setting device 64 and multiplied by K _V. The control gain K _V in the vehicle speed gain setter 64 is variably set as shown in FIG. 6 by the vehicle speed signal V detected by the vehicle speed sensor 43. That is, the control gain K _V is constant until the vehicle speed V reaches a predetermined value, but when the vehicle speed V exceeds the predetermined value, the control gain K _V decreases with an increase in the vehicle speed V, and when it exceeds a certain vehicle speed V thereafter, the control gain K _V again. _V is set to be constant. As a result, the gain of the roll control amount with respect to the actual lateral acceleration signal G _Y is reduced during high-speed traveling in which the phase delay in the generation of the actual lateral acceleration G _{Y with} respect to the steering operation becomes large.

The load gain setter 65 provided at the subsequent stage of the vehicle speed gain setter 64 multiplies the output of the vehicle speed gain setter 64 by K _L , and corresponds to the increase ΔL of the load acting on the wheels. As shown in FIG. 7, the control gain K _L is variably set. That is, a compensates that easily roll occurs load shift amount when the roll is increased at the time of load increase by increasing the control gain K _L with increasing load.

The load increase amount signal ΔL input to the load gain setting unit 65 is calculated by the load change calculating unit 66 based on the detection outputs of the steering angle sensor 42, the vehicle speed sensor 43, the pressure sensor 36, and the longitudinal G sensor 44. The load increase amount ΔL that is detected is calculated through the process shown in the flowchart of FIG. That is, the steering angle θ is 10 ° or less, the longitudinal acceleration G _X is 0.15 G or less, and the vehicle speed is 20.
When it is Km / h or less, the outputs P of the left and right pressure sensors are averaged and the reference value P _O is subtracted from the average value P _A, so that the load increase amount ΔL is obtained. Therefore, the load increase amount ΔL is independently calculated for the front wheels and the rear wheels.

On the other hand, the calculated lateral acceleration calculation unit 67 receives the detection signal θ of the steering angle sensor 42 and the detection signal V of the vehicle speed sensor 43, and calculates the calculated lateral acceleration G _YB by the following calculation formula. G _YB = V ² θ / (1 + AV ² ) LΡ where A: Stability factor L; Wheelbase Ρ; Steering gear ratio Calculated lateral acceleration G calculated by the calculated lateral acceleration calculator 67
_YB is input to the lateral G'gain setter 68 and multiplied by K _GB . Control gain K in lateral G'gain setter 68
_GB is variably set according to the rate of change (differential value) G _YB ′ of the calculated lateral acceleration obtained by differentiating the calculated lateral acceleration G _YB by the differentiator 69, as shown in FIG. That is, the control gain K _GB is 0 until the calculated lateral acceleration change rate (differential value) G _YB ′ reaches a predetermined value, but when it exceeds the predetermined value, the calculated lateral acceleration change rate (differential value) G _YB ′. Control gain K _GB
Is increasing. Thus, when the rate of change (differential value) G _YB ′ in the calculated lateral acceleration having an output phase faster than the calculated lateral acceleration G _YB is large, the control gain for the calculated lateral acceleration G _YB faster than the actual lateral acceleration G _Y is increased. The control amount corresponding to the calculated lateral acceleration G _YB can be quickly output when a sudden occurrence of lateral G is predicted.

The output of the lateral G'gain setter 68 is supplied in parallel to the steering angular velocity gain setter 70 and the vehicle speed gain setter 71, respectively. The control gain Kθ _B ′ in the steering angular velocity gain setting device 70 is variably set as shown in FIG. 9 by the steering angular velocity signal θ ′ obtained from the differentiator 63, and the steering angular velocity gain setting device 70 outputs the lateral G ′ gain setting device 68. Is multiplied by Kθ _B ′. In other words, 'with an increase in, K [theta _B' steering angular velocity theta from the region is 0, the area K [theta _B 'is steering angular velocity theta' increases with, K [theta _B 'through a region where a constant value, the steering angular velocity theta' K with increasing
It shifts to a region where θ _B ′ decreases. As a result, the control gain for the calculated lateral acceleration G _YB at the time of sudden steering is increased, and the effect of suppressing the initial roll can be improved.
At the time of super steer steering in which the generation of the actual lateral G is significantly delayed, the control gain for the calculated lateral acceleration G _YB can be reduced to maintain the balance with the control corresponding to the actual lateral G.

