Jetbot from Waveshare is moving too fast

Hi. Recently I buyed Jetbot AI kit from Waveshare.

We need this bot for line following, however IA doesn’t work since the speed of the motors seems too high (if I decrease the speed below a soil, the robot stops immediately, so I need to keep speed high in order to not going under the soil).

My question is: my robot is somehow broken or is a common problem of the Waveshare kit? Road following and collision avoidance examples seems to be unusable.

Thanks in advance

Hi asantangelo90,

Please check below link if can gain some ideas:
https://www.waveshare.com/wiki/JetBot_AI_Kit

Sorry for my english, by ‘soil’ i meant ‘threshold’. So to recap: my problem is that the motors run too fast, and i cannot slow down the robot enough. If i decrease speed under a 25% threshold, the motors stop. Any ideas why?