https://www.science.smith.edu/~jcardell/Courses/EGR328/Readings/WSNSurvey2.pdf

Wireless sensor network survey

Wireless sensor network (WSN) has emerged as one of the most promising technologies for the future. This has been enabled by advances in technology and availability of small, inexpensive, and smart sensors resulting in cost effective and easily deployable WSNs. However, researchers must address a variety of challenges to facilitate the widespread deployment of WSN technology in real-world domains. In this survey, we give an overview of wireless sensor networks and their application domains including the challenges that should be addressed in order to push the technology further. Then we review the recent technologies and testbeds for WSNs. Finally, we identify several open research issues that need to be investigated in future.

Our survey is different from existing surveys in that we focus on recent developments in wireless sensor network technologies. We review the leading research projects, standards and technologies, and platforms. Moreover, we highlight a recent phenomenon in WSN research that is to explore synergy between sensor networks and other technologies and explain how this can help sensor networks achieve their full potential. This paper intends to help new researchers entering the domain of WSNs by providing a comprehensive survey on recent developments.

Wireless sensor networks: a survey on recent developments and potential synergies

Open Dynamics Engine を用いたスノーボードロボットシミュレータの開発

The availability of low-cost hardware is enabling the development of wireless multimedia sensor networks (WMSNs), i.e., networks of resource-constrained wireless devices that can retrieve multimedia content such as video and audio streams, still images, and scalar sensor data from the environment. In this paper, ongoing research on prototypes of multimedia sensors and their integration into testbeds for experimental evaluation of algorithms and protocols for WMSNs are described. Furthermore, open research issues and future research directions, both at the device level and at the testbed level, are discussed. This paper is intended to be a resource for researchers interested in advancing the state-of-the-art in experimental research on wireless multimedia sensor networks.

Wireless Multimedia Sensor Networks: Applications and Testbeds

A general and comprehensive analysis on the continuous contact force models for soft materials in multibody dynamics is presented throughout this work. The force models are developed based on the foundation of the Hertz law together with a hysteresis damping parameter that accounts for the energy dissipation during the contact process. In a simple way, these contact force models are based on the analysis and development of three main issues: (i) the dissipated energy associated with the coefficient of restitution that includes the balance of kinetic energy and the conservation of the linear momentum between the initial and final instant of contact; (ii) the stored elastic energy, representing part of initial kinetic energy, which is evaluated as the work done by the contact force developed during the contact process; (iii) the dissipated energy due to internal damping, which is evaluated by modeling the contact process as a single degree-of- freedom system to obtain a hysteresis damping factor. This factor takes into account the geometrical and material properties, as well as the kinematic characteristics of the contacting bodies. This approach has the great merit that can be used for contact problems involving materials with low or moderate values of coefficient of restitution and, therefore, accommodate high amount of energy dissipation. In addition, the resulting contact force model is suitable to be included into the equations of motion of a multibody system and contributes to their stable numerical resolution. A demonstrative example of application is used to provide the results that support the analysis and discussion of procedures and methodologies described in this work.

/pdf/on-the-continuous-contact-force-models-for-soft-materials-in-38io7v5muo.pdf

On the continuous contact force models for soft materials in multibody dynamics

Simulation has been the dominant research method- ology in wireless and sensor networking. When mobility is added, real-world experimentation is especially rare. However, it is becoming clear that simulation models do not sufficiently capture radio and sensor irregularity in a complex, real-world environment, especially indoors. Unfortunately, the high labor and equipment costs of truly mobile experimental infrastructure present high barriers to such experimentation. We describe our experience in creating a testbed to lower those barriers. We have extended the Emulab network testbed software to provide the first remotely-accessible mobile wireless and sensor testbed. Robots carry motes and single board computers through a fixed indoor field of sensor-equipped motes, all running the user's selected software. In real-time, interactively or driven by a script, remote users can position the robots, control all the computers and network interfaces, run arbitrary programs, and log data. Our mobile testbed provides simple path planning, a vision-based tracking system accurate to 1 cm, live maps, and webcams. Precise positioning and automation allow quick and painless evaluation of location and mobility effects on wireless protocols, location algorithms, and sensor-driven applications. The system is robust enough that it is deployed for public use. We present the design and implementation of our mobile testbed, evaluate key aspects of its performance, and describe a few experiments demonstrating its generality and power.

