Model ElementPinput element defines the inputs to a mechanical system or plant.
Description
This is part of the information necessary to create a linearized model of the plant or for
co-simulation. You also need to specify the outputs to the plant using the
POUTPUT element. Given the inputs and outputs, you may use
the Simulate command of type Linear to compute the matrices in the following
linearized, state space form:
(1)
x(t) are the states, u(t) are the inputs, and y(t) are the outputs. A, B, C, and D denote the
state matrix, the input matrix, the output matrix, and the direct feed-through
matrix, respectively. These matrices are often useful as a starting point in control
systems design.
Attribute Summary
Name |
Property |
Modifiable by
command? |
Designable? |
id |
Int
() |
|
No |
label |
Str
() |
Yes |
variables |
Reference ("Variable", count=0) |
|
hold_order |
Int
(-1) |
Yes |
sampling_period |
Double () |
Yes |
offset_time |
Double () |
Yes |
Usage
Pinput (variables=objList, optional_attributes):
Attributes
- variables
- List of Variables
- Specifies a list of Variables that define the inputs to
the plant.
- This attribute is mandatory.
- id
- Integer
- Specifies the element identification number. This number must be unique
among all the Pinput objects in the model.
- This attribute is optional. MotionSolve will
automatically create an ID when one is not specified.
- Range of values: id > 0
- label
- String
- Specifies the name of the Dsurface object.
- This attribute is optional. When not specified, MotionSolve will create a label for you.
- hold_order
- Int
- Specifies the order of interpolation applied to the control signal(s)
propagating out from Control_PlantInput. The default
value is 1.0.
- sampling_period
- Double
- Specifies the sample time of an input port. A value of 0.0 specifies
continuous sampling while any other non-zero value specifies discrete
sampling. This value cannot be negative. The default value is 0.0. In most
cases, this value need not be changed from its default, except in models
where a discrete sampling is required. This parameter is to be used only in
the case of co-simulation with MATLAB/Simulink.
- offset_time
- Double
- Specifies the sample time offset for each input port. The sample time offset
must be strictly less than the sampling_period if the
latter is non-zero. If the sampling_period is 0.0
(continuous), then offset_time defaults to 0.0 as well.
In most cases, this value need not be changed from its default, except in
models where a discrete sampling is required. This parameter is to be used
only in case of co-simulation with MATLAB/Simulink.
Example:
Create a
Pinput with two variables: an angle and an angular
velocity.
var1 = Variable ( function="AZ(21,11)", label="Joint Angle")
var2 = Variable ( function="WZ(21,11,11)", label="Joint Angular Velocity")
pin1 = Pinput (label="Joint Angle & Velocity", variables=[var1, var2])