Robustness analysis of evolutionary controller tuning using real systems

A genetic algorithm (GA) presents an excellent method for controller parameter tuning. In our work, we evolved the heading as well as the altitude controller for a small lightweight helicopter. We use the real flying robot to evaluate the GA's individuals rather than an artificially consistent simulator. By doing so we avoid the ldquoreality gaprdquo, taking the controller from the simulator to the real world. In this paper we analyze the evolutionary aspects of this technique and discuss the issues that need to be considered for it to perform well and result in robust controllers

Real-time evolution of an embedded controller for an autonomous helicopter

In this paper we evolve the parameters of a proportional, integral, and derivative (PID) controller for an unstable, complex and nonlinear system. The individuals of the applied genetic algorithm (GA) are evaluated on the actual system rather than on a simulation of it, thus avoiding the ldquoreality gaprdquo. This makes implicit a formal model identification for the implementation of a simulator. This also calls for the GA to be approached in an unusual way, where we need to consider new aspects not normally present in the usual situations using an unnaturally consistent simulator for fitness evaluation. Although elitism is used in the GAs, no monotonic increase in fitness is exhibited by the algorithm. Instead, we show that the GApsilas individuals converge towards more robust solutions

Supervised Control of a Flying Performing Robot using its Intrinsic Sound

We present the current results of our ongoing research in achieving efficient control of a flying robot for a wide variety of possible applications. A lightweight small indoor helicopter has been equipped with an embedded system and relatively simple sensors to achieve autonomous stable flight. The controllers have been tuned using genetic algorithms to further enhance flight stability. A number of additional sensors would need to be attached to the helicopter to enable it to sense more of its environment such as its current location or the location of obstacles like the walls of the room it is flying in. The lightweight nature of the helicopter very much restricts the amount of sensors that can be attached to it. We propose utilising the intrinsic sound signatures of the helicopter to locate it and to extract features about its current state, using another supervising robot. The analysis of this information is then sent back to the helicopter using an uplink to enable the helicopter to further stabilise its flight and correct its position and flight path without the need for additional sensors

Managing uncertainty in sound based control for an autonomous helicopter

In this paper we present our ongoing research using a multi-purpose, small and low cost autonomous helicopter platform (Flyper ). We are building on previously achieved stable control using evolutionary tuning. We propose a sound based supervised method to localise the indoor helicopter and extract meaningful information to enable the helicopter to further stabilise its flight and correct its flightpath. Due to the high amount of uncertainty in the data, we propose the use of fuzzy logic in the signal processing of the sound signature. We discuss the benefits and difficulties using type-1 and type-2 fuzzy logic in this real-time systems and give an overview of our proposed system

Lattice baryon spectroscopy with multi-particle interpolators

In 2 + 1 flavour lattice QCD the spectrum of the nucleon is presented for both parities using local meson-baryon type interpolating fields in addition to the standard three-quark nucleon interpolators. The role of local five-quark operators in extracting the nucleon excited state spectrum via correlation matrix techniques is explored on dynamical gauge fields with $m_\pi$ = 293 MeV, leading to the observation of a state consistent with the S-wave $N\pi$ scattering threshold in the negative-parity sector. Furthermore, the robustness of the variational technique is examined by studying the spectrum on a variety of operator bases. Fitting a single-state ansatz to the eigenstate-projected correlators provides robust energies for the low-lying spectrum that are essentially invariant despite being extracted from qualitatively different bases.Comment: 13 Pages, 12 Figures, Updated version as appears in PR

The end of consensus? Folk theory and the politics of foreign policy in the Brexit referendum

While it is well-known that Brexit will have consequences for the UK’s role in the world, foreign affairs is not thought to have featured prominently in the referendum campaign itself. This apparent lack of foreign policy salience is surprising given the broader challenge to liberal international order provided by other anti-elite campaigns across Europe. In this article we analyse mentions of foreign affairs made by the Remain and Leave camps in the Brexit referendum campaign. We find that both campaigns articulated distinct views of Britain’s role in the world with regards to security, international organization, trade, morality, and regime-type. We argue these distinct perspectives represent “folk theories” of liberal internationalism and realism, respectively, given their correspondence with the core claims of these theoretical traditions. Our findings suggest that the goals of British foreign policy itself are likely to be increasingly subject of political division in the years after Brexit

A debate of the highest order:The Brexit referendum as second-order role contestation

The 2016 Brexit referendum re-ignited debate on the United Kingdom’s international role. Yet the stakes were complex, since neither side challenged Britain’s global leadership role nor strong ties with non-European partners. Research on role contestation has thus struggled to account for the politics of Brexit, focusing instead on non-role-based conflict. We argue that Brexit debates can be understood by reference to second-order role contestation, where role compatibility itself is the subject of political disagreements, a phenomenon role theory scholarship has missed by studying role conflict and role contestation in isolation. We distinguish between inclusive and exclusive second-order conceptions, which capture the respective positions of the Leave and Remain campaigns regarding Britain’s European role and its relation to other (shared) roles. Our argument shows that role conflict is often contested politically and that role contestation can operate at higher levels of abstraction than conventionally acknowledged