/pdf/mobile-emulab-a-robotic-wireless-and-sensor-network-testbed-a3xomds1wz.pdf

Mobile Emulab: A Robotic Wireless and Sensor Network Testbed

This paper presents a new dissipation principle for resolving post-impact tangential velocities after simultaneous impact events on a system composed of interconnected rigid bodies. In this work, contact is considered as a succession of impacts so that simultaneous contacts and impacts can be treated using the same framework. This treatment includes Coulomb friction and considers hard impacts where deformation of the impacting surfaces is negligible. The impact problem is addressed using the complementarity conditions which lead to an investigation of the relationship between post-impact velocities and feasible coefficients of friction. These conditions do not define a unique post-impact velocity so a dissipation principle is proposed which is encoded as an optimization problem. This solution preserves the discontinuity between the static and dynamic coefficients of friction. The approach is illustrated on a bicycle-like structure with elliptical wheels.

Simultaneous oblique impacts and contacts in multibody systems with friction

This paper presents a methodology for treating energy consistency when considering simultaneous impacts and contacts with friction in the simulation of systems of interconnected bodies. Hard impact and contact is considered where deformation of the impacting surfaces is negligible. The proposed approach uses a discrete algebraic model of impact in conjunction with moment and tangential coefficients of restitution (CORs) to develop a general impact law for determining post-impact velocities. This process depends on impulse–momentum theory, the complementarity conditions, a principle of maximum dissipation, and the determination of contact forces and post-impact accelerations. The proposed methodology also uses an energy-modifying COR to directly control the system’s energy profile over time. The key result is that different energy profiles yield different results and thus energy consistency should be considered carefully in the development of dynamic simulations. The approach is illustrated on a double pendulum, considered to be a benchmark case, and a bicycle structure.

Energetically consistent simulation of simultaneous impacts and contacts in multibody systems with friction

We have extended the well-known Emulab network testbed software to support both fixed and mobile wireless sensor devices. Mobility is achieved through remotely-controlled robots. We have deployed this software in public production use for the research and education communities. The current temporary testbed is in a 60 square meter indoor area. It contains six robots and 25 fixed Mica2 motes with serial programming boards, 10 of which also have full sensor boards. The robots carry an Intel Stargate with an X-Scale 400MHz CPU running Linux, an 802.11a/b/g wireless Ethernet card, and a Mica2. A much larger testbed is contemplated. Robot motion can be scripted using the ns language or interactively controlled from a Java applet Webcam views integrated into the applet ease remote access. A high-precision (1cm) localization system provides precise positions of robots (and thus wireless antennae). Users have full control over the wireless devices on each robot, and can install custom software on the Stargate and mote. To provide users with precise, real-time robot control, we extended the core of Emulab with three new components. The robot control daemon, robotd, maneuvers robots to user-specified positions based on input from visiond, and

Emulab's wireless sensor net testbed: true mobility, location precision, and remote access

Teleoperated robots generally receive high level commands from a remote system, while accomplishing motion control through conventional means. We present a teleoperated system that removes the entire motion control structure from the robot, in order to preserve the availability of crucial onboard resources. The operation of state feedback control is performed by a system remote from the robot. We have designed a computerized motion planning and control system for Mobile Emulab, and in this article, discuss the implementation of trajectory tracking control. A component of the Emulab network testbed, Mobile Emulab is used for wireless network experiments requiring mobility; and is publicly available to remote researchers via the Internet. Medium scale wheeled mobile robot couriers are used to move wireless antennas within a semi-controlled environment. Experimenters use a Web-based GUI to specify desired paths and configurations for multiple robots. State feedback is provided by an overhead camera based visual localization system. Kinematic control is used to generate velocity commands, which are sent to robots over a computer network. Data availability is restricted to a low sampling frequency. There is significant noise, loss, and phase lag present in the robot localization data, which our research overcomes to provide an autonomous trajectory tracking mobile robot control system.

/pdf/remote-low-frequency-state-feedback-kinematic-motion-control-4g9t2it152.pdf

Daniel Montrallo Flickinger

Papers

Mobile Emulab: A Robotic Wireless and Sensor Network Testbed

Simultaneous oblique impacts and contacts in multibody systems with friction

Energetically consistent simulation of simultaneous impacts and contacts in multibody systems with friction

Emulab's wireless sensor net testbed: true mobility, location precision, and remote access

Remote Low Frequency State Feedback Kinematic Motion Control for Mobile Robot Trajectory Tracking