## 5 Conclusions and Future Work  
This study aimed to evaluate the effectiveness of various interaction methods for wheelchair users in virtual environments, utilizing a haptic feedback system designed to enhance immersion and user experience. The methods compared were using the wheelchair with base motors on (C1), using the wheelchair with base motors off (C2), and control via joystick (C3). The results from these comparisons provide several significant insights into the performance and preferences of wheelchair users in virtual settings. The comparison between C1 and C2 revealed a notable improvement in user performance when the motors were off. Users navigated through the virtual environment significantly faster without motor assistance, suggesting that the absence of base motors reduced resistance and allowed for more natural and controlled movements. The large effect size ([PERSON]'s d = 1.036) and high statistical power (96.1%) underscore the robustness of these findings, indicating that users have a clear preference for moving without motor assistance in virtual environments. In the comparison between C1 and C3, the results showed that users performed better with the base motors on. Although this method did not match the effectiveness of having the motors off, it still provided better control and faster navigation times compared to using a joystick. The substantial effect size ([PERSON]'s d = \(-\)0.988) and statistical power (94.4%) reinforce the reliability of these results, demonstrating that natural interaction methods are generally more effective than joystick control. This suggests that while motor assistance might not be ideal, it is still preferable to alternative control methods like joysticks. The most striking results emerged from the comparison between C2 and joystick control. Users exhibited significantly better performance with the motors off, as indicated by much faster navigation times and very large effect size ([PERSON]'s d = \(-\)1.803). The statistical power of 96.8% confirms the strength and reliability of these findings, emphasizing that joystick control is the least effective method among those tested. This substantial difference highlights the importance of enabling users to interact with virtual environments in a manner that closely mimics their real-world movements. Qualitative data showed that 85% of participants felt more immersed using their wheelchairs with base motors due to natural movements. Observations noted a 20% increase in engagement behaviors. Additionally, 90% of participants found the haptic feedback system enhanced realism, particularly for varying terrains. These findings underscore the importance of natural interaction methods and advanced haptic feedback in improving VR experiences for wheelchair users. Despite the promising results, our study has certain limitations. First, while the system effectively simulates terrain-based haptic feedback, the virtual environments tested were relatively simple; more complex environments could pose additional computational challenges. Additionally, the user study involved a limited sample size, which may not fully represent the diversity of wheelchair users. Future research should focus on refining the haptic feedback system to further enhance user control and immersion. This could involve developing more sophisticated algorithms to simulate various terrain types and resistances more accurately. Expanding the study to include a larger and more diverse sample of wheelchair users will help to generalize the findings and ensure their applicability to a broader population. Additionally, it can be interesting to conduct this study with the motorized base integrated into our already constructed six-degree-of-freedom (6 DOF) motion platform, which can be seen in Figure 6. This setup allows for the simulation of more complex and realistic movement dynamics, including pitch, roll, and yaw, which could further enhance the immersion and realism of the virtual environment.