The control gain K _VB in the vehicle speed gain setter 71 is the vehicle speed signal V detected by the vehicle speed sensor 43.
Is variably set as shown in FIG.
At 1, the output of the lateral G'gain setter 68 is multiplied by K _VB .
That is, as the vehicle speed V increases, the area where K _VB is 0, the area where K _VB increases with the vehicle speed V, the area where K _VB becomes a constant value, the area where K _VB decreases with the increase of vehicle speed V. It is supposed to move to. As a result, the control gain for the calculated lateral acceleration G _YB is increased in the region where a phase delay easily occurs in the actual lateral G generation, the effect of suppressing the initial roll can be improved, and the calculation is performed at ultra-high speed in which the actual lateral G generation is significantly delayed. Decrease the control gain for lateral acceleration G _YB to reduce the actual lateral G
The balance with the control corresponding to can be maintained.

The outputs of the steering angular velocity gain setting device 70 and the vehicle speed gain setting device 71 are input to the adder 72 and added, and then input to the load gain setting device 73. Adder 72
Is output to the load gain setter 73 and multiplied by K _LB. The load gain setter 73 is the load change calculator 66 described above.
The control gain K _LB is variably set as shown in FIG. 11 in accordance with the increased load ΔL input from. That is, by decreasing the control gain K _LB as the load increases, the phase of the actual lateral acceleration is delayed when the load increases, and the phase difference between the control corresponding to the actual lateral acceleration G _Y and the control corresponding to the calculated lateral acceleration G _YB. Is to prevent the control from becoming unbalanced.

Then, the output of the load gain setting unit 65 and the output of the load gain setting unit 73 are added by the adder 74 and output as the roll control amount to the adder 57 in FIG. .. The roll control amount output from the adder 74 is set such that the internal pressure of the hydraulic actuator 30 increases for the wheel on the same side as the direction in which the occurrence of lateral G is detected or predicted, and the lateral G occurs. For the wheels on the opposite side to the direction in which is detected or predicted, each control valve 32 is driven in the direction in which the internal pressure of the hydraulic actuator 30 decreases, and the control amount is to suppress the roll generated in the vehicle body.

Further, the road surface correspondence correction means for the roll control amount incorporated in the anti-roll control section 50 will be described. This correction means is provided by the calculation lateral acceleration calculation unit 6
The phase delay unit 81 for delaying the phase of the calculated lateral acceleration G _YB calculated in 7 and a low μ road (slippery road surface)
Road condition determination unit 82, a correction gain setting unit 83 that sets a correction gain Kμ ₁ corresponding to this road surface condition, and a roll control amount output from the adder 74. It is also provided with a road surface condition corresponding correction unit 84 that integrates ₁ .

The phase delay unit 81 delays the phase of the calculated lateral acceleration G _YB calculated by the calculated lateral acceleration calculation unit 67 by a predetermined amount β and outputs the delayed signal. For example, a low-pass filter (1 at a cutoff frequency of 5 Hz is used). Next low-pass filter, etc.). This is because the vehicle behavior is delayed with respect to the steering, so that a time difference occurs between the calculated lateral acceleration G _YB and the actual lateral acceleration G _{Y as} shown in, for example, FIG. If the levels of G _YB and actual lateral acceleration G _Y are compared, accurate road surface determination cannot be performed.
Therefore, the phase delay is performed in this way. This phase delay process eliminates the time difference between the lateral acceleration G _YB and the actual lateral acceleration G _Y , as shown in FIG.

The calculated lateral acceleration G _YB and the actual lateral acceleration G _Y
And the time difference is about 40 to 70 deg in terms of phase angle. Therefore, the phase delay amount β is 40 to 70 deg.
It is set to some value. The road surface state determination unit 82 includes a determination unit 82A that determines the road surface state based on the lateral acceleration, and a determination unit 82B that determines the road surface state based on the relationship between the steering angle θ and the power steering pressure Pst.

The determining unit 82A uses the phase delay unit 81 to phase the actual lateral acceleration (actual lateral acceleration) G _Y detected by the lateral G sensor 41 and the calculated lateral acceleration G _YB calculated by the calculated lateral acceleration computing unit 67. The delayed calculated lateral acceleration G _YB1 is compared, and if the delayed calculated lateral acceleration G _YB1 is larger than the actual lateral acceleration G _Y by a certain amount (d) or more, it is determined that the traveling road surface is a low μ road.

It should be noted that the determination by the determination unit 82A is based on the ratio G _Y / G of the actual lateral acceleration G _Y and the delay calculation lateral acceleration G _YB1.
It may be done by _YB1 . That is, as shown in the map of FIG. 23, if the value of G _Y / G _YB1 is in the region of m (m <1) or less, it is determined that the traveling road surface is a low μ road. If the power steering pressure Pst is smaller than a predetermined amount according to the steering angle θ, the determination unit 82B determines that the traveling road surface is a low μ road. For example, in the determination of the determination unit 82B, a power steering pressure P with respect to the steering angle θ is used by using a map as shown in FIG.
The running road surface state can be determined depending on which area on the map st is located. This is because the steering reaction force with respect to the steering angle θ becomes small on a low μ road, and the power steering pressure Pst adjusted according to the steering reaction force also becomes small with respect to the steering angle θ.

