JPS60113710A - Cornering sensor for car - Google Patents

Abstract

PURPOSE:To detect the turning state of a car without using a steering-angle sensor by judging the turning state of the car by obtaining the difference of the number of revolution between right and left wheels from the output of a revolution number sensor for detecting the number of revolution of the wheels. CONSTITUTION:Right and left revolution number sensor 6a and 6b detect the number of revolution of the right and left wheels among front and rear-wheels 1a-1d. After the detection by the sensors 6a and 6b is performed, the difference of the number of revolution between the right and left wheels is calculated in the substraction circuit 8 of a controller 7, and the average value of the number of revolution of the right and left wheels is calculated in a calculation circuit 9, and the radius R of turn of a car is calculated in a calculation circuit 10, and at the same time, a car speed V is obtained in a calculation circuit 11. In a calculation circuit 12, the centrifugal acceleration speed of the car is obtained, and compared with a set value in a comparator 13, and in a calculation circuit 15, the magnitude of the car acceleration speed is obtained from the car speed V, and compared with a set value in a comparator 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cornering sensor for an automatic 11-turn system that detects the turning state of an automobile.

[Prior art]

In general, the characteristics required for vehicle suspension are:
1. Longitudinal stability and riding comfort. By the way, when a vehicle turns, centrifugal force acts on the vehicle, causing the vehicle to move from side to side, causing so-called rolling. Also, when accelerating suddenly or braking suddenly, a large accelerating force or braking force acts on the vehicle, causing the vehicle to move back and forth. It is known that the vehicle may lean, or so-called pitching, and in such a case, a sudden change in posture occurs, which significantly changes the vehicle's dynamic characteristics and increases the psychological burden on the driver. It is something.

Conventionally, as a method to eliminate such problems,
Regarding rolling, for example, Utility Model Application No. 56-14710
As shown in Publication No. 7, the damping force of the variable damper provided in the suspension is adjusted by detecting the conditions under which a roll speed exceeding a predetermined value corresponding to changes in cardiac acceleration when the vehicle turns is generated based on the steering angle and vehicle speed. For pinoting, the damping force of the variable damper is increased by detecting the amount of operation of the accelerator pedal or brake pedal, thereby suppressing the occurrence of pitching.

However, in this conventional method, two types of sensors are required to suppress vehicle rolling, and the control thereof is complicated.Also, two types of sensors are required to suppress vehicle pitching. There was a problem in that it was necessary to provide several sensors, making the structure very complicated. In addition, since a steering angle sensor is used, the sensor must be installed around the steering wheel, which has a narrow space, and the installation work is very complicated. There was a problem in that the adjustment work to adjust the relationship between the corner and the turning position of the vehicle (flea) was very complicated.

[Purpose of the invention]

In view of these problems, the present invention aims to provide a cornering sensor for an automobile that can determine the turning state of an automobile with a single type of sensor without using a steering angle sensor, and is easy to adjust and assemble. It is something.

[Structure of the invention]

Therefore, the present invention provides a rotation speed sensor that detects the rotation speed of either the front or rear wheels of the vehicle, and calculates the rotation speed difference between the left and right wheels based on the outputs of both sensors to determine the turning state of the vehicle. It is designed to determine.

〔Example〕

Prior to detailed description of the present invention, theoretical matters necessary for understanding the present invention will be explained.

First, we will explain the reason why the turning condition of a car, especially the turning speed, can be determined from the rotation speed of the left and right wheels using Figure 1 (C1). In the figure, nl.

n2 is the rotation speed of the left and right wheels, n3 is the rotation speed at the center of the vehicle, K is the distance between the king pins, and θ is the turning angle of the vehicle.

Now, assuming that the vehicle has turned by an angle θ during time t, and assuming that the distance g between the boiler height L and the rear wheels and the vehicle center of gravity are small compared to the turning radius R, the following relationship holds true. .

...(2) If we transform this equation (2), we get --- (n 2 + n 1 ) ・°・ R= □ n 2 - nl ... (3) From this equation (3), we can see that the left and right Rotation speed of the wheel n1. Fl R was detected while turning from n2. Since the wheels experience side slip during normal driving, if the turning radius R determined from the rotational speed is corrected using the correction coefficient a, taking into account the side slip angle of the front and rear wheels of the vehicle, The turning radius R at the actual vehicle center of gravity position is determined by the following equation (4).

