GB2507269A - Determining the spatial relationship between two surfaces - Google Patents

Abstract

A positional offset measurement system is provided for determining the spatial relationship between two surfaces. The surfaces may be a first surface 14 of a pipe 16 and a second surface 24 of a pipe 26. A first end assembly 12 is associated with first surface 14, and a second end assembly 22 is associated with second surface 24, wherein each end assembly is provided with at least two communication modules 20a to 20d;30a to 30d, such that signals transmitted between the first and second end assemblies by the communications modules can be used to determine the relative position of the first and second surfaces. Data signals are sent to associated data processors 11 and 21 on the end assemblies for processing.

Description

APPARATUS AND METHOD FOR DETERMINING A SPATIAL RELATIONSHIP

BETWEEN TWO SURFACES

The present invention relates to a measuring system and, in particular, a measuring system for determining the position and orientation of two surfaces with respect to each another.

The measurement of a volume or space occupied by a physical body is not a new concept.

However, in many applications, there is a requirement to be able to determine the relative position and orientation of objects with respect to each other.

An example of such an application is the position and orientation of two pipe end sections, between which a custom manufactured dosing spool is required to be installed. The dimensions of the closing spool relate direcdy to the position and the orientation of the respective flanges on the end of the pipe sections.

Originally, such closing spools were manufactured through a process of trial and error. Such a method is time consuming and requires a highly skilled individua' to cariy out the work. In addition, there is a tendency to force a poorly fitting closing spool into the space between the two pipe end sections. Forcing a poorly fitting closing spool to connect two pipe end sections results in undue stress and strain being applied to the associated pipes thus increasing the likelihood of fracturing and hence leaks.

There are a number of prior art documents that teach of measurement systems based on the employment of theodolites. An alternative prior art solution to this problem is a measurement system based on a gimbal assembly, as taugh in US Patent No. 4,120,095 (Lebourg). In this arrangement, the position and orientation of relevant surfaces are measured as a set of horizontal and vertical angles with respect to a single point, ongin or horizon at some distance from the surfaces. However, the need for a reference point or horizon acts to limit the use of such systems.

Another alternative solution presented in the prior art is a measurement system based on a linear transducer and incfinometer that are empthyed to define a common axis between the two surfaces. Angular transducers are then employed to measure the orientation of each surface with respect to the commonly defined axis. Additional measurement systems such as theodolites and aser systems involve considerable set-up times and a significant amount of post measurement processing of the captured data. Therefore, such systems are known to be cumbersome and require additional support in order to maintain the device in position while the required readings are taken. Such characteristics are an obvious disadvantage when the measurement system is required to be deployed at remote locations.

A further alternative solution presented in the prior art is a measurement system which provides end cap flanges which are connected by a positional offset measurement instrument comprising a flexible arm which can be manipulated within an defined volume of space such that the end cap flanges are brought into co-operation with the end surfaces of the two pipes.

However, whilst this provides an actual physically defined representation of the requirements of the connector spool for connecting the two pipe ends, the adjustment and accurate placement of the flexible arm and end cap flanges is a labour intensive process which must result in the accurate placement of the end caps to ensure and accurate representation of the required connector.

An object of at least one aspect of the present invention is to obviate or mitigate one or more of the aforementioned disadvantages in the prior art.

A further object of at least one aspect of the present invention is to facilitate bespoke fabncation of a spool piece to close a section between two pipe ends.

According to a first aspect of the invendon there is provided a positional offset measurement system for determining the spatial relationship between two surfaces comprising a first end assemble associated with a first surface and a second end assembly associated with a second surface wherein each end assembly is provided with at least two communication modules, such that signals transmitted between the first and second end assemblies by the communications modules can be used to determine the relative position of the first and second surfaces.

The use of magnetic coupled antenna in communications modules which are associated with two spaced surfaces means that different aspects of the transmitted signals can be used to determine the relative position and orientation of the surfaces relative to one another in a quick and efficient manner.

Preferably, a communication module of one end assembly includes at least one a transmitter and a communication module of the other end assembly indudes at east one receiver. In a preferred embodiment, each communication module includes at least one transceiver.

The provision of a transmitter at one end assembly and a receiver at the other end assembly enables the transmission of data from one end assembly to another end assembly. The provision of a transceiver in each communication module facilitates two way transmissions of signals from one end assembly to the other end assembly. In each case the transmission of data from one end assembly to the other end assembly enables data to be received which facilitates the determining of the orientation and relative position of the two surfaces.

