mirror of
https://github.com/nasa/trick.git
synced 2024-12-25 15:51:05 +00:00
85 lines
2.2 KiB
Markdown
85 lines
2.2 KiB
Markdown
|
# SIM_MSD
|
||
|
|
|
||
|
|
SIM\_MSD is a simulator for a mass-spring-damper system.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
The system is described by the equation _mẍ_ + _bẋ_ + _kx_ = _F_, where:
|
||
|
|
|
||
|
|
_m_ is the mass of an object.
|
||
|
|
|
||
|
|
_x_ is the position of the mass.
|
||
|
|
|
||
|
|
_b_ is the damping coefficient.
|
||
|
|
|
||
|
|
_k_ is the spring coefficient.
|
||
|
|
|
||
|
|
_F_ is an external force applied to the mass.
|
||
|
|
|
||
|
|
---
|
||
|
|
### Building the Simulation
|
||
|
|
|
||
|
|
In the SIM_MSD directory, execute **trick-CP** to build the simulation executable. When it's complete, you should see:
|
||
|
|
|
||
|
|
```
|
||
|
|
=== Simulation make complete ===
|
||
|
|
```
|
||
|
|
|
||
|
|
Now **cd** into models/Graphics/ and type **make**. This builds the display client for the simulation.
|
||
|
|
|
||
|
|
### Running the Simulation
|
||
|
|
In the SIM_MSD directory:
|
||
|
|
|
||
|
|
```
|
||
|
|
% ./S_main_*.exe RUN_test/input.py
|
||
|
|
```
|
||
|
|
|
||
|
|
The following windows should appear:
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
### Controlling the Simulation
|
||
|
|
Click **Start** to begin the simulation.
|
||
|
|
|
||
|
|
Click **Reset** to freeze the simulation and reset the position and velocity to
|
||
|
|
their initial conditions.
|
||
|
|
|
||
|
|
Change **Position** and **Velocity** to adjust the initial conditions for those
|
||
|
|
attributes.
|
||
|
|
|
||
|
|
Change **Mass**, **Spring Coefficient**, **Damping Coefficient**, and **Applied
|
||
|
|
Force** to adjust initial conditions _**and**_ also update the sim in real-time.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
---
|
||
|
|
The following inputs can be set in any of the RUN_*/input.py files to change
|
||
|
|
the inputs on startup
|
||
|
|
### Inputs
|
||
|
|
|
||
|
|
Variable | Type | Units | Default Value
|
||
|
|
---------- |-----------|-------|--------------
|
||
|
|
dyn.msd.x_0 | double | m | 5.0
|
||
|
|
dyn.msd.v_0 | double | m/s | 0.0
|
||
|
|
dyn.msd.b | double | N.s/m | 0.5
|
||
|
|
dyn.msd.k | double | N/m | 2.0
|
||
|
|
dyn.msd.F | double | N | 5.0
|
||
|
|
dyn.msd.m | double | kg | 1.0
|
||
|
|
|
||
|
|
---
|
||
|
|
Some sample input.py files have been created to demonstrate different
|
||
|
|
mass-spring-damper conditions
|
||
|
|
### Samples
|
||
|
|
|
||
|
|
Path |Type
|
||
|
|
------------------------|----------------------------------------------
|
||
|
|
RUN_underdamp/input.py |Underdamped Harmonic Oscillator
|
||
|
|
RUN_critdamp/input.py |Critically Damped Harmonic Oscillator
|
||
|
|
RUN_overdamp/input.py |Overdamped Harmonic Oscillator
|
||
|
|
RUN_nodamp/input.py | Simple Harmonic Oscillator (No Damping Force)
|