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Über dieses Buch

This book introduces novel thinking and techniques to the control of robotic manipulation. In particular, the concept of teleimpedance control as an alternative method to bilateral force-reflecting teleoperation control for robotic manipulation is introduced. In teleimpedance control, a compound reference command is sent to the slave robot including both the desired motion trajectory and impedance profile, which are then realized by the remote controller. This concept forms a basis for the development of the controllers for a robotic arm, a dual-arm setup, a synergy-driven robotic hand, and a compliant exoskeleton for improved interaction performance.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
Over the past decades, applications of robots in unstructured and hostile for human environments have seen an intensive use of Master-Slave teleoperation systems often based on feedback sensory data. In these systems, a human operator executes a task by controlling a manipulator (Slave) located in the remote environment using a robotic interface (Master) located at the human site. The execution of the remotely performed task is usually assisted by feeding back to the master and human operator kinesthetic feedback conveying information about the force interaction between the slave robot and the remote environment.
Arash Ajoudani

Chapter 2. On the Role of Compliance and Geometry in Mechanical Stability of the Humans and Robots

Abstract
Humans demonstrate versatile and stable interactions with the uncertain environment. This is achieved through the modulation of the mechanical properties of the limb, and as a consequence, task-related restoring forces are applied in response to the environmental displacements.
Arash Ajoudani

Teleimpedance Control of a Robotic Arm

Frontmatter

Chapter 3. Teleimpedance: Teleoperation with Impedance Regulation Using a Body-Machine Interface

Abstract
Master-Slave teleoperation systems for unstructured and hostile environments have been studied and applied for a long time, starting even before the emergence of robotics systems [101]. Earlier prototypes using position measurements from the human operator arm to be replicated by a rigid manipulator soon showed their limitations in dealing with interaction tasks in uncertain environments, due to high forces developing at contacts. The second generation of teleoperation systems therefore included means of feeding back to the operator information on the interaction forces between the slave robot and the remote environment. Although such bilateral teleoperation systems can outperform pure position—controlled ones, they require an active force display on the master side (e.g., an actuated exoskeleton), which imposes extra costs and discomfort for the operator. Furthermore, latencies in the communication channel between the master and slave robot may generate insufficient transparency or even stability issues in the bilateral teleoperation system (see e.g. [38, 102, 103]).
Arash Ajoudani

Chapter 4. Replicating Human Stiffness Profile with a Cartesian Impedance Controller in Realtime

Abstract
In this chapter, we evaluate the efficiency of the teleimpedance algorithm in two experimental tasks, illustrating different and complementary aspects of the method. The first concerns a classic peg-in-hole task, and is used to illustrate the stability, transparency, and safety characteristics of the method. The second experiment, a ball-reception task, is chosen to assess how effective is the incorporation of human impedance regulation skills in performing tasks with significant dynamics. In both experiments, the slave robot performs the task by tracking both the reference position profile (which corresponds to the endpoint position of the arm of the human operator as measured from an optical position tracking system) and the end-point stiffness profile (estimated from the muscular activities of the operator’s arm) in real-time, via a Cartesian impedance controller. Eventually, the performance of the proposed algorithm is compared to the behavior of the robot arm with different constant stiffness settings.
Arash Ajoudani

Chapter 5. Exploring the Roles of Common Mode Stiffness (CMS) and Configuration Dependent Stiffness (CDS) Control

Abstract
As mentioned in the introduction of this book, humans demonstrate versatile and stable interactions with uncertain environments. Such stability is guaranteed by generating efficient and task-related restoring forces in response to environmental displacements [51], and is accomplished by co-activation of the muscles acting on the joints.
Arash Ajoudani

Human-like Impedance Control of a Dual-Arm Manipulator

Frontmatter

Chapter 6. Natural Redundancy Resolution in Dual-Arm Manipulation Using CDS Control

