June 20, 2010
June 20, 2010
June 23, 2010
Electrical and Computer
15.868.1 - 15.868.15
Mesh-Networked Mobile Robots: A Framework of Laboratory Experiments for Courses in Wireless Communications
In this paper, we present an exemplary framework suitable for laboratory experiments for undergraduate courses in communications. Initially designed to be a test-bed for a small wireless mesh-networked system, the framework consists of a graphical user interface (GUI) for a control center, a software-based interface referred to as the Synapse Portal, a mesh-networking node referred to as the Bridge, and multiple mesh-networking End Nodes each of which is integrated into a three-wheel mobile robot. The development of the test-bed requires an integration of two microcontrollers of different code-execution speeds in cascade. In this paper, along with design details and relevant specifics of all components of the test-bed, we discuss issues encountered during the development and how we addressed them to successfully realize a functioning mesh network of mobile robots. Based on our observations during the development, we believe that the test-bed can be useful for addressing ABET engineering criteria, and also developing a set of small-scale laboratory experiments for undergraduate courses in the areas of communications.
The work presented in this paper initially began as a small research project involving master- level graduate students on indoor positioning. Research on indoor positioning has been intense over the past few years to facilitate a broader spectrum of location-based services and applications. It is well known that due to the inherent limitations of the satellite signals, the global positioning system (GPS)-based technologies do not work well in indoor environment. Several alternative approaches have been reported in the literature, and they can be classified largely into four categories: i) infrared signal-based, ii) ultrasound signal-based, iii) microwave (satellite) signal-based, and iv) radio-frequency (RF) signal-based. Partly due to the advantages in signal propagation under diverse indoor scenarios, the RF signal-based approach has become most popular for indoor positioning systems1-4. In these approaches, location estimation techniques are typically based on one or more of statistical parameters such as received signal strength (RSS), time of arrival (TOA), and angle of arrival (AOA). More recently, a new approach was proposed based on a new statistical parameter called the angle of transmission (AOT)5. The AOT is a spatial direction of the main lobe of a beam pattern generated by transmit- beamforming. The approach exploits the spatial information embedded in the signal transmitted from an antenna array. In this scheme, each mobile node with an omni-directional, single- element antenna estimates the AOT based on one (or more than one) signature signal(s) transmitted from the fixed node equipped with an antenna array. The mobile node then further estimates its distance from the fixed node based on the RSS of the signature signal to ultimately be able to pin-point its location in the polar coordinates where the fixed node is assumed to be at the origin.
Although our work on a prototype of an indoor positioning system exploiting AOT will need to be continued to the next stage, up to the current state as described below with more details, the
Lee, W., & Mutya, S. K., & Palthi, K. (2010, June), Mesh Networked Mobile Robots: A Framework Of Laboratory Experiments For Courses In Wireless Communications Paper presented at 2010 Annual Conference & Exposition, Louisville, Kentucky. 10.18260/1-2--15743
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