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

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The sensors 1 and 2 for the non-driven wheels supply signals which correspond to the wheel speed to the average former 3 which generates a reference value V.
sub.
F that corresponds to the vehicle speed.
The sensors 4 and 5 of the driven wheels provide wheel speed signals V.
sub.
R to blocks 6 and 7 to which the reference value V.
sub.
F is also supplied.
The signals V.
sub.
R are compared to V.
sub.
F in the blocks and control signals are generated when the wheel speed V.
sub.
R exceeds the reference speed V.
sub.
F by a threshold value .
lambda.
.
This value .
lambda.
is defined by the following relation.
##EQU1## where FP is the pedal position provided by the operator.
It can vary between 0 and 1, a can range between 0.
01 and 0.
04, e.
g.
0.
03, b can range between 0.
5 and 10 km/h, e.
g.
1 km/h, c can range between 0.
5.
times.
10.
sup.
4 and 5.
times.
10.
sup.
4 km/h, e.
g.
1.
times.
10.
sup.
4 km/h, d can range between 0 and 4 g e.
g.
0.
2 g and e can range between 0.
1/sec and 1.
0/sec, e.
g.
0.
3/sec.
The first factor a V.
sub.
F is formed in blocks 6 and 7 and the second factor represented by addend b is supplied to terminals 8 and 9.
The third factor represented by the expression ##EQU2## is formed in a differentiating and substracting block 10 and the fourth factor represented by the expression ##EQU3## is formed in a block 11.
The signal FP representing the position of the accelerator pedal is provided by a pedal position sensor 16.
If the wheel speed value V.
sub.
R exceeds the reference speed value V.
sub.
F by the above indicated threshold value .
lambda.
, however variable, a control signal is generated in blocks 6 and 7 and the corresponding brakes 13 or 14 are operated, for example, by applying pressure through control devices 17 or 18.
If blocks 6 and 7 both supply a control signal, the engine torque is reduced at block 15.