Vehicle Driving Control System

Abstract

To provide a technique that is able to obtain a quantity of state of a gravity-center-position with higher accuracy by three accelerator sensors disposed in a vehicle.SOLUTION: A first accelerator sensor 2a is disposed at a position closer to one of wheels than a center-of-gravity position g1. A second accelerator sensor 2b is disposed in a region different from a region in which the first accelerator sensor 2a is disposed, of two regions partitioned by a virtual line 6 passing through the center-of-gravity position in a vehicle longitudinal direction. A third accelerator sensor 2c is disposed in a region different from the region in which the first accelerator sensor 2a is disposed, of two regions partitioned by a virtual line 8 passing through the center-of-gravity position in a vehicle lateral direction. At least one of a first condition that the third accelerator sensor 2c is located between the first accelerator sensor 2a and the second accelerator sensor 2b in the vehicle lateral direction and a second condition that the second accelerator sensor 2b is located between the first accelerator sensor 2a and the third accelerator sensor 2c in the vehicle longitudinal direction is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle cruise control system. [Background technology]

[0002] Patent Document 1 discloses a technique in which vertical acceleration sensors are placed at three locations corresponding to the right front wheel, the left rear wheel, and the right rear wheel, and the bounce acceleration, pitching angular acceleration, and roll angular acceleration at the center of gravity of the vehicle are calculated based on the detection values ​​of these sensors.The hydraulic cylinder of the suspension is controlled based on the calculated bounce acceleration, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-006882 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, for example, the detection value of the vertical acceleration sensor corresponding to the right front wheel is not used to calculate the roll angular acceleration at the center of gravity, so the accuracy of the roll angular acceleration at the center of gravity may be low.

[0005] An object of the present invention is to provide a technique that can obtain state quantities of the center of gravity position with higher accuracy by using three acceleration sensors arranged on a vehicle. [Means for solving the problem]

[0006] In order to solve the above problems, a vehicle cruise control system according to an embodiment of the present invention includes a first acceleration sensor that detects vertical acceleration and is disposed closer to one wheel than a center of gravity of a sprung structure of a vehicle, a second acceleration sensor that detects vertical acceleration and is disposed in a region other than the region where the first acceleration sensor is disposed among two regions divided by a virtual line passing through the center of gravity in a vehicle longitudinal direction, and a third acceleration sensor that detects vertical acceleration and is disposed in a region other than the region where the first acceleration sensor is disposed among two regions divided by a virtual line passing through the center of gravity in a vehicle width direction, and a control device that derives heave acceleration, roll angular acceleration, and pitch angular acceleration of the center of gravity based on the vertical accelerations detected by the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor, respectively. At least one of a first condition that the third acceleration sensor is located between the first acceleration sensor and the second acceleration sensor in the vehicle width direction and a second condition that the second acceleration sensor is located between the first acceleration sensor and the third acceleration sensor in the vehicle longitudinal direction is satisfied. The first condition includes that the third acceleration sensor is located near a middle position between the first acceleration sensor and the second acceleration sensor in a vehicle width direction, and the second condition includes that the second acceleration sensor is located near a middle position between the first acceleration sensor and the third acceleration sensor in a vehicle front-rear direction. s1 The vertical acceleration detected by the second acceleration sensor is z s2 The vertical acceleration detected by the third acceleration sensor is z s3 p1, p2, and p3 are coefficients, and the control device is s1 +p2·z s2 +p3·z s3 is derived as the pitch angular acceleration. p1 is determined according to the position of the third acceleration sensor in the vehicle width direction. The value of p1 when it is assumed that the third acceleration sensor is located at an intermediate position between the first acceleration sensor and the second acceleration sensor in the vehicle width direction is set as a reference value, and the position of the third acceleration sensor in the vehicle width direction is determined so that p1 falls within a range of ±33% of the reference value when the first condition is satisfied. A vehicle cruise control system according to another embodiment of the present invention includes a first acceleration sensor for detecting vertical acceleration, which is disposed closer to one wheel than a center of gravity of a sprung structure of a vehicle, a second acceleration sensor for detecting vertical acceleration, which is disposed in a region other than the region where the first acceleration sensor is disposed among two regions separated by a virtual line passing through the center of gravity in a vehicle longitudinal direction, and a third acceleration sensor for detecting vertical acceleration, which is disposed in a region other than the region where the first acceleration sensor is disposed among two regions separated by a virtual line passing through the center of gravity in a vehicle width direction, and a control device for deriving a heave acceleration, a roll angular acceleration, and a pitch angular acceleration of the center of gravity based on the vertical accelerations detected by the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor, respectively. At least one of a first condition that the third acceleration sensor is located between the first acceleration sensor and the second acceleration sensor in the vehicle width direction and a second condition that the second acceleration sensor is located between the first acceleration sensor and the third acceleration sensor in the vehicle longitudinal direction is satisfied. The first condition includes that the third acceleration sensor is located near a middle position between the first acceleration sensor and the second acceleration sensor in a vehicle width direction, and the second condition includes that the second acceleration sensor is located near a middle position between the first acceleration sensor and the third acceleration sensor in a vehicle front-rear direction. s1 The vertical acceleration detected by the second acceleration sensor is z s2 The vertical acceleration detected by the third acceleration sensor is z s3 where r1, r2, and r3 are coefficients, and the control device is s1 +r2·z s2 +r3·z s3 is derived as the roll angular acceleration. r1 is determined according to the position of the second acceleration sensor in the vehicle longitudinal direction. The value of r1 when it is assumed that the second acceleration sensor is located at an intermediate position between the first acceleration sensor and the third acceleration sensor in the vehicle longitudinal direction is set as a reference value, and the position of the second acceleration sensor in the vehicle longitudinal direction is determined so that r1 falls within a range of ±33% of the reference value when the second condition is satisfied. Effect of the Invention