Then, the road surface condition judging section 82 of this embodiment
Then, if it is determined by either of the two determination units 82A and 82B that the traveling road surface is a low μ road, the traveling road surface is low μ.
It is decided to be a road. On the contrary, if both of the determination units 82A and 82B determine that the traveling road surface is not the low μ road, it is determined that the traveling road surface is not the low μ road. Then, the determination result as to whether or not the traveling road surface is a low μ road is output to the correction gain setting unit 83 as an electric signal.

The correction gain setting unit 83 sets the correction gain Kμ ₁ to 1 so that the actual correction is not performed when the traveling road surface is determined not to be a low μ road according to the output signal from the road surface condition determination unit 82. However, when the traveling road surface is a low μ road, the roll control gain (roll control amount)
The correction gain Kμ ₁ is set to a value appropriately smaller than ₁ so as to reduce However, this correction gain Kμ
_{The value 1} is set so that the driver can detect that the driver is traveling on a low μ road due to the increase in the roll amount, but the increase in the roll amount does not impair the stability of the vehicle.

In the road surface state correspondence correction unit 84, the roll control amount output from the adder 74 is multiplied by the correction gain Kμ ₁ set by the correction gain setting unit 83, and the integrated roll control gain is obtained. It is designed to output. On the other hand, in the roll control amount output from the roll control unit 50, the elements of the OS / US control are taken into consideration, and each wheel [right front wheel (FR), left front wheel (FL), right rear wheel (RR),
The left rear wheel (RL)] is output as a roll control amount (roll control gain).

That is, the front / rear distribution ratio setting unit 51A of the OS / US control unit 51 sets the front / rear distribution ratio α of the roll control amount K _R from the steering angle θ and the vehicle speed V. Then, the calculation unit 8
7, the front and rear distribution ratio α for each roll control amount K _R of the left and right wheels
Is multiplied by to calculate the roll control amount K _R of each wheel of FR, FL, RR, RL. The road surface condition is also taken into consideration in setting the front-rear distribution rate α. That is,
The front / rear distribution ratio α ′ set and output by the front / rear distribution ratio setting unit 51A is taken into the road surface state correspondence correction unit 86.
On the other hand, the signal from the above-mentioned road surface state determination unit 82 is sent to the correction gain setting unit 85. In the correction gain setting unit 85, the traveling road surface is low due to the output signal from the road surface state determination unit 82. When it is determined that the vehicle is not on the μ road, the correction gain Kμ ₂ is set to 1 so that the actual correction is not performed, and when the traveling road surface is determined to be the low μ road, the steering characteristic of the vehicle is set to the understeer side. Set the correction gain Kμ ₂ to.

In the road surface state correspondence correction unit 86, the front-rear distribution ratio α'output from the front-rear distribution ratio setting unit 51A is multiplied by the correction gain Kμ ₂ set by the correction gain setting unit 85 to obtain the front-rear distribution ratio α. Is to be output. Then, the calculation unit 87 is adapted to calculate the roll control amount K _R of each wheel of FR, FL, RR, RL by the front-rear distribution ratio α corrected as described above.

Since the vehicle road surface condition determining apparatus and the vehicle active suspension apparatus including the determining apparatus as one embodiment of the present invention are configured as described above, they operate as follows. In FIG. 15, the calculated lateral acceleration G _YB and the rate of change of the calculated lateral acceleration (differential value) are shown in the upper part.
'Is shown the time variation of the, G _YB and G _YB' G _YB since phase delay is not generated in the calculated value and, for ease of understanding, the time change characteristic of the G _YB and G _YB 'constant Will be explained as.

First, the calculated lateral acceleration G _YB in FIG. 15 corresponds to the steering operation of the steering wheel, and the actual lateral acceleration G _Y shown by the alternate long and short dash line in FIG. 15 occurs without a great delay in the steering operation. In such a situation, since the steering angular velocity θ'is slow and the vehicle speed V is slow, the control gains Kθ _B ′ and K _VB become 0 as shown in FIGS. 9 and 10, and the control amount corresponding to the calculated lateral acceleration G _YB becomes 0, the actual lateral acceleration G
_The control amount corresponding to _Y is output as it is from the adder 74 as the control amount for roll control indicated by the alternate long and short dash line. In such a situation, since the phase delay of the actual lateral acceleration G _{Y with} respect to the steering operation is small, the roll generation in the initial stage of turning does not become a problem and the generation of the vehicle body roll is appropriately suppressed.

