Estimated vehicle body speed calculating apparatus
First Claim
1. An estimated vehicle body speed calculating apparatus for calculating for each control cycle, an estimated vehicle body speed of a vehicle, comprising:
- means for respectively detecting a turning speed of each vehicle wheel;
means for calculating for each control cycle, a vehicle wheel speed and a vehicle wheel speed reduction of each vehicle wheel in accordance with the detected turning speed;
wheel cylinder fluid pressure detecting means for detecting a wheel cylinder fluid pressure of said each vehicle wheel;
limit speed reduction setting means for setting a limit value of the vehicle wheel reduced speed based on the wheel cylinder fluid pressure detected;
estimated vehicle body speed calculating means for calculating the estimated vehicle body speed, wherein the estimated vehicle body speed is set to the vehicle wheel speed calculated for each control cycle in which the vehicle wheel reduced speed is smaller than the limit reduced speed, and wherein the estimated vehicle body speed is set to the value of the estimated vehicle body speed for the previous control cycle added to the limit reduced speed for each control cycle in which the vehicle wheel reduced speed is larger than the limit reduced speed;
means for detecting lock indications of said each vehicle wheel;
means for effecting antilock brake controlling operation when the lock indications are detected; and
memory means for retaining the wheel cylinder fluid pressure at a time when the locking indications are detected, wherein said limit speed reduction setting means sets the limit value of the reduced speed in accordance with a larger value obtained from a comparison of the wheel cylinder fluid pressure retained in said memory means and the fluid pressure detected by said wheel cylinder fluid pressure detecting means.
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Abstract
The apparatus is composed of calculation of a vehicle wheel speed of each vehicle wheel for each of control cycles, calculation of tolerance maximum reduced speed amount approximately proportional to the μ value of the road surface by a wheel cylinder fluid pressure, judgement as to whether the vehicle wheel speed at this time is reduced in speed larger than the estimated vehicle body speed at the last time in the tolerance maximum reduced speed amount at the reduced speed time. When the reduced speed is much larger, a value reduced in the tolerance maximum reduced speed amount from the estimated vehicle body speed at the last time is made an estimated vehicle body speed at this time. On the other hand, when the reduced speed is much smaller, the vehicle wheel speed at this time is made an estimated vehicle body speed at this time.
24 Citations
6 Claims
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1. An estimated vehicle body speed calculating apparatus for calculating for each control cycle, an estimated vehicle body speed of a vehicle, comprising:
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means for respectively detecting a turning speed of each vehicle wheel; means for calculating for each control cycle, a vehicle wheel speed and a vehicle wheel speed reduction of each vehicle wheel in accordance with the detected turning speed; wheel cylinder fluid pressure detecting means for detecting a wheel cylinder fluid pressure of said each vehicle wheel; limit speed reduction setting means for setting a limit value of the vehicle wheel reduced speed based on the wheel cylinder fluid pressure detected; estimated vehicle body speed calculating means for calculating the estimated vehicle body speed, wherein the estimated vehicle body speed is set to the vehicle wheel speed calculated for each control cycle in which the vehicle wheel reduced speed is smaller than the limit reduced speed, and wherein the estimated vehicle body speed is set to the value of the estimated vehicle body speed for the previous control cycle added to the limit reduced speed for each control cycle in which the vehicle wheel reduced speed is larger than the limit reduced speed; means for detecting lock indications of said each vehicle wheel; means for effecting antilock brake controlling operation when the lock indications are detected; and memory means for retaining the wheel cylinder fluid pressure at a time when the locking indications are detected, wherein said limit speed reduction setting means sets the limit value of the reduced speed in accordance with a larger value obtained from a comparison of the wheel cylinder fluid pressure retained in said memory means and the fluid pressure detected by said wheel cylinder fluid pressure detecting means. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification