Parking trajectory characteristics were analyzed, and a new trajectory function was proposed based on the known trajectory functions. It was proved that the new function was feasible for trajectory planning by parking trajectory fitting comparison. Potential collision points were analyzed and constraint equations were established accordingly. The orientation constraints at the start point, the location constraint at the parking point and the restriction of vehicle were considered, and the constraint equations were established respectively. Parking trajectory optimization function was presented to minimize the vehicle orientation angle at the parking point with restrictions mentioned above. The approach was used by trajectory planning for general parking space and tight parking space, and the trajectory function was solved using Matlab software. The simulation results show that the car can reverse into parking set safely in general parking space, with the continuously trajectory curvature and the car paralleled with the parking set at the parking point. This approach fails to make the car paralleled with the parking set in tight parking space, but the car can move into parking set safely with the continuous trajectory curvature. It is proved that the approach proposed can find a collision-free path in different parking spaces and meet the demand of continuous trajectory curvature, so the problem of shutting down to steer the wheel in parking process is solved.%分析泊车轨迹曲线特点,在已有轨迹函数基础上提出新的轨迹函数,通过对实际泊车轨迹的拟合证明该函数的可用性.分析泊车环境中存在的可能碰撞点,建立相应的避撞约束函数.以泊车环境障碍约束、车辆自身参数约束、泊车初始点方位约束、泊车终点位置约束为轨迹函数的约束函数,以泊车终点车辆与车位夹角最小为目标函数建立单目标多约束轨迹方程.分别对一般泊车环境和狭小空间泊车环境进行泊车轨迹规划,利用Matlab软件非线性约束优化函数求得轨迹函数参数.仿真结果表明:对于一般泊车环境,该方法能满足泊车轨迹曲率连续性,使车辆无碰撞进入车位,并使车辆与车位平行；对于狭小空间泊车环境,虽未能使车辆与车位平行,但实现了车辆无碰撞地泊车入位并保证轨迹曲率的连续性.由此可知该方法可实现车辆无碰撞地泊车入位,并满足轨迹曲率连续性要求,有效地解决了泊车过程中停车转向问题.
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