April the month of testing whegs and trackway.
The month of April has been a month with more testings and proof in whegs and trackway.
So our ideas and creativity were never missing.
This is a first wheg that we have designet during this month.
The shape of the wheg has been made for some different reasons. Some of reasons are:
1.At the moment the prototype climbs to a certain height there will be support and curvature to have easier climbing.
2.To have the greatest friction between the wheel and the surface.
3. To not slide and to be easier to climb.
The second test was designing a part of wheel with negativ extruded pyramids and designing a small trackway also with negativ extruded pyramids that fit the wheel. Negativ extrude pyramids of the wheel and trackway have the same shape and size, so they match each other. This has been done to see how negativ extrude pyramids the wheel and the trackway will match and is it more difficult for the prototype to stick to the surface if the wheel and the trackwheel have it negativ extrude pyramids or if they do not. We have seen that this method is working, so we’ve decided that the wheel and the trackway have negative extrude pyramids.
This is our third test.
This design also has negative extruded pyramids on the contact surface. Each negative extruded pyramid is the same and left the same with each other. The idea of why we have used this form of negativ extrude pyramids is that they allow support of the robot with the surface and that the risk of them being broken or remaining on the surface is small. The second part of the arm is slightly curved to allow easier transition from arm to arm during movement. The second part of the arm is slightly curved to allow easier transition from arm to arm during movement. Other modifications that the wheels have encountered in general is the implementation of a system that smoothes shocks during the movement of the robot. This is a simple system that when leaving a space at the start of the wheel arm, this causes the wings of the robot to bend during the movement. The wheg also has a wheg connection system with the engine we are using. The system has three holes where one enters the engine shaft, to the other comes the bulb of the size M3 and in the last hole enters the strut that is reinforced for the engine shaft by strengthening it. The whole system is extruded for 10mm from the wheg design and can be easily observed. The type of engines we are using are DC geared motors. The axes of these engines are flat on the one hand, and this enables this system to be efficient. This wheg design also had some problems. The length of the thorns was very short and the robot continued to slide from the trackway (the moving surface). During the transition from one side to the other, point A to the wheg was in contact with the surface and given its shape it did not provide support for the wheg and the robot as a whole, so the robot slipped during its movement.
One of the ways to create a trackway was through machining. This was accomplished through the CNC machine by carved wood. The wood is carved in order to fit the wheg. We used two types of wood for experimentation with them. The wood we used are MDF and beech. MDF we did not do too much work for the reason that during wood carving the wood lost its shape whereas the beech was stronger and better in processing, allowing us to maneuver how we wanted with it. The thicknes of the first wood is 80 mm and ‘Frezi’ is 4mm. The thicknes of the second wood is 50 mm amd the ‘Frezi’ is 4mm.
Our fourth test.
During the trackway realization we worked on the wheels in order to negativ extrude pyramids to fit with trackway. We designed this in the inventor with this specifications: thicknes of wheel 10mm and length of pyramids 3mm. The corner of the last pyramid in the wheel was the corner 90 degree. The reason why the last wheel pyramids were 90 degrees was to fit the best with the trackway engraving. The reason why the wheel is made of three arches is due to the most appropriate shape when the wheels move to the sloping surface.
The idea of creating a tail came when we had obstacles on crossing through different terrains with our whegs when they changed directions so we thought that a tail would help us go through these surfaces.
The tail is designed on AutoDesk Inventor, we had also different ideas on what shape and size our tail would have so we got two main options on implementing it:
- The tail would move upside-down
- The tail would move left-right direction.
We picked the second idea because it was more reasonable because when the robot changed it’s direction it would help us to sustain the robot’s balance. (left to right)
Until now we’ve been working with different passive tails, which had simpler designs and ideas of implementing. So we chose to increase the level of difficulty by creating something more complex.
The tail has dimensions of 10×2.8 cm.
During it’s designing phase we decided with no specific reason to create a 3.3 mm hole at the very end of it’s finished base by thinking that it would help us on better performing.
The tail had an extra part that helped the robot to stay sustainable. It was a square piece 2.8×2.8 cm that had in it’s diagonal 2 holes to climb on the rotative part of it’s servo.
In the second picture there are some holes for 3mm bolts and in it’s corners of the diagonals.
The active tail happened because of it’s electronic connections between servo motor and Arduino UNO.
The tail was 3D printed with Bronx PLA.
It can be seen clearly and in another picture that except the servo motor we added another piece with rectangular shape and it stood perfectly on it’s position with the base.
The tasks was finished perfectly but what we can improve is the creation of a surface with more smooth surface.
Here we show the evidence that we made the prototype to walk in the most accurate way.