Openloop Unstable Processes

In the last chapter we used Laplace-domain techniques to study the dynamics and stability of simple closedloop control systems. In this chapter we want to apply these same methods to more complex systems cascade control, feedforward control, openloop unstable processes, and processes with inverse response. Finally we will discuss an alternative way to look at controller design that is called model-based control. [Pg.376]

Can we make the system stable by using feedback control That is, can an openloop unstable process be made closedloop stable by appropriate design of the feedback controller Let us try a proportional controller = The... [Pg.393]

B. SECOND-ORDER OPENLOOP UNSTABLE PROCESS. Consider the process given in Eq. (11.44) with a first-order lag added. [Pg.393]

Root locus curves for openloop unstable processes (positive poles). [Pg.394]

C. THIRD-ORDER OPENLOOP UNSTABLE PROCESS. If an additional lag is added to the system and a proportional controller is used, the closedloop characteristic equation becomes... [Pg.395]

Make root locus plots of first- and second-order openloop unstable processes with PI feedback controllers. [Pg.408]

Find the closedloop stability requirements for a third-order openloop unstable process with a proportional controller ... [Pg.408]

Find the value of feedback controller gain K, that gives a closedloop system with a damping coeflicient of 0.707 for a second-order openloop unstable process with... [Pg.408]

An openloop unstable process has a transTer function containing a positive pole at... [Pg.411]

Keep in mind that we are talking about closedloop stability and that we are studying it by making frequency-response plots of the total openlaop system transfer function. We are also considering openlocp stable systems most of the time. We will show how to deal with openloop unstable processes in Sec. 13.4. [Pg.470]

The Nyquist stabihty criterion can be used for openloop unstable processes, but we have to use the complete, rigorous version with P (the number of poles of the closedloop characteristic equation in the RHP) no longer equal to zero. [Pg.490]

SAMPLED-DATA CONTROL OF OPENLOOP UNSTABLE PROCESSES... [Pg.705]

Example 20.9. The simplest openloop unstable process has the openloop transfer function... [Pg.706]

An openloop-unstable process has a transfer function containing a positive pole at -I- 1/t and a negative pole at — 1/ot. Its steady-state gain is unity. If a proportional-only controller is used, what is the value of a that gives a closedloop damping coefficient of 0.5 when the controller gain is 10 times the minimum gain ... [Pg.334]

We consider openloop-stable systems most of the time. We show how to deal with openloop-unstable processes in Section 11.4. [Pg.386]

Linear Feedforward Control / 9.2.2 Nonlinear Feedforward Control Openloop-Unstable Processes... [Pg.598]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...