Motors and motor power influence on the robot movement. Experiment with Gyro Pro Preview

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.

  • #652
  • 09 Jan 2018
  • 7:21

Different deviation for different motor power

The speed of the robot has great influence on the traction between the tires and the surface. This is the first thing that you have to be careful about. It also seems that with larger motor power there are greater deviations from the straight line, probably because the motors get out of sync for longer periods. 

Influence of the battery

Value of "100" in the block for moving forward generally means that the robot is moving forward as fast as it can. As fast as the weight of the robot allows it and as fast as the battery allows it. So the LEGO Mindstorms robot is doing it's best, but this means that the robot depends on the battery. When the battery is drained the robot will have different behaviour. That is not good. You should always try to develop robots that do not depend on the battery for their precision. 


The experiment shows a plot of the current power and the value of the gyro sensor. Try to analyse the plot. What conclusions can you make from the it. 

EV3-G experiment plotting the Gyro Sensor and the Current Power

The experiment contains a plot of the Curren Power of Motors B and C and the values of the Gyro Sensor when the robot is moving with a power of 100%. What you could see is that it is not actually moving with a power of 100% because the current power is about 75-80%.