LAUNIS SIRPA (FI)
JULKUNEN PASI (FI)
KASKI MIIKA (FI)
US20160097277A1 | 2016-04-07 | |||
US20160097658A1 | 2016-04-07 |
CLAIMS 1. A method for measuring positions of structural parts of a mining machine, characterized by providing at least one optical fibre in connection with the mining ma- chine for sensing a position of at least one structural part of the mining machine by a beam of light transmitted to the optical fibre and by the optical fibre used as a sensing element; and providing the mining machine with at least one monitoring unit for converting light returning from the at least one optical fibre into at least one measured quantity value describing the position of the structural part, wherein at least one point of the optical fibre is arranged at a known position in relation to the mining machine to provide a reference point for the measurements. 2. A method according to claim 1, characterized in that the at least one optical fibre is used for three-dimensional shape sensing. 3. A method according to claim 1 or 2, characterized by the position comprising at least one of the following: coordinate of the structural part in at least one translational direction, and angle of the structural part in at least one direction of rotation. 4. A method according to claim 3, characterized by the position comprising the coordinates of the structural part in three translational directions and the angle of the structural part in at least one directions of rotation. 5. A method according to any one of the claims 1 to 4, characterize d by arranging a first part of the optical fibre to follow a first known path with a first known position along a first structural part of the mining machine. 6. A method according to claim 5, characterized by arranging a second part of the optical fibre to follow a second known path with a second known position along a second structural part of the mining machine. 7. A method according to claim 6, characterized in that the first known path comprises a straight line arranged in connection with a first structural part of the mining machine, and the second known path comprises a straight line arranged in connec- tion with a second structural part of the mining machine, whereby the determination of position of the first structural part and the second structural part in relation to one another in three translational dimensions and in at least one direction of rotation is enabled. 8. A method according to claim 7, characterized in that at least one angle and/or position of at least one joint of the mining machine is determined on the basis of shape sensing using the at least one optical fibre. 9. A method according to claim 7 or 8, characterized in that at least one angle and/or position of at least two joints of the mining machine is determined on the basis of shape sensing using the same optical fibre. 10. A method according to claim 8 or 9, characterized in that said angle and/or position of the joint is measured and updated at a frequency of at least 50 Hz. 11. A method according to any one of the claims 5 to 10, charac- terized in that the first structural part of the mining machine comprises a carrier of the mining machine, that the second part of the at least one optical fibre comprises the end of the at least one optical fibre opposite to the end connected to the monitoring unit, and that the second known path is arranged in connection with a feed beam of the mining machine to follow a straight line aligned with the direction of a drill rod of the mining machine and at a known position relative to the drill rod, whereby the determination of drilling coordinates in three dimensions and the drill rod angles in two directions of rotation is enabled. 12. A method according to any one of the claims lto 11, character i z e d by providing the at least one optical fibre at least partly within at least one structural part of the mining machine. 13. A method according to any one of claims lto 12, characterize d by providing the at least one optical fibre at least partly on a surface of at least one structural part of the mining machine. 14. A method according to any one of the claims lto 13, character i z e d by retrofitting the at least one optical fibre to an existing mining ma- chine. 15. A method according to any one of the claims 1 to 14, c h a r a c - t e r i z e d in that at a least part of the at least one optical fibre is arranged in connection with hydraulic hoses of the mining machine. 16. An arrangement for measuring positions of structural parts of a mining machine, c h a r a c t e r i z e d in that the arrangement comprises at least one optical fibre in connection with the mining machine for sensing a position of at least one structural part of the mining machine by a beam of light transmitted to the optical fibre and by the optical fibre used as a sensing element; and at least one monitoring unit for converting light returning from the at least one optical fibre into at least one measured quantity value describing the position of the structural part, wherein each optical fibre is connected to the monitoring unit at least at one end of the optical fibre, wherein at least one point of the optical fibre is arranged at a known position in relation to the mining machine to provide a reference point for the measurements. 17. A mining machine comprising an arrangement according to claim 16. |
BACKGROUND
The invention relates to mining machines, and more particularly to a method and arrangement for measuring positions of structural parts of a mining machine.
Different types measurements related to position of structural parts are typically carried out in connection with mining machines. These measurements can be used for instance for controlling the operation of the mining machine and/or for receiving information about the mining machine.
