Heavy-duty truck control: short inter-vehicle distance following

This work presents implementation of truck longitudinal control for short distance following, which is a very difficult issue. The main difficulties are (a) low power/mass ratio; (b) time delay caused by and internal engine control and actuators like air brake; (c) prominent disturbance during gear shifting, wind and slight road grade. To overcome those difficulties, a complicated nonlinear vehicle dynamics model has been adopted to reduce the model mismatch on one hand. On the other hand, robust stability margin is enhanced in control design phase. A reliable and precise distance measurement is critically required for automated vehicle following. This has been achieved by filtering and fusing both Doppler radar and laser radar with Kalman filter. Experimental work with two trucks shows that this approach is effective. Two heavily loaded trucks are used for constant inter-vehicle distance following test. The controller performance is good even for 3m inter-vehicle distance. Although there are only two trucks tested, there is still a string stability problem because the leader truck is following a reference speed trajectory. The practical string stability study in previous work still applies. Experimental work has been presented.