Simulation Study On Brake System Of Straddled Monorail Vehicle

With the new developmental climaxes of the urban rail transit industry in our country,straddled monorail transit has won the favor of many cities because of its distinct feature,and a number of cities are constructing or planning to construct monorail transit.However,good tools are prerequisite to the successful execution of a job.As an important part of monorail vehicle technology,brake system isn't only related to the running stability,but also the basic guarantee of train secure operation.Besides,autonomous driving,precise parking and other new technologies make higher demand for brake system.So this paper focuses on the brake system of monorail vehicle,to further study its brake performance.According to the basic requirements of brake system on the monorail vehicle,and combined with the features of brake system on the monorail vehicle or other urban rail vehicle at home and abroad,this paper design the air and electric blended brake system,which adopts regenerative brake system and computer-controlled electrical direct electro-pneumatic brake with hydraulic caliper system.Based on analyzing the structure,functions and related parameters,the system is divided into regenerative brake unit and air brake unit,and separately analyzed by computer numerical simulation technology.For the regenerative brake part,this paper analyses the theory of coordinate transformation and the mathematical model of three-phase AC asynchronous motor in turn.After in-depth study on asynchronous motor vector control technology based on Space Vector Pulse Width Modulation(SVPWM),the models of regenerative brake system are also built in the AMESim software.For the air brake part,this paper analyses the physical structure and basic principle of computer-controlled electrical direct electro-pneumatic brake system firstly.Then,some important components,such as electro-pneumatic valve,relay valve,empty-load valve,the emergency valve,air-oil conversion device and hydraulic caliper,are built models and analyzed in the AMESim software.On this basis,the complete models of direct electro-pneumatic brake system are built.Finally,by combining the models of brake control system,regenerative brake system and air brake system,the simulation model of the whole train(2Mc+4M)brake system is established.After that,the performance curves are obtained through running the models in service brake and emergency brake,mainly including the brake cylinder pressure,motor torque,the brake distance and the brake deceleration,the brake performance are analyzed as well.Besides,with running the model of brake system under the condition of uphill and downhill grade and air brake power failure,the speed limitation with different operating condition are discussed.