JP2006015797A - Reaction control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a good steering feeling by adjusting a secondary reaction component set according to the change rate of vehicle behavior, according to the grade of the vehicle behavior. <P>SOLUTION: This reaction control device for controlling a reaction component to be applied to a steering wheel operated by a vehicle driver is provided with a yaw rate sensor 18 for detecting the yaw rate of a vehicle, a primary reaction component control means (a yaw rate correction current computing part) 36 for setting a primary reaction component larger as the detection value of the yaw rate sensor 18 becomes larger, and a secondary reaction component control means 37 for setting the secondary reaction component larger as the detection value of the yaw rate sensor 18 becomes larger. The reaction component includes the primary reaction component and the secondary reaction component. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reaction force control device for controlling a reaction force component to be applied to an operator in a vehicle steering system.

  An electric power steering device is known as a vehicle steering device. In the electric power steering apparatus, a steering shaft coupled to a steering wheel and a steering mechanism that steers the steered wheels are mechanically coupled, and an electric motor for assisting a steering force is linked to the steering mechanism. In general, the drive torque command value (drive current value) of the electric motor is controlled such that the auxiliary steering force increases as the steering torque acting on the steering shaft increases.

  Further, in this electric power steering device, in order to suppress the irregular behavior of the vehicle due to disturbance, the vehicle behavior (for example, yaw rate) is detected by the detecting means, and the driving torque correction value in the direction to cancel the vehicle behavior is calculated. In some cases, the motor is controlled by subtracting the drive torque correction value from a base drive torque command value set according to the steering torque to obtain a drive torque command value (see, for example, Patent Document 1). When configured in this way, even when a yaw rate is generated during normal turning, the driving torque correction value is generated in a direction to suppress these, that is, in a direction to return the vehicle to a straight traveling state. Therefore, it can be said that the drive torque correction value is a reaction force component with respect to the assist force.

Furthermore, the electric power steering device takes into account the temporal change in vehicle behavior (yaw rate and lateral acceleration), that is, the reaction force component calculated based on the rate of change, thereby suppressing the response of behavior suppression to the change in vehicle behavior. There is also an apparatus in which the height is increased (see, for example, Patent Document 2).
Japanese Patent No. 3229074 Japanese Patent No. 3110891

However, conventionally, for example, when calculating a reaction force component according to the rate of change of the yaw rate (differential value of the yaw rate), the control amount (differential control amount) corresponding to the differential value of the yaw rate is the same regardless of the magnitude of the yaw rate. Therefore, in some cases, the differential control becomes excessive and the steering feeling may be deteriorated, and there is room for improvement.
For example, with the differential control amount optimally set in a region where the yaw rate is high (such as during turning), the differential control is too effective in a region where the yaw rate is low (such as when going straight), and there is an excessive reaction force component corresponding to the rate of change in yaw rate. Steering feeling is good.
Therefore, the present invention makes it possible to obtain a favorable steering feeling by making the secondary reaction force component set according to the change rate of the vehicle behavior variable according to the magnitude of the vehicle behavior. A control device is provided.

In order to solve the above-mentioned problems, the invention according to claim 1 is a method for controlling a reaction force component to be applied to an operator (for example, a steering wheel 3 in an embodiment described later) operated by a vehicle driver. In the force control device, vehicle behavior detection means (for example, yaw rate sensor 18 in the embodiment described later) for detecting the behavior of the vehicle (for example, yaw rate in the embodiment described later), and detection value of the vehicle behavior detection means. Is larger, the primary reaction force component control means (for example, yaw rate correction current calculation in the embodiment described later) is set to increase the primary reaction force component (for example, the primary yaw rate reaction force correction current Im2a in the embodiment described later). Part 36) and the second reaction force component (for example, an embodiment to be described later) as the rate of change of the detection value of the vehicle behavior detecting means increases The secondary reaction force component control means (for example, to be described later) that sets the secondary reaction force component larger as the secondary yaw rate reaction force correction current Im2b) is set larger and the detection value of the vehicle behavior detection means is larger. Secondary reaction force component control means 37) in the embodiment, wherein the reaction force component includes the primary reaction force component and the secondary reaction force component.
By configuring in this way, the secondary reaction force component can be made variable according to the magnitude and rate of change of the vehicle behavior. Even if the rate of change of the vehicle behavior is the same, the higher the vehicle behavior, the greater the secondary reaction force component. The force component can be set large.

