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Chapter 38 — Grasping

Domenico Prattichizzo and Jeffrey C. Trinkle

This chapter introduces fundamental models of grasp analysis. The overall model is a coupling of models that define contact behavior with widely used models of rigid-body kinematics and dynamics. The contact model essentially boils down to the selection of components of contact force and moment that are transmitted through each contact. Mathematical properties of the complete model naturally give rise to five primary grasp types whose physical interpretations provide insight for grasp and manipulation planning.

After introducing the basic models and types of grasps, this chapter focuses on the most important grasp characteristic: complete restraint. A grasp with complete restraint prevents loss of contact and thus is very secure. Two primary restraint properties are form closure and force closure. A form closure grasp guarantees maintenance of contact as long as the links of the hand and the object are well-approximated as rigid and as long as the joint actuators are sufficiently strong. As will be seen, the primary difference between form closure and force closure grasps is the latter’s reliance on contact friction. This translates into requiring fewer contacts to achieve force closure than form closure.

The goal of this chapter is to give a thorough understanding of the all-important grasp properties of form and force closure. This will be done through detailed derivations of grasp models and discussions of illustrative examples. For an indepth historical perspective and a treasure-trove bibliography of papers addressing a wide range of topics in grasping, the reader is referred to [38.1].

Grasp analysis using the MATLAB toolbox SynGrasp

Author  Monica Malvezzi, Guido Gioioso, Gionata Salvietti, Domenico Prattichizzo

Video ID : 551

In this video a examples of few grasp analysis are documented and reported. The analysis is performed using SynGrasp, a MATLAB toolbox for grasp analysis. It provides a graphical user interface (GUI) which the user can adopt to easily load a hand and an object, and a series of functions that the user can assemble and modify to exploit all the toolbox features. The video shows how to use SynGrasp to model and analyze grasping, and, in particular it shows how users can select and load in the GUI a hand model, then choose an object and place it in the workspace selecting its position w.r.t. the hand. The grasp is obtained closing the hand from an initial configuration, which can be set by the users acting on hand joints. Once the grasp is defined, it can be analyzed by evaluating grasp quality measures available in the toolbox. Grasps can be described either using the provided grasp planner or directly defining contact points on the hand with the respective contact normal directions. SynGrasp can model both fully and underactuated robotic hands. An important role in grasp analysis, in particular with underactuated hands, is played by system compliance. SynGrasp can model the stiffness at contact points, at the joints or in the actuation system including transmission. A wide set of analytical functions, continuously increasing with new features and capabilities, has been developed to investigate the main grasp properties: controllable forces and object displacement, manipulability analysis, grasp stiffness and different measures of grasp quality. A set of functions for the graphical representation of the hand, the object, and the main analysis results is provided. The toolbox is freely available at http://syngrasp.dii.unisi.it.

Chapter 21 — Actuators for Soft Robotics

Alin Albu-Schäffer and Antonio Bicchi

Although we do not know as yet how robots of the future will look like exactly, most of us are sure that they will not resemble the heavy, bulky, rigid machines dangerously moving around in old fashioned industrial automation. There is a growing consensus, in the research community as well as in expectations from the public, that robots of the next generation will be physically compliant and adaptable machines, closely interacting with humans and moving safely, smoothly and efficiently - in other terms, robots will be soft.

This chapter discusses the design, modeling and control of actuators for the new generation of soft robots, which can replace conventional actuators in applications where rigidity is not the first and foremost concern in performance. The chapter focuses on the technology, modeling, and control of lumped parameters of soft robotics, that is, systems of discrete, interconnected, and compliant elements. Distributed parameters, snakelike and continuum soft robotics, are presented in Chap. 20, while Chap. 23 discusses in detail the biomimetic motivations that are often behind soft robotics.

Safety evaluation of lightweight robots

Author  Sami Haddadin

Video ID : 463

Inteview with Sami Haddadin on safety evaluation of lightweight robots (Discovery Channel interview "Daily Planet", January 9th, 2008)

Chapter 23 — Biomimetic Robots

Kyu-Jin Cho and Robert Wood

Biomimetic robot designs attempt to translate biological principles into engineered systems, replacing more classical engineering solutions in order to achieve a function observed in the natural system. This chapter will focus on mechanism design for bio-inspired robots that replicate key principles from nature with novel engineering solutions. The challenges of biomimetic design include developing a deep understanding of the relevant natural system and translating this understanding into engineering design rules. This often entails the development of novel fabrication and actuation to realize the biomimetic design.