Next, when the steering angular velocity θ'and the vehicle speed V increase and the phase delay of the actual lateral acceleration G _{Y with} respect to the steering operation increases as shown by the thick line in FIG. 15, the control gain K
As θ _B ′ and K _VB increase, a thick line control amount corresponding to the calculated lateral acceleration G _YB is generated, and is added to the thick line control amount corresponding to the actual lateral acceleration G _Y , and the phase delay changes little. The roll control amount indicated by a thick line with a small number is output from the adder 74. In such a situation, since the roll control amount has a small phase delay, it is possible to effectively prevent the roll generation in the initial stage of turning, and the roll stability is improved because the change of the roll control amount is small.

Further, as the steering angular velocity θ'and the vehicle speed V are further increased and the vehicle load is increased, the phase delay of the actual lateral acceleration G _{Y with} respect to the steering operation is further increased as shown by the thin line in FIG. If the calculated lateral acceleration G
_If the control amount indicated by the thick line corresponding to _YB is used, the roll control amount output from the adder 74 has a large variation as indicated by the dotted line, and the roll amount and the roll speed indicated by the dotted line in FIG. May increase, which may cause inconvenience to give an occupant a feeling of strangeness.

[0055] Therefore, in the present embodiment, the steering angular speed θ detected 'when particularly large area or load and the vehicle speed V is increased, the calculation lateral acceleration G _YB control gain K [theta _B corresponding to', K _VB and The characteristic is that K _LB relatively decreases with respect to the control gains Kθ ′, K _V and K _L corresponding to the actual lateral acceleration G _Y. As a result, in the above situation, the control amount corresponding to the calculated lateral acceleration G _YB is reduced as shown by the thin line in FIG. 15, and the roll control amount output from the adder 74 has a small phase delay as shown by the thin line. The change in the controlled variable becomes gradual. Therefore, the actual lateral acceleration G _Y
Even when the phase delay is extremely large, it is possible to exhibit a stable roll suppressing effect of the vehicle body as shown by the solid line in FIG.

That is, in the above embodiment, as shown in FIG. 17, the control gain Kθ _B ′ becomes 0 in the region where the steering angular velocity is θ ₁ ′ or less and the phase delay of the actual lateral acceleration G _Y is not a great problem. Output from the gain setter 70 is 0
Therefore, appropriate roll control mainly based on the actual lateral acceleration G _Y is executed in a region where the steering angular velocity is low.
Further, in a region where the steering angular velocity is higher than θ ₁ ′ and the phase delay of the actual lateral acceleration G _Y is a problem, the steering angular velocity is particularly θ.
_{In the range of 1} ′ to θ ₃ ′, the relative magnitude of the control gain Kθ _B ′ corresponding to the calculated lateral acceleration G _YB to the control gain Kθ ′ corresponding to the actual lateral acceleration G _Y is increased with an increase in the steering angular velocity. By doing so, the specific gravity of the control corresponding to the calculated lateral acceleration G _YB is increased, and the initial roll is extremely effectively prevented. Further, 'in a region where the phase difference is a problem with the high calculated lateral acceleration G _YB and actual lateral acceleration G _Y than, corresponding to compute the lateral acceleration G _YB control gain K [theta _B' steering angular velocity theta ₄ actual lateral acceleration By reducing the relative magnitude with respect to the control gain Kθ ′ corresponding to G _Y with the increase of the steering angular velocity, the fluctuation of the control amount is suppressed while the effect of suppressing the initial roll is obtained, and the body posture during roll control is stabilized. It can be done.

Further, as shown in FIG. 18, in a region where the vehicle speed is V ₁ or less and the phase delay of the actual lateral acceleration G _Y is not a significant problem, the control gain K _VB becomes 0 and the gain from the gain setter 71 is increased. Since the output becomes 0, appropriate roll control based on the actual lateral acceleration G _Y is mainly executed in the low vehicle speed region. In addition, the vehicle speed is higher than V ₁ and the actual lateral acceleration G is
Especially in the area where the phase delay of _Y is a problem, the vehicle speed is V
_{In the range of 1 to} V ₃ , by increasing the relative magnitude of the control gain K _VB corresponding to the calculated lateral acceleration G _YB with respect to the control gain K _V corresponding to the actual lateral acceleration G _Y as the vehicle speed increases. By increasing the specific gravity of control corresponding to the calculated lateral acceleration G _YB , the initial roll is extremely effectively prevented. Further, in a region where the vehicle speed is higher than V ₄ and the phase difference between the calculated lateral acceleration G _YB and the actual lateral acceleration G _Y becomes a problem, the control gain K _VB corresponding to the calculated lateral acceleration G _YB
By decreasing the relative magnitude with respect to the control gain K _V corresponding to the actual lateral acceleration G _Y as the vehicle speed increases,
It is possible to stabilize the body posture during roll control by suppressing the fluctuation of the control amount while obtaining the effect of suppressing the initial roll.

