JP2001001732A - Load detection system and damping force adjusting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect payload at the periphery of a suspension where space is ample by detecting acceleration of a vehicle and vehicle height at respective wheel positions apart from each other in the acceleration direction and calculating payload on the vehicle based on the acceleration and vehicle height. SOLUTION: A vehicle is mounted with suspensions 10a to 10d at respective wheel positions of front left, front right, rear left and rear right. Respective suspensions are composed of coil springs 16a to 16d and shock absorbers 11a to 11d. Lower end portions of respective shock absorbers 11a to 11d are connected with lower arms 12a to 12d, which are also connected with wheels. Piston rods 13a to 13d are provided so as to protrude at upper end portions of the respective shock absorbers 11a to 11d. Vehicle height sensors 15a to 15d are disposed at the respective lower arms 12a to 12d and an acceleration sensor 7 for detecting acceleration in the longitudinal direction is disposed in the center of the vehicle. Signals detected by the sensors 15a to 15d and 7 are input to a control section of a load detection system 1 and payload on the vehicle is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load detecting device for determining the state of a load applied to a vehicle, such as an occupant or a load, and a control device for a vehicle that changes depending on the state of the load of the vehicle.

[0002]

2. Description of the Related Art In general, the damping force of a shock absorber provided on a suspension is made variable by an electric signal, and the damping force of the shock absorber is electronically controlled by a computer so that the change in the load on the vehicle can be prevented. Regardless of the above, there is known a damping force adjusting device configured to maintain a posture of a vehicle in an appropriate state with respect to a road surface and to optimally control damping force characteristics.

In this type of damping force adjusting device, a load detecting device is provided on each suspension in order to obtain an accurate load applied to each wheel. As the load detecting device, for example, Japanese Patent Application Laid-Open No. 4-305132 is disclosed. Some are described in. In this, the bearing part in which the upper support of the suspension is incorporated is constituted by a cylindrical inner ring into which the rod of the shock absorber is inserted, its outer ring raceway part, and a ball bearing arranged on the outer ring raceway part, A load gauge is formed by providing a strain gauge on the wall surface of the cylindrical inner ring.

[0004]

However, due to the structure of the vehicle, there is little space around the suspension, and it is difficult for the above-mentioned conventional load detecting device to be disposed on the suspension.

The present invention has been made in view of the above problems, and an object of the present invention is to make the means for detecting the loaded load of a vehicle less restricted in space.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, an acceleration detecting means for detecting an acceleration based on a change in a running state of a vehicle and an acceleration detecting means for detecting the acceleration. Vehicle height detecting means for detecting a value based on the vehicle height displacement amount of wheel positions separated from each other in the direction of acceleration,
Calculating means for calculating the load load of the vehicle from the acceleration detected by the acceleration detecting means and a value based on the amount of vehicle height displacement at wheel positions separated from each other in the direction of the acceleration detected by the vehicle height detecting means; It is characterized by having.

According to a second aspect of the present invention, the acceleration detecting means detects the longitudinal acceleration of the vehicle, and a front wheel position of the vehicle separated from the vehicle in the acceleration direction detected by the acceleration detecting means. A vehicle height detecting means for detecting a value based on the vehicle height displacement amount of the rear wheel position; a pitching state detecting means for detecting whether or not the vehicle is in a pitching state; and the pitching state detecting means determining that the vehicle is in a pitching state. In this case, the load applied to the vehicle based on the first moment at the position of the center of gravity of the vehicle about the center of pitching, the second moment at the position of the front wheels of the vehicle, and the third moment at the position of the rear wheels of the vehicle is calculated. Computing means for computing.

According to the third aspect of the present invention, the acceleration detecting means is configured to detect a longitudinal acceleration of the vehicle,
Pitching state detection means for determining whether or not the vehicle is in a pitching state, and when the pitching state detection means determines that the vehicle is in a pitching state, the calculating means determines the vehicle height direction between the center of the pitching and the center of gravity of the vehicle. The first moment determined by the deviation of the vehicle, the total weight of the vehicle, and the acceleration is a deviation in the front-rear direction of the vehicle between the pitching center and the front wheel position of the vehicle, the spring constant of the suspension provided at the front wheel position of the vehicle, and the vehicle. A second moment determined by a value based on the vehicle height displacement amount at the front wheel position, a deviation in the front-rear direction of the vehicle between the pitching center and the rear wheel position of the vehicle, and a suspension provided at the rear wheel position of the vehicle. And the third moment determined by the spring constant at the rear wheel position and the value based on the vehicle height displacement at the rear wheel position. And wherein the Rukoto.

According to a fourth aspect of the present invention, when the magnitude of the acceleration detected by the acceleration detecting means is smaller than a predetermined value, the calculation is not performed or the calculation result is invalidated.

The invention according to claim 5 is characterized in that the calculation means does not perform the calculation or invalidates the calculation result when the magnitude of the expansion / contraction change of each suspension is equal to or larger than a predetermined value.

According to a sixth aspect of the present invention, there is provided a damping force adjusting device for adjusting a damping force based on a loaded load of a vehicle by providing a shock absorber capable of adjusting a damping force between a vehicle body and a wheel.
And a damping force of the shock absorber is adjusted based on a calculation result of the load detecting device.

[0012]

