The Custom Made: යකඩයා - 3D Printed Tracked Robot

With the collaboration of 5 members, we developed this tracked robot which called as "Yakadaya" for the competition of Uva Wellassa University robotic competition. How ever we were not able to get the trophy. But I think it is worthy to tell you how we built it.

The idea was came from one of our team members to build a tracked vehicle instead of using wheels in order to get more traction with the ground. Here is the link which we got the basic knowledge on how to build the track. Special thanks goes to "http://www.rctankcombat.com" for sharing the knowledge.

Making the Track

Among various types of track system, we selected hinge track system for Yakadaya. There were several reasons for the selection. According to the game rules, the robot should not exceed the dimensions of 30cm*30cm and 5kg of weight. So the cheapest and best method was to use door hinges for the track.

Parts List

1. Door hinges

2. M3 X 300 nuts and bolts
3. M3 X 80 nuts and bolts

4. Rubber sheets with texture on one face

5. Adhesive

Connect each hinge using rivets. We connect each hinge to other by using two rivets as you can see from figure 1.

Figure 1
Door hinges

The middle screw should be about 8mm long. Otherwise it will jam with the engage pins at the drive wheel. Due to the short size of the middle screw, it tends to derail from the drive wheel. You must calculate the distance between engage pins at the drive wheel. As per our calculations, we add ed 9 engage pins at the drive wheel. Figure 2 and 3 shows the solidowkrs design and 3D printed drive wheels.

Figure - 2
Drive wheel ( Solidworks Design )

Figure - 3
3D printed wheel with engage pins

We added four supporting wheels. Those wheels carry out the total weight of the robot. It is better if the number of supporting wheels can be increased which will add more traction with the ground floor. We decide the size of the supporting wheels arbitrary to fit within 30cm width according to the game rules. figure 4 shows the supporting wheel.

Figure - 4
Supporting wheel

To reduce the rotational friction and to support axial load, it used bearings between the supporting wheel and the axle. As in many tanks a 3D printed T shaped bar was used to mount supporting wheel axles.

After assembling the setup, there was a considerable amount of slack between the track and the driving wheels. To reduce the slack we had to add additional two supporting wheels to the other side as well. figure 5,6 and 7 shows upper side supporting wheel and the T shaped bars.