Networking Humans, Robots and Environments

Networked Robotics has come a significant way since its inception in the early 90’s in the form of online (web-based) robot systems. Its progress since that time has been allied closely to the development of the web, the Internet and computer networking technology, notably wireless networks. Where is networked robotics now and what does the future hold? This chapter explores these questions from the viewpoint of research in the Active Robotics Laboratory at the University of Reading in the UK for the period from the early 1990s up to 2011. This research has focused on networked robotics as a distributed set of computing and robotics resources. Previous work on online robot systems, distributed software models and cooperative robotics is reviewed along with recent work on swarm systems and swarm-array computing, which takes some of the ideas of networked robotics into the field of fault tolerance for high performance computing systems.

We report an autonomous surveillance system with multiple networked pantilt- zoom (PTZ) cameras assisted by a fixed wide-angle camera. The wide-angle camera provides large but low resolution coverage and detects and tracks all moving objects in the scene. Based on the output of the wide-angle camera, the system generates spatiotemporal observation requests for each moving object, which are candidates for close-up views using PTZ cameras. Due to the fact that there are usually much more objects than the number of PTZ cameras, the system first assigns a subset of the requests/objects to each PTZ camera. The PTZ cameras then select the parameter settings that best satisfy the assigned competing requests to provide high resolution views of the moving objects. We propose an approximation algorithm to solve the request assignment and the camera parameter selection problems in real time. The effectiveness of the proposed system is validated in comparison with an existing work using simulation. The simulation results show that in heavy traffic scenarios, our algorithm increases the number of observed objects by over 210%.

This Chapter introduces a formal language used to model complex relationships between detectable human activities, events and robot behaviours that are to be detected by robots in streams of sensory data. The Ubiquitous Robotics paradigm is adopted in order to show how distributed sources of information can be easily integrated to assess the current context. Specific emphasis is devoted to the use of context assessment techniques to enforce the adaptation of robot behaviours to human activity. The model is described both theoretically and with a thorough example.

We address the problem of dispersing a large number of autonomous mobile robots, for building wireless ad hoc sensor networks performing environmental monitoring and control. For this purpose, we propose the adaptive triangular mesh generation algorithm that enables robots to generate triangular meshes of various sizes, adapting to changing environmental conditions. A locally interacting, geometric technique allows each robot to generate a triangular mesh with its two neighbor robots. Specifically, we have assumed that robots are not allowed to have any identifiers, any pre-determined leaders or common coordinate systems, or any explicit communication. Under such minimal conditions, the positions of the robots were shown to converge to the desired distribution. This convergence was mathematically proven and also verified through extensive simulations. Our results indicate that the proposed algorithm can be applied to problems regarding the coverage of an area of interest by a swarm of mobile sensors.

In previous work, we developed a decentralized framework for formation control by mobile robots. Each robot simultaneously estimates the current swarm shape, by local information diffusion in a communication network, while controlling its own motion to drive the swarm to the desired shape. These continuous-time estimation and control laws result in provably correct behavior, but they make unrealistic assumptions for implementation on actual robots.

This paper describes the first experimental implementation of decentralized estimation and control based on information diffusion. We develop the hardware, software, and communication protocols that adapt the theoretical approach to an actual implementation. Experiments demonstrate that the robots successfully estimate the first and second inertial moments of the swarm, using scalable local communication, while simultaneously moving to control these moments.

We introduce the crucial nodes in sensor networks, whose energy consumption affects the network lifetime greatly. Due to the relative high traffic load at the crucial nodes, energy loss occurs when packet collision and/or retransmission. We propose a LMMSE collision separation technique by combining the space diversity provided by antenna array and network diversity provided by the Media Access Control (MAC) layer. In our solution, collided packets, at the collector, are not discarded but combined with network diversity on-demand to separate data packets from different users and improve the network performance. Using analysis and computer simulations, we demonstrate that the space and network diversity combining (SNDC) scheme for cross-layer and MMSE collision resolution is energy efficient.

Latest advances in network sensor technology and state of the art of mobile robotics and artificial intelligence research can be employed to develop autonomous and distributed monitoring systems. We have been developing “Intelligent Space (iSpace),” which is a space with ubiquitous sensors and actuators. Most of intelligent system interacts with human in a passive space, but iSpace, a space that contains human and artificial systems, is an intelligent system itself. Specific tasks, which cannot be achieved by the iSpace, are accomplished by using the artificial systems. For examples, iSpace utilizes computer monitors to provide information to the human, and robots are utilized to provide physical services to the human as physical agents. In this chapter, we summarize the present state of iSpace and describe the future work from the viewpoint of system integration. We introduce our ongoing researches on essential functions of iSpace – “observation,” “recognition” and “actuation.”

In order to cope with many problems of everyday activities which requires robots to accomplish complex yet routine tasks in changing environments, this study focuses on universality and proposes seven principles of universal design with robots. These principles are used to design ubiquitous robotic spaces. Further, in order to manage and to control the ubiquitous robotic spaces with robots, ambient intelligent systems, and everyday objects, we define inherent functions of objects as ubiquitous functions, and propose a ubiquitous function service with service-oriented architecture for the integration and control of physical and virtual objects under a unified framework, which is composed of smart object service, smart logic service, and smart discovery service. In addition, in order to provide flexible robustness to a robot functioning in the everyday domain, a reproducible robust internal-loop compensator structure is proposed, and the structural design of smart logic service based on this structure is illustrated.

This paper is an extension of the authors’ earlier publication proposing ubiquitous robotic space [1]. In the previous work, authors collaborated to propose a novel robotic service framework. The proposed robotic service framework comprises three conceptual spaces: physical, semantic, and virtual space, which we call a ubiquitous robotic space collectively. We implemented a prototype robotic security application in an office environment, which confirmed that the proposed framework is an efficient tool for developing a robotic service employing IT infrastructure, particularly for integrating heterogeneous technologies involved and dealing with inherent complexity found in robotic platforms. The proposed ubiquitous robotic space architecture is further applied to a large scale artificial environment, which is crowded with hundreds of visitors. This experimental trial proves further the usefulness of the proposed architecture since virtually no modification of the original service architecture is required.

This book chapter proposes the recently-developed passive set-position modulation (PSPM) framework as a promising means toward passive, yet, high-performance haptic teleoperation over the Internet with significant varying-delay and data-loss. We first briefly review some representative control techniques in haptics and time-delay teleoperation (i.e. virtual coupling, passivity observer/controller (or PO/PC), scattering/wave, and proportional-derivative (PD) based approaches) to provide better contextuation/justification for the development of PSPM, with a particular emphasis on how to improve performance. We then provide a condensed derivation of the PSPM framework and a summary of key properties of the PSPM framework and the PSPM based Internet haptic teleoperation, along with the complete algorithm of the PSPM and some illustrative experimental results. Some comments on the future research directions are also given.

A bilateral control scheme is introduced to ensure stable teleoperation under a wide variety of environments and operating speeds. System stability is analyzed in terms of the time domain definition of passivity. A previously proposed energy-based method is extended to a 2-port network, and the issues in implementing the “Passivity Observer” and “Passivity Controller” to teleoperation systems are studied. The method is tested with our two-DOF master/slave teleoperation system. Stable teleoperation is achieved under conditions such as hard wall contact (stiffness > 150 kN/m) and hard surface following.