John Baruch

Indirect Iterative Learning Control for a Discrete Visual Servo Without a Camera-Robot Model

This paper presents a discrete learning controller for vision-guided robot trajectory imitation with no prior knowledge of the camera-robot model. A teacher demonstrates a desired movement in front of a camera, and then, the robot is tasked to replay it by repetitive tracking. The imitation procedure is considered as a discrete tracking control problem in the image plane, with an unknown and time-varying image Jacobian matrix. Instead of updating the control signal directly, as is usually done in iterative learning control (ILC), a series of neural networks are used to approximate the unknown Jacobian matrix around every sample point in the demonstrated trajectory, and the time-varying weights of local neural networks are identified through repetitive tracking, i.e., indirect ILC. This makes repetitive segmented training possible, and a segmented training strategy is presented to retain the training trajectories solely within the effective region for neural network approximation. However, a singularity problem may occur if an unmodified neural-network-based Jacobian estimation is used to calculate the robot end-effector velocity. A new weight modification algorithm is proposed which ensures invertibility of the estimation, thus circumventing the problem. Stability is further discussed, and the relationship between the approximation capability of the neural network and the tracking accuracy is obtained. Simulations and experiments are carried out to illustrate the validity of the proposed controller for trajectory imitation of robot manipulators with unknown time-varying Jacobian matrices.

Robots in astronomy

Abstract This paper follows the growth of robotics and automation in industry and astronomy. It discusses the different purposes for which automation is used in observational astronomy and compares the problems of robot development in industry with the experiences in astronomy. The disillusionment with robotics after the excitement and promise of the sixties is evaluated. Modern ideas of the robot as a personal assistant are developed for application in astronomy. The paper discusses how technology steers our direction of investigations in astronomy, and colours our views of the universe. It is argued that robotics in astronomy will open up whole new areas of investigation that are as likely to be as surprising and exciting as many other new avenues which astronomy has taken. It reviews the most fertile areas for robotic observing and develops an outline design. The necessary technological developments for specific types of observational investigations are detailed. Current programmes of robotic and automated telescopes are listed and the case made for international cooperation to agree formats, interfaces and standards. With standard data formats robotic telescopes can be a world resource that can be addressed by any observer, robotic or human. Standard interfaces will ensure that robotic systems can be broken down into units, particularly software units, that can be made freely available to encourage collaboration. Alternatively new software can be developed to link to standard interfaces by those who wish to improve the systems and compete. The paper concludes with a brief look at the future for robotic systems in astronomy.

A Template Model for Defect Simulation for Evaluating Nondestructive Testing in X-Radiography

This paper proposes a new template model for the simulation of casting defects which are classified, according to shape, into three main types: the single defect with circular or elliptical shape, shrinkage defects with stochastic discontinuities, and the cavity or sponge shrinkage defects. For effective simulation, different nesting stencil plates are designed to reflect the characteristics of different casting defects. These include intensity, orientation, size, and shape. The proposed approach also uses geometric diffusion to demonstrate the production of simulated defects with effective shading and contrast when compared to their background. In order to evaluate the effectiveness of the proposed approach, the simulated casting defects are superposed on real radioscopic images of casting pieces and compared with real defects by extensive visual inspection. On the other hand, in order to verify the similarity of the simulated defects and the real defects, we have used our defect inspection algorithm to recognize both real and simulated defects in the same image. The experimental results show that the proposed defect simulation approach can produce a large range of simulated casting defects, which can be utilized as sample images to tune the parameters of casting inspection algorithms.

A Mosaic of Eyes

Autonomous navigation is a traditional research topic in intelligent robotics and vehicles, which requires a robot to perceive its environment through onboard sensors such as cameras or laser scanners, to enable it to drive to its goal. Most research to date has focused on the development of a large and smart brain to gain autonomous capability for robots. There are three fundamental questions to be answered by an autonomous mobile robot: 1) Where am I going? 2) Where am I? and 3) How do I get there? To answer these basic questions, a robot requires a massive spatial memory and considerable computational resources to accomplish perception, localization, path planning, and control. It is not yet possible to deliver the centralized intelligence required for our real-life applications, such as autonomous ground vehicles and wheelchairs in care centers. In fact, most autonomous robots try to mimic how humans navigate, interpreting images taken by cameras and then taking decisions accordingly. They may encounter the following difficulties.

A gamma ray telescope for the highest energies using radio waves

This paper considers the possibility of using pulsed and continuous wave radio sources to scatter or reflect a signal from the ionisation produced by an Extensive Air Shower (EAS) to provide a precise indication of the source co-ordinates of the primary gamma ray. It indicates the limits of such methods and suggests a route which may result in a significant improvement in the current precision of cosmic gamma ray source coordinates.

Robotic telescope systems for CCD photometry of faint objects in crowded fields

This paper first considers the design of robotic telescopes to monitor faint objects in crowded fields. It shows that the mechanical design problems have been solved by the use of precision control and modelling software developed for the latest large telescopes. Modern design methods mean that these telescopes can be produced relatively cheaply. The largest part of the cost of a robotic telescope is the software to enable it to work as an autonomous robot. Conventional software techniques are inadequate and inefficient for many purposes associated with robotic operation. These include: to optimize and monitor their operation and efficiency, to schedule their observing, to evaluate their environment, to generate confidence in the target acquisition pattern recognition parameters, to evaluate the quality of the CCD images and the photometry of the objects within the images, and to return reduced data to the astronomer with the required indices to gives the astronomer confidence in the data. The paper evaluates AI, neural nets and fuzzy logic techniques applied to these different problems.

Outreach at the match: a cautionary tale

John Baruch, Ulrich Kolb, Helen Fraser and Jen Heyes share some of the pitfalls they encountered when combining outreach with football; they advocate a different sort of wow factor.

Olympic games in China

John Baruch visited China for the Astronomy Olympiad and found young people eager to excel in astronomy in future.

Basic astronomy as part of a general higher education in the developing world

This paper describes a new initiative in support of the aim of Commission 46 of the IAU to develop and improve astronomy education at all levels throughout the world. This paper discusses the ideal specification of a facility to support basic astronomy within education programmes which are delivered to students who have access to the Internet. The available robotic telescopes are discussed against this specification and it is argued that the Bradford Robotic Telescope, uniquely, can support many thousands of users in the area of basic astronomy education, and the resource is free. Access to the Internet is growing in the developing world and this is true in education programmes. This paper discusses the serious problems of delivering to large numbers of students a web based astronomy education programme supported by a robotic telescope as part of a general education. It examines the problems of this form of teaching for teachers who have little experience of working with IT and little knowledge of basic astronomy and proposes how such teachers can be supported. The current system ( http://www.telescope.org/ ) delivers astronomy education in the language, culture and traditions of England. The paper discusses the need to extend this to other languages, cultures and traditions, although for trainee teachers and undergraduates, it is argued that the current system provides a unique and valuable resource.

The Future of Automated Telescopes and the Bradford Robotic Telescopes

Robotic telescopes have evolved through the development of technologies, which started with precision electronic clocks, computers and intensified TV cameras. The development lines of robotic telescopes are outlined and the major applications for the different areas of astronomy are discussed. Just as precision electronic clocks made robotic astronomy possible they also destroyed the major national reason for the support of astronomy: the keeping of time. Now robotic astronomy has developed new reasons for a national interest in its development and support: access to the stars for school students to excite them with the physical sciences and encourage them into a career in engineering, physics, mathematics, computing or technology.