The LEGO Mindstorms EV3 set comes with two LARGE motors. But even though these motors look almost the same they are not quite the same. There are always some differences in their behaviour. If you have more than two motors, because you bought them or you won them somewhere at a competition, it is worth doing an experiment to find which pair of motors works best.
Every time we start the robot we want to start from the same place, not only in terms of where we are on the field but also in terms of how are the motors rotate. The motors have an internal sensor for detecting the rotation. Because of this they know how rotated they are. It is a very good practice to always reset the motors before we start a competition run especially at FIRST LEGO League or World Robot Olympiad competitions
Based on a request we are showing the robot construction with two rear motors instead of a differential. In this way, as a construction, it is closer to more students, but much more challеnging for programing.
Build a similar mechanism to this one. Similar, but for your robot. This is the task for you. Try, give yourself half and hour or even an hour.
This third way of positioning the LEGO Mindstorms EV3 motors on the robot seems to be the most productive with the most advantages. We have named it "correct", but we completely understand there might be other even more efficient ways to position the motors on the robot.
This video tutorial demonstrates the accuracy and consistency of the robot behavior when we use only the blocks for moving the robot without any sensor. Spoiler alert - the robot is not consistent and it is not accurate.
This second way of positioning the LEGO Mindstorms EV3 motors on the robot leaves more space for the Mindstorms brick and for attaching a third motor. We are experimenting and showing the advantages and disadvantages of this particular construction.
We are showing the first way we could position the motors on the robot construction. This seems to be challenging for many robot builders and that's why we are going to do it in a few different ways in the next few video tutorials from the series.
We will demonstrate an alternative way to make the robot move backward
Once you start turning how to do you a whole 180 degrees turn. The robot almost does it, but not completely
This videos tutorials demonstrated the robot accuracy in 10 runs one after the other. 5 of them are with the robot moving slow and 5 are with the robot moving fast. See for your self what is the accuracy achieved only with the move blocks of the robot.
Why we will never use seconds in our lessons.
In this video tutorial we start with the basic of the basic, eg. how to move. We use the block from LEGO Education SPIKE Prime Word Blocks software. It is based on Scratch. The goal of the tutorial is to demonstrate how we can move and to teach something very important - the robot moves inaccurately
Let's move with the VEX EDR robot using its motors, the wheels and some RobotC programming. We devide the program in three parts - Connect the motors, program the controller and turning.
How to control the arm of the push bot using the two triggers on the GamePad of the FTC Push Bot?
The comunication between the motors and the controller should be configured in the RobotC software. Each motor could be connected on a different port and the goal of the video is to show you how.
Conenct the motors of the VEX EDR motor to the VEX Corted Controller. For connecting we need the motor drivers.
Now that we know how to make the robot move forward let's see we can make it move backward.
In this video tutorial we will reach a specific location on the field 10 times. This programs demonstrates the accuracy and consistency of a program that used the Motion Sensor to detect the angle at which the robot rotates. At the end of the tutorial you will have a visual and clear picture of what you could expect from this basic usage in terms of consistency and accuracy. This might be enough for some cases and it might not be enough for others.
With this video tutorial, we start with Turns with the VEX EDR robot.
In the RobotC software we could make the robot wait for a couple of seconds by using the wait function. This will give the motors a chance to work and this will actually move the robot.
In this episode we combine in a single program the previous two programs for moving forward and backward.
We are ready to build the first program for moving the robot forward and backward. We learn how to build simple programs for moving the program. But it is not that easy...downloading to the robot does not always result in the robot moving.
To prepare the robot to move in a square and to use a loop in the program we would first make this VEX EDR robot move forward and turn, using a program developed with RobotC.
Spinning with the VEX EDR robot involves the use of both motors. The left and the right. Every robot with wheels could spin and this makes not exceptions.
Where is the math while turning? Is there any math involved? Should there be?
The next important step when turning with a robot is to learn how to do an Arc turn.