EP0522615A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Vehicle handling control method during antilock braking
Assignee: Motors Liquidation Co
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Filing: 1992-06-11
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Granted: —
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Expires: 2012-06-11
Abstract
Abstract An algorithm is provided for improved lateral force during cornering while in antilock braking mode. For each wheel, the peak slip value at which maximum adhesion between tyre and road occurs is determined, and the peak value is reduced by offsets (or factors) to increase lateral force according to the cornering manoeuvre in progress to derive a target slip value. A cornering offset and an evasive offset are functions of steering wheel angle and steering wheel rotation rate, respectively, and of vehicle deceleration. When slip is determined using average vehicle speed, a geometry correction term which is a function of steering angle, vehicle speed and deceleration is added to the target value. The offsets and the correction term have different values for inside and outside wheels.
Inventors
- 👤 Yuen-Kwok Chin
- 👤 William Chin-Woei Lin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 03:24
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/1755; B60T2201/00; B60T2201/16; Y; Y10; Y10S; Y10S303/00; Y10S303/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
144 words
A method of enhancing cornering ability during antilock brake operation in a vehicle having an antilock brake system comprising the steps of measuring (21) vehicle deceleration; and determining (38) the wheel slip of each wheel; characterised by the steps of sensing (23) the amount of steering wheel rotation and calculating the rate of rotation; calculating (98) for each wheel the peak slip value which can generate the highest amount of surface adhesion; calculating (54, Figure 3) a cornering term for each wheel as a function of steering wheel rotation; calculating (58, Figure 3) an evasive term as a function of the rate of steering wheel rotation and vehicle deceleration; calculating (100) a target slip value of each wheel as a function of the evasive term, the cornering term and the peak slip value; and regulating (16,4) each wheel to the respective target slip value.
Claim 2
Dependent Claim
114 words
A method as claimed in claim 1, wherein the step of determining the slip of each wheel comprises measuring (10) each wheel speed; estimating vehicle speed during braking; estimating each wheel slip from wheel speed and estimated vehicle speed; compensating each estimated wheel slip by inside and outside geometry correction terms which account for the difference in wheel speed of wheels inside and outside of the path of travel and which terms are a function of steering wheel rotation and vehicle speed and acceleration, wherein the estimated slip of the inside wheels is decreased by the inside correction term and the estimated slip of the outside wheels is increased by the outside correction term.
Claim 3
Dependent Claim
112 words
A method as claimed in claim 2, wherein the step of compensating each wheel slip comprises providing for inside and outside wheels separate tables of geometry parameters addressed by the amount of steering wheel rotation; establishing empirical values for deceleration correction as a function of vehicle deceleration; establishing empirical values for speed correction as a function of vehicle speed; determining the inside and outside geometry parameters, the deceleration correction value and speed correction value for current steering wheel rotation, vehicle deceleration correction, and vehicle speed; calculating the geometry correction terms as the products of the current values of the respective geometry parameters, and the deceleration correction value, and vehicle speed correction value.
Claim 4
Independent Claim
144 words
A method of enhancing cornering ability during antilock brake operation n a vehicle having an antilock brake system comprising the steps of measuring (21) vehicle deceleration; and determining (38) the wheel slip of each wheel; characterised by the steps of sensing (23) the amount of steering wheel rotation and calculating the rate of rotation; calculating (98) for each wheel the peak slip value which can generate the highest amount of surface adhesion; calculating (54, Figure 3) a cornering offset for each wheel as a function of steering wheel rotation; calculating (58, Figure 3) an evasive offset as a function of the rate of steering wheel rotation and vehicle deceleration; calculating (100) a target slip value of each wheel as the sum of the evasive offset, the cornering offset and the peak slip value; and regulating (16,4) each wheel to the respective target slip value.
Claim 5
Dependent Claim
77 words
A method as claimed in claim 4, wherein the step of calculating an evasive offset comprises establishing empirical parameters for evasive correction as a function of the rate of steering wheel rotation; establishing empirical values for deceleration correction as a function of vehicle deceleration; determining the evasive correction parameter and deceleration correction value for current steering wheel rate and vehicle deceleration; and calculating the evasive offset by multiplying the evasive correction parameter by the deceleration correction value.
