JPH02274669A - Vehicle state observer - Google Patents

Abstract

PURPOSE:To prevent the lowering of zero estimate updating accuracy by setting the weight of weighted mean operation in such a way as to reduce the zero estimate specific gravity when the change rate of the vehicle state quantity detection value against the steering angle change is increased as car speed changes and increase the detected value specific gravity when the change rate is reduced. CONSTITUTION:The vehicle state observer 30 of a steering control device 20 estimates the zero value of the vehicle state at a zero estimate update means 38 from the signals of a vehicle state quantity detecting means 32 (for instance in a yaw rate sensor, the yaw rate equal to zero corresponds to the zero value of the vehicle state quantity) and a steering angle detecting means 34, performs the weighted mean of the estimated zero value and the zero estimate of the initial state from a memory means 36 with the weight by a setting means 42, and performs steering by a front and a rear steering control signal output means 16, 18 on the basis of the updated zero estimate. With the speed change detected by a speed detecting means 40, the weight K is made the small value when steering gain is reduced so as to prevent the lowering of zero estimate updating accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle state quantity n1 device used for steering control of a vehicle.

[Prior Art] Conventionally, auxiliary steering of front wheels or rear wheels has been performed in order to always maintain the maneuverability and stability of a vehicle in a predetermined state. In this auxiliary steering control, vehicle state quantities that change depending on the running state of the vehicle, such as information such as lateral acceleration and yaw rate, are used. Such a conventional technique is disclosed in, for example, Japanese Patent Laid-Open No. 60-92976.

The steering control device that controls the auxiliary steering is configured to include a vehicle condition observation device and a steering control signal output means. That is, the vehicle state observation device includes vehicle state quantity detection means for detecting vehicle state quantities that change depending on the running state of the vehicle, such as lateral acceleration and yaw rate, and the information on the vehicle state quantities detected by the means is used as a steering control signal. It is output to the output means.

Next, the steering control signal output means uses the detected vehicle state quantity information to calculate a numerical value indicating the steering performance and stability of the vehicle, that is, a stability factor, and compares the factor with a target value. , determines the amount of auxiliary steering for the front or rear wheels. Then, a control signal corresponding to the determined auxiliary steering amount is output to the steering mechanism that performs the auxiliary steering.

According to the steering control device configured to include such a vehicle state quantity n1 device, the steering performance and stability of the vehicle can be maintained in a predetermined state even when the vehicle turns.

[Problems to be Solved by the Invention] However, this prior art has a problem in that the output of the vehicle condition observation device deviates due to environmental changes or changes over time. That is, when the zero value of the vehicle state quantity detection means, which is the output of the vehicle state quantity detection means when the vehicle state quantity is zero, changes due to an environmental change or a change over time, the vehicle state observation device detects the changed zero value. Since the vehicle state quantity information is output based on the vehicle state quantity information, the vehicle state quantity information includes a deviation due to a zero value change of the vehicle state quantity detection means.

In order to solve such problems, the applicant first proposed a system in which even when the zero value of the vehicle-like MI amount detection means changes due to environmental changes or changes over time, there is no deviation in the vehicle state amount information due to the change in the zero value. We proposed a vehicle condition observation device that outputs the information without including it. That is, this vehicle state observation device includes a steering angle detection means for detecting a steering angle, and a zero estimated value storage means for storing an output value of the vehicle state amount detection means when the vehicle state amount is zero as a zero estimated value. , when the steering angle detected by the steering angle detection means is less than a predetermined value, the zero estimated value of the vehicle state quantity detection means stored in the zero estimated value storage means is updated, and this update is stored in the zero estimated value storage means. The zero estimated value of the vehicle state quantity detection means and the vehicle state! 2! The weighted average calculation with the detected value of the vehicle state quantity detected by the quantity detection means and the writing of the calculation result into the zero estimated value storage means are performed, and the weighting in the weighted average calculation is carried out using the vehicle stored in the zero estimated value storage means, and zero estimated value updating means that performs the process by giving specific weight to the zero estimated value of the image state quantity detecting means, and when the output of the vehicle state quantity detecting means can be estimated to be a zero value, the zero estimated value updating means The present invention is characterized in that the zero estimated value is updated using the updated zero estimated value, and vehicle state quantity information is output using the updated zero estimated value.