  According to the first aspect of the present invention, the differential control amount of the vehicle behavior can be set larger in the region where the vehicle behavior is large (such as during turning) than in the region where the vehicle behavior is small (such as when going straight). When the change rate of the vehicle behavior is the same, the secondary reaction force component can be set larger in the region where the vehicle behavior is larger than in the region where the vehicle behavior is small. As a result, when the vehicle behavior is large, the response of the behavior suppression to the change in the vehicle behavior can be improved, and when the vehicle behavior is small, the secondary reaction force component can be prevented from being excessive, Steering feeling can be optimized over a wide range from a region where the vehicle behavior is small to a large region.

Embodiments of a reaction force control apparatus according to the present invention will be described below with reference to the drawings of FIGS. In the following embodiments, the present invention will be described in an aspect applied to an electric power steering device.
First, the configuration of the electric power steering apparatus according to the first embodiment will be described with reference to FIG. The electric power steering apparatus includes a manual steering force generating mechanism 1, and the manual steering force generating mechanism 1 includes a connecting shaft 5 in which a steering shaft 4 integrally coupled to a steering wheel (operator) 3 has a universal joint. And is connected to the pinion 6 of the rack and pinion mechanism. The pinion 6 meshes with a rack 7a of a rack shaft 7 that can reciprocate in the vehicle width direction, and left and right front wheels 9, 9 as steered wheels are connected to both ends of the rack shaft 7 via tie rods 8, 8. ing. With this configuration, a normal rack and pinion type steering operation can be performed when the steering wheel 3 is steered, and the direction of the vehicle can be changed by turning the front wheels 9 and 9. The rack shaft 7 and the tie rods 8 and 8 constitute a steering mechanism.

  In addition, an electric motor 10 that supplies auxiliary steering force for reducing the steering force generated by the manual steering force generation mechanism 1 is disposed coaxially with the rack shaft 7. The auxiliary steering force supplied by the electric motor 10 is converted into thrust through a ball screw mechanism 12 provided substantially parallel to the rack shaft 7 and is applied to the rack shaft 7. For this purpose, a driving-side helical gear 11 is integrally provided on the rotor of the electric motor 10 through which the rack shaft 7 is inserted, and a driven-side helical gear 13 that meshes with the driving-side helical gear 11 is provided at one end of the screw shaft 12a of the ball screw mechanism 12. The nut 14 of the ball screw mechanism 12 is fixed to the rack 7.

The steering shaft 4 is provided with a steering speed sensor 15 for detecting the steering speed (angular speed) of the steering shaft 4, and is provided in a steering gear box (not shown) that houses the rack and pinion mechanism (6, 7a). Is provided with a steering torque sensor (steering torque detecting means) 16 for detecting a steering torque acting on the pinion 6. The steering speed sensor 15 outputs an electrical signal corresponding to the detected steering speed, and the steering torque sensor 16 outputs an electrical signal corresponding to the detected steering torque to the steering control device 20, respectively.
Further, a yaw rate sensor (yaw rate detecting means) 18 for detecting the yaw rate of the vehicle and a vehicle speed sensor (vehicle speed detecting means) 19 for outputting an electric signal corresponding to the vehicle speed are attached at appropriate positions of the vehicle body. The yaw rate sensor 18 outputs an electric signal corresponding to the detected yaw rate, and the vehicle speed sensor 19 outputs an electric signal corresponding to the vehicle speed to the steering control device 20, respectively. In this embodiment, the vehicle behavior is detected from the yaw rate, and the yaw rate sensor 18 constitutes a vehicle behavior detection sensor that detects the behavior of the vehicle.

  The steering control device 20 determines a target current to be supplied to the electric motor 10 based on a control signal obtained by processing input signals from these sensors 15, 16, 18, and 19, and the electric motor 10 through the drive circuit 21. To control the output torque of the electric motor 10 and the operation assisting force in the steering operation.

