JP4200970B2 - Swing control device - Google Patents

Description

  The present invention relates to a turning control device that improves operability and stability of a vehicle.

Conventionally, a reference yaw rate calculation device that calculates a target yaw rate of a vehicle with high accuracy by appropriately changing a steering gear ratio for calculating the target yaw rate of the vehicle is known (for example, see Patent Document 1).
JP 2000-95085 A

  However, in the above-described conventional reference yaw rate calculation device, the vehicle is not controlled based on the rising slope or the falling slope of the stability factor. In addition, it cannot be said that the turning of the vehicle is controlled based on a change in the stability factor that is an indicator of vehicle under-steering or over-steering. It is hard to say that it can be suppressed without feeling uncomfortable.

  The present invention has been made to solve such problems, and has as its main object to improve the operability and stability of the vehicle.

  One aspect of the present invention for achieving the above object is a state quantity acquisition unit that acquires a state quantity of a vehicle, and the vehicle in a turning state based on the state quantity of the vehicle acquired from the state quantity acquisition unit. A stability control unit for calculating the stability factor of the vehicle, and a turn control device comprising: an increase gradient or a decrease in the stability factor based on the stability factor calculated by the stability factor calculation unit A slope calculating means for calculating a slope; and a control means for controlling the behavior of the vehicle so that the ascending slope or the descending slope calculated by the slope calculating means is not more than a predetermined value. This is a turning control device.

  In this aspect, the rising or falling slope of the stability factor refers to the amount of change per unit time of the stability factor.

  In this aspect, controlling the behavior of the vehicle means, for example, adjusting engine output, torque transmission rate in the transmission, and the like.

  According to this aspect, based on the stability factor calculated by the stability factor calculation unit, the gradient calculation unit that calculates the rising gradient or the falling gradient of the stability factor, and the gradient calculation unit calculates the gradient. Control means for controlling the behavior of the vehicle so that the ascending gradient or the descending gradient is equal to or less than a predetermined value. Thereby, the behavior of the vehicle is controlled so that the rising slope and the falling slope of the stability factor are in a gradual state. Therefore, understeering and oversteering of the vehicle are suppressed, and operability and stability of the vehicle are improved.

  In the above aspect, the state quantities of the vehicle are the speed of the vehicle, the yaw rate of the vehicle, the steering angle of the vehicle, the steering gear ratio of the vehicle, and the wheelbase of the vehicle.

  In the aspect, it is preferable that the control unit controls the behavior of the vehicle so as to suppress under steering or over steering of the vehicle.

  According to the present invention, the operability and stability of the vehicle can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept, main hardware configuration, operating principle, basic control method, and the like of the control device for a vehicle are known to those skilled in the art, and thus detailed description thereof is omitted.

  FIG. 1 is a schematic diagram of a system configuration showing a turning control device according to an embodiment of the present invention. As shown in FIG. 1, the turning control device 1 according to the present embodiment is configured around an electronic control unit (hereinafter referred to as “ECU”) 3. ECU3 is comprised as a microcomputer which consists of CPU, ROM, RAM, etc. which were mutually connected via the bus | bath. The ROM stores a program executed by the CPU.

  The ECU 3 is provided in a steering column connected to a steering wheel, and a steering angle sensor 5 for acquiring a steering angle MA, a yaw rate sensor 7 for acquiring a yaw rate YR of the vehicle, a lateral acceleration sensor 9 for acquiring a lateral acceleration G of the vehicle, State quantity acquisition means such as a vehicle speed sensor 11 for acquiring the vehicle speed V, a gear ratio sensor 13 for acquiring the steering gear ratio NG of the vehicle, and a depression amount sensor 15 for obtaining the depression amount of the accelerator are connected. The steering gear ratio is a reduction ratio when the rotation of the steering wheel is reduced in order to reduce the operation force of the steering wheel. The wheel base L of the vehicle is stored in advance in the ROM of the ECU 3, and the value of the wheel base L is obtained from this ROM.

