Adaptive control

Adaptive control

Adaptive control involves modifying the control law used by a controller to cope with the fact that the parameters of the system being controlled are slowly time-varying or uncertain. For example, as an aircraft flies, its mass will slowly decrease as a result of fuel consumption; we need a control law that adapts itself to such changing conditions. Adaptive control is different from robust control in the sense that it does not need a priori information about the bounds on these uncertain or time-varying parameters; robust control guarantees that if the changes are within given bounds the control law need not be changed, while adaptive control is precisely concerned with control law changes.

Classification of adaptive control techniques

In general one should distinguish between:

# Feedforward Adaptive Control
# Feedback Adaptive Control

There are several broad categories of feedback adaptive control (classification can vary):

* Dual Adaptive Controllers [based on Dual control theory]
** Optimal Controllers
** Suboptimal Dual Controllers
* Nondual Adaptive Controllers
** Gain scheduling
** Model Reference Adaptive Controllers (MRACs) [incorporate a "reference model" defining desired closed loop performance]
*** Gradient Optimization MRACs [use local rule for adjusting params when performance differs from reference]
*** Stability Optimized MRACs
** Model Identification Adaptive Controllers (MIACs) [perform System identification while the system is running]
*** Cautious Adaptive Controllers [use current SI to modify control law, allowing for SI uncertainty]
*** Certainty Equivalent Adaptive Controllers [take current SI to be the true system, assume no uncertainty]
**** Nonparametric Adaptive Controllers
**** Parametric Adaptive Controllers
***** Explicit Parameter Adaptive Controllers
***** Implicit Parameter Adaptive Controllers

Some special topics in adaptive control can be introduced as well:

# Adaptive Control Based on Discrete-Time Process Identification
# Adaptive Control Based on the Model Reference Technique
# Adaptive Control based on Continuous-Time Process Models
# Adaptive Control of Multivariable Processes
# Adaptive Control of Nonlinear Processes


When designing adaptive control systems, special consideration is necessary of convergence and robustness issues.

Typical applications of adaptive control are (in general):

* Self-tuning of subsequently fixed linear controllers during the implementation phase for one operating point;
* Self-tuning of subsequently fixed robust controllers during the implementation phase for whole range of operating points;
* Self-tuning of fixed controllers on request if the process behaviour changes due to ageing, drift, wear etc;
* Adaptive control of linear controllers for nonlinear or time-varying processes;
* Adaptive control or self-tuning control of nonlinear controllers for nonlinear processes;
* Adaptive control or self-tuning control of multivariable controllers for multivariable processes (MIMO systems);

Usually these methods adapt the controllers to both the process statics and dynamics. In special cases the adaptation can be limited to the static behavior alone, leading to adaptive control based on characteristic curves for the steady-states or to extremum value control, optimizing the steady state. Hence, there are several ways to apply adaptive control algorithms.

See also

*Nonlinear control
*Intelligent control


Further reading

* K. J. Astrom and B. Wittenmark, Adaptive Control, Addison-Wesley, 1989, 2d ed. 1994.
* [ Shankar Sastry and Marc Bodson, Adaptive Control: Stability, Convergence, and Robustness, Prentice-Hall, 1989-1994]

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • adaptive control — adaptyvusis valdymas statusas T sritis automatika atitikmenys: angl. adaptive control vok. adaptive Regelung, f; adaptive Steuerung, f; anpassungsfähige Steuerung, f rus. адаптивное управление, n pranc. commande adaptative, f …   Automatikos terminų žodynas

  • Adaptive Control of Thought — (ACT), ursprünglich Active Control of Thought, ist eine kognitionspsychologische Theorie zur Erklärung der kognitiven Leistungen (u.a. Denken, Sprache und Gedächtnis) des Menschen. Sie wurde 1983 von John R. Anderson erstmals vorgestellt und… …   Deutsch Wikipedia

  • adaptive control — the ability of a control unit to adapt its closed loop operation to changing operating conditions such as engine wear, fuel quality or altitude to maintain proper air fuel mixture control, ignition timing or idle rpm. Also referred to as self… …   Dictionary of automotive terms

  • adaptive control — noun A form of control system whose parameters may be changed dynamically in order to adapt to a changing environment …   Wiktionary

  • adaptive-control function — noun That part of a control system that dynamically updates the parameters of an optimizing control function or a direct control function …   Wiktionary

  • Adaptive Control — Anpassung dynamischer Systeme mithilfe von Instrumenten, die einen gewünschten Zustand des Systems dadurch herbeiführen wollen, dass bei Störungen des Systems zielkonforme Reaktionen ausgelöst werden (Baetge). Den höchsten Grad der… …   Lexikon der Economics

  • self-adaptive control — susiderinamasis valdymas statusas T sritis automatika atitikmenys: angl. self adaptive control vok. selbstadaptierende Regelung, f; selbsttätig abgleichende Regelung, f rus. самонастраивающееся управление, n pranc. commande auto adaptative, f …   Automatikos terminų žodynas

  • adaptive control model — /əˌdæptɪv kən trəυl ˌmɒd(ə)l/ noun US a model for planning advertising expenditure in line with changes in consumer responses to advertising …   Marketing dictionary in english

  • Adaptive Regelung — wird in der Regelungstechnik eine Regelung genannt, die ihre Parameter an den Prozess anpassen kann. Die adaptive Regelung wird eingesetzt, da eine normale Regelung nur relativ kleine Änderungen in der Prozess Dynamik ausgleichen kann. Deshalb… …   Deutsch Wikipedia

  • Control engineering — Control systems play a critical role in space flight Control engineering or Control systems engineering is the engineering discipline that applies control theory to design systems with predictable behaviors. The practice uses sensors to measure… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”