[0007] According to the present invention, the state quantity of the center of gravity position can be obtained with higher accuracy by using three acceleration sensors arranged on the vehicle. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of a vehicle driving control system according to an embodiment; [Diagram 2] FIG. 2 is a diagram illustrating a first arrangement of the acceleration sensor of FIG. 1; [Diagram 3] FIG. 3(a) is a side view for explaining the heave acceleration and pitch angle of the center of gravity of the vehicle in FIG. 2, and FIG. 3(b) is a view of the vehicle seen from the rear for explaining the roll angle. [Figure 4] 3 is a diagram showing changes over time in state quantities and true values ​​of the state quantities obtained in the first arrangement of FIG. 2. [Diagram 5] FIG. 5 is a diagram showing the power spectral densities of the state quantities and the true values ​​of the state quantities in FIGS. [Figure 6] FIG. 13 is a diagram illustrating an example of a comparative example of an acceleration sensor arrangement. [Figure 7] 7 is a diagram showing changes over time in state quantities and true values ​​of the state quantities obtained in the arrangement of the comparative example in FIG. 6. [Figure 8] FIG. 8 is a diagram showing the power spectral densities of the state quantities and the true values ​​of the state quantities in FIGS. 7(a) to (c). [Figure 9] FIG. 13 is a diagram showing the relationship between the coefficients of the equation expressing the state quantity in the first arrangement and W3. [Figure 10] 2 is a diagram illustrating a second arrangement of the acceleration sensor of FIG. 1. FIG. [Figure 11] 11 is a diagram showing changes over time in state quantities and true values ​​of the state quantities obtained in the second arrangement of FIG. 10. FIG. [Figure 12] FIG. 12 is a diagram showing the power spectral densities of the state quantities and the true values ​​of the state quantities in FIGS. [Figure 13] FIG. 13 is a diagram showing the relationship between the coefficients of the equation expressing the state quantity in the second arrangement and L2a. [Figure 14] FIG. 2 is a diagram illustrating a third arrangement of the acceleration sensor of FIG. 1; [Figure 15] 15 is a diagram showing changes over time in state quantities and true values ​​of the state quantities obtained in the third arrangement of FIG. 14. [Figure 16] FIG. 16 is a diagram showing the power spectrum densities of the state quantities and the true values ​​of the state quantities of FIGS. 15(a) to (c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1 shows a configuration of a vehicle driving control system 1 according to an embodiment. The vehicle driving control system 1 is mounted on a vehicle such as an automobile and controls the driving of the vehicle. The vehicle may be a vehicle driven by a driver or may be an autonomous vehicle.

[0010] The vehicle driving control system 1 includes a first acceleration sensor 2a, a second acceleration sensor 2b, a third acceleration sensor 2c, and a control device 10. The first to third acceleration sensors 2a to 2c are collectively referred to as acceleration sensors 2. The three acceleration sensors 2 are installed on the sprung structure of the vehicle, detect vertical acceleration at their installation positions, and output information on the detected vertical acceleration to the control device 10. The vehicle driving control system 1 does not include any acceleration sensors that detect vertical acceleration other than the first to third acceleration sensors 2a to 2c. Therefore, costs can be reduced compared to the case where four acceleration sensors are provided.

[0011] The control device 10 controls the running of the vehicle based on the vertical acceleration detected by each of the three acceleration sensors 2. The control device 10 is also called an ECU (Electronic Control Unit). The control device 10 has a derivation unit 12 and a vehicle control unit 14.

[0012] The configuration of the control device 10 can be realized in hardware terms by the CPU, memory, and other LSI of any computer, and in software terms by programs loaded into memory, but here the functional blocks realized by the cooperation of these are depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by hardware alone, software alone, or a combination of both.

[0013] The derivation unit 12 derives the heave acceleration, roll angular acceleration, and pitch angular acceleration of the center of gravity of the vehicle's sprung structure based on the vertical accelerations detected by the first acceleration sensor 2a, the second acceleration sensor 2b, and the third acceleration sensor 2c. It can also be said that the derivation unit 12 converts the vertical accelerations detected by each of the three acceleration sensors 2 into heave acceleration, etc. The heave acceleration, roll angular acceleration, and pitch angular acceleration of the center of gravity are also called state quantities of the center of gravity. The derivation unit 12 supplies the derived state quantities to the vehicle control unit 14.

[0014] The vehicle control unit 14 controls the running of the vehicle 30 based on the derived heave acceleration, roll angular acceleration, and pitch angular acceleration of the center of gravity position g1. Known technologies can be used for the running control based on these state quantities. For example, the vehicle control unit 14 can further stabilize the posture of the vehicle and achieve a comfortable ride and handling stability by controlling the damping force of the shock absorbers of each suspension of the vehicle based on the state quantities.

[0015] The derivation unit 12 may derive the vertical acceleration of the sprung structure at the position of each wheel using a known technique based on the derived heave acceleration, roll angular acceleration, and pitch angular acceleration at the center of gravity position. In this case, the vehicle control unit 14 may control the running of the vehicle using a known technique based on the vertical acceleration at the position of each wheel.

[0016] In this embodiment, the three acceleration sensors 2 are arranged at positions where the accuracy of the derived state quantities can be improved. A first arrangement, a second arrangement, and a third arrangement of the three acceleration sensors 2 will be described below.

[0017] Figure 2 shows a schematic diagram of a first arrangement of the acceleration sensor 2 of Figure 1. Figure 2 shows a top view of a vehicle 30. A right front wheel 4a, a left front wheel 4b, a right rear wheel 4c, and a left rear wheel 4d of the vehicle 30 are collectively referred to as wheels 4.

[0018] The first acceleration sensor 2a is disposed at a position closer to the right front wheel 4a than the center of gravity position g1 of the sprung structure of the vehicle 30. The first acceleration sensor 2a is disposed near the right front wheel 4a. The distance from the center of gravity position g1 to the first acceleration sensor 2a in the vehicle width direction is defined as W1, and the distance from the center of gravity position g1 to the first acceleration sensor 2a in the vehicle front-rear direction is defined as L1. It is preferable that W1 and L1 are each large. This is because the accuracy of the state quantity of the center of gravity position g1 can be improved.

