CAREER: Safe Autonomy for Soft Robots

由软橡胶材料制成的机器人可以在刚性机器人无法与人类密切合作的环境中与人类密切合作，因为无意的接触会造成更少的伤害。然而，希望软机器人在人类周围更安全的想法忽略了机器人的任务可能是多方面的，以及安全性如何依赖于比减少意外力更多的东西。例如，辅助医疗程序的软机器人臂必须满足对患者身体的过大压力和不足压力以及其动作的定时和顺序的约束。这个教师早期职业发展（CAREER）项目支持旨在开发自主人工智能系统的研究，该系统使软机器人在可验证的安全运动过程中与人类密切接触，无论安全性如何定义。该项目的新奇在于首次将结构安全控制应用于软机器人，并专注于其中的独特挑战，例如机器人的可控刚性，缺乏高度精确的数学模型以及随着时间的推移对机器人的改变。该项目的影响在于有可能使普通医疗程序成本低且广泛可及，同时减少临床医生对患者舒适度和疼痛耐受性的主观决定所产生的偏见。为了减少这些偏见，该项目正在将研究与教育结合起来，开展一项众包公民科学活动。该活动要求高中生构建自己的软体机器人，并为自己定义其安全限制，并将他们的结果与其他人进行比较，以便我们最终回答：是什么使软体机器人安全，对谁安全？该项目重新定义的控制软机器人作为一个规范的满意度问题，而不是运动跟踪，通过寻求初步的答案，三个研究问题：（RQ 1）体现智能的软材料是否有助于软机器人机械手在满足安全约束，或减损其能力，这样做，在什么条件下？(RQ2)控制策略中的哪些权衡可以平衡软操纵器的固有顺应性（在未知环境中有用）与安全约束的严格性（在环境明确定义时有用）？(RQ3)什么样的安全自主的合成技术可以表达一个软机器人手臂在不确定的接触过程中与人类成功的任务转换？为此，该项目追求相应的创新，有三个研究目标：（RO 1）通过控制障碍函数和基于优化的监督控制，为软机器人手臂开发安全验证的反馈系统，满足位置，速度和力的约束。(RO2)扩展这个框架的控制软机器人的刚度，开发一个新的调解/deconfliction系统，用于验证安全裕度下多个可能随时间变化的软动力学模型。(RO3)在与人体组织模拟物接触期间，将时间逻辑和自动机用于软机器人在硬件中的安全任务转换。该项目为控制和软机器人之间关系的重新概念化奠定了基础，使具身智能与人工智能相协调可能会克服人类与机器人接触的根本限制。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Robots built from soft rubbery materials could work closely with humans in settings where rigid robots cannot, since unintentional contact would cause fewer injuries. However, the hope that soft robots are safer around humans neglects how multi-faceted the robot’s tasks may be, and how safety depends on much more than reducing accidental forces. For example, a soft robotic arm assisting in a medical procedure must meet constraints on both too much pressure as well as not enough pressure on a patient’s body, as well as timing and in sequencing of its actions. This Faculty Early Career Development (CAREER) project supports research aimed at developing autonomous artificial intelligence systems that bring a soft robot into close contact with humans during verifiably-safe motion, no matter how safety is defined. The project’s novelty is the first application of safe-by-construction control to soft robots, as well as the focus on unique challenges therein such as controllable stiffening of the robot, lack of highly accurate mathematical models, and changes to the robot over time. This project’s impacts are in the potential to make common medical procedures low-cost and widely accessible, while reducing biases arising from subjective clinician decisions about patient comfort and pain tolerance. To reduce these biases, the project is integrating research with education for a crowdsourced citizen science activity. The activity asks high school students to construct their own soft robot and define its safety limits for themselves, and compare their results with others so that we may ultimately answer: what makes a soft robot safe, and for whom?This project reframes the control of soft robots as a specification satisfaction problem, rather than motion tracking, by seeking initial answers to three research questions: (RQ1) Does the embodied intelligence of soft materials assist a soft robot manipulator in meeting a safety constraint, or detract from its ability to do so, and under what conditions? (RQ2) What tradeoffs in control strategies can balance the inherent compliance of a soft manipulator, useful in unknown environments, with strictness in safety constraints, useful when an environment is well-defined? (RQ3) What synthesis techniques for safe autonomy could express successful task transitions of a soft robot arm during uncertain contact with a human? To do so, the project pursues corresponding innovations with three research objectives: (RO1) Develop safety-verified feedback systems for a soft robotic arm, meeting constraints on position, velocity, and force, via control barrier functions and optimization-based supervisory control. (RO2) Extend this framework for control of the soft robot’s stiffness, developing a new mediation/deconfliction system for verifying safety margins under multiple possibly-time-varying soft dynamics models. (RO3) Validate the use of temporal logic and automata for safe task transitions of a soft robot in hardware, during contact with a human tissue analog. Together, this project sets a baseline for reconceptualizing the relationship between control and soft robots, with the possibility that harmonizing embodied intelligence with artificial intelligence may overcome fundamental limitations in human-robot contact.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.