Introduction to Robotics experience

This robotics class was really interesting. I even enjoyed doing homework. From the experience I have been in this class, constructing robot is very significant. This is because it's linked to every aspect of both science and math. For instance, if the robot has bigger wheels in circumference, it can move further than the one has smaller wheels with a same number of rotations. Programming the NXT is important too. Although the robot is well constructed for a certain situation, if programming is wrong, the robot won't work effectively. For example, we need to be very careful of making the program related to a sound sesnor. We should make two wait blocks to avoid two actions to simultaneously happen. Finally, utilizing every sensor is also pivotal. Without using sensors, we can't apply the robot to many situations. For example, without any sensors, what the robot can do is just moving as soon as it starts to run. Nevertheless, with a light sensor for instance, we can track a line with a specific color.

This class teached me a lot of scientific and mathmatic asepcts as I read the robotics book. With basic knowledges I gained by reading the book, I could effectively not only program NXT but also construct the robot. Then I could check if my applying was right by running the robot. Furthermore, this class required me to communicate and collaborate with people. Because this class was lacking the robots and books in number, it was very important to discuss with people and come up with a good plan. Also while doing some challenges, I needed to share the ideas well.

Tractor Pull - Test of Strength

This challenge is to construct a robot that will push or pull the most weight 50 cm in the fastest time. Since we are considering both of the strength and the time, it's very important to find out the gear ratio which torque and angular velocity are well balanced. If the torque is too high, then the robot won't be able to push the weight quickly. In contrast, if the angular velocity is too high, then the robot won't be able to push the weight effectively. It may not even push the weight. I really wonder which group will find the best gear ratio. In my opinion, this time, small gears won't work.

Today, the combination of the smallet gear and the biggest one, which made the gear ratio 5 was the most effective to pull or push the most weight.

Drag Race - Test of Speed

This challenge is to construct a robot that will be the fastest in a 3 meter race. Technically this challenge is a matter of designing a good set of gears. In fact, I saw many groups use the biggest gear on the motor and the smallest one on the wheel. However, very competitive, our group tried to use the combination of 4 gears (2 of the biggest ones and 2 of the smallest ones) Impressively, in the air the wheels rotated crazily. It was like a fan to cool people down. Unfortunately, however, when the robot was on the surface, it didn't even go. Therefore, we modified. This time, we used 2 of the medium size gears and 2 of the smallest ones. However, again, the robot didn't go. Thus, we just used the biggest gear and the smallest one only. I hope it will make a good start. A good start is the only way to be the first, because most robots' speed is the same as mine.

Am I depending on the luck too much ? :)

Gears and Speed (investigation)

To check which Hypothesis is more effective, you measure teeth on a driving gear, teeth on a driven gear and gear ratio. You set the robot to go for only 3 seconds. Then you measure how far the robot goes for 3 times and average the distances. Averaging is important, because it reduces the error created during the experiment. With the average, you get the speed by diving it by time, which is 3 seconds. Having got every data for all conditions and using both of the Hypotheses A and B, you predict speed. After that, you compare the predicted values to the actual value. The Hypothesis which gives you a similar value to the actual one is consequently B. This is simply because the actual value and the predicted one are close. Accodring to my data, for the setting that gave me 49.3cm/s in reality, Hypothesis A gave me 18.1cm/s whereas Hypothesis B 50.3cm/s.

Another aspect we need closely look at is that speed and the gear ratio has a inversely proportional relationship. In other words, if one decreases, the other increases. Also if one increases, the other decreases. According to my data, gear ratio 1 gave me the speed 30.2cm/s. However, gear ratio 3/5 gave me the speed 49.3cm/s