The present application relates to the technical field of vehicle
steering control, and particularly relates to a rack force fusion
estimation method for different working conditions of steer-by-wire based on fuzzy control, which comprises the following steps: collecting
road roughness, judging whether it is not less than a first threshold value, if yes, measuring a first rack force based on a rack force estimator of a vehicle-tire model, otherwise collecting an actual vehicle speed; judging whether the vehicle speed is less than a second threshold value, if yes, measuring a second rack force based on a rack force estimator of a
steering system model, otherwise judging whether the vehicle speed is less than a third threshold value, if yes, measuring the first rack force, otherwise measuring a front wheel
steering angle of the vehicle, and judging whether it is not greater than a fourth threshold value, if yes, measuring the first rack force, otherwise measuring the second rack force; adopting fuzzy control when the first and second rack forces are converted, so as to realize smooth connection of the rack force
estimation value under different working conditions. Thus, the problem that the applicability of the rack force estimator under bumping road, different vehicle speeds and steering angles is not fully studied in the steer-by-wire
system is solved.