Proportional-Integral-Plus Control Strategy of an Intelligent Excavator

This article considers the application of Proportional-Integral-Plus (PIP) control to the Lancaster University Computerised Intelligent Excavator (LUCIE), which is being developed to dig foundation trenches on a building site. Previous work using LUCIE was based on the ubiquitous PI/PID control algorithm, tuned on-line, and implemented in a rather ad hoc manner. By contrast, the present research utilizes new hardware and advanced model-based control system design methods to improve the joint control and so provide smoother, more accurate movement of the excavator arm. In this article, a novel nonlinear simulation model of the system is developed for MATLAB/SIMULINK, allowing for straightforward refinement of the control algorithm and initial evaluation. The PIP controller is compared with a conventionally tuned PID algorithm, with the final designs implemented on-line for the control of dipper angle. The simulated responses and preliminary implementation results demonstrate the feasibility of the approach

Automating the construction workplace: positioning and navigational factors.

The adaptation of conventional robots to construction sites is fraught with problems. Most significant of these are in relation to positioning, means of collision avoidance, and appropriate navigation strategy. This paper reviews the different levels of navigational autonomy that are possible and describes the system requirements for each. A taxonomy based on the concept of a Mobility Automation Level (MAL) is proposed. Each level is described and the requirements from a robot design perspective are discussed. Finally, a case study, based on an excavator with autonomously optimised movement, known as LUCIE, is used to illustrate some of the design criteria previously described and discussed

Graphical programming and the development of construction robots.

Complexity, multidisciplinarity, and algorithmic inherency are characteristics of construction robotic systems. Controlling the development process of such systems requires the adoption of a development model based on Systems Engineering principles. The software-development process is an important aspect of the system, which requires a development environment that can cope with this complexity. Using traditional programming languages (textual) requires highly trained programmers for this purpose, which involves high cost and long development time. In the present work Graphical Programming (iconic) is used as the software development environment because it is highly modular and allows concurrent development, both of which save on time and cost. It also enables nonexpert programmers to produce software capable of coping with the system complexity. A detailed case study of the software development process for an existing tool manipulation robot known as Starlifter is presented. Use of the LabVIEW package is demonstrated for both onboard system control and off-line project management

The Use of Robotics and Automation in Nuclear Decommissioning

Abstract-The paper reviews the scope for automation and robotics in the rapidly expanding field of nuclear decommissioning. The basic strategies for decommissioning are discussed together with the essential physical steps. The role that automation and robotics can play in enabling quicker demolition and at the same time reducing the exposure of workers to harmful radiation is discussed. The key issues surrounding radioactive materials and safe dose levels are explained. Examples of a wide range of recently developed automated technologies are provided. The paper will conclude by describing those areas that are currently the subject research and development