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- echo on
- %
- % HIMAT_X3
- %
- % It is assumed that you have just run 'himat_x2'.
- %
- % This MATLAB script file is the third iteration of mu-synthesis
- % control design for the HIMAT pitch axis control problem.
- %
- % Third iteration of the mu-synthesis procedure. Design a
- % H-infinity control law for the new interconnection structure
- % which includes the frequency varying d-scales. HIMAT_IC3
- % has 20 states, 6 outputs and 6 inputs.
-
- [k3,g3,gf3]=hinfsyn(himat_ic3,2,2,0.95,1.10,.05,2);
-
- % Now a H-infinity control law has been designed which achieves an
- % infinity norm of .9875 for the new interconnection structure.
- % The new system includes the frequency varying d-scales fit in
- % the second iteration. To verify the gamma value, a frequency
- % response of the closed loop is done and the maximum
- % singular value of the closed-loop response across frequency
- % is plotted. We will also
- % check that the closed-loop poles are stable.
-
- pause % strike any key to continue
- format short e
- rifd(spoles(g3))
- pause % strike any key to continue
- g3g=frsp(g3,om2);
- g3pk=pkvnorm(g3g);
- echo off
- fprintf( '\n final gamma %g, \n max singular value %g \n \n',gf3,g3pk)
- echo on
- g3gs=vsvd(g3g);
- vplot('liv,m',g3gs)
- echo off
- title('Singular value plot of Third Iteration in mu-synthesis');
- xlabel('Frequency (rad/s)');
- ylabel('Magnitude');
- grid;
- echo on
- pause % strike any key to continue
-
- % The H-infinity control law can be analyzed using mu-analysis. The
- % closed-loop system, G3, has 4 inputs and 4 outputs. The block
- % structure again is a 2x2 full uncertainty block corresponding to
- % actuator multiplicative uncertainty and a 2x2 full performance
- % block weighting the output sensitivity.
-
- pause % strike any key to continue
- [bnds3,dv3,sens3,rp3]=mu(g3g,blk);
-
- % plot the maximum singular value and mu on the same plot
- % solid - maximum singular value
- % dashed - mu
-
- both=sbs(sel(g3gs,1,1),bnds3);
- vplot('liv,m',both)
- echo off
- title('Max. singular value and mu for the closed-loop system, g3');
- xlabel('Frequency (rad/s)');
- ylabel('Magnitude');
- grid;
- pause % strike any key to continue
- echo on
-
- % clear variables not used and pack the memory space due
- % to the limitations on the Mac and PC's.
-
- clear rp3 g3g g3gs both
- pack
-
- % The next step is the fit the d-scales which are output from
- % the MU program. The MUSYNFIT function is used to fit
- % the d-scales for each individual block. Next we fit a new
- % set of d-scales based on the new H-infinity control law.
-
- % MUSYNFIT requires the left d-scale from the previous
- % mu-synthesis iteration (DSYSL) to avoid increasing the states
- % with each iteration. The d-scales from the mu-analysis
- % problem, DV2, and the sensitivity of the d-scales, SENS2,
- % along with the block structure, number of controller
- % inputs and outputs. For the second
- % iteration, DSYSL is used for the left d-scale.
- % Output from MSYNFIT is the new left d-scale and right
- % d-scale to be multiplied into the interconnection structure.
-
- pause % strike any key to continue
-
- % We recommend a a 3rd order transfer function. This increases
- % the number of states in the interconnection structure to
- % 3*(size of full block)*2. If one selects a different order
- % for the d-scale weight, the gamma iteration will converge
- % to a different value.
-
- [dsysl,dsysr]=musynfit(dsysl,dv3,sens3,blk,2,2);
-
- % Now, wrap the new d-scales around the original
- % interconnection structure.
-
- % himat_ic4 = dsysl*himat_ic*(dsysr)^-1
-
- pause % strike any key to continue
- himat_ic4=mmult(dsysl,himat_ic,minv(dsysr));
- % clear dsysr g3 g3pk
- pack;
- minfo(himat_ic4)
-
- % Thus ends the third iteration of mu-synthesis. Notice that
- % the new interconnection structure has 20 states, only 12
- % more states than the original interconnection structure.
- % The 12 states that were in the system from the previous
- % iteration have already been scaled into the
- % d-scale fitting routine (Note, this is of course if you
- % fit the d-scales using a 3rd order system.)
-
- % Type in 'himat_x4' to continue with the fourth and final
- % iteration of mu-synthesis control design.
- %
- % Copyright MUSYN INC 1991, All Rights Reserved
-