There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

In this book, Andrew Harvey sets out to provide a unified and comprehensive theory of structural time series models. Unlike the traditional ARIMA models, structural time series models consist explicitly of unobserved components, such as trends and seasonals, which have a direct interpretation. As a result the model selection methodology associated with structural models is much closer to econometric methodology. The link with econometrics is made even closer by the natural way in which the models can be extended to include explanatory variables and to cope with multivariate time series. From the technical point of view, state space models and the Kalman filter play a key role in the statistical treatment of structural time series models. The book includes a detailed treatment of the Kalman filter. This technique was originally developed in control engineering, but is becoming increasingly important in fields such as economics and operations research. This book is concerned primarily with modelling economic and social time series, and with addressing the special problems which the treatment of such series poses. The properties of the models and the methodological techniques used to select them are illustrated with various applications. These range from the modellling of trends and cycles in US macroeconomic time series to to an evaluation of the effects of seat belt legislation in the UK.

Forecasting, Structural Time Series Models and the Kalman Filter

(1991). Applied Linear Regression Models. Journal of Quality Technology: Vol. 23, No. 1, pp. 76-77.

Applied Linear Regression Models

Bilateral teleoperation: An historical survey

In this paper, the iterative learning control (ILC) literature published between 1998 and 2004 is categorized and discussed, extending the earlier reviews presented by two of the authors. The papers includes a general introduction to ILC and a technical description of the methodology. The selected results are reviewed, and the ILC literature is categorized into subcategories within the broader division of application-focused and theory-focused results.

Iterative Learning Control: Brief Survey and Categorization

Regulation d'effort et de position d'un manipulateur durant l'execution de mouvements avec contraintes

Force and position control of manipulators during constrained motion tasks

Trajectory control of a manipulator constrained by the contact of the end-effector with the environment represents an important class of control problems. A method is proposed whereby both contact force exerted by the manipulator, and the position of the end-effector while in contact with the surface are controlled. The controller parameters are derived based on a linearized dynamic model of the manipulator during constrained motion. Hence the method is valid only in a neighborhood about the point of linearization. Additionally, a perfect kinematic model of the contact surface is assumed. The proposed method utilizes the fundamental structure of the dynamic formulation of the manipulator's constrained motion. With this formulation, the trajectory control problem is naturally expressed in terms of the state vector variables of the model of the constrained dynamic system. A detailed numerical example illustrates the proposed method. >

This paper describes a novel microassembly system that can be used to construct out-of-plane three-dimensional (3-D) microstructures. The system makes use of a surface-micromachined microgripper that is solder bonded to a robotic manipulator. The microgripper is able to grasp a micropart, remove it from the chip, reorient it about two independent axes, translate it along the x, y and z axes to a secondary location, and join it to another micropart. In this way, out-of-plane 3-D microstructures can be assembled from a set of initially planar and parallel surface micromachined microparts. The microgripper is 380 /spl times/ 410 /spl mu/m in size. It utilizes three geometric features for operation: 1) compliant beams to allow for deflection at the grasping tips; 2) self-tightening geometry during grasping; and 3) 3-D interlocking geometry to secure a micropart after the grasp. Each micropart has three geometric features built into its body. The first is the interlock interface feature that allows it to be grasped by the microgripper. The second is a tether feature that secures the micropart to the substrate, and breaks away after the microgripper has grasped the micropart. The third is the snap-lock feature, which is used to join the micropart to other microparts.

/pdf/microassembly-of-3-d-microstructures-using-a-compliant-1051gg5t1u.pdf

Microassembly of 3-D microstructures using a compliant, passive microgripper

Coordination of multirobot systems has received extensive studies in the past decade. The majority of previous approaches require a complex setup of the hybrid position/force-control architecture, and have not fully addressed the coordination problem when the robots are not kinematically constrained but perform a common task. In this paper, we propose to use a new coordination scheme that is more straightforward and easier to implement and is applicable to a wider area. The basic idea of the new coordination strategy is to use the concept of motion synchronization, since the problem of coordinating multiple manipulators is basically the problem of maintaining certain kinematic relationships amongst robots. The key to the success of the new method is to ensure that each manipulator tracks its desired trajectory while synchronizing its motion with other manipulators' motions, so that differential (or synchronization) position errors amongst manipulators converge to zero. The controller, designed by incorporating the cross-coupling technology into an adaptive-control architecture, successfully guarantees asymptotic convergence to zero of both position tracking and synchronization errors simultaneously. Experiments and simulations on multirobot assembly systems demonstrate the effectiveness of the approach.

Adaptive synchronized control for coordination of multirobot assembly tasks

Biological cell injection is laborious work that requires lengthy training and suffers from a low success rate. In this paper, a robotic cell-injection system for automatic injection of batch-suspended cells is proposed. To facilitate the process, these suspended cells are held and fixed to a cell array by a specially designed cell-holding device, and injected one by one through an ldquoout-of-planerdquo cell-injection process. A micropipette equipped with a polyvinylidene fluoride microforce sensor to measure real-time injection force is integrated in the proposed system. Through calibration, an empirical relationship between the cell-injection force and the desired injector pipette trajectory is obtained in advance. Then, after decoupling the out-of-plane cell injection into a position control in the X - Y horizontal plane and an impedance control in the Z -axis, a position and force control algorithm is developed to control the injection pipette. The depth motion of the injector pipette, which cannot be observed by microscope, is indirectly controlled via the impedance control, and the desired force is determined from the online X - Y position control and cell calibration results. Finally, experimental results demonstrate the effectiveness of the proposed approach.

James K. Mills

Papers

Force and position control of manipulators during constrained motion tasks

Force and position control of manipulators during constrained motion tasks

Microassembly of 3-D microstructures using a compliant, passive microgripper

Adaptive synchronized control for coordination of multirobot assembly tasks

Robotic Cell Injection System With Position and Force Control: Toward Automatic Batch Biomanipulation