Discrete state-space system

Library

Linear

Description

This block realizes a discrete-time linear state-space system. The system is defined by the $(A,B,C,D)$ matrices and the initial state $x_0$. The dimensions must be compatible. At the arrival of an input event on the unique input event port, the state is updated.

Dialog Box

Set discrete linear system parameters
A matrix	-1
B matrix	1
C matrix	1
D matrix	0
Initial state	0

• A matrix: square matrix. TheA matrix
• B matrix: theB matrix
• C matrix: the C matrix
• D matrix: theD matrix
• Initial state $x_0$: vector. The initial state of the system.

Default properties

• always active: no
• direct-feedthrough: no
• zero-crossing: no
• mode: no
• number/sizes of inputs: 1 / 1
• number/sizes of outputs: 1 / 1
• number/sizes of activation inputs: 1 / 1
• number/sizes of activation outputs: 0 /
• continuous-time state: no
• discrete-time state: yes
• name of computational function: dsslti

Interfacing function

scilab/macros/scicos_blocks/linear/DLSS_f.sci

Computational function (type 1)

      subroutine dsslti(flag,nevprt,t,xd,x,nx,z,nz,tvec,ntvec,
     &     rpar,nrpar,ipar,nipar,u,nu,y,ny)
c     Copyright INRIA

c     Scicos block simulator
c     discrete state space linear system simulator
c     rpar(1:nx*nx)=A
c     rpar(nx*nx+1:nx*nx+nx*nu)=B
c     rpar(nx*nx+nx*nu+1:nx*nx+nx*nu+nx*ny)=C
c
      double precision t,xd(*),x(*),z(*),tvec(*),rpar(*),u(*),y(*)
      integer flag,nevprt,nx,nz,ntvec,nrpar,ipar(*)
      integer nipar,nu,ny
      double precision w(100)
c
c
      la=1
      lb=nz*nz+la
      lc=lb+nz*nu
      if(flag.eq.4) then
         if(nz.gt.100) then
            flag=-1
            return
         endif
      elseif(flag.eq.2) then
c     x+=a*x+b*u
         call dcopy(nz,z,1,w,1)
         call dmmul(rpar(la),nz,w,nz,z,nz,nz,nz,1)
         call dmmul1(rpar(lb),nz,u,nu,z,nz,nz,nu,1)
      elseif(flag.eq.1.or.flag.eq.6) then
c     y=c*x+d*u
         ld=lc+nz*ny
         call dmmul(rpar(lc),ny,z,nz,y,ny,ny,nz,1)
         call dmmul1(rpar(ld),ny,u,nu,y,ny,ny,nu,1)
      endif
      end