(1) In the load detecting device according to the first aspect of the present invention, the acceleration generated by the change in the running state of the vehicle is detected by the acceleration detecting means. A value based on the amount of vehicle height displacement at wheel positions separated from each other in the direction of acceleration is detected by vehicle height detecting means. If the vehicle has four wheels and the change in the running state of the vehicle is pitching in which the vehicle body swings in the longitudinal direction of the vehicle, the acceleration detecting means detects the longitudinal acceleration of the vehicle, and the vehicle height detecting means Detects a value based on the vehicle height displacement at the front wheel position and the rear wheel position separated from each other in the acceleration direction. If the vehicle has four wheels and the change in the running state of the vehicle is rolling in which the vehicle body swings in the left-right direction of the vehicle, the acceleration detection means detects the lateral acceleration of the vehicle and detects the vehicle height. The detection means detects a value based on the vehicle height displacement of the right wheel and the left wheel of the vehicle separated from each other in the acceleration direction. The loaded load of the vehicle is calculated by the calculating means based on the value and the acceleration based on the vehicle height displacement amount of the wheel positions separated from each other in the direction of the acceleration. (2) In the load detecting device according to the second aspect of the present invention,
An acceleration generated in the front-rear direction of the vehicle due to a change in the running state of the vehicle is detected by an acceleration detecting unit. The vehicle height detecting means detects a value based on the vehicle height displacement at the front wheel position and the rear wheel position of the vehicle. The pitching state detecting means detects whether or not the change in the running state of the vehicle is in a pitching state. When the vehicle is in a pitching state, a first moment at a vehicle center of gravity position centered on a center position of the pitching, a second moment at a front wheel position of the vehicle, and a third moment at a rear wheel position of the vehicle are calculated. Based on this, the load detected as the load applied to the vehicle due to the occupant getting on the vehicle or carrying luggage is detected. The first to third moments are moments of inertia in pitching. (3) In the load detecting device according to the third aspect of the invention,
When the pitching state detecting means determines that the vehicle is in the pitching state, a first moment determined by the deviation in the vehicle height direction between the center of the pitching and the center of gravity of the vehicle, the gross vehicle weight, and the longitudinal acceleration of the vehicle is calculated. I do. A second moment determined by a deviation in the longitudinal direction of the vehicle between the center of pitching and the front wheel position of the vehicle, a spring constant of a suspension provided at the front wheel position of the vehicle, and a value based on a vehicle height displacement amount at the front wheel position of the vehicle. Calculate. Further, a third value is determined by a deviation in the front-rear direction of the vehicle between the center of pitching and the rear wheel position of the vehicle, a spring constant of a suspension provided at the rear wheel position of the vehicle, and a value based on a vehicle height displacement amount at the rear wheel position. Calculate the moment of. The load on the vehicle is calculated based on the fact that the first moment is balanced with the sum of the second moment and the third moment. (4) In the load detecting device according to the fourth aspect of the invention,
It is determined whether the magnitude (absolute value) of the acceleration detected by the acceleration detecting means is smaller than a predetermined value. When the acceleration is smaller than the predetermined value, the calculation error increases. In this case, the calculation is performed such that the calculation result is invalidated or the calculation is not performed. (5) In the load detecting device according to the fifth aspect of the invention,
The magnitude of the expansion / contraction change of the suspension at each wheel position is estimated. When the magnitude of the expansion / contraction change of the suspension at each wheel position is equal to or greater than a predetermined value, the calculation error increases. In this case, the calculation is performed such that the calculation result is invalidated or the calculation is not performed. (6) In the damping force adjusting device according to the sixth aspect of the present invention, the load detecting device detects the load of the vehicle and adjusts the damping force of each shock absorber to a damping force corresponding to the load of the vehicle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail.

(First Embodiment) A first embodiment will be described with reference to the drawings.

FIG. 1 shows the overall configuration of a vehicle provided with a load detecting device 1 according to one embodiment of the present invention.

The vehicle provided with the load detecting device 1 is provided with coil spring type suspensions 10a to 10d at respective wheel positions of left and right front wheels and left and right rear wheels. The suspensions 10a to 10b at the left and right front wheel positions have a spring constant of K
1 and the coil springs 16a and 16b and the shock absorber 11
a and 11b. Further, the suspensions 10a to 10b at the left and right rear wheel positions include coil springs 16c and 16d having a spring constant K2 and shock absorbers 11c and 11b.
d. The shock absorbers 11a to 11d are respectively connected at lower ends of lower arms 12a to 12d to which respective wheels are connected, and piston rods 13a to 13d whose upper ends are fixed to the vehicle body project from upper end surfaces thereof.

Each of the lower arms 12a to 12d has
A vehicle height sensor 15 which is a vehicle height detecting means for detecting the rotation of each of the lower arms 12a to 12d as a value based on the vehicle height displacement amount.
a to 15d, and an acceleration sensor 7 as acceleration detecting means for detecting the acceleration of the vehicle in the front-rear direction is provided at the center of the vehicle.

FIG. 2 is a system block diagram of the load detecting device 1.

The load detecting device 1 is provided with an ECU (Electroni
c Control Unit).
The control device 4 has a CPU 5 as a calculating means and a first memory 6 for storing a plurality of threshold values.

The control device 4 includes each lower arm 12a.
Vehicle height sensors 15a to 15d for detecting the rotation of the vehicle to 12d and an acceleration sensor 7 for detecting the acceleration of the vehicle in the longitudinal direction are connected.

FIG. 3 shows the vehicle height sensors 15a to 15d.

Each of the vehicle height sensors 15a to 15d has a case 31 rotatably supported by the vehicle body. One end of a link 33 is fixed to the case 31 via a shaft 32. The other end of the link 33 is rotatably connected to the upper end of a rod 34. The lower end of the rod 34 is rotatably connected to the lower arms 12a to 12d.

The vehicle height sensors 15a to 15d are such that when the lower arms 12a to 12d rotate, the shaft 22 and the case 31 rotate via the link 33 as shown by the arrow X. A pair of permanent magnets 35a and 35b are fixed to the inner peripheral surface of the case 31, and form a magnetic field in the direction of the arrow Y. A hall element 36 supported by the vehicle body is provided inside the case 31. The Hall element 36 outputs a predetermined voltage signal as the case 31 rotates. Based on the position of the lower arms 12a to 12d with respect to the vehicle body in a stationary state where there is no load on the vehicle, a voltage signal when the lower arms 12a to 12d are set as a reference is set as a reference signal value. Then, when the lower arms 12a to 12d rotate from the reference with the vertical displacement of the vehicle body, the voltage signal becomes a value apart from the reference signal value by a value proportional to the amount of rotation of the lower arms 12a to 12d from the reference. . Therefore, each of the vehicle height sensors 15a to 15d
Sends the voltage signal changed with the rotation of the lower arms 12a to 12d to the control device 4 as a value based on the vehicle height displacement amount at each wheel position. The control device 4 determines the vehicle height displacement amounts R1, R2 at the front wheel position from the deviation between the voltage signal changed with the rotation of the lower arms 12a to 12d and the reference position.
And the rear wheel position displacement amounts R3 and R4 of the vehicle.

The acceleration sensor 7 is configured to detect the longitudinal acceleration of the vehicle, and sends the detected acceleration G to the control device 4.

