Jitter is the most common problem in discrete control, and there are generally two reasons, 1. The long control period is generally caused by insufficient sampling frequency. 2. The controller has poor transient response ability and poor robustness, which is generally the reason.

If the balance car is a nonlinear system, it is normal for the patch to be dithered by linear PID control, because the system energy will not always converge when the parameters are small in linear control, so the PID control parameters are often local overshoot, resulting in poor transient response. Stickers can add an integral term to the system to balance the residual of the system or add a first-order filter to the output signal, so as to make the car balance smooth at the expense of robustness.