## 5 Conclusions  
Aiming at the special steep ascent and descent flight process of distributed dynamic fixed wing UAV, this paper carried out the UAV dynamics modeling, jump and descent performance analysis, control strategy design, control law design and flight simulation research. The main research conclusions are as follows:  
(1) Considering the influence of propeller slipstreams on the local angle of attack, sideslip angle, and velocity distribution, a coupled distributed dynamic slipstream model of the entire aircraft aerodynamic force and torque was established, and the lift model in the slipstream area was modified through ground slipstream experiments. Further ground sliding tests and low-speed climbing flight tests were conducted using experimental prototypes, and the experimental data showed that the established unmanned aerial vehicle (UAV) maneuvering mechanics model can accurately reflect the motion laws of the UAV.  
(2) Through simulation analysis of the stability and dynamic control characteristics of the drone's static control, as well as the balancing characteristics during takeoff and  
Figure 33: Digital simulation of the steep descent process.  
descent, it is confirmed that the drone has the ability to climb at low speeds with small climb angles and large pitch angles, as well as the ability to descend sharply at large angles.  
(3) Based on the control capability of distributed-power fixed-wing unmanned aerial vehicles equipped with multiple power sources and control surfaces, a comparative analysis was conducted on the longitudinal and lateral heading control efficiency of the UAV's rudder deflection and power differential, as well as the impact of the UAV's angle of attack on the control efficiency of each rudder surface and power differential. A control scheme was determined to use \"elevator for longitudinal control, ailerons for lateral control, and a combination of left and right power differential and rudder for heading control\".  
(4) Attitude and trajectory control laws for distributed-power takeoff and descent unmanned aerial vehicles were designed, and digital simulation research on the takeoff and landing stages of unmanned aerial vehicles was completed. The digital flight simulation results show that both the attitude controller and position controller of the drone have fast response capability and strong robustness. Based on the designed takeoff and landing controller, the drone can basically track the drone's jump and steep descent strategy and complete the jump and steep descent task.  
Conceptualization, Y.G. and X.X.; methodology, X.C. and Y.G.; software, X.C. and Y.H.; formal analysis, X.C.; writing--original draft preparation, Y.G., X.C. and X.X.; writing--review, X.X. and Y.H.; Visualization, X.C. and Y.H.; supervision, Y.G., X.C. and X.X.; project administration, X.X. All authors have read and agreed to the published version of the manuscript.  
The research was funded by the Shaanxi Natural Science Research Program (No. 2023-YBGY-373) and the National Key Laboratory of Autonomous Intelligent Unmanned Systems (No. 2024-SRIAS-KF-010).  
Not applicable.  
The data presented in this study are available in the figures shown in the present article.  
Author [PERSON] was employed by the company Aviation Industry Corporation of China Ltd. and author [PERSON] was employed by the company Xi'an ASN Technology Group Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.