Process for assisting downhill driving and associated device
First Claim
1. Process for assisting driving of a vehicle engaged on a slope, the said vehicle including:
- a braking system uncoupled from the operation of a brake pedal by the driver of the vehicle and able to apply a braking torque to at least one wheel of the said vehicle;
at least one wheel velocity sensor (5) able to measure an instantaneous velocity of a wheel of the said vehicle;
the process including the steps consisting of;
determining the instantaneous value of the slope on which the said vehicle is located;
testing the initial simultaneous existence of initial conditions including at least one entry condition; and
, once the said initial conditions are all verified and while at least one exit condition (175-178;
375-377, 380) is not verified, performing successive iterations of a main loop (100, 300) for determination of a target braking torque (Γ
c) consisting of;
defining a desirable velocity (V0) having to be attained by the vehicle;
determining the said target braking torque (Γ
c) as a function of a difference (Δ
V) between the instantaneous value of the said desirable velocity (V0) and the instantaneous value of a calculated velocity (Vc), calculated from measurements performed by the said at least one wheel sensor (5); and
,transmitting (163, 363) a signal corresponding to the value of the said target braking torque (Γ
c) to a braking control system forming part of the braking system;
characterised by the fact that the said initial conditions include an entry condition verified when the vehicle is stationary (52, 252) and by the fact that from the moment at which the said initial conditions are all verified and until an exit condition from the initial procedure is verified, the said target braking torque is determined by an initial procedure of progressive release of the brakes (260, 261) comprising the step consisting of temporally reducing the said target braking torque from an initial stationary value, the said exit condition from the initial procedure depending on a comparison between the said target braking torque (Γ
c) and a theoretical braking torque (Γ
th, S0) which is a function of the value of the slope (p) characterized by the fact that the said initial procedure comprises the steps consisting of;
reducing the said target braking torque (Γ
c) until the said calculated velocity (Vc) is greater than a predetermined threshold velocity,increasing the said target braking torque (Γ
c) until the said exit condition from the initial procedure is verified, the said exit condition from the initial procedure being verified when the said target braking torque (Γ
c) is greater than the said theoretical braking torque (So).
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Accused Products
Abstract
The invention relates to a driving assistance method which is intended for use on a slope. According to the invention, the vehicle comprises an accelerometer which can measure a longitudinal acceleration of the vehicle as measured longitudinal acceleration. The inventive method comprises the following steps consisting in: determining the instantaneous value of the slope (p) on which the vehicle is positioned, by calculating an instantaneous longitudinal acceleration from the measurements taken by wheel speed sensors, and, subsequently, comparing the instantaneous longitudinal acceleration with the longitudinal acceleration measured by the accelerometer; determining (156) a theoretical brake torque (Γth) as a function of the slope such that the vehicle reaches a desired speed (Vo); correcting (162) the theoretical brake torque value in order to obtain a target brake torque (Γ<SB>C</SB>); and emitting (163) a signal corresponding to the target brake torque in the direction of the brake regulation system.
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Citations
17 Claims
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1. Process for assisting driving of a vehicle engaged on a slope, the said vehicle including:
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a braking system uncoupled from the operation of a brake pedal by the driver of the vehicle and able to apply a braking torque to at least one wheel of the said vehicle; at least one wheel velocity sensor (5) able to measure an instantaneous velocity of a wheel of the said vehicle; the process including the steps consisting of; determining the instantaneous value of the slope on which the said vehicle is located; testing the initial simultaneous existence of initial conditions including at least one entry condition; and
, once the said initial conditions are all verified and while at least one exit condition (175-178;
375-377, 380) is not verified, performing successive iterations of a main loop (100, 300) for determination of a target braking torque (Γ
c) consisting of;defining a desirable velocity (V0) having to be attained by the vehicle; determining the said target braking torque (Γ
c) as a function of a difference (Δ
V) between the instantaneous value of the said desirable velocity (V0) and the instantaneous value of a calculated velocity (Vc), calculated from measurements performed by the said at least one wheel sensor (5); and
,transmitting (163, 363) a signal corresponding to the value of the said target braking torque (Γ
c) to a braking control system forming part of the braking system;characterised by the fact that the said initial conditions include an entry condition verified when the vehicle is stationary (52, 252) and by the fact that from the moment at which the said initial conditions are all verified and until an exit condition from the initial procedure is verified, the said target braking torque is determined by an initial procedure of progressive release of the brakes (260, 261) comprising the step consisting of temporally reducing the said target braking torque from an initial stationary value, the said exit condition from the initial procedure depending on a comparison between the said target braking torque (Γ
c) and a theoretical braking torque (Γ
th, S0) which is a function of the value of the slope (p) characterized by the fact that the said initial procedure comprises the steps consisting of;reducing the said target braking torque (Γ
c) until the said calculated velocity (Vc) is greater than a predetermined threshold velocity,increasing the said target braking torque (Γ
c) until the said exit condition from the initial procedure is verified, the said exit condition from the initial procedure being verified when the said target braking torque (Γ
c) is greater than the said theoretical braking torque (So).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification