Real-Time Drilling Control for Hanging-Wall Stability: SCADA-Based Mitigation of Overbreak and Dilution in Long-Hole Stoping

Whereas numerous motor control theories describe the control of arm trajectory during reach, the control of stabilization in a constant arm position (i.e., visuomotor control of arm posture) is less clear. Three potential mechanisms have been proposed for visuomotor control of arm posture: 1) increased impedance of the arm through co-contraction of antagonistic muscles, 2) corrective muscle activity via spinal/supraspinal reflex circuits, and/or 3) intermittent voluntary corrections to errors in position. We examined the cortical mechanisms of visuomotor control of arm posture and tested the hypothesis that cortical error networks contribute to arm stabilization. We collected electroencephalography (EEG) data from 10 young healthy participants across four experimental planar movement tasks. We examined brain activity associated with intermittent voluntary corrections of position error and antagonist co-contraction during stabilization. EEG beta-band (13-26 Hz) power fluctuations were used as indicators of brain activity, and coherence between EEG electrodes was used as a measure of functional connectivity between brain regions. Cortical activity in the sensory, motor, and visual areas during arm stabilization was similar to activity during volitional arm movements and was larger than activity during co-contraction of the arm. However, cortical connectivity between the sensorimotor and visual regions was higher during arm stabilization compared with volitional arm movements and co-contraction of the arm. The difference in cortical activity and connectivity between tasks might be attributed to an underlying visuomotor error network used to update motor commands for visuomotor control of arm posture.NEW & NOTEWORTHY We examined cortical activity and connectivity during control of stabilization in a constant arm position (i.e., visuomotor control of arm posture). Our findings provide evidence for cortical involvement during control of stabilization in a constant arm position. A visuomotor error network appears to be active and may update motor commands for visuomotor control of arm posture.

Localization is a technique to determine the position of the robot in an environment. Robot positioning is a basic problem when designing a mobile robot. If the robot does not know its position, then the next robot action will be difficult to determine. To be able to determine the position of the omnidirectional robot requires good speed control on the DC motor. In omnidirectional robots, positioning is through the use of a rotary encoder sensor to count the movement of the omni robot at X and Y coordinates and the IMU sensor to maintain the direction of the robot facing. PID control is also applied to control the rotational speed of each DC motor on the robot wheel. Odometry is the method used in this study. The odometry system aims to estimate the position relative to the initial position of the omni robot to estimate the change in position from time to time. The final result of this research is the application of the odometry method based on a rotary encoder and IMU sensor can produce an effective and stable robot motion and can move in all directions (holonomic) by maintaining the robot's facing direction. The results of the test form simple motions such as forward, backward, right side, and left side motion, as well as forming a box trajectory that has a position error that is not large and quite accurate. The average error value at coordinate X is 1.44 cm and at coordinate Y is 1.67 cm.

Shaft inserting is important and frequent operation for the automatic parts assembling. We have developed a shaft inserting system for the moving object using the robot with a cross PSD sensor. This PSD sensor can detect the position error and the angle of the target hole in real time. In this paper, we show the detecting characteristics of the inclined angle of the target hole for the cross PSD. Also we show the system diagram of the robot system with the cross PSD sensor. Then we propose the shaft inserting algorithm. By using this system, the robot can insert a shaft into a hole of the moving object with the clearance of 50μm at a velocity of 40mm/s in the case of setting the inclined angle within 5 degree. Our proposed sensor based system is effective for the shaft inserting into the hole of the moving object.

The main roadblock to Atomic Force Microscope (AFM) based nanomanipulation is lack of real time visual feedback. Although the model based visual feedback can partly solve this problem, due to the complication of nano environment, it is difficult to accurately describe the behavior of nano-objects with a model. The modeling error will lead to an inaccurate feedback and a failed manipulation. In this paper, a Kalman filter is developed to real time detect this modeling error. During manipulation, the residual between the estimated behavior and the visual display behavior is real time updated. The residual's Mahalanobis distance is calculated and compared with an threshold to determine whether there is a position error. Once the threshold is exceeded, an alarm signal will be triggered to tell the system there is a position error. Furthermore, the position error can be on-line corrected by local scan method. With the assistance of Kalman filter and local scan, the position error not only can be real-time detected, but also can be online corrected. The visual display keeps matching with the real manipulation result during the whole manipulation process, which significantly improve the efficiency of the AFM based nano-assembly. Experiments of manipulating nano-particles are presented to verify the effectiveness of Kalman filter and local scan method.

The article deals with the developing and applying of the mobile mapping system developed at the Department of Surveying of the Slovak University of Technology in Bratislava. The article presents a low-cost mobile mapping system for simultaneous localization and mapping of the indoor environment. Existing systems are costly and have robust construction and high-power requirements, making them unavailable for some applications. The proposed measuring system consists of three orthogonally placed 2D lidars, a robotic platform with two rotary encoders, and an inertial measuring unit. The lidars scan the environment in three mutually perpendicular directions during the measurement. Based on the transformation between a pair of consecutive scans, the position of the system is updated. Then the model of the environment is updated using a new lidar scan. The estimated transformation parameters are translations expressing the change in position of the system and rotation, which represents the change in orientation of the measuring system. The errors in determining the transformation parameters represent the positioning errors, which are transmitted to the calculated model. For this reason, additional sensors are used (inertial measuring unit, speed sensors), based on which the error in position and orientation is corrected.

Some space-borne GNSS receivers, such as those used in non-geostationary satellite communication systems, require real time high integrity to ensure both real timing positioning and one pulse per second precision. Since the host satellites fly following the discipline of space dynamics, is it possible to monitor the receiver integrity by exploring orbital elements of the host satellites? In this work, the mathematical relationship between variations of orbital elements and positioning errors are derived. Accordingly, an autonomous integrity monitoring method for space-borne GNSS receivers based on deviations of semi-major axis is proposed. By monitoring the deviation of semimajor axis, which is a direct combination of the position and velocity error as indicated by our mathematical derivation, the proposed method does not rely on pseudorange and pseudorange rate residues as the existing methods. Simulations are conducted using the in-orbit GNSS data of the LingQiao satellite (NORAD ID: 40136). The results show the proposed method can effectively detect abnormal solutions.

In the present contribution, we address the use of continuous vibration measurements to detect rupture of wires in the tensile armor layers of flexible risers. The interest in structural health monitoring of these components of deep and ultradeep water petroleum production systems has been growing steadily in the last few years. For pipes that are already reaching the limit of their service life, monitoring systems may provide early warnings of failure and also assist the operator in optimizing maintenance stops or scheduling top end retermination operations. There are already a number of different techniques, such as the use of video cameras, fiber optic sensors, acoustic emission, or magnetic stress measurement, which are being tested or deployed in the field in order to monitor progressive failure of the armour wires. These techniques either provide direct measurements in the wires or indirect signals that allow the identification of rupture of single or multiples wires. Monitoring vibration falls in the latter category. As a wire in the external or internal layer of the tensile armour breaks, a very distinguishable vibration signal, both in frequency and amplitude, is picked up by accelerometers placed on the risers' outer sheath. In the paper we report results of four full scale tests that have demonstrated the feasibility of deploying the system in a first field trial. Results have shown that the probability of detection significantly increases when the vibration monitoring system is employed in conjunction with measurements of longitudinal and torsional strains in the outer sheath. We discuss the architecture and signal processing strategies that have been developed to implement the proposed vibration monitoring system in the field. Introduction One of the main mechanisms of failure in flexible risers is the disruption of the armour wire traction [1]. Experience has shown that this class of damage tends to occur primarily in the submerged part of the riser, close to its termination. The rupture of the wires occurs gradually and may be caused by different processes such as: corrosion by inflow of fluid in the annular space between the cover and armor, excessive deterioration associated with contact and friction between adjacent wires or between the different layers of metal armor or even the presence of high levels of stress produced by mechanical loads to which the riser is subjected during operation. The progressive deterioration can lead to localized defects that act as stress concentrators and lead the wire to break through a process of fatigue. The flexible duct can remain operational even with some of their armor broken wires [2,3], but a string of disruptions may lead to the occurrence of leaks or even catastrophic failures. The continuous monitoring, in real time, is one of the main alternatives to prevent the progressive damage to the armor of the riser resulting in accidents with severe environmental and economic consequences [4,5]. The vibration system presented in this paper was developed and tested by technological cooperation between the Petrobras Research Center (CENPES) and laboratories at PUC-Rio. In this article, the results of laboratory tests carried out with full-scale prototypes of these systems are described in good details.