-(n 2 + n 1) R=a □ ...(4) n2 nl Next, the reason why rolling and pitching of the vehicle can be suppressed and controlled depending on the turning state of the vehicle will be explained using FIG. Figure 1 (al) (bl conceptually shows the state of the vehicle when turning. In the figure, ■ is the vehicle speed, m is the vehicle weight, F is the centrifugal force, Fl is the vertical component of the centrifugal force F, and R is the turning radius, k and C are the spring constant of the suspension and the damping coefficient of the damper, and X is the amount of vertical displacement of the vehicle body.

The cardiac acceleration when turning a vehicle is generally F/m = v2
/R. Then, the change in cardiac acceleration is expressed by the following equation.

(5) Here, in equation (5), clv/dt is the acceleration of the vehicle, and dR/dt is the rate of change in the turning radius.

The equation of motion of the suspension is expressed by the following equation.

・・・・・・(6) ``2 notation + 51. From (6), the center acceleration is a function of the roll speed dx / dt, and therefore, the vehicle speed, vehicle acceleration, turning radius, and rate of change of the turning radius can be estimated. By doing so,
It is possible to determine the spring constant k and the damping coefficient C to suppress rolling of the vehicle.

Furthermore, since sudden acceleration or sudden braking can be determined based on the number of rotations of the wheels, it is possible to suppress the pitching of the vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

2 and 3 show a variable damper control device with a cornering sensor for a motor vehicle according to an embodiment of the present invention.

In FIG. 2, 1a to 1d are the front wheels and rear wheels of a car,
2a to 2d are variable dampers 3a to 3d and spring members 43 to 4
d, which supports the front and rear wheels 1a to 1d on the vehicle body; 5a to 5d are variable dampers 3a;
~3d actuator for increasing the damping force, 6a,
6b is a left and right rotational speed sensor for detecting the rotational speed of one of the front wheels or rear wheels 1a to 1d, one of the left and right wheels;
receives the outputs of the two sensors 6a and 6b, determines the turning state of the vehicle from the rotational speed difference between the left and right wheels, outputs a control signal to the actuators 5a to 5d, and controls the actuators 5a to 5d.
This is a controller that drives and controls a to 5d.

Further, FIG. 3 shows a more detailed configuration of the controller 7, and in the figure, 8 is a rotation speed sensor 6a.

6b is a subtraction circuit that calculates the difference n2-n1 between the re-outputs, and 9 is the average value (n2+nt) of the re-outputs of the rotational speed sensors 6a and 6b.
The arithmetic circuit and IO that calculates /2 receives the outputs of both circuits 8.9 and calculates a (((n2 +n1)/2)-K)/(n
A calculation circuit 19 calculates the turning radius R using the formula 2 to rz); 19 is a determination circuit configured by the above circuits 8 to 10 and determines the turning state of the automobile; 11 receives the output of the average value calculation circuit 9; , πr(n1+n2), where r is the radius of the wheel. 12 is a turning radius and vehicle speed recalculation circuit 1
A calculation circuit receives the output of 0.11 and calculates the cardiac acceleration F/m of the vehicle using the formula V2/R, and 13 is a comparison circuit that compares the output of the calculation circuit 12 and the output of the set value generation circuit 14. 15 is an arithmetic circuit that calculates the magnitude of vehicle acceleration l v l (-ldv/dtl) from the output of the vehicle speed arithmetic circuit 11; The comparator 18 for comparison is an OR circuit that outputs the outputs of both the comparators 13 and 16, and the "1" signal of the OR circuit 18 is applied as a control signal to the actuators 5a to 5d, thereby controlling the damper. 3
The damping force of a to 3d is adjusted to be high (
However, only one actuator 5a and one damper 3a are shown in FIG. 3).

Next, the operation will be explained.

In this device, the rotation speed n1 of the left and right wheels. When n2 is detected by the rotational speed sensors 6a and 6b, the subtraction circuit 8 calculates the rotational speed difference n2-nl between the left and right wheels, and the arithmetic circuit 9 calculates the average rotational speed of the left and right wheels (n2→-n 1)/ 2 is calculated, and the difference n2 - n1 of this rotation speed and the average value (n2 + ni)
/2, the turning radius R of the vehicle is calculated in the arithmetic circuit 10, and at the same time, the vehicle speed is determined in the arithmetic circuit 11. When the turning radius R and vehicle speed of the vehicle are determined, the arithmetic circuit 12 determines the cardiac acceleration F/m of the vehicle, and this cardiac acceleration F/m
For example, the comparator 13 compares it with a set value. Also, the arithmetic circuit 15
Then, the magnitude 101 of the vehicle acceleration is determined from the vehicle speed ■, and the magnitude 1/1 of this vehicle acceleration is compared with a set value in the comparator 16.

