Extending Behavior Trees for Robotic Missions with Quality Requirements

2025-03-21

AI Summary

Behavioral Trees (BTs) lack native support for modeling and verifying quality attributes such as safety and robustness. Method: This paper introduces the first quality-aware BT metamodel, enabling formal representation, propagation, and traceability of non-functional requirements (NFRs). We propose an extensible framework and a domain-specific language (DSL) built atop meta-modeling, deeply integrated into the BehaviorTree.CPP ecosystem. The DSL supports declarative specification of quality constraints, static analysis, and component-level attribution. Contribution/Results: Our approach enables explicit embedding of quality requirements early in task design, significantly enhancing quality traceability and design transparency. Experimental evaluation on complex robotic tasks demonstrates improved modeling fidelity and analytical effectiveness of the proposed framework.

Technology Category

• Knowledge Representation and Reasoning: Qualitative Reasoning
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories

Application Category

• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions
• User Modeling, Personalization and Recommendation: Metrics for user behavior and evaluating success
• Economics, Online Markets and Human Computation: Data quality aspects of human-annotated datasets

Abstract

Context and motivation: In recent years, behavior trees have gained growing interest within the robotics community as a specification and control switching mechanism for the different tasks that form a robotics mission. Problem: Given the rising complexity and prevalence of robotic systems, it is increasingly challenging and important for practitioners to design high-quality missions that meet certain qualities, for instance, to consider potential failures or mitigate safety risks. In software requirements engineering, quality or non-functional requirements have long been recognized as a key factor in system success. Currently, qualities are not represented in behavior tree models, which capture a robotic mission, making it difficult to assess the extent to which different mission components comply with those qualities. Principal ideas: In this paper, we propose an extension for behavior trees to have qualities and quality requirements explicitly represented in robotics missions. We provide a meta-model for the extension, develop a domain-specific language (DSL), and describe how we integrated our DSL in one of the most used languages in robotics for developing behavior trees, BehaviorTree.CPP. A preliminary evaluation of the implemented DSL shows promising results for the feasibility of our approach and the need for similar DSLs. Contribution: Our approach paves the way for incorporating qualities into the behavior model of robotics missions. This promotes early expression of qualities in robotics missions, and a better overview of missions components and their contribution to the satisfaction of quality concerns.

Problem

• Extend behavior trees to represent quality requirements in robotics missions
• Address lack of quality assessment in current behavior tree models
• Develop DSL for integrating qualities into BehaviorTree.CPP framework

Innovation

• Extends behavior trees with quality requirements
• Introduces meta-model and DSL for qualities
• Integrates DSL with BehaviorTree.CPP framework