voltage output from both motor drivers is significantly different.

Dear DFROBOT

This is Hangu Elementary School. Around last year, 17 robots were purchased from a Korean agency, and when I used them for the first time this year, I found a problem with severe motor deviation.
 

At first, I thought one robot was wrong, but after testing a few robots, I found out that most of them had problems.
 

The problem is that the speed difference between the left and right motors is severe. 

This means that the straightness of the robot is poor and it is difficult to predict the speed deviation.
 

​Of course, I understand that there is some deviation in the DC motor. This seems to be a circuit problem, not a motor problem.
 

When I measured the voltage in the motor driver part with a circuit tester, I was surprised. The voltage output from both motor drivers is significantly different.
 

Mainly, the output value of the left motor driver was low, which showed similar symptoms no matter what battery and power source were used. The students were sensitive during their activities and were full of complaints.
 

I've used Maqueen since it first came out, and I've used most Maqueen robots, but this is the first time I've had such a big deviation.
 

Also, at my recommendation, another school also purchased this robot this year, and the robot package contained ribbons and rings that are commonly used in batteries. I didn't see them in my robot. It felt like I was the first user to become an exclusive tester. TT
 

Several extremely severe and abnormal robots are requested to be replaced, and for robots to be manufactured later, it is hoped that the motor driver part will be supplemented. Please listen to my opinion.