AUTOMOBILE SPEED MEASUREMENT AND CONTROL METHOD AND SYSTEM

Abstract

By measuring speeds and deflection angles of two front wheels in real time, and according to values of gravity sensors at four wheel axles, and an axle base and a wheel base of an automobile, a center of gravity of the automobile is determined; moving speeds of the left and right front wheels of the automobile around an instantaneous center during cornering are converted into moving speeds at the center of gravity of the automobile respectively, and an average value of the two automobile speeds at the center of gravity of the automobile is taken as an actual driving speed of the vehicle during cornering; meanwhile, an automobile speed may be controlled according to force conditions of four wheels.

Claims

1. An automobile speed measurement method, comprising: A. obtaining inherent parameters of a four-wheel automobile, the inherent parameters of the automobile comprising an axle base L of the automobile, and a wheel base B of the automobile; measuring and obtaining gravity values F.sub.1, F.sub.2, F.sub.3 and F.sub.4 of four gravity sensors respectively mounted on a left front wheel, a right front wheel, a right rear wheel, and a left rear wheel in real time, and measuring a deflection angle .sub.1 and a speed v.sub.1 of the left front wheel, and a deflection angle .sub.2 and a speed v.sub.2 of the right front wheel in real time, a distance between a center of gravity G of the automobile and a connecting line of axes of the right front wheel and the right rear wheel being a, and a distance between the center of gravity G and a connecting line of axes of two left front wheels being b; B. calculating a distance a between the center of gravity G and the connecting line of axes of the front wheel at the opposite side and the rear wheel at the opposite side, a calculation formula being: $a=\frac{\left(F_1+F_4\right).Math.B}{F_1+F_2+F_3+F_4};$ C. calculating a distance b between the center of gravity G and the connecting line of axes of the two front wheels, a calculation formula being: $b=\frac{\left(F_3+F_4\right).Math.L}{F_1+F_2+F_3+F_4};$ D. determining the deflection angles and deflection directions of the front wheels of the automobile, the automobile speed at the center of gravity of the automobile being determined according to the average value of the speed v.sub.1 of the left front wheel and the speed v.sub.2 of the right front wheel of the automobile when an average value of the deflection angles of the left and right front wheels is smaller than 2; calculating the speed at the center of gravity of the automobile based on the left front wheel and the right front wheel respectively according to a steering state of the automobile when the average value of the deflection angles of the left and right front wheels is greater than or equal to 2; E. calculating a speed v.sub.G1 at the center of gravity of the automobile based on the left front wheel: {circle around (1)}. calculating a distance r.sub.1 between the left front wheel and an instantaneous center O, a calculation formula being: $r_1=\frac{L}{\sin .Math..Math.\left({}_1\right)};$ {circle around (2)}. calculating an angle .sub.G of the center of gravity formed among the center of gravity G of the automobile, the instantaneous center O, and a shaft axis of the rear wheel, a calculation formula being: ${}_G={\tan }^{-1}\left(\frac{L-b}{r_1.Math.\cos .Math..Math.\left({}_1\right)+i.Math.\left(B-a\right)}\right),$ wherein when the automobile turns left, i=1, and when the automobile turns right, i=1; {circle around (3)}. calculating a distance r.sub.G between the instantaneous center O and the center of gravity G, a calculation formula being: $r_G=\frac{L-b}{\sin .Math..Math.\left({}_G\right)};$ and {circle around (4)}. calculating the speed v.sub.G1 at the center of gravity of the automobile, a calculation formula being: $v_{G.Math..Math.1}=\frac{v_1}{r_1}.Math.r_G;$ F. calculating a speed v.sub.G2 at the center of gravity of the automobile based on the right front wheel: {circle around (1)}. calculating a distance r.sub.2 between the right front wheel and the instantaneous center O, wherein a calculation formula being: $r_2=\frac{L}{\sin .Math..Math.\left({}_2\right)};$ {circle around (2)}. calculating an angle .sub.G of the center of gravity formed among the center of gravity G of the automobile, the instantaneous center O, and a shaft axis of the rear wheel, a calculation formula being: ${}_G={\tan }^{-1}\left(\frac{L-b}{r_2.Math.\cos .Math..Math.\left({}_2\right)-i.Math.a}\right),$ wherein when the automobile turns left, i=1, and when the automobile turns right, i=1; {circle around (3)}. calculating a distance r.sub.G between the instantaneous center O and the center of gravity G, a calculation formula being: $r_G=\frac{L-b}{\sin .Math..Math.\left({}_G\right)};$ and {circle around (3)}. calculating the speed v.sub.G2 at the center of gravity of the automobile, a calculation formula being: $v_{G.Math..Math.2}=\frac{v_2}{r_2}.Math.r_G;$ and G. calculating an average automobile speed v.sub.G at the center of gravity of the automobile during steering, which is: $v_{G.Math.}=\frac{v_{G.Math..Math.1}+v_{G.Math..Math.2}}{2}.$

