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Chapter 20 — Snake-Like and Continuum Robots

Ian D. Walker, Howie Choset and Gregory S. Chirikjian

This chapter provides an overview of the state of the art of snake-like (backbones comprised of many small links) and continuum (continuous backbone) robots. The history of each of these classes of robot is reviewed, focusing on key hardware developments. A review of the existing theory and algorithms for kinematics for both types of robot is presented, followed by a summary ofmodeling of locomotion for snake-like and continuum mechanisms.

Modsnake fence navigation

Author  Howie Choset

Video ID : 165

Video of the CMU Modsnake navigating under a fence.

Chapter 43 — Telerobotics

Günter Niemeyer, Carsten Preusche, Stefano Stramigioli and Dongjun Lee

In this chapter we present an overview of the field of telerobotics with a focus on control aspects. To acknowledge some of the earliest contributions and motivations the field has provided to robotics in general, we begin with a brief historical perspective and discuss some of the challenging applications. Then, after introducing and classifying the various system architectures and control strategies, we emphasize bilateral control and force feedback. This particular area has seen intense research work in the pursuit of telepresence. We also examine some of the emerging efforts, extending telerobotic concepts to unconventional systems and applications. Finally,we suggest some further reading for a closer engagement with the field.

Passivity of IPC strategy at 30-Hz sample rate

Author  Stefano Stramigioli

Video ID : 724

In this short video, the effectiveness of the passive sampling approach and IPC control are shown. A "PD" like control is implemented digitally in the classical way and also using IPC and passive sampling. At the used sampling frequency of 30 Hz, it is shown that instability occurs for the standard implementation, but is completely absent in the proposed way.

Chapter 76 — Evolutionary Robotics

Stefano Nolfi, Josh Bongard, Phil Husbands and Dario Floreano

Evolutionary Robotics is a method for automatically generating artificial brains and morphologies of autonomous robots. This approach is useful both for investigating the design space of robotic applications and for testing scientific hypotheses of biological mechanisms and processes. In this chapter we provide an overview of methods and results of Evolutionary Robotics with robots of different shapes, dimensions, and operation features. We consider both simulated and physical robots with special consideration to the transfer between the two worlds.

Evolved homing walk on rough ground

Author  Phil Husbands

Video ID : 373

Evolved, simulated hexapod walks over rough terrain while homing on a beacon. This behavior was incrementally evolved with the controlling neural-network architecture which was expanding at each stage. Work done at Sussex University by Eric Vaughan.

Chapter 11 — Robots with Flexible Elements

Alessandro De Luca and Wayne J. Book

Design issues, dynamic modeling, trajectory planning, and feedback control problems are presented for robot manipulators having components with mechanical flexibility, either concentrated at the joints or distributed along the links. The chapter is divided accordingly into two main parts. Similarities or differences between the two types of flexibility are pointed out wherever appropriate.

For robots with flexible joints, the dynamic model is derived in detail by following a Lagrangian approach and possible simplified versions are discussed. The problem of computing the nominal torques that produce a desired robot motion is then solved. Regulation and trajectory tracking tasks are addressed by means of linear and nonlinear feedback control designs.

For robots with flexible links, relevant factors that lead to the consideration of distributed flexibility are analyzed. Dynamic models are presented, based on the treatment of flexibility through lumped elements, transfer matrices, or assumed modes. Several specific issues are then highlighted, including the selection of sensors, the model order used for control design, and the generation of effective commands that reduce or eliminate residual vibrations in rest-to-rest maneuvers. Feedback control alternatives are finally discussed.

In each of the two parts of this chapter, a section is devoted to the illustration of the original references and to further readings on the subject.

Trajectory generation and control for a KUKA IR 161/60 robot

Author  Joris De Schutter

Video ID : 770

This ICRA 1992 video shows the performance obtained with two simple modifications of a standard robot controller for a KUKA IR 161/60 industrial robot, namely improved trajectory generation and control of the first joint bases on a flexible joint model. At very high velocities and accelerations, there is a significant difference between the flexible controller and a classical PID controller. A nonlinear flexible controller implemented for links 2 and 3 improves the static and dynamic accuracy of the robot. Reference: J. Swevers, D. Torfs, M. Adams, J. De Schutter, H. Van Brussel: Comparison of control algorithms for flexible joint robots implemented on a Kuka IR 161/60 industrial robot, 5th Int. Conf. Adv. Robot., Pisa (1991), pp. 120-125; doi: 10.1109/ICAR.1991.240465

Chapter 56 — Robotics in Agriculture and Forestry

Marcel Bergerman, John Billingsley, John Reid and Eldert van Henten

Robotics for agriculture and forestry (A&F) represents the ultimate application of one of our society’s latest and most advanced innovations to its most ancient and important industries. Over the course of history, mechanization and automation increased crop output several orders of magnitude, enabling a geometric growth in population and an increase in quality of life across the globe. Rapid population growth and rising incomes in developing countries, however, require ever larger amounts of A&F output. This chapter addresses robotics for A&F in the form of case studies where robotics is being successfully applied to solve well-identified problems. With respect to plant crops, the focus is on the in-field or in-farm tasks necessary to guarantee a quality crop and, generally speaking, end at harvest time. In the livestock domain, the focus is on breeding and nurturing, exploiting, harvesting, and slaughtering and processing. The chapter is organized in four main sections. The first one explains the scope, in particular, what aspects of robotics for A&F are dealt with in the chapter. The second one discusses the challenges and opportunities associated with the application of robotics to A&F. The third section is the core of the chapter, presenting twenty case studies that showcase (mostly) mature applications of robotics in various agricultural and forestry domains. The case studies are not meant to be comprehensive but instead to give the reader a general overview of how robotics has been applied to A&F in the last 10 years. The fourth section concludes the chapter with a discussion on specific improvements to current technology and paths to commercialization.