Next, with reference to the control block diagram of FIG. 2, the current control for the electric motor 10 in this embodiment will be described.
The steering control device 20 includes a base current determination unit 31, an inertia correction unit 32, and a reaction force correction unit (reaction force component control means) 33.
The base current determination unit 31 determines a base current value corresponding to the steering torque and the vehicle speed with reference to a base current table (not shown) based on the output signals of the steering torque sensor 16 and the vehicle speed sensor 19. Here, the base current table is set so that the base current increases as the steering torque increases, and the base current decreases as the vehicle speed increases.
In the inertia correction unit 32, inertia mass compensation of the electric motor 10 is performed on the base current determined by the base current determination unit 31.

The reaction force correction unit 33 subtracts a correction current corresponding to the reaction force component from the current after inertia mass compensation, calculates a target current for the electric motor 10, and outputs the target current to the drive circuit 21. The drive circuit 21 controls the supply current to the electric motor 10 to be a target current, supplies the electric current to the electric motor 10, and controls the output torque of the electric motor 10.
Therefore, in the electric power steering apparatus of this embodiment, the correction current set in the reaction force correction unit 33 can be referred to as a reaction force component for the steering assist force, and the base current set in the base current determination unit 31 is this It can be said that the steering assist force before canceling the reaction force component.
The reaction force correction unit 33 includes a damper correction unit 34 and a yaw rate reaction force correction unit 35.
The damper correction unit 34 calculates a first reaction force correction current based on the steering speed, and subtracts the first reaction force correction current from the current after the inertial mass compensation.

The yaw rate reaction force correction unit 35 calculates the second reaction force correction current Im2 based on the yaw rate, and subtracts the second reaction force correction current Im2 from the current output from the damper correction unit 34 to calculate the target current. .
The second reaction force correction current Im2 basically includes a primary yaw rate reaction force correction current (primary reaction force component) Im2a calculated based on the yaw rate detected by the yaw rate sensor 18, the yaw rate detected by the yaw rate sensor 18, and It is obtained by adding a secondary yaw rate reaction force correction current (secondary reaction force component) Im2b calculated based on the rate of change (differential value). Hereinafter, calculation of the second reaction force correction current Im2 in the yaw rate reaction force correction unit 35 will be described in detail.

  A yaw rate correction current calculation unit (primary reaction force component control means) 36 calculates a primary yaw rate reaction force correction current Im2a with reference to a yaw rate correction current table (not shown) based on the output signal of the yaw rate sensor 18. . Here, the yaw rate correction current table is set so that the primary yaw rate reaction force correction current Im2a increases as the yaw rate increases (in other words, the primary reaction force component increases).

Further, the signal differentiation means 38 performs differentiation processing on the output signal of the yaw rate sensor 18. A signal obtained by this differentiation process (hereinafter referred to as a differential signal) corresponds to a temporal change in yaw rate (in other words, a rate of change in yaw rate).
Then, the yaw rate differential correction current calculation unit 39 calculates a reference yaw rate differential correction current (reference secondary reaction force component) Im2B based on the differential signal with reference to a yaw rate differential correction current table (not shown). Here, the yaw rate differential correction current table is such that the reference yaw rate differential correction current Im2B increases as the yaw rate increases (in other words, the reference secondary reaction force component increases as the vehicle behavior change rate increases). Is set).

  Further, the ratio R corresponding to the magnitude of the yaw rate is calculated with reference to the yaw rate ratio table 40 based on the output signal of the yaw rate sensor 18. In the yaw rate ratio table 40 in this embodiment, the ratio R is set smaller than “1” when the yaw rate is “0”, and the ratio R gradually increases as the yaw rate increases, and the yaw rate is predetermined. The ratio R is set to be “1” and constant when the value is exceeded.

The product (Im2B · R) obtained by multiplying the reference yaw rate differential correction current Im2B calculated by the yaw rate differential correction current table 39 by the ratio R calculated from the yaw rate ratio table 40 is referred to as a secondary yaw rate reaction force correction current Im2b. (Im2b = Im2B · R).
Next, the primary yaw rate reaction force correction current Im2a and the secondary yaw rate reaction force correction current Im2b are added together to obtain a second reaction force correction current Im2 (Im2 = Im2a + Im2b).

