Robust Controller Design for Non-Minimum Phase UAV System and System Analysis.

Different from other references that use Ziegler-Nichols method or another trial and error method to design the proportional-integral-derivative (PID) controller, this paper is based on the precise controller design in combination with the root locus criterion. According to the system properties and the task requirements, we applied the model reduction method, root locus criterion, root contour, pole-zero placement, frequency response, and orthodox PID criterion to design various controllers. Besides, we analyzed the system responses in a time domain to obtain the optimal controller parameters. We also designed a robust controller to give the system better relative stability through the comparisons of system performances in the frequency domain. Furthermore, in this paper, we also created the reverse gain PID controller to deal with the negative effects of the non-minimum phase system. Not only does this controller improve both the transient response and steady-state error but also enhance the relative stability of the system at the same time. Finally, according to the system properties, this paper can make the controllability of UAV much better by a variety of design methods and flexible controller applications, and then expand the application fields and scopes of UAVs. In sum, the research content is academic, practical, and very efficient as it can be used as reference material that can be applied in further follow-up research.