## 5 Experiments
### Meat Cutting with Force Amplification Strategy  
As a knife mounted on the end-effector of a robot is inherently dangerous, the knife for the meat cutting experiments was always covered with a sheath when not in use to avoid accidental injury. When experiments were being performed, even if the user could stop the robot at any time by releasing the button, a second person always had his/her hand on the emergency robot switch to disable the robot if something goes wrong. The user also wore a protective gear around his arms. In addition, as a precaution, the robot was wrapped with a plastic sheet to prevent minute meat pieces from entering the internal structure of the robot. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & & \multicolumn{2}{c}{**Button 2**} \\ \cline{2-4}  & & **State 0** & **State 1** \\ \hline \multirow{3}{*}{Button 1} & Position 0 & \(K_{max},D_{max},\eta=0\) & \(K_{max},D_{max},\eta\) \\ \cline{2-4}  & Position 1 & \(K_{min},D_{min},\eta=0\) & \(K_{min},D_{min},\eta\) \\ \cline{2-4}  & & (used for positioning of knife) & (used for cutting) \\ \cline{2-4}  & Position 2 & \(K_{min},D_{min},\eta=0\) & \(K_{min},D_{min},\eta\) \\ \cline{2-4}  & & (used for positioning of knife) & (used for cutting) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Impedance shaping using joystick. Figure 16: Iterative procedure for tuning the two amplification factors for forces and torques. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**S.No.** & **Meat** & **Part** & **Side** & **Operation** & **FT Sensor Input** & **Force Amplification \(\eta_{f}\)** & **Torque Amplification \(\eta_{\tau}\)** \\ \hline
1 & Pork & Square & Right & Cutting & B & 20 & 3 \\ \hline
2 & Pork & Square & Right & Cutting & B & 20 & 3 \\ \hline
4 & Pork & Square & Right & Cutting & B & 15 & 3 \\ \hline
5 & Pork & Square & Right & Cutting & B & 10 & 3 \\ \hline
6 & Pork & Square & Right & Cutting & B & 20 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Determining the force amplification factor \(\eta_{F}\). **Experiment 1--Cobot assisted pork cutting**  
Figures 17 and 18 show the sequence of cuts of Experiment 1 and the corresponding temporal evolution of the XYZ-total forces applied by the user and measured by the B sensor, respectively. The terminology A cut, B cut, etc. in these figures are author defined to refer to the iteration of the cutting and not the cutting methods. Therefore, the images shown in Figure 17 do not represent one single cut in progress, but instead one image of each cut: they can be interpreted as cut 1, cut 2, etc. **Experiment 2--Cobot assisted pork cutting**  
In Experiment 1, it took the butcher (the user) 4 cuts to make 1 slice. Nevertheless, in Experiment 2 (see Figure 19), with the same section but from a different meat, it took him 9 cuts to make 1 slice (see Figure 20 for the corresponding temporal force evolution). This is due to the natural variation in the body composition from one animal meat to another and also how much forces the user wanted to apply for a single cut. Figure 17: Experiment 1—cobot assisted pork cutting. Figure 18: Forces applied by the user in Experiment 1. Figure 19: Experiment 2—cobot assisted pork cutting. Figure 20: Forces applied by the user in Experiment 2. Experiment 7--Foam cutting with intent prediction module  
For the previous meat cutting experiments with force amplification strategy we had a professional butcher as the user. However, for verifying the intent prediction strategy, we used a foam block and multiple users in order to perform the training of the LSTM network (see Figure 29 for the corresponding experimental setup). This foam reproduces the same type of shearing forces as meat cutting. As explained earlier, our intent prediction module uses RNN-LSTM units. For each user, we performed sample trials with foam cutting to collect the training dataset. The LSTM network was trained on this dataset to predict force values, similar to the prediction of force values of the Natural Motion dataset (NM-F) in [23].