"Walking" Robot - Week 3 [Hopping Rabbit]

After creating the parts in Solid Works, we went ahead and printed them out. We assembled all the parts. Then we encountered six problems.

THE SIX PROBLEMS
1. The shaft on each side would spin at different rates.
2. Some more stable friction was needed in the front leg to not slip off the ground.
3. The back legs (larger legs) needed some more weight on the rear part. Otherwise, it the pointy front part would touch the floor when it moves forward and would flip over, causing a disaster.
4. It needed something springy on the bottom of its back side to support it. Otherwise, the body part would rotate instead of the legs rotating.
5. We needed to find out the right orientation of the front leg and the connecting rectangular piece (the one that connects the back legs to the motor shaft) in order for the rabbit robot to "hop."
6. We needed to find a place for the batteries. Since it was pretty heavy compared to the other parts of the robot, misplacing it could cause a serious balance issue.

Here are solutions that we came up for the problems.

THE SIX SOLUTIONS
1. Change the two separate shafts into one long single piece so that they spin at the same rate.
2. Stretch rubber bands and tape it onto the front legs for friction.
3. Drill 3 holes into the back legs. Add screws (head piece and the tightening piece) to the holes. Achieve stable balance either by adding or removing the tightening piece.
4. Use the red sponge form to support the body because it has the needed "springy" characteristic.
5. Since the shaft is hexagonal, experiment all six orientations and find out the orientation that would allow the robot to hop forward.
6. Observe carefully whether the body part leans forward or backwards when it moves forward. If it leans forward then place it on the back of it and vice versa.

When taking Solution #1 into action, we had some difficulties with our motor. It would make this loud noise when it is on. We later figured out that the motors were spinning in the opposite direction, and because of the friction, it was making the sound. We, therefore, had to sauter our wires again so that the motors would spin in the same direction.

When processing Solution #3, we added two screws (including the head piece and the tightening piece) for the middle and the back holes. We only added the tightening piece to the front most hole for the better balance in the leg when moving.

For solution #5, we did try all the orientations. The only orientation that would allow the robot to hop forward had the connecting rectangular piece (the one that connects the back legs to the motor shaft) 90 degrees before the front legs.

For solution #6, we observed the balance of the body part when moving forward and came to conclusion that it actually leans a little bit forward. So, we decided to place the batteries on its back side, which worked just fine.

We ended up not using the jumping legs that we created on Solid Works because out shorter legs were working just fine. We figured that rabbits don't necessarily have to jump as long as they can hop :)

We also tried to add some more decoration to our cute rabbit robot: something like its face and ears. But we ended up leaving it look "modern" and robot-like without much rabbit looking decoration for its balance.

Here are some pictures of our final outcome :)
We like it very much!

Here is a video of our hopping rabbit!