David W. Hainsworth

Teleoperation User Interfaces for Mining Robotics

This paper presents a brief discussion of the requirements for user interfaces for teleoperation of mining vehicles and systems. Current commercial interfaces are relatively simple, evolving from line-of-sight remote control systems with the addition of video displays. This level of sophistication has nonetheless allowed teleoperation to be a viable and profitable technique. CSIRO Exploration and Mining research into interface design currently concentrates on fusion of non-visual feedback to the operator and efficient presentation of such information. Case studies based on user interfaces for two experimental teleoperated mining-related systems, the Numbat mine emergency response vehicle and remote highwall mining control systems are described. In both cases the purpose of the user interface is to satisfy the major client requirements for mining systems of robustness, reliability and ease of use by site operational and support personnel.

Longwall mining automation an application of minimum-variance smoothing [Applications of Control]

This article reviews the development of the minimum-variance smoother and describes its use in longwall automation. We describe both continuous- and discrete-time smoother solutions. It is shown, under suitable assumptions, that the two-norm of the smoother estimation error is less than that for the Kalman filter. A simulation study is presented to compare the performance of the minimum-variance smoother with the methods of H.E. Rauch et al. (1965), and D.C. Fraser and J.E. Potter (1969).

Optimizing Wireless LAN for Longwall Coal Mine Automation

A significant development in underground longwall coal mining automation has been achieved with the successful implementation of wireless LAN (WLAN) technology for communication on a longwall shearer. WIreless-FIdelity (Wi-Fi) was selected to meet the bandwidth requirements of the underground data network, and several configurations were installed on operating longwalls to evaluate their performance. Although these efforts demonstrated the feasibility of using WLAN technology in longwall operation, it was clear that new research and development was required in order to establish optimal full-face coverage. By undertaking an accurate characterization of the target environment, it has been possible to achieve great improvements in WLAN performance over a nominal Wi-Fi installation. This paper discusses the impact of Fresnel zone obstructions and multipath effects on radio frequency propagation and reports an optimal antenna and system configuration. Many of the lessons learned in the longwall case are immediately applicable to other underground mining operations, particularly wherever there is a high degree of obstruction from mining equipment

Localisation of mobile underground mining equipment using wireless Ethernet

This review paper explores the use of IEEE 802.11b wireless Ethernet for the localisation of mobile equipment operating in an underground coal mining environment wireless communication networks have recently been introduced with some success in underground operations such as longwall mining to provide reliable high-speed communications for monitoring and control. We investigate the feasibility of this wireless paradigm for providing a new machine localisation capability underground, as has been recently considered in other non-mining domains. We overview two popular location estimation techniques, namely nearest-neighbour and Monte-Carlo Localisation, which use only the signal strength as received from several wireless access points to estimate location. Because the received signal strength is a highly variable parameter in underground environments, real data experiments are conducted using an in-house test facility to investigate signal properties and to evaluate the potential of the concept for underground mining.

Riccati Equation and EM Algorithm Convergence for Inertial Navigation Alignment

This correspondence investigates the convergence of a Kalman filter-based expectation-maximization (EM) algorithm for estimating variances. It is shown that if the variance estimates and the error covariances are initialized appropriately, the underlying Riccati equation solution and the sequence of iterations will be monotonically nonincreasing. Further, the process noise variance estimates converge to the actual values when the measurement noise becomes negligibly small. Conversely, when the process noise variance becomes negligible, the measurement noise variance estimates asymptotically approach the true values. An inertial navigation application is discussed in which performance depends on accurately estimating the process variances.

Recent advances in remote coal mining machine sensing, guidance, and teleoperation

This paper presents some recent applications of sensing, guidance and telerobotic technology in the coal mining industry. Of special interest is the development of semi or fully autonomous systems to provide remote guidance and communications for coal mining equipment. We consider the use of radar and inertial based sensors in an attempt to solve the horizontal and lateral guidance problems associated with mining equipment automation. We also describe a novel teleoperated robot vehicle with unique communications capabilities, called the Numbat, which is used in underground mine safety and reconnaissance missions.

Application of ground penetrating radar for coal depth measurement

This paper describes the development of a new ground penetrating radar system for measuring coal thickness in underground mining operations. Although subsurface radar exhibits significant potential for depth measurement, the raw signals are complicated and cannot be readily interpreted by mining personnel. We show how real-time digital signal processing plays a key role in transforming the raw radar signals into a form that can be readily understood. We also indicate some of the unique challenges encountered when implementing a radar processing system in a harsh underground mining environment.

The Numbat: A Remotely Controlled Mine Emergency Response Vehicle

The Numbat is a remotely controlled vehicle used to convey information on the condition of underground mines in situations where it is too hazardous for manual exploration. The Numbat integrates a diverse range of communications, actuation, mobility, power, control and software technologies. This paper reports on technical aspects of the Numbat and describes how the management of technologies solves a range of practical problems.

Location of a dragline bucket in space using machine vision techniques

Because a dragline buckets rigging is flexible, its position cannot be inferred from knowledge of rope length and boom position only. Moreover, active devices cannot be placed on the bucket itself to sense position because of the risk of damage. This paper describes a new machine vision system which is being developed to sense bucket position remotely. It is based on a single camera observing the field in which the bucket moves. An image segmentation process is used to classify the bucket and to identify its position in the scene. This data is used to determine the angle between the bucket and the vertical boom plane, which is used as position feedback in a closed loop system to control bucket motion. The segmentation processes employed, based on colour and intensity are outlined, and experimental results are presented.<<ETX>>

Optimising wireless LAN for longwall coal mine automation

A significant development in underground longwall coal mining automation has been achieved with the successful implementation of WLAN technology for communication on a longwall shearer. Wi-Fi was selected to meet the bandwidth requirements of the underground data network, and several configurations were installed on operating longwalls to evaluate their performance. Although these efforts demonstrated the feasibility of using WLAN technology in a longwall operation, it was clear that new research and development was required in order to establish optimal, full face coverage. By undertaking an accurate characterisation of the target environment it has been possible to achieve great improvements in WLAN performance over a nominal Wi-Fi installation. The paper discusses the impact of Fresnel zone obstructions and multipath effects on RF propagation, as well as reporting on an optimal antenna and system configuration. Many of the lessons learnt in the longwall case are immediately applicable to other underground mining operations, particularly wherever there is a high degree of obstruction from mining equipment.