This chapter consists of four sections. In Sect. 23.1, we will define what biomimetic design entails, and contrast biomimetic robots with bio-inspired robots. In Sect. 23.2, we will discuss the fundamental components for developing a biomimetic robot. In Sect. 23.3, we will review detailed biomimetic designs that have been developed for canonical robot locomotion behaviors including flapping-wing flight, jumping, crawling, wall climbing, and swimming. In Sect. 23.4, we will discuss the enabling technologies for these biomimetic designs including material and fabrication.

RHex the parkour robot

Author  Uluc Saranli, Martin Buehler, Daniel E. Koditschek

Video ID : 400

RHex is an all-terrain walking robot that could conceivably one day climb over rubble in a rescue mission or cross the desert with environmental sensors strapped to its back. The name is pronounced "Rex" like the over-excited puppy it resembles when it is bounding over the ground; RHex is short for "robot hexapod", a name that stems from its six springy legs.

Chapter 10 — Redundant Robots

Stefano Chiaverini, Giuseppe Oriolo and Anthony A. Maciejewski

This chapter focuses on redundancy resolution schemes, i. e., the techniques for exploiting the redundant degrees of freedom in the solution of the inverse kinematics problem. This is obviously an issue of major relevance for motion planning and control purposes.

In particular, task-oriented kinematics and the basic methods for its inversion at the velocity (first-order differential) level are first recalled, with a discussion of the main techniques for handling kinematic singularities. Next, different firstorder methods to solve kinematic redundancy are arranged in two main categories, namely those based on the optimization of suitable performance criteria and those relying on the augmentation of the task space. Redundancy resolution methods at the acceleration (second-order differential) level are then considered in order to take into account dynamics issues, e.g., torque minimization. Conditions under which a cyclic task motion results in a cyclic joint motion are also discussed; this is a major issue when a redundant manipulator is used to execute a repetitive task, e.g., in industrial applications. The use of kinematic redundancy for fault tolerance is analyzed in detail. Suggestions for further reading are given in a final section.

KUKA LBR iiwa - Kinematic Redundancy

Author  KUKA Roboter GmbH

Video ID : 813

The video shows the robot dexterity achieved by kinematic redundancy and illustrates the basic concept of self-motion (here called null-space motion).

Chapter 55 — Space Robotics

Kazuya Yoshida, Brian Wilcox, Gerd Hirzinger and Roberto Lampariello

In the space community, any unmanned spacecraft can be called a robotic spacecraft. However, Space Robots are considered to be more capable devices that can facilitate manipulation, assembling, or servicing functions in orbit as assistants to astronauts, or to extend the areas and abilities of exploration on remote planets as surrogates for human explorers.

In this chapter, a concise digest of the historical overview and technical advances of two distinct types of space robotic systems, orbital robots and surface robots, is provided. In particular, Sect. 55.1 describes orbital robots, and Sect. 55.2 describes surface robots. In Sect. 55.3, the mathematical modeling of the dynamics and control using reference equations are discussed. Finally, advanced topics for future space exploration missions are addressed in Sect. 55.4.

DLR ROKVISS animation

Author  Gerd Hirzinger, Klaus Landzettel

Video ID : 333

ROKVISS: animated simulation of a two-joint, torque- controlled manipulator on the ISS as it performs an iInspection task. The split screen shows simulated views of the robot (at top) and the stereo camera's view of the robot end-effector (at bottom).

Chapter 12 — Robotic Systems Architectures and Programming

David Kortenkamp, Reid Simmons and Davide Brugali

Robot software systems tend to be complex. This complexity is due, in large part, to the need to control diverse sensors and actuators in real time, in the face of significant uncertainty and noise. Robot systems must work to achieve tasks while monitoring for, and reacting to, unexpected situations. Doing all this concurrently and asynchronously adds immensely to system complexity.

The use of a well-conceived architecture, together with programming tools that support the architecture, can often help to manage that complexity. Currently, there is no single architecture that is best for all applications – different architectures have different advantages and disadvantages. It is important to understand those strengths and weaknesses when choosing an architectural approach for a given application.