The conventional sensors are typically electrical sensors that convert physical effect on the sensor element into an electrical signal. Electrical sensors require electrical connections, wires and electronics which require mechanical engineering and space and are vulnerable to environmental disturbances. Each measurement signal or measured quantity usually also requires a separate sensor or multiple sensors, which makes the system and the installations complicated.
Typical electronic sensor systems used commonly in mining equipment consist of a power source, a sensor element, a measurement transceiver, I/O cabling, analogue to digital converter and a bus or network cabling. A considerable amount of vulnerable and space consuming electronics and cabling is, thus, needed to get the measured a physical value from the sensor element to be usable by the computing hardware and algorithms. On a system level, for instance hundreds of electrical connections may be required.
BRIEF DESCRIPTION
An object of the present solution is to provide a new method and ar- rangement for measuring positions of structural parts of a mining machine. The objects of the solution are achieved by a method and an arrangement, which are characterized by what is stated in the independent claims. Some embodiments of the invention are disclosed in the dependent claims.
The solution is based on the idea of providing a mining machine with at least one optical fibre and at least one monitoring unit, and using the optical fibre itself as a sensing element to measure positions of structural parts of a mining machine. Thus, a need for electrical connections arranged on the mining machine is eliminated or at least decreased considerably. In addition, the optical fibre based sensing is naturally flameproof, which is beneficial in many applica- tions and required for required for instance in coal mining. As added electrical connections and separate conventional sensor elements are no longer needed, a larger number of measurements can be made in a manner that is simpler and more robust in harsh environments.
Some other advantages of the solution are discussed in connection with the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which
Figure 1 illustrates an example of a mining machine and an arrangement in the mining machine;
Figure 2 illustrates schematically an arrangement in connection with a mining machine;
Figure 3 illustrates schematically a method for measuring positions of structural parts of a mining machine;
Figure 4 illustrates schematically another method for measuring positions of structural parts of a mining machine;
Figures 5a and 5b illustrate schematically a detail of an arrangement in connection with a mining machine in different positions of structural parts of the mining machine;
Figures 6a and 6b illustrate schematically the details of Figures 5a and 5b, respectively, from the measurement point of view;
Figures 7a and 7b illustrate schematically the details of Figures 5a and 5b, respectively, from the vector point of view;
Figure 8 illustrates schematically an embodiment of a control system for an arrangement for measuring positions of structural parts of a mining machine; and
Figures 9a, 9b, 9c and 9d illustrate schematically cross sections of optical fibres according to different embodiments. DETAILED DESCRIPTION OF THE INVENTION
Different types of mining machines are known in the art and it is clear for a person skilled in the art that the figures are provided for illustrative purposes only and the solutions described in this description are applicable also for mining machines with different configurations and structure. The mining machine 1 may, thus, comprise for instance at least one of the following: a rock drilling rig, a crusher, a continuous mining machine, a loader, and a dump truck.
Figure 1 illustrates an example of a mining machine 1 and an arrangement for measuring positions of structural parts of the mining machine 1 and Figure 2 illustrates schematically an arrangement for measuring positions of structural parts of a mining machine 1 schematically. In the embodiment of Figure 1, the mining machine 1 comprises a mobile rock drilling rig comprising a movable carrier 2 provided with several wheels 3, a driver cabin 4 and booms 5. These are also some examples of structural parts of a mining machine 1, but a mining machine may also comprise numerous other types of structural parts, such as ac- tuators, joints, boom sections arranged pivotally to one another, tools and so on. The mining machine 1 is further provided with a control system which includes at least a first control unit (not shown) configured to control actuators in the mining machine 1 for controlling and driving the machine. However, the mining machine may, thus, comprise a different type of a mining machine instead of a rock drilling rig.
The arrangement for measuring positions of structural parts 8 of a mining machine 1 may comprise at least one optical fibre 6 provided in connection with the mining machine 1 for sensing a position of at least one structural part of the mining machine 1 by a beam of light transmitted to the optical fibre 6. The optical fibre 6 may, thus, be used as a sensing element. The arrangement for measuring positions of structural parts 8 of a mining machine 1 may also comprise at least one monitoring unit 7 for converting light returning from the at least one optical fibre 6 into at least one measured quantity value describing the position of the structural part 8, wherein each optical fibre 6 is connected to the moni- toring unit 7 at least at one end of the optical fibre. In different embodiments, the monitoring unit may be arranged fixedly or removably in connection with the mining machine 1. According to an embodiment, the monitoring unit 7 may comprise a fibre interrogator. According to a further embodiment, another controller, such as a control unit of the mining machine, may be used to further process the data provided by the optical fibre 6 and the monitoring unit 7 for use for monitoring and controlling of a mining machine or for some other purpose. At least one point of the optical fibre 6 may be arranged at a known position in relation to the mining machine 1 to provide a reference point for the measurements. In other words, this known position of the optical fibre 6 and the corresponding known position of the mining machine 1 that the known position of the optical fibre 6 is arranged to provides the reference point for the measurements, that is the point which all the other positions data of the optical fibre(s) 6 and the corresponding points of the mining machine 1 they are arranged to are compared with. An embodiment of a control system is illustrated schematically in connection with Figure 8.