Each of said at least one transmitter, receiver and transceiver may comprise a magnetic coupled antenna.

Transmission of signals using magnetic coupled antenna ensures that the effect of signal loss due to attenuation, particularly if the surfaces are located underwater, is minimized.

Preferably, each end assembly is provided with three or more communications modules. The provision of three or more communications modules enables triangulation of the communications modules to provide accurate data on aspects of orientation and relative position of the two surfaces.

One or more of the communications modules may be operable to move within a predetermined space relative to the associated end assembly.

By having at least one of the communications modules able to move within a predetermined space, a range of measurements may be incorporated within the data received thus facilitating the determination of the orientation and relative position of the two surfaces.

Each end assembly may be provided with a frame which offsets the communications modules from the associated surface by a predetermined amount in a direction parallel to a surface plane of the respective surface.

By being able to offset the communications modules from the associated surfaces any magnetic fidd effect created by the surfaces can be avoided thus minimizing the effect of the surfaces magnetic field on the operation of the magnetic coupled antenna of the communications modules.

Preferably the frame comprises at least two elongate members offset from one another and suitable for arrangement at opposing edges of the surface. Such an arrangement can ensure that, providing the dimensions of the surface is known, the arrangement of the frame can be used to facilitate determining the orientation and relative positions of the surfaces.

Preferably the elongate members are each provided with at least one communications module. The elongate members of at least one frame are each provided with two communications modules spaced apart on the elongate member such that the distance between the surface, the first communications module and the second communications module is predetermined.

By providing communications modules on the elongate members, particularly by providing the elongate members of at least one frame with two communications modules, the spacing of which is known, triangulation using data obtained from the transmitted signals is possible.

At least one end assembly is provided with a data processor. The data processor is able to interpret data obtained from received transmitted signals to determine orientation and relative positioning of the two surfaces.

Preferably, the signals transmitted from a communications module on a first surface received by a communications module on a second surface can, when combined with known system parameters. be used by the data processor to determine the rdative location and orientation of the first surface and second surface. By using a combination of known parameters and measured parameters the system can provide an accurate indication of the relative location and orientation of the surfaces.

Preferably, each communication module transmitter, receiver and/or transceiver has an electrically insirlated magnetic coup'ed antenna. Alternatively, each transceiver has an electric field coupled antenna. The antenna may be a wire loop, coil or similar arrangement.

Such antenna create both magnetic and electromagnetic fields. The magnetic or magneto-inductive field is generally considered to comprise two components of different magnitude that, along with other factors, attenuate with distance (r), at rates proportional to l/r2 and l/r3 respectively. Together they are often termed the near field components. The electromagnetic field has a still different magnitude and, along with other factors, attenuates with distance at a rate proportional to l/r. It is often termed the far field or propagating component.

Preferably. the data is transmitted as an electromagnetic and/or magneto-inductive signal.

Signals based on electrical and dectromagnetic fields are rapidly attenuated in water due to its partially electrically conductive nature. Propagating radio or electromagnetic waves are a result of an interaction between the electric and magnetic fields. The high conductivity of seawater attenuates the electric field. Water has a magnetic permeability close to that of free space so that a purely magnetic field is relatively unaffected by this medium. However, for propagating electromagnetic waves the energy is continually cycling between magnetic and electric field and this results in attenuation of propagating waves due to conduction losses.

The seawater provides attenuation losses in a workable bandwidth which still provide for data transmission over practical distances.

According to a second aspect of the invention there is provided a method of determining the spatial relationship between two surfaces comprising: providing a positional offset measurement system according to a first aspect of the invention; transmitting at least one signal from the first end assembly to the second end assembly; collecting data from the received signals; using collected data to facilitate determining the relative spatial relationship between the two surfaces.

Preferably. the method further comprises the step of using known system parameter data to further facilitate the determining of the relative spatial relationship between the two surfaces.

These and other aspects of the present invention will become apparent from the following description of various embodiments of the present invention which are given by way of example only with reference to the accompanying drawings in which: Figure 1 shows a schematic representation of a positiona' offset measurement system associated with two surfaces in accordance with a first embodiment of the present invention; Figure 2 shows a front end view of an end assembly according to another embodiment of the invention; Figure 3 shows a schematic representation of a positiona' offset measurement system associated with two surfaces in accordance with a further embodiment of the present invention; Figure 4a shows a schematic representation of a positiona' offset measurement system associated with two surfaces in accordance with a yet further embodiment of the present invention; and Figure 4b shows a cross section of the embodiment shown in Figure 3a.