[0019] The second acceleration sensor 2b is disposed in a region different from the region in which the first acceleration sensor 2a is disposed, of two regions separated by an imaginary line 6 passing through the center of gravity position g1 in the vehicle longitudinal direction. Since the first acceleration sensor 2a is disposed in the region to the right of the imaginary line 6, the second acceleration sensor 2b is disposed in the region to the left of the imaginary line 6. The second acceleration sensor 2b is disposed near the left front wheel 4b.

[0020] The distance in the vehicle width direction from the center of gravity position g1 to the second acceleration sensor 2b is W2, and the distance in the vehicle front-rear direction from the center of gravity position g1 to the second acceleration sensor 2b is L2. It is preferable that W2 and L2 are each large, because this can improve the accuracy of the state quantity of the center of gravity position g1. Here, W1 and W2 are approximately equal, and L1 and L2 are approximately equal.

[0021] The third acceleration sensor 2c is disposed in a region different from the region in which the first acceleration sensor 2a is disposed, out of two regions separated by a virtual line 8 passing through the center of gravity position g1 in the vehicle width direction. Since the first acceleration sensor 2a is disposed in the region in front of the virtual line 8, the third acceleration sensor 2c is disposed in the region behind the virtual line 8.

[0022] The third acceleration sensor 2c is located between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction. In the illustrated example, the third acceleration sensor 2c is located at a middle position between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction.

[0023] The distance in the vehicle width direction from the center of gravity position g1 to the third acceleration sensor 2c is W3, and the distance in the vehicle front-rear direction from the center of gravity position g1 to the third acceleration sensor 2c is L3. It is preferable that L3 is large, because this can improve the accuracy of the state quantity of the center of gravity position g1. In the illustrated example, W3 is zero. In other words, the third acceleration sensor 2c is disposed on the virtual line 6.

[0024] FIG. 3(a) shows the heave acceleration z of the center of gravity g1 of the vehicle 30 in FIG. b and pitch angle θ y FIG. 3(b) is a side view for explaining the roll angle θ x FIG. 2 is a rear view of the vehicle 30 for explaining the above.

[0025] The first vertical acceleration z detected by the first acceleration sensor 2a s1 is the heave acceleration z of the center of gravity g1 b , pitch angular acceleration θ at center of gravity g1 y '', and the roll angular acceleration θ of the center of gravity g1 x The second vertical acceleration z detected by the second acceleration sensor 2b can be expressed by the following equation (1) using s2 can be expressed by the following equation (2), and the third vertical acceleration z s3 can be expressed by the following equation (3).

[0026]

number

[0027] Based on these equations (1) to (3), the heave acceleration z b , pitch angular acceleration θ y '', and roll angular acceleration θ x '' can be expressed by the following equations (4) to (6).

[0028]

number

[0029] The values ​​of W1, W2, W3, L1, L2, and L3 are stored in advance in a memory (not shown) of the control device 10. The derivation unit 12 calculates the first vertical acceleration z s1 , the second vertical acceleration z s2 , the third vertical acceleration z s3 , W1, W2, W3, L1, L2, L3, and based on equations (4) to (6), the heave acceleration z b , roll angular acceleration θ x '', and pitch angular acceleration θ y Derive ''.

[0030] In the first arrangement, W3 is zero, so "W3-W1" is -W1, which is not zero. Therefore, in the above-mentioned equation (6), the second vertical acceleration z s2 The coefficient of is not zero. The first vertical acceleration z in Eq. (6) s1 and the third vertical acceleration z s3 The coefficients of each of these are not zero. Therefore, the pitch angular acceleration θ y " is a value reflecting the vertical acceleration detected by each of the three acceleration sensors 2, which makes the error from the true value relatively small. The true value is obtained by placing an acceleration sensor near each of the four wheels 4 and converting the vertical acceleration detected by each of the four acceleration sensors into a state quantity of the center of gravity position g1 using a known conversion formula. The true value roughly coincides with the actual state quantity of the center of gravity position g1.

[0031] Also, since W3 is zero, "L3W2-L2W3" is L3W2, which is not zero. Therefore, in the above-mentioned formula (4), the first vertical acceleration z s1 The coefficient of is not zero. The second vertical acceleration z in Eq. (4) s2 and the third vertical acceleration z s3 The coefficients of each of these are also not zero. Therefore, the heave acceleration z b becomes a value reflecting the vertical acceleration detected by each of the three acceleration sensors 2, and thus the error from the true value becomes relatively small.

[0032] On the other hand, since L1 is approximately equal to L2, "L2-L1" is approximately zero. Therefore, in the above-mentioned formula (5), the third vertical acceleration z s3 The coefficient of is approximately zero. Therefore, the roll angular acceleration θ x '' is the detected third vertical acceleration z s3 Therefore, the error from the true value tends to become relatively large.

[0033] 4(a) to (c) show the time changes of the state quantities and the true values ​​of the state quantities obtained in the first arrangement of FIG. 2. FIG. 4(a) shows the time changes of the heave acceleration z b 4(b) shows the roll angular acceleration θ x '' and Fig. 4(c) shows the pitch angular acceleration θ y '' is indicated.

[0034] 4(a) to (c), the solid waveforms represent the state quantities obtained in the first arrangement, and the dashed waveforms represent the true values. These figures show the state quantities derived when the two left wheels 4 pass over a road surface with a step while the vehicle 30 is traveling at a predetermined speed.

[0035] heave acceleration z b and pitch angular acceleration θ y On the other hand, at time t1 when the left rear wheel 4d passes over the step, the roll angular acceleration θ x The error from the true value of '' becomes relatively large.

