An Introduction to System Modelling – 1. Before Building the Models
This is the first in a series introducing the best approach, preparation and practice when system modelling. This post specifically investigates what you should consider before you start modelling. Modelling a system can be a difficult task to get right. There are many things to consider before approaching a...
Dymola 2020x keyboard shortcuts for the ribbon
Dymola 2020x has an improved user interface and in the process has modified keyboard shortcuts for accessing functionality that previously was on the toolbar and is now on the ribbon. This blog post looks at the new keyboard shortcuts used to navigate the Dymola ribbon and select the tools....
What’s New in Dymola 2020x
Eagle eyed users will immediately notice that this year’s second release of Dymola breaks with the usual naming tradition; gone is the FD01 designation, in is the “x” nomenclature, but that’s not the only thing to change. The user GUI has undergone a complete overhaul, modernised to render a...
Requirements for effective systems modelling
Over the past …. erm, many years I have come across different types of systems that have been modelled in a range of software tools, mainly with the aim of performing reduced cost and much faster “what-if” analysis by removing the need for building as many physical prototypes. Despite...
Simulation Settings Stored In The Class Annotation
In the Modelica language, the annotation keyword is used to define graphics, documentation, menus and many other attributes that do not affect the behaviour of the system modelled. In this post I’m going to focus on the class annotations that let you store the simulation settings used to control...
Why PID control gains need to be positive in feedback control
This blog post explains why PID control gains need to be positive. It is important to understand how PID controller works first. The post will consider stability analysis of each control action, i.e. proportional, integral and derivative control individually. Examples and figures are used to demonstrate the result. Tuning...
Automatically Getting Derivatives of a Function in Dymola
In a prior post, I wrote about manually specifying derivatives of a function in Dymola. This is necessary in certain cases, especially when external code is used. For the simple function I used in that post and many functions like it, however, there is actually a much easier answer....
Durability Tests with OpenCRG Roads
The VeSyMA libraries have been used for many different applications, including durability studies. Such studies usually involve recreating a range of different experiments, situations and sometimes very extreme tests designed to push components to their limits. The purpose of these tests is two-fold; firstly, evaluating vehicle response to normal...
The Atkinson cycle and improving the ICE’s efficiency
INTRODUCTION The Internal Combustion Engine (ICE) is one of the most innovative creations the human being has made, in my opinion. The objective of its creation was to be the main source of power to propel vehicles all the way to the modern car as we all know it...
Applying Derivatives to Functions in Dymola
So here is one of the toughest errors to debug in Dymola: When a model fails to translate with “Failed to reduce the DAE index” it is usually the start of a very frustrating day. The problem, in this case, is that Dymola needs to differentiate a specific equation...