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Chapter 9 — Force Control

Luigi Villani and Joris De Schutter

A fundamental requirement for the success of a manipulation task is the capability to handle the physical contact between a robot and the environment. Pure motion control turns out to be inadequate because the unavoidable modeling errors and uncertainties may cause a rise of the contact force, ultimately leading to an unstable behavior during the interaction, especially in the presence of rigid environments. Force feedback and force control becomes mandatory to achieve a robust and versatile behavior of a robotic system in poorly structured environments as well as safe and dependable operation in the presence of humans. This chapter starts from the analysis of indirect force control strategies, conceived to keep the contact forces limited by ensuring a suitable compliant behavior to the end effector, without requiring an accurate model of the environment. Then the problem of interaction tasks modeling is analyzed, considering both the case of a rigid environment and the case of a compliant environment. For the specification of an interaction task, natural constraints set by the task geometry and artificial constraints set by the control strategy are established, with respect to suitable task frames. This formulation is the essential premise to the synthesis of hybrid force/motion control schemes.

Experiments of spatial impedance control

Author  Fabrizio Caccavale, Ciro Natale, Bruno Siciliano, Luigi Villani

Video ID : 686

The videod results of an experimental study of impedance control schemes for a robot manipulator in contact with the environment are presented. Six-DOF interaction tasks are considered that require the implementation of a spatial impedance described in terms of both its translational and its rotational parts. Two representations of end-effector orientation are adopted, namely, Euler angles and quaternions, and the implications for the choice of different orientation displacements are discussed. The controllers are tested on an industrial robot with open-control architecture in a number of case studies. This work was published in A. Casals, A.T. de Almeida (Eds.): Experimental Robotics V, Lect. Note. Control Inform. Sci. 232 (Springer, Berlin, Heidelberg 1998)

Chapter 40 — Mobility and Manipulation

Oliver Brock, Jaeheung Park and Marc Toussaint

Mobile manipulation requires the integration of methodologies from all aspects of robotics. Instead of tackling each aspect in isolation,mobilemanipulation research exploits their interdependence to solve challenging problems. As a result, novel views of long-standing problems emerge. In this chapter, we present these emerging views in the areas of grasping, control, motion generation, learning, and perception. All of these areas must address the shared challenges of high-dimensionality, uncertainty, and task variability. The section on grasping and manipulation describes a trend towards actively leveraging contact and physical and dynamic interactions between hand, object, and environment. Research in control addresses the challenges of appropriately coupling mobility and manipulation. The field of motion generation increasingly blurs the boundaries between control and planning, leading to task-consistent motion in high-dimensional configuration spaces, even in dynamic and partially unknown environments. A key challenge of learning formobilemanipulation consists of identifying the appropriate priors, and we survey recent learning approaches to perception, grasping, motion, and manipulation. Finally, a discussion of promising methods in perception shows how concepts and methods from navigation and active perception are applied.

Motor-skill learning for robotics

Author  Jan Peters, Jens Kober, Katharina Mülling

Video ID : 667

We propose to divide the generic skill-learning problem into parts that can be well-understood from a robotics point of view. After appropriate learning approaches have been designed for these basic components, they will serve as the ingredients of a general approach to robot-skill learning. This video shows results of our work on learning to control, learning elementary movements, as well as steps towards the learning of complex tasks.

Interactive perception of articulated objects

Author  Roberto Martin-Martin

Video ID : 676

Interactive perception of articulated objects with multilevel, recursive estimation based on task-specific priors.

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.

IREP tagging spikes

Author  Nabil Simaan

Video ID : 246

This video shows telemanipulation of the IREP (insertible robotic effectors platform). The IREP is a system having 21 controllable axes including two 7-DOF dexterous arms, 3-DOF camera head, an insertion stage, and two grippers [1]. Reference: [1] A. Bajo, R. E. Goldman, L. Wang, D. Fowler, N. Simaan: Integration and preliminary evaluation of an insertable robotic effectors platform for single port access surgery, Proc. 2012 IEEE Int. Conf. Robot. Autom. (ICRA), St. Paul (2012), pp. 3381-3387

Chapter 30 — Sonar Sensing

Lindsay Kleeman and Roman Kuc

Sonar or ultrasonic sensing uses the propagation of acoustic energy at higher frequencies than normal hearing to extract information from the environment. This chapter presents the fundamentals and physics of sonar sensing for object localization, landmark measurement and classification in robotics applications. The source of sonar artifacts is explained and how they can be dealt with. Different ultrasonic transducer technologies are outlined with their main characteristics highlighted.