According to the vehicle state observation device having such a configuration, even when the zero value of the vehicle state quantity detection means changes due to environmental changes or changes over time, the zero estimated value of the vehicle state quantity detection means is updated by the zero estimated value updating means. is updated. Since the vehicle state quantity information output from the vehicle state observation device is based on the zero estimated value updated by the zero estimated value updating means, the information includes the zero value of the vehicle state quantity detecting means. In this way, even when the zero value changes due to an environmental change or a change over time, it is possible to output vehicle state quantity information that does not include a deviation due to the change in the zero value.

However, in a vehicle state observation device having such a configuration, the ratio of change in the detected value of the vehicle state amount detection means to a change in the steering angle (hereinafter referred to as the steering gain of the vehicle state amount detection means) is dependent on the change in vehicle speed. When it increases,
There was a problem in that the accuracy of updating the zero estimate value decreased.

That is, when the steering gain increases due to a change in vehicle speed, especially near the threshold value of the steering angle at which the zero estimated value is updated, the difference between the detected value of the vehicle state quantity detection means and the zero value increases. increases, and the accuracy of the zero estimate update performed by weighted average calculation using the detected values decreases.

On the other hand, the vehicle state observation device has a problem in that when the steering gain decreases with a change in vehicle speed, the zero estimate value update is not performed effectively. That is,
When the steering gain decreases due to a change in vehicle speed, the amount of change in the zero estimate value associated with updating the zero estimate value is small, and the amount of update of the zero estimate value associated with one update of the zero estimate value is small. When the direction of travel of the vehicle is frequently changed by steering, the frequency of updating the zero estimate value also decreases due to the steering angle threshold condition for updating the zero estimate value. In this way, the speed at which the zero estimate value converges to the zero value due to the update of the zero estimate value decreases, so it is not possible to effectively prevent deviations in the vehicle state quantity output due to environmental changes, changes over time, or the like.

The present invention has been made with the aim of solving these problems, and it is possible to prevent the accuracy of updating the zero estimate from decreasing even when the steering gain of the vehicle state quantity detection means changes with changes in vehicle speed. It is an object of the present invention to provide a vehicle condition observation device that can prevent the above update and effectively perform the update.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a vehicle speed detection means for detecting the vehicle speed, and a vehicle state quantity detection means that detects a change in the rate of change in the detected value of the vehicle state quantity detection means with respect to a change in the steering angle. When the ratio increases with a change in vehicle speed, the specific weight of the zero estimated value of the vehicle state quantity detection means stored in the zero estimated value storage means increases, and when the ratio decreases with a change in vehicle speed, the specific weight of the zero estimated value of the vehicle In order to increase the specific gravity of the detected value of the state quantity detection means,
weight setting means for setting a weight to be used in the weighted average calculation according to the vehicle speed detected by the vehicle speed detection means, and a ratio of change in the detected value of the vehicle state quantity detection means to a change in the steering angle. Even when the value changes with a change in vehicle speed, the weighted average calculation is performed using the weight set by the weight setting means to update the zero estimate, and the updated zero estimate is used to update the vehicle state information. It is characterized by outputting.

[Operation] Therefore, according to the present invention, when the steering gain of the vehicle state quantity detection means increases with a change in vehicle speed, the weight in the weighted average calculation related to updating the zero estimate value is stored in the zero estimate storage means. Since the specific gravity of the zero estimated value of the vehicle state quantity detecting means is set to increase, it is possible to prevent a decrease in accuracy of updating the zero estimated value due to an increase in the difference between the detected value of the vehicle state quantity detecting means and the zero value. Further, when the steering gain decreases due to a change in vehicle speed, the weight in the calculation is set so that the detection value of the vehicle state quantity detection means increases, so that Even when the amount of updating of the zero estimate value increases and the frequency of updating the zero estimate value decreases due to the threshold condition of the steering angle for updating the zero estimate value,
The convergence speed of the zero estimate to the zero value is maintained, and the zero estimate can be updated effectively.