2. An automobile speed control method based on the automobile speed measurement method according to claim 1, wherein when the automobile speed is v.sub.G8 m/s, a ratio K of a maximum gravity value to a minimum gravity value in the four gravity sensors is calculated, wherein K=F.sub.max/F.sub.min, and when K10, an automobile speed controller controls the automobile to slow down, so that the ratio K of the maximum gravity value to the minimum gravity value detected by the four gravity sensors is smaller than 5.

3. The automobile speed control method according to claim 2, wherein when 10>K5 or |v.sub.G1v.sub.G2|/v.sub.G0.1, the automobile speed controller alarms through an alarm.

4. An automobile speed measurement and control system based on the automobile speed control method according to claim 2, comprising an automobile speed controller, wheel deflection measuring instruments mounted on two front wheels of an automobile, gravity sensors mounted on four wheel axles, and wheel speed measuring instruments mounted on the two front wheels of the automobile, wherein the wheel deflection measuring instruments, the wheel speed measuring instruments and the gravity sensors are all electrically connected to the automobile speed controller.

5. The automobile speed measurement and control system according to claim 4, wherein the automobile speed measurement and control system further comprises an alarm, wherein the alarm is connected to the automobile speed controller, the alarm comprises a sound alarm and/or a light alarm, the sound alarm is mounted in a driving cab, and the light alarm is mounted on an instrument panel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a structural block diagram of an automobile speed measurement and control system according to the present invention;

[0020] FIG. 2 is another structural block diagram of the automobile speed measurement and control system according to the present invention;

[0021] FIG. 3 is a parameter schematic diagram of the present invention when an automobile turns left; and

[0022] FIG. 4 is a parameter schematic diagram of the present invention when the automobile turns right;

[0023] in the figures: 1 refers to automobile speed controller, 2 refers to wheel deflection measuring instrument, 3 refers to gravity sensors 4 refers to wheel speed measuring instrument, and 5 refers to alarm.

DETAILED DESCRIPTION

[0024] The technical solutions of the present invention will be further described in details hereunder with reference to the embodiments and drawings.

