Boom-type Roadheader Research Articles

Infrared LEDs-Based Pose Estimation With Underground Camera Model for Boom-Type Roadheader in Coal Mining

Accurate and reliable pose estimation of a boom-type roadheader is of great importance in order to maintain the efficiency of automatic coal mining. The stability and accuracy of conventional measurement methods are difficult to be guaranteed on account of vibration noise, magnetic disturbance, electrostatic interference, and other factors in an underground environment. In this paper, a vision-based non-contact measurement method for cutting-head pose estimation is presented, which deploy a 16-point infrared LED target on the boom-type roadheader to tackle the low-illumination, high-dust, and complicated background. By establishing a monocular vision measurement system, the cutting-head pose is estimated through processing the LED target images obtained from an explosion-proof industrial camera mounted on the roadheader. After analyzing the measurement mechanism, an underground camera model based on the equivalent focal length is built to eliminate refraction errors caused by the two-layer glasses for explosion-proof and dust removal. Then, the pose estimation processes, including infrared LEDs feature point extraction, spot center location, and an improved P4P method based on dual quaternions, are carried out. The influence factors of cutting-head pose estimation accuracy are further studied by modeling, and the error distribution of the main parameters is investigated and evaluated. The numerical simulation and experimental evaluation are designed to verify the performance of the proposed method. The results show that the pose estimation error is in line with the numerical prediction, achieving the requirements of cutting-head pose estimation in underground roadway construction in the coal mine.

Studies of behaviour of the automatic control system of roadheader cutting heads movement

Boom–type roadheaders are basic machines used in underground mines for drilling roadways, in tunnelling and also for making underground buildings using trenchless methods. The article presents selected results of tests carried out in a semi–industrial scale, on a roadheader R–130, concerning behaviour of an innovative solution of system for automatic control of boom–type roadheader cutting heads’ movements. This important innovation, not known before in mining cutting machines, is the software control of cutting heads angular speed using a frequency converter. The text shows an impact of key values, from a perspective of an assumed control purpose, of programming device (setting system) parameters, achieving reference values for the actuators, on controlled facility behaviour when cutting a layered cement and sand block. The performance of the automatic control system without and with feedback to the setting system concerning an actual speed of cutting heads movement, which is important from the control system hardware perspective, was compared.

Ultra-wideband pose detection method based on TDOA positioning model for boom-type roadheader

In deep and dangerous coal seam tunnelling, the autonomous navigation control system (ANCS) of the boom-type roadheader is the core that realises unattended work. The remote pose detection of the boom-type roadheader is the key task of the ANCS. In this study, an ultra-wide band (UWB) pose detection system (UPDS) for boom-type roadheaders is designed which realises the remote measurement of position and attitude parameters (heading, roll, and pitch angles) of the boom-type roadheader in a narrow and long enclosed roadway space. Based on the time difference-of-arrival (TDOA) positioning model, three UPDS positioning algorithms are proposed: Indirect positioning algorithm (IPA-D), Taylor series expansion algorithm (Taylor-D), and Chan positioning algorithm (Chan-D). A complete calculation process is deduced from the three UDPS positioning algorithms. Their accuracies are analysed based on the measured data of a P440 UWB ranging module in a narrow and long roadway. The positioning accuracy of IPA-D behaves better than those of Taylor-D and Chan-D: Within 95 m of the roadway, IPA-D can achieve values at a centimetre scale and the positioning error increases with increasing measurement distance. The calculated UPDS attitude angle error based on IPA-D increases with increasing measurement distance of up to 95 m; The roll angle error is approximately 0.05°, and the pitch and heading angles are approximately 0.15°. The presented UPDS meets the accuracy requirements for the pose detection of boom-type roadheaders in a fully mechanised excavation face and provides a reliable theoretical basis for ANCSs of boom-type roadheaders.

Dust removal of large cross-section tunnels: following ventilation and its adjustment strategy

Concerning human health and safety, more studies should be taken place on the impact of dust movement in the tunnels construction. In the case of large cross-section tunnels driven by boom-type roadheader, dust removal efficiency of the ventilation system is essential for safety protection in tunnels. For the first time, to adapt the larger cross-section tunnels, the following ventilation system has been proposed, and the feasibility has been proven by the comparison results of CFD numerical simulation between large and small cross-section tunnels. Comparisons of removal effect for different cutting point have been made, and the adjustment direction to better removal effect has been summed up. In addition, the two adjustment strategies have been presented and compared within actual working conditions. The results indicated the best parameters range of following ventilation system refers to distance and airflow ratio. The data about dust concentration on different height plane are meaningful for further study into dust removal in large cross-section tunnels, and the rules could be applied in other larger cross-section tunnels.

Kinematic models and simulations for trajectory planning in the cutting of Spatially-Arbitrary crosssections by a robotic roadheader

In this study, a boom-type roadheader’s mechanical composition was simplified into a kinematic chain composed of a series of linked translational or rotational joints, and a coordinate system was constructed for the spatial pose of the roadheaders. Homogeneous coordinate transformations and robot kinematics were used to construct a spatial pose matrix for the pose of a roadheader’s body and cutting head relative to the geodetic coordinate system. The compressive breaking forces of a cutting head during vertical and rotary cutting of coal walls was analyzed, and the trajectory planning for the cutting of arbitrary crosssections was described in detail. In addition, simulations of the limits of a roadheader in the cutting of crosssections were performed. Underground roadheader cutting trajectories were measured via the pose measurement sensors installed on the roadheader to verify the accuracy of the mathematical modeling, and it was determined that cuttings performed using manually-operated levers were highly random and had lower levels of crosssection forming quality. Therefore, trajectory planning and simulations for actual coal mine roadways as well as field tests on an S-shaped bottom-up trajectory plan for automated cutting were performed. The results of these tests indicated that the maximum absolute error on both sides of a coal roadway that has a 4500 × 4000 mm crosssection was 65 mm, which corresponds to a maximum relative control error of 1.4%. Hence, the control system developed in this work was observed to exhibit accuracy and quality that satisfy requirements for cross sections in a coalmine’s roadways, effective repeatability, and absence of cumulative deviations. Hence, the results of this research study are highly significant and are of value for practical applications.

Multifactor Analysis of Roadheader’s Body Pose Responses during the Horizontal Cutting Process

Based on the Lagrange equation in system dynamics, aiming at the horizontal cutting process, the dynamical coupling model of boom‐type roadheader’s body pose was established. According to input problem of solving the model, a calculation method of the cutting head load was proposed, and the relationship between the cutting head load and pressure of the driving cylinders and swing angle of the cutting arm was obtained through simulating analysis. The simulation model was established to solve the dynamical coupling model. The cutting head load, horizontal swing angle of the cutting arm, and dip angle of coal seam were regarded as independent variables to perform changing parameter analysis in variations of the body pose. The field experiment was carried out, and the measured data is basically consistent with the simulation values. The results show that lateral displacement of the body can reach up to 6.5 cm, backward displacement can reach up to 5.2 cm, floor‐based quantity can reach up to 11 cm, pitch angle of the body can reach up to 7.8°, and roll angle can reach up to 2.1°. Variations of the body pose parameters are influenced greatly by the cutting head load, while the influence from horizontal swing angle of the cutting arm and dip angle of coal seam is slighter. Among the pose parameters, floor‐based quantity and pitch angle of the body vary relatively greatly, which tend to seriously influence forming quality of the roadway and should be mainly considered in deviation rectification of the roadheader’s body pose.