Figure 3 illustrates schematically a method for measuring positions of structural parts of a mining machine. Such a method may be executed by a mining machine 1 and/or an arrangement such as described in this description. The method may comprise providing 31 at least one optical fibre in connection with the mining machine for sensing a position of at least one structural part of the mining machine by a beam of light transmitted to the optical fibre. The optical fibre 6 may, thus, be used as a sensing element in the method. The method may also comprise providing 32 the mining machine with at least one monitoring unit 7 for converting light returning from the at least one optical fibre 6 into at least one measured quantity value describing the position of the structural part 8. In other words, the light backscattered from the optical fibre 6 may be analysed and the position of the structural part may be determined based on the analysis results converted into the measured quantity value (s). In the method, at least one point of the optical fibre 6 may be arranged 33 at a known position in relation to the mining machine to provide a reference point 9 for the measurements. Accord- ing to an embodiment, the converting light returning from the at least one optical fibre 6 into at least one measured quantity value describing the position of the structural part 8 may comprise analysing the backscattered light from the optical fibre 6 to determine the position of the structural part. It is clear for a person skilled in the art that the light returning from the at least one optical fibre 6 may also be converted into at least one measured quantity value in any other manner known as such in connection with optical fibres.
Figure 4 illustrates schematically another method for measuring positions of structural parts of a mining machine. This method may comprise sensing 41 a position of at least one structural part 8 of the mining machine 1 by a beam of light transmitted to at least one optical fibre 6 provided in connection with the mining machine 1. The optical fibre 6 may, thus, be used as a sensing element. The method may further comprise converting 42 light returning from the at least one optical fibre 6 by at least one monitoring unit provided in connection with the mining machine into at least one measured quantity value describing the position of the structural part 8. The method may further comprise arranging 43 at least one point of the optical fibre 6 at a known position in relation to the mining ma- chine 1 to provide a reference point 9 for the measurements. According to an embodiment, method for measuring positions of structural parts of a mining machine may be used for measuring position of a boom joint, a relative position of boom arms or a position of a boom part in relation to the movable carrier 2, for example. Thereby, many conventional sensors, such as resolvers for axial sensing, can be replaced by one optical fibre 6.
Figures 9a, 9b, 9c and 9d illustrate schematically cross sections of optical fibres according to different embodiments. These embodiments comprise at least one optical fibre core 6a and a protective layer 6b surrounding the optical fibre core 6a. The optical fibre cores and the protective layer are not shown to scale but to illustrate the principle only. Figure 9a illustrates an embodiment, wherein a single cable comprises an optical fibre core 6a and a protective layer 6b surrounding the optical fibre core 6a.
According to an embodiment, the optical fibre 6 may comprise at least one fibre core 6a and a protective layer 6b surrounding the fibre core. Such embodiments are illustrated in Figures 9c and 9d. According to an embodiment, the optical fibre 6 may comprise at least three optical fibre cores 6a provided together as a single cable with a common protective layer 6b. According to a further embodiment, the optical fibre 6 may comprise at least three optical fibre cores 6a provided together as a single cable with a common protective layer 6b and with a 120 degree alignment between the optical fibres within the cable. An example of such an embodiment is shown in Figure 9c. According to another embodiment, the optical fibre 6 may comprise at least three optical fibre cores provided as separate cables with separate protective layers and arranged fixedly to one another. According to a further embodiment, the optical fibre 6 may comprise three optical fibre cores provided as separate cables with separate protective layers and arranged fixedly to one another with a 120 degree alignment between the optical fibres. An example of such an embodiment is shown in Figure 9b. These embodiments enable more advanced measuring possibilities, such as 3D shape sensing. According to an embodiment, the optical fibre 6 may comprise four or more optical fibre cores provided as a bundle comprising a common protective layer and/or separate protective layers. This may enable even more advanced, complex and accurate measurements to be made. In such embodiments, each optical fibre core 6a or each cable comprising optical fibre core(s) and protective layer (s) may be considered as an optical fibre 6 in the sense of the other embodiments described in this description. According to an embodiment, the protective layer comprises a shock absorbing rubber material.
