Analysis of linear L1 adaptive control architectures for aerospace applications

Pettersson, Anders; Åström, Karl Johan; Robertsson, Anders; Johansson, Rolf

doi:10.1109/cdc.2012.6426682

Cited by 6 publications

(9 citation statements)

References 9 publications

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“…For comparison, the output of the optimal control law uðsÞ ¼ CðsÞðk g rðsÞÀθxðsÞÞ is given. As expected, the L 1 controllers approximate the bahaviour of the equivalent LTI controller (10), and not the behaviour of the optimal controller (7) that leads to an offset in the case of output disturbances.…”

Section: Example Without Unmodeled Dynamicssupporting

confidence: 52%

“…Analysis of more complex L 1 algorithms would be beneficial to clarify their characteristics. Pettersson et al [10] noted that despite the LTI behaviour, the L 1 controllers seem suitable for flight control applications. Analysis of the LTI equivalent system and comparison with other LTI techniques may lead to the development of LTI control structures that are beneficial for specific applications.…”

Section: Discussionmentioning

confidence: 99%

“…Some specific L 1 adaptive control formulations have been shown to be LTI for all adaptation gains [10,11,6]. Recent results on robustness of L 1 adaptive control are also based on LTI formulations [7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of L1 adaptive state feedback control. Why does it approximate an implementable LTI controller?

Heusden

Talebian

Dumont

2015

European Journal of Control

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Section: Example Without Unmodeled Dynamicssupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of L1 adaptive state feedback control. Why does it approximate an implementable LTI controller?

Heusden

Talebian

Dumont

2015

European Journal of Control

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“…In the L1-controller an estimation of the input-load disturbance ˆ is performed 11 . These matched and unmatched parameter estimates 1 and 2 are shown in Fig.…”

Section: E Comments On Simulation Resultsmentioning

confidence: 99%

“…his work is part of a feasibility study of adaptive control for winged aircraft and missiles 10, 11 . Reference models are required when using adaptive control methods such as MRAC 1,2 or L1 adaptive control 3 .…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Feedforward and Reference Systems for Adaptive Flight Control

Pettersson

Åström

Robertsson

et al. 2013

AIAA Guidance, Navigation, and Control (GNC) Conference

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Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and the same models can also be used as reference models in adaptive control. A method for designing the reference models is presented in the paper. By exploiting the structure of the equations describing air vehicles it is possible to find reference models that scale to the present flight condition and vehicle configuration. Such reference systems are derived for flying vehicles in a generic manner, suitable for both winged aircraft and missiles. The same type of reference systems are also used to create trajectories for feedforward signals that compensate known plant non-linearities.Nomenclature v = vehicle velocity vector, with vector elements u, v and w = vehicle angular velocity vector, with vector elements p, q and r V = airspeed, the norm of the velocity vector = angle of attack = angle of sideslip m, I i = mass and mass inertia tensor F , M = force and moment acting on vehicle = density of air at the vehicle altitude S, b, c = reference area and reference lengths, related to aerodynamic properties of the vehicle a , e , r = control surface deflections, aileron, elevator, rudder L = state-feedback gain H m (s) = desired transfer function from plant input to output K g = steady state inverse gain of desired transfer function from plant input to output

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