4,774 research outputs found
Extended LTLvis Motion Planning interface (Extended Technical Report)
This paper introduces an extended version of the Linear Temporal Logic (LTL)
graphical interface. It is a sketch based interface built on the Android
platform which makes the LTL control interface more straightforward and
friendly to nonexpert users. By predefining a set of areas of interest, this
interface can quickly and efficiently create plans that satisfy extended plan
goals in LTL. The interface can also allow users to customize the paths for
this plan by sketching a set of reference trajectories. Given the custom paths
by the user, the LTL specification and the environment, the interface generates
a plan balancing the customized paths and the LTL specifications. We also show
experimental results with the implemented interface.Comment: 8 pages, 15 figures, a technical report for the 2016 IEEE
International Conference on Systems, Man, and Cybernetics (SMC 2016
Synthesis of Distributed Longitudinal Control Protocols for a Platoon of Autonomous Vehicles
We develop a framework for control protocol synthesis for a platoon of autonomous vehicles subject to temporal logic specifications. We describe the desired behavior of the platoon in a set of linear temporal logic formulas, such as collision avoidance, close spacing or comfortability. The problem of decomposing a global specification for the platoon into distributed specification for each pair of adjacent vehicles is hard to solve. We use the invariant specifications to tackle this problem and the decomposition is proved to be scalable.. Based on the specifications in Assumption/Guarantee form, we can construct a two-player game (between the vehicle and its closest leader) locally to automatically synthesize a controller protocol for each vehicle. Simulation example for a distributed vehicles control problem is also shown
Synthesis of Switching Protocols from Temporal Logic Specifications
We propose formal means for synthesizing switching protocols that determine the sequence in which the modes of a switched system are activated to satisfy certain high-level specifications in linear temporal logic. The synthesized protocols are robust against exogenous disturbances on the continuous dynamics. Two types of finite transition systems, namely under- and over-approximations, that abstract the behavior of the underlying continuous dynamics are defined. In particular, we show that the discrete synthesis problem for an under-approximation can be formulated as a model checking problem, whereas that for an over-approximation can be transformed into a two-player game. Both of these formulations are amenable to efficient, off-the-shelf software tools. By construction, existence of a discrete switching strategy for the discrete synthesis problem guarantees the existence of a continuous switching protocol for the continuous synthesis problem, which can be implemented at the continuous level to ensure the correctness of the nonlinear switched system. Moreover, the proposed framework can be straightforwardly extended to accommodate specifications that require reacting to possibly adversarial external events. Finally, these results are illustrated using three examples from different application domains
LTL Control in Uncertain Environments with Probabilistic Satisfaction Guarantees
We present a method to generate a robot control strategy that maximizes the
probability to accomplish a task. The task is given as a Linear Temporal Logic
(LTL) formula over a set of properties that can be satisfied at the regions of
a partitioned environment. We assume that the probabilities with which the
properties are satisfied at the regions are known, and the robot can determine
the truth value of a proposition only at the current region. Motivated by
several results on partitioned-based abstractions, we assume that the motion is
performed on a graph. To account for noisy sensors and actuators, we assume
that a control action enables several transitions with known probabilities. We
show that this problem can be reduced to the problem of generating a control
policy for a Markov Decision Process (MDP) such that the probability of
satisfying an LTL formula over its states is maximized. We provide a complete
solution for the latter problem that builds on existing results from
probabilistic model checking. We include an illustrative case study.Comment: Technical Report accompanying IFAC 201
Specification Patterns for Robotic Missions
Mobile and general-purpose robots increasingly support our everyday life,
requiring dependable robotics control software. Creating such software mainly
amounts to implementing their complex behaviors known as missions. Recognizing
the need, a large number of domain-specific specification languages has been
proposed. These, in addition to traditional logical languages, allow the use of
formally specified missions for synthesis, verification, simulation, or guiding
the implementation. For instance, the logical language LTL is commonly used by
experts to specify missions, as an input for planners, which synthesize the
behavior a robot should have. Unfortunately, domain-specific languages are
usually tied to specific robot models, while logical languages such as LTL are
difficult to use by non-experts. We present a catalog of 22 mission
specification patterns for mobile robots, together with tooling for
instantiating, composing, and compiling the patterns to create mission
specifications. The patterns provide solutions for recurrent specification
problems, each of which detailing the usage intent, known uses, relationships
to other patterns, and---most importantly---a template mission specification in
temporal logic. Our tooling produces specifications expressed in the LTL and
CTL temporal logics to be used by planners, simulators, or model checkers. The
patterns originate from 245 realistic textual mission requirements extracted
from the robotics literature, and they are evaluated upon a total of 441
real-world mission requirements and 1251 mission specifications. Five of these
reflect scenarios we defined with two well-known industrial partners developing
human-size robots. We validated our patterns' correctness with simulators and
two real robots
Decentralized Motion Planning with Collision Avoidance for a Team of UAVs under High Level Goals
This paper addresses the motion planning problem for a team of aerial agents
under high level goals. We propose a hybrid control strategy that guarantees
the accomplishment of each agent's local goal specification, which is given as
a temporal logic formula, while guaranteeing inter-agent collision avoidance.
In particular, by defining 3-D spheres that bound the agents' volume, we extend
previous work on decentralized navigation functions and propose control laws
that navigate the agents among predefined regions of interest of the workspace
while avoiding collision with each other. This allows us to abstract the motion
of the agents as finite transition systems and, by employing standard formal
verification techniques, to derive a high-level control algorithm that
satisfies the agents' specifications. Simulation and experimental results with
quadrotors verify the validity of the proposed method.Comment: Submitted to the IEEE International Conference on Robotics and
Automation (ICRA), Singapore, 201
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