This chapter presents various approaches to architecting robotic systems. It starts by defining terms and setting the context, including a recounting of the historical developments in the area of robot architectures. The chapter then discusses in more depth the major types of architectural components in use today – behavioral control (Chap. 13), executives, and task planners (Chap. 14) – along with commonly used techniques for interconnecting connecting those components. Throughout, emphasis will be placed on programming tools and environments that support these architectures. A case study is then presented, followed by a brief discussion of further reading.

Software product line engineering for robotics

Author  Davide Brugali

Video ID : 273

The video illustrates the software product-line approach to the development of robot software control systems and the open source HyperFlex toolchain that supports it.

Chapter 19 — Robot Hands

Claudio Melchiorri and Makoto Kaneko

Multifingered robot hands have a potential capability for achieving dexterous manipulation of objects by using rolling and sliding motions. This chapter addresses design, actuation, sensing and control of multifingered robot hands. From the design viewpoint, they have a strong constraint in actuator implementation due to the space limitation in each joint. After briefly introducing the overview of anthropomorphic end-effector and its dexterity in Sect. 19.1, various approaches for actuation are provided with their advantages and disadvantages in Sect. 19.2. The key classification is (1) remote actuation or build-in actuation and (2) the relationship between the number of joints and the number of actuator. In Sect. 19.3, actuators and sensors used for multifingered hands are described. In Sect. 19.4, modeling and control are introduced by considering both dynamic effects and friction. Applications and trends are given in Sect. 19.5. Finally, this chapter is closed with conclusions and further reading.

The Barrett Hand

Author  Barrett Technology Inc.

Video ID : 752

The Barrett Hand is one of the first effective commercial robot grippers. Although it is not an anthropomorphic hand, its kinematics and actuation system enable a great diversity of grasps.

Chapter 34 — Visual Servoing

François Chaumette, Seth Hutchinson and Peter Corke

This chapter introduces visual servo control, using computer vision data in the servo loop to control the motion of a robot. We first describe the basic techniques that are by now well established in the field. We give a general overview of the formulation of the visual servo control problem, and describe the two archetypal visual servo control schemes: image-based and pose-based visual servo control. We then discuss performance and stability issues that pertain to these two schemes, motivating advanced techniques. Of the many advanced techniques that have been developed, we discuss 2.5-D, hybrid, partitioned, and switched approaches. Having covered a variety of control schemes, we deal with target tracking and controlling motion directly in the joint space and extensions to under-actuated ground and aerial robots. We conclude by describing applications of visual servoing in robotics.

PBVS on a 6-DOF robot arm (2)

Author  Francois Chaumette, Seth Hutchinson, Peter Corke

Video ID : 63

This video shows a PBVS on a 6-DOF robot arm with (c*^t_c, theta u) as visual features. It corresponds to the results depicted in Figure 34.10.

Chapter 23 — Biomimetic Robots

Kyu-Jin Cho and Robert Wood

Biomimetic robot designs attempt to translate biological principles into engineered systems, replacing more classical engineering solutions in order to achieve a function observed in the natural system. This chapter will focus on mechanism design for bio-inspired robots that replicate key principles from nature with novel engineering solutions. The challenges of biomimetic design include developing a deep understanding of the relevant natural system and translating this understanding into engineering design rules. This often entails the development of novel fabrication and actuation to realize the biomimetic design.

This chapter consists of four sections. In Sect. 23.1, we will define what biomimetic design entails, and contrast biomimetic robots with bio-inspired robots. In Sect. 23.2, we will discuss the fundamental components for developing a biomimetic robot. In Sect. 23.3, we will review detailed biomimetic designs that have been developed for canonical robot locomotion behaviors including flapping-wing flight, jumping, crawling, wall climbing, and swimming. In Sect. 23.4, we will discuss the enabling technologies for these biomimetic designs including material and fabrication.

Torque-control strategies for snake robots

Author  David Rollinson, Kalyan Vasudev Alwala, Nico Zevallos, Howie Choset

Video ID : 392

This video provides an overview of some initial torque-based motions for the series elastic snake robot (SEA Snake). Because the SEA Snake has the unique ability to accurately sense and control the torque of each of its joints, it can execute life-like compliant and adaptive motions, without a complex controller or tactile sensing.

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 autonomous pole-climbing

Author  Howie Choset

Video ID : 166

Video of the CMU Modsnake autonomously climbing a pole using LIDAR.