A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

This paper presents control and coordination algorithms for groups of vehicles. The focus is on autonomous vehicle networks performing distributed sensing tasks where each vehicle plays the role of a mobile tunable sensor. The paper proposes gradient descent algorithms for a class of utility functions which encode optimal coverage and sensing policies. The resulting closed-loop behavior is adaptive, distributed, asynchronous, and verifiably correct.

Coverage control for mobile sensing networks

Bilateral teleoperation: An historical survey

Control methodologies in networked control systems

This paper addresses the problem of coordinating multiple spacecraft to fly in tightly controlled formations. The main contribution of the paper is to introduce a coordination architecture that subsumes leader-following, behavioral, and virtual-structure approaches to the multiagent coordination problem. The architecture is illustrated through a detailed application of the ideas to the problem of synthesizing a multiple spacecraft interferometer in deep space.

/pdf/a-coordination-architecture-for-spacecraft-formation-control-4svhkbrfe5.pdf

A coordination architecture for spacecraft formation control

Wireless Sensor Networks (WSNs) have become a leading solution in many important applications such as intrusion detection, target tracking, industrial automation, smart building and so on. Typically, a WSN consists of a large number of small, low-cost sensor nodes that are distributed in the target area for collecting data of interest. For a WSN to provide high throughput in an energy-efficient way, designing an efficient Medium Access Control (MAC) protocol is of paramount importance because the MAC layer coordinates nodes' access to the shared wireless medium. To show the evolution of WSN MAC protocols, this article surveys the latest progresses in WSN MAC protocol designs over the period 2002-2011. In the early development stages, designers were mostly concerned with energy efficiency because sensor nodes are usually limited in power supply. Recently, new protocols are being developed to provide multi-task support and efficient delivery of bursty traffic. Therefore, research attention has turned back to throughput and delay. This article details the evolution of WSN MAC protocols in four categories: asynchronous, synchronous, frame-slotted, and multichannel. These designs are evaluated in terms of energy efficiency, data delivery performance, and overhead needed to maintain a protocol's mechanisms. With extensive analysis of the protocols many future directions are stated at the end of this survey. The performance of different classes of protocols could be substantially improved in future designs by taking into consideration the recent advances in technologies and application demands.

The Evolution of MAC Protocols in Wireless Sensor Networks: A Survey

Distributed multi-robot coordination in area exploration

The paper is devoted to the problem of controlling a robot manipulator for a class of constrained motions. The task under consideration is to control the manipulator, such that the end-effector follows a path on an unknown surface, with the aid of a single camera assumed to be uncalibrated with respect to the robot coordinates. To accomplish a task of this kind, we propose a new control strategy based on multisensor fusion. We assume that three different sensors-that is, encoders mounted at each joint of the robot with six degrees of freedom, a force-torque sensor mounted at the wrist of the manipulator, and a visual sensor with a single camera fixed to the ceiling of the workcell-are available. Also, we assume that the contact point between the tool grasped by the end-effector and the surface is frictionless. To describe the proposed algorithm that we have implemented, first we decouple the vector space of control variables into two subspaces. We use one for controlling the magnitude of the contact force on the surface and the other for controlling the constrained motion on the surface. This way, the control synthesis problem is decoupled and we are able to develop a new scheme that utilizes sensor fusion to handle uncalibrated parameters in the workcell, wherein the surface on which the task is to be performed is assumed to be visible, but has an a priori unknown position.

http://cbcis.ttu.edu/lab_papers_books/open_content/open_papers/mv/XIAO_GHOSH_XI_TARN_2000.pdf

Sensor-based hybrid position/force control of a robot manipulator in an uncalibrated environment

A closed-loop control system that remotely controls a device over a distributed communications system includes a device that is connected to the distributed communications system and that generates super-media feedback signals. A computer is connected to the distributed communications system and includes a controller that provides super-media feedback. The computer generates and transmits command signals using the controller to the device and outputs the super-media feedback signals to the controller. The closed-loop control system is event-based to ensure stability and synchronization of the closed-loop system.

Synchronization and task control of real-time internet based super-media

The ability to jump is found widely among small animals such as frogs, grasshoppers, and fleas. They jump to overcome large obstacles relative to their small sizes. Inspired by the animals' jumping capability, a miniature jumping robot-Michigan State University (MSU) Jumper-has been developed. In this paper, the mechanical design, fabrication, and experimentation of the MSU jumper are presented. The robot can achieve the following three performances simultaneously, which distinguish it from the other existing jumping robots. First, it can perform continuous steerable jumping that is based on the self-righting and the steering capabilities. Second, the robot only requires a single actuator to perform all the functions. Third, the robot has a light weight (23.5 g) to reduce the damage that results from the impact of landing. Experimental results show that, with a 75° take-off angle, the robot can jump up to 87 cm in vertical height and 90 cm in horizontal distance. The robot has a wide range of applications such as sensor/communication networks, search and rescue, surveillance, and environmental monitoring.

/pdf/msu-jumper-a-single-motor-actuated-miniature-steerable-3pxf0g4qq5.pdf

Ning Xi

Papers

The Evolution of MAC Protocols in Wireless Sensor Networks: A Survey

Distributed multi-robot coordination in area exploration

Sensor-based hybrid position/force control of a robot manipulator in an uncalibrated environment

Synchronization and task control of real-time internet based super-media

MSU Jumper: A Single-Motor-Actuated Miniature Steerable Jumping Robot