Anti-skid control system for motor vehicle

Claim 2

An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, which occur in anti-skid cycles, said anti-skid control system comprising: first valve means for alternately building up and holding brake fluid pressure during said brake fluid pressure buildup-control mode; wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal V W responsive to said speed; peak detecting means for receiving said velocity signal V W and for detecting a high peak value V HP and a low peak value V LP of said velocity signal V W when said anti-skid control system is operated; controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal V W has said high peak value V HP to a second time when said velocity signal V W has a value R, said value R corresponding to said velocity signal V W being equal to a reference velocity V WO at the second time, said reference velocity V WO having an initial value at the first time being less than said high peak value V HP by a predetermined velocity value ΔV, having values which vary between the first time and the second time dependent upon a gradient θ, and having a final value equal to said velocity signal V W at the second time corresponding to said value R; acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value V LP by said peak detecting means on the basis of said velocity signal V W between a first value Va and a second value Vb of said velocity signal V W , said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value V LP , said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; and determining means for determining at least one of said predetermined velocity value ΔV, said gradient θ and an initial pressure buildup time T P , for said brake fluid pressure buildup-control mode and in accordance with said measured wheel acceleration.

Claim 3

An anti-skid control system according to claim 1, wherein said predetermined velocity value ΔV, said gradient θ, and said initial pressure buildup time T P are determined in accordance with said measured wheel acceleration in a preceding anti-skid cycle.

Claim 4

An anti-skid control system according to claim 1, wherein said acceleration determining means includes means for calculating a value R O corresponding to said value R of a preceding anti-skid cycle, so that said first value Va and said second value Vb of said velocity signal V W are defined as follows: Va=K.sub.1 ([V.sub.WO ]R.sub.O -V.sub.LP)+V.sub.LP Vb=K.sub.2 ([V.sub.WO ]R.sub.O -V.sub.LP)+V.sub.LP where O<K 1 <K 2 .

Claim 5

An anti-skid control system according to claim 3, wherein K 1 =0.15 and K 2 =0.8.

Claim 6

An anti-skid control system according to claim 1, further comprising selection means for selecting said predetermined velocity value ΔV, said gradient θ, and said initial pressure buildup time T P for an anti-skid cycle in accordance with a value of said measured wheel acceleration.

Claim 7

An anti-skid control system according to claim 1, wherein said acceleration determining means further includes: means for determining said first value V a of said velocity signal V W in accordance with a first predetermined value of velocity of said low peak value V LP ; and means for determining said second value V b of said velocity signal V W in accordance with a second predetermined value of velocity and said low peak value V LP .

Claim 8

An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, each of which occurs in anti-skid cycles, said anti-skid brake control system comprising: first valve means for alternately building-up and holding brake fluid pressure during said brake fluid pressure buildup-control mode; second valve means for reducing brake fluid pressure during said brake fluid pressure reduction mode; wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal V W responsive to said speed; peak detecting means for receiving said velocity signal V W and for determining a high peak value V HP and a low peak value V LP of said velocity signal V W when a wheel is braked; controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal V W has said high peak value V HP to a second time when said velocity signal V W has a value R, said value R corresponding to said velocity signal V W being equal to a reference velocity V WO at the second time, said reference velocity V WO having an initial value at the first time being less than said high peak value V HP by a predetermined velocity value ΔV, having values which vary between the first time and the second time dependent upon a gradient, and having a final value equal to said velocity signal V W at the second time corresponding to said value R; acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value V LP by said peak detecting means on the basis of said velocity signal V W between a first value Va and a second value Vb of said velocity signal V W , said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value V LP , said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; determining means for determining at least one of said predetermined velocity value ΔV, said gradient θ and an initial pressure buildup time T P , for said brake fluid pressure buildup-control mode in accordance with said measured wheel acceleration; and reduction control means for controlling opening of said second valve means during said brake fluid pressure reduction mode, from a time corresponding to an occurrence of said value R until a time corresponding to an occurrence of said low peak value V LP of said velocity signal V W .

Claim 9

An anti-skid control system for a motor vehicle, including a brake fluid pressure buildup-control mode and a brake fluid pressure reduction mode, each of which occurs in anti-skid cycles, said anti-skid brake control system comprising: first valve means for alternately building-up and holding brake fluid pressure during said brake fluid pressure buildup-control mode; second valve means for reducing brake fluid pressure during said brake fluid pressure reduction mode; wheel speed measuring means for measuring a speed of each wheel of the motor vehicle and for providing a wheel velocity signal V W responsive to said speed; peak detecting means for receiving said velocity signal V W and for determining a high peak value V HP and a low peak value V LP of said velocity signal V W when a wheel is braked; controller means for repetitively opening and closing said first valve means during said brake fluid pressure buildup-control mode, from a first time when said velocity signal V W has said high peak value V HP to a second time when said velocity signal V W has a value R, said value R corresponding to said velocity signal V W being equal to a reference velocity V WO at the second time, said reference velocity V WO having an initial value at the first time being less than said high peak value V HP by a predetermined velocity value ΔV, having values which vary between the first time and the second time dependent upon a gradient, and having a final value equal to said velocity signal V W at the second time corresponding to said value R; acceleration measuring means for measuring wheel acceleration during a time after detection of said low peak value V LP by said peak detecting means on the basis of said velocity signal V W between a first value Va and a second value Vb of said velocity signal V W , said first value Va being dependent upon a predetermined rate of wheel velocity and said low peak value V LP , said second value Vb being dependent upon another predetermined rate of wheel velocity and said first value Va; determining means for determining at least one of said predetermined velocity value ΔV, said gradient θ and an initial pressure buildup time T P , for said brake fluid pressure buildup-control mode in accordance with said measured wheel acceleration; and reduction control means for controlling opening of said second valve means during said brake fluid pressure reduction mode, from a time corresponding to an occurrence of said value R until a time corresponding to an occurrence of said low peak value V LP of said velocity signal V W .

Claim 10

An anti-skid control system according to claim 7, wherein said acceleration determining means further includes: means for determining said first value V a of said velocity signal V W in accordance with a first predetermined value of velocity; and means for determining said second value V b of said velocity signal V W in accordance with a second predetermined value of velocity.