add robot arms

topics/04_mechanical/index.md

@@ -64,10 +64,19 @@ Optically tracked touch probes
 Bridge Coordinate Measuring Machines (CMM)
 <img src="images/bridge_cmm.jpg" alt="Bridge CMM">
 
+
+
 ### Digitizer Arms
 
-Passive Robot Arm
+Passive Robot Arm<br>
+<img src="images/portable_robot_arm.png" alt="Portable Robot Arm">
+
+
+<img src="images/gage_faro_arm.png" alt="Gage Faro Arm"><br>
+
 
+Typically, robotic arms used in manufacturing offer working volumes ranging from 4 to 12 feet, with radial reach extending from 2 to 6 feet. These arms predominantly come in six- or seven-axis configurations, depending on the specific requirements.
+Fixed Coordinate Measuring Machines (CMMs) excel in providing extreme precision, surpassing that of portable CMM arms.
 
 ### DIY