Aim:
To study the basic aspects of machine design
For this week we had a task of designing a machine, in so as we would be capable to move the joints manually...
The most exciting part this week was that it was entirely a group project that actually proved to be a load of fun.
Hence considering the task we had set up a page on the website of the lab, that guides well through the procedre we followed, along with the aspects we learnt.
Other than that following are the thigs I was put to explore and the things that I had did
Learing outcomes.
This week I was initially planning to work with the interfacing that would be required to run the machine, but the initial thing to be considered was the design aspect about how the machine would actually stand.
For the same we had following things to care about..
- The weight calculation for each of the part or member we chose.
- The torque calculations for each of the drive we desired to added.
- The maximum distace that we could achieve considering the above two factors.
Following pages gives a tour about the things I learnt:-
- The calculations part:-
As listed we had the basic calculations of finding the torque at each joint of the arm. For this we had initially made the calculations on a board, where our Rohan Sir had guided us to exactly plot the points and formulas needed.
After this we made an exel sheet where we added all the formulas along with the data that could help us do all the calculations in a jiffy,
This bacame very easy when eventually we were forced to alter the dimensions as per needed, in this process I learnt a parametirc way of calculations, when we do designs on the paper. - The next thing I got into learing was the design considerations that were to be mae when we make any machine.
Those were a few when we actually had sat for the calculations and one of my colleague, Rohan was explaining us the things to be considered. Few of them are listed as here:-- The power that is actually needed to drive the machine
- The bending moments of the materials, to find that what strength each member could hold.
- The involuntary forces that could be acting on the machine as it moves.
- The effect of changing loads could have on the driving forces.
- Along with these mechanical mechanical properties I got to study the requirements of the electronic componenets too.
Thigs I got opportunity to work with:-
There were a few things I got into working with,
Initially I wanted to work in the interfacing team, to see how the machines would function, and I had also begined with the same, attempts listed here.
But after a point I was working with the team dedicated to design the structure.
Here I was working with the strutural designs where the calculations were being sketched by my colleagues.
For the same here were our attempts listed, that we had designed.
- The initial one:-
Initially this was designed just to calculate the range and to find out what sector we actually could get as the area of work.
-
The MDF Attempt:-
Then after the a few calculations we had designed this arm to test the mecanisms, in between of which we had manufactured the MeArm just to figure out the linkage mechanism used, after which we had designed an arm for which we tested all the joints for basic movements.
This was the basic design to test the how the joints and the linkages would work, and how were we suppose to do the allignment of the end effector. Out of this we had a few conslusion, as stated below.
Conclusion:-
- The alignment of the joints had to be perfect considering the semetry and the Centre of Gravity of the arm, this was because we notived certain amout of stresses on the joints of the arm
- Also for this arm we had made the studs(projections that would go into the bearing) of our own, this had became a problem where we realised the need for few industrial grade components.
- After this we had tried attaching the motor at the end effector, that resulted into bucklig of a few joints and member that played a great role in assigning the position of the end effector.
- The Final Show:-
After a lot of brain storming and calculations we were up with the final designs, where I had tried to build up an alignment of the joints and considering the center of gravity.
After which I sat to make the cad files of each inorder too get a rouch idea of the assembly, becasuse we had planned to get this manufactured in acrylic itself as our final product.
Hence this was the final assembly that we had got..
This time we had resolved the issues we had faced in the attempt previously..those included- Changing the pressfit components into more of mounting components, haveing options for bolting
- Aligning the motor for the end effector in the center that resulted in the nearly perfect weight balance
- Fixing the normal studs with the once machined using cnc turning centers.For which I had tried to write the G-codes, this time mannualy, because the machine that we had in our contact had baic tools that were difficult to feed to the machine, hence we had to write it manually
- Also this time we went into manufacturing of a pedestal for a motor, this we planned to make it bit heavy for obvious reasons, hence i had attempted a design of this and had fabricated it in mild steel sheets.
After a few regorus attempts of improvisations this was the final structure that had taken the live form, it actually felt great to see that the centre of gravity had been balanced, without the holding torque of the motor.
THis was probably the things we had pulled out in the initial week of machine, which I was directly involved into.
Rest a few if things I had learnt in the programming too, that could be found here.