The control device 4 includes a pitching state detecting means for detecting a pitching state (a state having an inclination). The pitching state detecting means is provided with each vehicle height sensor 15.
The absolute values of the vehicle height displacement amounts R1, R2 at the front wheel position of the vehicle and the vehicle height displacement amounts R3, R4 at the rear wheel position of the vehicle calculated based on the signals a to 15d are all stored in the first memory 6. If the value is larger than the stored value P, it is determined that the vehicle is in a pitching state.

The CPU 5 has a first means for determining that a calculation error is large when the absolute value of the acceleration G is smaller than a predetermined threshold value A. The CPU 5 determines the absolute value of the expansion / contraction speed of each of the suspensions 10a to 10d to be equal to or less than a predetermined threshold B stored in the first memory 6 as one of the determinations of the magnitude of the expansion / contraction change of each of the suspensions 10a to 10d. If not, a second means for determining a transitional pitching state is provided.

The thresholds A, B, and P are values sampled in advance by experiments, and each threshold can be appropriately changed according to the required accuracy of the calculation result. If a damping force is included as a parameter for the calculation, the load can be estimated even when the vehicle is in a transient pitching state, but this is not preferable because the number of error factors increases. Therefore, in the present technology, the calculation of the moment at each wheel position does not consider the damping force, and the suspension 10a
Coil springs 16a to 16d provided for 10 to 10d
Is calculated using only the spring constants K1 and K2. Therefore, a preferable value of the expansion and contraction speed of each of the suspensions 10a to 10d is around 0, which is a case where the damping force of each of the shock absorbers 11a to 11d is small (a static state of the vehicle). Therefore, when a suitable value of the threshold value B is selected, it becomes substantially zero.

The first means determines whether or not the absolute value of the acceleration G of the detection signal from the acceleration sensor 7 is smaller than the threshold value A stored in the first memory 6. If the absolute value of the acceleration G is smaller than the threshold value A, the calculation is not performed because the calculation error is large. Alternatively, even if the calculation is performed, the estimated value is not adopted. This is to prevent the error of the estimated value from increasing when the acceleration G is too small.

The second means is that each of the vehicle height sensors 15a to 15
The expansion / contraction speed of each of the suspensions 10a to 10d is calculated by differentiating the vehicle height displacement amounts R1 to R4 calculated based on the signal d. If the absolute value of the expansion / contraction speed of each of the suspensions 10a to 10d is not equal to or smaller than the threshold value B stored in the first memory 6, it is determined that the state is a transient pitching state and the calculation is not performed. Alternatively, even if the calculation is performed, the value is not adopted.

Therefore, when the absolute value of the acceleration G detected by the acceleration sensor 7 is larger than the threshold value A and the absolute value of the expansion / contraction speed of each of the suspensions 10a to 10d is equal to or smaller than the threshold value B, the calculation is performed. It is in a pitching state where the estimated value can take a value with a small error.

FIG. 4 shows a state in which the load on the vehicle can be calculated.

The pitching center T is a value calculated based on the vehicle characteristics or a value detected by an experiment or the like and is stored in the first memory 6 in advance. Then, the load of the vehicle is calculated from the balance between the moment of inertia at the center of gravity J of the vehicle centered on the pitching center T and the sum of the moment of inertia at each wheel position.

The moment of inertia at the vehicle center of gravity J, which is the first moment, is the deviation h in the vehicle height direction between the center T of pitching and the vehicle center of gravity J, and the total vehicle weight obtained by adding the vehicle load M to the vehicle weight M. And the longitudinal acceleration G of the vehicle
From the product of

The second moment, the moment of inertia at the front wheel position of the vehicle, is determined by the deviation a in the longitudinal direction of the vehicle between the pitching center T and the front wheel position of the vehicle and the suspensions 10a and 10b provided at the front wheel position of the vehicle. A spring constant K1 of the provided coil springs 16a and 16b;
It is determined by the product of the vehicle height displacement amounts R1 and R2 at the front wheel position of the vehicle.

The third moment, that is, the moment of inertia at the rear wheel position of the vehicle is a deviation b in the longitudinal direction of the vehicle between the center T of pitching and the rear wheel position of the vehicle, and the suspension 10c provided at the rear wheel position of the vehicle. , A spring constant K2 of the coil springs 16c and 16d provided in the 10d,
It is determined by the product of the vehicle height displacement amounts R3 and R4 at the rear wheel position of the vehicle.

Here, since the first moment is in balance with the sum of the second moment and the third moment, the equation (1) is obtained.

[0037]

(Equation 1) When the load m of the vehicle is obtained from Equation 1, the equation of Equation 2 is obtained.

[0038]

(Equation 2) The spring constant K1 of the coil springs 16a, 16b provided on the suspensions 10a, 10b at the front wheel position
And the spring constants K of the coil springs 16c and 16d provided in the suspensions 10c and 10d at the rear wheel position.
2 is stored in the first memory 6.

Usually, the load m of the vehicle is periodic and does not fluctuate, so that it is possible to take an average for a certain long time. Therefore, the control device 4 performs the calculation of Equation 2 a predetermined number of times N, and obtains an average value of the calculation results of the predetermined number N of times as the load m of the vehicle.

The operation of the load detecting device 1 having the above configuration will be described with reference to the flowchart of FIG.

When the control device 4 turns on the ignition switch for activating the function of the vehicle, the control device 4 proceeds to step S
At 100, the estimated load increase W as the load m of the vehicle
And the value K of the counter that counts the number of operations and the value K of the counter
Are set to the initial value 0 with the sum value SUM of the calculation results of the number of times indicated by. Next, in step S110, the absolute values of the vehicle height displacement amounts R1 and R2 at the front wheel position of the vehicle and the vehicle height displacement amounts R3 and R4 at the rear wheel position of the vehicle calculated based on the signals of the vehicle height sensors 15a to 15d. If all of the values are larger than the threshold value P stored in the first memory 6, it is determined that the vehicle is in the pitching state, and the process proceeds to step S120. In addition, at least one of the absolute values of the vehicle height displacement amounts R1 and R2 at the front wheel position of the vehicle and the vehicle height displacement amounts R3 and R4 at the rear wheel position of the vehicle calculated based on the signals of the vehicle height sensors 15a to 15d is calculated. When it is smaller than the threshold value P stored in the first memory 6, it is determined that the vehicle is not in the pitching state, and the process proceeds to step S190. In step S120, it is determined whether or not the absolute value of the acceleration detected by the acceleration sensor 7 is equal to or larger than the threshold value A in order to cut the range of the acceleration in which the calculation error increases. If the absolute value of the acceleration is equal to or greater than the threshold value A, the process proceeds to step S130, and if it is equal to or less than the threshold value A, the process proceeds to step S190. In step S130, the expansion / contraction speed of the suspensions 10a to 10d is
Vehicle height displacement amount R calculated based on signals of 5a to 15d
The calculation is performed by differentiating 1 to R4. Whether or not all the absolute values of the expansion / contraction speeds are equal to or less than the threshold value B is determined as to whether or not a transitional pitching state is present. If the absolute value of the expansion / contraction speed is not less than the threshold B

