Proportional Line Following with EV3 Mindstorms. Part 2
Continuing with the Proportional algorithm for following lines. Smooth and stable this is the first part of the PID.
- #176
- 01 Nov 2015
Continuing with the Proportional algorithm for following lines. Smooth and stable this is the first part of the PID.
Rubber bands in the LEGO Mindstorms sets are very handy when it comes to collecting objects, especially loops. The mechanism most of the time could work like this - an axle is pushed, a rubber band is released and a lever collects the loop.
Last part of the series. The final touch of the program makes sure that it works and is following the line with the LEGO Mindstorms EV3 Color Sensor in a smooth and fast way.
The third robot has the brick and motors placed vertically. This is quite unusual and difficult, but the construction is very powerful because it saves space.
In Episode 58 we introduced you to a LEGO Mindstorms EV3 Modular robot. In this tutorial, we show you how we reached that construction. We start from a construction found on the Internet and take you through the process of examining and improving it, till we reach a more stable and reliable robot.
Second active pinless attachment for the robot construction. It is placed in the top/right corner of the robot and includes an interesting gear system for transferring the power. The attachment is suitable for complete rotations.
This is a third example for adding an active attachment. This third attachment is now connected to the wheel at the front of the robot. Again, the attachment could be easily extended.
In Episode 58 we introduced you to an LEGO Mindstorms EV3 Modular robot. Mic Lowne wrote to us and had that robot remade, because it used too many blue lego pins and could not be build using one EV3 kit.
This is a very interesting idea that is worth sharing with the rest of the teams and the ELM team has provided it to us. Check out how they drop a LEGO human at a specific place.
The last fifth construction is larger compared to the previous constructions. It is wider. It has four sensors and you can take a larger load all by keeping the robot stable.
Need to transfer circular into a linear motion. You need a rack. Here is an attachment with a rack for our box robot.
We start a course for following a line with crosses and gaps. This is a challenge that one of the users at FLLCasts.com was trying to accomplish and asked us for advice. We present the whole challenge to you step-by-step. But first, let's also see the whole run of the line following algorithm. With this course, we also do an introduction of using State Machine as a programming pattern.
The attachment builds on previous episodes this time using two LEGO rubber bands. When a lever is released the rubber band exerts pressure on it and moves it in a circular motion. As an example we are solving the 2012 FIRST LEGO League, Senior Solutions, stove mission (which was quite interesting as a mission)
This is one of the very interesting attachments by the ELM team. It is using rubber bands and some rubber to precisely drop the chicken. Very interesting way. Check it out and try to learn from it.
Based on feedback from many of you in this episode I would like to show you how to build an active attachment that changes the orientation of a gear wheel placed vertically to a gear wheel placed horizontally. This attachment could be used in competitions and shows a basic principle of changing the orientation. All attachments could follow the same principle.
In this video lesson I am building a LEGO Mindstorms EV3 active attachment powered by a small gear wheel. The attachment could move up and down, it is very useful for collecting objects. It could easily be adapted and used on other robots.
We are making a parallel with Video Lesson 56 from the series and we are also showing ways to improve the stability of an axle which is most of the time neglected, but could lead to great problems.
This robot could quite possibly be build from a single EV3 core and EV3 resource sets. It uses fewer parts and only three motors. There are additional parts that could be skipped when building the robot and we have added these parts only as to make the construction more complete.
In this Episode, we stop at the pinless attachments for the Box Robot 2 and especially for the constructing a frame. This frame is then used for further extending the robot with attachments.
This video tutorial contains the final 2 programs for moving straight with a LEGO Mindstorms EV3 robot. The first program is for proportional compensation that just keeps the robot orientation straight, while the second program is for Integral compensation that returns the robot to the straight line when the robot makes a mistake.
We extract the Proportional Line Following algorithm into a new block with parameters. This allows us to experiment with the Threshold, Constant Speed and Relaxation Coefficient. You can now easily use the block in you other programs without having to implement it.
In this lesson I would like to show you how to build a LEGO Mindstorms competition robot and tell you how we have designed the construction used in the videos so far. Surely it isn’t perfect, but it is a good start.
In a competition environment like the FIRST LEGO League (FLL) or World Robotics Olympiad (WRO) the color sensor is more than useful. It makes positioning on the field quite easy and precise.
Looking at the field we must first think of a strategy of solving this line following problem. There are rules that the robot must follow and these rules should be programmed in the robot.
The robot uses one middle motor. This middle motor with the use of a few gear systems controls for different axsels. We have attached wheels on this axles so it is very easy to extend the robot construction for additional LEGO Mindstorms active attachments
How do you lift heavy objects with an attachment? In this episode we show a simple, interesting, but yet not very popular way to lift something heavy with and LEGO Mindstorms EV3 robot and without gears and motors as attachment. As a specific example we are using the Strength Exercise mission from the FIRST LEGO League 2012 competition.
Positioning your MINDSTORM robot precisely on the FIRST LEGO League competition field is one of the first things you should learn while preparing. In this video tutorial, we will show three different attachments you could use when aligning to the walls of the competition table. We will show other ways and attachments in some of the next videos.
The robot attachment build in this tutorial gives an idea on how to release a rubber band at a specific moment using a motor. It's a simple, but yet powerful technique on using rubber bands.