Development of wireless network system on a power wheelchair
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
The development of wireless communication technology offers new opportunities to enhance the functionalities of mobility systems (e.g. powers wheelchairs and robots). This thesis presents new hardware and software architecture to offer ease of user control and power efficiency to an autonomous mobility system by using Wireless Networked Control (WSC). A wireless network is applied to perform both environment sensing and user control. The development will be demonstrated through a case study on a power wheelchair. The challenge in the development of such a wireless solution is to accomplish a set of system activities (e.g. system initialization, system monitoring, power management) under different circumstances within a dynamic wireless network without sacrificing flexibility, energy-efficiency, or reliability. The optimal way to achieve this is to design a protocol stack orientated to the demand of a specific system with cross-layer optimization. However, it requires significant design effort. In this thesis, a wireless network is constructed by utilizing a commercial-of-the-shelf (COTS) protocol. The development focuses on system integration and Application Layer. This accelerates the development progress with the benefits of cost effectiveness and less burden on protocol design. However, the COTS protocol is not able to provide a solution with maximum efficiency, because that the development of a COTS protocol is constrained by many factors. For example, the low layers of a COTS protocol are usually not available for customization due to the license issue. The aim of this project is to develop a wireless platform to enable wireless functional devices to be added into a mobile system. The main benefit of such a wireless network system (WNS) is to allow new modules to be readily incorporated into the mobility system, which otherwise are difficult, because either, the physical wiring is prohibitive or the current system does not allow the signals to be processed. The strategy for developing such a wireless network with desired functionalities is to build both identity management module and power management module based upon system design and Application Layer development. The identity management module allows the system to perform self-construction and self-maintenance and the power management offers high power efficiency. These two modules are developed independently and integrated into an autonomous control loop. Transitions between different modules are achieved by handshaking protocols. The advantage of such a strategy is the ease for customization and extension. The infrastructure includes gateway, Log-in system and radio frequency (RF) platform.