New motion control tools for robotics and rehabilitation

这项研究计划涉及到算法的开发，以使机器人以经过验证的稳定性执行复杂的运动。这项研究的工具基于非线性控制理论和力学。机器人曾经被降级到制造工厂的地板上，今天机器人正在我们的家庭、医院和整个社会中传播。随着机器人技术的进步，对控制算法的需求越来越大，使机器人能够安全地执行复杂的任务。如何让行走的机器人爬楼梯或跳楼？如何让像鱼一样的机器人在陆地上游泳或爬行？传统的控制机器人运动的方法是将运动控制问题分解为两个概念上独立的子问题：运动规划和轨迹跟踪。在过去的十五年里，机器人运动控制出现了一种新的范例，它能够产生惊人的自然运动和卓越的健壮性。所讨论的范式是虚拟约束的范式。其思想是通过对机器人关节的约束来隐含地表示所需的运动(例如，两足行走)。这样的约束在物理上并不存在，但它们是通过反馈控制的方式强制执行的，因此形容词“虚拟的”。虽然虚拟约束已经成为行走机器人控制的一个突出范例，但它们在机器人学其他领域的适用性在很大程度上仍有待探索。这项研究是基于这样一种猜想，即虚拟约束范式实际上适用于机器人的一大类运动控制问题，并且它是诱导高度复杂的生物启发运动的很好的候选者。*在过去的几年里，我和我的合作者发展了一种关于欠驱动度为1的机器人的虚拟约束理论，即一个执行器少于其自由度的机器人。虽然我们到目前为止取得的成果令人鼓舞，但仍有许多工作要做，这就是我目前申请探索基金的主题。我打算在接下来的五年里进行的研究主要有两个方面：理论和实验。在理论方面，我打算为欠驱动程度大于1的机器人发展一种新的虚拟约束理论。这将使虚拟约束范例在各种机器人运动问题中变得可行。在实验方面，我将与医疗康复领域的研究人员合作，调查假肢设备和外骨骼使用虚拟约束的情况。这项研究的长期目标是开发一套全面的工具，用于生物启发的机器人的高级运动控制，能够产生看起来自然的复杂运动，并具有对环境不确定性的卓越健壮性。

This research proposal concerns the development of algorithms to make robots perform complex motions with proven stability. The tools of this research are grounded in nonlinear control theory and mechanics.******Once relegated to the floors of manufacturing plants, today robots are spreading in our homes, hospitals, and the society at large. As the technology of robotics advances, there is an increasing need for control algorithms making robots perform complex tasks with proven safety. How to make a walking robot climb stairs or jump? How to make a fish-like robot swim or a snake robot crawl on land?******The traditional approach to controlling the motion of robots was to partition the motion control problem into two conceptually separate sub-problems: motion planning and trajectory tracking. Over the past fifteen years, a new paradigm has emerged for motion control of robots which is capable of producing strikingly natural motions with a superior degree of robustness. The paradigm in question is that of virtual constraints. The idea is to represent a desired motion (e.g., bipedal walking) implicitly by means of constraints on the robot joints. Such constraints do not physically exist, but they are enforced by means of feedback control, hence the adjective "virtual". While virtual constraints have come to represent a prominent paradigm for the control of walking robots, their applicability in other areas of robotics remains largely unexplored. The proposed research is driven by the conjecture that the virtual constraint paradigm is in fact applicable to a large class of motion control problems for robots, and it is a good candidate to induce biologically inspired motions of great complexity. ******Over the past few years, my collaborators and I have developed a theory of virtual constraints for robots with degree of underactuation one, i.e., robots with one actuator less than their number of degrees-of-freedom. While the results we obtained so far are encouraging, much work remains to be done, and this is the subject of my current Discovery Grant application. The research I intend to perform over the next five years has two main thrusts: theoretical and experimental. On the theoretical side, I intend to develop a new theory of virtual constraints for robots with degree of underactuation greater than one. This will allow the virtual constraint paradigm to become viable in a wide variety of robot locomotion problems. On the experimental side, I will initiate a collaborative thrust with researchers in the area of medical rehabilitation, investigating the use of virtual constraints for prosthetic devices and exoskeletons.******The long-term objective of this research is the development of a comprehensive set of tools for advanced motion control of biologically inspired robots, capable of producing complex motions that look natural, and which are endowed with a superior degree of robustness against environmental uncertainties.