Advantages of reconfigurable and variable-impedance haptic user interfaces

背景：******触觉交互是人类理解环境和影响环境变化的最基本方式。触觉反馈为操作机器（如飞机、挖掘机或加拿大臂或火星探测器等机器人）的人提供了一种触摸物体的感觉，他们实际上并没有触摸到物体，而是被机器操纵着。触觉反馈使机器操作员能够更温和、安全、可靠和精确地处理物体。******触觉界面（HIs）通过对用户的手施加力来产生触摸的错觉。HI应该有一个大的工作空间。它还应满足反驾驶性、低表观惯性和低摩擦的要求，以获得最佳的小反射力感知，以及大的内在刚度和力反馈能力，以获得最佳的大反射力感知。然后，HI可以以高保真度为用户再现软硬接触体验。******目标：******目前可用的HIs要么是具有较高力反馈能力、较高固有刚度和较小工作空间的并联机构，要么是具有较低力反馈能力、较低固有刚度和较大工作空间的串行机构。由于高力反馈能力，高固有刚度和大工作空间是理想的，因此本研究将通过适当的设计和控制（包括可变阻抗控制）冗余触觉接口（RHIs）来确保两者的最佳效果，RHIs具有比执行任务所需的最低自由度更多的自由度。******具体目标：******* SA 1：使用适当设计的RHI实现尽可能多的理想HI特性，以实现更直观和有效的用户/RHI交互。我们将研究RHIs的内在优势，这些优势可以通过机械设计获得，例如，较低的惯性和更大的工作空间（与非冗余HIs相比）。******* SA 2：利用RHIs的运动学冗余来实现次要目标，进一步优化其运动学和动力学特性。次要目标是进一步提高可操纵性、最小化表观惯性和最大化力反馈能力。通过联合级闭环控制获得的这些优势超过了在sa1中获得的固有优势。******* SA 3：根据给定任务/用户的要求，用RHI冗余分辨率和阻抗调制补充SA 1中的设计和SA 2中的控制。基于任务和用户的笛卡尔级变阻抗控制和关节级冗余分辨率将进一步提高触觉交互保真度和用户任务性能。******新颖性：******虽然对与任务环境交互的冗余机械手进行了大量研究，但对RHIs的设计和控制却很少关注。这项研究有助于创建具有增强安全性和性能的触觉交互和远程操作系统。

BACKGROUND:******Haptic interaction is the human's most basic way to understand an environment and effect change in it. Haptic feedback provides humans who operate machines (e.g., planes, excavators, or robots such as the Canadarm or Mars rovers) with a sense of touching objects they are not actually touching but are manipulating by the machines. Haptic feedback allows the human operators of machines to handle objects more gently, safely, reliably, and precisely. ******Haptic interfaces (HIs) produce the illusion of touch by applying forces to the users' hands. An HI should have a big workspace. It should also satisfy the requirements of back-drivability, low apparent inertia and low friction for the best perception of small reflected forces, and large intrinsic stiffness and force feedback capability for the best perception of large reflected forces. Then, the HI can recreate soft and stiff contact experiences for the user with high fidelity. ******OBJECTIVES:******The currently available HIs are either parallel mechanisms with higher force feedback capability, a higher intrinsic stiffness and a smaller workspace or serial mechanisms with lower force feedback capability, a lower intrinsic stiffness and a larger workspace. Since a high force feedback capability, a high intrinsic stiffness and a large workspace are desirable, this research will secure the best of both worlds by appropriate design and control (including variable-impedance control) of redundant haptic interfaces (RHIs), which have more degrees of freedom than minimally required to perform a task. ******SPECIFIC AIMS:******* SA 1: Achieve as many of the desirable HI characteristics as possible using appropriately designed RHIs for more intuitive and effective user/RHI interaction. We will investigate the intrinsic advantages of RHIs, which can be obtained through mechanical design, e.g., a lower inertia and a larger workspace (compared to non-redundant HIs).******* SA 2: Leverage the kinematic redundancy of RHIs toward a secondary objective to optimize its kinematic and dynamic characteristics further. Secondary objectives will target further manipulability enhancement, apparent inertia minimization and force feedback capability maximization. Such advantages obtained via joint-level closed-loop control are over and above the intrinsic advantages obtained in SA 1.******* SA 3: Supplement the design in SA 1 and the control in SA 2 with RHI redundancy resolution and impedance modulation based on the requirements of a given task/user. Task- and user-dependent Cartesian-level variable-impedance control and joint-level redundancy resolution of RHIs will further improve the haptic interaction fidelity and the user's task performance.******NOVELTY:******While there is ample research on redundant manipulators that interact with task environments, little attention has been paid to the design and control of RHIs. This research helps create haptic interaction and teleoperation systems with enhanced safety and performance.