The ECU 3 stores the steering angle MA from the steering angle sensor 5, the yaw rate YR from the yaw rate sensor 7, the vehicle speed V from the vehicle speed sensor 11, the steering gear ratio NG from the gear ratio sensor 13, and stored in advance. Based on the vehicle wheel base L, the vehicle stability factor Kν (s ² / m ² ) is calculated by the following equation (1).

Stability factor Kν =
1 / V ² × (V / (YR × L × NG / MA) -1) × 10 ⁻² (1) Equation In general, as the value of the stability factor Kν increases, the tendency of the vehicle to understeer increases. On the other hand, when the value of the stability factor Kν decreases, the vehicle's over-steering tendency increases.

  Further, the ECU 3 calculates an ascending gradient and a descending gradient (change amount per unit time, for example, per second) of the stability factor Kν based on the stability factor Kν calculated by the above equation (1).

  An engine control unit 17 and a transmission control unit 19 are connected to the ECU 3. The engine control unit 17 increases or decreases the output of the engine 21 based on a control signal from the ECU 3. The transmission control unit 19 controls the transmission 23 interposed between the engine 21 and the propeller shaft and the like based on a control signal from the ECU 3, and torque transmitted from the engine 21 to the propeller shaft and the like via the transmission 23. Change the transmission rate.

  Next, a control method of the turning control device 1 will be described.

  FIG. 2 is a flowchart showing a control process of the turning control device 1 according to the embodiment of the present invention. The control process shown in FIG. 2 is started by closing the ignition switch, and is repeatedly executed at predetermined time intervals.

  First, the ECU 3 has a steering angle MA from the steering angle sensor 5 of a predetermined value or more (for example, a steering angle of 50 deg or more) and a vehicle speed V from the vehicle speed sensor 11 of a predetermined value or more (for example, a vehicle speed of 50 km / h or more). Yes, it is determined whether the vehicle is turning (S100). Note that the ECU 3 may determine that the vehicle is turning when the lateral acceleration from the lateral acceleration sensor 9 is equal to or greater than a predetermined value. Next, when the ECU 3 determines that the vehicle is in a turning state, the depression amount from the depression amount sensor 15 is equal to or greater than a predetermined value, and the accelerator is depressed (for example, the slot valve opening is 50% or more, etc.) It is determined whether it is in a large state (S110). Thereafter, when the ECU 3 determines that the accelerator is depressed, it determines whether or not the rising gradient of the stability factor Kν is equal to or greater than a predetermined value (for example, 0.15 / sec or more) (S120). When the ECU 3 determines that the rising gradient of the stability factor Kν is equal to or greater than a predetermined value (ΔT shown in FIG. 3A) and the vehicle has a large under-steering tendency, the ECU 3 transmits a control signal to the engine control unit 17 to 21 is reduced (S130). FIG. 3A is a diagram showing a state in which the vehicle is in a turning state and the stability factor Kν increases. FIG. 3B, which will be described later, is a diagram showing a state in which the gradient of the stability factor Kν has become gentle under the control of the turning control device 1.

  When the output of the engine 21 is reduced by the engine control unit 17, the acceleration G of the vehicle decreases from the state shown in FIG. 4A to the state shown in FIG. 4B, for example. As a result, the rising gradient of the stability factor Kν becomes gentle (FIG. 3B), and understeering of the vehicle is suppressed (S140). 4A is a diagram showing the acceleration G of the vehicle when the accelerator is depressed in a turning state, and FIG. 4B is a diagram when the output of the engine 21 is reduced by the turning control device 1. It is a figure which shows the acceleration G of a vehicle. The understeering of the vehicle refers to a steering characteristic in which the front tire causes a side slip and the track of the vehicle swells outward as the speed increases when the vehicle is making a large turn at a certain steering wheel angle.

