Real-time Nonlinear MPC For Extreme Lateral Stabilization of Passenger Vehicles

Real-time Nonlinear MPC For Extreme Lateral Stabilization of Passenger Vehicles

Zheng, Yanggu (TU Delft Mechanical, Maritime and Materials Engineering)

Shyrokau, B. (mentor)

Delft University of Technology

Mechanical Engineering | Vehicle Engineering

2018-07-02

Loss of lateral stability is still a major cause of road accidents in recent years. Nonlinear
model predictive control (NMPC) is regarded as a powerful tool to improve vehicle safety by
fully utilizing the tire-road friction. However, the computational load is excessive for on-board
hardware, thus NMPC is yet distant from real-time implementation in vehicle control. To
tackle the problem, this study proposes a method to improve the computational efficiency
in NMPC. First, a lookup table of initial guess of the NMPC solution is calculated based
on a piecewise-affine (PWA) approximation of tire’s nonlinear behavior. Then, a local optimization
process starting from the initial guess searches for the optimal control input, using
perpendicular search plus line search method. The proposed method was examined through
a set of numerical tests and in real-world scenarios using experimentally calibrated multibody
model. The code was also tested on dSPACE for proof of real-time implementation. Results
show a significant reduction in computational time, thus real-time implementation has been
achieved with a huge margin. The loss in the accuracy of the optimal solution is negligible.
The performance in improving vehicle safety is promising too, as the vehicle can be recovered
from unstable motion with body slip angle up to 30 degrees.

http://resolver.tudelft.nl/uuid:3d5ac5f7-fe9b-4986-a957-7d47da653b72

Student theses

master thesis

© 2018 Yanggu Zheng