Research On Design And Performance Of Magnetorheological Brake

As a kind of smart material,magnetorheological fluid can quickly and repeatedly changing its damping characteristics that it has been widely used in engineering field.Magnetorheological brakes are characterized by their smooth braking process,stable performance,fast response,can effectively integration with the control-by-wire system.It has been widely applied in medical rehabilitation training equipment,vehicle brake and other aspects.A comprehensive analysis of the advantages of existing magneto-rheological brakes,such as disc,drum,and multi-pole type,propose a new configuration that takes into account the advantage of disc and drum structures.According to the characteristics of pure shearing of magnetorheological fluid,a Bingham model was used to establish a theoretical model of magnetorheological brake braking torque,and the four main factors affecting the braking torque were analyzed.The leavers of each factor were determined by combining domestic and foreign research results and related theories.Based on the Taguchi optimization algorithm,L₁₆（4⁴）orthogonal tables are determined and 16 simulation structures are obtained.Maxwell analysis software was used to simulate the electromagnetic field of the magneto-rheological brake structure,the magnetic field strength of magnetized magnetic fluid is extracted and the braking torque of the magneto-rheological brake is calculated.Using the goal function that bigger is better calculating signal-to-noise ratio of the braking torque and coil power consumption,analysis the factor signal-to-noise and effect weight.The current and stator inner diameter have the greatest influence on the braking performance.Determine the four factor optimal result that each lever signal-to-noise bigger is the best.According the Maxwell function,material strength need to meet the structure require,assembly characteristics,good economical in manufacture to determine the final dimensions of magnetorheological brakes,drawing the parts drawing.An experimental test platform was set up to test the static and dynamic performance of the magneto-rheological fluid brake device.It was verified that the designed structure was effective,and the experimental results reached the expected goals.A mathematic model of the magneto-rheological brake about speed and current was established.By correcting the empirical formula ofτ-H,the error between the theoretical calculation and the measured value is obviously reduced,and the correction coefficient gradually decreases with the increase of the rotating speed,which proves that the shear thickness will occur when the magnetorheological fluid is sheared at high speed.According to the different rotation speeds,it is feasible to use the Bingham model for theoretical analysis after using the corresponding correction coefficients.