Introduction to Robotics Experience

In our robotics class this year, we did various activities that includes constructing robot and programming the NXT. Not only do we have to know how to place gears and beams together neatly, we also have to apply math and physics in order to maximize the function of the robot. This proves to be an intellectually engaging activity as we have to really apply what we have learned. One example of knowledge that I have learn during this class is the gear ratio, where changing it will vary the speed of the robot. I find it extremely interesting to learn as this knowledge is widely used in real life technology such as car industry and machinary.
Of course, this course also encourages us to collaborate with our partners during investigation. When we encountered any problem, we have to discuss as to what have went wrong. This is very educational because it helps us to learn the skill in collaboration. Overall, a class that really provides student with fundamental understanding of the robot and instill essential practical skill in the students.

Challenge: Drag Race

In this challenge, speed of the robot is an important factor of the race.
Therefore, we need to decrease the gear ratio in order to increase the speed. This means that it is necessary to connect bigger wheel to the driving wheel and the smaller wheel to the driven wheel. This way, the robot should be capable of running at an incredible speed.

Challenge: Tractor Pull

In this challenge, power of the robot is an important factor of the race. What we really need to is to increase the gear ratio in order to increase the power. This means that it is necessary to connect smaller wheel to the driving wheel and the bigger wheel to the driven wheel. This way, the robot should be capable of pulling heavier object.

Playing with Gears (Chapter 2 summary)

Chapter 2 in the LEGO MINDSTORM text book deals with the usage of gears and the technique in building it. This summary will explore some of the useful gears and how they function. The first gear is the bevel gear. The design on the edge of this device allows the motion to be transferred perpendicularly to another gear. This is useful when the construction of the robot does not support parallel transfer of motion.

Another gear that has specialized function is the clutch gear. If you experiment the gear by placing it in a robot and rotate it, you will notice that this gear offers some resistance at first then it will turn. This resistance is the very essence to the purpose of this wheel, because it decrease the force exerted on the system when the motion comes to a stop. This way it will prevent the system from damaging itself.

Finally, there is the pulley system. Under some circumstances, it is better to use the pulley system than the gears. For example, when you want to transfer the motion between two wheel that is widely separated you can use the pulley system. This is better than placing many gears in between the wheel since pulley system requires less power to start the motion. In addition, it produces less noise than using gears. The only downside is that the pulley does not transfer high torque since the belts tend to slip.

Here is an example of a pulley system:

Get in Gear (Investigation Summary)

As we have explored, the ration between the driving wheel and driven wheel is very important to the speed of the robot. Here is what will happen if we change the gear ratio:

If the driving wheel is bigger than the driven wheel, the robot will move faster since 1 rotation of the motor corresponds to more rotations on the driven wheel.

In contrary, if the driving wheel is smaller than the driven wheel, then the robot will have a slower speed. This is because 1 rotation of the motor will cause the driven wheel to rotate less.

The principle of physics behind the cause of this phenomenon is something called torque. We increase the torque of the robot by reducing some power. As torque is directly proportional to the displacement of an object, increase in torque will result in an increase in displacement.

Obstacle Course Results/Conclusion

After spending more than 20 hours of hard-work accompanied by tears and sweats, our robot had finally completed the race course perfectly. The robot is not only capable of maneuvering through the course; it is also able to detect any object in its way and attempt to avoid it. What is special about this program is that it can avoid any number of obstacles as the program is set in loop. In addition, the sensor is able to turn and sense whether the direction it is trying to maneuver for obstacle avoidance have other blockage. If it does detect an obstacle, it is capable to turn in the other direction. In a sense, it is a form of artificial intelligence as it is able to decide on which direction it should turn to avoid the can. The program itself is rather complex, consist of multiple loop blocks, motor blocks, sensor blocks, and logic blocks that require multiple wirings. Overall, I believe my partner and I are extremely satisfied with out end-product.

Classic Projects (Chapter 14)

This chapter deals primarily with the classic built of LEGO NXT robot. Although the techniques can be unexciting for people who want to build some awesome walking anthropomorphic robot, they are still useful. One technique is to use an ultrasonic sensor to detect an edge. By placing the sensor towards the ground level, it will allow robot to detect an edge as there is a change in distance between the sensor and the surface of he floor. Another technique is to build a steering assembly, which consists of mainly the caster wheel and the ability for it to rotate. The main function for this assembly is, as the name suggested, allowing the robot to turn. By allowing the robot to turn, it unlocks multiple functions, such as line tracking and obstacle detection. Of course, that will also require the placement of ultrasonic sensor and light sensor in order for the robot to function properly. Overall, the classic technique in building the robot plays an essential role in allowing it to perform versatile and diverse functions.