Arm and Finger Testing
Introduction
This test plan is for the arm and finger systems of robot. The plan involves testing different materials and designs to be used, as well as operating conditions. The design for the fingers has been selected, and initial prototyping has been completed. Problems with air flow were seen in this prototyping though, so design revisions were made and will be tested. Testing on the strength of the fingers will also be done. That is how much weight they are able to hold at a given pressure. Two different arm designs are currently being considered. The primary design is a four channel hexagonal shape. Initial prototyping has been done however, additional testing to determine the best suited material. The other potential design involves using a slinky with balloons attached internally as a way to extend the arm. Other parameters that will be found through testing are the reach of the arm as well as its ability to lift an object off the ground. For both the finger and arm, the optimal pressure to operate the systems at will need to be determined. Additionally, the amount of air needed to fully inflate the system will need to be found. This will be used in the design of other subsystems.
Objective
To quantify following engineering requirements:
# | Importance | Engineering Requirement | Unit | Target Value | Marginal Value | |
003 | 9 | Inflation time | s | < | 2 | 5 |
004 | 3 | Deflation time | s | < | 10 | 15 |
005 | 3 | Inflation arm reach | in | > | 6 | 4 |
006 | 1 | Object lift distance | in | > | 6 | 4 |
007 | 9 | Hand grip strength | N | > | 1 | 0.6 |
008 | 3 | Stored air volume | ml | > | 1200 | 600 |
009 | 3 | Stored air pressure | psi | < | 120 | 100 |
010 | 9 | Number of finger | units | >= | 3 | 3 |
Schematic
Figure 1: Finger Design
Figure 2: 4-channel Hexagonal Arm Segment and Example Arm
Plan
- Finish creating molds for fingers
- Make finger and arm segments with various materials
- Make arm from arm segments
- Test fingers for operating pressure and strength
- Test arm for operating pressure, reach, and lift capabilities
- Compare results from different materials
- Make a base to hold the arm as well as a base on end of arm for fingers
Predicted Outcomes and Expectations
- Material selection for arm and fingers
- Finalized design for arm and fingers
- Operating pressure for each subsystem
- Quantify abilities of arm and fingers, i.e. force, reach, lift, etc.