dynamics_controls Module

Uses

- dynamics_error_handling
- iso_fortran_env
- nonlin_polynomials
- ieee_arithmetic
- ferror
- diffeq

Contents

Interfaces

operator(*) ss_excitation

Derived Types

state_space transfer_function

Functions

lti_solve

Interfaces

public interface operator(*)

private function tf_tf_mult(x, y) result(rst)

Multiplies two transfer functions.

Arguments

Type	Intent	Optional	Attributes		Name
class(transfer_function),	intent(in)			::	x	The left-hand-side argument.
class(transfer_function),	intent(in)			::	y	The right-hand-side argument.

Return Value type(transfer_function)

The resulting transfer function.

private function poly_tf_mult(x, y) result(rst)

Multiplies a polynomial and a transfer function to result in a new transfer function.

Arguments

Type	Intent	Optional	Attributes		Name
class(polynomial),	intent(in)			::	x	The left-hand-side argument.
class(transfer_function),	intent(in)			::	y	The right-hand-side argument.

Return Value type(transfer_function)

The resulting transfer function.

private function tf_poly_mult(x, y) result(rst)

Multiplies a transfer function and a polynomial to result in a new transfer function.

Arguments

Type	Intent	Optional	Attributes		Name
class(transfer_function),	intent(in)			::	x	The left-hand-side argument.
class(polynomial),	intent(in)			::	y	The right-hand-side argument.

Return Value type(transfer_function)

The resulting transfer function.

private function tf_scalar_mult(x, y) result(rst)

Multiplies a transfer function by a scalar value.

Arguments

Type	Intent	Optional	Attributes		Name
class(transfer_function),	intent(in)			::	x	The left-hand-side argument.
real(kind=real64),	intent(in)			::	y	The right-hand-side argument.

Return Value type(transfer_function)

The resulting transfer function.

private function scalar_tf_mult(x, y) result(rst)

Multiplies a transfer function by a scalar value.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=real64),	intent(in)			::	x	The left-hand-side argument.
class(transfer_function),	intent(in)			::	y	The right-hand-side argument.

Return Value type(transfer_function)

The resulting transfer function.

interface

public subroutine ss_excitation(t, u, args)

A routine for computing the excitation vector for a state-space model.

Arguments

Type	Intent	Optional	Attributes		Name
real(kind=real64),	intent(in)			::	t	The time value at which to compute the excitation.
real(kind=real64),	intent(out),		dimension(:)	::	u	The excitation vector.
class(*),	intent(inout),	optional		::	args	An optional argument used to pass objects in and out of the routine.

Derived Types

type, public :: state_space

Defines a state-space representation of a dynamic system. This implementation takes the form:

Components

Type	Visibility	Attributes		Name		Initial
real(kind=real64),	public,	allocatable, dimension(:,:)	::	A			The N-by-N dynamics matrix, where N is the number of state variables.
real(kind=real64),	public,	allocatable, dimension(:,:)	::	B			The N-by-M input matrix, where M is the number of inputs.
real(kind=real64),	public,	allocatable, dimension(:,:)	::	C			The P-by-N output matrix, where P is the number of outputs.
real(kind=real64),	public,	allocatable, dimension(:,:)	::	D			The P-by-M feedthrough matrix.

type, public :: transfer_function

Defines a transfer function for a continuous system of the form $H(s) = \frac{Y(s)}{X(s)}$ .

Components

Type	Visibility	Attributes		Name		Initial
type(polynomial),	public		::	X			The denominator polynomial $X(s)$ in $H(s) = \frac{Y(s)}{X(s)}$ . The polynomial coefficients are stored in acending order such that $x_1 + x_2 s + x_3 s^2 ...$ .
type(polynomial),	public		::	Y			The numerator polynomial $Y(s)$ in $H(s) = \frac{Y(s)}{X(s)}$ . The polynomial coefficients are stored in acending order such that $y_1 + y_2 s + y_3 s^2 ...$ .

Type-Bound Procedures

generic, public :: evaluate => tf_eval_omega, tf_eval_s
generic, public :: initialize => tf_init_poly, tf_init_array
procedure , public :: poles => tf_poles Function
procedure , public :: to_ccf_state_space => tf_to_ccf_statespace Function
procedure , public :: to_ocf_state_space => tf_to_ocf_statespace Function
procedure , public :: zeros => tf_zeros Function

Functions

public function lti_solve(mdl, u, t, ic, solver, args, err) result(rst)

Solves the LTI system given by the specified state space model.

Arguments

Type	Intent	Optional	Attributes		Name
class(state_space),	intent(in)			::	mdl	The state_space model to solve.
procedure(ss_excitation),	intent(in),		pointer	::	u	The routine used to compute the excitation vector.
real(kind=real64),	intent(in),		dimension(:)	::	t	The time points at which to compute the solution. The array must have at least 2 values; however, more may be specified. If only 2 values are specified, the integrator will compute the solution at those points, but it will also return any intermediate integration steps that may be required. However, if more than 2 points are given, the integrator will return the solution values only at the specified time points.
real(kind=real64),	intent(in),		dimension(:)	::	ic	The initial condition vector. This array must be the same size as the number of state variables.
class(ode_integrator),	intent(in),	optional,	target	::	solver	The ODE solver to utilize. If not specified, the default solver is a 4th/5th order Runge-Kutta integrator.
class(*),	intent(inout),	optional		::	args	An optional container for arguments to pass to the excitation routine.
class(errors),	intent(inout),	optional,	target	::	err	An error handling object.

Return Value real(kind=real64), allocatable, dimension(:,:)

The solution. The time points at which the solution was evaluated are stored in the first column and the output(s) are stored in the remaining column(s).