[0036] Figures 5(a) to (c) show the power spectrum density of the state quantities and the true values ​​of the state quantities in Figures 4(a) to (c). Figure 5(a) shows the heave acceleration z b 5(b) shows the power spectrum density of the roll angular acceleration θ x '' and Fig. 5(c) shows the power spectral density of the pitch angular acceleration θ y 1 shows the power spectral density of the state quantity in the first arrangement, and the dashed waveform represents the true value. The vertical axis of the graph represents the power spectral density of the state quantity in logarithm, and the horizontal axis represents frequency.

[0037] heave acceleration z b and pitch angular acceleration θ y The power spectral densities of '' and '' are in relatively good agreement with the true values. On the other hand, the roll angular acceleration θ x The power spectral density of '' has a relatively large error from the true value at some frequencies.

[0038] Here, the arrangement of the acceleration sensor 2 in the comparative example will be described. Fig. 6 shows a schematic arrangement of the acceleration sensor 2 in the comparative example. In the comparative example, the arrangement of the third acceleration sensor 2c is different from the first arrangement in Fig. 2, while the arrangements of the other two acceleration sensors 2 are the same as the first arrangement.

[0039] The third acceleration sensor 2c is disposed near the right rear wheel 4c. The third acceleration sensor 2c is not disposed between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, and W3 is equal to W1. In other words, "W3-W1" is zero. Therefore, in the above-mentioned equation (6), the second vertical acceleration z s2 The coefficient of becomes zero. Therefore, the pitch angular acceleration θ y '' is the second vertical acceleration z s2 becomes independent of the true value, resulting in a large error from the true value.

[0040] In addition, since W3 is approximately equal to W2, and L3 is approximately equal to L2, "L3W2-L2W3" is approximately zero. Therefore, in the above-mentioned formula (4), the first vertical acceleration z s1 The coefficient of is almost zero. Therefore, the heave acceleration z b is the first vertical acceleration z s1 becomes almost unrelated to the true value, and the error from the true value becomes large.

[0041] Roll angular acceleration θ x ″ is the third vertical acceleration z detected by the third acceleration sensor 2c, similarly to the first arrangement of the embodiment. s3 becomes almost unrelated to the true value, and the error from the true value becomes large.

[0042] 7(a) to (c) show the time changes of the state quantities and the true values ​​of the state quantities obtained in the arrangement of the comparative example of FIG. 6. FIG. 7(a) shows the time changes of the heave acceleration z b 7(b) shows the roll angular acceleration θ x '' and Fig. 7(c) shows the pitch angular acceleration θ y '' is indicated.

[0043] heave acceleration z b and pitch angular acceleration θ y The errors from the true values ​​of the roll angular acceleration θ′′ are larger than those in the embodiment, and the errors become larger at time t1 when the left rear wheel 4d passes over the step. x The error of '' is the same as that of the embodiment. At time t1, the heave acceleration z b The absolute value of increases by about 40%, and the roll angular acceleration θ x The absolute value of '' becomes about 20% larger, and the pitch angular acceleration θ y The absolute value of '' is about 55% larger.

[0044] 8(a) to (c) show the power spectrum density of the state quantities and the true values ​​of the state quantities in FIG. 7(a) to (c). FIG. 8(a) shows the heave acceleration z b 8(b) shows the power spectrum density of the roll angular acceleration θ x '' and Fig. 8(c) shows the power spectral density of the pitch angular acceleration θ y '' shows the power spectral density of

[0045] The power spectrum density is also compared with the true value, and the heave acceleration z b The roll angular acceleration θ x '' is about 3 dB larger, and the pitch angular acceleration θ y '' is about 3 dB louder.

[0046] In contrast to these comparative examples, according to the first arrangement of the embodiment, as described above, the heave acceleration z b and pitch angular acceleration θ yEach of the '' is closer to the true value and has improved accuracy.

[0047] However, W3 is not limited to zero, and if the third acceleration sensor 2c is disposed between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, the accuracy of the derived state quantity will be higher than in the comparative example where W3=W1, and the closer to the intermediate position between them, the higher the accuracy will be. Therefore, an example of a preferable range of W3 will be described.

[0048] heave acceleration z b In the formula (4) expressing the first vertical acceleration z s1 The coefficient of h1, the second vertical acceleration z s2 The coefficient of h2, the third vertical acceleration z s3 With the coefficient of h3, equation (4) can be expressed as the following equation (7). These coefficients can also be called conversion coefficients.

[0049] z b =h1 z s1 +h2·z s2 +h3·z s3 Formula (7)

[0050] Roll angular acceleration θ x In the formula (5) expressing '', the first vertical acceleration z s1 The coefficient of r1, the second vertical acceleration z s2 The coefficient of r2, the third vertical acceleration z s3 With the coefficient of r3, equation (5) can be expressed as the following equation (8).

[0051] θ x ''=r1·z s1 +r2·z s2 +r3·z s3 Formula (8)

[0052] Pitch angular acceleration θ y In the equation (6) expressing the first vertical acceleration z s1 The coefficient of p1, the second vertical acceleration z s2 The coefficient of p2, the third vertical acceleration z s3With the coefficient of p3, equation (6) can be expressed as the following equation (9).

[0053] θ y ''=p1·z s1 +p2·z s2 +p3·z s3 Formula (9)

[0054] 9(a) to (c) show the relationship between the coefficients of the equations expressing the state quantities in the first configuration and W3. b The coefficients h1, h2, and h3 in equation (7) are shown in FIG. 9(b). x The coefficients r1, r2, and r3 in equation (8) that expresses the pitch angular acceleration θ y The coefficients p1, p2, and p3 of equation (9) representing

[0055] In these relationships, in the first arrangement, W1, W2, L1, L2, and L3 are constant, and W3 is varied. The vertical axis of these figures represents the coefficient value, and the horizontal axis represents W3. When the third acceleration sensor 2c is arranged to the right of the imaginary line 6 in FIG. 2, W3 is a positive value, and when the third acceleration sensor 2c is arranged to the left of the imaginary line 6, W3 is a negative value. The value of W1 is also a1. In other words, W3=a1 represents the arrangement of the comparative example.

