CAD, Prototyping and Final Model
Computer Aided Design
After agreeing to pursue with the SAM mechanism, I decided to CAD the walker mechanism with two legs and the legs were a 180 degrees off from each other. This way at every instance there was at least one foot in contact with the ground.
After the initial prototyping we realized that the motor was too slow and unstable. So I re-CADed the motor and crank gears and as seen on the top right picture, the gear ratio was close to 1:1 and this made the walker faster and more stable too.
Prototypes and Final Model
Laser Cutting Time Lapse
Laser Cutting Time Lapse
Prototype 1
Prototype 1
The first prototype made was a low fidelity prototype to ensure that the four bar linkage on the automaton works. As seen in the figure to the left, the prototype was designed and painted on cardboard
Prototype 2
The second prototype contained the walker and automaton combined together for the first time. This prototype was not fast enough and too unstable.
Final Model
All models lined up
After many iterations I perfected the walking mechanism and altered the gear mechanism to created a faster walker. In the end our project won the speedster competition. For our model we chose a speedracer theme and cyclist to speak out to children and inspire them to pursue engineering. However, the hand moving mechanism kept failing repeatedly because the belt which was supposed to drive the crank was not fit tightly and this resulted in the belt slipping off the intended track. The belt which we bought had to be adjusted by cutting and sticking it back. For future cases I would like to take in consideration of the parts such as the belt which is harder to alter its size, while designing mechanisms. Apart from this one setback, we had a walking mechanism which was fast, but we forgot to consider the fact that the motor was on one side of the walker and this made the walker not in a straight line.