Creating and Modifying Linear State Equations |
The following procedure explains how to a linear state equation.
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To create or modify a linear state equation:
From the Build menu, point to System Elements, point to Linear State Equation, and then select either New or Modify.
The Part Modify or Create Equation Linear State Equation dialog box appears. Both dialog boxes contain the same options.
If you selected New, change the name of the linear state equation element, if desired, and assign a unique ID number to it. Learn about ADAMS/Solver IDs.
Add or change any comments about the equation element that you want to enter to help you manage and identify the element. Learn about comments.
Enter the arrays and matrices in the next text boxes as explained below.
X State Array Name - Enter the array element that defines the state array for the linear system. The array must be a states (X) array. It cannot be used in any other linear state equation, general state equation, or transfer function.
U Input Array Name - Enter the array element that defines the input (or control) array for the linear system. Entering an inputs (U) array is optional. The array must be an inputs (U) array. If you enter an inputs (U) array, you must also specify either a B input matrix, a D feedforward matrix, or both.
The B and D matrices must have the same number of columns as there are elements in the inputs (U) array.
Y Output Array Name - Enter the array element that defines the column matrix of output variables for the linear system. Entering an outputs (Y) array is optional. If you enter an outputs (Y) array, you must also specify a C output matrix or a D feedforward matrix. The corresponding matrix elements must have the same number of rows as there are elements in the outputs (Y) array. It also must be an outputs (Y) array, and it cannot be used in any other linear state equation, general state equation, or transfer function.
IC Array Name - Enter the array element that defines the column matrix of initial conditions for the linear system. Entering the IC array is optional. The IC array must have the same number of elements as the states (X) array (equal to the number of rows in the A state matrix). When you do not specify an IC array, ADAMS/Solver initializes all states to zero.
A State Matrix Name - Enter the matrix data element that defines the state transition matrix for the linear system. The matrix must be a square matrix (same number of rows and columns), and it must have the same number of columns as the number of rows in the states (X) array.
B Input Matrix Name - Enter the matrix data element that defines the control matrix for the linear system. The B input matrix must have the same number of rows as the A state matrix and the same number of columns as the number of elements in the inputs (U) array.
Entering a B input matrix is optional. If you enter a B input matrix, you must also include an inputs (U) array.
C Output Matrix Name - Enter the matrix data element that defines the output matrix for the linear system. The C output matrix must have the same number of columns as the A state matrix and the same number of rows as the number of elements in the outputs (Y) array. Entering a C output matrix is optional. If you enter a C output matrix, you must also include an outputs (Y) array name.
D Feedforward Matrix Name - Enter the matrix data element that defines the feedforward matrix for the linear system. The D feedforward matrix must have the same number of rows as the number of elements in the Y output array and the same number of columns as the number of elements in the inputs (U) array.
When you enter a D feedforward matrix, you must also include both a Y output matrix and an inputs (U) array.
Set Static hold to yes to hold states at the constant value determined during static and quasi-static simulations; no if they can change. Learn about controlling equilibrium values when using system elements.
Select OK.