How do you detect a cross-section and move from following the main line to following the crossing line. In this series of video tutorials we are starting with a very simple solution that could work in most of the cases. It is especially useful for the FIRST LEGO League Trash Trek competition where there is such a section.
Tasks on using the LEGO EV3 Mindstorms Color sensor. Quite fun and useful for different STEM classes or just to get to know the sensor.
This is the oldest and most classic problem in the field of robotics. Shaft in an opening. Basically robotics and in improvement of many of the actuators is about improving the solutions to such problems. Let's see how we ca do this using a mission model from the FIRST LEGO League (FLL) competition.
We are describing the Warm gear in this video. This worm gear does most of the magic of controlling how the different gear wheels move on the different axles.
The integral part "remembers" the errors that the robot has made in the past and we can compensate for those errors. This will make the robot return back to the line that we would like to keep it aligned.
It's inevitable. While following this gapped line we would reach a gap. The robot must somehow understand that there is a gap and must make a decision on what to do. For detecting the gap we use the Rotation Sensor. Not the most popular, but very convenient in many cases. Check out the video.
We should multiply the error by a certain number and then add it to the steering of the LEGO Mindstorms Steering block. In this way, by changing the coefficient we change how much/fast should the proportional part influence the steering of the robot.
In this video tutorial, we would do a few experiments with the coefficients for the Integral compensation. There are actually two coefficients - "c" and "b"
This time we stop on "Using the Right Senses" mission, or actually on how to solve the "Right Senses" mission without "Senses" (sensors). To achieve that we use the carabineer counstructed in one of the previous tutorials, of course after a small modification.
Follow an object using the LEGO Mindstorms Ultrasonic Sensor. Object moves away, the robot moves with the object. The program is very useful if you are doing STEM classes and you want to demonstrate results. People react very well to a robot following you like a dog for example.
In this third video we show some of the tricks in building this Multi-axles mechanism. Things you could learn from an use in your next constructions.
In the previous part of the video lesson we showed how imprecise a chain LEGO Mindstorms robot could be if its positioning does not rely on sensors, but only on the use of move block. In this tutorial we will show the same thing, but using robot on tires.
Have you even tried to move the robot not in rotations or degrees or seconds, but in metres. In this episode I am building a new block that could be used to move the robot a specific number of millimetres (mm). You could directly download and use it in your programs.
The previous rubber bands video showed a way to trigger the rubber band without a motor. This video gives one more idea on how to lift an axle and in this way release the rubber band. Use the idea for you LEGO Mindstorms robot constructions.
Stop on detecting an object with the Ultrasonic sensor and move after detecting there is no object. Join of the previous two video tutorials in one
Using a number of axles, beams and rubber bands we collect many loops at once. This is an important part of every competition, mostly of the FIRST LEGO League.
There are many loops in the FIRST LEGO League competition. In this video we collect some of them by following the idea of the ELM team.
Many FLL competitions have a mission for demolition. You should always destroy something, but destroy it in a regulated manner and probably collect the destroyed mission model after that.
We keep the robot orientation straight while moving, but when we stop the robot could be in a different orientation. This applies for both using the Mindstorms Gyro Sensor when moving straight or the Mindstorms Color sensor when following a line. In this video tutorial, we will do a few examples of when an how this could happen.
This is the final run for our World Robotics Olympiad (WRO) 2015 Elementary Challenge Robot. In "dives", detects the color of the pearl and then counts the number of Ping-Pong balls to release.
You can collect the car for scrap or repair it. The ELM teams decide to repair it. This requires them to place the engine in the car and it's very interesting to think about this problem.
We've detected the gap. It's time to move over it. This is difficult because we have to detect where the line is after the 0.1 meters gap on the line following field.
In the first LEGO tutorial we started following a wall with the Ultrasonic Sensor. In this tutorial we would improve the program, remove the zig zag movement and make it very smooth.
Based on your feedback we have decided to show you the live process of building a complex LEGO Mindstorms Competition robot without having the whole robot ready yet. We would be making mistakes, showing them and taking up the challenges right in front of your eyes. The first construction would not be perfect but we would eventually arive at it.
"What is the light in the room?" - should it even matter. You can use one program for all lighting conditions by calibrating the color/light sensor of the LEGO Mindstorms EV3/NXT robots.
Tasks for school STEM classes or home exersie. Try to solve them to submit your solutions below.
In this tutorial of the series we would get into more details on how the flywheel works, what's its purpose and how the whole attachment is triggered with the first rubber band.