Simple rules, when executed by individual agents in a large group, or swarm, can lead to complex behaviors that are often difficult or impossible to predict knowing only the rules. However, aggregate behavior is not always unpredictable-even for swarm models said to be beyond analysis. For the class of swarming algorithms examined herein, we analytically identify several possible emergent behaviors and their underlying causes: clustering, drifting, and explosion. They also analyze the likelihood of these behaviors emerging from randomly selected swarm configurations and present a few examples. The analytic results are illustrated via simulation.

Real-time computing platforms are ubiquitous in the fields of automation, robotics and control. These are often based on a real-time operating system that offers a high level of determinism to support processes such as discrete-event and feedback control. Using methods derived the theory of dynamic systems on time scales, this paper discusses through modeling and simulation the effects of non-determinism. The paper's conclusion supports the hypothesis that strict determinism is not always required to obtain adequate overall system performance.

This paper presents a method by which controllers operating on real-time networks such as the Controller Area Network (CAN) can reduce their bandwidth requirements in response to periods of high network traffic from sporadic sources. The method derives from advances in the theory of dynamic systems on time scales.

Continuum manipulators are robotic manipulators built using one continuous, elastic, and highly deformable "backbone" instead of multiple rigid links connected by joints. This paper extends a previous control result for planar continuum robots by proposing a new asymptotic convergence argument for a PD-plus-feedforward controller. The benefit of the asymptotic arguments is that the backbone bending stiffness can be adaptively updated by the controller if it is not known a priori.

Continuum manipulators are robotic manipulators built using one continuous, elastic and highly deformable "backbone", instead of multiple rigid links and joints. In previous work (2000), we illuminated various kinematic and dynamic properties of continuum robots, but the question of controller design remained open. This paper presents a basic result for continuum robots that has long been known for rigid-link robots: a simple PD-plus-feedforward controller can exponentially regulate the position of a manipulator.

Continuum manipulators, inspired by the natural capabilities of elephant trunks and octopus tentacles, may find niche applications in areas like human-robot interaction, multiarm manipulation, and unknown environment exploration. However, their true capabilities will remain largely inaccessible without proper analytical tools to evaluate their unique properties. Ellipsoids have long served as one of the foremost analytical tools available to the robotics researcher, and the purpose of this paper is to first formulate, and then to examine, three types of ellipsoids for continuum robots: manipulability, force, and compliance.

We focus on a class of robotic manipulators that utilize continuous backbone structures. Such manipulators, known as "continuum" robots, exhibit behavior similar to tentacles, trunks, and snakes. Specifically, we have previously discussed some of the mechanical and kinematic details of the Clemson -Tentacle Manipulator." This work examines the dynamic characteristics of this manipulator, proposing a vibration damping control strategy for configurations with the worst vibration characteristics. We begin by formulating the dynamics for one section of the Tentacle Manipulator. We then proceed to develop a vibration control strategy which incorporates a setpoint regulator. We supplement the theoretical developments with experimental results.

Manipulability and force ellipsoids have long been a useful tool for analyzing the relative capabilities of robotic, manipulators to move in, or to exert forces in, certain directions. The purpose of this paper is to first formulate, and then to examine, the manipulability and force ellipsoids for continuum robots. Continuum robots have continuously flexible backbones; consequently, their infinite-dimensional kinematics present special challenges in the formulation and interpretation of ellipsoids.

We consider a class of robotic manipulators generally termed "hyper-redundant". Specifically, we seek to examine some of the kinematic properties of "continuum" hyper-redundant robots. Unlike the case with rigid-link robots, there is no commonly accepted formula for describing continuum robot kinematics. Although these manipulators are continuously flexible, they are actuated with a finite number of actuators. We discuss two possible options for mapping desired infinite-dimensional robot shapes to the finite-dimensional actuator space, using "natural" and "wavelet" decompositions. We compare and contrast these kinematic descriptions, illustrating how the wavelet decomposition can simplify the inverse kinematics for redundant planar continuum robots.

Over the past several years, there has been a rapidly expanding interest in the study and construction of a new class of robot manipulators which utilize high degree of freedom, or continuous, backbone structures. In this paper, we consider and illustrate some basic properties of a class of "hyper-redundant" robots, known as "continuum" robots. We base our analysis around remotely-driven, tendon-actuated manipulators, such as the Rice/Clemson "Elephant's Trunk". We discuss such issues as the kinematic model, the relationship between tendon lengths and bending, and desirable design constraints for continuum robot mechanisms.

There exist in robotics, as in many other disciplines, problems described by an underdetermined set of constraints, possessing an infinite number of solutions. The problem of robot manipulator redundancy resolution is just such a situation, requiring that a particular solution be chosen according to some type of optimization criterion. One possibility employs a type of optimization which minimizes the maximum magnitude of the solution vector. This is the minimum infinity norm solution, also known as the "minimum effort solution." The paper explores the details of least infinity norm optimization, using kinematic redundancy resolution as a test case to explore the details of infinity-norm optimization. We introduce for the first time a closed-form expression for minimum effort solutions, illustrating the heretofore unknown properties of nonuniqueness and discontinuity in time-varying situations, and postulating a possible remedy for the discontinuity problem. Additionally, to reinforce the mathematics, simulations of four-link robots are included, as well as an extended discussion of minimum-effort solutions from a geometric point of view.

In this paper, we describe the hardware and control architecture of a novel four-fingered dextrous robot hand. The benefits of the unusual arrangement of the fingers (which resembles that in raptors and other birds) in the hand are discussed. Kinematic models for the fingers and transmission system are presented. A simulation and real-time control environment has been developed for the hand, and is discussed in the paper. Experiments in dextrous and dynamic manipulation using the hand are also detailed.

There are numerous situations in robotics where it becomes desirable to minimize the maximum magnitude of a solution to an underdetermined set of linear equations. For example, there have been several approaches to finding the joint velocities of kinematically redundant robots using this philosophy. Unfortunately, the solution of this optimization problem, known as the "minimum infinity-norm solution", cannot be expressed in a closed form in general thus requiring the use of an algorithm to iteratively refine an initial guess before reaching the desired solution. In order to increase our understanding and reduce the complexity of infinity-norm algorithms, we first formulate a new "infinity inverse", and then use the new inverse to explore critical issues such as uniqueness and continuity of least infinity-norm solutions. The new inverse is compared with the well-known pseudoinverse, or minimum two-norm solution. We discuss when and why one particular norm might produce a better solution than the other, reinforcing the discussion with an interesting example of a kinematically redundant manipulator.