14 research outputs found
Parallelizing Synthesis from Temporal Logic Specifications by Identifying Equicontrollable States
For the synthesis of correct-by-construction control policies from temporal logic specifications the scalability of the synthesis algorithms is often a bottleneck. In this paper, we parallelize synthesis from specifications in the GR(1) fragment of linear temporal logic by introducing a hierarchical procedure that allows decoupling of the fixpoint computations. The state space is partitioned into equicontrollable sets using solutions to parametrized games that arise from decomposing the original GR(1) game into smaller reachability-persistence games. Following the partitioning, another synthesis problem is formulated for composing the strategies from the decomposed reachability games. The formulation guarantees that composing the synthesized controllers ensures satisfaction of the given GR(1) property. Experiments with robot planning problems demonstrate good performance of the approach
Linear Temporal Logic-based Mission Planning
In this paper, we describe the Linear Temporal
Logic-based reactive motion planning. We address the problem of
motion planning for mobile robots, wherein the goal specification
of planning is given in complex environments. The desired task
specification may consist of complex behaviors of the robot,
including specifications for environment constraints, need of task
optimality, obstacle avoidance, rescue specifications, surveillance
specifications, safety specifications, etc. We use Linear Temporal
Logic to give a representation for such complex task specification
and constraints. The specifications are used by a verification engine
to judge the feasibility and suitability of plans. The planner gives a
motion strategy as output. Finally a controller is used to generate
the desired trajectory to achieve such a goal. The approach is
tested using simulations on the LTLMoP mission planning tool,
operating over the Robot Operating System. Simulation results
generated using high level planners and low level controllers work
simultaneously for mission planning and controlling the physical
behavior of the robot
Cross-entropy Temporal Logic Motion Planning
This paper presents a method for optimal trajectory generation for discrete-time nonlinear systems with linear temporal logic (LTL) task specifications. Our approach is based on recent advances in stochastic optimization algorithms for optimal trajectory generation. These methods rely on estimation of the rare event of sampling optimal trajectories, which is achieved by incrementally improving a sampling distribution so as to minimize the cross-entropy. A key component of these stochastic optimization algorithms is determining whether or not a trajectory is collision-free. We generalize this collision checking to efficiently verify whether or not a trajectory satisfies a LTL formula. Interestingly, this verification can be done in time polynomial in the length of the LTL formula and the trajectory. We also propose a method for efficiently re-using parts of trajectories that only partially satisfy the specification, instead of simply discarding the entire sample. Our approach is demonstrated through numerical experiments involving Dubins car and a generic point-mass model subject to complex temporal logic task specifications
Reachability-based Identification, Analysis, and Control Synthesis of Robot Systems
We introduce reachability analysis for the formal examination of robots. We
propose a novel identification method, which preserves reachset conformance of
linear systems. We additionally propose a simultaneous identification and
control synthesis scheme to obtain optimal controllers with formal guarantees.
In a case study, we examine the effectiveness of using reachability analysis to
synthesize a state-feedback controller, a velocity observer, and an output
feedback controller.Comment: This work has been submitted to the IEEE for possible publication.
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Parallelizing Synthesis from Temporal Logic Specifications by Identifying Equicontrollable States
For the synthesis of correct-by-construction control policies from temporal logic specifications the scalability of the synthesis algorithms is often a bottleneck. In this paper, we parallelize synthesis from specifications in the GR(1) fragment of linear temporal logic by introducing a hierarchical procedure that allows decoupling of the fixpoint computations. The state space is partitioned into equicontrollable sets using solutions to parametrized games that arise from decomposing the original GR(1) game into smaller reachability-persistence games. Following the partitioning, another synthesis problem is formulated for composing the strategies from the decomposed reachability games. The formulation guarantees that composing the synthesized controllers ensures satisfaction of the given GR(1) property. Experiments with robot planning problems demonstrate good performance of the approach