Collaborative Research: Single-Input Control of Large Microrobot Swarms using Serial Addressing for Microassembly and Biomedical Applications

这个合作研究项目将为大型微型机器人群创造一个实用的控制方案。这些机器人通常长度不超过几毫米，依靠外部电源和控制信号。目前，有可能将蜂群作为一个整体引导到一个目的地（或者可能是一个期望的平均位置）。然而，要实现微型机器人群的全部潜在好处，就需要能够同时向单个机器人或小群机器人发送独立命令。先前已经探索了响应不同指令幅度的设备设计，但是随着可独立寻址的机器人数量的增加，这种方法很快变得不切实际。这种可伸缩性问题可以通过使用串行寻址方案来克服。这里，控制信号只有几个不同的值。每个可独立寻址的机器人子集都与一个唯一的信号值序列相关联，并且只有当控制信号包含该特定序列时才会改变其行为。本项目考虑了在实施这种方案时出现的两个基本问题。首先是需要机载计算和内存，允许机器人识别唯一的序列，并根据检测到的序列改变机器人的状态。其次是需要一个与机器人状态耦合的推进机构，以允许向目标构型进行微分制导。该项目将推进满足这两种需求的两个创新工程平台。第一种是静电驱动的，在平面基板上操作，适用于微组装等结构化任务。第二种是磁驱动的，在液体体积中操作，适用于生物医学应用，如药物输送。该项目的技术方面得到了外展活动的赞扬，包括将在IEEE机器人与自动化国际会议上举行的年度微型机器人移动竞赛，这是学术界和工业界的首要机器人会议。该项目的成果将通过为微型机器人群提供新的诊断和治疗用途，提高国民健康水平。他们还将促进国家的繁荣，使新型微型装配机器人成为可能。本项目旨在开发一种实用的控制方案，以同时控制大量微型机器人。这将通过使用微机电系统（MEMS）对嵌入在单个全局控制信号中的序列进行机电和磁解码来实现，并将该序列的重新配置与单个微型机器人轨迹的修改相结合。这种车载序列解码将通过一组基于车载物理的有限状态机（PFSM）来完成，这些有限状态机可以接受嵌入在控制信号中的控制序列，并相应地改变微型机器人的行为。该项目将使用静电和磁性方法来实现pfsm，并将其“接受”状态与推进机制相耦合，以调节单个轨迹。一组应力工程静电开关将根据预编程的控制电压序列锁存，将用于在静电平台上实现PFSM。电磁永磁路的磁矩随磁场序列的变化而变化，将被用来实现磁平台上的PFSM。该项目将发展基于PFSM的多微机器人控制理论，构建静电和磁性微机器人PFSM平台，并通过在一群静电和磁力驱动的微机器人上实现基于PFSM的控制来验证这一概念。所开发的理论和方法将为大量生物医学和微装配应用的大型微型机器人群的控制铺平道路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This collaborative research project will create a practical control scheme for large swarms of microrobots. These robots are typically no more than a few millimeters in length, and rely on an external power source and control signal. Currently, it is possible to steer the swarm as a whole to a single destination (or perhaps, to a desired average location). However, realizing the full potential benefits of microrobot swarms will require the ability to simultaneously send independent commands, either to individual robots or to small subgroups. Device designs have previously been explored that respond to different command amplitudes, however this approach quickly becomes impractical as the number of independently addressable robots grows. This scalability problem can be overcome using serial addressing schemes. Here, there are only a few distinct values for the control signal. Each independently addressable subset of robots is associated with a unique sequence of signal values, and will change its behavior only if the control signal contains that specific sequence. This project considers two fundamental issues that arise in implementing such a scheme. First is the need for on-board computation and memory allowing the robots to recognize the unique sequence and to change the robots state based on the detection of such sequence. Second is the need for a propulsive mechanism that couples to the robot state to allow differential guidance towards a target configuration. This project will advance two innovative engineering platforms that meet both needs. The first is electrostatically actuated, operates on a planar substrate, and is suitable for structured tasks such as microassembly. The second is magnetically actuated, operates in a liquid volume, and is suitable for biomedical applications such as drug delivery. The technical aspects of the project are complimented by outreach activities, including an annual microrobotics mobility competition to be held at the IEEE International Conference on Robotics and Automation -- a premier robotics conference for academia and industry. The results from this project will enhance the national health, by enabling new diagnostic and therapeutic uses for microrobot swarms. They will also promote the national prosperity, by enabling new classes of microassembly robots.This project aims to develop a practical control scheme to simultaneously control large numbers of microrobots. This will be achieved by using microelectromechanical systems (MEMS) to electromechanically and magnetically decode a sequence embedded in the single global control signal, and couple the reconfiguration of such sequence to the modification of the individual microrobot trajectories. This on-board sequence decoding will be accomplished through sets of on-board physics-based finite state machines (PFSM) that can accept a control sequence embedded in the control signal and change the behavior of the microrobots accordingly. The project will use both electrostatic and magnetic approaches to implement PFSMs, and to couple their "accept" state to the propulsion mechanism to modulate individual trajectories. Sets of stress-engineered electrostatic switches, which will latch in response to a pre-programmed control voltage sequence, will be used to implement PFSM on the electrostatic platform. Electro-permanent magnetic circuits, which change their magnetic moment in response to a sequence of global magnetic field, will be used to implement PFSM on the magnetic platform. The project will develop the theory for PFSM-based multi-microrobot control, construct both electrostatic and magnetic microrobotic PFSM platforms, and validate the concept by implementing the PFSM-based control on swarms of electrostatically and magnetically powered microrobots. The developed theory and approach will pave way for control of large microrobot swarms for numerous biomedical and microassembly applications.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.