Providing accurate position with magnetic field measurement
Vehicle technology has evolved from the previous Electro-Hydraulic Power Assisted Steering Mechanism (EHPS) to the Electronic Powered Assisted Steering (EPS) system currently widely used in vehicles. Because EPS has no continuously operating hydraulic pump components, and only when auxiliary power is needed With power output, EPS is more fuel-efficient than EHPS, and it also significantly improves its operating efficiency.
The electronic power assisted steering system consists of electronic control unit, brushless motor, speed reducer, steering shaft, torsion bar, torque sensor and other components. The torque sensing element is responsible for controlling the torsion angle of the steering wheel to change the output assist force of the motor. The accuracy of the operation frequency and the torsion angle of the steering wheel determines one of the important factors for the driver to control the feel of the vehicle.
The torque sensing element is mounted in the steering system and uses the detected rotation angle to cause a time-varying alternating magnetic field. The cut magnetic force lines are guided to the magnetic collection element, and then generated by induction of the linear Hall element IC to generate Huo. The voltage, which is the basic operating principle of the torque sensor. The output Hall voltage and the torque of the steering wheel should be in a linear proportional relationship. When the torque is applied to the steering wheel, the operating angle of the steering wheel is also known. These analog signals are input to the MCU for back-end signal processing, and the motor is further started to achieve an assisted steering effect.