[Embodiment] Hereinafter, a vehicle condition observation device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram for explaining the overall configuration of this embodiment. The vehicle according to this embodiment is a four-wheel steering vehicle, and a front wheel steering mechanism 10 and a rear wheel steering mechanism 12 are connected to the front wheels FW and rear wheels RW, respectively.

Further, a steering handle SW is connected to the front wheel steering mechanism 10.

That is, the front wheels FW are steered by the front wheel steering mechanism 10 (main steering) according to the rotation angle of the steering handle SW (hereinafter referred to as steering angle).

The front wheel steering mechanism 10, via the front wheel correction steering mechanism 14,
It is controlled by front wheel steering control signal output means 16. Further, the rear wheel steering mechanism 12 is controlled by a rear wheel steering control signal output means 18. That is, the means 1
6 and 18 output control signals for auxiliary steering of the front wheels FW and rear wheels RW, respectively, and these signals are input to the front wheel correction steering mechanism 14 and the rear wheel steering mechanism 12, respectively. Therefore, the front wheel FW and the rear wheel RW are
and 18.

The steering control device 20 includes a front wheel steering control signal output means 16,
It is configured to include a rear wheel steering control signal output means 18 and a vehicle condition observation device 30 according to the present invention. That is, vehicle state quantity information, which is the output of the vehicle state observation device 30, is input to the means 16 and 18, and the means 16 and 1
8 uses the information to determine the amount of auxiliary steering for the front wheels and rear wheels.

The vehicle state observation device 30 according to the present invention includes a vehicle state amount detection means 32, a steering angle detection means 34, a zero estimated value storage means 36,
It is configured to include a zero estimate updating means 38, a vehicle speed detecting means 40, and a weight setting means 42.

A zero estimated value updating means 38 is connected to the vehicle state quantity detection means 32 that detects vehicle state quantities that change depending on the running state of the vehicle, and the means 38 receives vehicle state quantity information aN detected by the means 32. is input. Here, the means 3
When the vehicle state quantity detected by 2 is a yaw rate, the means 32 is a yaw rate sensor comprised of, for example, a vibrating gyroscope. in this case,
The vehicle state quantity information aN is a voltage determined according to the yaw rate, and the voltage when the yaw rate is equal to zero is
Vehicle-like! ! Corresponds to the zero value of the quantity.

The steering handle SW is provided with a steering angle detecting means 34 for detecting the steering angle, and the steering angle information δSν detected by the means 34 is inputted to the zero estimate updating means 38.

The zero estimated value updating means 38 that updates the zero estimated value is connected to the vehicle state quantity detecting means 32, the steering angle detecting means 34, the weight setting means 42, and the zero estimated value storing means 36.

That is, the zero estimated value aO of the vehicle condition a quantity detection means 32 is stored in the zero estimated value storage means 3δ, and the zero value information is inputted to the zero estimated value updating means 38. On the other hand, the vehicle state quantities and steering angle information detected by the means 32 and 34 are input to the zero estimate updating means 38, and the means 38 uses the information and the zero estimate aO to update the zero estimate, which will be described later. The value is updated. Further, the new zero estimate aO updated by the zero estimate update is stored in the zero estimate storage means 36.

Vehicle state quantity information based on the zero estimated value aO updated by the zero estimated value updating means 38 is input to the front wheel steering control signal output means 1G and the rear wheel steering control signal output means 18. That is, vehicle state quantity information that does not include deviations due to zero value changes of the vehicle state quantity detection means 32 is input to the means 16 and 18.

The weight setting means 42, which is also a feature of the present invention, is connected to the vehicle speed detection means 4G, which is a feature of the present invention, and the zero estimate updating means 38 is connected to the weight setting means 42. That is, a weight k is set in the weight setting means 42 based on the vehicle speed V detected by the vehicle speed detection means 40, and the set weight k is supplied to the zero estimate updating means 38 and used for updating the zero estimate to be described later. It will be done.

Therefore, according to the vehicle state observation device 30 according to this embodiment, the zero estimate value is updated using the weight k set by the weight setting means 42 according to the vehicle speed V, and the updated zero estimate value aO is It is possible to output vehicle state quantity information by using

Next, the first operation of the vehicle condition observation device 30 according to this embodiment will be explained using FIG. 2.

FIG. 2(a) is a flowchart of updating the zero estimate value including setting of the weight k according to the vehicle speed V, which is a feature of the present invention.

