# Development of an Autonomous Driving Smart Wheelchair for the Physically Weak
## 5 Basic Performance Experiments and Results of the Implemented System
### Obstacle Bump Climbing during Autonomous Driving  
The autonomous driving function was used to examine the wheelchair system performance in moving over an obstacle bump. Because the existing goal was to drive by going over an obstacle bump of 15 mm or higher, we prepared different bump heights, 21 mm, 30 mm, 40 mm, and 51 mm, to conduct the experiment. Figure 13 shows photographs of the measurements of the prepared bumps.  
The experiment was conducted in the environment shown in Figure 14. We checked whether the system that stopped in front of the obstacle could be driven by going over each obstacle with both the front and rear wheels. Figure 15 shows the experimental results. The robot moved over the obstacle bumps with heights of 21 mm and 30 mm (the total driving distance was 1.9444 m and 2.01 m for the bumps of 21 mm and 30 mm, respectively, confirming that the robot drove more than 1211 mm of the total length of the system). At a height of 40 mm, only the first wheel and mid-wheel went over the bump (total driving distance: 1.005 m), and at a height of 51 mm, none of the wheels went over the bump (total driving distance: 0.01 m).  
Figure 12: Circle with target turning radius.  
Figure 13: Photographs of the measurements of the prepared bumps. (**a**) 21 mm bump and 30 mm bump, (**b**) 40 mm bump and 51 mm bump.  
The obstacle bump jumping experiment was performed 13 times per bump in the autonomous driving condition and 13 times in the manual driving condition. Thirteen experiments were conducted in such a way that, after performing three experiments on each bump, the results were checked, and then ten experiments were performed again to verify the results. The same results were obtained 13 times, confirming that the results were not affected by a specific experiment round or the surrounding environment. Even in the manual driving condition, the same results as those found in the automatic driving condition were confirmed, and through this, it was confirmed that the obstacle bump overcoming function is the performance of the system itself regardless of the driving mode. This can also be proven by the fact that the 40 mm and 51 mm bumps that the system did not cross are lower than the recognition range of the LiDAR sensor and cannot be recognized as an obstacle (LiDAR sensor mounting and detection height: 340 mm from the  
Figure 14: Experiment set-up.  
Figure 15: Experiment results (blue straight line: distance traveled versus time when crossing a 21 mm obstacle, red dot line: distance traveled versus time when crossing a 30 mm obstacle, green long dot line: distance traveled versus time when crossing a 40 mm obstacle, and purple dash-dotted line: distance traveled versus time when crossing a 50 mm obstacle).  
ground). However, because of the size of the front wheel and the performance of the motor, it was deduced that the highest bump (51 mm) could not be exceeded. In addition, the fact that the bump of 40 mm exceeded the middle was also due to the motor performance. Assuming that the autonomous driving electric wheelchair is used to move to the outside within a short distance, it is necessary to improve the motor performance and change the wheel design so that it can exceed the 50 mm bump.