JPS61295114A - Suspension controller - Google Patents

Abstract

PURPOSE:To make improvements in steering stability at the time of driving on a mountain pass or the like, by calculating a pass index from a driving state, while constituting a controller so as to control an opening area variable solenoid valve of an orifice for damping force control use with an output current corresponding to this index. CONSTITUTION:Detection force of a steering angle sensor 40 is inputted into a central processing unit 51 of an electronic controller 51 via phase judging circuit 45. A car speed also is inputted into this CPU 51 which processes it according to the specified program and calculates a pass index K. Next, this pass index K is multiplied by a constant A whereby an output current (i) is found, outputting this output current (i) to a solenoid driving circuit 61. Accordingly, a solenoid 30 controls an opening sectional area of a variable orifice 29 to come into the state conformed to pass drivingness. With this constitution, steering stability at the time of driving on a mountain pass.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a suspension control device that controls the damping force of a suspension depending on the driving condition of an automobile.

<Conventional technology> Conventionally, the damping force of a vehicle suspension is normally controlled according to the vehicle speed, and the damping force is small in the low speed range.
Additionally, the damping force is controlled to increase in the high-speed range.

<Problems to be solved by the invention> However, conventional suspension damping force control is only aimed at improving high-speed stability;
For example, the damping force is not made variable depending on the driving conditions, such as on mountain roads or in urban areas, so when driving on mountain roads, when the steering wheel is frequently operated from side to side, the car may sway, There was a problem that the steering stability could be impaired due to tilting.

<Means for Solving the Problems> The present invention automatically determines the driving condition of the automobile and controls the damping force of the suspension according to the driving condition, and uses a variable orifice that changes the damping force of the suspension. an electromagnetic means for controlling the opening area; a calculation means for calculating a mountain road index according to the driving condition based on the driving condition;
It is constructed by a calculation means for calculating an output current value according to the calculated mountain road index, and a control means for controlling the electromagnetic means based on the calculated output current value.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, the power steering device 10 includes a nozzle shaft 1
It consists of a servo pulp 1) connected to a steering wheel 18 via a link mechanism 8a, and a power cylinder 12 connected to a steering wheel through a circuit linkage, and is capable of applying manual steering torque to the steering wheel IB, as is known in the art. For example, the steering torque increased by the power cylinder 12 is transmitted to the steered wheels.

The suspension for suspending the steering wheel is composed of a shock absorber 21 and a coil spring 22. The cylinder 23 side end of the shock absorber 21 is pivotally supported by a lower control arm, and is slidably fitted into the cylinder 23. The installed piston rod 24 side end is pivotally supported by the vehicle body. The coil spring 22 is connected to the cylinder 23
It is inserted between the shock absorber 21 and the vehicle body to bias the shock absorber 21 in the direction of extension.

The cylinder 23 of the shock absorber 21 is filled with fluid such as oil, and is divided into a -L chamber 26 and a lower chamber 27 by a piston 25. These two chambers 26 and 27 are communicated with each other via a variable orifice 29 whose opening area is controlled by a solenoid valve 28.
9, the opening area is reduced in proportion to the increase in the current value applied to the solenoid 30 of the electromagnetic valve 28.

50 is an electronic control device, and this electronic control device 50 has a microprocessor 51, a writable memory (hereinafter simply referred to as RAM) 52, and a read-only memory (hereinafter simply referred to as ROM) 53 as main components, An interface 60 and a solenoid drive circuit 61 are connected to 51 to control the current applied to the solenoid 24 of the electromagnetic valve 20.

Further, a steering angle sensor 40 is connected to the microprocessor 51 via an interface 47 and a phase determination circuit 45. The steering angle sensor 40 includes a rotary plate 41 fixed on the handle shaft 18a and two photo-ink converters 42.
, 43, such photo ink printers 42, 4a
The steering wheel steering angle θ is detected based on a signal from the steering wheel.

Furthermore, the microprocessor 51 has an interface 47.
A vehicle speed sensor 46 is connected via.

This vehicle speed sensor 46 is composed of a tachometer connected to the output shaft of the transmission, and is adapted to detect the vehicle speed based on the frequency of a pulse signal generated from this vehicle speed sensor 46.

The RAM 52 has a storage area for storing the frequency corresponding to the steering angle θ of the steering wheel, and the RO'M 53 calculates an index K indicating the running state, and applies the voltage to the electromagnetic valve 20 according to this index K. A control program for calculating current is stored.

Figures 4 and 5 show the frequency distribution corresponding to the steering angle θ.When driving on a mountain road, there are many curves, but there are few right angle turns, so the frequency distribution is as shown in Figure 4.When driving on a city road, the frequency distribution is as shown in Figure 4. The frequency distribution is as shown in Figure 5 because most of the vehicles travel straight and there are few curves, but they often turn at right angles at intersections. Therefore, the index (hereinafter referred to as mountain road index) K obtained by executing the control program has a larger value when driving on a mountain road than when driving in a city area.

Next, an example of determining the running state will be explained with reference to the flowchart shown in FIG.

When the vehicle is running, the steering angle signal θ, which changes moment by moment, detected by the steering angle sensor 40 is detected by the phase determination circuit 4.
5 to a counter (not shown), and a vehicle speed signal detected by a vehicle speed sensor 46 is also input to the counter (not shown).