After the ignition of the engine is turned on, after the time required for the output of the vehicle state quantity detection means 32 to stabilize, the zero estimated value updating means 38 starts operating (100). Furthermore, the initial state zero estimate aO is read from the zero estimate storage means 36 (200).

In the present invention, this zero estimated value aO is the output value of the vehicle state quantity detection means when the vehicle state quantity is zero, and in the embodiment, the vehicle state at the end of the previous run is used as the initial state zero estimated value aO. The zero estimated value of the quantity detection means 32 or a preset zero estimated value is used.

Setting the weight k (V) (30O), which is a feature of the present invention, involves reading the vehicle speed V (310) and referencing the vehicle speed (300).
20). That is, the vehicle speed detection means 40
The detected vehicle speed V is referred to a map stored in the weight setting means 42, and a weight k (V) is set.

Here, the map related to the determination of the weight k (V) is a curve showing the relationship between the vehicle speed V and the weight k as shown in FIG. 2(b) in this operation, and the map related to the weighted average calculation is The weight k is predetermined according to the response of the steering gain of the vehicle state quantity detection means 32 to the vehicle speed ■. That is, the map is determined so that when the steering gain increases with a change in the vehicle speed V, the weight k becomes a small value, and when the steering gain decreases, the weight k becomes a large value. stored internally.

Further, the weight k of the weighted average can be set in the range of 0<k<1, but by setting the weight k so that the relationship Q<k<<1-k<1 holds,
It is possible to prevent a decrease in the accuracy of zero estimated value calculation, which will be described later, due to fluctuations in the output of the vehicle state quantity detection means 32.

Next, it is determined whether the absolute value of the steering angle δSw is smaller than a predetermined value δ0 (for example, 10') (400).

As a result of this determination, the absolute value of the steering angle δSv is a predetermined value δO.
If it is smaller, the process moves to step 500 to perform a zero estimate update. In other cases, the process moves to step 800 without updating the zero estimated value.

In step 500, the vehicle state quantity detected by the vehicle state quantity detection means 32, that is, the detected value aN, is read into the zero estimate updating means 38 for the next weighted average calculation. Here, by the process of step 400, the steering angle δ
Since the absolute value of Sw is smaller than the predetermined value δO, the detected value a
N can be considered to be approximately equal to vehicle state quantity information when the steering angle δSW is zero, that is, a zero value.

Next, a weighted average of aO and the detected value aN is calculated, and the weighted average is set to a new zero estimate aO (600).
. Here, as shown in FIG. 2(b) in step 300, since the weight k is set according to the vehicle speed V, the increase in the steering gain of the vehicle state quantity detection means 32 due to the change in the vehicle speed V is When this occurs, the amount of updating of the zero estimate aO per weighted average calculation is reduced, and a decrease in the accuracy of updating the zero estimate aO due to the calculation is prevented. Conversely, vehicle speed V
When the steering gain of the means 32 decreases due to a change in the steering gain, the amount of updating of the zero estimate aO per weighted average calculation increases. For example, when steering is performed frequently, the steering angle δSv at step 400 Even when the frequency of the calculation decreases due to the determination, the speed of convergence of the zero estimate to the zero value is maintained, and the zero estimate can be updated effectively.

In step 700, the new zero estimate aO
is written into the zero estimate storage means 36.

Then, it is determined whether to continue updating the zero estimated value (800). When the ignition is turned off and when there is an abnormal output from the vehicle state 7@ quantity detection means 32, the zero estimated value update is ended (900). In other cases, the process moves to step 300 and a new zero estimate a
Continue to update the zero estimate using O.

Therefore, according to the vehicle state observation device 30 having such an operation, even when the steering gain of the vehicle state amount detection means 32 changes with a change in the vehicle speed V, a decrease in the accuracy of updating the zero estimated value is prevented, Moreover, the update can be performed effectively.

Next, a second operation of the vehicle condition observation device 30 according to this embodiment will be explained using FIG. 3. This figure shows a map related to the setting of weight k in this operation.

In this operation, when the vehicle speed V is greater than a predetermined value VO, the weight k is set to a predetermined value kO;
In the following cases, the weight k is set to a predetermined value kmax. Here, the predetermined values kO and k laX are predetermined so that the relationship 1 kmax>kO holds.