Ultra-wideband pose detection system for boom-type roadheader based on Caffery transform and Taylor series expansion

To realize unmanned pose detection of a coalmine boom-type roadheader, an ultra-wideband (UWB) pose detection system (UPDS) for a roadheader is designed, which consists of four UWB positioning base stations and three roadheader positioning nodes. The positioning base stations are used in turn to locate the positioning nodes of the roadheader fuselage. Using 12 sets of distance measurement information, a time-of-arrival (TOA) positioning model is established to calculate the 3D coordinates of three positioning nodes of the roadheader fuselage, and the three attitude angles (heading, pitch, and roll angles) of the roadheader fuselage are solved. A range accuracy experiment of a UWB P440 module was carried out in a narrow and closed tunnel, and the experiment data show that the mean error and standard deviation of the module can reach below 2 cm. Based on the TOA positioning model of the UPDS, we propose a fusion-positioning algorithm based on a Caffery transform and Taylor series expansion (CTFPA). We derived the complete calculation process, designed a flowchart, and carried out a simulation of CTFPA in MATLAB, comparing 1000 simulated positioning nodes of CTFPA and the Caffery positioning algorithm (CPA) for a 95 m long tunnel. The positioning error field of the tunnel was established, and the influence of the spatial variation on the positioning accuracy of CPA and CTFPA was analysed. The simulation results show that, compared with CPA, the positioning accuracy of CTFPA is clearly improved, and the accuracy of each axis can reach more than 5 mm. The accuracy of the X-axis is higher than that of the Y- and Z-axes. In section X-Y of the tunnel, the root mean square error (RMSE) contours of CTFPA are clear and orderly, and with an increase in the measuring distance, RMSE increases linearly. In section X-Z, the RMSE contours are concentric circles, and the variation ratio is nonlinear.

Position and Attitude Measurement System Design of Boom-type Roadheader

In deep coal seam, high rock-burst and frequent geological disasters lead to high danger coefficient, so research of unmanned mining technology is extremely important. Autonomous position and attitude measurement technology of boom-type roadheader is a core part of unmanned mining technology, which has great research significance. In the boom-type roadheader position and attitude measurement system of this paper, the laser transmitter is equipped on boom-type roadheader to transmit fan-shaped laser beam, and the laser receiver is fixedly set in the rear of the laser transmitter. Bases on principle of angle measurement by the fan-shaped laser beam, the position and attitude parameters of boom-type roadheader is measured and calculated. This system is able to achieve autonomous and high-precision measurement of the position and attitude. In this paper, laser-based positioning technology is improved, and the fundamental principle of position and attitude measurement is established. Based on that, the position and attitude measurement system is designed, and the hardware architecture of the fan-shaped laser beam transmitter and receiver is designed and selected. Boom-type roadheader position and attitude measurement system in this paper changes the traditional mode of roadway excavation and lays foundation for unmanned mining in deep dangerous coal seam.

Visual measurement system for roadheaders pose detection in mines

To satisfy the demand for automatic roadway drivage in mines, a real-time body pose detection system is proposed for the mine-used boom-type roadheader. Utilizing cross lasers and laser targets as information sources, this system first establishes a mathematical model to describe the machine position in space and realizes the precise localization of reference points on targets via the improved Retinex adaptive image enhancement algorithm and maximum wavelet transform module algorithm. It then sets up the machine body position calculating model and makes use of the space matrix transformation method to obtain the yaw, pitch, roll angles, and horizontal and vertical deviations of the roadheader, finally fulfilling the automatic machine pose detection in real time. Based on the preceding theoretical analysis, an experimental platform is built up in laboratory conditions for the purpose of simulating pose changes of the machine inside the tunnel and automatically detecting its position. The experimental results show that the measurement accuracy of angles is within 0.16 deg and the detection precision of displacements is higher than 10 mm, which can satisfy requirements of automatic, precise, and real-time positioning for the roadheader during the process of tunnel construction.

Effects of Spiral Line for Pick Arrangement on Boom Type Roadheader Cutting Load

Effects of Spiral Line for Pick Arrangement on Boom Type Roadheader Cutting Load

Application of Approximate Iterative Method on Section Precision Forming of Boom-type Roadheader

The decision of the inflection point is the key to ensure automatic section cutting precision using a boom-type road header. In this paper, cutting precision model was set up for the first time to trapezoidal section and a method deter- mining inflection point is given. Considered the cutting head' projection at section is elliptical with the cantilever's joint variable. The relationship between ellipse curve and cutting section boundary was investigated, and thereby sets up the cutting precision model. Approximate iterative method is used to finding the optimal inflection point, of which takes the cutting precision as the objective function. Compared with the traditional process path planning method, the forming ac- curacy can be improved greatly and controlled within 1mm. Through MATLAB simulation, it is proved that this method is correct and valid.

Design of Transverse Boom-Type Roadheader Remote Control System

The roadheader remote control system is proposed to protect operator away from the dust and the danger on working site, improve the operator's labor environment, reduce personal injury accidents, and enhance the security of mining operations. The cutting head and spade board position of transverse boom-type roadheader were analyzed. The mathematical models of cutting head vertical swing, cutting head gyration swing and spade board vertical swing were established. Geometric relationship between the angle and the stroke of hydraulic cylinder of cutting head and spade board were calculated. Finally, based on programmable logic controller (PLC) and industrial personal computer (IPC), the remote control system was designed and the automatic cutting method was proposed. The roadheader remote control system had been applied successfully in EBH132 roadheader. The system significantly enhances the efficiency and security of the main production.

Design and Application on Multi-Function Construction Platform of Boom Type Road-Header

When the frame shield support was applied in the fully mechanized driving process of the seam gateway, there would be some incongruous problems. Aimed at the problems, mainly was discordance between the fully mechanized driving and the gateway support, we put forward the requirements of the multi-function platform and made the design scheme clear. By applying the finite element software, the simulation of the dynamics response was conducted on the multi-function platform. On this basis, an analysis was conducted on the stress of each loading part, the simulation results and mechanics calculations have shown the design of the multifunction platform could fully meet each technical index. The on-site applications have revealed that the platforms match with the fully mechanized driving machinery rationally; provide a safety standing basis for the construction of the frame shield support. Further, the platform has improved the mechanization of the frame shield support and increased the support operation efficiency.

Study on the Shovel and Support Bracket’s Compensation for Vertical Pose’s Deviation of Roadheader

Automatic directional excavation technology in the coal mine laneway is the important research direction of integrated excavation project. Shovel and support bracket are the most key parts for keeping roadheader body stable in excavation. This paper studies the control ability and extreme position of boom-type roadheader’s shovel and support bracket, to calculate the adjustable vertical angles rang which is realized by shovel and support bracket, expanding roadheader’s automatic compensating excavation ability, meanwhile ensuring body stable. Vertical angle is one of the four kinds of basic body pose deviation parameters. This study is the research basis for the accuracy analysis of boom-type roadheader’s directional excavation. Because the depth that shovel and support brackets’ tip compress into laneway ground, is mainly determined by laneway ground hardness and body weight, and can’t be calculate accurately, paper’s end gives feedback control application of shovel and support bracket according to laneway conditions.

Study on the Section's Extreme Position of Roadheader's Cutting Arm in Coal Mine Laneway

Directional excavation technology in the coal mine laneway is the important research direction of integrated excavation project. This paper studies the changes of cutting section shape and boundary values caused by the swing of boom-type roadheader's cutting arm ​​to calculate the maximum values of compensable pose deviation when cutting, as the research basis for the accuracy analysis of boom-type roadheader's directional excavation. This paper gives the calculation method of cutting arm control, spatial modeling and analysis of cutting head position changes caused by cutting arm in thought of the three-dimensional analytic geometry, and also gives verification in the way of Matlab graphics simulation. At last, a control method to compensate section boundary by cutting arm is put forward.

Analysis of Dynamic Characteristics of Rotary Mechanism for Boom Type Roadheader

A solid model of rotary mechanism for boom type roadheader was built by means of UG software. The solid model was introduced into the ADAMS through the interface of the UG solid model and the ADAMS and a simulation model of machinery-hydraulic coupling system of boom type roadheader was established. Dynamics simulation was carried out. Force curves of the rotary cylinder and the lift cylinder to the rotary table joints under different positions were obtained. The relationship between the axial force and radial force in the same period was analyzed. Research results could improve the stability of boom type roadheader working process and provide a strong theoretical basis for the further optimal design of the rotary mechanism.

Application and testing of a vertical angle control for a boom-type road header

Automatic profiling control using a boom-type roadheader requires an understanding of horizontal and vertical swing angles of the cutting boom. In this study the vertical angle of the cutting boom is discussed. First, a vertical swing detection model for the cutting boom is established. Then, a kinematic analysis of the vertical swing mechanism is made and formulae describing the geometrical relationship between the vertical swing of the cutting boom and the telescopic length of vertical hydraulic lift cylinders and vertical swing angle of the boom are presented. Various factors such as complexity of the calculation model, the difficulty of installing the sensor and the cost are compared for two methods. Finally, directly measuring the vertical swing angle of the cutting boom with a tilt sensor is decided to be the more simple and effective method. The detection sensitivity and the vertical cutting error of a tilt sensor are studied. Vibration tests on an EBZ160 roadheader were performed in a coal mine. The characteristic vibration frequencies are analyzed. A design of a vibration isolation mount for the tilt sensor is presented. It makes the detection device work more reliably under conditions where vibration is present and lays a foundation for the implementation of an automatic roadhead cutter. A tilt sensor is installed on an EBZ160 and an EBZ200, and experiments have been done in a coal mine. The results show that the experimental result is favorable and achieves the goal of automatic control of the vertical swing of the cutting boom.

Effects of circumferential pick spacing on boom type roadheader cutting head performance

Abstract Effects of equal and unequal circumferential pick spacing on the performance of boom type roadheaders having cylindrical cutting heads are investigated. For this purpose, two experimental cutting heads with equal and unequal circumferential spacing are designed and manufactured. The cutting head with unequal circumferential spacing is specifically designed to prevent tool-holder overlap at the nose section. Manufacturing difficulties associated with equal circumferential pick spacing due to tool-holder overlap are discussed with solid modeling and practical applications. The heads are tested at Park Cayirhan Coal Mine in Turkey and their cutting performances are analysed. Although better cutting performance for equal circumferential spacing are predicted by force–balance analysis, in situ measurements of instantaneous (net) traversing speed and cutting rate, pick consumption rate and machine vibration show that no significant difference exists between the performances of the two cutting heads.

Drivages in abrasive rock with the WAV 300 boom-type roadheader (In German and English) : Zilligen K.H. GluckaufV121, N19, 10 Oct 1985, P1466–1472 (german), P448–451 (english) (paper to the Shaft Sinking and Tunnelling Colloquium, Berlin, 21–22 Feb 1985)

Drivages in abrasive rock with the WAV 300 boom-type roadheader (In German and English) : Zilligen K.H. GluckaufV121, N19, 10 Oct 1985, P1466–1472 (german), P448–451 (english) (paper to the Shaft Sinking and Tunnelling Colloquium, Berlin, 21–22 Feb 1985)

Development of a water jet system to improve the performance of a boom type roadheader : Plumpton, N A; Tomlin, M G in: Sixth International Symposium on Jet Cutting Technology, University of Surrey, 6–8 April 1982, p267–282. Publ Cranfield: BHRA, 1982

Development of a water jet system to improve the performance of a boom type roadheader : Plumpton, N A; Tomlin, M G in: Sixth International Symposium on Jet Cutting Technology, University of Surrey, 6–8 April 1982, p267–282. Publ Cranfield: BHRA, 1982