  In this embodiment, the part that performs a series of processes for calculating the secondary yaw rate reaction force correction current Im2b from the detection value of the yaw rate sensor 18 constitutes the secondary reaction force component control means 37 (see FIG. 2). Therefore, the secondary reaction force component control means 37 increases the secondary reaction force component (secondary yaw rate reaction force correction current Im2b) as the change rate (differential value) of the detection value of the vehicle behavior detection means (yaw rate sensor 18) increases. It can be said that it is a control means that sets the secondary reaction force component (secondary yaw rate reaction force correction current Im2b) larger as the detection value of the vehicle behavior detection means (yaw rate sensor 18) is larger. The yaw rate ratio table 40 can be said to be a changing means for changing the secondary reaction force component (secondary yaw rate reaction force correction current Im2b) according to the magnitude of the vehicle behavior (yaw rate).

Since the ratio R is set to a larger value as the yaw rate is larger in this way, and the secondary yaw rate reaction force correction current Im2b is set by multiplying the ratio R by the reference yaw rate differential correction current Im2B, the ratio Y depends on the yaw rate. Thus, the secondary yaw rate reaction force correction current Im2b can be made variable, and the secondary yaw rate reaction force correction current Im2b can be set larger as the yaw rate increases even if the differential value of the yaw rate is the same.
That is, in a region where the yaw rate is large (such as during turning), the yaw rate differential control amount can be set larger than in a region where the yaw rate is small (such as when traveling straight). As a result, if the yaw rate differential value is the same, In the region where the yaw rate is large, the reaction force component (that is, the secondary yaw rate reaction force correction current Im2b) based on the differential value of the yaw rate can be set larger than the region where the yaw rate is small.
As a result, for example, when the yaw rate is large, such as when the vehicle is turning, it is possible to improve the response of the behavior suppression with respect to the yaw rate change. The steering feeling can be optimized over a wide range from a region with a low yaw rate to a region with a large yaw rate.

[Other Examples]
The present invention is not limited to the embodiment described above.
For example, in the embodiment described above, the behavior of the vehicle is detected from the yaw rate, but the vehicle behavior can also be detected from the lateral acceleration. Therefore, according to the present invention, a lateral acceleration that is a vehicle behavior is detected by a lateral acceleration sensor (lateral acceleration detection means, vehicle behavior detection means), and a series of processes performed on the detection value of the yaw rate sensor 18 in the above-described embodiment. The same processing can be realized by performing the same processing as for the detection value of the lateral acceleration sensor.

Further, the reaction force control device according to the present invention is not limited to the application to the electric power steering device of the above-described embodiment, but is a steering device for vehicles (SBW) of a steering-by-wire system, an active steering device, The present invention can also be applied to a vehicle steering device for a system and a vehicle steering device (VGS) for a variable gear ratio steering system.
Note that the steering-by-wire system means that the operating element and the steering mechanism are mechanically separated, a reaction force motor that applies a reaction force to the operating element, and a steering wheel provided in the steering mechanism. The steering system includes a steering motor that generates a force for turning the vehicle.
The active steering system is a steering system that controls the front wheel steering angle and the rear wheel steering angle in accordance with the steering operation of the driver and the motion state of the vehicle.
The variable gear ratio steering system is a steering system in which the steering gear ratio can be changed according to the magnitude of the steering angle.

It is a lineblock diagram of an electric power steering device provided with a reaction force control device concerning this invention. It is a block diagram of the current control with respect to the electric motor of the said electric power steering device.

Explanation of symbols

3 Steering wheel (operator)
18 Yaw rate sensor (vehicle behavior detection means)
36 Yaw rate correction current calculation unit (primary reaction force component control means)
37 Secondary reaction force component control means

Claims (1)

In a reaction force control device that controls a reaction force component to be applied to an operator operated by a driver of a vehicle,
Vehicle behavior detecting means for detecting the behavior of the vehicle;
Primary reaction force component control means for setting a larger primary reaction force component as the detection value of the vehicle behavior detection means is larger;
The secondary reaction force component is set such that the secondary reaction force component is set to be larger as the change rate of the detection value of the vehicle behavior detection means is larger, and the secondary reaction force component is set to be larger as the detection value of the vehicle behavior detection means is larger. Control means;
The reaction force component includes the primary reaction force component and the secondary reaction force component.

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