Concurrent design and analysis of the Navigator wearable computer system: the thermal perspective

Abstract

This paper describes the concurrent design of a wearable computer, called the Navigator, developed and built at Carnegie Mellon University in a multidesigner, multidomain environment. The design effort for the Navigator involved nineteen designers, representing the electronics, mechanical, industrial, software and human-computer interaction disciplines. The evolution of the multidisciplinary design is described, with particular emphasis placed upon the role of the thermal design group in the overall design process. Furthermore, the particular challenges associated with the concurrent thermal management of wearable computer systems are outlined. I. IntroductionConsumer desire for increased computational functionality has resulted in the development of portable computers. Portable computers, as exemplified by today's notebook machines, required technical innovations in both hardware and software to overcome the challenges presented by the associated size, weight, and power consumption constraints. Additional constraints, which are market imposed, result from the highly competitive nature of the computer industry, necessitating shorter time-tomarket, higher levels of quality, and lower cost. The satisfaction of these competition-driven constraints requires the achievement of domain specific objectives, such as clock speed, without the violation of any seemingly unrelated global constraints, such as reliability. Additional design iterations, required to correct any unresolved constraints or unanticipated flaws, lengthens the development cycle. Competition has reduced the acceptable development cycle to less then twelve months which, eliminates the time needed for additional design iterations. Therefore, the participation of the entire design team is required to insure that a discipline-specific modification does not adversely affect other performance objectives.The recognition of the multidiscipline nature of design has fostered interest in concurrent design, through which the concerns of a design team are accounted for in a collaborative effort. This cooperative approach improves communication between designers, with the intent that resultant products are error

Thermal management and concurrent system design of a wearable multicomputer

“…For wearable computers, the outer casing of the housing must incorporate the heat sink to facilitate natural convection heat removal. The heat sink must not only satisfy thermal design but also aesthetic and ergonomic criteria and serve the dual purpose of dissipating heat and providing robustness and rigidity to the housing structure [1]. Because thermal design is highly dependent on and constrained by other disciplines, personal interaction with designers from other disciplines is necessary, thus demanding a cohesive design framework in which progress at all levels is performed concurrently.…”

“…Our research focuses on the thermal and system design of computers that are portable, lightweight, and rugged. These computers are meant to be worn and used on the body and are known as wearable computers [1], [14]. The main subject of discussion for this paper is the concurrent thermal design of the Navigator2 wearable computer.…”

Rapid design and manufacture of wearable computers

“…For example, a thermal design methodology for wearable computers, developed in response to the needs of the designers, is described in [2]. In the wearable computers, the thermal properties depend on the electronics (and hence, indirectly, the software), the housing shape, and the manufacturing process.…”

System design approach to power aware mobile computers

“…For most generations of CMU wearable computers, we have performed extensive power management and optimization research, and Figure 1 shows just several of these examples [1,6,7,8].…”