Referring initially to Figure 1 there is shown a positiona' offset measurement system for determining the spatial relationship between two surfaces, the positional offset measurement system generally designated 10 according to a first embodiment of the present invention. The system 10 comprises a first end assembly 12 and a second end assembly 22. The first end assembly 12 is associated with a first surface i4 of first pipe i6 and a second end assembly 22 is associated with a second surface 24 of second pipe 26. First surface 14 and second surface 24 are arranged such that they are spaced apart from and offset from one another.

The first end assembly 12 is formed of a first frame iS which is provided with elongate members 19a and 19b which are in parallel with one another and which are arranged to extend from opposing sides of first surface 14 such that they extend from surface 14.

Communication modu'es 20a. 2Db are mounted on elongate member I 9a and communication modules 20c, 20d are mounted on elongate member 19b. The second end assembly 22 is formed of a second frame 28 which is provided with elongate members 29a and 29b which are in parallel with one another. Communication modules 30a, 3Db are mounted on elongate member 29a and communication modules 30c, 30d are mounted on elongate member 29b.

The second frame 28 is arranged such that extends from second surface 24.

The communication modules 20a, 2Db are mounted on dongate member I 9a, such that the distance A between the uppermost point 15 of first surface 14 and communications module 2Db and the distance B between communications module 2Db and communications module 20a are equal and known. The communication modules 20c, 20d; 30a, 3Db; 30c, 30d; are also spaced apart in the same manner.

Each end assembly 12,22 is further provided with a data processer II; 21 respectivdy which is in communication with communication modules 20a-d; 30a-d respectively.

In use, each communication module 20a-d at first end assembly 12 emits signals which are received by communications modules 30a-d at second end assembly 22. The received signals are sent to data processor 21 and using data gathered from the received signals, the distance and relative angles of offset between respective communication modules 2Da-d and 30a-d can be calculated. Similarly signals can be emitted by each communication module 30a-d at second end assembly 22 which are received by communications modules 20a-d at first end assembly 12. The received signals are sent to data process 11 and using data gathered from the received signals, the distance x and relative angles of offset, such as angle o, between respective modules 2Da-d and 3Da-d can be calculated. Using these calcirlated distances and angles. in conjunction with parameters and data known in relation to the first end assemNy 12 and second end assembly 22 including, but not limited to dimensions such as distances A and B, the cross section dimension of the pipes and the spacing apart of communications modules such as 20a and 20c; the positional offset of the first surface 14 and second surface 24 can be determined.

Figure 2 shows another embodiment of a first end assembly 12 ananged at first surface 14 of first pipe 16. b this embodiment, the elongate members 19a. 19b of frame 18 are arranged such that they extend perpendicularly from one another. As with the arrangement of Figure 1, communications modules 20a, 20b and 20c, 20d are mounted on elongate members l9a, l9b respectively. In this positional offset measurement system, the second end assembly 22 would minor the first end assemNy 12.

Figure 3 shows a positional offset measurement system for determining the spatial relationship between two surfaces, the positional offset measurement system generally designated 10. The system 10 comprises a first end assemNy 12 and a second end assemNy 22. The first end assembly 12 is associated with a first surface 14 of first pipe 16 and a second end assembly 22 is associated with a second surface 24 of second pipe 26. First surface 14 and second surface 24 are arranged such that they are spaced apart from and offset from one another.

In this embodiment, first end assembly 12 is formed of a first frame 18 which is provided with one elongate members 19 that extends from surface 14. Communication modules 20a, 2Db are mounted on elongate member i9. The second end assembly 22 is formed of a second frame 28 which is provided with elongate members 29a and 29b which are in parallel with one another. Communication modules 30a, 30b are mounted on elongate member 29a and communication modules 30c. 30d are mounted on elongate member 29b. The second frame 28 is arranged such that extends from second surface 24.

The communication modules 20a, 2Db are mounted on elongate member 19a, such that the distance A between the uppermost point i5 of first surface 14 and communications module 2Db and the distance B between communications module 2Db and communications module 20a are equal and known. The communication modules 30a, 3Db; 30c. 30d; are also spaced apart in the same manner.

Each end assembly 12, 22 is further provided with a data processer 11; 21 respectively which is in communication with communication modules 20a,b; 30a-d respectively.

