Pid Algorithms and Their Computer Implementation

摘要

Positional, incremental, and cascade PID algorithms and their closed-loop properties are discussed. Avoidance of integral windup and derivative kick is described. Ways in which the PID algorithm can be discretized for use in a digital computer are outlined, together with appropriate FORTRAN coding. The effect of choice of sample interval on the discretized performance is analyzed. Often the interval is chosen to be as short as possible given the computational power available; the influence of this on quantization noise and offset is discussed. The properties of the anti-aliasing filter and a filter on derivative action are investigated. Nonlinear filters, including spike filters, are presented.