Sonar systems are described that range in sophistication from low-cost threshold-based ranging modules to multitransducer multipulse configurations with associated signal processing requirements capable of accurate range and bearing measurement, interference rejection, motion compensation, and target classification. Continuous-transmission frequency-modulated (CTFM) systems are introduced and their ability to improve target sensitivity in the presence of noise is discussed. Various sonar ring designs that provide rapid surrounding environmental coverage are described in conjunction with mapping results. Finally the chapter ends with a discussion of biomimetic sonar, which draws inspiration from animals such as bats and dolphins.

Sonar-guided chair at Yale

Author  Roman Kuc

Video ID : 295

Four strategically-placed Polaroid vergence sonar pairs on an electric scooter are controlled by a PIC16877 microcontroller interfaced to the joystick and the wheelchair controller. The sonar vergence pair below the foot stand determines if the obstacle is to the left or right. A sonar vergence pair on each side of the chair (at knee level) determines if the chair can pass by an obstacle without collision. A right-side-looking vergence pair maintains the distance and a parallel path to the wall. When sonar detects obstacles, the user joystick commands are overridden to avoid collision with those obstacles. The blindfolded user navigates a cluttered hallway by holding the joystick in a constant forward position.

Chapter 53 — Multiple Mobile Robot Systems

Lynne E. Parker, Daniela Rus and Gaurav S. Sukhatme

Within the context of multiple mobile, and networked robot systems, this chapter explores the current state of the art. After a brief introduction, we first examine architectures for multirobot cooperation, exploring the alternative approaches that have been developed. Next, we explore communications issues and their impact on multirobot teams in Sect. 53.3, followed by a discussion of networked mobile robots in Sect. 53.4. Following this we discuss swarm robot systems in Sect. 53.5 and modular robot systems in Sect. 53.6. While swarm and modular systems typically assume large numbers of homogeneous robots, other types of multirobot systems include heterogeneous robots. We therefore next discuss heterogeneity in cooperative robot teams in Sect. 53.7. Once robot teams allow for individual heterogeneity, issues of task allocation become important; Sect. 53.8 therefore discusses common approaches to task allocation. Section 53.9 discusses the challenges of multirobot learning, and some representative approaches. We outline some of the typical application domains which serve as test beds for multirobot systems research in Sect. 53.10. Finally, we conclude in Sect. 53.11 with some summary remarks and suggestions for further reading.

Multi-robot box pushing

Author  C. Ronald Kube, Hong Zhang

Video ID : 199

Robots are used to locate an object in the environment (a box with lights on it) and push it to the desired position (an area of the environment with a light shining on it). The robots cannot communicate with each other, and the box is weighted so at least two robots have to push the box to move it. Each robot has three levels of control. First, it wanders randomly looking for the box. Second, it travels toward the box until contact is made. Third, it checks to see if the box is facing the desired direction; if so, it pushes the box, and, if not, it relocates to a different side of the box.

Chapter 41 — Active Manipulation for Perception

Anna Petrovskaya and Kaijen Hsiao

This chapter covers perceptual methods in which manipulation is an integral part of perception. These methods face special challenges due to data sparsity and high costs of sensing actions. However, they can also succeed where other perceptual methods fail, for example, in poor-visibility conditions or for learning the physical properties of a scene.

The chapter focuses on specialized methods that have been developed for object localization, inference, planning, recognition, and modeling in activemanipulation approaches.We concludewith a discussion of real-life applications and directions for future research.

Modeling articulated objects using active manipulation

Author  Juergen Strum

Video ID : 78

The video illustrates a mobile, manipulation robot that interacts with various articulated objects, such as a fridge and a dishwasher, in a kitchen environment. During interaction, the robot learns their kinematic properties such as the rotation axis and the configuration space. Knowing the kinematic model of these objects improves the performance of the robot and enables motion planning. Service robots operating in domestic environments are typically faced with a variety of objects they have to deal with to fulfill their tasks. Some of these objects are articulated such as cabinet doors and drawers, or room and garage doors. The ability to deal with such articulated objects is relevant for service robots, as, for example, they need to open doors when navigating between rooms and to open cabinets to pick up objects in fetch-and-carry applications. We developed a complete probabilistic framework that enables robots to learn the kinematic models of articulated objects from observations of their motion. We combine parametric and nonparametric models consistently and utilize the advantages of both methods. As a result of our approach, a robot can robustly operate articulated objects in unstructured environments. All software is available open-source (including documentation and tutorials) on http://www.ros.org/wiki/articulation.