Further, with respect to the increase of the load which is another factor which causes the phase delay of the actual lateral acceleration G _Y , FIG. 7 and FIG.
As shown in Fig. 1, the relative magnitude of the control gain K _LB corresponding to the calculated lateral acceleration G _YB with respect to the control gain K _L corresponding to the actual lateral acceleration G _Y is set to be smaller as the load increases. Even if the phase difference between the lateral acceleration G _YB and the actual lateral acceleration G _Y becomes large, the roll stability can be suppressed by suppressing the fluctuation of the roll control amount, and the control gain K _L corresponding to the actual lateral acceleration G _Y can be obtained. Since the absolute value of is set to be large as the load increases, the roll can be appropriately suppressed with respect to the increase in the load.

In addition to such roll control,
Depending on whether the road surface of the vehicle is slippery (low μ road state), the roll control amount (roll control gain) is reduced in the flow shown in the flowchart of FIG. 14, for example. That is, data from each sensor is input (step S1), and the vehicle speed V is set to a set value (for example, 3 km) in each of steps S2 to S5.
/ H) or more, or the lateral acceleration is the set value a1 or more,
It is determined whether the steering angle θ _H is a set value (for example, 5 deg) or more and the power steering pressure Pst is a set value (for example, 5 kg / m) or more. If these are satisfied, that is, the steering operation is performed during traveling. When lateral acceleration occurs, the roll control amount reduction control is performed based on the determination of the road surface state determination unit 82.

That is, the steering angle is calculated by the calculation lateral acceleration calculation unit 67.
δ_HCalculated from the vehicle speed V and the lateral acceleration G _YBIs calculated (step
S6), the phase delay unit 81 calculates by filtering
Acceleration G_YBDelay calculation by delaying the phase of lateral acceleration G_YB1
Is calculated (step S7), and the determination unit 82A determines that the delay meter
Lateral acceleration G_YB1Is the actual lateral acceleration G_YThan the predetermined amount (d)
It is judged whether or not it is larger than the above (step S8), G
_YB1Is G_YIf it is larger than the specified amount by more than
Roll control gain as if the road (slippery surface)
(Roll control amount) is reduced (step S11).

Further, the determining unit 82B compares the relationship between the power steering pressure Pst and the steering angle θ with the map and the surface state (step S9) to determine whether the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side. It is judged (step S10). Then, when the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side, the roll control gain (roll control amount) is reduced (step S11).

That is, if the traveling road surface is determined to be a low μ road by either of the determination units 82A and 82B, it is determined that the traveling road surface is a low μ road, and this determination information is used as the correction gain setting. It is sent to the units 83 and 85, and the roll control amount and the front / rear distribution ratio are corrected. In addition, in this way, the determination unit 82
If the traveling road surface is a low μ road on either A or 82B, it is determined that the traveling road surface is a low μ road. Therefore, the low μ road determination can be reliably performed without omission of judgment, and particularly on a low μ road. It is suitable for the case where it is desired to control.

In the correction gain setting section 83, the correction gain K is set so as to reduce the roll control gain (roll control amount).
Set μ ₁ to a value appropriately smaller than ₁ . Then, the road surface condition corresponding correction unit 84 integrates the roll control amount output from the adder 74 with the correction gain Kμ ₁ set by the correction gain setting unit 83 to obtain the roll control gain K.
Output _R '.

The correction gain setting unit 85 sets the correction gain Kμ ₂ so that the steer characteristic of the vehicle is on the understeer side. Then, in the road surface state correspondence correction unit 86, the OS /
The front-rear distribution ratio α ′ set by the front-rear distribution ratio setting unit 51A of the US control unit 51 is multiplied by the correction gain Kμ ₂ to calculate the front-rear distribution ratio α. Further, the calculation unit 87 calculates the roll control amount K _R of each wheel of FR, FL, RR, RL from the roll control gain K _R ′ based on the front / rear distribution ratio α thus appropriately corrected.

As a result, the correction gain K μ ₁ causes the roll control gain K _R as shown by the solid line at the bottom of FIG.
Is reduced as the roll control gain K _R ′ shown by the chain line, and when the running road surface of the vehicle becomes a low μ road, the roll limitation of the vehicle body is released, and for example, the roll amount shown by the solid line to the roll shown by the broken line in FIG. The roll amount increases on the amount side. However, this increase in the roll amount is set to such an extent that the driver can detect that the vehicle is traveling on a low μ road, but the stability of the vehicle is not significantly impaired. As a result, it is possible to detect that the driver is traveling on a low μ road while obtaining a certain stability of the vehicle.

Further, when the traveling road surface of the vehicle becomes a low μ road by the correction gain Kμ ₂ , the steer characteristic is adjusted to the understeer side to secure the traveling stability of the vehicle which is easily lost when traveling on the low μ road. To be done. When the road surface condition determining unit 82 determines that the traveling road surface is a low μ road by both of the two determining units 82A and 82B, the traveling road surface is low μ.
It is also conceivable to configure so as to determine the road.

In this case, the judgment of the road surface condition judging section 82 and the roll control based on this judgment are performed, for example, in the flow shown in the flowchart of FIG. That is, data from each sensor is input (step S1), and in each step of steps S2 to S5, whether the vehicle speed V is a set value (for example, 3 km / h) or more, or the lateral acceleration is a set value a1 or more. , The steering angle θ _H is a set value (for example, 5 de
g) or more or the power steering pressure Pst is a set value (for example, 5).
kg / m) or more, respectively, and when these are satisfied, that is, when a lateral operation is generated by performing a steering operation during traveling, the roll control amount reduction control is performed based on the determination of the road surface state determination unit 82. Do.

That is, the calculated lateral acceleration calculation unit 67 calculates the calculated lateral acceleration G _YB from the steering angle δ _H and the vehicle speed V (step S6), and the phase delay unit 81 filters the calculated lateral acceleration G _YB phase. Delay and calculate delay Lateral acceleration G _YB1
Is calculated (step S7), and the determination unit 82A determines that the delay calculation lateral acceleration G _YB1 is a predetermined amount (d) more than the actual lateral acceleration G _Y.
If it is larger than the above (step S8) and the delay calculation lateral acceleration G _YB1 is larger than the actual lateral acceleration G _Y by a predetermined amount d or more, the determining unit 82B further determines the power steering pressure Pst.
The relationship between the steering angle θ and the steering angle θ is compared with the map (step S9), and it is determined whether the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side (step S10). When the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side, it is determined here that the traveling road surface is the low μ road,
The roll control gain (roll control amount) is reduced (step S11).

As described above, since both of the determination units 82A and 82B determine that the traveling road surface is the low μ road only after the traveling road surface is the low μ road, the low μ road condition is made strict and unnecessary. It is suitable when it is desired to avoid such low μ road control. In addition, the road surface state determination unit 82 is replaced by the two determination units 82.
It may be configured with only one of A and 82B.

When the road surface condition judging unit 82 is composed of only the judging unit 82A, the judgment of the road surface condition judging unit 82 and the roll control based on this judgment are performed, for example, in the flow shown in the flowchart of FIG. In addition, the road surface condition determination unit 82
If only the determination unit 82B is used, the road surface state determination unit 82
21 and roll control based on this determination are shown in FIG.
The flow is as shown in the flowchart of FIG. Since the steps of the flowcharts of FIGS. 20 and 21 are the same as the corresponding steps of FIGS. 14 and 19,
The description is omitted.

In addition to the control of the vehicle active suspension device, this vehicle road surface condition determination device is, for example, a drive force distribution control for a four-wheel drive vehicle, a steering distribution control for each wheel of a four-wheel steering vehicle, and the like. It can be widely applied to various vehicle controls. The vehicle road surface condition determination device and the vehicle active suspension device according to the present invention are not limited to the above-described embodiments, and the gain setting devices 64, 65, 71, 73 can be omitted. It is also possible to change the form of each control gain map and the like. Further, a sensor for directly detecting the steering angular velocity may be used as the steering angular velocity detecting means. In any case, it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0072]

As described in detail above, the first aspect of the present invention
The vehicle road surface state detecting device for a vehicle is provided with a vehicle speed detecting means for detecting a vehicle speed of the vehicle and a steering angle for detecting a steering angle of the vehicle in a vehicle having a power steering for exerting a steering assist force according to a steering reaction force. Detection means, lateral acceleration detection means for detecting lateral acceleration applied to the vehicle, steering assist force detection means for detecting steering assist force of the power steering, vehicle speed detected by the vehicle speed detection means, and steering angle detection A lateral acceleration calculating means for calculating a lateral acceleration that should occur in the vehicle based on the steering angle detected by the means, a value of an actual lateral acceleration detected by the lateral acceleration detecting means, and a lateral acceleration calculating means. A first judgment for comparing the calculated calculated lateral acceleration value and judging that the road surface is in a slippery state when the actual lateral acceleration value is larger than the calculated lateral acceleration value by a predetermined amount or more. And the road surface is in a slippery state when the magnitude of the steering assist force detected by the steering assist force detecting means is smaller than the required amount with respect to the magnitude of the steering angle detected by the steering angle detecting means. And a second judging means for judging that the road surface is slippery when it is judged that the road surface is slippery by one of the first judging means and the second judging means. With such a configuration, the low μ road determination can be reliably performed without omission of the determination, and particularly, the control can be reliably performed on the low μ road, which can contribute to the improvement of the control performance.