When the turning radius R of the vehicle is small and rolling occurs in the vehicle, the output of the comparator 13 becomes "1", and this "1" signal is used as a control signal to control the actuator 5.
a to 5d, thereby increasing the damping force of the dampers 3a to 3d and suppressing rolling of the vehicle. When the vehicle completes a turn, the output of the comparator 13 becomes “0”.
Therefore, the generation of the control signal is stopped, and the damping force of the dampers 3a to 3d returns to the normal low state.
Vehicle comfort is guaranteed.

Furthermore, when sudden braking or acceleration occurs, the magnitude of the vehicle acceleration Iol increases, so the output of the comparator 16 becomes "1", and this "1" signal is applied as a control signal to the actuators 5a to 5d. Therefore, in this case as well, the damping force of the dampers 3a to 3d becomes high, thereby suppressing pitching of the vehicle.

In the device of this embodiment as described above, both rolling and pitching of the vehicle can be controlled using one cornering sensor. Furthermore, this cornering sensor is constructed using a rotation speed sensor, and is easier to assemble and adjust than when a steering angle sensor is used. Furthermore, since the turning state can be detected with one type of sensor, the structure is simpler and the cost is lower than the conventional case where the turning state is detected using a steering angle sensor and a vehicle speed sensor.

By the way, in the above embodiment, a case has been described in which the controller 7 is configured as a hardware, but the controller 7 may also be configured as a software, and FIG. 4 shows the flow of arithmetic processing when the controller 7 is configured as a software. In the figure, 21 is a step for initializing the system, and 22 is a rotation speed sensor 6a.

6b is a step of reading the output, 23 is a step of calculating the rotational speed difference n2-nl between the left and right wheels, 24 is a step of calculating the average value of the rotational speeds of the left and right wheels (n2→-rz)/2, and 25 is the above calculation. 26 is a step of calculating the vehicle speed using the formula πr (n2 + n1), and 27 is cardiac acceleration V
Step of calculating 2/R, step of determining whether the magnitude of cardiac acceleration lv2/Rl fitted into 2B is larger than a set value, step 29 of calculating vehicle acceleration v (=dv/dt), 30 is a determination step for determining whether the acceleration magnitude 1: Jl is larger than a set value; 31 is a step for generating a control signal for the actuators 5a to 5d to increase the damping force of the dampers 3a to 3d; and 32 is a step for increasing the damping force of the dampers 3a to 3d. This is a step in which the generation of the control signal is stopped to maintain the damping force of the dampers 3a to 3d in a low state.

Note that since the operation of this embodiment is easily understood, its explanation will be omitted.

In the above embodiment, the variable damper was controlled in two stages, but it is also possible to determine the optimum damping coefficient for centrifugal force from the equation of motion of the suspension in advance, and then continuously control the damping force of the damper. You can also do this.

Furthermore, in the above embodiment, the case where the automotive cornering sensor of the present invention is used to control the variable damper of the suspension has been described, but the automotive cornering sensor of the present invention may be used to control the vehicle in accordance with the turning state of the vehicle. For example, it can also be used for control other than this, for example, controlling the operating force of power steering.

〔Effect of the invention〕

As described above, according to the cornering sensor for a vehicle according to the present invention, the rotation speed of either the front or rear wheels is detected, and the turning state of the vehicle is determined from the difference in rotation speed between the left and right wheels. Therefore, the turning state of the automobile can be detected without using a conventional steering angle sensor, the assembly and adjustment work is easy, the turning state can be detected with one type of sensor, and the structure wJ is simple and simple. It has the effect of being inexpensive.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a vehicle for explaining theoretical matters necessary for understanding the present invention, and FIG. 2 is a schematic diagram of a control device for a variable damper equipped with an automotive cornering sensor according to an embodiment of the present invention. 3 is a more detailed configuration diagram of the above-mentioned apparatus, and FIG. 4 is a flowchart 1 in another embodiment of the present invention.
・It is a figure showing. 1a to 1d...front and rear wheels, 6a, 6b...rotation speed sensor, 7...controller 1-roller (discrimination means). Patent application - Person: Toyo Kogyo Co., Ltd. (1 other person) Representative Patent attorney Ken Hayase -

Claims (1)

[Claims] (1) Left and right rotational speed sensors that detect the rotational speed of either the front or rear wheels of the vehicle, and a system that receives output signals from both sensors and calculates the difference between the dual-use force signals. 21. A turning sensor for an automobile, characterized in that it is provided with separate means for determining the turning state of the automobile.