Chapter 39 — Cooperative Manipulation

Fabrizio Caccavale and Masaru Uchiyama

This chapter is devoted to cooperative manipulation of a common object by means of two or more robotic arms. The chapter opens with a historical overview of the research on cooperativemanipulation, ranging from early 1970s to very recent years. Kinematics and dynamics of robotic arms cooperatively manipulating a tightly grasped rigid object are presented in depth. As for the kinematics and statics, the chosen approach is based on the socalled symmetric formulation; fundamentals of dynamics and reduced-order models for closed kinematic chains are discussed as well. A few special topics, such as the definition of geometrically meaningful cooperative task space variables, the problem of load distribution, and the definition of manipulability ellipsoids, are included to give the reader a complete picture ofmodeling and evaluation methodologies for cooperative manipulators. Then, the chapter presents the main strategies for controlling both the motion of the cooperative system and the interaction forces between the manipulators and the grasped object; in detail, fundamentals of hybrid force/position control, proportional–derivative (PD)-type force/position control schemes, feedback linearization techniques, and impedance control approaches are given. In the last section further reading on advanced topics related to control of cooperative robots is suggested; in detail, advanced nonlinear control strategies are briefly discussed (i. e., intelligent control approaches, synchronization control, decentralized control); also, fundamental results on modeling and control of cooperative systems possessing some degree of flexibility are briefly outlined.

Cooperative capturing via flexible manipulators

Author  Masaru Uchiyama

Video ID : 68

This is a video showing cooperative capturing of a spinning object via flexible manipulators. Reference: T. Miyabe, M. Yamano, A. Konno, M. Uchiyama: An approach towards a robust object recovery with flexible manipulators, Proc. IEEE/RSJ Int. Conf. Intel. Robot. Syst. (2001) pp. 907-912.

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.

Semi-autonomous teleoperation of multiple UAVs: Tumbling over an obstacle

Author  Antonio Franchi, Paolo Robuffo Giordano

Video ID : 72

This video shows the bilateral teleoperation of a group of four quadrotor UAVs navigating in a cluttered environment. The human operator provides velocity-level motion commands and receives force-feedback information on the UAV interaction with the environment (e.g., presence of obstacles and external disturbances).

Chapter 63 — Medical Robotics and Computer-Integrated Surgery

Russell H. Taylor, Arianna Menciassi, Gabor Fichtinger, Paolo Fiorini and Paolo Dario

The growth of medical robotics since the mid- 1980s has been striking. From a few initial efforts in stereotactic brain surgery, orthopaedics, endoscopic surgery, microsurgery, and other areas, the field has expanded to include commercially marketed, clinically deployed systems, and a robust and exponentially expanding research community. This chapter will discuss some major themes and illustrate them with examples from current and past research. Further reading providing a more comprehensive review of this rapidly expanding field is suggested in Sect. 63.4.

Medical robotsmay be classified in many ways: by manipulator design (e.g., kinematics, actuation); by level of autonomy (e.g., preprogrammed versus teleoperation versus constrained cooperative control), by targeted anatomy or technique (e.g., cardiac, intravascular, percutaneous, laparoscopic, microsurgical); or intended operating environment (e.g., in-scanner, conventional operating room). In this chapter, we have chosen to focus on the role of medical robots within the context of larger computer-integrated systems including presurgical planning, intraoperative execution, and postoperative assessment and follow-up.

First, we introduce basic concepts of computerintegrated surgery, discuss critical factors affecting the eventual deployment and acceptance of medical robots, and introduce the basic system paradigms of surgical computer-assisted planning, execution, monitoring, and assessment (surgical CAD/CAM) and surgical assistance. In subsequent sections, we provide an overview of the technology ofmedical robot systems and discuss examples of our basic system paradigms, with brief additional discussion topics of remote telesurgery and robotic surgical simulators. We conclude with some thoughts on future research directions and provide suggested further reading.

IREP robot - Insertable robotic effectors in single-port surgery

Author  Columbia University

Video ID : 831

This movie shows the single-port-access surgical robot IREP. This multimedia extension accompanies the IEEE ICRA 2010 paper describing design considerations for suturing. The work was carried out by Jienan Ding, Kai Xu, Roger Goldman, and Nabil Simaan at ARMA lab in collaboration with Peter Allen and Dennis Fowler from Columbia University.