- Step 1: Functional Requirements. Design a mechanism that meets the following requirements:
- Autonomously travels 4.9m on the designated track. The track will be on display in the lab. The track will have a slight incline and decline on it. The change is height will be no more than 3.1 mm. Autonomous means you cannot touch it once you start it. After your robot completes its first 4.9m, you must pick it up and move it to the start line to complete its second trial.
- is bio-inspired. This must be clear! Good examples in the past were centipedes, inchworms, sloths, ants, and scorpions. Wheels are not allowed. This is very open ended.
- Has the ability to be disassembled. That is, all servos and electronics must be capable of being disassembled. No glue on servos, servo horns, or electronics. And no tape!
- Step 2: Generate Solutions. Identify at least two animals that meet your functional requirements. For each animal, sketch by hand a solution that might meet the functional requirements. These should be done using the isometric sketching techniques we covered in class. Be sure to identify any key features of the designs.
- Step 3: Analysis
- Draw a Hildebrand Gait plot for one gait for each of your two designs.
- Identify if the posture of your robot is sprawled, upright, or something in between.
- Identify the convex contact polygon for each of your gaits. Prove that the system will be statically stable at all times by showing me through drawings that the center of mass is always in within that convex contact polygon. This needs to be done for all possible permutations of the convex contact polygon.
- Identify the force and torque requirements for the actuators. To do this, you need to create free body diagrams for each design.
- Keep it simple!
- I have purchased 1/8" and 1/4" MDF for this assignment. You are free to use other materials, but this is the only material that will be made available to you.
- I have also purchased the following shoulder screws from McMaster: 93897A238, 93897A256, 93897A265, 93897A273, 93897A281. You will find them in the CAD package above
- Excess mass is still an issue. You will have to move a device using MDF with low powered servos. MDF is heavy, you will have to keep your device light.
- Keep it small! There is no need for a large device. The servos are not strong enough to move a large device.
- 1/8" MDF is a lot easier to cut than 1/4" MDF. Use the 1/8" whenever you have the chance.
- It is impossible, yes impossible, to have multiple continuous servos match their speed. Do not design a system that uses multiple continuous servos. There will be nothing but problems.
- 2 hand sketches
- 2 Hildebrand Gait Plots
- Analysis of static stability
- Analysis for torque measurements.
- become more proficient at hand sketching
- apply static force and moment analysis to an open-ended problem
- solve an open-ended design problem that has many "right" answers
- understand the bio-inspired design process
- understand the importance of removing unnecessary material: light-weighting
- learn about animal gaits