Towards a neural hierarchy of time scales for motor control

Animals show remarkable rich motion skills which are still far from realizable with robots. Inspired by the neural circuits which generate rhythmic motion patterns in the spinal cord of all vertebrates, one main research direction points towards the use of central pattern generators in robots. On of the key advantages of this, is that the dimensionality of the control problem is reduced. In this work we investigate this further by introducing a multi-timescale control hierarchy with at its core a hierarchy of recurrent neural networks. By means of some robot experiments, we demonstrate that this hierarchy can embed any rhythmic motor signal by imitation learning. Furthermore, the proposed hierarchy allows the tracking of several high level motion properties (e.g.: amplitude and offset), which are usually observed at a slower rate than the generated motion. Although these experiments are preliminary, the results are promising and have the potential to open the door for rich motor skills and advanced control

An investigation of air and water dual adjustment decoupling control of surface heat exchanger

The terminal equipment of central cooling system accounts for a significant proportion of the total system's energy consumption. Therefore, it is important to reduce the terminal equipment energy consumption in central air conditioning system. In this study, the difference of the effect of the chilled water flow rate and air supply rate on the surface cooler during the heat transfer process is taken into full account. Matlab/Simulink simulation software is used to model and simulate the heat transfer of surface cooler of the main terminal equipment of air conditioning system. Simulation tests and experimental validations are conducted by using variable chilled water flow rate and variable air supply rate control mode separately. The experiment results show that the simulation model can effectively predict the heat transfer performance of heat exchanger. Further, the study introduced a dual feedback control mode, which synchronously regulates the chilled water flow rate and air supply rate. Also, under certain conditions, the complex heat transfer process of the surface cooler can be decoupled, and single variable control pattern is used to separately regulate the chilled water flow rate and air supply rate. This can effectively shorten the system regulation time, reduce overshoot and improve control performance

V-like formations in flocks of artificial birds

We consider flocks of artificial birds and study the emergence of V-like formations during flight. We introduce a small set of fully distributed positioning rules to guide the birds' movements and demonstrate, by means of simulations, that they tend to lead to stabilization into several of the well-known V-like formations that have been observed in nature. We also provide quantitative indicators that we believe are closely related to achieving V-like formations, and study their behavior over a large set of independent simulations

EPSRC IMPACT Exhibition

This exhibition was conceived by Dunne (PI) and comprised 16 mixed-media speculative design research projects. It marked the culmination of an EPSRC-funded initiative also partly supported by NESTA. Dunne supervised and then curated the projects by staff, graduates and students of the RCA Design Interactions programme. Each was conducted in collaboration with an external research partner organisation already supported by the EPSRC. The topics covered ranged from renewable energy devices and security technologies to the emerging fields of synthetic biology and quantum computing. Dunne and an advisory panel from EPSRC and NESTA selected themes on the basis of diversity of topic, design opportunities, intellectual and creative challenges, and public relevance. Dunne invited the designers to take a radical, interrogative approach, exploring the social, ethical and political implications of the research. Each designer visited the relevant science lab, consulted with the scientists throughout the project, and participated in a one-day workshop hosted by NESTA between scientists and designers on such forms of collaboration. Designers carried out literature, journal, and project surveys before developing their projects through iterative prototypes. The exhibition, held at the RCA in 2010, was considered by EPSRC to offer a powerful insight into how today’s research might transform our experience of the world. It was reviewed in the Guardian (2010), Wired (2010) and Design Week (2010). Dunne presented ‘IMPACT!’ in conferences including the IDA Congress, ‘Design at the Edges’, Taipei (2011) and at the Wellcome Trust, London (2011). He gave a related lecture to researchers at Microsoft Research Asia, Beijing (2011). Individual exhibits from the project featured in exhibitions: Museum of Modern Art (2011), National Museum of China (2011); Z33 (2010–11); Wellcome Trust (2010–11); Saint-Étienne International Design Biennial (2010); Ars Electronica (2010); The Times Cheltenham Science Festival (2010); and V2_, Institute for the Unstable Media (2010)

Transition to subcritical turbulence in a tokamak plasma

Tokamak turbulence, driven by the ion-temperature gradient and occurring in the presence of flow shear, is investigated by means of local, ion-scale, electrostatic gyrokinetic simulations (with both kinetic ions and electrons) of the conditions in the outer core of the Mega-Ampere Spherical Tokamak (MAST). A parameter scan in the local values of the ion-temperature gradient and flow shear is performed. It is demonstrated that the experimentally observed state is near the stability threshold and that this stability threshold is nonlinear: sheared turbulence is subcritical, i.e. the system is formally stable to small perturbations, but, given a large enough initial perturbation, it transitions to a turbulent state. A scenario for such a transition is proposed and supported by numerical results: close to threshold, the nonlinear saturated state and the associated anomalous heat transport are dominated by long-lived coherent structures, which drift across the domain, have finite amplitudes, but are not volume filling; as the system is taken away from the threshold into the more unstable regime, the number of these structures increases until they overlap and a more conventional chaotic state emerges. Whereas this appears to represent a new scenario for transition to turbulence in tokamak plasmas, it is reminiscent of the behaviour of other subcritically turbulent systems, e.g. pipe flows and Keplerian magnetorotational accretion flows.Comment: 16 pages, 5 figures, accepted to Journal of Plasma Physic