Study On The Structure And Performance Of Magneto-rheological Brake

Magneto-rheological fluid(MRF)is a new type of intelligent material.With the change of the external magnetic field,the MRF has rapid,continuous,reversible and variable rheological properties.Based on the rheological properties above,researchers had designed a variety of mechanical devices,which are widely used in all fields.The Magneto-rheological brake(MRB)designed based on its cutting mode can produce fast,continuous,non-pulsating and reversible braking torque.The traditional hydraulic brake system makes the car fluctuating when the braking happens due to their structural characteristic,and its parts increases the weight of the car,which greatly increases the car's useless.The antilock braking system(ABS)on the basis of it makes the car more complex,which leads to ever-greater probability of car accidents.Due to its advantages such as simple structure and single control parameters,MRB has broad prospects and has a potential to replace the traditional hydraulic brake system.It can simplify the structure of car and has broad prospects for development greatly.However,the research on MRB is still in the initial stage of development.It is of great significance to study the performance of MRB and its controller.The main contents of this paper are as follows:(1)By consulting relevant literatures,the current vehicle braking systems were summarized,the deficiencies of the existing automobile brake system was stated,the development and application of magneto-rheological fluid were introduced and the development of MRB was described briefly.(2)To study the influence of working gaps and current to braking time,the mathematical model of braking time was established based on the Bingham plastic model,and the theoretical calculation of braking time under different current and working gaps was carried out based on the model above.The corresponding experimental was carried out by using the MRB with adjustable working gap.(3)The mathematical model of braking torque is built on the MRB both with coil outside and inside the disc under different radius of brake disc,and the corresponding magnetic field simulation and optimization were carried out.The performance of two kinds of brakes was compared,and the respective advantages and disadvantages were analyzed..(4)A disc MRB with coil outside the disc was designed,and electromagnetic simulation of the brake was carried out by using the APDL module in ANSYS software.The brake was further optimized and the brake prototype was processed.The rationality and stability of the MRB was verified based on the test.(5)A magneto-rheological brake controller was designed by using Arduino board and L9349 chip.In order to study the reaction characteristics of MRB,tracking performance tests of the braking torque were carried out with step signal and sine signal law.