### Research Gaps and Contributions  
Although significant advances have been made in the fields of nonlinear control and DT technologies for robotics, several important research gaps remain unaddressed. Firstly, most existing DT and HIL implementations rely on high-performance or licensed hardware platforms, which limit their applicability in educational or resource-constrained settings [4; 5; 38]. Secondly, while HIL methodologies have proven effective in validating control strategies, their integration with nonlinear controllers and DTs remains limited. Many controls validation setup operate under assumption of ideal communication conditions, such as negligible latency and perfect synchronization between plant and controller [39]. As a result, the transition from simulation to physical implementation can reveal instabilities. Finally, the separation of controller and plant models across different hardware platforms introduces unnecessary complexity and increases implementation costs. Few studies have explored the feasibility of integrating both components into a single low-cost embedded system, which could streamline design and optimize resources [40]. As shown in Table 1, the current literature lacks a comprehensive examination of using platforms like the Raspberry Pi for implementing DT in nonlinear control of mobile robots.  
In this context, the paper proposes a complete methodology for the design and validation of nonlinear controllers within a HIL-DT framework. The use of a RBP as a unified platform for hosting both the controller and the virtual process offers a low-cost and scalable solution, enabling greater access to advanced control techniques. The goal is to test the tracking of nonlinear path trajectories of the wheeled differential driven robot P3-DX. The electronic control solution is validated through a three-stage process: simulation, DT testing, and real-world experimentation.  
The main contribution relates to the application of the cost-effective yet robust electronic platform RBP, serving dual purposed: (a) electronic control unit (ECU-RBP) connected wirelessly to the plant under examination and (b) DT-RBP emulating the robot behaviour as a realistic approach for validating the remote closed-loop control prior to the implementation of the real robot, following the HIL-DT concept. The methodology incorporates practical uncertainties, such as variations in battery levels, mechanical backlash, and wireless communication delays, into the experimental workflow. This enhances the realism and robustness of the validation process. Furthermore, the integration of Simulink support packages for RBP streamlines code generation and deployment, facilitating rapid prototyping, and the development of the RBP.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ref.** & **Focus Area** & **Research Objective** & **Sorting** \\ \hline
[1; 2; 3; 29] & Automotive & HIL for ESC systems & No \\ \hline
[4; 5] & Education & Robotic HIL & No \\ \hline
[8; 9] & Power Systems & HIL DC and Grid & No \\ \hline
[13; 14; 15] & Control Modeling and Optimization & DT in control & No \\ \hline
[30; 31; 32; 33; 34; 35; 36; 37] & Robotics & Trajectory Tracking & No \\ \hline This research & Electronic Control & HIL, DT & Yes \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of the relevant literature.  
ing and reducing development time. Together, these contributions advance the state of the art in accessible, realistic, and robust validation of nonlinear robotic control systems.  
The remainder of this paper is structured as follows. The resources and methodology are described in Section 2; Section 3 presents the experimental results; and finally, the discussion and conclusions of this study are presented in Sections 4 and 5, respectively.