According to a second aspect of the present invention, there is provided a vehicle road surface state detecting device, which is a vehicle speed detecting means for detecting a vehicle speed of a vehicle in a vehicle equipped with a power steering which exerts a steering assist force according to a steering reaction force. Steering angle detecting means for detecting a steering angle of the vehicle, lateral acceleration detecting means for detecting a lateral acceleration applied to the vehicle, steering assist force detecting means for detecting a steering assist force of the power steering, and vehicle speed detection A lateral acceleration calculating means for calculating a lateral acceleration that should occur in the vehicle based on the vehicle speed detected by the means and the steering angle detected by the steering angle detecting means; and an actual lateral acceleration detected by the lateral acceleration detecting means. The value of the acceleration is compared with the value of the calculated lateral acceleration calculated by the lateral acceleration calculating means, and when the actual value of the lateral acceleration is larger than the calculated lateral acceleration by a predetermined amount or more, the road surface slips. The first judging means for judging that the steering assist force is in a non-operating state, and the magnitude of the steering assist force detected by the steering assist force detecting means with respect to the magnitude of the steering angle detected by the steering angle detecting means. And a second judging means for judging that the road surface is in a slippery state when both are smaller than the above, both of the first judging means and the second judging means judges that the road surface is in a slippery state. It is configured to determine that the road surface is in a slippery condition when it is carried out, so that the low μ road condition is rigorously and appropriately performed, which is suitable when it is desired to avoid unnecessary low μ road control, etc. It can contribute to the improvement of performance.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a main part configuration of a roll control system (including an OS / US control system) of a vehicle active suspension device including a vehicle road surface condition determination device as one embodiment of the present invention. ..

FIG. 2 is a schematic configuration diagram showing a mechanism of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 3 is a block diagram showing an overall configuration of a control system of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 4 is a control gain map for controlling an active suspension system for a vehicle having a vehicle road surface condition determination system as one embodiment of the present invention.

FIG. 5 is a control gain map relating to control of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 6 is a control gain map relating to control of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 7 is a control gain map relating to control of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 8 is a control gain map relating to the control of the vehicle active suspension device including the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 9 is a control gain map for controlling an active suspension system for a vehicle including a vehicle road surface condition determination system as one embodiment of the present invention.

FIG. 10 is a control gain map relating to control of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 11 is a control gain map relating to control of a vehicle active suspension device including a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 12 is a determination map relating to road surface state determination of a vehicle road surface state determination device as one embodiment of the present invention.

FIG. 13 is a schematic view of a portion related to low μ road control of a roll control system (including an OS / US control system) of a vehicle active suspension device including a vehicle road surface condition determination device as one embodiment of the present invention. It is a schematic structure figure shown.

FIG. 14 is a flowchart regarding low μ road control of a roll control system (including an OS / US control system) of a vehicle active suspension device including a vehicle road surface state determination device according to an embodiment of the present invention.

FIG. 15 is a characteristic diagram of the roll control amount of the vehicle active suspension device including the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 16 is a characteristic diagram showing a roll state of the vehicle body by the vehicle active suspension device including the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 17 is a diagram comparing characteristics of control gains that change with respect to a steering angle by an active suspension system for a vehicle including a vehicle road surface condition determination system according to an embodiment of the present invention.

FIG. 18 is a diagram comparing characteristics of respective control gains that change with respect to a vehicle speed by the vehicle active suspension device including the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 19 is a flowchart relating to a first modified example of the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 20 is a flowchart relating to a second modified example of the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 21 is a flowchart relating to a third modified example of the vehicle road surface state determination device as one embodiment of the present invention.

FIG. 22 is a graph illustrating a phase correction of data performed for road surface condition determination of the vehicle road surface condition determination device as one embodiment of the present invention.

FIG. 23 is a determination map relating to road surface state determination of the vehicle road surface state determination apparatus as one embodiment of the present invention.

