Video tutorials -

• EV3-G

The robot can move with different speed by applying different power to the motors. It will most of the time make smaller deviations when it moves slower. But you can't just move with a power of 10 all the time. This is a way too slow especially for competitions like FIRST LEGO League or World Robot Olympiad. In this video tutorial I would like to discuss the balance between motor power and robot movement error, how does the battery influence the power of the robot and to conduct an EV3-G experiment that will record the values of the Gyro Sensor along with the current power. 

The EV3 Gyro sensor is quite powerful, but there are some little tricks when using it. In the previous episode we showed a hardware solution to the problem and now we are exploring how could the sensor be calibrated from the EV3-G software. Thanks to Sharon and Faye (full names omitted) for the request for this video.

The Gyro sensor in LEGO Mindstorms EV3 sets is new for the sets and we answer basic questions about its usage. The sensor detect when the whole constructions turns at a particular angle, but there are a number of gotchas in using it.

Tasks for the Gyro sensor that you can use in STEM classes, while preparing for a competition or just to explore how the sensor works.

Turning with the Gyro Sensor on a specified angle and stopping there have never been easy. It is not going to get any better. However, this is not a problem of the Gyro sensor. The problem is in the way we develop our programs.

Let's explain the problem of just waiting for the Gyro sensor to detect an angle and think of why the robotics systems work like that.

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. 

This video tutorial reviews the EV3 Gyro Sensor and the HiTechnic Gyro Sensor for the LEGO Mindstorms NXT robotics Kit. We compare the two sensors and demonstrate them in action.

This is where the confusion really comes. We are keeping the robot orientation straight while the robot moves, but at the end the, robot is not at the fiinal location that we would like it to be. The robot is still about 2-3 centimeters away after moving for about a meter.

The first part of making the robot move straight is to keep it oriented straight. While it moves it could make an error and turn slightly to the right and then the program should turn in back to the left to make its orientation straight. In this video tutorial, we would discuss how to implement a program to keep the robot orientation straight even when we are pushing or pulling it to either side and in the same time it has different wheels.

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. 

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"

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.

Let's record the values of the Gyro Sensor while the robot is moving and is trying to keep its orientation straight. This is an interesting experiment and we will have to use file access to write the values to a file. 

Showing the same run, but from a different angle. This allows you to see more of the way we sensors work and how exactly the robot positions itself.

This video tutorial is about understanding the "magic". In this video tutorial, we would conduct an experiment and will look at how exactly does the integral part of the PID algorithm compensate for the error that the LEGO Mindstorms EV3 robot makes.