National Instruments ni matrixx xmath 用户手册

下载
页码 127
Chapter 1
Introduction
© National Instruments Corporation
1-5
Certain restrictions regarding minimality and stability are required of the 
input data, and are summarized in Table 1-1.
Documentation of the individual functions sometimes indicates how the 
restrictions can be circumvented. There are a number of model reduction 
methods not covered here. These include:
Padé Approximation
Methods based on interpolating, or matching at discrete frequencies
Table 1-1.  MRM Restrictions
balance( )
A stable, minimal system
balmoore ( )
A state-space system must be stable and minimal, 
having at least one input, output, and state
bst( )
A state-space system must be linear, 
continuous-time, and stable, with full rank along 
the j
ω-axis, including infinity
compare( )
Must be a state-space system
fracred( )
A state-space system must be linear and continuous
hankelsv( )
A system must be linear and stable
mreduce( )
A submatrix of a matrix must be nonsingular 
for continuous systems, and variant for discrete 
systems
mulhank( )
A state-space system must be linear, 
continuous-time, stable and square, with full 
rank along the j
ω-axis, including infinity
ophank( ) 
A state-space system must be linear, 
continuous-time and stable, but can be nonminimal
redschur( )
A state-space system must be stable and linear, 
but can be nonminimal
stable ( )
No restriction
truncate( )
Any full-order state-space system
wtbalance( )
A state-space system must be linear and 
continuous. Interconnection of controller and plant 
must be stable, and/or weight must be stable.