[0056] As shown in Figure 9(a), the heave acceleration z b Regarding the above, as W3 becomes smaller, the coefficient h2 becomes smaller and the coefficient h1 becomes larger. In other words, the coefficients h1 and h2 are determined according to the position of the third acceleration sensor 2c in the vehicle width direction. When W3=0, the coefficients h1 and h2 are approximately equal. The coefficient h3 is a constant value independent of W3.

[0057] Similarly, as shown in FIG. 9(c), the pitch angular acceleration θ yRegarding "," as W3 becomes smaller, coefficient p2 becomes smaller and coefficient p1 becomes larger. In other words, coefficients p1 and p2 are determined according to the position of the third acceleration sensor 2c in the vehicle width direction. When W3=0, coefficients p1 and p2 are approximately equal. Coefficient p3 is a constant value independent of W3.

[0058] As shown in FIG. 9(b), the roll angular acceleration θ x Regarding , the coefficients r1, r2, and r3 are constant values ​​independent of W3.

[0059] 9(a) and (c), if W3 is smaller than a1, that is, if the third acceleration sensor 2c is disposed between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, the absolute values ​​of the coefficients h1 and p2 become larger than in the comparative example where W3=W1=a1. Therefore, the accuracy of the derived state quantities becomes higher than in the comparative example.

[0060] The smaller the difference in absolute value between the coefficients h1, h2, and h3, the greater the heave acceleration z b Similarly, the smaller the difference in absolute value between the coefficients p1, p2, and p3, the higher the accuracy of the pitch angular acceleration θ y '' will be more accurate. Therefore, in this example, W3=0 is the most accurate.

[0061] Here, assuming that the third acceleration sensor 2c is located at an intermediate position between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, i.e., assuming that W3=0, the value of the coefficient p1 is set to the first reference value.

[0062] For example, if the coefficient p1 is within the range of ±33% of the first reference value, the pitch angular acceleration θ y Therefore, the position of the third acceleration sensor 2c in the vehicle width direction may be determined so that the coefficient p1 falls within the range of ±33% of the first reference value.

[0063] W3 is calculated from equation (6) when coefficient p1 is +33% of the first reference value, and the calculated value is designated as -a3. W3 is calculated from equation (6) when coefficient p1 is -33% of the first reference value, and the calculated value is designated as a2. In this case, W3 may be set in the range from -a3 to a2. W3 being in the range from -a3 to a2 corresponds to the third acceleration sensor 2c being disposed near the middle position between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction.

[0064] In addition, the value of the coefficient p2 when it is assumed that the third acceleration sensor 2c is located at the intermediate position between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, that is, when it is assumed that W3=0, may be set as the second reference value. W3 when the coefficient p2 is a value of +33% of the second reference value is obtained from the formula (6), and the obtained value is set as a4 (not shown). W3 when the coefficient p2 is a value of -33% of the second reference value is obtained from the formula (6), and the obtained value is set as -a5 (not shown). In this case, W3 may be set in the range from the larger of -a3 and -a5 to the smaller of a2 and a4. It is assumed that -a3 and -a5 are equivalent values, and a2 and a4 are also equivalent values.

[0065] The range of ±33% is an example range determined based on the 67% credible interval. The range of ±33% can be appropriately determined by experiments or simulations depending on the required accuracy of the state quantity, and may be, for example, a range narrower than ±33% or a range wider than ±33%.

[0066] Even if the installation position of the third acceleration sensor 2c is limited due to the structure of the vehicle 30 and it is not possible to install it at a position where W3=0, by installing the third acceleration sensor 2c at a position where W3 is included in the range from -a3 to a2, it is possible to obtain a relatively high-precision heave acceleration z b and pitch angular acceleration θ y '' can be obtained.

[0067] As described above, according to the first arrangement of the embodiment, by making W3 different from W1, the heave acceleration z b and pitch angular acceleration θ y '' can be derived. Therefore, the heave acceleration z b and pitch angular acceleration θ y '' can improve the accuracy of each.

[0068] In addition, by positioning the third acceleration sensor 2c near the midpoint between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction, the difference in absolute value between the coefficients can be made smaller, and the accuracy of the state quantities can be improved. By positioning the third acceleration sensor 2c at the midpoint, the accuracy of the state quantities can be further improved.

[0069] Therefore, by using the three acceleration sensors 2 arranged on the vehicle 30, the state quantity of the center-of-gravity position g1 can be obtained with higher accuracy.

[0070] (Second Arrangement of Acceleration Sensor 2) Next, another arrangement of the acceleration sensor 2 will be described. The following mainly describes the differences from the first arrangement.

[0071] FIG. 10 shows a schematic diagram of a second arrangement of the acceleration sensor 2 in FIG. 1. The arrangement of the first acceleration sensor 2a is the same as the first arrangement. The arrangement of the third acceleration sensor 2c is the same as the comparative example, and is arranged near the right rear wheel 4c. W1 is equal to W3. L3 is the same as the first arrangement.

[0072] The second acceleration sensor 2b is disposed rearward of the first arrangement. The second acceleration sensor 2b is disposed between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction. In the illustrated example, the second acceleration sensor 2b is located at an intermediate position between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction. The second acceleration sensor 2b is disposed near the imaginary line 8, slightly rearward of the imaginary line 8. W2 is the same as the first arrangement. Note that, when L3 is equal to L1, L2 may be zero, and the second acceleration sensor 2b may be disposed on the imaginary line 8.

[0073] In the above-described equations (1) to (6), when the second acceleration sensor 2b is placed behind the imaginary line 8, L2 is a negative value, and when the second acceleration sensor 2b is placed in front of the imaginary line 8, L2 is a positive value.

