This paper proposes a systematic approach for identifying the translational dynamics of a novel two-layer octocopter. Initially, we derive the non-linear theoretical dynamic model of the conventional octocopter using the Newton–Euler formulation, aimed at obtaining a simplified model suitable for tuning PID gains necessary for controller implementation. Following this, a controller is designed and tested in the Matlab/Simulink environment to ensure stable flight performance of the octocopter. Subsequently, the novel octocopter prototype is developed, fabricated, and assembled, followed by a series of outdoor flight tests conducted under various environmental conditions to collect data representing the flight characteristics of the two-layer vehicle in different scenarios. Based on the data recorded during flights, we identify the transfer functions of the translational dynamics of the modified vehicle using the prediction error method (PEM). The empirical model is then validated through different flight tests. The results presented in this study exhibit a high level of agreement and demonstrate the efficacy of the proposed approach to predict the octocopter’s position based only on motor inputs and initial states of the system. Despite the inherent non-linearity, significant aerodynamic interactions, and strongly coupled nature of the system, our findings highlight the robustness and reliability of the proposed approach, which can be used to identify the model of any type of multi-rotor or fixed-wing UAV, specifically when you have a challenging design.

Resistance spot welding is one of the most common welding techniques used in the automotive and aviation industries. In the present research, the effect of resistance spot welding parameters such as, holding time, squeeze time, welding current, force applied, and welding time will be examined using Simufact Welding 2020, a welding simulation application. The impact of these parameters on the strength of the weld in metal sheets are studied. Each parameter was studied separately by changing one parameter within the range values and other parameters as constant values. It was found that the best region for the following spot-welding parameters is, from 0.9 s to 0.95 for squeeze time, 6.5 kA to 7.5 kA for welding current, 0.15 s to 0.4 s welding time, 30 ms for holding time, and 3.2 kN to 3.4 kN for electrode force. These parameter ranges are best to provide a spot weld with the highest yield stress.