Ladybird: An intelligent farm robot for the vegetable industry

Author  James Underwood, Calvin Hung, Suchet Bargoti, Mark Calleija, Robert Fitch, Juan Nieto, Salah Sukkarieh

Video ID : 305

This video showcases the Ladybird, an intelligent robot for the vegetable industry. Ladybird provides a flexible platform for sensing and automating commercial vegetable farms. The solar-electric powered vehicle has a flexible drive system that allows precise motion in potentially tight environments, and the platform geometry can be configured to suit different crop configurations. The vehicle autonomously traverses the farm, gathering data from a variety of sensors, including stereo vision, hyperspectral, thermal, and LIDAR. The data is processed to provide useful information for the management and optimization of the crop, including yield mapping, phenotyping, and disease and stress detection. Ladybird is equipped with a manipulator arm for a variety of mechanical tasks, including thinning, weeding (especially of herbicide-resistant weeds), spot spraying, foreign body removal and to support research towards automated harvesting.

Chapter 52 — Modeling and Control of Aerial Robots

Robert Mahony, Randal W. Beard and Vijay Kumar

Aerial robotic vehicles are becoming a core field in mobile robotics. This chapter considers some of the fundamental modelling and control architectures in the most common aerial robotic platforms; small-scale rotor vehicles such as the quadrotor, hexacopter, or helicopter, and fixed wing vehicles. In order to control such vehicles one must begin with a good but sufficiently simple dynamic model. Based on such models, physically motivated control architectures can be developed. Such algorithms require realisable target trajectories along with real-time estimates of the system state obtained from on-board sensor suite. This chapter provides a first introduction across all these subjects for the quadrotor and fixed wing aerial robotic vehicles.

Autopilot using total-energy control

Author  Randy Beard

Video ID : 436

This video shows simulation results of an autopilot wich controls the lateral modes using a standard nested loop structure; the longitudinal autopilot is designed using the total-energy control structure. The commands to the autopilot are for airspeed, course angle, and altitude. The video shows a number of different step commands in these variables and the performance of a six-DOF aerodynamic model of a Zagi-style fixed-wing aircraft.

Chapter 69 — Physical Human-Robot Interaction

Sami Haddadin and Elizabeth Croft

Over the last two decades, the foundations for physical human–robot interaction (pHRI) have evolved from successful developments in mechatronics, control, and planning, leading toward safer lightweight robot designs and interaction control schemes that advance beyond the current capacities of existing high-payload and highprecision position-controlled industrial robots. Based on their ability to sense physical interaction, render compliant behavior along the robot structure, plan motions that respect human preferences, and generate interaction plans for collaboration and coaction with humans, these novel robots have opened up novel and unforeseen application domains, and have advanced the field of human safety in robotics.

This chapter gives an overview on the state of the art in pHRI as of the date of publication. First, the advances in human safety are outlined, addressing topics in human injury analysis in robotics and safety standards for pHRI. Then, the foundations of human-friendly robot design, including the development of lightweight and intrinsically flexible force/torque-controlled machines together with the required perception abilities for interaction are introduced. Subsequently, motionplanning techniques for human environments, including the domains of biomechanically safe, risk-metric-based, human-aware planning are covered. Finally, the rather recent problem of interaction planning is summarized, including the issues of collaborative action planning, the definition of the interaction planning problem, and an introduction to robot reflexes and reactive control architecture for pHRI.

Justin: A humanoid upper body system for two-handed manipulation experiments

Author  Christoph Borst, Christian Ott, Thomas Wimböck, Bernhard Brunner, Franziska Zacharias, Berthold Bäuml

Video ID : 626

This video presents a humanoid two-arm system developed as a research platform for studying dexterous two-handed manipulation. The system is based on the modular DLR-Lightweight-Robot-III and the DLR-Hand-II. Two arms and hands are combined with a 3-DOF movable torso and a visual system to form a complete humanoid upper body. The diversity of the system is demonstrated by showing the mechanical design, several control concepts, the application of rapid prototyping and hardware-in-the-loop (HIL) development, as well as two-handed manipulation experiments and the integration of path planning capabilities.

Chapter 70 — Human-Robot Augmentation

Massimo Bergamasco and Hugh Herr

The development of robotic systems capable of sharing with humans the load of heavy tasks has been one of the primary objectives in robotics research. At present, in order to fulfil such an objective, a strong interest in the robotics community is collected by the so-called wearable robots, a class of robotics systems that are worn and directly controlled by the human operator. Wearable robots, together with powered orthoses that exploit robotic components and control strategies, can represent an immediate resource also for allowing humans to restore manipulation and/or walking functionalities.

The present chapter deals with wearable robotics systems capable of providing different levels of functional and/or operational augmentation to the human beings for specific functions or tasks. Prostheses, powered orthoses, and exoskeletons are described for upper limb, lower limb, and whole body structures. State-of-theart devices together with their functionalities and main components are presented for each class of wearable system. Critical design issues and open research aspects are reported.

Arm-Exos

Author  Massimo Bergamasco

Video ID : 148

The video details the Arm-Exos and, in particular, its capability for tracking the operator's motions and for rendering the contact forces in a simple, demonstrative, virtual environment.