At the beginning of this month Era and Yll had a duty to finish a road with different obstacles, where it would go into work to see how our prototypes will climb into those trackway obstacles. The trackway is made of wood material and the obstacles other than wood are made of stone and with soil. Excpect wood, soil and stone for the construction of the trackway we have also used bolts and wood glue, which are used for joining wood with obstacles. A bark is 1m long and 40cm wide so the whole trackway is 6m long and 40cm wide. Trackway has six obstacles with different heights and shapes. Every obstacle has its own difficulty.The first obstacle is made of two 40 cm long wood, with a width of 15 cm and a height of 4 cm (two parts 8cm). The two pieces of wood are placed one above the other and are attached to wood glue. Has a lower height and therefore is set as the first obstacle, so this obstacle the prototype can pass smoothly. The second obstacle is made of three wooden parts which are placed one on top of the other in the form of stairs. The length and width of the wooden parts are the same as the parts of the first obstacle, while the height of one piece of wood is 5 cm ( three pieces of wood 15cm). The three pieces of wood are attached with bolt. It is a stumbling block that is more difficult than the first obstacle because the wheel has less support surfaces to pass, so one wheel passes to the first part and the second wheel in the second part and so on. Third obstacle is made of stones of different sizes and shapes. The stones are glued to wood with wood glue. Stones since they do not have the same size and shape create turmoil (swinging) during the passage of the prototype into it, so the reason why stones are used as a barrier is to see how a prototype can withstand this swing. Fourth obstacle is made of soil we have placed in a wooden box. Soil we thought it was wet and soft to see how powerful the engines are when passing the prototype to this obstacle. Fifth obstacle is made of very small stones and sand. Even by this obstacle we have thought to test engines and whegs, which is almost like a obsatcle the same as before but only that it is not as soft as the soil. The last obstacle is not like other obstacles. The obstacle is raised by the earth through three softwood that keep it up. The last obstacle we have thought of so for the reason that to see how our prototype will climb to a higher altitude since we have been testing prototype on low surfaces. Also to see how the wheels will react during ascending and descending and to see if the wheels need something sticky to cling to obstacle.
After finishing the trackway we started to work with the designs. First we started with the design of a new base. The base is supposed to be designed in this way for the reason that, as appropriate to the prototype and that it is possible for all electronics to be placed inside the base. As seen from the base there are two parts extracted from the edges of two surfaces which are made for engines, like a motor holders. Motor holders have several holes that serve that part to connect to the engine and so the engine will be held in those parts. The slim part of the engine which serves to rotate the wheel will enter the largest circle while the smaller circles serve to connect the engine to the carrier by the M3 bolt. Also to the base it can be seen that the inner part of the base is below and there are four ‘walls’ of not too large which surround it. The reason why the inner part is below is that the electronics part in the prototype be more stable and secure. The inner part also has some small circles that are open to the entire surface that serve for the easier and better connection of the electronic parts between them. The dimensions of this base are: the whole base 18.5×13.5cm, extrude 2cm, four ‘walls’ that surround the lower part 17x11cm and the height of the ‘walls’ 1cm. Small holes 0.34cm, big hole 0.8cm and motor holders 4x3cm, extrude 0.5. After 3D design of the base we saw that the base have some problems. The biggest problem was the big weight of the base, while the other problem was the motor holders that were thin and immediately broke because the weight of the engines was much heavier and needed more support for the engine, where these holders did not. So we decided that the motor holdres will be new and will be stronger and more durable.
The next design was the motor holders. The type of engines we used is Nema17 and so these holders are adapted with engines. Since the engines have the shape of the foursquare then even the holders have approximately the same shape as the engines. The holder has three parts needed to attach the engine with the holder also with the engines. The part that has four holes needed that the slim part of the engine as seen in the third photo is inserted into the big hole where it will be connected to the engine, and to put together motor holders and motor through the small holes and bolts. The lower part of the cover which has three holes connects with the base and so the base with the motor holders join one another throught the bolts. The dimensions of this motor holder are: the part which has four holes 5,5×4,5, big hole 2,3cm and small holes 0,5cm, the part that connects with the base 3x5cm and holes 0,5cm and small triangle 3x3x3,5cm.
This is our wheg we’ve used for the prototype this month. This wheg has five wings which have two parts: the arc part and the vertical part. We thought the wheel have five wings for some reason which are: prototype to be more stable, be more secure when climbing to a certain height, that during the movement of the robot he would not create turmoil so when a wings touches the other side of the contact surface, the other wing is close and does not allow space to remain when crossing one arm to the other. Also another reason why the wheg is designed in this form is that to have greater frustration with the surfaces to pass and prototype to be easier to overcome the obstacles.
After 3d design of the base that we do not use for prototype due to weight and some other minor problems, we thought that the base of the prototype would be wood. By the lasercut we pressed a piece of wood with the length we needed and then we continued to put the motors on the base and other electronic parts. This prototype was a from of test in the electronic part. We’ve used 4 NEMA 17 motors. These are stepper motors and they are used everytime when there is a need for precision and power. NEMA 17 motors are commonly used in 3D printers and CNC machines. Why did we use them? We used them for their precision and power, but they were not the right type of motors to be used for our project. Despite their upsides, they also had downsides. NEMA 17 motors weighted alot and needed a lot of current to run so this equals to more batteries and extra not needed weight. Motors were connected to an Arduino Uno through stepper motor drive controller board module L298N.
This is our prototype of January.