A discrete-time approach to process modeling and direct digital control.

The purpose of this study was to investigate the advantages offered by a z-transform approach to direct digital control applications. A discrete-time modeling package was developed for modeling process input/output data using a general second-order pulse transfer function. Also, a z-transform controller presented in the literature was modified to yield a control algorithm which gives significant improvement over conventional DOC algorithms

Advances in PID, Smith and Deadbeat control

Ph.DDOCTOR OF PHILOSOPH

Application of deadbeat controllers and pole placement methodologies for friction compensation in mechanical systems

Cataloged from PDF version of article.Friction is an almost unavoidable component of many mechanical systems. When not taken into account in designing control systems, the effect of friction may result in the degradation of controlled system performance. This thesis deals with the problem of designing a control system, for friction compensation in mechanical systems, via pole placement and deadbeat methodologies. Pole placement design is based on different performance measures and indices such as settling time, overshoot and ITAE. Deadbeat controller design is based on parameterization of Diophantine equations which depend on the reference signal to be tracked. System performance is analyzed on simulation level by the application of the two methodologies in a hierarchical feedback system structure, which provides both position and velocity control separately. Simulation results show that both methodologies provide acceptable performance as compared to the existing compensation schemes in literature and control performances are improved with respect to their accuracy of tracking. In addition, deadbeat controller is observed to be more promising in terms of minimum settling time.Karahasanoğlu, Çınar YeşilM.S

Modified active disturbance rejection control for time-delay systems

Industrial processes are typically nonlinear, time-varying and uncertain, to which active disturbance rejection control (ADRC) has been shown to be an effective solution. The control design becomes even more challenging in the presence of time delay. In this paper, a novel modification of ADRC is proposed so that good disturbance rejection is achieved while maintaining system stability. The proposed design is shown to be more effective than the standard ADRC design for time-delay systems and is also a unified solution for stable, critical stable and unstable systems with time delay. Simulation and test results show the effectiveness and practicality of the proposed design. Linear matrix inequality (LMI) based stability analysis is provided as well