Final Design Concept

For the final design, we kept most of the initial design concepts except for the tail mechanism. The tail mechanism was changed to a simple rocker mechanism as shown in Figure 12.

Figure 12. Simple Rocker Mechanism.

We chose to use this design rather than the arm mechanism design because this mechanism would produce a true rocking motion, as opposed to the climbing motion of the arm mechanism. The implementation of the tail mechanism involved the use of bevel gears to switch planes to the backside of the monkey to swing to tail. The rocking motion of the tail was synchronized with the motion of the arms - the tail would swing to the side of the pulling arm to balance the weight of the monkey. The implementation can be seen in Figure 13.

Figure 13. Tail Implementation

The bevel gear was attached to the housing using a bolt and pin clip. The pin joint on the bevel gear was similarly implemented as the arms. This joint again used a ball bearing, a rod eye, and O-rings to hold the rod in place. The rotating turntable served as a rotating, grounded joint. The final joint connected the wooden rod to the tail, and was implemented using two rod eyes and held in place using O-rings.

After initial testing of the climbing mechanism, we found that the robot weight was imbalanced. This imbalance caused the monkey to tilt backwards which made its arms ineffective. Wheels were added to the side of the robot to stabilize it against the ladder. These wheels were taken from pulleys. The ladder rungs were spaced 3" apart, and the rung spacing was determined by the using the MATLAB code and through initial testing.

                 Figure 14. Ladder.                                Figure 15. Close up of Pulley Wheels.

Finally, the internals of the final build are shown in Figure 16.

Figure 16. Internals of Monkey Robot