Hybrid control of multi-robot systems using embedded graph grammars

Guo, Meng; Egerstedt, Magnus; Dimarogonas, Dimos V.

doi:10.1109/icra.2016.7487733

Cited by 8 publications

(4 citation statements)

References 22 publications

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“…In most of these problems, the property of interest is connectivity of the communication network as this allows reliable delivery of information between any pair of robots. Approaches that ensure connectivity for all time either maintain all initial communication links between the robots provided that the initial communication network is connected [14], [19]- [21], or allow for addition and removal of communication links while ensuring that the connectivity requirement is not violated [15]- [18], [22], [23]. Realistic communication models have recently been proposed in [24]- [26] that take into account path loss, shadowing, and multipath fading.…”

Section: Introductionmentioning

confidence: 99%

Multirobot Data Gathering Under Buffer Constraints and Intermittent Communication

Guo

Zavlanos

2018

IEEE Trans. Robot.

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We consider a team of heterogeneous robots which are deployed within a common workspace to gather different types of data. The robots have different roles due to different capabilities: some gather data from the workspace (source robots) and others receive data from source robots and upload them to a data center (relay robots). The data-gathering tasks are specified locally to each source robot as high-level Linear Temporal Logic (LTL) formulas, that capture the different types of data that need to be gathered at different regions of interest. All robots have a limited buffer to store the data. Thus the data gathered by source robots should be transferred to relay robots before their buffers overflow, respecting at the same time limited communication range for all robots. The main contribution of this work is a distributed motion coordination and intermittent communication scheme that guarantees the satisfaction of all local tasks, while obeying the above constraints. The robot motion and inter-robot communication are closely coupled and coordinated during run time by scheduling intermittent meeting events to facilitate the local plan execution. We present both numerical simulations and experimental studies to demonstrate the advantages of the proposed method over existing approaches that predominantly require all-time network connectivity. of data-gathering actions. The work in [34] considers a single robot transferring data between locations. The proposed approach minimizes the time interval between two consecutive data-uploading time instants. But it does not explicitly model the evolution of the robot's buffer or the inter-robot communication. Similar buffer constraints are considered in [35] for multi-robot frontier-based exploration. However locallyassigned data-gathering tasks described by LTL formulas are not considered there, nor are communication constraints. Another related area is temporal logic task planning under resource constraints. The work in [36] considers a global surveillance task performed by multiple aerial vehicles subject to battery charging constraints. The multi-vehicle routing problem considered in [37] proposes a solution based on Mixed-Integer Linear Programming (MILP), which can potentially be extended to include resource constraints.The main contribution of this work lies in the development of an online distributed framework that jointly controls local data-gathering tasks and data transfer communication events, so that the buffers at every robot never overflow. The proposed framework guarantees the satisfaction of all local tasks specified as LTL formulas, without imposing all-time connectivity on the communication network. The efficiency of the proposed framework compared to a centralized approach and two static approaches is demonstrated via numerical simulations and experimental studies. To the best of our knowledge, this is the first distributed data-gathering framework under intermittent communication that is also online. This work is built on preliminary results presented in...

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Section: Introductionmentioning

confidence: 99%

Multirobot Data Gathering Under Buffer Constraints and Intermittent Communication

Guo

Zavlanos

2018

IEEE Trans. Robot.

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“…Definition 3. 6 An L/R application to graph 𝐺 is a process that generates graph 𝐻 ′ using production 𝑝: 𝐺 ̅ 𝐿 ≔ 𝐺 ̅ 𝑅 , denoted as 𝐺 → 𝑝 𝐺 ′ (L-application) or 𝐺 ↦ 𝑝 𝐺 ′ (R-application), where 𝑄 ̅ ∈ 𝑅𝑒𝑑𝑒𝑥(𝐺, 𝐺 ̅ 𝐿|𝑅 ) and 𝐶𝑜𝑟𝑒(𝐺 ̅ 𝑅|𝐿 ) is used to replace Core(𝑄 ̅ ) in 𝐺.…”

