| The scenarios faced by autonomous vehicles at high speed are often complex,such as wet roads,multi-obstacle vehicles,avoiding vehicles and pedestrians emergent.This paper proposes a trajectory planning and tracking control method that considers active safety,which aims at addressing safety issues for pedestrians and vehicles traveling at high speeds in complex scenarios.This method,which is based on the vehicle dynamics model,combines the improved traffic environment potential field model with model predictive control(MPC)to ensure the safety of pedestrians and vehicles.Sequential quadratic programming(SQP)is employed to solve the MPC,and the control quantity that meets the constraints of lateral stability is directly obtained.This method makes trajectory planning and tracking control of autonomous vehicles simultaneously,while also coordinating multiple active safety objectives such as speed maintenance,adaptive following distance,lane-keeping,car-following,lateral stability,emergency braking,and emergency steering.As a result,it effectively addresses safety issues for both vehicles and pedestrians during obstacle avoidance in complex driving scenarios:1)Aiming at the longitudinal safety problems such as rear-end collision of vehicles in complex scenarios,the potential field of obstacle vehicles is designed considering the longitudinal safety distance of vehicles,and the distance can be adjusted adaptively according to the speed of the obstacle vehicles in front,thus ensuring the longitudinal safety of vehicles.2)Aiming at reducing the danger of rollover and skidding of high-speed vehicles in intricate circumstances,the MPC is augmented with lateral stability constraints,such as the cross-load transfer rate of vehicles,thus enhancing their lateral stability.3)Aiming at the sudden situation caused by the illegal driving of the obstacle vehicle ahead,the obstacle potential field we designed will guide the autonomous vehicle to turn when the distance is less than the safe distance,so as to realize the synergy of steering and braking to urgently avoid the illegal obstacle vehicle.4)Aiming at the problem of pedestrian collision avoidance when pedestrians cross the lane in violation of regulations,considering the safe distance between pedestrians and vehicles,a pedestrian potential field is designed,which will guide the autonomous vehicle to slow down and turn to avoid pedestrians when the distance between the pedestrian workshop is approaching or less than the safe distance.5)Aiming at making the vehicle avoid collision in time under sudden circumstances,not only the gradient continuous Gaussian function and quadratic polynomial are used to establish the traffic environment potential field,but also the optimization solution of MPC is carried out by SQP,and the control accuracy and the calculation time of the optimization solution are considered to improve the real-time of vehicle obstacle avoidance. |
