The robot has 2 swinging arms attached to the main chassis of the robot. The swinging arms each has one or more rotating tires attached to them for gripping & climbing the poles. A simple hook mechanism is attached at the end of the swinging arms to push the ping pong ball into the basket.
- 1 motor for moving the robot front and back with no turning ability. (since that's all you need to move from pole A to pole B)
- 1 motor for swinging the arms to the front to hold on to pole A and swinging to the back to hold on to pole B.
- 1 motor for the rotating tires on the swinging arms for climbing the poles.
I did not include the sensors in my sketch but you may use a Touch Sensor on each side for detecting when your robot has bump into a pole, or you may use an Ultrasonic Sensor if you want a non-contact option. You may use another Ultrasonic sensor for detecting when your robot has reach the top, or you can use light sensors to detect the different sections on the poles but remember the colour of wrappings on the poles are random, so you've been warned here. On the way down, you may use a third Touch Sensor to detect when your robot has reached the ground. As for moving from pole A to pole B, no sensors will be required since your robot can only move straight.
If you are daring enough, you may even choose not to use any sensors and rely solely on rotation alone but i wouldn't recommend it unless you are pretty confident with your design.
the program for this robot should be very straight forward, maybe something like:
- move straight until touch sensor 1 bump into pole A
- climb pole A until ultrasonic sensor 1 can no longer "see" the pole
- climb down until touch sensor 3 hits the ground
- whole robot reverse until touch sensor 2 bump into pole B
- repeat step 2 & 3.
Please bear in mind that this is just one of the many possible ways of solving the challenge. But my message here is always put your ideas into sketches & drawings using simple shapes and then list down the tasks your robot needs to complete, the constraints/limitations of your design, before you actually build the real thing out. Too often the students tend to dive straight into building the robot without having the big picture and eventually they get stuck very quickly.
So i hope this post helps to give you some idea on how to conquer the vertical limit challenge & also how to tackle a complicated problem in a simple way - put your ideas on paper first (^_^)