It is determined that there is a transitional pitching state in which there is a large error in the calculation result of Equation 2, and the flow advances to Step S190. If all the absolute values of the expansion / contraction speed are equal to or smaller than the threshold value B, the acceleration G in the longitudinal direction of the vehicle is determined in step S140.
Based on the vehicle height displacement amounts R1 to R4 at the respective wheel positions, the load m of the vehicle is calculated using Equation 2, and is added to the sum SUM of the calculation results.
Add 1 to 0. Next, at step S160, a predetermined number of times N
It is determined whether or not the value K of the counter is a predetermined number N in order to determine whether or not the calculation is being performed. If the value K of the counter is the predetermined number N, the process proceeds to step S170 and the value SUM of the sum of the calculation results An average value of the results of the predetermined number N of operations is obtained, and the average value is used as the estimated load increase value W. Step S1
At 80, the sum value SUM of the operation result and the counter value are changed to the initial value 0. In step S190, it is determined whether or not the estimated load increase value W is equal to or greater than a predetermined threshold value C stored in the first memory. The estimated load increase W is equal to a predetermined threshold C
In the following cases, it is determined that the calculation result has a large error, the process proceeds to step S210, the load increase estimated value W is changed to the initial value 0, and the process returns to step S110 to continue the calculation. However, when the estimated load increase W is equal to or greater than the predetermined threshold value C, the estimated load increase W is output as the load m of the vehicle in step S200, and the estimated load increase W is set to the initial value 0 in step S210. And returns to step S110.

According to this embodiment, each of the lower arms 12a-1
Based on the output results from the respective vehicle height sensors 15a to 15d connected to 2d and the acceleration sensor 7 for detecting the longitudinal acceleration of the vehicle, it is possible to easily calculate the load m of the vehicle by using Equation 2. it can. Therefore, without disposing a sensor or the like in a small space around the suspension, a vehicle height sensor disposed between the lower arm and the vehicle body or an acceleration sensor disposed at an arbitrary position on the vehicle body reduces the load of the vehicle. Can be detected. Further, the calculation accuracy of the present technology can calculate an accurate vehicle load by cutting a condition having a large error by a plurality of threshold values. Furthermore, by averaging calculation results of a predetermined number of times (predetermined time), it is possible to improve calculation accuracy.

(Second Embodiment) A second embodiment will be described with reference to the drawings.

FIG. 6 shows the overall structure of a vehicle provided with a load detecting device 2 according to one embodiment of the present invention. FIG. 2 shows a system block diagram of the load detection device 2. The same components as those in the first embodiment are denoted by the same reference numerals, and only the portions different from the above-described embodiment will be described.

The load detecting device 2 is different from the load detecting device 1 of the first embodiment shown in FIG. 1 in that the coil spring type suspensions 10a to 10d provided at the respective wheel positions are replaced by air spring type suspensions 20a to 20d. It is what it was. Suspension 20a at the left and right front wheel positions,
20b indicates that the spring constant when the loaded load of the vehicle is 0 is K3
Air springs 26a, 26b and shock absorbers 21a, 21
b. Left and right front wheel position suspension 2
0c and 20d are the air springs 26c and 26d having the spring constant K4 when the load of the vehicle is 0 and the shock absorber 21.
c, 21d. The configuration except for this point is the same.

However, as a characteristic of the air springs 26a to 26d constituting the suspensions 20a to 20d, the spring constant changes in proportion to the load applied to the suspensions 20a to 20d. Assuming that the load m of the vehicle is equally applied to each of the suspensions 20a to 20d, the air spring 2 forming each of the suspensions 20a to 20d
The spring constants of 6a to 26d increase at a constant rate. However, assuming a general vehicle, most of the load increase factors such as occupants, luggage, and fuel are concentrated on the rear side of the vehicle.
Therefore, in the present embodiment, it is considered that all the load m of the vehicle is applied to the suspensions 20c and 20d at the rear wheel position, and the spring constant in this case is K5.

The control device 4 includes a pitching state detecting means for detecting a pitching state (a state having an inclination). The pitching state detecting means is provided with each vehicle height sensor 15.
vehicle height displacement amount R at the front wheel position of the vehicle detected in a to 15d
When all of the absolute values of R1, R2 and the vehicle height displacement amounts R3, R4 at the rear wheel position of the vehicle are larger than the value P stored in the first memory 6, it is determined that the vehicle is in the pitching state.

The CPU 5 has a first means for judging that a calculation error is large when the absolute value of the acceleration G is smaller than a predetermined threshold value A. The CPU 5 determines the absolute value of the expansion / contraction speed of each of the suspensions 20a to 20d to be equal to or less than a predetermined threshold B stored in the first memory 6 as one of the methods for determining the magnitude of the expansion / contraction change of each of the suspensions 20a to 20d. If not, a second means for determining a transitional pitching state is provided.

The thresholds A, B, and P are values sampled in advance by experiments, and each threshold can be appropriately changed according to the required accuracy of the calculation result. If a damping force is included as a parameter for the calculation, the load can be estimated even when the vehicle is in a transient pitching state, but this is not preferable because the number of error factors increases. Therefore, in the present technology, the calculation of the moment at each wheel position does not consider the damping force, and each suspension 20a
The calculation is performed using only the spring constants K3 and K5 of the air springs 26a to 26d provided for the air springs 26 to 26d. Therefore, a preferable value of the expansion and contraction speed of each of the suspensions 20a to 20d is around 0, which is a case where the damping force of each of the shock absorbers 20a to 20d is small (static state of the vehicle). Therefore, when a suitable value of the threshold value B is selected, it becomes substantially zero.

