A computationally efficient method for calculating near-optimal solutions
to the three-objective, linear control allocation problem is disclosed.
The control allocation problem is that of distributing the effort of
redundant control effectors to achieve some desired set of objectives. The
problem is deemed linear if control effectiveness is affine with respect
to the individual control effectors. The optimal solution is that which
exploits the collective maximum capability of the effectors within their
individual physical limits. Computational efficiency is measured by the
number of floating-point operations required for solution. The method
presented returned optimal solutions in more than 90% of the cases
examined; non-optimal solutions returned by the method were typically much
less than 1% different from optimal and the errors tended to become
smaller than 0.01% as the number of controls was increased. The magnitude
of the errors returned by the present method was much smaller than those
that resulted from either pseudo inverse or cascaded generalized inverse
solutions. The computational complexity of the method presented varied
linearly with increasing numbers of controls; the number of required
floating point operations increased from 5.5 i, to seven times faster than
did the minimum-norm solution (the pseudoinverse), and at about the same
rate as did the cascaded generalized inverse solution. The computational
requirements of the method presented were much better than that of
previously described facet-searching methods which increase in proportion
to the square of the number of controls.