In this study, we propose a real time inertial navigation system/global positioning system (INS/GPS) integrated smoothing algorithm based on an extended Kalman filter (EKF) and a position damping loop (PDL) for synthetic aperture radar (SAR). Integrated navigation algorithms usually induce discontinuities due to error correction update by the Kalman filter, which are as detrimental to the performance of SAR as the relative position error. The proposed smoothing algorithm suppresses these discontinuities and also reduces the relative position error in real time. An EKF estimates the navigation errors and sensor biases, and all the errors except for the position error are corrected directly and instantly. A PDL activated during SAR operation period imposes damping effects on the position error estimates, where the estimated position error is corrected smoothly and gradually, which contributes to the real time smoothing and small relative position errors. The residual errors are re-estimated by the EKF to maintain the estimation performance and the stability of the overall loop. The performance improvements were confirmed by Monte Carlo simulations. The simulation results showed that the discontinuities were reduced by 99.8% and the relative position error by 48% compared with a conventional EKF without a smoothing loop, thereby satisfying the basic performance requirements for SAR operation. The proposed algorithm may be applicable to low cost SAR systems which use a conventional INS/GPS without changing their hardware configurations.

Encoder based online motion planning and feedback control of redundant manipulators

The strength and consistency of cemented paste backfill (CPB) are of key concerns in the stope stability and cost control for underground mines. It is common practice to use additives, such as superplasticizer, to improve the performance of CPB. This study mainly focuses on the effects of superplasticizer on the hydration, consistency, and strength of CPB. In this study, a polynaphtalene sulfonate was used as the superplasticizer. The binder is a mix of 33.3% ordinary Portland cement and 66.7% fly ash. The CPB specimens with a tailings-binder ratio of 3:1 and a solid concentration of 70% were then tested by a low field nuclear magnetic resonance system after different hydration times. Effects of polynaphtalene sulfonate on the hydration, fluidity, and strength were investigated. Results showed that the polynaphtalene sulfonate has a strong influence on short-duration hydration, which may contribute to the strength increase of CPB. It has been demonstrated that the polynaphtalene sulfonate improved the fluidity of the CPB mixture. With the increased dosage of polynaphtalene sulfonate, the slump increased. It was also found that the polynaphtalene sulfonate dosage has a negligible effect on the 1 day (d) strength while it has a strengthening effect on the 7 d, 14 d, and 28 d strength of CPB specimens.

Drilling High-Angle Casing Directionally Drilled Wells With Fit-for-Purpose String Sizes

Vulnerability of bridges to fire

This paper describes the current equipment and techniques used to reciprocate and cement liners in Alaska's Prudhoe Bay Field. Liner reciprocation was started in Prudhoe Bay by BP Alaska, Inc., using hydraulic-set hangers during 1976. Liner reciprocation was initially developed to improve mud displacement thereby improving cement bonding in high-angle wells. To date, more than 210 deviated wells have been successfully completed using the methods described in this paper. Typical Prudhoe Bay Unit wells are completed with approximately 1,500 ft of 7 in. 29#/ft L-80 liner hung across 8-1/2 in. open hole at 10,800 ft MD in hole angles up to 67 degrees. Liners are routinely reciprocated while conditioning mud and while circulating and displacing cement slurries. The cement is preceded with a chemical or water pre-flush, and the entire slurry is displaced at turbulent flow rates. The hanger is hydraulically set with a liner wiper plug. Current technology includes the use of the latest recirculating cementing unit as well as liner hanger equipment designed for compactness, low-flow restriction, and high-load capacity. Reciprocating liners in the Prudhoe Bay Unit has resulted in a significant drop in the number of squeeze cement jobs of the liner and/or liner lap. Success has been verified by lap in-flow testing, low-water production rates, and a good cement bonding at the critical oil/ water and gas/oil contacts.

Robotic arms have been used in various processes such as for moving goods, welding, assembling, and painting. In the case of welding and painting, it is necessary to move the end-effector robot accurately and smoothly to follow the specified trajectory. In robotic arm control, 2 things are important to be analyzed and implemented in controlling the motion of the robotic arm, namely inverse kinematic and trajectory planning. In this study, the inverse kinematic and trajectory planning algorithms are implemented to the robotic arm controller in the form of an Arduino Mega 2560 microcontroller. The inverse kinematic solution uses geometric and algebraic analytical methods. while the trajectory planning method is using LSPB (Linear Segment Parabolic Blend) Trajectory in Cartesian Space. Data retrieval is done by giving 2 input coordinates of the desired position and orientation, then the data in the form of the joint angle value will be measured using a rotary encoder as an angle sensor. Furthermore, the joint angle measurement value is converted in cartesian coordinates to get the end-effector position. Data analysis is done by comparing the data value of each joint angle with the calculated value so that the error value appears. The results showed that the inverse kinematic and trajectory planning algorithms were successfully applied to the 6-DOF robotic arm to perform straight-flat welding movements. Inverse kinematic testing on both input coordinates, the average error value for joints 2, 3, and 5 is 1.82º, 1.26º, and 2.08º. Meanwhile, the average error of the end-effector position at the x and z coordinates is 2.08 mm and 12.9 mm, respectively. Then for the trajectory planning test, the error value for the end-effector position in the x and z coordinates is 2.25 mm and 10.7 mm.

The increasing progress in the field of satellite navigation systems (GNSS, SBAS) in the recent decades supports effort to use it for determination of train position for railway safety-related systems. Satellite-based augmentation systems (SBAS) such as WAAS in the USA, and EGNOS in Europe, are available and a new global satellite navigation system Galileo is being built by the European GNSS agency (GSA). The currently available SBAS systems were developed in order to satisfy aviation requirements. But the safety concept on railways is very different from the aviation safety concept. The railway safety concept in Europe is determined by means of the CENELEC standards (EN 50126, EN 50129, EN IEC 61508). So it is necessary to find a way how to use GNSS systems in accordance with strict railway standards. The main problem is attainment of sufficient integrity of position solution [5, 12]. Satisfaction of safety integrity level 4 (SIL4) is necessary for railways [6, 7, 8, 9]. At the beginning, it can provide low-cost controlling system for the local, regional and freight railway lines. GNSS provides a 3D position (position in horizontal and vertical plane). The value of altitude is cruical for application in aviation, in ground transportation this value is not so important. On the contrary, the value of horizontal position is cruical. For the purpose of increasing the integrity of GNSS-based position determination we propose a new method of the detection of a GNSS horizontal position error based on the relation between vertical and horizontal position error. As was mentioned for example in [4], as GPS is a three dimensional positioning system, errors between any two coordinates may be correlated, and so there can be relations between errors in individual dimensions. The general 3D GPS-based position solution can be divided into two parts: - 2D horizontal position - 1D vertical position We investigated the relation between errors in the horizontal and vertical plane in real data measured by a GNSS receiver. It was static measurement and the antenna location was exactly known. The vertical position provided by GNSS is not constant. In ground transportation we can mostly make an assumption of nearly a constant value of altitude during the ride. Especially in railway transportation the changing of altitude during the ride is limited by many factors (railway standards, properties of track) So we investigate the possibility of using values of altitude to estimate a position error in the horizontal plane. As the receiver determines the values of the vertical position in real time, the detection of the horizontal position error based on the values of altitude can help detect the actual position error in horizontal plane during the train ride also in real time. The sensitivity of this method to errors in pseudoranges (error caused by multipath) was also investigated. This was done by simulation with software receiver Pegasus (Eurocontrol). The analysis was based on real data from GNSS.