Abstract
Some problems of control over the Internet are presented. The mean problem for such control is unpredictable delays. Some statistics of delays for local net, wireless net and Internet is presented. It is obtained from experiments executed with developed software “Cloud mechatronic laboratory” (http://cmlaboratory.com). Several experiments of pendulums synchronization are considered. Hardware for experiments was constructed of Lego Mindstorms NXT. The advantages of “cloud mechatronic laboratory” for e-learning are discussed; also an overview of remote laboratories is presented.
TopIntroduction
With the development of the Internet the problem of remote education was introduced. One of the main problems of remote education is practical learning. For electrical engineering, physics, mechanics, etc., students need a laboratory for experiments. The modern Internet with optical or a wideband channel provides opportunities for creating remote real-time laboratories. According to Web of Science, the number of publications about “remote laboratory” rapidly increased:
Spreading Internet all over the world, greatly increased channel capacity, decreased delays and latency opens new horizons for creating remote laboratories. Control over network has difficulties – the existence of non-stationary delays in channel, mass-production and reduction of price usually leads to decreasing accuracy of sensors and regulators, lowering the quality of control plants. If someone wants to create an educational laboratory as a mechatronic plant plus remote controller, he should find a way to make regulator robust to non-stationary delays, non-zero latency, and finite capacity of digital network channel and robust to some specific characteristics of the Internet (see Figure 1).
Figure 1. The diagram about Web of Science the number of publications of “remote laboratory
Control of mechanical systems over networks is a new and rapidly expanding area of science. There are some papers (Andrievsky, 2013), about control of mechatronic systems over a special kind of network – Internet. In the paper Lum et al. (2009) several experiments for control of operators over different types of communication channels are presented: commercial internet, wirelesses LAN, Ethernet LAN, the feedback was based on a video-signal from different applications (iChat/Skype, HaiVision, Hai1000, Hai200 etc.). The problem of stabilizing an inverted pendulum over local net was studied in work Natale et al. (2004).
One of the first papers about remote (over Internet) laboratory was published in 1991 and it was about remote data analysis for physical experiments (Aburdene et al, 1991). The first introduction of concept of remote laboratory to educational process is the project “Second Best to Being There (SBBT)” started in University of Oregon in 1994. There are several researches about efficiency of remote laboratories in education. The following remote laboratories were developed and introduced to universities:
- 1.
The Virtual Lab of Carnegie Mellon University (http://www.ece.cmu.edu/˜stancil/virtuallab/virtual-lab.html);
- 2.
Controls and Process Dynamics Lab, the University of Tennessee at Chattanooga (http://chem.engr.utc.edu/);
- 3.
Bugscope, University of Illinois at Urbana-Champaign (http://bugscope.beckman.uiuc.edu/);
- 4.
I-Lab, Massachusetts Institute of Technology (https://wikis.mit.edu/confluence/display/ILAB2/);
- 5.
Microelectronics WebLab, Massachusetts Institute of Technology;
- 6.
Measurement Request Broker (MaRBLe), University of Illinois at Chicago;
- 7.
ITL on Line Lab, University of Colorado at Boulder;
- 8.
Automated Internet Measurement Laboratory, Rensselaer Polytechnic Institute .
Key Terms in this Chapter
Cloud Mechatronic Laboratory (CML): Is a distributed real-time software system consists of following elements: servers, clients, regulators.
Control with Delays: Is problems to use control over Internet.
Pendulum Control: Is demonstrate possibilities of cloud mechatronic laboratory we executed several experiments.
Control Over Network: Is client mean function is to be a uniform interface between cloud mechatronic laboratory and hardware plant.
Control Over Internet: Also is client mean function is to be a uniform interface between cloud mechatronic laboratory and hardware plant.
CML for E-Learning Systems: Is a good opportunity for E-Learning Systems; it can give cheap and powerful remote access for educational equipment with possibility of making experiments.
Lego Control: Is decided to use Lego constructor for creating control plant.