# Design and Implementation of a Lizard-Inspired Robot
## 4 Results of the Experiments and Discussion
### Clockwise Turning Locomotion  
The third experiment verified the clockwise turning locomotion of the robot. The purpose of this experiment was to prove that the robot was capable of repeating clockwise turning locomotion. The parameters of the input angle function for the experiment were set as follows:  
\[\alpha =\frac{\pi}{6},\] \[\omega =10,\] \[\beta =-\frac{\pi}{6}.\]  
The parameters show that the robot turned in the clockwise direction. The locomotion time of the robot was set to 4 s. Clockwise turning locomotion was repeated 10 times. Table 6 shows the results of the experiments. Figure 23 shows the trajectories of each marker in the ninth experiment, where the \"\(\times\)\" marks represent the locations of the robot coordinate with respect to each half period of the input angle function. Figure 24 shows the time variation of the relative angle of the \"\(\times\)\" marks in Figure 23, that is, the time variation of the turning angle in the ninth clockwise turning locomotion. Figure 25 shows a snapshot of the clockwise turning locomotion experiments.  
From Table 6, it can be seen that the average of the 10 clockwise turning locomotion experiments was \(-0.262\) rad, with a standard deviation of \(0.001\) rad. Hence, the fabricated robot possesses high repeatability regarding clockwise turning locomotion with respect to the parameters of the input angle function. In addition, the ideal turning angle of the clockwise turning locomotion obtained by the kinematics analysis was \(-0.271\) rad, and the error ratio between the average of the experiments and the ideal turning angle was \(3.16\%\). Since the error ratio was almost equal to the value in the forward locomotion experiment, the error in this experiment was also caused by the deflection of the carpet. Figure 23 shows that the robot turned in a clockwise direction. Figure 24 shows that the turning angle during the clockwise turning locomotion largely remained at the ideal angle. Hence, this experiment's results guarantee that the fabricated robot is capable of turning in a clockwise direction with high accuracy.  
Figure 22: A schematic figure of the deflection generated by both walking and the fiber construction of the carpet. The supporting legs kicked the ground to walk, and the fibers were deflected. Due to this deflection, the robot moved backward marginally.  
Figure 23: The trajectories of each marker in the ninth experiment of the clockwise turning locomotion experiment. The “\(\times\)” marks represent the locations of the robot coordinate with respect to each half period of the input angle function. The relative angles of the “\(\times\)” marks (colored in blue) are the turning angles of the robot.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Number of Experiments** & **Turning Angle (Rad)** \\ \hline
1 & \(-\)0.263 \\
2 & \(-\)0.260 \\
3 & \(-\)0.262 \\
4 & \(-\)0.262 \\
5 & \(-\)0.262 \\
6 & \(-\)0.264 \\
7 & \(-\)0.261 \\
8 & \(-\)0.263 \\
9 & \(-\)0.264 \\
10 & \(-\)0.263 \\ \hline Average & \(-\)0.262 \\ Standard deviation & 0.001 \\ \hline Ideal & \(-\)0.271 \\ Error ratio (\%) & 3.16 \\ \hline \hline \end{tabular}
\end{table}
Table 6: The results of the clockwise turning locomotion experiments.