According to an embodiment, the optical fibre 6 may comprise one or several cores provided within a band or matt-like protective layer. An example of such an embodiment is shown in Figure 9d. According to an embodiment, the op- tical fibre band or matt may comprise a length within a range of 1 meter to 3 meters long , a width within the range of 2 centimeters to 8 centimeters wide and a thickness within a range of 0.5 centimeters to 2 centimeters. Such a band or matt may be particularly useful for instance for measuring joint angles and displacements of structural parts in relation to one another. The band or matt shaped pro- tective layer can make the optical fibre more robust to prevent over bending of the fibre, for example. It is also easy to attach to a surface of a structural part for instance by gluing and it can be used without any additional mechanics or electrics.
According to an embodiment, the at least one optical fibre 6 may used for three-dimensional shape sensing.
According to an embodiment, the position may comprise at least one of the following: coordinate of the structural part in at least one translational direction, and angle of the structural part in at least one direction of rotation. According to other embodiments, the position may comprise the coordinates of the structural part in three translational directions and the angle of the structural part in at least one or in at least two directions of rotation. The translational directions refer to the so called x-axis, y-axis and z-axis, where each one of the directions is transverse with respect to the other directions. The directions of rotation refer to the directions of rotation about each one of the translational direc- tions, respectively, or about some other actual axis of the mining machine or a theoretical/calculatory rotational axis. In other words, each direction of rotations refers to rotation about one of the translational directions or axis. Thus, the direction of rotation does not refer here to whether the rotation is clockwise or counter clockwise with respect to the translational direction or axis. In the embodi- ment described above, the position may thus comprise for instance coordinates of the structural part 8 in at least two of these three directions of rotation.
Figures 5a and 5b illustrate schematically a detail of an arrangement in connection with a mining machine in different positions of structural parts of the mining machine. Figures 6a and 6b illustrate schematically the details of Figures 5a and 5b, respectively, from the measurement point of view. Figures 7a and 7b illustrate schematically the details of Figures 5a and 5b, respectively, from the vector point of view.
According to an embodiment, a first part of the optical fibre 6 may be arranged to follow a first known path 10a with a first known position along a first structural part 8a of the mining machine 1. In other words, in this embodiment the first part of the optical fibre may be arranged to the first structural part 8a in such a manner that it follows a first known path 10a the position of which first known path 10a with respect to the dimensions of the first structural part 8a is known. According to an embodiment, the first known path 10a comprises at least two points 11a, lib, 11c along the first part of the optical fibre 6 and the first known position along the first structural part 8a comprises a corresponding number of points of the first structural part 8a the position of which with respect to the dimensions of the first structural part 8a is known, and each point of the first known path 10a along the first part of the optical fibre 6 is arranged on one of the points of the first known position along the first structural part 8a, respec- tively. Thereby, the first known path 10a of the first part of the optical fibre 6 and the position on the first structural part 8a it is arranged on is known.
According to another embodiment, a second part of the optical fibre 6 is arranged correspondingly to follow a second known path 10b with a second known position along a second structural part 8b of the mining machine 1. Ac- cording to an embodiment, the second known path 10b may comprise at least two second points 12a, 12b, 12c along the second part of the optical fibre 6 and the second known position along the second structural part 8b comprises a corresponding number of points of the second structural part 8b the position of which with respect to the dimensions of the second structural part 8b is known, and each point of the second known path 10b along the second part of the optical fibre 6 is arranged on one of the points of the second known position along the second structural part 8b, respectively. Thereby, the second known path 10b of the second part of the optical fibre 6 and the position on the second structural part 8b it is arranged on is known.
According to an embodiment the first known part 10a, the second known part 10b and the corresponding first and second points along the optical fibre 6 may be arranged on one and same structural part 8. This may be beneficial for instance in connection with flexible structural parts, whereby the same structural part 8 may comprise both the first structural part 8a and the second struc- tural part 8b in the sense of the arrangement for measuring positions of structural parts of a mining machine described in this description. According to a further embodiment, the first known path 10a may comprise a straight line arranged in connection with a first structural part 8a of the mining machine 1, and the second known path 10b may comprise a straight line arranged in connection with a second structural part 8b of the mining ma- chine 1, whereby the determination of position of the first structural part 8a and the second structural part 8b in relation to one another in three translational dimensions and in at least one direction of rotation is enabled. According to an embodiment, such a combination of a first known path 10a and a second known path 10b as described above may thus be used for determining for instance a joint an- gle and/or a distance between the first structural part 8a and the second structural part 8b or a point thereof with respect to one another. According to another embodiment, the determination of position of the first structural part 8a and the second structural part 8b in relation to one another in three translational dimensions and in at least two directions of rotation is enabled.
