Command modification using input shaping for automated highway systems with heavy trucks

This paper presents a new method for maintaining and improving string stability by preventing actuator saturation in automated vehicles on highways. Instead of relying on feed-back controllers to deal with the issue of actuator saturation after the fact, reference commands are feed through an FIR filter called an input shaper so that harmful components in the reference commands are reduced or removed. Two methods (zero-placement and convex optimization) are compared for designing input shapers. In addition, a linear model of a 3-vehicle platoon is derived and analyzed explicitly from the standpoint of actuator saturation. A relatively short input shaper is designed and shown to prevent actuator saturation in exchange for a small delay in system response.