https://roboticpatterns.com/tags/avoidance/ Recent content in avoidance on Specification Patterns for Robotic Missions Hugo -- gohugo.io en-us Claudio Menghi, Christos Tsigkanos, Thorsten Berger, Patrizio Pelliccione, Carlo Ghezzi Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/exactrestrictedavoidance/ Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/exactrestrictedavoidance/ Intent It specifies that a robot should avoid visiting a location a number of times that is different from “n”, i.e., the robot should visit a location exactly “n” times LTL Template $\underbrace{(\neg (l1)) \mathcal{U} (l1 \wedge (\mathcal{X} ((\neg l1) \mathcal{U} (l1 \ldots \wedge (\mathcal{X} ((\neg l1) \mathcal{U} (l1}_\text{n}$ $ \wedge (\mathcal{X} (\mathcal{G} (\neg l1))))))))))$, where $l_1 \in L$ Note that the pattern is general and consider the case in which a robot can be in two locations at the same time. https://roboticpatterns.com/pattern/futureavoidance/ Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/futureavoidance/ Intent Specifies that a condition will be avoided in the future. LTL Template $\mathcal{G}( (c) \rightarrow( \mathcal{G} (\neg (l_1))))$, where $c \in M$ and $l_1 \in PL$ Examples and Known Uses If the robot enters $l_1$, then it should avoid entering $l_2$ in the future. The trace $l_3 \rightarrow l_4 \rightarrow l_3 \rightarrow l_1 \rightarrow l_4 \rightarrow l_3 \rightarrow ( l_3 \rightarrow l_2 \rightarrow l_3)^\omega$ does not satisfy the mission requirement since $l_2$ is entered after $l_1$. https://roboticpatterns.com/pattern/globalavoidance/ Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/globalavoidance/ Intent Specifies that an avoidance condition globally holds. LTL Template $\mathcal{G}(\neg (l_1))$, where $l_1 \in L$ Examples and Known Uses The robot should avoid entering location $l_1$. Trace $l_3 \rightarrow l_4 \rightarrow l_3 \rightarrow l_2 \rightarrow l_4 \rightarrow l_3 \rightarrow ( l_3 \rightarrow l_2 \rightarrow l_3)^\omega$, satisfies the mission requirement since the robot never enters $l_1$. Relationships Global avoidance is a specific instance of the Avoidance patterns requiring a location to be always avoided. https://roboticpatterns.com/pattern/lowerrestrictedavoidance/ Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/lowerrestrictedavoidance/ Intent Applies when a restriction on the minimum number of occurrences is desired. LTL Template $\mathcal{F} (\underbrace{l_1 \wedge \mathcal{X} (\mathcal{F}(l_1 \wedge \ldots \mathcal{X} (\mathcal{F}(l_1)}_\text{n})))) $, where $l_1 \in L$ Examples and Known Uses A robot to enter location $l_1$ at least $3$ times. The trace $l_4 \rightarrow l_3 \rightarrow l_2 \rightarrow l_2\rightarrow l_4 \rightarrow ( l_3)^\omega$ violates the mission requirement since location $1$ is never entered. The trace $l_1 \rightarrow l_4 \rightarrow l_3 \rightarrow l_1 \rightarrow l_4 \rightarrow l_1 \rightarrow ( l_3)^\omega$ satisfies the mission requirement. https://roboticpatterns.com/pattern/upperrestrictedavoidance/ Thu, 08 Feb 2018 17:51:49 +0100 https://roboticpatterns.com/pattern/upperrestrictedavoidance/ Intent Applied when a restriction on the maximum number of occurrences is desired. LTL Template $\neg \mathcal{F} (\underbrace{l_1 \wedge \mathcal{X} (\mathcal{F}(l_1 \wedge \ldots \mathcal{X} (\mathcal{F}(l_1)}_\text{n})))) $, where $l_1 \in L$ Note that the pattern is general and consider the case in which a robot can be in two locations at the same time. For example, a robot can be in an area of a building indicated as l1 (e.