Therefore, such a map is used when the vehicle state quantity detection means 32 is used in which the steering gain increases significantly as the vehicle speed V increases. That is, in such a case, when the vehicle speed V is large, the steering gain is large;
When the steering gain is small, the steering gain is small. Therefore, by using a map such as the one shown in FIG. can be set to a large value.

According to the vehicle condition observation device 30 having such an operation,
As in the case of the first operation, it is possible to prevent the accuracy of the zero estimate update from decreasing and the effect of the update from decreasing. In addition, map weight setting means 42 as shown in FIG.
In internal storage, predetermined values kO, VO,
Since it is only necessary to store kI5ax, etc., it is possible to omit part of the configuration required for this storage. Furthermore, the weight k (
It is possible to shorten the time required for referring to V).

FIG. 4 shows a map used for the third operation of the vehicle condition observation device 30 according to this embodiment.

In this operation, the weight k is set to zero when the vehicle speed V is greater than a predetermined value vO, and the weight k is set to a predetermined value kff1ax when the vehicle speed V is less than or equal to the predetermined value VO.

According to the operation using such a map, similarly to the second operation, even when the steering gain of the vehicle state quantity detection means 32 changes with a change in the vehicle speed V, a decrease in the accuracy of updating the zero estimated value can be prevented. In addition, the update can be performed effectively.

In addition, similar to the second operation, it is possible to partially omit the configuration required for storage within the weight setting means 42 and shorten the time required to refer to the weight k (V).

[Effects of the Invention] As explained above, according to the vehicle state observation device according to the present invention, even when the steering gain of the vehicle state quantity detection means changes with a change in vehicle speed, the accuracy of updating the zero estimated value decreases. This can be prevented and the update can be performed effectively.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram of a system using a vehicle condition observation device according to an embodiment of the present invention, and Fig. 2 is a diagram showing the configuration of a system using a vehicle condition observation device according to this embodiment. 1
FIG. 2(a) is a flowchart diagram showing this operation, FIG. 2(b) is a map diagram used for this operation, and FIG. 3 is a diagram showing the vehicle state according to this embodiment. Map diagram used for the second operation of the observation device. FIG. 4 is a map diagram used for the third operation of the vehicle condition observation device according to this embodiment. 30...Vehicle state observation device 32...Vehicle state quantity detection means 34...Steering angle detection means 36...Zero estimated value storage means 38...Zero estimated value updating means 40...Vehicle speed detection means 42... Weight setting means

Claims (1)

[Scope of Claims] Vehicle state quantity detection means for detecting vehicle state quantities such as lateral acceleration and yaw rate that change depending on the running state of the vehicle; steering angle detection means for detecting a steering angle; a zero estimated value storage means for storing an output value of the vehicle state quantity detection means at a certain time as a zero estimated value; and a zero estimated value storage means for storing an output value of the vehicle state quantity detection means at a certain time as a zero estimated value; The stored zero estimated value of the vehicle state quantity detection means is updated, and this update is performed using the zero estimated value of the vehicle state quantity detection means stored in the zero estimated value storage means and the vehicle detected by the vehicle state quantity detection means. A vehicle state observation device having a weighted average calculation with a detected value of a state quantity and a zero estimate value updating means performed by writing the calculation result to a zero estimate value storage means, comprising: a vehicle speed detection means for detecting vehicle speed; When the rate of change in the detected value of the vehicle state quantity detection means with respect to change increases with a change in vehicle speed, the relative weight of the zero estimated value of the vehicle state quantity detection means stored in the zero estimated value storage means increases. In addition, when the ratio decreases with a change in vehicle speed, the weighted average calculation is performed according to the vehicle speed detected by the vehicle speed detection means so that the specific weight of the detected value of the vehicle state quantity detection means increases. weight setting means for setting a weight, and the weight setting means sets the weight even when the ratio of change in the detected value of the vehicle state quantity detection means to a change in the steering angle changes with a change in vehicle speed. A vehicle state observation device characterized in that the weighted average calculation is performed using the weighted weights, the zero estimated value is updated, and the updated zero estimated value is used to output vehicle state amount information.