1,485 research outputs found
Online Inverse Optimal Control for Control-Constrained Discrete-Time Systems on Finite and Infinite Horizons
In this paper, we consider the problem of computing parameters of an
objective function for a discrete-time optimal control problem from state and
control trajectories with active control constraints. We propose a novel method
of inverse optimal control that has a computationally efficient online form in
which pairs of states and controls from given state and control trajectories
are processed sequentially without being stored or processed in batches. We
establish conditions guaranteeing the uniqueness of the objective-function
parameters computed by our proposed method from trajectories with active
control constraints. We illustrate our proposed method in simulation.Comment: 10 pages, 4 figures, Accepted for publication in Automatic
A Rapidly Deployable Classification System using Visual Data for the Application of Precision Weed Management
In this work we demonstrate a rapidly deployable weed classification system
that uses visual data to enable autonomous precision weeding without making
prior assumptions about which weed species are present in a given field.
Previous work in this area relies on having prior knowledge of the weed species
present in the field. This assumption cannot always hold true for every field,
and thus limits the use of weed classification systems based on this
assumption. In this work, we obviate this assumption and introduce a rapidly
deployable approach able to operate on any field without any weed species
assumptions prior to deployment. We present a three stage pipeline for the
implementation of our weed classification system consisting of initial field
surveillance, offline processing and selective labelling, and automated
precision weeding. The key characteristic of our approach is the combination of
plant clustering and selective labelling which is what enables our system to
operate without prior weed species knowledge. Testing using field data we are
able to label 12.3 times fewer images than traditional full labelling whilst
reducing classification accuracy by only 14%.Comment: 36 pages, 14 figures, published Computers and Electronics in
Agriculture Vol. 14
Autonomous Sweet Pepper Harvesting for Protected Cropping Systems
In this letter, we present a new robotic harvester (Harvey) that can
autonomously harvest sweet pepper in protected cropping environments. Our
approach combines effective vision algorithms with a novel end-effector design
to enable successful harvesting of sweet peppers. Initial field trials in
protected cropping environments, with two cultivar, demonstrate the efficacy of
this approach achieving a 46% success rate for unmodified crop, and 58% for
modified crop. Furthermore, for the more favourable cultivar we were also able
to detach 90% of sweet peppers, indicating that improvements in the grasping
success rate would result in greatly improved harvesting performance
Strategies for pre-emptive mid-air collision avoidance in Budgerigars
We have investigated how birds avoid mid-air collisions during head-on encounters. Trajectories of birds flying towards each other in a tunnel were recorded using high speed video cameras. Analysis and modelling of the data suggest two simple strategies for collision avoidance: (a) each bird veers to its right and (b) each bird changes its altitude relative to the other bird according to a preset preference. Both strategies suggest simple rules by which collisions can be avoided in head-on encounters by two agents, be they animals or machines. The findings are potentially applicable to the design of guidance algorithms for automated collision avoidance on aircraft
Unmanned aerial surveillance system for hazard collision avoidance in autonomous shipping
Autonomous ships require a sense-andcollision- avoidance functionality based on surveillance of the ocean surface in order to detect unmapped and potentially non-cooperative obstacles and hazards, and to engage into evasive manoeuvres to avoid impending collisions. In this paper, we study the concept of using an autonomous ship being assisted by an unmanned aerial surveillance system (UASS) that provides information to the ship in order to implement collision avoidance in compliance with the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS). The motivation is that a UASS provides complementary sensing capabilities that can be combined with a conventional maritime radar and Automatic Identification System (AIS) to detect smaller obstacles that may be hidden in clutter, behind other objects, or submerged close to the surface. We propose a system architecture and implement a simulation environment to illustrate the concept and study the feasibility of the key control algorithms based on receding-horizon optimization
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