Update ReadMe.md

ReadMe.md

@@ -89,6 +89,10 @@ and it is also necessary to link with the desired libraries by using the followi
 
 ``` TARGET_LINK_LIBRARIES(<executable name> ${<library name>_LIBRARIES}) ```
 
+## Procedures
+
+* [PTU-D46 calibration](doc/ptu_d46_calibration.md)
+
 ## Disclaimer  
 
 Copyright (C) 2009-2010 Institut de Robòtica i Informàtica Industrial, CSIC-UPC.