According to an embodiment, at least one angle and/or position of at least one joint 13a, 13b of the mining machine 1 may be determined on the basis of shape sensing using the at least one optical fibre 6.
According to an embodiment, at least one angle and/or position of at least two joints 13a, 13b of the mining machine may be determined on the basis of shape sensing using the same optical fibre 6. This reduces considerably the need for separate sensing elements of the conventional type and the electrical wiring they typically require.
According to an embodiment, the angle and/or position of the joint may be measured and updated at a frequency of at least 50 Hz. This provides sub- stantially continuous measurement of the position and enables using the data for example for controlling the mining machine 1.
Figures 5a and 5b illustrate schematically a detail of an arrangement in connection with a mining machine 1. In Figure 5a a first structural part 8a and a second structural part 8b are in a position where they are not rotated in relation to one another, in other words in a neutral position in relation to one another. In Figure 5b the second structural part 8b is rotated about an axis J2 of a first joint 13a by an angle A. Figures 6a and 6b illustrate the same positions of the first structural part 8a and the second structural part 8b from the measurement point of view and as vectors in Figures 7a and 7b. Although in Figures 5b, 6b and 7b the second structural part 8b is only rotated about the axis J2, a similar arrangement could be used for measuring the rotation about the axis Jl of the second joint 13b and or about both axis Jl and axis J2 as well. For illustrative purposes, the joints 13a, 13b are illustrated by a combination of a cylinder and a plane to better show the rotation in the three-dimensional coordinate system. Similarly, the first structural part 8a and the second structural part 8b are illustrated by simple lines.
According to an embodiment, the first structural part 8a of the mining machine may comprise a carrier 2 of the mining machine 1, the second part of the at least one optical fibre 6 may comprise the end of the at least one optical fibre 6 opposite to the end connected to the monitoring unit 7, and the second known path 10b may be arranged in connection with a feed beam of the mining machine 1 to follow a straight line aligned with the direction of a drill rod of the mining machine 1 and at a known position relative to the drill rod. In other words, the second structural part 8b of the mining machine 1 may comprise a feed beam. Thereby the determination of drilling coordinates in three dimensions and the drill rod angles in two directions of rotation may be enabled.
Figure 8 illustrates schematically an embodiment of a control system for an arrangement for measuring positions of structural parts of a mining machine 1. This is only an example of a control system that may be used for measuring positions of structural parts of the mining machine and for executing the methods described in this description and utilizing the arrangements described in this description for controlling, measuring and/or monitoring of the mining machine. The control system may comprise graphical user interfaces (GUI1, GUI2) provided in connection with the mining machine 1 for user interaction and for visualizing the measured quantities, for example, for the end user; interfaces to external networks, data transfer in and out and for remote user interfaces (Re- mote); controllers such as a master controller for mining machine level control and diagnostics, and other controllers for power, boom(s), carrier, valve(s) and controllers for other components and operations related to the mining machine; monitoring unit(s) (Optic interrogator) and/or optical fibres 6. The control system may also comprise valves (V) for instance for controlling tools, actuators and operations of the mining machine 1. According to an embodiment, the control system may comprise conventional sensors as well.
According to an embodiment, the at least one optical fibre 6 may be provided at least partly within at least one structural part 8, 8a, 8b of the mining machine 1. According to an embodiment, the at least one optical fibre 6 may be provided at least partly on a surface of at least one structural part 8, 8a, 8b of the mining machine 1 instead of or in additional to being provided partly within a structural part 8, 8a, 8b.
According to an embodiment, the at least one optical fibre 6 is retrofitted to an existing mining machine 1.
According to an embodiment, at a least part of the at least one optical fibre 6 may be arranged in connection with hydraulic hoses of the mining machine 1.
According to an aspect, a mining machine 1 may comprise an arrangement described above. The mining machine 1 may, thus, comprise for instance at least one of the following: a rock drilling rig, a crusher, a continuous mining machine, a loader, and a dump truck.
It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
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