Code reorganization and Drone Logic Update

setup/install_ubuntu.sh

@@ -151,7 +151,7 @@ pip install --upgrade pip
 if [ -f "$PROJECT_ROOT/requirements.txt" ]; then
     pip install -r "$PROJECT_ROOT/requirements.txt"
 else
-    pip install pybullet numpy pillow opencv-python pymavlink
+    pip install pybullet numpy pillow opencv-python pymavlink pexpect
 fi
 
 echo "[INFO] Python packages installed"