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...
How to create text files (.txt) from Dymola
Text files, with the file extension .txt, are a popular choice for storing data. Lightweight and small in size, they are easy to read, update and distribute. By virtue of storing only the data regarding the ASCII characters within, often only a simple programme such as notepad is required...
ADAS testing in a virtual environment
The virtual testing and development of Advanced Driver Assistance Systems (ADAS) places very similar requirements on our simulation tools to those needed to support Autonomous Vehicle development. These requirements are: The ability to create scenarios with multiple actors (traffic and pedestrians) A wide range of sensor models including camera,...
How not to size an Array
There are certain requirements for setting the size of an array to a parameter in Modelica. This post has a closer look into what these requirements are. A simple example Figure 1 is a simple example of sizing vector b with parameter n. In the example in Figure 1...
Restricted domestic water flow impact on energy consumption
I thought we’d have a look at some interesting non-automotive applications for my next few blog posts. I’ve been meaning to write some for a while. Speaking to one of my colleagues in South Africa I learnt about his area’s reduced domestic water flow in a bid to save...