University of Puerto
Rico
Mayaguez Campus
Electrical
Engineering Department
Undergraduate Research INEL 4998
Nitinol Propelled Hexapod Robot
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To better understand the behavior of this robot, we divided the analysis into two different parts. First we considered the physical characteristics of the Nitinol, which is the material that actually propelled the robots. Then we described the mechanical characteristics of the robot itself to understand how it walks. This should provide us with sufficient information to determine if the robot can be successful.
The first step in building the robots was to cut all the tubing, since it was the most time consuming. These pieces were sanded to remove small pieces of metal that resulted from cutting. Measurements were taken to determine the amount of spare parts we had for repair in case something went wrong. Then we started bending the wires that give support to the robot. These wires, which are actually the legs, were then inserted into the body of the robot. The next step was to cut the Nitinol and to connect it to the robot by the leg and body crimps. The last step was connecting the control wires to the robot and the manual controller. The control wires were also sanded to allow proper current conduction.
We followed a detailed procedure for analyzing the three robots. First we determined what kind of walking sequence the robots would have. The sequences selected depended on the degree of variation between them and on the potential they could have on an application. Since the sequences would be different for all three robots, they should give us an idea of the potential the robots could provide. The current needed for each model was also measured. After building the robots with the three different sequences, we measureed their speed. We selected a common surface on which to test the robots. We chose a porous book cover that seemed to provide us with both traction and smoothness. The electric pulses applied were equally spaced and lasted the same amount of time. Pulling force was then measured taking a small weight and letting it hang freely with a pulley. As the robot walked, the weight was raised. If we increased the weight, the estimated maximum pulling force was measured.
After all the physical calculations are made, an important part of the investigation took take place. This was deriving a mathematical model that will predict the behavior of the robot. |
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