Method of controlling slipping or spinning of a vehicle wheel
First Claim
1. A method of controlling slipping or spinning of a wheel of a vehicle, wherein the vehicle hasdriven wheels and non-driven or rolling wheels, anda slip control system for the driven wheels,comprising the steps ofsensing if a respective driven wheel slips or spins above a predetermined slip level, or rotates under conditions indicating a tendency to slip or spin above said predetermined slip level;
- monitoring the speed of at least one of the rolling wheels and deriving rolling wheel output signals representative of said monitored speed;
sensing the speed of at least one driven wheel and deriving driven wheel output signals representative of said sensed speed;
generating a reference parameter signal representative of the speed of the at least one rolling wheel;
comparing the driven wheel output signals with the reference parameter and deriving a comparison signal indicative of slip or incipient slip;
decreasing the speed of rotation of said respective driven wheel when said comparison signal representative of slip indicates wheel slip above said predetermined slip level;
in successive time steps, testing the rolling wheel output signals representative of the speed of the rolling wheel to determine if the signal has a characteristic indicative of change of speed of the rolling wheel which is not physically possible, andif the test indicates a condition of the signal representative of a physically impossible condition,generating, as the comparison signal, a new signal which is representative of at least a lesser change of speed than the rolling wheel output signal representative of said monitored speed.
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Accused Products
Abstract
To prevent slipping or spinning of a driven wheel which, selectively, can be braked or supplied with reduced torque from a vehicle engine, a reference speed is determined against which slipping or tendency to slip is measured. The reference value for slip measuring, derived from non-driven or rolling wheels, is tested for physically impossible conditions and, if such physically impossible conditions obtain, they are disregarded when determining slipping or tendency to slip. Proper speed values can be stored, utilized for subsequent measurement, directly or modified, which may also be made speed dependent, or dependent on differences between the speeds of two rolling wheels.
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Citations
21 Claims
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1. A method of controlling slipping or spinning of a wheel of a vehicle, wherein the vehicle has
driven wheels and non-driven or rolling wheels, and a slip control system for the driven wheels, comprising the steps of sensing if a respective driven wheel slips or spins above a predetermined slip level, or rotates under conditions indicating a tendency to slip or spin above said predetermined slip level; -
monitoring the speed of at least one of the rolling wheels and deriving rolling wheel output signals representative of said monitored speed; sensing the speed of at least one driven wheel and deriving driven wheel output signals representative of said sensed speed; generating a reference parameter signal representative of the speed of the at least one rolling wheel; comparing the driven wheel output signals with the reference parameter and deriving a comparison signal indicative of slip or incipient slip; decreasing the speed of rotation of said respective driven wheel when said comparison signal representative of slip indicates wheel slip above said predetermined slip level; in successive time steps, testing the rolling wheel output signals representative of the speed of the rolling wheel to determine if the signal has a characteristic indicative of change of speed of the rolling wheel which is not physically possible, and if the test indicates a condition of the signal representative of a physically impossible condition, generating, as the comparison signal, a new signal which is representative of at least a lesser change of speed than the rolling wheel output signal representative of said monitored speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. Method of controlling slipping or spinning of a wheel of a vehicle, wherein the vehicle has driven wheels and non-driven or rolling wheels,
and a slip control system for the driven wheels, sensing if a respective driven wheel slips or spins, or rotates under conditions indicating a tendency to slip or spin; -
monitoring the speed of at least one of the rolling wheels and deriving an output signal representative of said monitored speed; and decreasing the speed of rotation of said respective driven wheel, including comparing the speed of at least one of the driven wheels and a reference parameter which includes a value representative of the speed of at least one of the rolling wheels, and deriving a comparison signal, comprising, in accordance with the invention, the steps of approximating the reference speed to a theoretical vehicle speed condition, in decreasing direction (a) in accordance with a slowly decreasing time function having gradually decreasing slope, and corresponding to only little vehicle deceleration, for a predetermined time duration T, and (b) after said time duration T, in accordance with a maximum negative slope corresponding to vehicle deceleration of about -0.3 g maximum. - View Dependent Claims (21)
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Specification