Research On Steering Control Algorithm For Automatic Vertical Parking

Automatic Parking System has greatly reduced fatigue of drivers and traffic crashes caused of parking,which improve the safety and easiness of driving. Automatic Parking System is becoming more and more important as one of intelligent Automotive technologies. Automatic Parking System covers vertical parking, parallel parking and diagonal parking.One of the central parts of Automatic Parking System is about the control of steering.A research on steering control algorithm on vertical parking system is underway.The contexts such that is as follows:In Chapter One, it introduces the developing background and significance of research on automatic parking system,the component and application of this system and the present research status of steering control algorithm in Automatic Parking System. In the end the main content of this paper is showed.In Chapter Two,firstly,the size of parking lot is fixed according to the practical situation of parking.Then a automotive kinematics model is built taking the kinematics and steering performance of low speed.A simulation setting is established for the rearch on steering control algorith.The main content of Chapter Three is the research on steering control algorithm on vertical parking system according to different start positon.To simplify the research,the original heading angle is premised to be zero.A situation of the parking lot right to the vehicle to be parked is considered.Different steering control maneuver is applied according to different start area in the light of parking experience and the theory of J.A.REEDS and L.A.SHEPP.According to the analysis of the crash constraint,the parking area is divided into area in which the vehicle can be parked with the maximum steering angle, some steering angle less than the maximum and the gear has to be shifted. As for the situation where the gear has to be shifted,firstly the steering wheel is turning right with the maximum angle and back motion is adopted. Then,the steering wheel is turning left with the maximum angle and forward motion is adopted when the vehicle is about to hit the boudary of the ajacent vehicles.To some point, the steering wheel is turning right with the maximum angle and back motion is adopted until the vehicle is parallel to the ajacent vehicle.The four time spans are obtained throuth geometry deduction,which are the important parameters of the steering control algorithm.At last,a simulation is carried out,which can park the vehicle successfully.The main aim of Chapter Four is to optimize the steering control using genetic algorithm aiming at the steering control with gear shift.Penalty function is adopted to improve the design of that in Chapter 3.Besides,a control object that the length of the travel is the smallest is added.The optimized results with genetic algorithm can make the car park sucessfully ,which make the length of travel smaller in comparison with the unoptimized ones.The Chapter Five is aim to validate the model using a more accurate vehicle dynamic simulatin software VEDYNA. The steering control algorithm according to different start area is validated using VEDYNA.The simulation results with VEDYNA match those of the kinematics model.This verifies the feasibility of this research. The Chapter Six smmarize the contents of the research in the article and further work are stated.