The stability of the control object refers to the oscillation tendency of the dynamic process of the system and its ability to return to the relative equilibrium state. For a stable system, when the output deviates from the equilibrium, the output value should be able to converge gradually and finally return to the relative equilibrium state. Stability is a prerequisite to ensure the normal operation of the system. The control accuracy of the control system is measured by the steady-state error, which reflects the later performance of the dynamic process. Speed refers to the degree to which the deviation between the input and output of the system is eliminated.