I have the Lego Mindstorms EV3 Pack and built a simple car with 3 wheels. The back wheels are motorized.

When I run the following code:


both motors are rotating in different directions. I could understand if backward needs to be interpreted as forward. But how come that the motors are behaving differently?

It is basically not a big drama, I could build a wrapper to handle this. But still: When I want to use a chassis implementation, I would maybe run into that problem?


The "forward" and "backward" expressions are only interpreted in the reference frames of the motors themselves and translate to clockwise and counter-clockwise. In your case you must have mounted the motors in a way which requires them to rotate in different directions in order to propel the vehicle.

Consider a car with four wheels: in order to go forward, the wheels on the left hand side need to rotate counter-clockwise but those on the right side must turn clockwise.

While most chassis types share this property, it is indeed possible to build a chassis that requires both motors to be driven in the same direction for the vehicle to advance. In that case the program must be adjusted to accommodate for that.

  • thank you for the reply. I solved that Issue by simply turning and reassembling one motor. So now its fine:-) – weiterleiter Mar 7 '19 at 21:24
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