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h2hinfsyn

MixedH2/Hsynthesis with regional pole placement constraints

Syntax

[K,CL,normz,info] = h2hinfsyn(P,Nmeas,Ncon,Nz2,Wz,Name,Value)

Description

[K,CL,normz,info] = h2hinfsyn(P,Nmeas,Ncon,Nz2,Wz,Name,Value)employs LMI techniques to compute an output-feedback control lawu=K(s)yfor the control problem of the following illustration.

The LTI plantPhas partitioned state-space form given by

x ˙ = A x + B 1 w + B 2 u , z = C 1 x + D 11 w + D 12 u , z 2 = C 2 x + D 21 w + D 22 u , y = C y x + D y 1 w + D y 2 u .

The resulting controllerK:

  • Keeps theHnormGof the transfer function fromwtozbelow the value you specify using theName,Valueargument“HINFMAX”.

  • Keeps theH2normHof the transfer function fromwtoz2below the value you specify using theName,Valueargument'H2MAX'.

  • Minimizes a trade-off criterion of the form

    W 1 G 2 + W 2 H 2 ,

    whereW1andW2are the first and second entries in the vectorWz.

  • Places the closed-loop poles in the LMI region that you specify using theName,Valueargument'REGION'.

Use the input argumentsNmeas,Ncon, andNz2to specify the number of signals iny,u, andz2, respectively. You can use additionalName,Valuepairs to specify additional options for the computation.

Input Arguments

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Plant, specified as an LTI model such as atforssmodel.Pmust be a continuous-time model.

Number of measurement signals, specified as a positive integer. This value is the number of signals iny.

Number of control signals, specified as a positive integer. This value is the number of signals inu.

Number of signals subject to the constraint on theH2norm, specified as a positive integer. This value is the number of signals inz2. If the total number of outputs ofPisNout, then the firstNout - Nz2 - Nmeasoutputs ofPare subject to the constraint on theHnorm.

Weights forHandH2performance, specified as a 1-by-2 vector of the form[Winf,W2].

Name-Value Pair Arguments

Specify optional comma-separated pairs ofName,Valuearguments.Nameis the argument name andValueis the corresponding value.Namemust appear inside single quotes (' '). You can specify several name and value pair arguments in any order asName1,Value1,...,NameN,ValueN.

例子:'REGION',reg,'H2MAX',1,'HINFMAX',1,'DISPLAY','on'

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Pole placement region, specified as a comma-separated pair consisting of'REGION'and a matrix of the form[L,M]. This matrix specifies the pole placement region as:

{ z : L + z M + z ¯ M T < 0 } .

Generate the matrix usinglmireg. The default LMI region for pole placement, specified by the empty matrix[], is the open left-half plane, enforcing closed-loop stability only.

Upper bound on theH2norm of the transfer function fromwtoz2, specified as a comma-separated pair consisting of'H2MAX'and a positive scalar value orInf. The default valueInfis equivalent to setting the limit to zero, and causesh2hinfsynto minimize theH2norm subject to the trade-off criterion.

例子:'H2MAX',1

Upper bound on theHnorm of the transfer function fromwtoz, specified as a comma-separated pair consisting of“HINFMAX”and a positive scalar value orInf. The default valueInfis equivalent to setting the limit to zero, and causesh2hinfsynto minimize theHnorm subject to the trade-off criterion.

例子:“HINFMAX”,1

Bound on the norm on the feedthrough matrixDKof the controller, specified as a comma-separated pair consisting of'DKMAX'and a nonnegative scalar value. To make the controllerKstrictly proper, set'DKMAX'to 0.

例子:'DKMAX',0

Desired relative accuracy on the optimal value of the trade-off criterion, specified as a comma-separated pair consisting of'TOL'and a positive scalar value.

Toggle for screen display of synthesis information, specified as a comma-separated pair consisting of'DISPLAY'and either'on'or“关闭”.

Output Arguments

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Optimal output-feedback controller, returned as a state-space (ss) model withNmeasinputs andNconoutputs.

Closed-loop system with synthesized controller, returned as a state-space (ss) model. The closed-loop system isCL = lft(P,K).

Closed-loop norms, returned as a 1-by-2 vector. The entries in this vector, respectively, are:

  • TheHnorm of the closed-loop transfer function fromwtoz.

  • TheH2norm of the closed-loop transfer function fromwtoz2.

Solutions of LMI solvability conditions, returned as a structure containing the following fields:

  • R— SolutionRof LMI solvability condition

  • S— SolutionSof LMI solvability condition

References

[1] Chilali, M., and P. Gahinet, "HDesign with Pole Placement Constraints: An LMI Approach,"IEEE Trans. Aut. Contr., 41 (1995), pp. 358–367.

[2] Scherer, C., "Mixed H2/H-infinity Control,"Trends in Control: A European Perspective斯普林格出版社(1995), pp.173–216.

See Also

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Introduced before R2006a

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