Patent ID: 6092882
Filing Date: 2000-07-25
Classification: B60T

Abstract:
A braking force control system of a vehicle, having a front wheel, a rear wheel, a front wheel cylinder for said front wheel, a rear wheel cylinder for said rear wheel and a brake drive apparatus for supplying and controlling a brake pressure to said front wheel cylinder and said rear wheel cylinder, vehicle speed detecting means for detecting a vehicle speed, and steering angle detecting means for detecting a steering angle, comprising:actual yaw rate detecting means for detecting an actual yaw rate;road friction coefficient estimating means for estimating a friction coefficient of a road surface based on said actual yaw rate, said steering angle and said vehicle speed;yaw rate gain calculating means for calculating a yaw rate gain based on said vehicle speed;target yaw rate calculating means for calculating a target yaw rate based on said vehicle speed, said steering angle and said yaw rate gain;target yaw rate restricting means for restricting an absolute value of said target yaw rate to a value below an upper limit value based on said friction coefficient of a road surface and said vehicle speed and for outputting said value as a restricted target yaw rate;yaw rate deviation calculating means for calculating a yaw rate deviation of said actual yaw rate and said restricted target yaw rate;target braking force calculating means for calculating a target braking force based on said yaw rate deviation, said steering angle, said yaw rate gain, said vehicle speed and said actual yaw rate;braking wheel determining means responsive to said actual yaw rate and said yaw rate deviation for selecting an inside rear wheel to be braked when a sign of said yaw rate deviation is different from the sign of said actual yaw rate due to an under-steering operation by a driver, and for selecting an outside front wheel to be braked when the sign of said yaw rate deviation is the same as the sign of said actual yaw rate due to an over-steering operation by said driver, and generating a selection signal;output judging means for selectively determining a judging threshold value based on said yaw rate deviation, said actual yaw rate and said vehicle speed, for outputting a control signal so as to execute a braking force control when an absolute value of said yaw rate deviation is larger than said threshold value and for outputting a noncontrol signal so as to stop a braking force control when said absolute value of said yaw rate deviation is smaller than said threshold value; andbrake signal outputting means responsive to said control signal for outputting a brake signal to said brake drive apparatus so as to apply said target braking force to said braking wheel and responsive to said noncontrol signal for stopping said brake signal to said brake drive apparatus.