Application of variable zero-moment point in walking control of the biped robot

Using the predictive control based on zero-moment point (ZMP), the biped robot can walk comparatively stably. However, the problems such as lack of self-adaptivity are also highlighted mainly on account of modeling errors and environmental perturbations; specifically, the tracking errors of ZMP are generated, leading to a reduced walking stability. To address this problem, in the present work, the expected ZMP was decomposed into the reference ZMP which is pre-planned offline, and the variable ZMP which can be varied in real time. With the addition of the variable ZMP, the outside interferences can be eliminated. By combining the predictive control system and the inverse system of variable ZMP, the walking pattern of the robot with favorable self-adaptivity can be achieved. Finally, the simulation results indicate that the self-adaptivity of the robot can be effectively improved using the proposed control system

Adaptive Natural Oscillator to Exploit Natural Dynamics for Energy Efficiency

We present a novel adaptive oscillator, called Adaptive Natural Oscillator (ANO), to exploit the natural dynamics of a given robotic system. This tool is built upon the Adaptive Frequency Oscillator (AFO), and it can be used as a pattern generator in robotic applications such as locomotion systems. In contrast to AFO, that adapts to the frequency of an external signal, ANO adapts the frequency of reference trajectory to the natural dynamics of the given system. In this work, we prove that, in linear systems, ANO converges to the system's natural frequency. Furthermore, we show that this tool exploits the natural dynamics for energy efficiency through minimization of actuator effort. This property makes ANO an appealing tool for energy consumption reduction in cyclic tasks; especially in legged systems. We also extend the proposed adaptation mechanism to high dimensional and general cases; such as n-DOF manipulators. In addition, by investigating a hopper leg in simulation, we show the efficacy of ANO in face of dynamical discontinuities; such as those inherent in legged locomotion. Furthermore, we apply ANO to a simulated compliant robotic manipulator performing a periodic task where the energy consumption is drastically reduced. Finally, the experimental results on a 1-DOF compliant joint show that our adaptive oscillator, despite all practical uncertainties and deviations from theoretical models, exploits the natural dynamics and reduces the energy consumption

Towards a new hospital architecture: an exploration of the relationship between hospital space and technology

Present urban acute NHS hospitals are rigid architectural structures composed of spatial and medical planning requirements that are underpinned by complex inter-related relationships. One assumed relationship is medical technology’s affect upon hospital space. There’s limited research exploring the relationship between NHS hospital space and medical technologies. Furthermore, little is known about the implications of emerging technologies (ETs) on future urban acute NHS hospital space. This study investigates the link between hospital space and medical technology to visualise the spatial consequences of incorporating anticipated medical ETs into future urban acute NHS hospitals. A unique single futures prospective methodology is adopted with a mixed methods approach. This includes historical research, a quantitative investigation of four London case studies and a literature exploration of three medical ETs (biotechnology, robotics and cyborgization). Primary data generated from this study forms the basis for creating scenarios of future urban acute hospital environments. Findings reveal that medical technologies impact directly on hospital space, thus, confirming the existence of a link between hospital space and medical technologies. Results also reveal that even without nanotechnology progression, medical technologies decrease in equipment size during the course of their development. This trend contradicts recent medical planning practice which ‘super-sizes’ high-spec hospital rooms (see Chapter 3). Additionally, a campus-styled hospital typology is determined as the preferred flexible design solution for creating sustainable 21st century urban acute NHS hospitals. Findings lead to recommendations that guide medical planners with the future-proofing of acute hospital space by providing insight and alternative medical planning solutions that incorporate medical ETs into future urban acute NHS hospitals