[Explanation of symbols]

1 oil pump 2 oil passage 3 reserve tank 4, 4F, 4R supply oil passage 4F front wheel side oil passage 4R rear wheel side oil passage 5, 6 accumulator 7, 8 oil filter 9 pilot relief oil passage 10 relief oil passage 11 solenoid valve 12 Discharge oil passage 13, 13F, 13R Return oil passage 14 Operate check valve 15 Relief valve 16 Oil cooler 17 Oil filter 18 Relief valve 19F, 19R Accumulator 20F, 20R Check valve 22FL, 22FR, 22RL, 22RR Suspension unit 23FL, 23FR, 23RL , 23RR Check valve 24F, 24RL, 24RR Throttle 25 Accumulator 26 Relief valve 27 Cock 30 Hydraulic actuator 31 Oil passage 32 Control valve 33 Throttle 34 Accumulator 35 Damping force control valve 36 Pressure sensor 40 Controller 40A Steering control part 40B Attitude control part 40C Ride comfort control part 41 Lateral G sensor 42 Steering angle sensor 43 Vehicle speed sensor 44 Front / rear G sensor 45 Brake switch 46 Throttle sensor 47, 47A -47D Stroke sensor 48 Vertical G sensor 49 Preview sensor 50 Anti-roll control unit 50A Main part of anti-roll control unit 51 OS / US control unit (steer control unit) 51A OS / US control unit (steer control unit) main Part 52 Anti-pitch control part 55 Vehicle height control part 56 Composite control part 57 Adder 58 Drive circuit 59 Preview control part 60 Drive circuit 81 Phase delay part 82 Road surface condition determination part (road surface condition determination means) 82A, 82B determination part 83 , 85 Correction Down setting unit 84 and 86 the road surface condition corresponding correction unit 87 calculating unit 142 roll control correction unit 143 OS / US control compensation unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 111: 00 113: 00 117: 00 123: 00 131: 00 (72) Inventor Yasutaka Taniguchi Tokyo 5-33-8 Shiba, Minato-ku, Mitsubishi Motors Corporation (72) Inventor Naohiro Kishimoto 5-33-8, Shiba, Minato-ku, Tokyo (72) Inventor, Hiroaki Yoshida Minato-ku, Tokyo 5-33-8 Shiba Mitsubishi Motors Co., Ltd.

Claims (2)

[Claims] 1. In a vehicle equipped with a power steering device that exerts a steering assist force in accordance with a steering reaction force, a vehicle speed detecting means for detecting a vehicle speed of the vehicle, and a steering angle detecting means for detecting a steering angle of the vehicle. Lateral acceleration detecting means for detecting lateral acceleration applied to the vehicle, steering assisting force detecting means for detecting steering assisting force of the power steering, vehicle speed detected by the vehicle speed detecting means, and steering angle detecting means. The lateral acceleration calculating means for calculating the lateral acceleration to be generated in the vehicle based on the steering angle, the value of the actual lateral acceleration detected by the lateral acceleration detecting means, and the calculation lateral force calculated by the lateral acceleration calculating means. First judging means for comparing the acceleration value with the actual lateral acceleration value to judge that the road surface is slippery when the calculated lateral acceleration value is larger than the calculated lateral acceleration value by a predetermined amount or more; Secondly, when the magnitude of the steering assist force detected by the steering assist force detector is smaller than the required amount with respect to the magnitude of the steering angle detected by the angle detector, the road surface is determined to be slippery. With the judgment means of
When the road surface is determined to be slippery by one of the first determination means and the second determination means, the road surface is determined to be slippery. , Road surface condition determination device for vehicle. 2. A vehicle equipped with a power steering system that exerts a steering assist force according to a steering reaction force, a vehicle speed detecting means for detecting a vehicle speed of the vehicle, and a steering angle detecting means for detecting a steering angle of the vehicle. Lateral acceleration detecting means for detecting lateral acceleration applied to the vehicle, steering assisting force detecting means for detecting steering assisting force of the power steering, vehicle speed detected by the vehicle speed detecting means, and steering angle detecting means. The lateral acceleration calculating means for calculating the lateral acceleration to be generated in the vehicle based on the steering angle, the value of the actual lateral acceleration detected by the lateral acceleration detecting means, and the calculation lateral force calculated by the lateral acceleration calculating means. First judging means for comparing the acceleration value with the actual lateral acceleration value to judge that the road surface is slippery when the calculated lateral acceleration value is larger than the calculated lateral acceleration value by a predetermined amount or more; Secondly, when the magnitude of the steering assist force detected by the steering assist force detector is smaller than the required amount with respect to the magnitude of the steering angle detected by the angle detector, the road surface is determined to be slippery. With the judgment means of
Both of the first determining means and the second determining means are configured to determine that the road surface is in a slippery state when both determine that the road surface is in a slippery state. , Road surface condition determination device for vehicle.