[0074] In the second configuration, L2 is different from L1, so "L2-L1" is not zero. Therefore, in the above-mentioned equation (5), the third vertical acceleration z s3 The coefficient of is not zero. The first vertical acceleration z in Eq. (5) s1 and the second vertical acceleration z s2 The coefficients of each of these are not zero. Therefore, the roll angular acceleration θ x '' is a value reflecting the vertical acceleration detected by each of the three acceleration sensors 2, and this makes the error from the true value relatively small.

[0075] In addition, in the above-mentioned formula (4), the first vertical acceleration z s1 , the second vertical acceleration z s2 , and a third vertical acceleration z s3 Each coefficient is not zero. Therefore, the heave acceleration z b becomes a value reflecting the vertical acceleration detected by each of the three acceleration sensors 2, and thus the error from the true value becomes relatively small.

[0076] On the other hand, since W1 is equal to W3, "W3-W1" is zero. Therefore, in the above-mentioned equation (6), the second vertical acceleration zs2 The coefficient of becomes zero. Therefore, the pitch angular acceleration θ y '' is the detected second vertical acceleration z s2 As a result, similar to the comparative example, the error from the true value tends to become relatively large.

[0077] 11(a) to (c) show the time changes of the state quantities and the true values ​​of the state quantities obtained in the second arrangement of FIG. 10. FIG. 11(a) shows the time changes of the heave acceleration z b FIG. 11(b) shows the roll angular acceleration θ x '' and Fig. 11(c) shows the pitch angular acceleration θ y '' is indicated.

[0078] In Fig. 11(a) to (c), the solid waveforms represent the state quantities obtained in the second arrangement, and the dashed waveforms represent the true values. These figures also show the state quantities derived under the same conditions as Fig. 4(a) to (c).

[0079] heave acceleration z b and roll angular acceleration θ x Each of the pitch angular accelerations θ ′ ... y The error from the true value of '' is equivalent to that of the comparative example.

[0080] 12(a) to 12(c) show the power spectrum density of the state quantities and the true values ​​of the state quantities in FIG. 11(a) to 11(c). FIG. 12(a) shows the heave acceleration z b 11(b) shows the power spectrum density of the roll angular acceleration θ x '' and Fig. 12(c) shows the power spectral density of the pitch angular acceleration θ y '' shows the power spectral density of

[0081] heave acceleration z b and roll angular acceleration θ x The power spectral densities of θ′ and θ′ are in relatively good agreement with the true values, which is an improvement over the comparative example. On the other hand, the pitch angular acceleration θ yIn the power spectral density of '', the error from the true value is equivalent to that of the comparative example.

[0082] However, the second acceleration sensor 2b does not have to be located at the intermediate position between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction. If the second acceleration sensor 2b is located between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction, the accuracy of the derived state quantity will be higher than in the comparative example where L2=L1, and the closer to the intermediate position, the higher the accuracy will be. Therefore, an example of a preferable range of L2 will be described.

[0083] Figure 13(a) to (c) show the coefficients of the equations expressing the state quantities in the second configuration and L 2a This shows the relationship between L 2a L represents the distance in the vehicle longitudinal direction from an imaginary line passing through the center of the left front wheel 4b and the center of the right front wheel 4a, and is used for convenience of explanation. 2a can be transformed to L2 using the coordinates of the center of gravity g1.

[0084] Figure 13(a) shows the heave acceleration z b The coefficients h1, h2, and h3 in equation (7) are shown in FIG. 13(b). x The coefficients r1, r2, and r3 in equation (8) representing the pitch angular acceleration θ y The coefficients p1, p2, and p3 of equation (9) representing

[0085] In these relationships, in the second arrangement, W1, W2, W3, L1, and L3 are constant, and L 2a This is equivalent to changing L2. The vertical axis of these figures represents the coefficient value, and the horizontal axis represents L 2a It represents L1. 2a Let the value of b1. That is, L 2a =b1 shows the arrangement of the comparative example. Also, L at the midpoint between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle front-rear direction 2a Let the value be b4.

[0086] As shown in Figure 13(a), the heave acceleration z b Regarding L 2a As L increases, the coefficient h1 increases and the coefficient h3 decreases. In other words, the coefficients h1 and h3 are determined according to the position of the second acceleration sensor 2b in the vehicle front-rear direction. 2a When b4, the coefficients h1 and h3 are almost equal. The coefficient h2 is 2a is a constant value independent of

[0087] Similarly, as shown in FIG. 13(b), the roll angular acceleration θ x Regarding ''L 2a In other words, the coefficients r1 and r3 are determined according to the position of the second acceleration sensor 2b in the vehicle front-rear direction. 2a In the case of b4, the absolute values ​​of coefficients r1 and r3 are almost equal. 2a is a constant value independent of

[0088] As shown in FIG. 13(c), the pitch angular acceleration θ y Regarding '', the coefficients p1, p2, and p3 are L 2a is a constant value independent of

[0089] From Fig. 13(a) and (b), L 2a If L is greater than b1, that is, if the second acceleration sensor 2b is disposed between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction, L 2a It can be seen that the absolute values ​​of the coefficients h1 and r3 are larger than those in the comparative example where =b1. Therefore, the accuracy of the derived state quantities is higher than that in the comparative example.

[0090] The smaller the difference in absolute value between the coefficients h1, h2, and h3, the greater the heave acceleration z b Similarly, the smaller the difference in absolute value between the coefficients r1, r2, and r3, the higher the accuracy of the roll angular acceleration θ x '' will be more accurate. So, in this example, L 2a =b4 is the most accurate.

[0091] Here, assuming that the second acceleration sensor 2b is located at a midpoint between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle front-rear direction, that is, L 2a The value of coefficient r1 when it is assumed that b4=b1 is the third reference value.

[0092] For example, if the coefficient r1 is within the range of ±33% of the third reference value, the roll angular acceleration θ x Therefore, the position of the second acceleration sensor 2b in the vehicle longitudinal direction may be determined so that the coefficient r1 falls within the range of ±33% of the third reference value.