The first means determines whether or not the absolute value of the acceleration G of the detection signal from the acceleration sensor 7 is smaller than the threshold value A stored in the first memory 6. If the absolute value of the acceleration G is smaller than the threshold value A, the calculation is not performed because the calculation error is large. Alternatively, even if the calculation is performed, the estimated value is not adopted. This is to prevent the error of the estimated value from increasing when the acceleration G is too small.

The second means is that each of the vehicle height sensors 15a to 15
The vehicle height displacement amounts R1 to R4 calculated based on the signal d are differentiated to calculate the expansion / contraction speed of each of the suspensions 20a to 20d. If the absolute value of the expansion / contraction speed of each of the suspensions 20a to 20d is not less than or equal to the threshold value B stored in the first memory 6, it is determined that a transient pitching state has occurred, and no calculation is performed. Alternatively, even if the calculation is performed, the value is not adopted.

Therefore, when the absolute value of the acceleration G detected by the acceleration sensor 7 is larger than the threshold value A and the absolute value of the expansion / contraction speed of each of the suspensions 20a to 20d is equal to or smaller than the threshold value B, the calculation is performed. It is in a pitching state where the estimated value can take a value with a small error.

FIG. 7 shows a state in which the load on the vehicle can be calculated.

The pitching center T is a value calculated based on the vehicle characteristics or a value detected by an experiment or the like, which is stored in the first memory 6 in advance. Then, the load m of the vehicle is calculated from the balance between the moment of inertia at the vehicle center of gravity J centered on the pitching center T and the sum of the moment of inertia at each wheel position.

The moment of inertia at the center of gravity J of the vehicle, which is the first moment, is the deviation h in the vehicle height direction between the center T of pitching and the center of gravity J of the vehicle, and the total vehicle weight obtained by adding the vehicle load M to the vehicle weight M. And the longitudinal acceleration G of the vehicle
From the product of

The moment of inertia at the front wheel position of the vehicle, which is the second moment, is determined by the deviation a in the longitudinal direction of the vehicle between the pitching center T and the front wheel position of the vehicle and the suspensions 20a and 20b provided at the front wheel position of the vehicle. It is determined by the product of the spring constant K3 of the provided air springs 26a and 26b and the vehicle height displacement amounts R1 and R2 at the front wheel position of the vehicle.

The moment of inertia at the rear wheel position of the vehicle, which is the third moment, is determined by a deviation b in the front-rear direction of the vehicle between the pitching center T and the rear wheel position of the vehicle, and a suspension 20c provided at the rear wheel position of the vehicle. , 20d, and the spring constants K5 of the air springs 26c, 26d provided in the vehicle and the vehicle height displacement amounts R3, R4 at the rear wheel position of the vehicle.

Here, since the first moment is balanced with the sum of the second moment and the third moment,
Is obtained.

[0060]

(Equation 3) When the load m of the vehicle is obtained from Equation 3, the equation of Equation 4 is obtained.

[0061]

(Equation 4) In this embodiment, it is assumed that the load m of the vehicle is applied to the suspensions 20a to 20d at the rear wheel positions.
Therefore, the air springs 26a to 26d at each wheel position
Is as follows.

The suspension 20a at the front wheel position,
As the spring constant K3 of 20b, a value stored in the first memory 6 when the load m of the vehicle is 0 is used.

The air spring 26c at the rear wheel position
Since the spring constant K5 of 26d changes in proportion to the load applied to the suspensions 20c and 20d as described above, the loaded load of the vehicle stored in the first memory 6 is zero.
Is calculated based on the spring constant K4 of the air springs 26c and 26d in the state of. Therefore, the spring constant K5 of the air springs 26c and 26d at the rear wheel position is determined by the ratio of the total vehicle weight obtained by adding the vehicle load m to the vehicle weight to the vehicle weight, and the air springs 26c and 26d when the vehicle is not loaded. Is obtained by multiplying the spring constant K4 by

[0064]

(Equation 5) Therefore, by substituting Equation 5 into Equation 4, Equation 6 can be obtained.

[0065]

(Equation 6) Further, when Equation 6 is obtained for the load m of the vehicle, Equation 7 can be obtained.

[0066]

(Equation 7) Usually, the load m of the vehicle is periodic and does not fluctuate.
It is possible to take an average of some long time. Therefore, the control device 4 performs a predetermined number N of calculations based on Expression 7, and obtains an average value of the predetermined number N of calculation results as the load m of the vehicle.

The operation of the load detecting device 1 having the above configuration will be described with reference to the flowchart of FIG.

When the control device 4 turns on the ignition switch for activating the function of the vehicle, step S
At 101, the estimated load increase W as the load m of the vehicle
And the value K of the counter that counts the number of operations and the value K of the counter
Are set to the initial value 0 with the sum value SUM of the calculation results of the number of times indicated by. Next, in step S111, the absolute values of the vehicle height displacement amounts R1, R2 at the front wheel position of the vehicle and the vehicle height displacement amounts R3, R4 at the rear wheel position of the vehicle calculated based on the signals of the vehicle height sensors 15a to 15d. If all of the values are larger than the threshold value P stored in the first memory 6, it is determined that the vehicle is in the pitching state, and the process proceeds to step S121. In addition, at least one of the absolute values of the vehicle height displacement amounts R1 and R2 at the front wheel position of the vehicle and the vehicle height displacement amounts R3 and R4 at the rear wheel position of the vehicle calculated based on the signals of the vehicle height sensors 15a to 15d is calculated. When it is smaller than the threshold value P stored in the first memory 6, it is determined that the vehicle is not in the pitching state, and the process proceeds to step S191. In step S121, it is determined whether or not the absolute value of the acceleration detected by the acceleration sensor 7 is equal to or larger than the threshold value A in order to cut the range of the acceleration in which the calculation error increases. If the absolute value of the acceleration is equal to or larger than the threshold A, the process proceeds to step S131. If the absolute value is equal to or smaller than the threshold A, the process proceeds to step S191. In step S131, the expansion / contraction speed of the suspensions 21a to 21d is
Vehicle height displacement amount R calculated based on signals of 5a to 15d
The calculation is performed by differentiating 1 to R4. Whether or not all the absolute values of the expansion / contraction speeds are equal to or less than the threshold value B is determined as to whether or not a transitional pitching state is present. If the absolute value of the expansion / contraction speed is not less than the threshold B