In use, each communication module 20a,b at first end assembly 12 emits signals which are received by communications modules 30a-d at second end assembly 22. The received signals are sent to data processor 2i and using data gathered from the received signals, the distance and relative angles of offset between respective communication modules 20a,b and 30a-d can be calculated. Similarly signals can be emitted by each communication module 30a-d at second end assemNy 22 which are received by communications modules 20a,b at first end assembly 12. The received signals are sent to data process 11 and using data gathered from the received signals, the distance and rdative angles of offset between respective modules 20a,b and 30a-d can be calculated. Using these calculated distances and angles. in conjunction with parameters and data known in relation to the first end assembly 12 and second end assembly 22 including, but not limited to dimensions such as distances A and B, the cross section dimension of the pipes and the spacing apart of communications modules such as 30a and 30c; the positional offset of the first surface 14 and second surface 24 cati be determined.

In Figures 4a and 4b there is shown another embodiment of a positiona' offset measurement system for determining the spatial relationship between two surfaces. The positional offset measurement system 110 comprises a first end assembly 112 and a second end assembly 122.

The first end assembly 112 is associated with a first surface 114 of a first pipe 116 and second end assembly 122 is associated with second surface 24 of second pipe 126. First surface 114 and second surface 124 are arranged such that they are space apart from, and offset from, one another.

The first end assembly 112 is formed of a first frame 118 which includes an annular member 119 upon which communications modules I 20a,b are mounted such that they He at opposing perimeter edges of annular member 119. Communications modules 120a. bare operable to follow a rotational path around the perimeter defined by annular member 119 which corresponds with the exterior perimeter of surface 114. The second end assembly 122 is formed of a second frame 128 which includes an annular member 129 upon which communications modules 130a,b are mounted. Communications modules 130a,b are operable to follow a rotational path around the perimeter defined by annular member 129 which corresponds with exterior perimeter of surface 124. Each end assembly 112, 122 is further provided with a data processor III, 121 respectively which is in communication with modules 120a,b, 130a,b respectively.

In use, second end assembly 122 is actuated such that communications modules 130a,b rotate around the perimeter of second surface 124. Each communication modules 120a.b at first end assembly 112 emit signals which are received by communications modules 130a,b at second end assembly 122 with signals detected at intermittent periods as the second end assembly rotates. The received signals are sent to data processor 12i and using data gathered from the received signals, the distance and rdative angles of offset between respective communication modules 120a,b and 30a,b can be calculated. Similarly first end assembly 112 is actuated such that communications modules I 20a,b rotate around the perimeter of second surface 114. Signals emitted by each communication module 130a,b at second end assembly 122 are received by communications modules 120a,b at first end assembly 112 at intermittent periods as the first end assembly 112 rotates. The received signals are sent to data processor 11 and using data gathered from the received signals, the distance and relative angles of offset between respective modules 120a,b and l3Oa,b can be calculated. Using these calculated distances and angles. in conjunction with parameters and data known in relation to the first end assembly 112 and second end assembly 122 including, but not limited to dimensions the cross section dimension of the pipes and the spacing apart of communications modules such as 20a and 20b; the positional offset of the first surface i 14 and second surface 124 can be determined.

In each communication module of the above embodiments there can be provided a transmitter, receiver and/or transceiver (not shown) which has an electrically insulated magnetic coupled antenna. It will be appreciated that alternatively each transmitter, receiver or transceiver could also be an electric field coupled antenna. The antenna (not shown) may be a wire loop, coil or similar arrangement. Such antenna create both magnetic and electromagnetic fields. The magnetic or magneto-inductive field is generally considered to comprise two components of different magnitude that, along with other factors, attenuate with distance (r), at rates proportional to 1/r2 and l/r3 respectively. Together they are often termed the near field components. The electromagnetic field has a still different magnitude and, along with other factors, attenuates with distance at a rate proportional to hr. It is often

termed the far field or propagating component.

In each of the above embodiments, the data can be transmitted as an electromagnetic and/or magneto-inductive signaL Signals based on dectrical and electromagnetic fields are rapidly attenuated in water due to its partially dectricafly conductive nature. Propagating radio or electromagnetic waves are a result of an interaction between the electric and magnetic fields.

