US 4,466,054 AGranted

Improved proportional integral-derivative control apparatus

AssigneeTokyo Shibaura Denki Kabushiki Kaisha

InventorsTakashi Shigemasa, Yasuo Takagi

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Abstract

A process control apparatus is provided which has a PID controller to which is supplied a sampled signal of a control deviation signal of a process value signal and a reference signal and which generates a PID control signal according to sampled-value PID control constants. A non-linear controller is connected in parallel with the PID controller. A sum signal of the output signals from the PID controller and the non-linear controller is supplied to a process through a holding circuit. The process control apparatus further includes a circuit for identifying the dynamic characteristic of the process according to the sum signal and the sampled signal of the process value, and a circuit for calculating a transfer function of the process in the Laplace operator domain and for determining the sampled-value PID constants of the PID controller according to the dynamic characteristic.

Claims5

Dependent claims

A process control apparatus comprising:

first sampling means for sampling a control deviation signal of a process value signal and a reference signal;
PID controlling means for performing a sampled-value PID calculation with respect to an output signal from said first sampling means by using sampled-value PID control constants and for generating a PID control signal;
non-linear controller means for converting an output signal from said first sampling means to a non-linear signal;
holding means for holding a sum signal of the PID control signal and the non-linear signal and for supplying a hold signal controlling a process value to a process;
second sampling means for sampling the process value signal;
and
control constant generating means for calculating sampled-value PID control constants on the basis of an output signal from said second sampling means and the sum signal of the PID control signal and the non-linear signal and for supplying an operation result to said PID controlling means.

4 more elements

Dependencies are inferred from the claim text.