## 4 Conclusions  
This study presented a detailed analysis of the input polishing parameters (startup torque of rotatory gripper, wheel rotational speed, normal contact force, and gripper vibratory motion velocity)  
Figure 8: Predicted results against experimental results: (**a**) for polishing efficiency; (**b**) for torque. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Predicted Results** & **Experimental Results** \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Input optimal parameters \\ \end{tabular} } & Gripper startup torque (\(T_{g}\)) & 0.019 Nm & 0.019 Nm \\ \cline{2-3}  & Wheel speed (\(\omega\)) & 4500 rpm & 4500 rpm \\ \cline{2-3}  & Normal contact force (\(F_{z}\)) & 16 N & 16 N \\ \cline{2-3}  & Gripper velocity (\(V_{f}\)) & 5 mm/s & 5 mm/s \\ \hline \multicolumn{2}{c}{Polishing efficiency (\(PE~{}=AAR_{a}/T\))} & 0.976 & 0.943 \\ \hline \multicolumn{2}{c}{Polishing Torque (\(T\))} & 0.50 Nm & 0.47 Nm \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Conformation test results for the optimal polishing parameters. Figure 9: Watch bezel: (**a**) before polishing and (**b**) after robotic polishing. on the polishing efficiency and torque for the proposed robotic polishing system by using Taguchi design of experiments (DOE). The proposed robotic polishing system is tested for the watch bezel. Experimental results analysis by signal to noise ratios optimizes the responses and closely matched with the ANOVA results that further legitimized the experimental study. Additionally, regression line equations are added to model the response behavior of the polishing efficiency and torque for the input polishing parameters. Finally, a confirmation test is conducted for affirming the authenticity of the experimental results and to check the regression model by comparing the experimental result and predicted result at optimal levels of the input factors. From the above results, analysis, and discussion, the following conclusions can be drawn:  
1. Robot polishing is a challenging task that requires precision, as well as the consideration of polishing surface coverage, controlled polishing force, and best polishing parameters. The presented polishing system with optimal polishing parameters is effective and finishes the polishing job in a short time with precision. 2. The _S/N_ ratios analysis from the Taguchi method shows the best levels of the control factors for highest polishing efficiency (_PE_ = 0.943) as: start-up torque of rotatory gripper = 0.019 Nm (_S/N_ = -2.451), wheel speed = 4500 rpm (_S/N_ = -2.066), normal contact force = 16 N (_S/N_ = -1.312), and gripper velocity = 5 mm/s (_S/N_ = -2.642). Similarly, the best levels of the control factors for the minimum torque (_T_ = 0.47 Nm) as: start-up torque of rotatory gripper = 0.019 Nm (_S/N_ = 9.049), wheel speed = 4500 rpm (_S/N_ = 9.398), normal contact force = 16 N (_S/N_ = 12.278), and gripper velocity = 5 mm/s (_S/N_ = 9.160). 3. According to the ANOVA statistical model, selected optimal levels for each control factors are same as in Taguchi method. It further determines the ranks and % contributions of the control factors for polishing efficiency (_F\({}_{z}\)_: rank = 1 and % = 71.56, \(\omega\): rank = 2 and % = 19.96, \(T_{g}\): rank = 3 and % = 3.93, and \(V_{f}\): rank = 4 and % = 0.57) and torque (_F\({}_{z}\)_: rank = 1 and % = 90.54, \(\omega\): rank = 2 and % = 3.01, \(V_{f}\): rank = 3 and % = 1.12, and \(T_{g}\): rank = 4 and % = 0.66). 4. Polishing efficiency is given higher preference over polishing torque, therefore the overall system input parameters for good polishing efficiency and torque are as: startup torque of rotatory gripper = 0.019 Nm, wheel speed = 4500 rpm, normal contact force = 16 N, and gripper velocity = 5 mm/s. 5. The most significant control factor which contributes more to the polishing process in this system is the normal contact force applied by the polishing wheel following the wheel speed, gripper torque, and gripper vibratory velocity.