Human walking is dynamic, stable, and energy efficient. To achieve such remarkable legged locomotion in robots, engineers have explored bipedal robots developed based on two paradigms: trajectory-controlled and passive-based walking. Trajectory-controlled bipeds often deliver energy-inefficient gaits. The reason is that these bipeds are controlled via high-impedance geared electrical motors to accurately follow predesigned trajectories. Such trajectories are designed to keep a biped locally balanced continually while walking. On the other hand, passive-based bipeds provide energy-efficient gaits. The reason is that these bipeds adapt to their natural dynamics. Such gaits are stable limit-cycles through entire walking motion, and do not require being locally balanced at every instant during walking. However, passive-based bipeds are often of round/point foot bipeds that are not capable of achieving and experiencing standing, stopping, and some important bipedal gait phases and events, such as the double support phase. Therefore, the goals of this thesis are established such that the aforementioned limitations on trajectory-controlled and passive-based bipeds are resolved. Toward the above goal, comprehensive simulation and experimental explorations into bipedal walking have been carried out. Firstly, a novel systematic trajectory-controlled gait-planning framework has been developed to provide mechanical insights into bipedal walking in terms of gait characteristics and energy efficiency. For the same purpose, a novel mathematical model of passive-based bipedal walking with compliant hip-actuation and compliant-ankle flat-foot has been developed. Finally, based on mechanical insights that have been achieved by the aforementioned passive-based model, a physical prototype of a passive-based bipedal robot has been designed and fabricated. The prototype experimentally validates the importance of compliant hip-actuation in achieving a highly dynamic and energy efficient gait.

Constitutional change is relentless. Today, states jockey with regional associations, international organizations, transnational networks and sub-state authorities to define the scope of legitimate political conduct and establish rival bases for political affiliation. Constitutional theorists must be resolute but they should not be rigid. Especially in such uncertain conditions, theories are best understood not as plans to be implemented but as hypotheses to be tested. Charles Sabel and David Dyzenhaus write separately but share this pragmatic orientation, in which doubt is indispensable and truth is the end of public inquiry. They also share a distinctive belief that constitutionalism serves a moral end: it is the project of cultivating citizens who conceive their political community in terms of the commitments revealed by its practices. Their position, which is well suited for contemporary challenges, warrants elaboration and examination. British Columbia offers an ideal constitutional laboratory for that test. During the 1970s and 1980s, doubts mounted about the legitimacy of the constitutional settlement imposed by the Crown in the westernmost province of Canada. Legal, political and constitutional decisions raised the possibility that aboriginal rights and title survived colonization and Confederation. Since 1990, their existence has been confirmed in a cascade of constitutional experiments. Those initiatives can be distilled into four procedures: litigation, negotiation, consultation and collaboration. Although they have delivered practical benefits to some indigenous peoples, these procedures have not transformed provincial politics into a moral endeavour. The constraints on constitutionalism in British Columbia are both conceptual and institutional. Despite marginal improvements, those constraints endure and constitutionalism remains for now the sporadic pursuit of a small elite. To conceive constitutionalism as a project is to set a sound but exacting standard. Although British Columbia falls short, its failure is informative: the theory is useful.

Zugl.: Bonn, Univ., Diss., 2006

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.

Examensarbete.

Lic.-avh. (sammanfattning) Skara : Sveriges lantbruksuniversitet, 2006. / Härtill 2 uppsatser.