104 research outputs found
An integrated diagnostic architecture for autonomous robots
Abstract unavailable please refer to PD
Formalizing the Execution Context of Behavior Trees for Runtime Verification of Deliberative Policies
In this paper, we enable automated property verification of deliberative components in robot control architectures. We focus on formalizing the execution context of Behavior Trees (BTs) to provide a scalable, yet formally grounded, methodology to enable runtime verification and prevent unexpected robot behaviors. To this end, we consider a message-passing model that accommodates both synchronous and asynchronous composition of parallel components, in which BTs and other components execute and interact according to the communication patterns commonly adopted in robotic software architectures. We introduce a formal property specification language to encode requirements and build runtime monitors. We performed a set of experiments, both on simulations and on the real robot, demonstrating the feasibility of our approach in a realistic application and its integration in a typical robot software architecture. We also provide an OS-level virtualization environment to reproduce the experiments in the simulated scenario
Autosub Long Range 1500: A continuous 2000 km field trial
Long Range Autonomous Underwater Vehicles (LRAUVs) offer the potential to monitor the ocean at higher spatial and temporal resolutions compared to conventional ship-based techniques. The multi-week to multi-month endurance of LRAUVs enables them to operate independently of a support vessel, creating novel opportunities for ocean observation. The National Oceanography Centre’s Autosub Long Range is one of a small number of vehicles designed for a multi-month endurance. The latest iteration, Autosub Long Range 1500 (ALR1500), is a 1500 m depth-rated LRAUV developed for ocean science in coastal and shelf seas or in the epipelagic and meteorologic regions of the ocean. This paper presents the design of the ALR1500 and results from a five week continuous deployment from Plymouth, UK, to the continental shelf break and back again, a distance of approximately 2000km which consumed half of the installed energy. The LRAUV was unaccompanied throughout the mission and operated continuously beyond visual line of sight
Behaviour-driven motion synthesis
Heightened demand for alternatives to human exposure to strenuous and repetitive labour, as
well as to hazardous environments, has led to an increased interest in real-world deployment of
robotic agents. Targeted applications require robots to be adept at synthesising complex
motions rapidly across a wide range of tasks and environments. To this end, this thesis
proposes leveraging abstractions of the problem at hand to ease and speed up the solving. We
formalise abstractions to hint relevant robotic behaviour to a family of planning problems, and
integrate them tightly into the motion synthesis process to make real-world deployment in
complex environments practical. We investigate three principal challenges of this proposition.
Firstly, we argue that behavioural samples in form of trajectories are of particular interest to
guide robotic motion synthesis. We formalise a framework with behavioural semantic annotation
that enables the storage and bootstrap of sets of problem-relevant trajectories.
Secondly, in the core of this thesis, we study strategies to exploit behavioural samples in task
instantiations that differ significantly from those stored in the framework. We present two
novel strategies to efficiently leverage offline-computed problem behavioural samples: (i) online
modulation based on geometry-tuned potential fields, and (ii) experience-guided exploration
based on trajectory segmentation and malleability.
Thirdly, we demonstrate that behavioural hints can be extracted on-the-fly to tackle highlyconstrained, ever-changing complex problems, from which there is no prior knowledge. We
propose a multi-layer planner that first solves a simplified version of the problem at hand, to
then inform the search for a solution in the constrained space.
Our contributions on efficient motion synthesis via behaviour guidance augment the robots’
capabilities to deal with more complex planning problems, and do so more effectively than
related approaches in the literature by computing better quality paths in lower response time.
We demonstrate our contributions, in both laboratory experiments and field trials, on a
spectrum of planning problems and robotic platforms ranging from high-dimensional
humanoids and robotic arms with a focus on autonomous manipulation in resembling
environments, to high-dimensional kinematic motion planning with a focus on autonomous safe navigation in unknown environments. While this thesis was motivated by challenges on motion
synthesis, we have explored the applicability of our findings on disparate robotic fields, such as
grasp and task planning. We have made some of our contributions open-source hoping they
will be of use to the robotics community at large.The CDT in Robotics and Autonomous Systems at Heriot-Watt University and The University of EdinburghThe ORCA Hub EPSRC project (EP/R026173/1)The Scottish Informatics and Computer Science
Alliance (SICSA
The augmented reality framework : an approach to the rapid creation of mixed reality environments and testing scenarios
Debugging errors during real-world testing of remote platforms can be time consuming and expensive
when the remote environment is inaccessible and hazardous such as deep-sea. Pre-real world testing
facilities, such as Hardware-In-the-Loop (HIL), are often not available due to the time and expense
necessary to create them. Testing facilities tend to be monolithic in structure and thus inflexible
making complete redesign necessary for slightly different uses. Redesign is simpler in the short term
than creating the required architecture for a generic facility. This leads to expensive facilities, due
to reinvention of the wheel, or worse, no testing facilities. Without adequate pre-real world testing,
integration errors can go undetected until real world testing where they are more costly to diagnose
and rectify, e.g. especially when developing Unmanned Underwater Vehicles (UUVs).
This thesis introduces a novel framework, the Augmented Reality Framework (ARF), for rapid
construction of virtual environments for Augmented Reality tasks such as Pure Simulation, HIL,
Hybrid Simulation and real world testing. ARF’s architecture is based on JavaBeans and is therefore
inherently generic, flexible and extendable. The aim is to increase the performance of constructing,
reconfiguring and extending virtual environments, and consequently enable more mature and stable
systems to be developed in less time due to previously undetectable faults being diagnosed earlier in
the pre-real-world testing phase. This is only achievable if test harnesses can be created quickly and
easily, which in turn allows the developer to visualise more system feedback making faults easier to
spot. Early fault detection and less wasted real world testing leads to a more mature, stable and
less expensive system.
ARF provides guidance on how to connect and configure user made components, allowing for
rapid prototyping and complex virtual environments to be created quickly and easily. In essence,
ARF tries to provide intuitive construction guidance which is similar in nature to LEGOR
pieces
which can be so easily connected to form useful configurations.
ARF is demonstrated through case studies which show the flexibility and applicability of ARF to
testing techniques such as HIL for UUVs. In addition, an informal study was carried out to asses the
performance increases attributable to ARF’s core concepts. In comparison to classical programming
methods ARF’s average performance increase was close to 200%. The study showed that ARF was
incredibly intuitive since the test subjects were novices in ARF but experts in programming. ARF
provides key contributions in the field of HIL testing of remote systems by providing more accessible
facilities that allow new or modified testing scenarios to be created where it might not have been
feasible to do so before. In turn this leads to early detection of faults which in some cases would not
have ever been detected before
Underwater Vehicles
For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties
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