Overview
The aim of this project was to design a leg that would meet all the requirements of the group project while travelling 1 meter in as little time as possible. We were then to calculate how fast our designs would go in theory, test them and improve them.
Report 1
Preliminary Design and Explanation
I decided to choose design 6 as my best design when compared to the others as I believe that it is the most well rounded design of those I have created. Starting with its strengths, design 6 is very round on all the surfaces touching the ground, this will allow it to more easily roll and push itself along as it progresses. It is also one of the lighter designs as it allows for the large cutout in the center that has saved a lot of weight compared to some of the others which only allowed for smaller cutouts at the top. It was also designed to not use the mating part to save weight thus the leg would be mounted directly to the motor. As for weaknesses it is relatively long which may cause it to struggle at times when rotating, it also has many rounded edges which may cause it to slip when rotating negatively affecting its ability to move. Since it is mounted directly to the motor the PLA may be damaged as it is of lesser quality than the material the mating piece is made of. In order to help with some of these weaknesses an improved design could implement spikes on some of the rounded edges to eliminate the possibility of slipping as well as use curves with smaller radii in order to keep the length of the design down and keep it more stable.
Report 2
Improved Design and Explanation
This design I have presented is very different from the original design I created for the first assignment. After the lectures I decided to look back at my design and realized my design was too complicated and not very well optimized for speed. Thus I went from the “leg” style of design to a more “pie” type of design. I decided to go for a pie style design because it incorporated the two aspects discussed in class for more speed (longer leg and increased ground contact radius) and was more effective at using these dimensions than the straight leg design. Some dimensions that could be adjusted for better speed are arc length and length of the leg. I could also add texturing to increase the coefficient of friction between the leg and floor to reduce any slipping and thus loss of movement when the leg rotates as that has a significant effect on distance traveled. Height affects the speed because it changes how much ground is covered by the leg in one rotation of the leg, thus the longer the leg is the more ground can be covered in one rotation propelling the robot faster if that length is longer. This is similar to how larger wheels cover more ground in one rotation than smaller wheels.
Report 3
Test Results and Final Design
Throughout the testing phase, I observed that my leg often tended to veer off to one side, although the specific side it inclined towards varied randomly across multiple attempts. As the leg continued to move, it exhibited a tendency to self-correct slightly, steering toward a straighter path, albeit not perfectly. This self-correction seemed to result from the legs losing synchronization as the robot progressed. Consequently, if the course extended, the veering would occur in the opposite direction.
Additionally, I noted that the legs experienced a considerable amount of slippage during movement, resulting in a noticeable loss of speed. The slippage primarily occurred when the curved edge of the leg was in contact with the ground as the robot 'walked.'
Furthermore, the stability of the robot decreased over time. Initially stable, the robot gradually became wobbly and unstable. This instability appeared to be caused by the misalignment of the legs towards the end of the course, leading to the body wobbling and hitting the ground.