Embodiment 1

[0025] In the embodiment 1 as shown in FIG. 1, an automobile speed measurement and control system includes an automobile speed controller 1, wheel deflection measuring instruments 2 mounted on two front wheels of an automobile, gravity sensors 3 mounted on four wheel axles, and wheel speed measuring instruments 4 mounted on the two front wheels of the automobile. The wheel deflection measuring instruments are respectively mounted on the left front wheel and the right front wheel of the automobile, and are used for measuring a deflection angle .sub.1 of the left front wheel and a deflection angle .sub.2 of the right front wheel of the automobile during cornering; and the wheel speed measuring instruments are respectively mounted on the left front wheel and the right front wheel of the automobile to measure a real time speed v.sub.1 of the left front wheel and a real time speed v.sub.2 of the right front wheel of the automobile, and four gravity sensors are provided, which are respectively mounted on the four wheel axles to measure the gravities or pressures borne by the four wheel axles. The wheel deflection measuring instruments, the wheel speed measuring instruments and the gravity sensors are all electrically connected to the automobile speed controller. The automobile speed controller is connected to a brake system and an engine system of the automobile, and the automobile speed may be intelligently reduced through the brake system and the engine system. A value detected by the gravity sensor mounted on the wheel axle of the left front wheel is F.sub.1, a value detected by the gravity sensor mounted on the wheel axle of the right front wheel is F.sub.2, a value detected by the gravity sensor mounted on the right rear wheel is F.sub.3, and a value detected by the gravity sensor mounted on the wheel axle of the left rear wheel is F.sub.4.

[0026] An automobile speed measurement method of the automobile speed measurement and control system according to the present invention includes the following steps of:

A. obtaining inherent parameters of a four-wheel automobile, the inherent parameters of the automobile including an axle base L of the automobile, and a wheel base B of the automobile; measuring and obtaining gravity values F.sub.1, F.sub.2, F.sub.3 and F.sub.4 of four gravity sensors respectively mounted on a left front wheel, a right front wheel, a right rear wheel, and a left rear wheel in real time, and measuring a deflection angle .sub.1 and a speed v.sub.1 of the left front wheel, and a deflection angle .sub.2 and a speed v.sub.2 of the right front wheel in real time, a distance between a centre of gravity G of the automobile and a connecting line of axes of the right front wheel and the right rear wheel being a, and a distance between the centre of gravity G and a connecting line of axes of two left front wheels being b;
B. calculating a distance a between the centre of gravity G and the connecting line of axes of the front wheel at the opposite side and the rear wheel at the opposite side, a calculation formula being:

[00012]$a=\frac{\left(F_1+F_4\right).Math.B}{F_1+F_2+F_3+F_4};$

C. calculating a distance b between the centre of gravity G and the connecting line of axes of the two front wheels, a calculation formula being:

[00013]$b=\frac{\left(F_3+F_4\right).Math.L}{F_1+F_2+F_3+F_4};$

D. determining the deflection angles and deflection directions of the front wheels of the automobile, the automobile speed at the centre of gravity of the automobile being determined according to the average value of the speed v.sub.1 of the left front wheel and the speed v.sub.2 of the right front wheel of the automobile when an average value of the deflection angles of the left and right front wheels is smaller than 2; calculating the speed at the centre of gravity of the automobile based on the left front wheel and the right front wheel respectively according to a steering state of the automobile when the average value of the deflection angles of the left and right front wheels is greater than or equal to 2;
E. calculating a speed v.sub.G1 at the centre of gravity of the automobile based on the left front wheel: [0027] {circle around (1)}. calculating a distance r.sub.1 between the left front wheel and an instantaneous centre O, a calculation formula being:

[00014]$r_1=\frac{L}{\sin .Math..Math.\left({}_1\right)};$ [0028] {circle around (2)}. calculating an angle .sub.G of the centre of gravity formed among the centre of gravity G of the automobile, the instantaneous centre O, and a shaft axis of the rear wheel, a calculation formula being:

[00015]${}_G={\tan }^{-1}\left(\frac{L-b}{r_1.Math.\cos .Math..Math.\left({}_1\right)+i.Math.\left(B-a\right)}\right),$

wherein when the automobile turns left, i=1, and when the automobile turns right, i=1; [0029] {circle around (3)}. calculating a distance r.sub.G between the instantaneous centre O and the centre of gravity G, a calculation formula being:

[00016]$r_G=\frac{L-b}{\sin .Math..Math.\left({}_G\right)};$

and [0030] {circle around (4)}. calculating the speed v.sub.G1 at the centre of gravity of the automobile, a calculation formula being:

[00017]$v_{G.Math..Math.1}=\frac{v_1}{r_1}.Math.r_G;$

F. calculating a speed v.sub.G2 at the centre of gravity of the automobile based on the right front wheel: [0031] {circle around (1)}. calculating a distance r.sub.2 between the right front wheel and the instantaneous centre O, wherein a calculation formula being:

[00018]$r_2=\frac{L}{\sin .Math..Math.\left({}_2\right)};$ [0032] {circle around (2)}. calculating an angle .sub.G of the centre of gravity formed among the centre of gravity G of the automobile, the instantaneous centre O, and a shaft axis of the rear wheel, a calculation formula being:

[00019]${}_G={\tan }^{-1}\left(\frac{L-b}{r_2.Math.\cos \left({}_2\right)-i.Math.a}\right),$

wherein when the automobile turns left, i=1, and when the automobile turns right, i=1; [0033] {circle around (3)}. calculating a distance r.sub.G between the instantaneous centre O and the centre of gravity G, a calculation formula being:

[00020]$r_G=\frac{L-b}{\sin \left({}_G\right)};$

and [0034] {circle around (4)}. calculating the speed v.sub.G2 at the centre of gravity of the automobile, a calculation formula being:

[00021]$v_{G.Math..Math.2}=\frac{v_2}{r_2}.Math.r_G;$

and
G. calculating an average automobile speed v.sub.G at the centre of gravity of the automobile during steering, which is:

[00022]$v_G=\frac{v_{G.Math..Math.1}+v_{G.Math..Math.2}}{2}.$

[0035] According to an automobile speed control method based on the automobile speed measurement above, when the automobile speed is v.sub.G8 m/s, a ratio K of a maximum gravity value to a minimum gravity value in the four gravity sensors is calculated, wherein K=F.sub.max/F.sub.min, and when K10, an automobile speed controller controls the automobile to slow down, so that the ratio K of the maximum gravity value to the minimum gravity value detected by the four gravity sensors is smaller than 5.

Embodiment 2

[0036] In the embodiment 2, the automobile speed measurement and control system further includes an alarm 5 (refer to FIG. 2), wherein the alarm is connected to the automobile speed controller, the alarm includes a sound alarm and/or a light alarm, the sound alarm is mounted in a driving cab, and the light alarm is mounted on an instrument panel.

[0037] In the embodiment 2, when the automobile speed is v.sub.G8 m/s, a ratio K of a maximum gravity value to a minimum gravity value in the four gravity sensors is calculated, wherein K=F.sub.max/F.sub.min, and when 10>K5 or |v.sub.G1v.sub.G2|/v.sub.G0.1, the automobile speed controller alarms through an alarm, and the following steps are the same as that in the embodiment 1.

[0038] By measuring the speeds and deflection angles of the two front wheels in real time, and according to the values of the four gravity sensors, and the axle base L and the wheel base B of the automobile, the centre of gravity G of the automobile is determined by the present invention; and the moving speeds of the left and right front wheels of the automobile around the instantaneous centre O during cornering are converted into the moving speeds at the centre of gravity of the automobile respectively. The left front wheel and the right front wheel are calculated separately in the present invention, and the average value of the two automobile speeds at the centre of gravity of the automobile is used as the actual driving speed of the automobile during cornering, so as to have a higher accuracy. Compared with the method of directly converting the rotational speed of the gearbox output shaft into the automobile speed in the prior art, the automobile speed measured by the present invention during cornering has a higher accuracy, and data with a higher accuracy may be provided for modern intelligent automobiles or automatic automobiles, so as to implement more effective and effective control and ensure the driving safety.

[0039] In addition to the embodiments above, the technical characteristics or technical data of the invention may be re-selected and re-combined within the range disclosed by the claims and the description of the invention, so as to form new embodiments. These embodiments that are not described in details in the invention may be easily implemented by those skilled in the art without going through any creative works. Therefore, these embodiments that are not described in details shall also be deemed as the specific embodiments of the invention and fall within the protection range of the invention.