It is determined that the transitional pitching state has a large error in the calculation result of Expression 7, and the flow advances to step S191. If all of the absolute values of the expansion / contraction speed are equal to or smaller than the threshold value B, the acceleration G in the front-rear direction of the vehicle is determined in step S141.
Based on the vehicle height displacement amounts R1 to R4 at the respective wheel positions, the load load m of the vehicle is calculated using Equation 7, and the calculated load m is added to the sum SUM of the calculation results.
One is added by one. Next, at step S161, a predetermined number of times N
It is determined whether or not the value K of the counter is a predetermined number N in order to determine whether or not the calculation is being performed. If the value K of the counter is the predetermined number N, the process proceeds to step S171 to calculate the sum SUM of the calculation results. An average value of the results of the predetermined number N of operations is obtained, and the average value is used as the estimated load increase value W. Step S1
In step 81, the value SUM of the sum of the operation results and the value of the counter are changed to the initial value 0. In step S191, it is determined whether or not the estimated load increase value W is equal to or greater than a predetermined threshold value C stored in the first memory. The estimated load increase W is equal to a predetermined threshold C
In the following cases, it is determined that the calculation result has a large error, the process proceeds to step S211 and the estimated load increase value W is changed to the initial value 0, and the process returns to step S111 to continue the calculation. However, when the estimated load increase W is equal to or greater than the predetermined threshold value C, the estimated load increase W is output as the load m of the vehicle in step S201, and the estimated load increase W is initialized to 0 in step S211. And returns to step S111.

Therefore, according to the present embodiment, each of the vehicle height sensors 15a to 15d connected to each of the lower arms 12a to 12d.
Based on the output results from 5d and the acceleration sensor 7 for detecting the acceleration of the vehicle in the front-rear direction, the load m of the vehicle can be easily calculated using Expression 7. Therefore, without disposing a sensor or the like in a small space around the suspension, a vehicle height sensor disposed between the lower arm and the vehicle body or an acceleration sensor disposed at an arbitrary position on the vehicle body reduces the load of the vehicle. Can be detected. In addition, the calculation accuracy of the present technology is such that by cutting a condition having a large error by a plurality of threshold values, it is possible to calculate an accurate vehicle loading load. (Third Embodiment) The form will be described with reference to the drawings.

FIG. 1 shows the overall configuration of a vehicle provided with a damping force adjusting device 31 having the load detecting device 1 according to the first embodiment of the present invention.
The same components as those in the first embodiment are denoted by the same reference numerals.

The vehicle provided with the damping force adjusting device 31
Coil spring type suspensions 10a to 10d are provided at the respective wheel positions of the left and right front wheels and the left and right rear wheels. The suspensions 10a to 10b at the left and right front wheel positions include coil springs 16a and 16b having a spring constant of K1 and shock absorbers 11a and 11b. Further, the suspensions 10a to 10b at the left and right rear wheel positions have coil springs 16c and 16d having a spring constant of K2 and a shock absorber 11c,
11d. The shock absorbers 11a to 11d
Are connected at the lower ends of the lower arms 12a to 12d to which the respective wheels are connected, and piston rods 13a to 13d whose upper ends are fixed to the vehicle body protrude from the upper ends thereof. The piston rod 13a of the shock absorbers 11a to 11d
Actuators 14a to 14d as damping force adjusting means for adjusting the damping force by a signal from the damping force adjusting device 31 of the shock absorbers 11a to 11d are disposed at the upper end portions of the dampers 11a to 11d.

Each of the lower arms 12a to 12d has
Vehicle height sensors 15a to 15d similar to those of the first embodiment are provided as vehicle height detecting means for detecting the rotation of each of the lower arms 12a to 12d as a value based on the vehicle height displacement. At the center of the vehicle, an acceleration sensor 7 is provided as acceleration detecting means for detecting the longitudinal acceleration of the vehicle.

FIG. 9 is a system block diagram showing a damping force adjusting device.

The damping force adjusting device 31 includes the load detecting device 1 for obtaining the load m of the vehicle and the control unit 9. The control unit 9 includes a second memory 8 for storing a plurality of damping forces corresponding to the load m of the vehicle.

The control unit 9 receives a signal indicating the load m of the vehicle from the load detection device 1 in the first embodiment. Further, based on this signal, the vehicle load m
Is increased or decreased, and a damping force corresponding to the load m of the vehicle is selected from a plurality of damping forces stored in the second memory 8, and the actuators disposed at the respective wheel positions are selected. It is configured to transmit a signal for adjusting the damping force to 14a to 14d. The damping force corresponding to the load m of the vehicle has a value such that the damping force of each of the shock absorbers 11a to 11d becomes harder as the load m of the vehicle increases. Further, the value is such that the damping force of each of the shock absorbers 11a to 11d becomes softer when the load m of the vehicle is reduced.

The actuators 14a to 14d are
It is configured to adjust the damping force of each of the shock absorbers 11a to 11d based on a signal from the control unit 9.

Next, the operation of the damping force adjusting device 31 having the above configuration will be described.

The control unit 9 receives a signal indicating the loaded load m of the vehicle from the load detecting device 1. Next, a damping force corresponding to a signal from the load detecting device is selected from the plurality of damping forces stored in the second memory. Further, the selected damping force is transmitted as a signal to the actuators 14a to 14d. Actuators 14a to 14d receiving this signal
Adjusts the damping force of the shock absorbers 11a to 11d to the damping force indicated by the signal.

Therefore, in the damping force adjusting device 31 according to the present embodiment, the load detecting device 1 according to the first embodiment is used for detecting the loaded load of the vehicle, and only the actuators 14a to 14d are provided on the suspensions 10a to 10d. As a result, the configuration of the suspensions 10a to 10d can be simplified.

(Fourth Embodiment) A fourth embodiment will be described with reference to the drawings.

FIG. 6 shows an overall configuration of a vehicle including a damping force adjusting device 32 having the load detecting device 2 according to the second embodiment of the present invention.
The same components as those in the second embodiment are denoted by the same reference numerals. The same components as those in the second embodiment are denoted by the same reference numerals.