Section: ∀𝑛((𝑛 ∈ 𝑄) ∧ ((𝑛 𝐸 ̇= 𝛷) ⋁( ∀𝑒̇((𝑒̇∈ 𝑛 𝐸 ̇) ∧ (𝑓 𝐸𝑀 (𝑒) ∉ 𝑀 ...mentioning

confidence: 99%

“…Originally developed from string-based formal languages, graph grammar is a two-dimensional formal method that is used for graph generation and parsing by derivation and reduction. Graph grammars have been used in many applications [1][2][3][4][5][6][7][8], such as web pattern specification [1] and validation of floor plans [2]. However, most graph grammars focus on the specification of abstract graphs and ignore the specification of the physical layouts of graphs.…”

Section: Introductionmentioning

confidence: 99%

An enhanced grammatical approach for graph drawing

Liu

Zhou²,

Yang³

2023

International Conference on Artificial Intelligence, Virtual Reality, and Visualization (AIVRV 2022)

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With the development of computer-aided design, visual languages have been widely used as formal methods to represent various types of graphical models. Accordingly, many grammar systems have been proposed for the specification of visual languages. However, apart from shape grammar, most grammars focus on the abstract structures of the languages and ignore the semantic modeling of graph drawing. Furthermore, shape grammar supports generation rather than parsing, with its limited application scope. To address these problems, this paper proposes an enhanced grammar system based on Coordinate Graph Grammar (CGG). Different from traditional grammars, the enhanced system defines a new type of grammatical rule named shape rules to transform graphs into shapes by shape applications. In each shape application, the assertion set describes the range of validity, and shapes can be generated by translation, zoom, and rotation to a set of rulebased coordinates. With the combinations of shape applications and L-applications, the node-edge graph and drawn outline could both be specified, building a bridge between abstract structures and physical layouts of visual languages. An example is given to illustrate the application of the enhanced system in industrial design, where a Bauhaus-style baby cradle is generated by the combination of shape applications and L-applications.

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“…Emails: meng.guo, michael.zavlanos@duke.edu. This work is supported in part by NSF under grant IIS #1302283. and actions in the task specification [6] and partially-known or dynamic workspaces in [7], [8].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Motion Planning Under Temporal Tasks and Soft Constraints

Guo

Zavlanos

2018

IEEE Trans. Automat. Contr.

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This paper studies motion planning of a mobile robot under uncertainty. The control objective is to synthesize a finite-memory control policy, such that a high-level task specified as a Linear Temporal Logic (LTL) formula is satisfied with a desired high probability. Uncertainty is considered in the workspace properties, robot actions, and task outcomes, giving rise to a Markov Decision Process (MDP) that models the proposed system. Different from most existing methods, we consider cost optimization both in the prefix and suffix of the system trajectory. We also analyze the potential trade-off between reducing the mean total cost and maximizing the probability that the task is satisfied. The proposed solution is based on formulating two coupled Linear Programs, for the prefix and suffix, respectively, and combining them into a multi-objective optimization problem, which provides provable guarantees on the probabilistic satisfiability and the total cost optimality. We show that our method outperforms relevant approaches that employ Round-Robin policies in the trajectory suffix. Furthermore, we propose a new control synthesis algorithm to minimize the frequency of reaching a bad state when the probability of satisfying the tasks is zero, in which case most existing methods return no solution. We validate the above schemes via both numerical simulations and experimental studies.

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Hybrid control of multi-robot systems using embedded graph grammars

Cited by 8 publications

References 22 publications

Multirobot Data Gathering Under Buffer Constraints and Intermittent Communication

Multirobot Data Gathering Under Buffer Constraints and Intermittent Communication

An enhanced grammatical approach for graph drawing

Probabilistic Motion Planning Under Temporal Tasks and Soft Constraints

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