The high conductivity of seawater attenuates the electric field. Water has a magnetic permeability close to that of free space so that a purely magnetic field is relatively unaffected by this medium. However, for propagating electromagnetic waves the energy is continually cycling between magnetic and electric field and this results in attenuation of propagating waves due to conduction losses. The seawater provides attenuation losses in a workable bandwidth which still provide for data transmission over practical distances.

The principle advantage of the present invention is that the relative position and orientation of two surfaces relative to one another in a quick and efficient manner using data communicated by way of transmitted signals.

Various modifications can be made to the embodiments as hereinbefore described without departing from the scope of the invention. For example. although the first end assembly and second end assemNy have each been described as having up between two and four communications modules, it will be appreciated that each end assembly may have one or more communications modules depending on the relative interaction of communicafions modules enabling triangulation to help determine data which can be used to establish distance and offset parameters.

Claims (20)

1. Claims 1. A positional offset measurement system for determining the spatial relationship between two surfaces comprising: a first end assemble associated with a first surface, and a second end assembly associated with a second surface, wherein each end assembly is provided with at least two communication modules, such that signals transmitted between the first and second end assemblies by the communications modules can be used to determine the relative position of the first and second surfaces.
2. 2. A positional offset measurement system as daimed in daim I wherein a communication module of one end assembly includes at least one a transmitter and a communication module of the other end assembly includes at least one receiver.
3. 3. A positional offset measurement system as daimed in any preceding claim wherein provision of a transmitter at one end assembly and a receiver at the other end assembly enables the transmission of data from one end assembly to another end assembly.
4. 4. A positional offset measurement system as claimed in claim 1 or claim 2 wherein each communication module includes at least one transceiver.
5. 5. A positional offset measurement system as daimed in daim 4 wherein provision of a transceiver in each communication module facilitates two way transmissions of signals from one end assembly to the other end assembly.
6. 6. A positional offset measurement system as daimed in any one of claims 3 and 5 wherein transmission of data from one end assembly to the other end assembly enables data to be received by the other end assembly which facilitates the determining of the orientation and relative position of the two surfaces.
7. 7. A positional offset measurement system as claimed in any preceding claim wherein each of said at least one transmitter, receiver and transceiver may comprise a magnetic coupled antenna.
8. 8. A positional offset measurement system as daimed in any preceding daim wherein each end assembly is provided with three or more communications modules.
9. 9. A positional offset measurement system as daimed in any preceding claim wherein one or more of the communications modules is operable to move within a predetermined space relative to the associated end assembly.
10. 10. A positional offset measurement system as daimed in any preceding daim wherein each end assembly is provided with a frame which offsets the communications modules from the associated surface by a predetermined amount in a direction parallel to a surface plane of the respective surface.
11. 11. A positional offset measurement system as claimed in claim 10 wherein the frame comprises at least Iwo elongate members offset from one another and suitable for arrangement at opposing edges of the surface.
12. 12. A positional offset measurement system as daimed in daim II wherein the elongate members are each provided with at least one communications module.
13. 13. A positional offset measurement system as claimed in claim II or claim 12 wherein the elongate members of at east one frame are each provided with two communications modules spaced apart on the elongate member such that the distance between the surface, the first communications module and the second communications module is predetermined.
14. 14. A positional offset measurement system as claimed in any preceding claim wherein at least one end assembly is provided with a data processor.
15. 15. A positional offset measurement system as daimed in daim 14 where, the signals transmitted from a communications module on a first surface received by a communications module on a second surface can, when combined with known system parameters, be used by the data processor to determine the relative location and orientation of the first surface and second surface.
16. 16. A positional offset measurement system as claimed in any preceding claim wherein the at least one transceiver, receiver or transmitter of each communication module has an electrically insulated magnetic coupled antenna.
17. 17. A positional offset measurement system as claimed in any one of claims 1 to i6 wherein the at least one transceiver, receiver or transmitter of each communicationmodule has an electric field coupled antenna.
18. 18. A positional offset measurement system as claimed in any preceding claim wherein the data is transmitted as an electromagnetic and/or magneto-inductive signal.
19. 19. A method of determining the spatial relationship between two surfaces comprising: providing a positional offset measurement system according to any preceding claim; transmitting at least one signal from the first end assembly to the second end assembly; collecting data from the received signals; and using collected data to facilitate determining the relative spatial relationship between the two surfaces.
20. 20. A method of determining the spatial relationship between two surfaces as claimed in claim 16, the method further compnsing the step of using known system parameter data to further facilitate the determining of the relative spatial relationship between the two surfaces.