Week 29
Description
This weeks session has seen its ups and downs, first of all the bad parts.. I had another servo that blew up during the testing of the individual mechanisms, this servo could not be replaced via removing it from the robot as it was embedded in a U bracket using milliput. To add to problems, the lip system once again had issues concerning the wire from the lip mechamism rubbing on the brass connectors and snapping under the strength of the micro servos, this is an on going issue with regards to keeping all the mechanisms well oiled and running smoothly.
However both of these issues are now resolved.
Equipment
Metal connectors x 2
Thick Silver Cord x 3
2 mm Heat shrink
Guitar wire
Milliput
To design a new lip system required a lot of thought, the problem is that over time the wire rubs against the holes which it runs through, using thicker or metal wire is not an option as the holes the wires run through in small and angled at 90 degrees. To solve this I added heat shrink to the part of the cord that runs through the holes in the back of the top jaw mechanism. However I did not apply heat the the heat shrink to tighten it onto the cord, instead I tied a knot in each end of the chord that sticks out of the heat shrink with about 3 cm leeway on each side. This allows the cord to run inside the heat shrink whist the heat shrink remains still inside the hole. I also directed the cord towards the eyelet using milliput and a loop made from guitar wire this will also reduce friction on the cord as it passes through the holes to the lip wire mechanisms. I additionally added springs to the brass connectors of the top jaw mechanism to help the lip wire flex back to its original state.
The burnt out servo had to be left where it was embedded inside milliput at the back of the eye mechanism. However I managed to make enough room via scratching at the old milliput with a screwdriver to place a new servo parallel to the old one. I left the back of this servo exposed incase of any problems in the future, making it easier to remove and replace.
This session was also spent testing the durability of all mechanisms, I adjusted the sweeping servo code to initialise different variations in speeds and steps for 20 mins at a time to test each mechanism individually.
The testing proved to be a success with the new rig, however I do not know how long the project will have to run during the final degree show so I may test these systems further and more rigoursly closer to the time of the show. I have also spent a lot of time reflecting back over the past 5 or so months of the project and thinking about how to get the philosophy behind the project across to people because I feel this is just as important as the actual construction of the project. I am putting together a sort of subscript and posing myself questions that people may ask about the project and trying to think about how to get information across clearly, I may also write a short research paper to re-affirm some of these ideologies.
Feelings
I am feeling optimistic at the moment at the start of the week everything went wrong and I felt like giving up however leaving it a couple of days and then going back to the project and fixing the broken elements has helped me get back into the flow of things.
Evaluation
This session was a mixed bag, it started of terribly and ended feeling like I might just have enough time to finish everything and have it running smoothly. However I am still having issues with the Kinect tracking. I tried to install a 360 degree servo into the base unit this was a massive mistake as the numerical values from the kinect meant that the servo spun out of control and took everything with it. i have ordered a new servo with a higher reaction rate and will fit that as soon as it arrives, if it does not arrive in time of uni this week I will have to fit the old mg996r servo and hope it dosnt glitch to much with the weight of the robot. I also purchased a kinect sensor magnifier which I was hoping would reduce the size of the space the robot would need to function efficiently in, however this did not work as effectively as I had hoped as it messed up the numerical data coming out of the kinect...so the unit is useless for this project.
Analysis
The current situation of the project is kind of hit and miss at the start of the week everything was in disarray.. however, I now feel that i am starting to get a grip on the project once more. I also think that this has taught me a lot about how durable the mechanisms are and how quickly I may be able to fix them if anything goes wrong in the future. I have also ordered some additional parts such as 2 more Arduino boards and spare servos and wire and power supplies basically everything that cannot be changed by myself or at short notice. This is to ensure that if anything brakes during the final year show or when I travel to Uni I have back-ups and do not have to end the sessions there and wait for replacement equipment to arrive. (1.1-5)
Conclusion
In conclusion I am feeling optimistic about how things are going at the moment. I am looking forward to getting back to uni this week and hopefully getting some time with my tutor and working on getting the kinect working smoothly. I am also pleased with how the new mechanisms are working and I think they are a massive improvement on the old systems however as with all projects only time will test the durability of the mechanisms. I will keep oiling all the metal rods to keep them from rubbing against the aluminium threads causing friction and eventually stopping or burning out the servos. This procedure will have to become part of my practise from now on as I cannot afford anymore mishaps.
Action Plan
The action plan for the next session is to get all the elements working in harmony and think about how the project will be placed within the finial degree show setting. Taking the advice of my lecturer I will also be thinking about who I would like to see the project and what environment to place it into. I also thought about setting it up in the house when the build is finished and inviting some friends around to test the project and see their reactions and ask if there is any areas that could be improved or did not come across clearly.
1.1
1.2
1.3
1.4
1.5
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