Claim 6
Dependent Claim
37 words
A method as claimed in claim 5, wherein the absolute value of the evasive correction parameter is zero below a steering wheel rotation rate threshold and gradually increases to a maximum value at rates above the threshold.
Claim 7
Dependent Claim
48 words
A method as claimed in claim 5, wherein wheels outside the vehicle path have an evasive offset larger than wheels inside the path, and wherein a calculated evasive offset for an outside wheel is reduced by a constant factor to obtain an evasive offset for an inside wheel.
Claim 8
Dependent Claim
30 words
A method as claimed in claim 6, wherein the deceleration correction parameter is a value less than unity at zero deceleration and gradually increases to unity at larger deceleration values.
Claim 9
Independent Claim
78 words
A method as claimed in any one of claims 4 to 8, wherein the step of calculating a cornering offset term comprises establishing empirical parameters for cornering correction as a function of the steering wheel rotation; establishing empirical values for deceleration correction as a function of vehicle deceleration; determining the cornering parameter and deceleration correction values for current steering wheel rotation and vehicle deceleration; and calculating the cornering offset by multiplying the cornering parameter by the deceleration correction.
Claim 10
Dependent Claim
47 words
A method as claimed in claim 9, wherein wheels outside the vehicle path have a cornering offset larger than wheels inside the path, and wherein a calculated offset for an outside wheel is reduced by a constant factor to obtain a cornering offset for an inside wheel.
Claim 11
Independent Claim
148 words
A method of enhancing cornering ability during antilock brake operation in a vehicle having an antilock brake system comprising the steps of measuring (21) vehicle deceleration; and determining (38) the wheel slip of each wheel; characterised by the steps of sensing (23) the amount of steering wheel rotation and calculating the rate of rotation; calculating (98) for each wheel the peak slip value which can generate the highest amount of surface adhesion; calculating (54, Figure 3) a cornering reduction ratio for each wheel as a function of steering wheel rotation; calculating (58, Figure 3) an evasive reduction ratio as a function of the rate of steering wheel rotation and vehicle deceleration; calculating (100) a target slip value of each wheel as the product of the evasive reduction ration, the cornering reduction ratio and the peak slip value; and regulating (16,4) each wheel to the respective target slip value.
Claim 12
Dependent Claim
86 words
A method as claimed in claim 11, wherein the step of calculating an evasive reduction ratio comprises establishing empirical parameters with values ranging from zero to unity for evasive correction as a function of the rate of steering wheel rotation; establishing empirical values for deceleration correction as a function of vehicle deceleration; determining the evasive correction parameter and deceleration correction value for current steering wheel rate and vehicle deceleration; and calculating the evasive reduction ratio by multiplying the evasive correction parameter by the deceleration correction value.
Claim 13
Dependent Claim
51 words
A method as claimed in claim 12, wherein wheels outside the vehicle path have an evasive reduction ratio smaller than wheels inside the path, and wherein a calculated evasive reduction ratio for an outside wheel is reduced by a constant factor to obtain an evasive reduction ratio for an inside wheel.
Claim 14
Independent Claim
85 words
A method as claimed in any one of claims 11 to 13, wherein the step of calculating a cornering reduction ratio term comprises establishing empirical parameters ranging from zero to unity for cornering correction as a function of the steering wheel rotation; establishing empirical values for deceleration correction as a function of vehicle deceleration; determining the cornering parameter and deceleration correction values for current steering wheel rotation and vehicle deceleration; and calculating the cornering reduction ratio by multiplying the cornering parameter by the deceleration correction.
Claim 15
Dependent Claim
51 words
A method as claimed in claim 14, wherein wheels outside the vehicle path have a cornering reduction ratio smaller than wheels inside the path, and wherein a calculated cornering reduction ratio for an outside wheel is reduced by a constant factor to obtain a cornering reduction ratio for an inside wheel.
References Cited (Backward Citations)
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