Apparatus, system, method and computer program for tribo-dynamic measurements

Abstract

An apparatus, system, method and computer program for controlling an application of a radial impact 301sc on a rotatable structure 301 of a tribological testing apparatus 300 for performing a tribo-dynamic measurement on a test component 401, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

Description

[0001] APPARATUS, SYSTEM, METHOD AND COMPUTER PROGRAM FOR TRIBO-DYNAMIC MEASUREMENTS

[0002] TECHNOLOGICAL FIELD

[0003] Examples of the present disclosure relate to an apparatus, system, method and computer program for tribo-dynamic measurements.

[0004] BACKGROUND

[0005] It is common practice to characterise structures / physical components using modal testing statically. However, this neglects the influence of tribological phenomenon such as lubrication films which influence rotating machinery / component’s dynamic properties significantly.

[0006] A rotating component such as a rolling element bearing requires a lubricant film within a contact between an inner / outer race and constituent rolling elements. Such a film supports a radial load, reduces friction, and increases durability of the individual rolling elements and raceways. The lubricant is entrained into the contact at a velocity that is the average of two surface velocities (inner / outer bearing raceway velocity and rolling element tangential velocity). With increasing entrainment speed, the lubricant’s central film thickness increases. The increase in film thickness increases the radial load within the rolling element contact. This increase in radial load causes an increase in localised surface elastic deformation to raceways and rolling elements. Accordingly, a consequence of the increased film thickness in a rolling element bearing (which increases with increase rotational speed) is that it alters the stiffness and damping properties of the rolling element bearing. In other words, a rolling element bearing’s stiffness and damping value changes / increases with increasing rotational speed of the rolling element bearing. Moreover, stiffness and damping values alter dynamic characteristics of the rolling element bearing such as shifting its resonant frequencies - which can effect its durability and efficiency.

[0007] It is desirable to perform a tribological assessment / test of a physical component (such as a roller element bearing) to determine its tribological properties. Moreover, it is desirable to perform dynamic (i.e. non-static) tribological assessments / tests of a physical component (such as a roller element bearing) to determine its tribological properties in motion / during use - i.e. to perform tribo-dynamic measurements to determine the physical component’s tribo-dynamic properties. Finally, it is desirable to obtain dynamic properties such as stiffness and damping which are affected by tribology.

[0008] Conventional systems for performing a tribological assessment of a physical component (such as a roller element bearing) to analyse durability and efficiency of the component are not always optimal. Conventionally, in order to analyse a rolling element bearing’s dynamic and tribological performance (e.g. to perform a tribo-dynamic measurement to characterise a stiffness / damping of the roller element bearing), impulse testing of a rotating structure is carried out that requires a user to manually hit a rotating shaft (to which the roller element bearing is coupled) with an impulse hammer or modal hammer. Consistent repeatability (i.e. repetition of similar impacts in similar locations) is desirable in impulse testing as this improves the quality of the measurement data. However, conventional manual impulse testing methodologies are prone to inaccuracies and human error (not least due to overloading the modal hammer’s load capacity). Also, they can be slow to perform and take a long time to conduct the tests (as well as perform post-test analysis of the results). Moreover, such a methodology also presents safety risks to the user, particularly for high shaft rotation speeds (e.g. above 4,000 or 8,000 rpm), whereas higher rotational speeds are relevant to modern applications including electric motors for electric vehicles, micro turbines and so on.

[0009] Until now, most automotive applications have been limited to 8,000 rpm for big end bearings, where the effects of higher lubricant entrainments speed are rarely reached. On the advent of the automotive industry shifting entirely towards electric vehicles for passenger transport, electric motor speeds are exceedingly high (30,000rpm+) relative to the internal combustion engine prime mover counterpart. These electric motors are spending longer times at these higher operating speeds, and therefore the prevalence of the tribo-dynamic interaction in rolling element bearings is becoming more significant.

[0010] In some circumstances it can be desirable to provide an apparatus for improving tribo- dynamic measurements, such as modal testing of rotating devices or machinery. In some circumstances it can be desirable to provide an apparatus for improving the accuracy of tribo-dynamic measurements. In some circumstances it can be desirable to provide an apparatus for improving the safety of performing tribo-dynamic measurements.

[0011] The listing or discussion of any prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects / examples of the present disclosure may or may not address one or more of the background issues.

[0012] BRIEF SUMMARY

[0013] The scope of protection sought for various embodiments of the invention is set out by the claims.

[0014] According to various, but not necessarily all, examples of the disclosure there are provided examples as claimed in the appended claims. Any examples and features described in this specification that do not fall underthe scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0015] According to at least some examples of the disclosure there is provided an apparatus comprising: radial impact control means configured to control an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribodynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0016] According to at least some examples of the disclosure there is provided a system comprising: the apparatus mentioned above, and impacting means configured to apply the radial impact.

[0017] According to various, but not necessarily all, examples of the disclosure there is provided a method comprising: controlling an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0018] According to various, but not necessarily all, examples of the disclosure there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform: controlling an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0019] According to various, but not necessarily all, examples of the disclosure the apparatus may be embodied as a chipset, circuitry, or module comprising means / processing circuitry configured to perform the above-mentioned functionality.

[0020] According to various, but not necessarily all, examples of the disclosure there is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: control an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0021] According to various, but not necessarily all, examples of the disclosure there is provided a non-transitory computer readable medium encoded with instructions that, when executed by at least one processor, causes at least the following to be perform: controlling an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0022] According to various, but not necessarily all, examples of the disclosure there is provided a method of providing and / or manufacturing an apparatus and / or system as described herein.

[0023] According to various, but not necessarily all, examples of the disclosure there is provided a method of using an apparatus and / or system as described herein.

[0024] The following portion of this 'Brief Summary’ section describes various features that can be features of any of the examples described in the foregoing portion of the 'Brief Summary’ section. The description of a function should additionally be considered to also disclose any means suitable for performing that function.

[0025] In some but not necessarily all examples, the information indicative of the position of the at least part of the rotatable structure comprises: a measurement indicative of a first position, along a first axis, of the at least portion of the rotatable structure; a measurement indicative of a second position, along a second axis different to the first axis, of the at least portion of the rotatable structure; and / or a measurement indicative of the position of the at least a part of the rotatable structure whilst the rotatable structure is rotating.

[0026] In some but not necessarily all examples, the radial impact control means is further configured to control the application of the radial impact based, at least in part, on angular information indicative of an orientation and / or rate of change of orientation of the at least part of the rotatable structure.

[0027] In some but not necessarily all examples, the radial impact control means is further configured to control to application of the radial impact so as to control: a location of the radial impact on the at least part of the rotatable structure; and / or a time of the radial impact on the at least part of the rotatable structure. In some but not necessarily all examples, the radial impact control means is further configured to control the application of the radial impact occurs at least one or more of: at a predetermined location on the rotatable structure; at a predetermined time; at a predetermined point in a cycle of rotation of the rotatable structure; with a predetermined force; and / or whilst the rotatable structure is rotating.

[0028] In some but not necessarily all examples, the application of the radial impact on a rotatable structure is applied via impacting means configured to apply the radial impact, and wherein the control of the application of the radial impact comprises controlling the impacting means.

[0029] In some but not necessarily all examples, the control of the application of the radial impact comprises controlling a trigger time of the impacting means.

[0030] In some but not necessarily all examples, the control of the application of the radial impact is further based, at least in part, on an estimated time for the impacting means to apply the radial impact to the rotating structure once triggered.

[0031] In some but not necessarily all examples, wherein the radial impact control means is configured to control the radial impact control means to apply a series of radial impacts whilst the rotatable structure is rotating, such that each radial impact of the series occurs: at a common predetermined location on the rotatable structure; at a common predetermined point in a cycle of rotation of the rotatable structure; and / or with a common predetermined force.

[0032] In some but not necessarily all examples, the rotatable structure is a rotatable shaft of the tribological testing apparatus and wherein the test component is coupled to the rotatable shaft.

[0033] In some but not necessarily all examples, the test component is a rolling element bearing.

[0034] While the above examples of the disclosure and optional features are described separately, it is to be understood that their provision in all possible combinations and permutations is contained within the disclosure. It is to be understood that various examples of the disclosure can comprise any or all of the features described in respect of other examples of the disclosure, and vice versa. Also, it is to be appreciated that any one or more or all of the features, in any combination, may be implemented by / comprised in / performable by an apparatus, a method, and / or computer program instructions as desired, and as appropriate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Some examples will now be described with reference to the accompanying drawings in which:

[0036] FIG. 1 shows an example of a method according to the present disclosure;

[0037] FIG. 2 shows an example of another method according to the present disclosure;

[0038] FIG. 3 schematically shows an example of an apparatus according to the present disclosure;

[0039] FIG. 4 schematically shows an example of a computer program according to the present disclosure;

[0040] FIG. 5 schematically shows an example of a system according to the present disclosure; and

[0041] FIG. 6 shows an example of another system according to the present disclosure.

[0042] The figures are not necessarily to scale. Certain features and views of the figures can be shown schematically or exaggerated in scale in the interest of clarity and conciseness. For example, the dimensions of some elements in the figures can be exaggerated relative to other elements to aid explication. Similar reference numerals are used in the figures to designate similar features. For clarity, all reference numerals are not necessarily displayed in all figures.

[0043] In the drawings (and description) a similar feature may be referenced by the same three- digit number. In the drawings (and description), an optional subscript to the three-digit number can be used to differentiate different instances of similar features. Therefore, a three-digit number without a subscript can be used as a generic reference and the three- digit number with a subscript can be used as a specific reference. A subscript can comprise a single digit that labels different instances. A subscript can comprise two digits including a first digit that labels a group of instances and a second digit that labels different instances in the group.

[0044] DETAILED DESCRIPTION

[0045] The figures schematically illustrate, and the following description describes, various examples of the disclosure including an apparatus 10 comprising: radial impact control means 11 configured to control an application of a radial impact 301scon a rotatable structure 301 of a tribological testing apparatus 300 for performing a tribo-dynamic measurement on a test component 401 , wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0046] FIG. 1 schematically illustrates an example of a method 100. It will be understood that the block as illustrated in FIG. 1 , as well as the further functions described below, can be implemented by various means, such as hardware, firmware, and / or software including one or more computer program instructions. For example, one or more of the functions described below can be performed by a single physical entity (such as the apparatus 10 described with reference to FIG. 3 which can be embodied in a chipset, circuitry, or module - such an apparatus comprising means for performing the below described functions). One or more of the functions described below can be implemented by a computer program (such as the computer program 14 as described with reference to FIG. 4 which can be stored by a computer readable storage device / memory and performed by a processor).

[0047] As will be appreciated, any such computer program instructions can be loaded onto a computer or other programmable apparatus (i.e. hardware) to produce a machine, such that the instructions when performed on the programmable apparatus create means for implementing the functions specified. These computer program instructions can also be stored in a computer-readable medium that can direct a programmable apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the blocks. The computer program instructions can also be loaded onto a programmable apparatus to cause a series of operational actions to be performed on the programmable apparatus to produce a computer-implemented process such that the instructions which are performed on the programmable apparatus provide actions for implementing the functions specified in the blocks.

[0048] One or more of the features discussed in relation to FIG. 1 can be found in one or more of the other FIGs. During the following discussion of FIG. 1 , use will be made of reference numerals of features shown in the other FIGs for the purposes of explanation.

[0049] In block 101 , an application of a radial impact 301 sc- on a rotatable structure 301 of a tribological testing apparatus 300 for performing a tribo-dynamic measurement on a test component 401 is controlled by a radial impact control means 11 , wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0050] In this regard, the radial impact control means (e.g. a controller 11 for controlling impacting means configured to apply the radial impact, such as a modal hammer and means for automating a triggering / actuation / activation / release of the modal hammer) is configured to control the application of a radial impact (e.g. to control means for applying a radial impact, such as an automated modal hammer 303) on the rotatable structure (e.g shaft 301 ) of the tribological testing apparatus (e.g. a tribological / tribo-dynamic test rig / machine) for performing tribo-dynamic measurements (e.g. impact testing for characterising tribo- dynamic properties such as stiffness and damping of the test component, e.g. rolling element bearing 401 , coupled to the rotatable structure / shaft 301 ). Moreover, the radial impact control means is configured to control the application of the radial impact based, at least in part, on information indicative of a position of at least a part of the rotatable structure (e.g. its horizontal and vertical displacement relative to a nominal axis of rotation of the rotatable structure whilst the rotatable structure is rotating).

[0051] In some examples, the radial impact on the rotatable structure is: an impulse, having a radial component, on the rotatable structure; or a dynamically variable radial load applied to the rotatable structure.

[0052] In some examples, the rotatable structure is a shaft, such as a shaft (which may be driven by a prime mover / motor spindle 402) of the tribological testing apparatus to which the test component is mechanically coupled.

[0053] In some examples, the tribological testing apparatus is a tribological test rig / machine for performing impact testing to characterise / measure tribo-dynamic properties of a test component (e.g. rolling element bearing) such as stiffness and damping of the test component.

[0054] In some examples, the test component is a bearing, such as a roller element bearing. Roller element bearings support a radial load and permit rotation in a multitude of mechanical systems, including: vehicle transmissions, electric motors, wind turbines and manufacturing equipment.

[0055] In some examples, the information indicative of a position of at least a part of the rotatable structure comprises: a measurement indicative of a first position, along a first axis, of the at least portion of the rotatable structure (for instance: a sensor measurement of a first displacement in a first direction, e.g. a first radial direction such as horizontal; a distance along a horizontal x axis; lateral position; or lateral displacement); and / or a measurement indicative of a second position, along a second axis different (e.g. orthogonal / perpendicular) to the first axis, of the at least portion of the rotatable structure (for instance: a sensor measurement of a second displacement in a second direction, e.g. a second radial direction such as vertical; a distance along a vertical y axis; vertical position; or vertical displacement).

[0056] The information indicative of a position of at least a part of the rotatable structure may be determined by means such as, for example, a position or displacement sensor. In some examples, the position of at least a part of the rotatable structure is determined whilst the rotatable structure is rotating

[0057] In some examples, the application of the radial impact is further controlled based, at least in part, on angular information indicative of an orientation and / or rate of change of orientation (e.g. angular velocity) of the at least part of the rotatable structure. Such information may be determined via means such, for example, as a sensor or accelerometer.

[0058] In some examples, the application of the radial impact is controlled so as to control: a location of the radial impact on the at least part of the rotatable structure; and / or a time of the radial impact on the at least part of the rotatable structure.

[0059] In some examples, the application of the radial impact is controlled (e.g. based on a measured translational position and angular velocity of the rotatable structure) such that the radial impact occurs at least one or more of: at a predetermined location on the rotatable structure; at a predetermined time; at a predetermined point in a cycle of rotation of the rotatable structure; with a predetermined force; and / or whilst the rotatable structure is rotating.

[0060] In some examples, the application of the radial impact on a rotatable structure is applied via impacting means configured to apply the radial impact. The impacting means may comprise an automatic modal hammer (e.g. a modal hammer and means for automating a triggering / actuation / activation / release of the modal hammer). The motion of moving the hammer can be controlled via a solenoid or stepper motor. The impacting means may be a shaker on ‘impulse mode’ (e.g. with a half sinusoidal motion profile) rather than a modal hammer / force sensor. The impacting means may be driven by: pneumatics (compressed gas / fluid), electric (piezo-electric, electromagnetic, stepper motor, servomotor or servo impactor), or a precise controlled explosion.

[0061] The radial impact control means 11 is configured to control the impacting means and its application of radial impact on a rotatable structure, not least to control a trigger time of the impacting means (i.e. at time at which the impacting means is triggered / actuated / activated / released to apply the radial impact).

[0062] In some examples, the application of the radial impact is further controlled based, at least in part, on an estimated time for the impacting means to apply the radial impact to the rotatable structure once triggered. By taking onto account: such an estimated time, a measured lateral displacement of the rotatable structure, a measured vertical displacement of the rotatable structure, a measured orientation and / or angular velocity of the rotatable structure, the radial impact can be controlled so as to occur: at a predetermined location on the rotatable structure; at a predetermined time; at a predetermined point in a cycle of rotation of the rotatable structure; and / or with a predetermined force. In some examples, a series of radial impacts is applied to the rotatable structure, whilst it is rotating, such that each radial impact of the series occurs: at a common predetermined location on the rotatable structure; at a common predetermined point in a cycle of rotation of the rotatable structure; and / or with a common predetermined force.

[0063] Advantageously, this may enable the performance of consistent repeatable impulse testing. Examples of the disclosure may thereby provide accurate and repeatable modal testing of rotating devices or machinery.

[0064] FIG. 2 illustrates an example of a further method 200 as previously described with reference to FIG. 1 . The description provided with reference to FIG. 1 is also relevant to FIG. 2. One or more of the features discussed in relation to FIG. 2 can be found in one or more of the other FIGs. During the following discussion of FIG. 2, use will be made of reference numerals of features shown in the other FIGs for the purposes of explanation.

[0065] In block 201 , a position of rotatable structure along lateral axis is determined, i.e. a lateral displacement of the rotatable structure as measured by one or more displacement sensors 304.

[0066] In block 202, a position of rotatable structure along vertical axis is determined, i.e. a vertical displacement of the rotatable structure as measured by one or more displacement sensors 304.

[0067] In block 203, an angular position / orientation and / or angular velocity of the rotatable structure is determined, i.e. as measured by one or more sensors 305.

[0068] In block 101 , the lateral, vertical and angular positional information is input to a radial impact control means 11 which uses the same (as discussed above) to control a triggering of an application of plural radial impacts on the rotatable structure, e.g. so as to provide a series of consistent impacts / impulses to the rotatable structure i.e. impacts occurring: at substantially the same location on the rotatable structure, at substantially the same point in a cycle of rotation of the rotatable structure, and with substantially the same force.

[0069] In block 204, one or more tribo-dynamic measurements are performed based on the series of consistent impacts / impulses on the rotatable structure.

[0070] FIG. 3 schematically illustrates a block diagram of an apparatus 10 for performing the above-described methods and providing the functionality described in the present disclosure. The apparatus comprises a controller 11 , which could be provided within a device such as a computer 302. In some, but not necessarily all examples, the apparatus can be embodied as a chip, chip set, circuitry or module. As used here 'module’ refers to a unit or apparatus that excludes certain parts / components that would be added by an end manufacturer or a user.

[0071] Implementation of the controller 11 can be as controller circuitry. The controller 11 can be implemented in hardware alone, have certain aspects in software including firmware alone or can be a combination of hardware and software (including firmware).

[0072] The controller 11 can be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 14 in a general- purpose or special-purpose processor 12 that can be stored on a computer readable storage medium 13, for example memory, or disk etc, to be executed by such a processor

[0073] 12.

[0074] The processor 12 is configured to read from and write to the memory 13. The processor 12 can also comprise an output interface via which data and / or commands are output by the processor 12 (e.g. to control an impacting means) and an input interface via which data and / or commands are input to the processor 12 (e.g. sensor measurements of positional information such as lateral and vertical displacement and angular orientation / velocity).

[0075] The apparatus can be coupled to or comprise one or more other components 15 (not least for example: sensors, impacting means, input / output user interface elements, other modules / devices / components for inputting and outputting data / commands, and / or other components and controllers of a tribo-dynamic test rig 300).

[0076] The memory 13 stores a computer program 14 comprising instructions (computer program instructions / code) that controls the operation of the apparatus 10 when loaded into the processor 12. The instructions of the computer program 14, provide the logic and routines that enables the apparatus to perform the methods described above and provide the functionality discussed in the present disclosure. The processor 12, by reading the memory

[0077] 13, is able to load and execute the computer program 14.

[0078] The computer program instructions may be comprised in a computer program, a non- transitory computer readable medium, a computer program product, a machine-readable medium. The term "non-transitory,” as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. RAM vs. ROM). In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0079] Although the memory 13 is illustrated as a single component / circuitry it can be implemented as one or more separate components / circuitry some or all of which can be integrated / removable and / or can provide permanent / semi-permanent / dynamic / cached storage.

[0080] Although the processor 12 is illustrated as a single component / circuitry it can be implemented as one or more separate components / circuitry some or all of which can be integrated / removable. The processor 12 can be a single core or multi-core processor.

[0081] The apparatus can include one or more components (e.g. sensors, impacting means, and / or other modules / devices / components of a tribo-dynamic test rig) for effecting the methods described above and provide the functionality discussed in the present disclosure. It is contemplated that the functions of these components can be combined in one or more components or performed by other components of equivalent functionality. The description of a function should additionally be considered to also disclose any means suitable for performing that function. Where a structural feature has been described, it can be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described.

[0082] Although examples of the apparatus have been described above in terms of comprising various components, it should be understood that the components can be embodied as or otherwise controlled by a corresponding controller or circuitry such as one or more processing elements or processors of the apparatus. In this regard, each of the components described above can be one or more of any device, means or circuitry embodied in hardware, software or a combination of hardware and software that is configured to perform the corresponding functions of the respective components as described above.

[0083] The apparatus can, for example, be a part of a tribo-dynamic test rig itself.

[0084] In some examples, the apparatus comprises: at least one processor 12; and at least one memory 13 storing instructions that, when executed by the at least one processor 12, cause the apparatus at least to: control an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0085] The apparatus can be for performing tribo-dynamic measurements.

[0086] The above-described examples find application as enabling components of tribo-dynamic test rigs / machines for performing tribo-dynamic measurements on test objects, not least for example roller element bearings. In some examples, there is provided a system comprising: an apparatus as described above, and one or more of: means configured to determine the information indicative of the position of the at least part of the rotatable structure; means configured to determine angular information indicative of an orientation and / or rate of change of orientation of the at least part of the rotatable structure; and impacting means configured to apply the radial impact.

[0087] FIG. 4, illustrates a computer program 14 which may be conveyed via a delivery mechanism 20. The delivery mechanism 20 can be any suitable delivery mechanism, for example, a machine-readable medium, a computer-readable medium, a non-transitory computer- readable storage medium, a computer program product, a memory device, a solid-state memory, a record medium or an article of manufacture that comprises or tangibly embodies the computer program 14. The delivery mechanism can be a signal configured to reliably transfer the computer program. An apparatus can receive, propagate or transmit the computer program as a computer data signal.

[0088] In certain examples of the present disclosure, there is provided a computer program comprising instructions, which when executed by an apparatus, cause the apparatus to perform at least the following or for causing performing at least the following: control an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

[0089] References to 'computer program’, 'computer-readable storage medium’, 'computer program product’, 'tangibly embodied computer program’ etc. or a 'controller’, 'computer’, 'processor’ etc. should be understood to encompass not only computers having different architectures such as single / multi- processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0090] Various, but not necessarily all, examples of the present disclosure can take the form of a method, an apparatus or a computer program. Accordingly, various, but not necessarily all, examples can be implemented in hardware, software or a combination of hardware and software.

[0091] Various, but not necessarily all, examples of the present disclosure are described using These program instructions can be provided to one or more processor(s), processing circuitry or controller(s) such that the instructions which execute on the same create means for causing implementing the functions specified in the block or blocks, i.e. such that the method can be computer implemented. The computer program instructions can be executed by the processor(s) to cause a series of operational block / steps / actions to be performed by the processor(s) to produce a computer implemented process such that the instructions which execute on the processor(s) provide block / steps for implementing the functions specified in the block or blocks.

[0092] Accordingly, the blocks support: combinations of means for performing the specified functions; combinations of actions for performing the specified functions; and computer program instructions / algorithm for performing the specified functions. It will also be understood that each block, and combinations of blocks, can be implemented by special purpose hardware-based systems which perform the specified functions or actions, or combinations of special purpose hardware and computer program instructions.

[0093] There now follows a discussion of issues with conventional impulse testing systems and methodologies and advantages that may be provided by examples of the present disclosure.

[0094] Conventionally, when performing impulse testing of rotating structures (e.g. roller bearing elements), it is very difficult to apply specific repeatable loads, even with the use of automatic modal hammers. This is due to a relative displacement between a force sensor surface (e.g. of the modal hammer) and a surface of the rotating object of interest, e.g. rotating shaft to which the impulse / load is to be applied.

[0095] An example of this is when a shaft is rotating at its 'critical speed’. This can be defined as: a rotational speed where the elastic restoring force of the shaft is equal to that of the centripetal force it is experiencing, and / or a rotational speed at which acting dynamic forces cause a machine component (e. g. shaft, rotor) to vibrate at its natural frequency.

[0096] For a rotating shaft there is a speed at which, for any small initial deflection, the centripetal force is equal to the elastic restoring force. At this point the deflection increases greatly and the shaft is said to "whirl".

[0097] At rotational velocities near the 'critical speed’, the shaft significant deflects / bends / bows. This is known as 'shaft whirl’. This deflection of the shaft alters the displacement between the force sensor and the rotating object. In order to apply a pre-calculated force, the displacement between the force sensor and the object of interest is required to be known. Another example of this is when the shaft has 'radial shaft run out’. This is a radial displacement measurement of a shaft as it rotates, i.e. when the axis of rotation is off- centre from a main axis, but still parallel thereto. The radial displacement alters the distance between the force sensor and the shaft surface. Other contributions to radial displacement can be: a motion introduced by a prime mover itself, any subsequent shaft alignment, bearing stiffness itself, as well as wear of the bearings’ surfaces. Shaft straightness can also effect the radial displacement.

[0098] Examples of the present disclosure seek to provide an apparatus, system, method and computer program that address issues of the shaft distorting / bending / bowing when rotating (particularly at high speeds) and which seek to improve the accuracy of damping / stiffness tribological measurements of a test bearing component (which involve the application of impacts to the shaft) by increasing the consistency / uniformity of the impacts (e.g. not least the impact location on the shaft).

[0099] FIG. 5 schematically illustrates a use case of examples of the present disclosure, namely impulse testing of rotating structures e.g. roller bearing elements. In this, an apparatus 10, as discussed above, is used with a tribo-dynamic test rig 300 to control radial impacts on a shaft 300 of the tribo-dynamic test rig, which is driven by a prime mover rotation driving device (not shown) and to which a test object is coupled (not shown).

[0100] The actual displacement shown in FIG. 5 is a combination of 'radial run out’, and vibration. In order to minimise variation of the impact location on the shaft surface, both of these phenomena need to be accounted for. By using 'Sensor 1’ (aligned along an x-axis) and 'Sensor 2’ (aligned along a y-axis) and a rotation sensor for the speed of rotation, alongside a signal conditioner and signal processing computer programme, an impact can be triggered at any desired status of the shaft (e.g. when the shaft is at highest amplitude / distortion). This process is repeatable.

[0101] The impacting means / impact mechanism has certain mechanical delay (i.e. there is a lag between a time at which a trigger signal is received and a time at which the impact is actually made on the shaft). This lag is taken into account, e.g. via an algorithm / computer programme, in determining when to trigger the impacting means.

[0102] This is particularly important for high speeds, where shaft deflections / bends are more pronounced and have a more significant effect on the application of specific repeatable impacts / impulses / loads. Examples of the disclosure are thereby applicable for modern applications, such as electric vehicles or high efficiency micro turbines, where experimental tribo-dynamic characterisations at high speeds would be needed.

[0103] FIG. 6 shows an example of a tribo-dynamic test rig 300 according to the present disclosure that allows for a safe and accurate tribo-dynamic characterisation of high-speed rolling element bearings and their respective lubricating fluids The test rig comprises a heavy machine bed which is used to mount two bearing blocks, and a loading tower. The bearing blocks support two rolling element bearings, at least one of which corresponds to the test component 401 whose tribo-dynamic properties (e.g. stiffness and damping) are to be characterised. The bearings in turn support a main test shaft 301 .

[0104] One end of the main test shaft is left free with no fixture on the end. The other end of the shaft is connected to a first coupling. The first coupling connects the main test shaft to a torque transducer via another shaft. The torque transducer is then connected to a spindle / rotational prime mover 402 via a second coupling and a yet further shaft.

[0105] A bearing axial preload device applies an axial load to an outer raceway of the bearing(s) under test.

[0106] The load tower helps to support a modal impact hammer and a shaker device. The load tower directly supports a linear rail guide which allows for a mounting bracket to slide freely in one direction, e.g. a vertical direction towards the main shaft. The modal hammer and shaker are both directly connected to the mounting bracket. The mounting bracket can either be moved via a pneumatic or solenoid impulse or shaker excitation (the impacting means 303 may comprise: the pneumatic or solenoid impulse or shaker excitation, the linear rail guide, and the modal impact hammer). Whilst Fig. 6 shows a pneumatic actuator for imparting the radial impact, it is to be appreciated that other impacting means could be used, not least for example a servo impactor.

[0107] A sensor bracket is mounted directly to the bearing block housing. The sensor bracket contains two motion (displacement) sensors 304, e.g. capacitive based sensors, that are aligned perpendicularly with respect to on another.

[0108] The motion sensors measure the motion of the shaft relative to the bearing block housing. One in a direction parallel to the direct excitation of the shaft (e.g. a radial / vertical direction). The other sensor measures the motion perpendicular to the initial excitation (e.g. a horizontal radial direction).

[0109] The torque transducer measures the torque required of the rotational prime mover / motor to rotate the shaft.

[0110] The modal hammer / shaker accelerometer acquire voltage signals which are passed through a conditioning amplifier and then to a data acquisition device, DAQ. The DAQ in turn passes the information to a computer which reads in the data. The torque transducer motion sensors are also connected to the same DAQ. The computer (i.e. radial impact control means 11 ) is used to control the shaker / pneumatics / solenoid (i.e. the impacting means 303) as well as the spindle / rotational prime mover.

[0111] The bearings may be lubricated via splash / drip lubrication feed via a heated recirculation sump, which can be controlled via a computer.

[0112] There now follows a discussion of a methodology of performing tribo-dynamic measurements / characterisations of a test component (i.e. bearing) using apparatuses and systems in accordance with the present disclosure.

[0113] A test is programmed via a computer. This includes detailing rotor test speeds (i.e. a number of discrete angular velocities of the shaft to test), an amount of axial preload, an impact load required (up to 2.2kN), and a number of repeats required at each test speed / impact load / axial preload required. The computer automatically runs the test without human intervention.

[0114] In each single test: o the computer controls the axial preload applied to the bearings. o the shaft’s angular velocity is controlled via the computer. o the computer remotely triggers the impacting means / mechanism o the modal hammer tip makes an impact directly to the main test shaft itself to excite the system. o The DAQ continuously captures data from the modal hammer, shaker, motion sensors and torque transducer.

[0115] The system repeats the following steps until the desired programme is complete.

[0116] One data post process method consists of: o a low pass filter is used to remove some of the undesirable noise. o the measured signals are further conditioned to remove extra sources of noise such as run out. o the computer uses software to compute a frequency response of the bearing-shaft-lubricant conjunctions relative to the impact / shaking (the bearing-shaft-lubricant conjunctions corresponding to a joint that comprises of a shaft seated within a bearing where lubrication is present) o the real component of a frequency response function, FRF, equates to the test component’s stiffness o the imaginary term of the FRF equates to the test component’s damping

[0117] Such a methodology and experimental test rig may aid the selection and design of efficient, durable rolling element bearings, such as rolling element bearings that can be found in many industrial applications including but not limited to: automotive, aviation, marine, and power generation applications.

[0118] It is to be noted there are other methods that can also be used that use time domain data and / or a system modelling approach etc.

[0119] Examples of the disclosure may thereby be used on a test rig that automates the process of characterising dynamic attributes of rolling element bearings, up to high speeds (e.g. 20- 30k rpm), with respects to the coupled interactions of tribology.

[0120] Various, but not necessarily all, examples of the present disclosure provide both a method and corresponding apparatus comprising various modules, means or circuitry that provide the functionality for performing / applying the actions of the method. The modules, means or circuitry can be implemented as hardware, or can be implemented as software or firmware to be performed by a computer processor. In the case of firmware or software, examples of the present disclosure can be provided as a computer program product including a computer readable storage structure embodying computer program instructions (i.e. the software or firmware) thereon for performing by the computer processor.

[0121] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0122] Features described in the preceding description can be used in combinations otherthan the combinations explicitly described.

[0123] Although functions have been described with reference to certain features, those functions can be performable by other features whether described or not.

[0124] Although features have been described with reference to certain examples, those features can also be present in other examples whether described or not. Accordingly, features described in relation to one example / aspect of the disclosure can include any or all of the features described in relation to another example / aspect of the disclosure, and vice versa, to the extent that they are not mutually inconsistent.

[0125] Although various examples of the present disclosure have been described in the preceding paragraphs, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as set out in the claims. For example, whilst the present disclosure has described examples of characterising roller bearing stiffness and damping during dynamics conditions, examples of the invention could be applied to other types of bearings and other test components, examples could also be used in full automotive, aeronautical, marine, power generation powertrains and drivetrains, manufacturing assembly lines. The term 'comprise’ is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X can comprise only one Y or can comprise more than one Y. If it is intended to use 'comprise’ with an exclusive meaning then it will be made clear in the context by referring to "comprising only one ...” or by using "consisting”.

[0126] In this description, the wording 'connect’ and 'couple’ and their derivatives mean operationally connected and coupled. It should be appreciated that any number or combination of intervening components can exist (including no intervening components), i.e. so as to provide direct or indirect connection and coupling. Any such intervening components can include hardware and / or software components.

[0127] As used herein, the term "determine / determining" (and grammatical variants thereof) can include, not least: calculating, computing, processing, deriving, measuring, investigating, identifying, looking up (for example, looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (for example, receiving information), retrieving / accessing (for example, retrieving / accessing data in a memory), obtaining and the like. Also, " determine / determining" can include resolving, selecting, choosing, establishing, and the like.

[0128] References to a parameter (for example position measurement, displacement, orientation), or value of a parameter, should be understood to refer to "data indicative of”, "data defining” or "data representative of” the relevant parameter / parameter value if not explicitly stated (unless the context demands otherwise). The data may be in any way indicative of the relevant parameter / parameter value, and may be directly or indirectly indicative thereof.

[0129] In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term ’example’ or 'for example’, 'can’ or 'may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some or all other examples. Thus 'example’, 'for example’, 'can’ or 'may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class.

[0130] In this description, references to "a / an / the” [feature, element, component, means ...] are used with an inclusive not an exclusive meaning and are to be interpreted as "at least one” [feature, element, component, means ...] unless explicitly stated otherwise. That is any reference to X comprising a / the Y indicates that X can comprise only one Y or can comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use 'a’ or 'the’ with an exclusive meaning then it will be made clear in the context. In some circumstances the use of 'at least one’ or 'one or more’ can be used to emphasise an inclusive meaning but the absence of these terms should not be taken to infer any exclusive meaning. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0131] The presence of a feature (or combination of features) in a claim is a reference to that feature (or combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result.

[0132] In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described. In the above description, the apparatus described can alternatively or in addition comprise an apparatus which in some other examples comprises a distributed system of apparatus, for example, a client / server apparatus system. In examples where an apparatus provided forms (or a method is implemented as) a distributed system, each apparatus forming a component and / or part of the system provides (or implements) one or more features which collectively implement an example of the present disclosure. In some examples, an apparatus is re-configured by an entity other than its initial manufacturer to implement an example of the present disclosure by being provided with additional software, for example by a user downloading such software, which when executed causes the apparatus to implement an example of the present disclosure (such implementation being either entirely by the apparatus or as part of a system of apparatus as mentioned hereinabove).

[0133] The above description describes some examples of the present disclosure however those of ordinary skill in the art will be aware of possible alternative structures and method features which offer equivalent functionality to the specific examples of such structures and features described herein above and which for the sake of brevity and clarity have been omitted from the above description. Nonetheless, the above description should be read as implicitly including reference to such alternative structures and method features which provide equivalent functionality unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0134] Whilst endeavouring in the foregoing specification to draw attention to those features of examples of the present disclosure believed to be of particular importance it should be understood that the applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon.

[0135] The examples of the present disclosure and the accompanying claims can be suitably combined in any manner apparent to one of ordinary skill in the art. Separate references to an "example”, "in some examples” and / or the like in the description do not necessarily refer to the same example and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For instance, a feature, structure, process, block, step, action, or the like described in one example may also be included in other examples, but is not necessarily included.

[0136] Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present disclosure. Further, while the claims herein are provided as comprising specific dependencies, it is contemplated that any claims can depend from any other claims and that to the extent that any alternative embodiments can result from combining, integrating, and / or omitting features of the various claims and / or changing dependencies of claims, any such alternative embodiments and their equivalents are also within the scope of the disclosure.

Claims

CLAIMSWe claim:1 . An apparatus comprising: radial impact control means configured to control an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

2. The apparatus of any previous claim, wherein the information indicative of the position of the at least part of the rotatable structure comprises: a measurement indicative of a first position, along a first axis, of the at least portion of the rotatable structure; a measurement indicative of a second position, along a second axis different to the first axis, of the at least portion of the rotatable structure; and / or a measurement indicative of the position of the at least a part of the rotatable structure whilst the rotatable structure is rotating.

3. The apparatus of any previous claims, wherein the radial impact control means is further configured to control the application of the radial impact based, at least in part, on angular information indicative of an orientation and / or rate of change of orientation of the at least part of the rotatable structure.

4. The apparatus of any previous claim, wherein the radial impact control means is further configured to control to application of the radial impact so as to control: a location of the radial impact on the at least part of the rotatable structure; and / or a time of the radial impact on the at least part of the rotatable structure.

5. The apparatus of any previous claim, wherein the radial impact control means is further configured to control the application of the radial impact such that the radial impact occurs at least one or more of: at a predetermined location on the rotatable structure; at a predetermined time; at a predetermined point in a cycle of rotation of the rotatable structure; with a predetermined force; and / or whilst the rotatable structure is rotating.

6. The apparatus of any previous claim, wherein the application of the radial impact on a rotatable structure is applied via impacting means configured to apply the radial impact, and wherein the control of the application of the radial impact comprises controlling the impacting means.

7. The apparatus of claim 6, wherein the control of the application of the radial impact comprises controlling a trigger time of the impacting means.

8. The apparatus of claim 6 to 7, wherein the control of the application of the radial impact is further based, at least in part, on an estimated time for the impacting means to apply the radial impact to the rotating structure once triggered.

9. The apparatus of any of claims 6 to 8, wherein the radial impact control means is configured to control the radial impact control means to apply a series of radial impacts whilst the rotatable structure is rotating, such that each radial impact of the series occurs: at a common predetermined location on the rotatable structure; at a common predetermined point in a cycle of rotation of the rotatable structure; and / or with a common predetermined force.

10. The apparatus of any previous claim, wherein the rotatable structure is a rotatable shaft of the tribological testing apparatus and wherein the test component is coupled to the rotatable shaft.

11. The apparatus of any previous claim, wherein the test component is a rolling element bearing.

12. The apparatus of any previous claim, wherein the apparatus is embodied in a chipset, circuitry, or module.

13. A system comprising: the apparatus of any previous claim, and impacting means configured to apply the radial impact.

14. The system of claim 13, wherein the impacting means comprises a modal hammer or an automated modal hammer.

15. The system of claim 13 or 14, further comprising means configured to determine the information indicative of the position of the at least part of the rotatable structure.

16. The system of claim any of claims 13 to 15, further comprising means configured to determine angular information indicative of an orientation and / or rate of change of orientation of the at least part of the rotatable structure.

17. The system of any of claims 13 to 16, wherein the system is a tribo-dynamic testing rig.

18. A method comprising: controlling an application of a radial impact on a rotatable structure of a tribological testing apparatus for performing a tribo-dynamic measurement on a test component, wherein the application of the radial impact is controlled based, at least in part, on information indicative of a position of at least a part of the rotatable structure.

19. A method of performing modal testing comprising the method of claim 18.

20. Computer program comprising instructions, which when executed by at least one processor, cause the apparatus of any of previous claims 1 to 12 to perform the method of claim 19 or 20.

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