Research On 3D Magnetic Torque Sensor Used In EPS

As the growing operation and comfort requirements of the automobile steering system,the Hydraulic Power Steering(HPS)has been increasingly superseded by Electric Power Steering(EPS)in the application of vehicle steering control system.The torque sensor is a crucial factor for Electric Power Steering(EPS)that decides the capability of power-assisted steering.The paper proposes the three-dimensional electromagnetic induction torque sensor designed by Flexible Printed Circuit(FPC)to satisfy the special demands of sensor structure and measure performance in EPS application field.The design of three-dimensional cylinder electromagnetic coupling and surface nesting eddy-current coupling structure realizes the combination of vertical coil and surface coil that effectively reduce the coupling volume and avoids the inner electromagnetic interference.The measuring principle and structure at home and abroad is analyzes the paper,the electromagnetic coupling theory is eplored by using MATLAB software to determine the sensor of the three-dimensional cylindrical structure.The electromagnetic coupling system of the designed sensor is mathematically analyzed,and it is simulated by using Ansoft Maxwell electromagnetic simulation software to access the related parameters of structure and performance of torque sensor,to provide some reference for structure improvement and processing circuit design.The signal processing circuits including exciting coil oscillating circuits and output signal detection circuits,etc.of the sensor are designed and simulated by Multisim circuit simulation software.Statistical-based on the signal output form of processing circuits,the linear signal measuring algorithm is designed and program is written.The FPC circuit board is completed,a prototype is assembled by the design of electromagnetic coupling system and processing circuit.After measuring and calculating,comparing to the same classification.The radial dimension of the torque sensor in the paper is reduced by 50%,and the volume is reduced to 39.6%,that saves the installation space.After basal performance test supplying 5V by EPS,the torque sensor output 0.5 to 4.5V sinusoidal voltage signal,PWM waveform is output through MCU,which can satisfy the measurement needs of EPS controller.