In order to improve the control of the vehicle safety

starting from the improvement of steering system

by using harmonic gear as the core component of the active steering system

the function of changing steering gear ratio is realized.According to the structure principle of the active steering system

the relevant mathematical model is established

the motor voltage control method and PID control method are used to control the system.The whole simulation model is established for the simulation research in simulink.Results show that the vehicle steering response faster at low speed and response slower at high speed

the flexible and convenient at low speed and stability at high speed for steering is implemented.