Abstract
In recent years the fast growing interest in versatility and flexibility of robotic systems working closely and interacting with humans in co-operative tasks or acting as assisting or prosthesis systems had led to the development of a wide range of systems: from full body humanoid robot co-workers to anthropomorphic manipulator prosthesis and exoskeleton systems aiming to aid and improve the life of humans with special needs.
Arash Ajoudani

Teleimpedance Control of a Robotic Hand

Frontmatter

Chapter 7. A Synergy-Driven Approach to a Myoelectric Hand

Abstract
The primary causes of amputation are trauma, disease, and war, the proportions of which are skewed towards the former two in developed countries and the latter in the developing world. It is estimated that one in 200 people in the United States have a missing limb [148], although global numbers are difficult to estimate [149]. Following amputation, an individual must overcome significant physical and functional loss as well as the psychological trauma of change in independence and appearance. Prostheses have emerged to help cope with these immense changes. Body-powered prostheses were created to restore function and have seen great advancements in the last century. These prostheses provide several benefits including functionality, robustness, and limited sensory feedback. The next generation of prostheses has seen the incorporation of electronic components controlled via electromyographic (EMG) signals from the muscles in the residual limb. These myoelectric prostheses can provide greater control of the hand and a more aesthetically pleasing appearance.
Arash Ajoudani

Chapter 8. Exploring Teleimpedance and Tactile Feedback for Intuitive Control of the Pisa/IIT SoftHand

Abstract
To further exploit the efficiency and robustness of a synergy-driven robotic hand, we present a novel myoelectric impedance controller. This chapter extends the impedance control scheme and hand synergy reference models, previously presented in Chap. 7, and presents a novel teleimpedance controller for the Pisa/IIT SoftHand. In addition, different haptic interfaces are developed to provide the user with some information about the grasping forces and texture.
Arash Ajoudani

Teleimpedance Control of a Compliant Knee Exoskeleton

Frontmatter

Chapter 9. Teleimpedance Based Assistive Control for a Compliant Knee Exoskeleton

Abstract
Assistive exoskeletons have undergone continuous technological development over the last few years. Depending on the application, such devices can augment the muscular force of healthy individuals Zoss et al., Trans IEEE/ASME Mech, 11(2):128–138, 2006 [213], provide motion assistance to the elderly or to those with limited physical capability Kong and Jeon, Trans IEEE/ASME Mech, 11(4):428–432, 2006 [214] and be used for rehabilitational purposes for patients with impaired mobility function Veneman et al., IEEE Trans Neural Syst Rehabil Eng, 15(3):379–386, 2007 [215] and Riener et al., IEEE Trans Neural Syst Rehabil Eng, 13(3):380–394, 2005 [216].
Arash Ajoudani

Chapter 10. Human-Inspired Balancing Assistance: Application to a Knee Exoskeleton

Abstract
During every day life, unexpected external disturbances are a common event. Especially for elderly people and individuals with mobility disorders maintaining balance is a challenging task. Several biomechanical and physiological studies have been conducted to investigate strategies of human balancing during quiet standing and also during disturbances (Winter, 3(4), 193–214, 1995 [243], Loram, Lakie, 543(3), 1111–1124, 2002 [244], Crenna, Frigo, 437(1), 635–653, 1991 [245]). However, many questions concerning the mechanisms of the human’s biomechanical system strategy still remain unanswered.
Arash Ajoudani

Chapter 11. Conclusions

Abstract
In this book the concept of teleimpedance control was introduced, as a method to effectively transfer the task-oriented stiffness profile from the human master to the robotic slave device. As an alternative to position-based or closed-loop bilateral force-reflecting teleoperation, the proposed approach enriches the command sent to the slave robot by combining the position reference with a stiffness (or full impedance) reference estimated from the human operator. The stiffness command to the robot was derived in real time from the measurement of EMGs from corresponding muscles of the operator.
Arash Ajoudani

Backmatter

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