[0093] L when coefficient r1 is +33% of the third reference value 2a is calculated from equation (5), and the calculated value is b3. L when coefficient r1 is -33% of the third reference value 2a is calculated from equation (5) and the calculated value is b2. In this case, L 2a may be determined to be in the range from b2 to b3. 2a is included in the range from b2 to b3, this corresponds to the second acceleration sensor 2b being disposed near the middle position between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle front-rear direction.

[0094] In addition, if it is assumed that the second acceleration sensor 2b is located at a middle position between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle front-rear direction, that is, L 2a The value of the coefficient r3 when it is assumed that the coefficient r3 is equal to or larger than the fourth reference value, b4, may be set as the fourth reference value. 2a is calculated from the formula (5), and the calculated value is designated as b5 (not shown). 2a is calculated from equation (5), and the calculated value is designated as b6 (not shown). In this case, L 2a may be set in the range from the larger of b2 and b5 to the smaller of b3 and b6, where it is assumed that b2 and b5 are equal in value, and that b3 and b6 are also equal in value.

[0095] The location where the second acceleration sensor 2b is installed is limited due to the structure of the vehicle 30, etc. 2a Even if it cannot be placed at the b4 position, L 2a By installing the second acceleration sensor 2b at a position included in the range from b2 to b3, the heave acceleration z b and roll angular acceleration θ x '' can be obtained.

[0096] According to the second arrangement, by making L2 different from L1, the heave acceleration z b and roll angular acceleration θ x '' can be derived, improving the accuracy of these.

[0097] In addition, by positioning the second acceleration sensor 2b near the midpoint between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle longitudinal direction, the difference in absolute value between the coefficients can be made smaller, and the accuracy of the state quantities can be improved. By positioning the second acceleration sensor 2b at the midpoint, the accuracy of the state quantities can be further improved.

[0098] (Third Arrangement of Acceleration Sensor 2) Next, a description will be given of yet another arrangement of the acceleration sensor 2. The following description will focus on the differences from the first arrangement.

[0099] Figure 14 shows a schematic diagram of a third arrangement of the acceleration sensor 2 in Figure 1. The third arrangement is a combination of the first and second arrangements. That is, the arrangement of the first acceleration sensor 2a and the third acceleration sensor 2c is the same as the first arrangement, and the arrangement of the second acceleration sensor 2b is the same as the second arrangement.

[0100] 15(a) to (c) show the time changes of the state quantities and the true values ​​of the state quantities obtained in the third arrangement of FIG. 14. FIG. 15(a) shows the time changes of the heave acceleration z b FIG. 15(b) shows the roll angular acceleration θ x'' and Fig. 15(c) shows the pitch angular acceleration θ y '' is indicated.

[0101] In Fig. 15(a) to (c), the solid waveforms represent the state quantities obtained in the third arrangement, and the dashed waveforms represent the true values. These figures also show the state quantities derived under the same conditions as Fig. 4(a) to (c).

[0102] heave acceleration z b , roll angular acceleration θ x '', and pitch angular acceleration θ y Each of the values ​​is roughly consistent with the true value and is an improvement over the comparative example.

[0103] 16(a) to 16(c) show the power spectrum density of the state quantities and the true values ​​of the state quantities in FIG. 15(a) to 15(c). FIG. 16(a) shows the power spectrum density of the heave acceleration z b 16(b) shows the power spectrum density of the roll angular acceleration θ x '' and Fig. 16(c) shows the power spectrum density of the pitch angular acceleration θ y '' shows the power spectral density of

[0104] heave acceleration z b , roll angular acceleration θ x '', and pitch angular acceleration θ y Each of the power spectral densities of '' are in relatively good agreement with the true values, an improvement over the comparative example.

[0105] According to the third arrangement, the effects of the first arrangement and the second arrangement are combined. In other words, by making W3 different from W1 and making L2 different from L1, the heave acceleration z b , roll angular acceleration θ x '', and pitch angular acceleration θ y '' can be derived, improving the accuracy of these.

[0106] Among the above first to third arrangements, when both the ride comfort and the driving stability of the vehicle are to be improved, the roll angular acceleration θ x '' and pitch angular acceleration θ y It is preferable to adopt the third arrangement, which can improve the accuracy of ''.

[0107] On the other hand, when the third arrangement cannot be adopted due to restrictions on the installation position of the acceleration sensor 2 due to the structure of the vehicle 30, the first arrangement or the second arrangement may be adopted. For example, in order to improve the ride comfort of the vehicle 30, y In order to improve the driving stability of the vehicle 30, the roll angular acceleration θ x A second arrangement may be adopted that can improve the accuracy of ''.

[0108] In other words, at least one of the following conditions must be satisfied: a first condition that the third acceleration sensor 2c is located between the first acceleration sensor 2a and the second acceleration sensor 2b in the vehicle width direction; and a second condition that the second acceleration sensor 2b is located between the first acceleration sensor 2a and the third acceleration sensor 2c in the vehicle front-rear direction.

[0109] The present invention has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present invention.

[0110] For example, the three acceleration sensors 2 may be arranged in the first arrangement described above, but may be swapped with respect to the imaginary line 8. In other words, the first acceleration sensor 2a may be arranged near the right rear wheel 4c, the second acceleration sensor 2b may be arranged near the left rear wheel 4d, and the third acceleration sensor 2c may be arranged in front of the imaginary line 8.

[0111] The arrangement of the three acceleration sensors 2 may be interchanged with respect to the virtual line 6 in the above-mentioned second arrangement. That is, in the second arrangement, the first acceleration sensor 2a may be arranged near the left front wheel 4b, the second acceleration sensor 2b may be arranged to the right of the virtual line 6, and the third acceleration sensor 2c may be arranged near the left rear wheel 4d.

