2. Table of Contents  Linear Actuator  Base  Arm/Elbow Joint  Future Plan

3.  Previous Issues: Rack and gear meshing slop Uniform linear movement through bearings Drive motor needs replacement  Improvement Ideas: Mount second gear to face of primary gear Replace linear roller bearings with sleeve bushings Replace motor with higher torque version Linear Actuator

4. Fasten new gear to primary gear to increase contact area of gear to linear rack Chose sleeve bushing to increase surface contact on rack to increase stability Will reduce twisting and bending slop Eliminate linear ball bearing for smoother motion

5. Current motor is inopperable 256:1 Motor ordered to replace the 64:1 motor previously in place. Higher Torque, but lower speed

6. Base Setup

7. POT Drive Gear Current Base Setup ~1/8” slop from lazy susan

8. Drive Gear New Base Setup

9. Direct Drive Motor Base Plate Connection Drive Bearing Moving part of motor

10. Arm/Elbow Problems  1/8in arms Arm twists too much Not rigid enough assembly  Elbow helical gears Creates lateral loads on arm Low gear ratio results in small torque increases Exposed gearing picks up debris

11. Quick Fix Ideas  Channel Arm Idea Lighter, strong, resists torsion, but hard to make  Square Tube Idea Heavier, strong, and easier to make

12. New Arm 1 st iteration

13. Progress so far

14. Test Assembly: Chipping Rock Goal: Replace the linear actuator with a more powerful assembly to break rock.

15. Future Milestones  1 st Iteration redesign – Nov. 28th th  Interim Report Fall Semester – Dec. 9 th  Final Design Decision – Dec. 2008  Senior Design Expo – May 2008