The vehicle provided with the damping force adjusting device 32
Air spring type suspensions 20a to 20d capable of changing the damping force are provided at the left and right front wheels and the left and right rear wheels. Suspensions 20a at the left and right front wheel positions, 2
0b indicates the air springs 26a and 26b having the spring constant K3 and the shock absorbers 21a and 21b when the load of the vehicle is 0.
It is composed of Left and right front wheel position suspension 20
c and 20d are the air springs 26c and 26d having the spring constant K4 when the load of the vehicle is 0 and the shock absorber 21c,
21d. The shock absorbers 21a to 21d
Are connected to the lower arms 12a to 12d to which the respective wheels are connected, and piston rods 13a to 13d whose upper ends are fixed to the vehicle body project from the upper end surfaces thereof. The piston rods 13a to 13d of the shock absorbers 21a to 21d
Actuators 14a to 14d as damping force adjusting means for adjusting the damping force by a signal from the damping force adjusting device 32 of the shock absorbers 21a to 21d are arranged at the upper end of the damper 21a to 21d.

Each of the lower arms 12a to 12d has
Vehicle height sensors 15a to 15d are provided as vehicle height detecting means for detecting the rotation of each of the lower arms 12a to 12d as a value based on the vehicle height displacement amount, and are provided at the center of the vehicle. Is provided with an acceleration sensor 7 as acceleration detecting means for detecting the acceleration in the front-rear direction of the vehicle.

FIG. 9 is a system block diagram showing the damping force adjusting device 32.

The damping force adjusting device 32 includes a load detecting device 2 for obtaining the load m of the vehicle and a control unit 9. The control unit 9 includes a second memory 8 for storing a plurality of damping forces corresponding to the load m of the vehicle. The control unit 9 receives a signal indicating the load m of the vehicle from the load detection device 2 according to the second embodiment. Furthermore,
Based on this signal, a damping force corresponding to the load m of the vehicle is selected from a plurality of damping forces stored in the second memory 8, and the actuators 14a disposed at the respective wheel positions are selected.
To 14d, a signal for adjusting the damping force of each of the shock absorbers 21a to 21d is transmitted. The damping force corresponding to the load m of the vehicle has a value such that the damping force of each of the shock absorbers 21a to 21d becomes harder as the load m of the vehicle increases. Further, the value is such that the damping force of each of the shock absorbers 21a to 21d becomes softer when the load m of the vehicle decreases.

The actuators 14a to 14d are
It is configured to adjust the damping force of each of the buffers 21a to 21d based on a signal from the control unit 9.

Next, the operation of the damping force adjusting device 32 having the above configuration will be described.

Control unit 9 receives a signal indicating load m of the vehicle from load detection device 2. Next, a damping force corresponding to the signal received from the load detecting device 2 is selected from a plurality of damping forces stored in the second memory 8. Further, the selected damping force is transmitted as a signal to the actuators 14a to 14d. Actuator 14a receiving this signal
14d adjusts the damping force of the shock absorbers 21a to 21d to the damping force indicated by the signal.

Therefore, in the damping force adjusting device 32 according to the present embodiment, the load detecting device 2 according to the second embodiment is used for detecting the loaded load of the vehicle, and only the actuators 14a to 14d are provided on the suspensions 20a to 20d. As a result, the configuration of the suspensions 20a to 20d can be simplified.

(Fifth Embodiment) In the above-described first and second embodiments of the present invention, an example of the pitching state detection means has been described. Another example of the means will be described.

The pitching state detecting means determines that the vehicle is in a pitching state if the acceleration detected by the acceleration sensor is equal to or greater than a predetermined threshold value. The threshold value is stored in a memory in the control device, and is a value sampled in advance by an experiment or the like.

When the detected acceleration is equal to or greater than the predetermined threshold value, each suspension has expanded and contracted, and the vehicle height at each wheel position has changed by a predetermined amount. Therefore, it is possible to determine that the vehicle is in the pitching state.

(Sixth Embodiment) In the above-described first and second embodiments of the present invention, an example of the second means for judging the transitional pitching state has been described. In the embodiment, another example of the second means will be described.

The second means uses a CPU to calculate the rate of change of the acceleration detected by the acceleration sensor. The second means is
If the calculated absolute value of the change rate of the acceleration is not less than a predetermined threshold value, it is determined that the vehicle is in a transient pitching state.

There is a fixed relationship between the acceleration and the expansion / contraction change of each suspension. When the acceleration changes, the force applied to each suspension changes. This causes each suspension to expand and contract. Therefore, when the absolute value of the rate of change of the acceleration is equal to or less than the predetermined threshold,
The change in the force applied to each suspension is small, and the change in expansion and contraction of each suspension is less than a predetermined value. In this case, it can be determined that the vehicle is not in a transitional pitching state, the calculation is possible, and the calculation result is valid.

As the threshold value, a value sampled in advance by an experiment or the like is stored in a memory in the control device.

[0098] The present invention is not limited to the above-described embodiment, but can be carried out as follows, with appropriate modifications without departing from the spirit of the invention. (1) In the above embodiment, the case where the running state of the vehicle is the pitching state has been described. However, the above formula is changed according to a change in the running state of the vehicle such as a roll to calculate the load capacity of the vehicle. It is possible. In this case, a lateral acceleration is used instead of the longitudinal acceleration. Also,
The calculation is performed using the moment in the left and right direction at the center of gravity of the vehicle instead of the moment in the vehicle longitudinal direction at the center of gravity of the vehicle. (2) In the above embodiment, the value based on the displacement of the vehicle height is measured by the vehicle height sensor provided on the lower arm. However, an acceleration sensor that detects the acceleration in the vertical direction of the vehicle may be used. Also, the displacement of the vehicle height was directly detected by the vehicle height sensor,
The vehicle height which can detect the displacement of the vehicle height by calculation may be detected. (3) In the above-described embodiment, the load of the vehicle is calculated by averaging the calculation results of the predetermined number of formulas 2 or 7; The calculation results may be averaged. (4) In the above embodiment, the load detection device is used for adjusting the damping force of the suspension, but may be used for controlling the ABS and the anti-spin device and changing the map or control parameters for engine output control and the like. (5) In the above-described embodiment, the damping force adjusting device adjusts the damping force of the shock absorber based on the calculation result of the load detecting device. In addition to this, the damping force adjusting device is accompanied by a conventional roll, pitching, inertia force, and the like. You may combine the damping force adjustment apparatus which performs.