The microprocessor 51 executes a processing operation based on a program at the same time that an interrupt signal is input every predetermined mileage. First, in step 100 of FIG. 6, the steering angle θ stored in the counter is read, and then in step 10.
1, the sampling number counter value n is the set number of times N
compared to

Immediately after the start of running, the number of samplings is small and n<N, so the program proceeds to step 102, where 1 is added to the sampling number counter value n, and then step 1
03, the nth area Mn of the storage area of the RAM 52
The absolute value of the steering angle θ is set to .

When the number of samples n increases and reaches the set number N, the program proceeds from step 101 to step 104, where the cent value of area M2 is transferred to area M1, the cent value of area M3 is transferred to area M2-, . ..., and the absolute value of the latest (nth) steering angle θ is set in the last area MN, thus updating the stored contents. In this state, the sampling number counter value remains n (=N).

In step 105 following step 103 or 104, a sampling number counter value n is initialized in the read counter 1), and in subsequent step 106, the value M H of the Hth area is first compared with two set values B and C. Here, the set values B and C constitute the lower and upper limits of the medium steering angle range L (corresponding to gentle curve driving), as shown in FIGS. 4 and 5. If B≦MH≦C in step 106, the process proceeds to step 108, and
5M If 1-1≦C, 1 is added to the value D of the frequency counter (initialized to O each time the execution is executed) in step 107, and the process proceeds to step 108;
1 is subtracted from the read counter value 1 at . In the following step 109, the read counter value H becomes the numerical value O.
The above steps 106 to 106 are compared until H becomes O.
Step 108 is repeated, and when H=0, the program proceeds to the next step 1)0. Steps 106 to 108 above
By repeating this, the frequency counter value becomes the frequency of the values Mn of each storage area where B≦Mn≦C.

In the following step 1)0, the mountain road index K is calculated using the following equation.

K = D / n In this way, when driving on a city road, the frequency of the middle steering angle range I is small, so the mountain road index has a small value, and conversely, when driving on a mountain road, the frequency of the middle steering angle range I7 is small. Since the mountain road index is large, the mountain road index has a large value, and the driving condition can be determined based on the mountain road index.

Next, the process of controlling the l&damping force of the suspension according to the mountain road index K calculated as described above will be explained based on the flowchart of FIG.

First, in step 200, the mountain road index K is read, and then in step 201, the mountain road index K is multiplied by a constant A to obtain the output current value i. This output current value i is output in step 202 and applied to the solenoid 30 of the electromagnetic valve 28 by the solenoid drive circuit 61. Since the output current value i is a value corresponding to the mountain road index K, the opening area of the variable orifice 29 is controlled to be reduced by the current value applied to the solenoid 30 in proportion to the increase in the mountain road index. As a result, when driving on a mountain road, the opening area of the variable orifice 29 becomes smaller and the damping force is controlled to be larger. Conversely, when driving on a city road, the opening area of the variable orifice 2 becomes larger and the damping force is controlled to be larger. is controlled to be small.

In this way, when driving on a mountain road, the damping force of the suspension 10 is large and stiff, so even if the steering wheel 18 is frequently operated left and right, it is possible to prevent the vehicle from rolling or tilting. Steering stability during driving can be improved.

In the above embodiment, the mountain road index is calculated from the frequency ratio of a specific region of the frequency distribution of steering angles, but the mountain road index can also be calculated from the dispersion of steering angles, the frequency of stopping the car, the frequency of acceleration, etc. It is something that can be done.

Additionally, a variable orifice 29 that communicates between both chambers of the cylinder of the shock absorber 21 and a solenoid valve 28 that controls the variable orifice 29 are provided.
Of course, it is possible to incorporate the piston 25 into the piston 25 fitted into the cylinder.

<Effects of the Invention> As described above, in the present invention, a mountain road index indicating the driving condition is calculated based on the driving condition of the vehicle, and the stylus reducing force of the suspension is increased in accordance with this mountain road index when driving on a mountain path. Since the configuration is configured to control the vehicle, it is possible to prevent the vehicle from rolling or tilting when driving on a mountain road, and it has the effect of improving steering stability.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a block diagram showing the entire suspension control device, Fig. 2 is a diagram showing the frequency distribution of steering angle when driving on a mountain road, and Fig. 3 is a diagram showing the frequency distribution of steering angle when driving on a city road. FIGS. 4 and 5 are diagrams showing the frequency distribution of the steering angle in the case of , and FIGS. 4 and 5 are diagrams showing the middle of the flow. 21...Shock absorber, 2nd...Solenoid valve, 2
9...Variable orifice.

Claims (1)

[Claims] (1) The damping force of the vehicle suspension is controlled according to the mountain road index that indicates the driving condition, and an electromagnetic means for controlling the opening area of a variable orifice that changes the damping force of the suspension, and an electromagnetic means based on the driving condition. a calculation means for calculating a mountain road index according to the running condition; a calculation means for calculating an output current value according to the calculated mountain road index; and a control means for controlling the electromagnetic means based on the calculated output current value. A suspension control device comprising: