Collision avoidance control integrated with EPS controller

摘要

A system and method for generating an overlay torque command for an electric motor in an EPS system for use in a collision avoidance system. The method uses model predictive control that employs a six-dimensional vehicle motion model including a combination of a one-track linear bicycle model and a one-degree of freedom steering column model to model the vehicle steering. The method determines a steering control goal that defines a path tracking error between the current vehicle path and the desired vehicle path through a cost function that includes an optimal total steering torque command. The MPC determines the optimal total steering torque command to minimize the path error, and then uses driver input torque, EPS assist torque and the total column torque command to determine the torque overlay command.

主权项

1. A method for providing a torque overlay command in a collision avoidance system that is at least part of a torque command provided to an electric power steering (EPS) motor on a vehicle, said method comprising:
providing a mathematical model of a vehicle steering system; determining a difference between a current vehicle path and a desired vehicle path; providing model predictive control to determine an optimal total column torque command for the motor that minimizes the difference; providing an EPS torque assist command based on vehicle speed; determining the torque overlay command using the optimal total column torque command, a driver provided torque and the EPS torque assist command for a particular vehicle speed, where determining the torque overlay command includes solving a nonlinear algebraic equation given by:
ƒ(TBT+TO)+HWT+TO=TT  where TBT is the driver provided torque, TO is the torque overlay command, HWT is hand-wheel torque, TT is the total column torque command, and ƒ is a function defining the EPS torque assist command, and a Newton-Raphson iteration technique is used to solve the equation; and providing the total column torque command to the EPS motor.