Nonlinear ABS control method based on fractional order extremum search

Abstract

The invention discloses a nonlinear ABS control method based on fractional order extremum search. The nonlinear ABS control method mainly comprises the steps that an automobile dynamics model, a tiremodel and a reference slip rate model are established respectively; designing a nonlinear ABS controller and designing a fractional order extremum search controller; setting a filter and integral feedback in extreme value search control to be a fractional calculus algorithm, braking deceleration serves as output of the search control, a fractional coefficient optimization function with the brakingdeceleration as an index is established, the fractional coefficient capable of enabling the fractional coefficient optimization function to be maximum is optimized, and determining the optimal fractional coefficient. The method has the beneficial effects that the advantages of robustness and stability of a fractional order system can be converted into an extreme value search controller to be matched with nonlinear control, the response characteristic of a braking system can be improved, the braking deceleration of a vehicle is increased, and the braking distance is reduced.

Description

technical field [0001] The invention relates to a control method of an automobile anti-lock braking system, in particular to a nonlinear ABS control method based on fractional extreme value search, and belongs to the field of automobile braking systems. Background technique [0002] Anti-lock brake system (antilock brake system) referred to as ABS. The function is to automatically control the braking force of the brake when the car is braking, so that the wheel is not locked and is in a state of rolling and sliding (slip rate is about 20%), so as to ensure that the adhesion between the wheel and the ground is at the maximum. . [0003] However, the optimal slip ratio of different road surfaces is different. At present, most of the braking force control systems used by vehicles adopt threshold-based road surface recognition methods, which can only obtain rough classification of road surface adhesion. Although this identification method is simple and effective, the estimati...

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Problems solved by technology

Although this identification method is simple and effective, the estimation result is rough, and there are large uncertainties and errors. The braking force control strategy designed according to the road surface identification method cannot make full use of the ground adhesion, so that the braking performance of the vehicle is limited. reduced by

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