Drive slip regulating system wherein a slippage threshold is determined from the speed and acceleration of non-driven wheels

Claim 2

Drive slip control system for a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said system comprising means for generating wheel speed values representing speeds of the driven wheels, means for determining speeds of the non-driven wheels, means for generating a reference speed value V F from the speeds of the non-driven wheels, means for differentiating V F to form an acceleration value dV F /dt, means for forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor formed by the relation (dV F /dt-d)/e, where d and e are constants, means for generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and means for applying the brake of each driven wheel when a control signal for the respective driven wheel is generated.

Claim 3

Drive slip control system as in claim 1 wherein said means for forming a threshold slippage value λ further adds a fourth factor which depends upon the square of the reference speed V F .

Claim 4

Drive slip control system as in claim 2 further comprising means for determining the position of the accelerator pedal and generating a signal FP representative of said position, said fourth factor being formed by the relation FR (V F ) 2 .

Claim 5

Drive slip control system as in claim 2 further comprising means for determining the position of the accelerator pedal and generating a signal FP representative of said position, said third factor being formed by the relation (dV F /dt-d)FP/e.

Claim 6

Drive slip control system as in claim 1 further comprising means for determining the position of the accelerator pedal and generating a signal FP representative of said position, said third factor being formed by the relation ##EQU4##

Claim 7

Drive slip control system as in claim 1 further comprising means for reducing the engine torque when the differences between the speeds of both driven wheels and the reference speed both exceed the threshold slippage value λ.

Claim 8

Method of controlling drive slippage in a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said method comprising generating wheel speed values representing the speeds of the driven wheels, determining speeds of the non-driven wheels, generating a reference speed value V F from the speeds of the non-driven wheels, differentiating V F to form an acceleration value dV F /dt, forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor formed by the relation (dV F /dt-d)/e, where d and e are constants, generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and applying the brake of each driven wheel when a control signal for said driven wheel is generated.

Claim 9

Method of controlling drive slippage in a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said method comprising generating wheel speed values representing the speeds of the driven wheels, determining speeds of the non-driven wheels, generating a reference speed value V F from the speeds of the non-driven wheels, differentiating V F to form an acceleration value dV F /dt, forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor formed by the relation (dV F /dt-d)/e, where d and e are constants, generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and applying the brake of each driven wheel when a control signal for said driven wheel is generated.

Claim 10

Method as in claim 7 wherein said threshold slippage value λ is formed by further adding a fourth factor which depends on the square of the reference speed V F .

Claim 11

Method as in claim 8 further comprising determining the position of the accelerator pedal, generating a signal FP representative of said position, and forming said fourth factor by the relation FP (V F ) 2 .

Claim 12

Method as in claim 8 further comprising determining the position of the accelerator pedal, generating a signal FP representative of said position, and forming said third factor by the relation (dV F /dt-d)FP/e.

Claim 13

Method as in claim 7 further comprising determining the position of the accelerator pedal, generating a signal FP representative of said position, and forming said third factor by the relation ##EQU5##

Claim 14

Method as in claim 7 wherein the engine torque is reduced when the differences between the speeds of both driven wheels and the reference speed exceed the threshold slippage value λ.

Claim 15

Drive slip control system for a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said system comprising means for generating wheel speed values representing the speeds of the driven wheels, means for determining speeds of the non-driven wheels, means for generating a reference speed value V F from the speeds of the non-driven wheels, means for differentiating V F to form an acceleration value dV F /dt, means for forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor which is dependent upon dV F /dt, and a fourth factor which depends on the square of the reference speed V F , means for generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and means for applying the brake of each driven wheel when a control signal for the respective driven wheel is generated.

Claim 16

Drive slip control system for a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said system comprising means for generating wheel speed values representing the speeds of the driven wheels, means for determining speeds of the non-driven wheels, means for generating a reference speed value V F from the speeds of the non-driven wheels, means for differentiating V F to form an acceleration value dV F /dt, means for forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor which is dependent upon dV F /dt, and a fourth factor which depends on the square of the reference speed V F , means for generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and means for applying the brake of each driven wheel when a control signal for the respective driven wheel is generated.

Claim 17

Drive slip control system as in claim 13 further comprising means for determining the position of the accelerator pedal and generating a signal FP representative of said position, said fourth factor being formed by the relation FR (V F ) 2 .

Claim 18

Drive slip control system as in claim 13 further comprising means for reducing the engine torque when the differences between the speeds of both driven wheels and the reference speed both exceed the threshold slippage value λ.

Claim 19

Method of controlling drive slippage in a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said method comprising generating wheel speed values representing the speeds of the driven wheels, determining speeds of the non-driven wheels, generating a reference speed value V F from the speeds of the non-driven wheels, differentiating V F to form an acceleration value dV F /dt, forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor which is dependent upon dV F /dt, and a fourth factor which depends on the square of the reference speed V F , generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and applying the brake of each driven wheel when a control signal for said driven wheel is generated.

Claim 20

Method of controlling drive slippage in a vehicle having two driven wheels, two non-driven wheels, brakes associated with said wheels, an operator controlled accelerator pedal, and an engine which develops torque, said method comprising generating wheel speed values representing the speeds of the driven wheels, determining speeds of the non-driven wheels, generating a reference speed value V F from the speeds of the non-driven wheels, differentiating V F to form an acceleration value dV F /dt, forming a threshold slippage value λ by adding a first factor which is a fraction of V F , a second factor which is a constant, and a third factor which is dependent upon dV F /dt, and a fourth factor which depends on the square of the reference speed V F , generating a control signal for each driven wheel when the difference between the wheel speed value for the respective driven wheel and the reference speed value exceeds said threshold slippage value λ, and applying the brake of each driven wheel when a control signal for said driven wheel is generated.

Claim 21

Method as in claim 16 further comprising determining the position of the accelerator pedal, generating a signal FP representative of said position, and forming said fourth factor by the relation FP(V F ) 2 .

Claim 22

Method as in claim 16 wherein the engine torque is reduced when the differences between the speeds of both driven wheels and the reference speed exceed the threshold slippage value λ.