[0112] The arrangement of the three acceleration sensors 2 may be reversed with respect to the virtual line 8 in the above-mentioned third arrangement, or may be reversed with respect to the virtual line 6, or may be a combination of these. For example, when the front and rear are reversed with respect to the virtual line 8, the first acceleration sensor 2a may be disposed near the right rear wheel 4c, the second acceleration sensor 2b may be disposed to the left of the virtual line 6, and the third acceleration sensor 2c may be disposed in front of the virtual line 8. When the left and right are reversed with respect to the virtual line 6, the first acceleration sensor 2a may be disposed near the left front wheel 4b, the second acceleration sensor 2b may be disposed to the right of the virtual line 6, and the third acceleration sensor 2c may be disposed behind the virtual line 8. When the front and rear are reversed with respect to the virtual line 8 and the left and right are reversed with respect to the virtual line 6, the first acceleration sensor 2a may be disposed near the left rear wheel 4d, the second acceleration sensor 2b may be disposed to the right of the virtual line 6, and the third acceleration sensor 2c may be disposed in front of the virtual line 8.

[0113] These modified arrangements can be adopted when there are restrictions on the installation position of the acceleration sensor 2 due to the structure of the vehicle 30. These modified arrangements allow the acceleration sensor 2 to be arranged in an appropriate position according to the structure of the vehicle 30, and the effects of the embodiment described above can be obtained. [Explanation of symbols]

[0114] 1...vehicle driving control system, 2...acceleration sensor, 2a...first acceleration sensor, 2b...second acceleration sensor, 2c...third acceleration sensor, 4...wheel, 10...control device, 12...derivation section, 14...vehicle control section, 30...vehicle.

Claims

1. a first acceleration sensor that detects vertical acceleration and is disposed at a position closer to one of the wheels than the center of gravity of a sprung structure of the vehicle; a second acceleration sensor that detects vertical acceleration and is disposed in a region different from the region in which the first acceleration sensor is disposed, out of two regions that are partitioned by a virtual line passing through the center of gravity position in a vehicle longitudinal direction; a third acceleration sensor that detects vertical acceleration and is disposed in a region different from the region in which the first acceleration sensor is disposed, out of two regions that are partitioned by a virtual line passing through the center of gravity position in a vehicle width direction; and a control device that derives a heave acceleration, a roll angular acceleration, and a pitch angular acceleration of the center-of-gravity position based on the vertical accelerations detected by the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor, respectively; Equipped with a first condition that the third acceleration sensor is located between the first acceleration sensor and the second acceleration sensor in a vehicle width direction; At least one of the second conditions is satisfied: the second acceleration sensor is located between the first acceleration sensor and the third acceleration sensor in the vehicle front-rear direction; the first condition includes that the third acceleration sensor is located near a middle position between the first acceleration sensor and the second acceleration sensor in a vehicle width direction; the second condition includes that the second acceleration sensor is located near a middle position between the first acceleration sensor and the third acceleration sensor in a vehicle front-rear direction; The vertical acceleration detected by the first acceleration sensor is z s1 , the vertical acceleration detected by the second acceleration sensor is z s2 , the vertical acceleration detected by the third acceleration sensor is z s3 , and p1, p2, and p3 are coefficients. The control device derives p1·z s1 +p2·z s2 +p3·z s3 as the pitch angular acceleration, p1 is determined according to the position of the third acceleration sensor in the vehicle width direction, The value of p1 when it is assumed that the third acceleration sensor is located at an intermediate position between the first acceleration sensor and the second acceleration sensor in the vehicle width direction is set as a reference value, a position of the third acceleration sensor in the vehicle width direction is determined so that p1 is within a range of ±33% of the reference value when the first condition is satisfied; A vehicle driving control system comprising:

2. A first acceleration sensor that detects vertical acceleration and is disposed at a position closer to one of the wheels than the center of gravity of a sprung structure of a vehicle; a second acceleration sensor that detects vertical acceleration and is disposed in a region different from the region in which the first acceleration sensor is disposed, out of two regions that are partitioned by a virtual line passing through the center of gravity position in a vehicle longitudinal direction; a third acceleration sensor that detects vertical acceleration and is disposed in a region different from the region in which the first acceleration sensor is disposed, out of two regions that are partitioned by a virtual line passing through the center of gravity position in a vehicle width direction; and a control device that derives a heave acceleration, a roll angular acceleration, and a pitch angular acceleration of the center-of-gravity position based on the vertical accelerations detected by the first acceleration sensor, the second acceleration sensor, and the third acceleration sensor, respectively; Equipped with a first condition that the third acceleration sensor is located between the first acceleration sensor and the second acceleration sensor in a vehicle width direction; At least one of the second conditions is satisfied: the second acceleration sensor is located between the first acceleration sensor and the third acceleration sensor in the vehicle front-rear direction; the first condition includes that the third acceleration sensor is located near a middle position between the first acceleration sensor and the second acceleration sensor in a vehicle width direction; the second condition includes that the second acceleration sensor is located near a middle position between the first acceleration sensor and the third acceleration sensor in a vehicle front-rear direction; The vertical acceleration detected by the first acceleration sensor is z ｓ１ The vertical acceleration detected by the second acceleration sensor is z ｓ２ The vertical acceleration detected by the third acceleration sensor is z ｓ３ Let r1, r2, and r3 be coefficients. The control device is a control device for controlling r1·z ｓ１ +r2 z ｓ２ +r3 z ｓ３ is derived as the roll angular acceleration, r1 is determined according to the position of the second acceleration sensor in the vehicle longitudinal direction, The value of r1 when it is assumed that the second acceleration sensor is located at a midpoint between the first acceleration sensor and the third acceleration sensor in the vehicle front-rear direction is set as a reference value, a position of the second acceleration sensor in the vehicle longitudinal direction is determined so that r1 is within a range of ±33% of the reference value when the second condition is satisfied; A vehicle driving control system comprising:

3. No acceleration sensor for detecting vertical acceleration is provided other than the first to third acceleration sensors.

3. The vehicle driving control system according to claim 1 or 2.

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