# Design and Control of an Ultra-Low-Cost Logistic Delivery Fixed-Wing UAV
## 6 Conclusions and Prospects  
In this study, a development path is described for a DIY ultra-low-cost fixed-wing UAV for delivery missions. An advanced flight control system, based on LQR and MPC, was designed and implemented. Using sensors and actuators on the flight control board, the UAV is able to fly, stabilize, and operate autonomously, taking into account system uncertainties and disturbances. The parameters and algorithms of the flight control system are optimized by adjusting parameters, such as the weight matrix, prediction window, sampling time, and covariance matrix. The creation and implementation of a deep-learning-based image recognition system, utilizing the YOLOv8 algorithm and coordinate transformation technology, are outlined. The effectiveness and superiority of this UAV system are verified through simulation experiments and flight tests, which demonstrate the system's ability to accomplish target transportation and delivery. This system satisfies specific performance metrics and constraints with high accuracy, flexibility, stability, robustness, and utility. Each of these components is integrated into a cohesive system, making it unmatched by traditional methods in last-mile delivery applications. According to the test results, this paper draws the following conclusions:  
1. The total production cost of the UAV described in this paper is 101 USD, while the generation cost of the same type of UAV on the market is 280 USD, which greatly reduces the production cost and usage cost;
2. We designed a streamlined wing and dual vertical h-shaped tail, based on an accurate aerodynamic analysis, which has higher lift, strength, and stiffness and lower drag and lateral drag than the same type of aircrafts, in which our wing model parameterization meets the requirements and the results converge. The displacement reduces the  
Figure 34: Fixed-wing UAV results related to angles. fuselage oscillations, and the volume factor is reduced by 10% to 20%, which shows that the aircraft has a more optimized performance compared to the same type of commercially available aircrafts;
3. We designed an autonomous projectile mechanism and spring hinges, which are more flexible and protect the projected package compared to marketed UAVs;
4. After several test experiments, we found that the UAV optimized in this study has less deviation from the desired values and meets specific performance metrics and constraints. This demonstrates the superior control performance and structural design of the proposed UAV, highlighting the effectiveness and superiority of the autonomous flight algorithms and the implemented control laws. In addition, the UAV successfully performed target search and localization, demonstrating the accuracy and reliability of the image recognition system. Based on the precise target strike and smooth return to the base, the comprehensiveness and practicality of the UAV's design and control schemes proposed in this study are further verified. In future work, we can further improve the accuracy and robustness of the autonomous flight algorithm, as well as the scalability and compatibility of the flight control system, to enhance the flight function. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14114358/s1](https://www.mdpi.com/article/10.3390/app14114358/s1)]([https://www.mdpi.com/article/10.3390/app14114358/s1](https://www.mdpi.com/article/10.3390/app14114358/s1)), Video S1: P1140150; Video S2: P1140226. Conceptualization, Y.Z. ; methodology, Y.Z. and Q.B. ; software, Y.Z. and P.M.; validation, Y.Z. and Q.Z. ; formal analysis, Y.Z. ; investigation, Y.Z. ; resources, F.L. ; data curation, Y.Z., Q.Z. and P.M.; writing--original draft preparation, Y.Z. ; writing--review and editing, Y.Z., Q.B. and S.P. ; visualization, Y.Z. ; supervision, Q.B., F.L. and S.P. ; project administration, Q.B., F.L. and S.P. ; funding acquisition, Q.B., F.L. and S.P. All authors have read and agreed to the published version of the manuscript.