16,380 research outputs found
Robust Motion Planning employing Signal Temporal Logic
Motion planning classically concerns the problem of accomplishing a goal
configuration while avoiding obstacles. However, the need for more
sophisticated motion planning methodologies, taking temporal aspects into
account, has emerged. To address this issue, temporal logics have recently been
used to formulate such advanced specifications. This paper will consider Signal
Temporal Logic in combination with Model Predictive Control. A robustness
metric, called Discrete Average Space Robustness, is introduced and used to
maximize the satisfaction of specifications which results in a natural
robustness against noise. The comprised optimization problem is convex and
formulated as a Linear Program.Comment: 6 page
Decentralized Abstractions and Timed Constrained Planning of a General Class of Coupled Multi-Agent Systems
This paper presents a fully automated procedure for controller synthesis for
a general class of multi-agent systems under coupling constraints. Each agent
is modeled with dynamics consisting of two terms: the first one models the
coupling constraints and the other one is an additional bounded control input.
We aim to design these inputs so that each agent meets an individual high-level
specification given as a Metric Interval Temporal Logic (MITL). Furthermore,
the connectivity of the initially connected agents, is required to be
maintained. First, assuming a polyhedral partition of the workspace, a novel
decentralized abstraction that provides controllers for each agent that
guarantee the transition between different regions is designed. The controllers
are the solution of a Robust Optimal Control Problem (ROCP) for each agent.
Second, by utilizing techniques from formal verification, an algorithm that
computes the individual runs which provably satisfy the high-level tasks is
provided. Finally, simulation results conducted in MATLAB environment verify
the performance of the proposed framework
Robust Model Predictive Control for Signal Temporal Logic Synthesis
Most automated systems operate in uncertain or adversarial conditions, and have to be capable of reliably reacting to changes in the environment. The focus of this paper is on automatically synthesizing reactive controllers for cyber-physical systems subject to signal temporal logic (STL) specifications. We build on recent work that encodes STL specifications as mixed integer linear constraints on the variables of a discrete-time model of the system and environment dynamics. To obtain a reactive controller, we present solutions to the worst-case model predictive control (MPC) problem using a suite of mixed integer linear programming techniques. We demonstrate the comparative effectiveness of several existing worst-case MPC techniques, when applied to the problem of control subject to temporal logic specifications; our empirical results emphasize the need to develop specialized solutions for this domain
Prescribed Performance Control Guided Policy Improvement for Satisfying Signal Temporal Logic Tasks
Signal temporal logic (STL) provides a user-friendly interface for defining
complex tasks for robotic systems. Recent efforts aim at designing control laws
or using reinforcement learning methods to find policies which guarantee
satisfaction of these tasks. While the former suffer from the trade-off between
task specification and computational complexity, the latter encounter
difficulties in exploration as the tasks become more complex and challenging to
satisfy. This paper proposes to combine the benefits of the two approaches and
use an efficient prescribed performance control (PPC) base law to guide
exploration within the reinforcement learning algorithm. The potential of the
method is demonstrated in a simulated environment through two sample
navigational tasks.Comment: This is the extended version of the paper accepted to the 2019
American Control Conference (ACC), Philadelphia (to be published
Walking-by-Logic: Signal Temporal Logic-Guided Model Predictive Control for Bipedal Locomotion Resilient to External Perturbations
This study proposes a novel planning framework based on a model predictive
control formulation that incorporates signal temporal logic (STL)
specifications for task completion guarantees and robustness quantification.
This marks the first-ever study to apply STL-guided trajectory optimization for
bipedal locomotion push recovery, where the robot experiences unexpected
disturbances. Existing recovery strategies often struggle with complex task
logic reasoning and locomotion robustness evaluation, making them susceptible
to failures caused by inappropriate recovery strategies or insufficient
robustness. To address this issue, the STL-guided framework generates optimal
and safe recovery trajectories that simultaneously satisfy the task
specification and maximize the locomotion robustness. Our framework outperforms
a state-of-the-art locomotion controller in a high-fidelity dynamic simulation,
especially in scenarios involving crossed-leg maneuvers. Furthermore, it
demonstrates versatility in tasks such as locomotion on stepping stones, where
the robot must select from a set of disjointed footholds to maneuver
successfully
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