Showing papers on "PID controller published in 1971"

Simplified procedure for tuning pid controllers

Abstract: Simplified procedures for tuning a PID controller are disclosed wherein variable circuit elements in the reset and rate networks are mechanically ganged together to permit simultaneous and proportionate control of the circuit parameters in those two networks.

Predictive position feedback controller for web guide control system

Abstract: An electronic controller for a process control system for use with a bi-directional single speed actuating device wherein the controller includes a proportional plus integral mode with predictive position feedback.

Circuit for pneumatic controllers

Abstract: A circuit for pneumatic PID controllers including a differential pressure amplifier having positive and negative feedback paths each including a timing element and a pressure divider wherein a buffer amplifier is connected between the timing element and the control point pressure divider and/or between the timing element and the setpoint pressure divider for energy decoupling.

Adaptive control of a chemical process system

Abstract: Modification of parameters in the conventional controller equation usually is necessitated by uncontrollable process parameter drifts which occur during the operation of the large scale continuous processes typically found in the chemical industry. To this end, a normalized version of the model reference adaptive control system, including suitable procedures for adjusting the adaptive loop gains, was developed and demonstrated to provide excellent adaptive performance for a single concentration control loop for a simulated stirred-tank chemical reactor. The three constants in a conventional PID controller were simultaneously adjusted to accomplish this adaptation. Equally excellent adaptive performance was achieved in an interacting control loop scheme simulated by control of both the concentration and the temperature in the same stirred-tank reactor. In both cases adaptation was achieved in a time interval which was sufficiently short to make this method of adaptive control feasible for use in a real processing situation. Models needed for implementation of the model reference adaptive control scheme were easily developed. In a real application these models could be easily developed from studies which could take place during prestartup or early operations of the process; hence no a priori knowledge would be required. A wide range of adaptive loop gains was demonstrated to provide a stable overall control system. A high degree of stability was demonstrated for the overall system despite the initiation of large extraneous load upsets occurring during the operation of the adaptive control system. The method presented has not been rigorously proven to be applicable to every real control problem requiring adaptive control. However, the method was demonstrated to be highly effective over a wide range of required controller adjustments in cases similar to those encountered in large continuous processes. Thus the method merits serious consideration for possible implementation whenever adaptive control is required.

Application of three-mode controllers for nonlinear system synthesis

Abstract: A compensator design scheme illustrating the application of a proportional plus integral plus derivative (PID) control action for absolute stability of nonlinear systems is presented. The proportional plus integral (PI) and PID control actions are compared using the circle criterion. The design approach presented is digital computer oriented. Analog simulations substantiate the results.