Part create equation general_state_equation

Allows you to create an existing general_state_equation.

The equation command allows you to create and manage equation elements in your model. These elements include differential_equations, transfer_functions, linear_state_equations, and general_state_equations. EQUATIONS help you model controls system elements or any other phenomena that can be represented by differential equations. Adams View makes it easier for you to identify these equations by allowing you to assign them names and drawing them as icons on the screen. During preprocessing, the icons for the EQUATIONs you create are displayed at or near the origin of your model by Adams View. All EQUATIONs are "owned" by a particular model and then you reference these EQUATIONs in the definition of other model objects.

A GENERAL_STATE_EQUATION is used along with associated ARRAYs and user-subroutines to define a system of explicit differential and (optionally) algebraic equations in state-space form. The state derivatives and outputs for a GENERAL_STATE_EQUATION may be user defined functions of the states, inputs, and time. The GENERAL_STATE_EQUATION is designed to model a nonlinear, time-varying system. It is especially useful in importing nonlinear system models developed elsewhere, into Adams. The set of coupled differential and algebraic equations which can be expressed in matrix notation as:

The GENERAL_STATE_EQUATION definition is restricted to explicit functions of the states and inputs. However, because the VARIABLEs included in the u_input_array can be completely general, the user can write GENERAL_STATE_EQUATION equations that implicitly depend on any available Adams variable. The GENERAL_STATE_EQUATION follows standard control systems terminology, where X is the state array, Y is the output array, U is the input array, and IC is the initial condition array, X(t=0). In Adams View, each of these vectors is defined using an particular ARRAY. All ARRAY sizes must be consistent with the GENERAL_STATE_EQUATION definition. ARRAYs with zero-size and zero-valued partial derivative matrices should not be defined; Adams will correctly formulate the system equations based on those ARRAY statements and derivatives which do exist. The current values for the state derivative and output vectors of this GENERAL_STATE_EQUATION are computed in the user-supplied GSESUB subroutine (see the Adams Users Manual section on the "GSESUB"), much as the user would do for any other user-written subroutine. Additionally, the user must provide GSEXX, GSEXU, GSEYX and GSEYU subroutines (see the proper sections in the Adams Users Manual for a description of these routines) to compute the necessary internal partial derivatives in accordance with the values of df_dx_method, df_du_method, dg_dx_method, and the dg_du_method flags.