Advantages of reconfigurable and variable-impedance haptic user interfaces

背景：触觉交互是人类理解环境并影响环境变化的最基本方式。触觉反馈为操作机器(例如，飞机、挖掘机或机器人，如Canadarm或火星漫游者)的人提供了触摸他们实际上没有触摸但正在由机器操纵的对象的感觉。触觉反馈使机器的人类操作员能够更温和、安全、可靠和准确地处理对象。*触觉界面(HIS)通过向用户的手施加力来产生触摸的错觉。HI应该有一个很大的工作空间。它还应满足后驱动、低表观惯量和低摩擦的要求，以获得对小反射力的最佳感知，以及大的固有刚度和力反馈能力，以获得对大反射力的最佳感知。然后，HI可以为用户重现高保真的柔软和僵硬的接触体验。*目标：*现有的HIS要么是力反馈能力较高、固有刚度较高、工作空间较小的并联机构，要么是力反馈能力较低、固有刚度较低、工作空间较大的串联机构。由于高的力反馈能力、高的固有刚度和大的工作空间是理想的，本研究将通过对冗余触觉接口(RHIS)进行适当的设计和控制(包括可变阻抗控制)来确保两全其美，冗余触觉接口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实现尽可能多的所需HI特征，以实现更直观、更有效的用户/RHI交互。我们将研究RHIS的内在优势，这可以通过机械设计获得，例如，更低的惯量和更大的工作空间(与非冗余HIS相比)。*SA2：利用RHIS的运动学冗余来进一步优化其运动学和动力学特性。次要目标将以进一步增强操纵性、表观惯性最小化和力反馈能力最大化为目标。通过联合级闭环控制获得的这种优势超过了SA 1获得的固有优势。*SA 3：根据给定任务/用户的要求，在SA 1和SA 2中的设计基础上补充RHI冗余分辨率和阻抗调制。RHIS的基于任务和用户的笛卡尔变阻抗控制和关节级冗余度分解将进一步提高触觉交互的逼真度和用户的任务性能。*新颖性：*虽然关于与任务环境交互的冗余度机械手的研究很多，但对RHIS的设计和控制关注较少。这项研究有助于创建具有增强的安全性和性能的触觉交互和遥操作系统。

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.