Abstract:

 A coordinated lateral and longitudinal control method was developed by using a model predictive control (MPC) to solve the motion control with high nonlinearity and strong coupling for unmanned vehicles. According to the curvature of the reference path, the reference speed profile was determined, and then tracked by a layered longitudinal controller. An upper longitudinal controller was used to calculate the desired acceleration through the MPC, while a lower controller was used to coordinate the driving and braking by an inverse-longitudinal-dynamic-model. A lateral controller was used to predict the changes of the system state based on the kinematic model to solve the vehicle front- wheel steer- angle when taking the current system state and a longitudinal-velocity-prediction-sequence as the inputs. The simulation results show that the root mean square error is 0.086 km/h for longitudinal vehicle speed compared to the reference speed, and is 94 mm for lateral position compared to the reference path. Therefore, this method achieves an effective control of vehicle motion.

Key words: unmanned vehicles , motion control ,  coordinated control , model predictive control (MPC)