Method for characterising and improving the behaviour of a vehicle

1. A method for characterising a behaviour of a vehicle that includes a body, at least one wheel, and at least one suspension device linking the at least one wheel to the body, the method comprising steps of, for a value of a parameter that when varied modifies a friction generated in the at least one suspension device:

(A) applying a predetermined stress cycle to the at least one suspension device so as to identify a friction present in the at least one suspension device;

(B) determining, for the at least one suspension device, a value of an indicator relating to the friction identified in the predetermined stress cycle;

varying the value of parameter and repeating the steps (A) and (B) so as to obtain a variation of the indicator relating to the friction generated in the at least one suspension device according to the parameter; and

for the at least one suspension device, determining at least one interval of the parameter in which the indicator relating to the friction is greater than a predetermined threshold for the vehicle.

2. The method according to claim 1 , wherein the vehicle includes first and second wheels and first and second suspension devices respectively linking the first and the second wheels to the body.

3. The method according to claim 2 , wherein the first and second wheels form opposite wheels of a same axle of the vehicle.

4. The method according to claim 1 , wherein during the predetermined stress cycle:

the at least one wheel is vertically displaced in a direction substantially parallel to a vertical direction of the at least one wheel, and

for each value of the parameter, a variation of a vertical force exerted on the at least one wheel is measured as a function of a vertical displacement of the at least one wheel.

5. The method according to claim 2 ,

wherein during the predetermined stress cycle:

each of the first and second wheels is vertically displaced in a direction substantially parallel to a vertical direction of the first and second wheels, and

for each value of the parameter, a variation of a vertical force exerted on each of the first and second wheels is measured as a function of a vertical displacement of each of the first and second wheels, and

wherein the first and second wheels are vertically displaced simultaneously in opposite orientations.

6. The method according to claim 4 , wherein, for the at least one suspension device, the value of the indicator relating to the friction is determined from a hysteresis of a cycle of the displacement of the at least one wheel as a function of the force exerted on the at least one wheel in the vertical direction.

7. The method according to claim 1 , wherein the parameter includes a force applied to the at least one wheel in a direction substantially parallel to a transversal direction of the at least one wheel.

8. The method according to claim 7 , wherein the steps (A) and (B) are performed:

for a first value of the parameter, and then

for a second value of the parameter opposite to the first value of the parameter.

9. The method according to claim 1 , wherein the parameter includes an offset value of the at least one wheel.

10. The method according to claim 9 , wherein the steps (A) and (B) are performed:

for a first offset value equal to an initial offset value modified by a first variation, and then

for a second offset value equal to the initial offset value modified by a second variation opposite to the first variation.

11. The method according to claim 1 , wherein the parameter includes an angle of inclination or a steering error angle of the at least one suspension device.

12. The method according to claim 1 ,

wherein the method is performed on a test bench that includes a frame, and

wherein the body is fixed relative to the frame.

13. A method for improving a behaviour of a vehicle, the method comprising steps of:

characterizing a behaviour of the vehicle, which includes a body, at least one wheel, and at least one suspension device linking the at least one wheel to the body, the characterizing step including substeps of, for a value of a parameter that when varied modifies a friction generated in the at least one suspension device:

(A) applying a predetermined stress cycle to the at least one suspension device so as to identify a friction present in the at least one suspension device,

(B) determining, for the at least one suspension device, a value of an indicator relating to the friction identified in the predetermined stress cycle,

varying the value of the parameter and repeating the substeps (A) and (B) so as to obtain a variation of the indicator relating to the friction generated in the at least one suspension device according to the parameter, and

for the at least one suspension device, determining at least one interval of the parameter in which the indicator relating to the friction is greater than a predetermined threshold for the vehicle; and

modifying the vehicle so as to generate friction in the at least one suspension device, such that the indicator relating to the friction of the vehicle after modification is greater than or equal to the predetermined threshold.

14. The method according to claim 13 ,

wherein the at least one wheel includes a disc, a wheel rim, and a tire, and

wherein the modifying step involves a modification to at least one of: the tire, the disc, and the wheel rim of the at least one wheel.

15. The method according to claim 13 ,

wherein the at least one wheel includes a disc, a wheel rim, and a tire, and

wherein the modifying step includes fitting a ring between the wheel rim and the tire.

16. The method according to claim 13 , wherein a geometry of the at least one suspension device is modified according to at least one parameter selected from:

a parallel alignment of the vehicle,

a static rake of the vehicle,

a steering error angle of the at least one suspension device, and

an angle of inclination of the at least one suspension device.

17. The method according to claim 13 ,

wherein the vehicle includes a hub, and

wherein a shim is mounted between the hub and the at least one wheel.