[0099]

According to the load detecting device of the present invention, without providing the load detecting device on the suspension, the load generated by the change in the running state of the vehicle and the value based on the vehicle height displacement at each wheel position can be easily obtained. Since the loaded load of the vehicle can be calculated, the load can be estimated in a form in which there is little space restriction.

Further, by judging the running state of the vehicle having a large calculation error, it is possible to calculate an accurate vehicle load.

Further, in the damping force adjusting device provided with the load detecting device, the damping force of the suspension can be adjusted according to the load of the vehicle.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle including a device according to a first embodiment and a third embodiment.

FIG. 2 is a system configuration diagram of a load detection device.

FIG. 3 is a perspective view of a vehicle height sensor provided in the device according to the first to fourth embodiments.

FIG. 4 is a schematic diagram showing a pitching state of a vehicle including a coil spring type suspension.

FIG. 5 is a flowchart illustrating an operation of the load detection device according to the first embodiment.

FIG. 6 is an overall configuration diagram of a vehicle including the devices according to the second and fourth embodiments.

FIG. 7 is a schematic diagram showing a pitching state of a vehicle including an air spring type suspension.

FIG. 8 is a flowchart illustrating an operation of the load detection device according to the second embodiment.

FIG. 9 is a system configuration diagram of a damping force adjusting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Load detection apparatus concerning 1st Embodiment 2 ... Load detection apparatus concerning 2nd Embodiment 31 ... Damping force adjustment apparatus concerning 3rd Embodiment 32 ... Damping force adjusting device according to the fourth embodiment 4 ... Control device 5 ... CPU 6 ... First memory 7 ... Acceleration sensor 8 ... Second memory 9 ... Control Part 10a to 10d: Coil spring type suspension 11a to 11d: Cushion 16a to 16d: Coil spring 20a to 20d: Air spring type suspension 21a to 21d: Cushion 26a to 26d ... air springs 12a to 12d ... lower arms 13a to 13d ... piston rods 14a to 14d ... actuators 15a to 15d ... vehicle height sensors 31 ... Case 32 ... Shaft 33 ... Link 34 ... Rod 35a, 35b ... Permanent magnet 36 ... Hall element m ... Vehicle loading load G ... Acceleration M ... Vehicle weight W ... Estimated load increase value K ... Counter value indicating the number of calculations SUM ... Sum value of the calculation result of the number of times indicated by the counter value N ... Predetermined number of calculations T ... Center of pitching J: Position of the center of gravity a: Deviation in the longitudinal direction of the vehicle from the center of pitching to the front wheel position b: Deviation in the longitudinal direction of the vehicle from the center of pitching to the rear wheel position h: Pitching Vertical deviation of the vehicle from the center to the position of the center of gravity K1 ... Spring constant of coil spring in left and right front wheels K2 ... Spring constant of coil spring in left and right rear wheels K3 ... Airs in left and right front wheels The spring constant of the air spring in the left and right rear wheels in the case of the spring constant K4 · · · movable load of the vehicle of the ring are joined by live load of the air spring the spring constant K5 · · · vehicle at left and right rear wheels in the case of 0

Claims (6)

[Claims] An acceleration detecting means for detecting an acceleration based on a change in a running state of a vehicle, and a vehicle for detecting a value based on a vehicle height displacement of wheel positions separated from each other in a direction of the acceleration detected by the acceleration detecting means. A load load of the vehicle is calculated from a height detection unit, an acceleration detected by the acceleration detection unit, and a value based on a vehicle height displacement amount of wheel positions separated from each other in a direction of the acceleration detected by the vehicle height detection unit. Arithmetic means;
A load detecting device comprising: 2. The vehicle according to claim 1, wherein said acceleration detecting means is configured to detect an acceleration of the vehicle in the front-rear direction, and a front wheel position and a rear wheel position of the vehicle separated from each other in the acceleration direction detected by said acceleration detecting means. Vehicle height detecting means for detecting a value based on the vehicle height displacement amount; pitching state detecting means for detecting whether or not the vehicle is in a pitching state; and pitching when the pitching state detecting means determines that the vehicle is in a pitching state. Calculating means for calculating the load of the vehicle based on the first moment at the vehicle center of gravity position about the center of the vehicle, the second moment at the vehicle front wheel position, and the third moment at the vehicle rear wheel position. The load detecting device according to claim 1, comprising: 3. The vehicle according to claim 1, wherein said acceleration detecting means is configured to detect an acceleration in a longitudinal direction of the vehicle, and includes a pitching state detecting means for judging whether or not the vehicle is in a pitching state. When it is determined that the vehicle is in a pitching state, the calculating means calculates a first moment determined by a deviation in the vehicle height direction between the center of the pitching and the center of gravity of the vehicle, the total weight of the vehicle, and the acceleration. A second moment determined by a deviation in the front-rear direction of the vehicle from the front wheel position, a spring constant of a suspension provided at the front wheel position of the vehicle, and a value based on the vehicle height displacement at the front wheel position of the vehicle; In the front-rear direction of the vehicle with respect to the rear wheel position of the vehicle, the spring constant of a suspension provided at the rear wheel position of the vehicle, and the vehicle height displacement amount at the rear wheel position Load detecting device according to claim 1 and claim 2, characterized in that for computing the carrying weight of the vehicle since the balance with the sum of the third moment determined by the basis values. 4. The load detecting device according to claim 1, wherein said calculating means does not perform the calculation or invalidates the calculation result when the magnitude of the acceleration is smaller than a predetermined value. 5. The apparatus according to claim 1, wherein said operation means does not execute the operation or invalidates the operation result when the magnitude of the change in expansion and contraction of each suspension is equal to or more than a predetermined value. Load detection device. 6. A damping force adjusting device comprising a shock absorber capable of adjusting a damping force between a vehicle body and a wheel, wherein the damping force is adjusted based on a loaded load of the vehicle. A damping force adjusting device comprising the load detecting device and adjusting a damping force of the shock absorber based on a calculation result of the load detecting device.