Incremental Nonlinear Dynamic Inversion (INDI) is a control approach that has gained popularity in flight control over the past decade. Besides the INDI law, several common additional components complement an INDI-based controller. This paper, the second part of a two-part series of surveys on INDI, aims to summarize the modern trends in INDI and its related components. Besides a comprehensive components specification, it addresses their most common challenges, compares different variants, and discusses proposed advances. Further important aspects of INDI are gain design, stability, and robustness. This paper also provides an overview of research conducted concerning these aspects. This paper is written in a tutorial style to familiarize researchers with the essential specifics and pitfalls of INDI and its components. At the same time, it can also serve as a reference for readers already familiar with INDI.

This paper, the first-part of a two part series of surveys on Incremental Nonlinear Dynamic Inversion (INDI), provides an overview of the evolution and developments in INDI. Written in a tutorial style, it presents different basic INDI variants and their specifics, such as model-based INDI, sensor-based INDI, and hybrid INDI. Furthermore, it sets these different approaches in context with each other. Later developments of INDI explicitly consider actuator dynamics. Those concepts are summarized and discussed in detail. Subsequently, studies that relate INDI to other control methods are summarized. Finally, an overview of various applications of INDI is given, covering different types of control loops and various types of vehicles and plants. This paper seeks to set these developments into context with each other. The purpose of this paper is twofold. INDI is already well-known in the domain of flight control but less so in other fields. Therefore, the paper is written in a comprehensive tutorial style to provide easy access to readers unfamiliar with the topic. On the other hand, the paper can serve as a reference for readers familiar with the topic.