  As described above, when the ECU 3 determines that the stability factor Kν is equal to or greater than the predetermined value and the vehicle has a large tendency to understeer, the output of the engine 21 is reduced. As a result, the rising gradient of the stability factor Kν becomes a gentle state, the understeering of the vehicle is suppressed, and the stability of the vehicle is improved. In addition, since understeering is suppressed near the turning limit, it is possible to improve the operation feeling of the vehicle without giving the driver a feeling of discomfort such as not being able to step on the accelerator or turning the vehicle. . That is, the operability and stability of the vehicle can be improved.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  For example, in (S130) of the above embodiment, the ECU 3 reduces the output of the engine 21 when it is determined that the vehicle has a large tendency to understeer, but transmits a control signal to the transmission control unit 19 to transmit the transmission 23. The torque transmission rate may be reduced. Thereby, the same effect as the case where the output of the engine 21 is reduced as described above can be obtained while maintaining the output of the engine 21 constant.

  In (S120) of the above embodiment, the ECU 3 determines whether or not the rising gradient of the stability factor Kν is greater than or equal to a predetermined value, but the ECU 3 determines that the falling gradient of the stability factor Kν is equal to or larger than a predetermined value. It may be determined whether or not there is. When the ECU 3 determines that the descending gradient of the stability factor Kν is equal to or greater than the predetermined value and the vehicle has a large over-steering tendency, the ECU 3 transmits a control signal to the engine control unit 17 to reduce the output of the engine 21 (S130). As a result, the descending gradient of the stability factor Kν becomes a gentle state, and oversteering of the vehicle is suppressed. Note that oversteering refers to a characteristic of the steering in which the rear tire slips and the vehicle cuts inward as the speed increases when the vehicle is making a large turn at a certain steering wheel angle.

  Further, in (S130) of the above-described embodiment, when the ECU 3 determines that the vehicle's under steering tendency is large, the vehicle speed V is decreased, the yaw rate YR is increased, the steering angle MA is decreased, and / or the steering gear ratio is increased. The behavior of the vehicle may be controlled to increase NG. That is, any vehicle control can be applied as long as the stability factor Kν is controlled to decrease.

  The present invention can be used for a turning control device for a vehicle. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is the schematic of the system configuration | structure which shows the turning control apparatus which concerns on one Example of this invention. It is a flowchart which shows the control processing of the turning control apparatus which concerns on one Example of this invention. (A) It is a figure which shows the state which a stability factor rises. (B) It is a figure which shows the state from which the gradient of the stability factor became loose by control of the turning control apparatus. (A) It is a figure which shows the acceleration of a vehicle when an accelerator is stepped on in the turning state. (B) It is a figure which shows the acceleration of a vehicle when the output of an engine is reduced by the turning control apparatus.

Explanation of symbols

1 turning control device 3 ECU
DESCRIPTION OF SYMBOLS 5 Steering angle sensor 7 Yaw rate sensor 9 Lateral acceleration sensor 11 Vehicle speed sensor 13 Gear ratio sensor 15 Depression amount sensor 17 Engine control part 19 Transmission control part 21 Engine 23 Transmission

Claims (2)

State quantity acquisition means for acquiring the state quantity of the vehicle;
A turn control device comprising stability factor calculation means for calculating a stability factor of the vehicle in a turning state based on the state quantity of the vehicle acquired from the state quantity acquisition means,
Based on the stability factor calculated by the stability factor calculation means, a gradient calculation means for calculating the amount of change per unit time of the stability factor;
Control means for controlling the behavior of the vehicle such that the amount of change per unit time calculated by the gradient calculating means is less than or equal to a predetermined value;
Determination means for determining the accelerator depression state,
The slope calculating means calculates the amount of change per unit time of the stability factor when the accelerator depression state becomes a predetermined state.
The control means controls the behavior of the vehicle so that the amount of change is less than a predetermined value when the amount of change is equal to or greater than a predetermined value.
A turning control device characterized by that. The turning control device according to claim 1 ,
The vehicle state quantity includes a speed of the vehicle, a yaw rate of the vehicle, a steering angle of the vehicle, a steering gear ratio of the vehicle, and a wheel base of the vehicle.

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