WO2022118031A1

WO2022118031A1 - An impact target

Info

Publication number: WO2022118031A1
Application number: PCT/GB2021/053156
Authority: WO
Inventors: Jignesh Karsan Devshi PATEL; Lee Leslie DUCKWORTH; Billy Tyler Bootle TOPLEY
Original assignee: Batfast Cricket Centres Limited
Priority date: 2020-12-04
Filing date: 2021-12-02
Publication date: 2022-06-09
Also published as: AU2021393083A1; GB2596369A; US20240024748A1; EP4255591A1; GB2596369B; CA3203924A1; GB202019154D0

Abstract

An impact target for a sports simulator, the impact target comprising: a plate comprising a front surface and a rear surface opposite the front surface, the rear surface comprising an opening; and a vibration sensor fixedly positioned within the opening, the vibration sensor configured to detect an impact of a sports projectile with the impact target.

Description

AN IMPACT TARGET Field The present disclosure relates to an impact target for a sports simulator and a sports simulator. Summary According to a first aspect of the present disclosure there is provided an impact target for a sports simulator, the impact target comprising: a plate comprising a front surface and a rear surface opposite the front surface, the rear surface comprising an opening; and a vibration sensor fixedly positioned within the opening, the vibration sensor configured to detect an impact of a sports projectile with the impact target. Positioning the vibration sensor in the opening advantageously locates the vibration sensor closer to an impact surface of the impact target thereby improving sensitivity compared with an impact target with a sensor positioned on the rear surface. The plate may be configured to vibrate in response to the impact of the sports projectile with the impact target. The vibration sensor may be configured to detect a vibration in response to the impact of the sports projectile with the impact target. The opening may extend through a thickness of the plate from the rear surface to the front surface. The opening may extend entirely through a thickness of the plate from the rear surface to the front surface. The impact target may further comprise a cover plate overlying the opening on the front surface. The cover plate may comprise one or more perforations. The impact target may further comprise a cover sheet overlying the front surface of the plate. The impact target may comprise an air gap between the cover sheet and the front surface. The impact target may comprise a compressible seal arranged to separate the cover sheet from the front surface to provide the air gap. The vibration sensor may be mechanically mounted on a mount plate. The mount plate may be mechanically fixed to the rear surface of the plate. The mount plate may be mechanically coupled to the cover plate. The impact target may further comprise a second compressible seal between the mount plate and the rear surface. The opening may extend partially through a thickness of the plate from the rear surface towards the front surface. A portion of the plate between the front surface and the opening may be perforated. The impact target may further comprise a cover sheet overlying the front surface of the plate. The impact target may comprise an air gap between the cover sheet and the front surface. The impact target may comprise a compressible seal arranged to separate the cover sheet from the front surface to provide the air gap. A cross-section of the opening may be adapted to conform to a cross-section of the vibration sensor. The vibration sensor may comprise a piezo sensor. The piezo sensor may comprise a sensitive surface that faces towards the front surface of the plate. The vibration sensor may comprise an accelerometer. The rear surface may further comprise a one or more further openings. The impact target may further comprise one or more further vibration sensors respectively positioned in the one or more further openings. The impact target may comprise a damper for isolating the vibration sensor from ambient vibrations. According to a second aspect of the present disclosure there is provided a sports simulator comprising any of the impact targets disclosed herein. Brief Description of the Drawings One or more embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 illustrates a sports simulator comprising impact targets according to an embodiment of the present disclosure; Figure 2A illustrates a cross-sectional view of an impact target according to an embodiment of the present disclosure; Figure 2B illustrates a perspective view of the impact target of Figure 2A without a cover plate or a cover sheet attached; Figure 2C illustrates a perspective view of the impact target of Figure 2A and 2B with the cover plate attached; Figure 2D illustrates a cross-sectional and perspective view of an edge of the impact target of Figures 2A-2C with a cover sheet attached; Figure 2E illustrates a cross-sectional view of the impact target of Figures 2A- 2D comprising a transfer strut; Figure 2F illustrates a perspective view of a mount plate comprising a piezo sensor as used in the impact targets of 2A-2E; Figure 2G illustrates a perspective front view of the fully assembled impact target of Figures 2A-2E; Figure 2H illustrates a front view of the fully assembled impact target in a sports simulator; Figure 2I illustrates a perspective rear view of the fully assembled impact target of Figures 2A-2E; Figure 3 illustrates an impact of a sports projectile with an impact target according to an embodiment of the present disclosure; Figure 4 illustrates another impact target according to an embodiment of the present disclosure; Figure 5 illustrates a further impact target according to an embodiment of the present disclosure; Figure 6 illustrates a further impact target according to an embodiment of the present disclosure; and Figure 7 illustrates a further impact target according to an embodiment of the present disclosure. Detailed Description Sports simulators may be used for sports training and / or in an entertainment setting, and can include a simulated reality in which users experience various aspects of a sport or game. Use of a sports simulator may include a user striking a ball towards one or more targets. In some sports simulators, such as a golf simulator, a user may strike a stationary ball towards the one or more targets. In other example sports simulators, such as a baseball simulator or a cricket simulator, a projectile or ball may be launched towards a user who can swing a limb, bat or racquet in an attempt to strike the ball towards the one or more targets. Some sports simulators may implement ball tracking with a series of cameras to determine a trajectory of a ball struck by a user to provide feedback to the user. The feedback may comprise a score based on the trajectory of the ball. The score may relate to a gameplay score in an entertainment setting or to a quality score in a sports training setting. However, camera-based ball tracking can be expensive and the required computational processing can result in a lag time between the user striking the ball and receiving the feedback. The present disclosure relates to an impact target responsive to an impact of a sports projectile with the impact target. Such impact targets can include an impact sensor that provides the feedback to the user more rapidly than ball tracking. Examples of the present disclosure include impact targets with increased sensitivity to impacts. Additionally or alternatively, examples of the present disclosure include impact sensors that are both mechanically robust to high impact forces and have a high sensitivity for detecting low impact forces. Figure 1 illustrates a sports simulator comprising one or more impact targets according to an embodiment of the present disclosure. In this example, the sports simulator is a cricket simulator 100. The simulator 100 comprises a projectile launcher 102 for launching a sports projectile 104 (a ball in this example) towards a user 106. In response, the user can strike the projectile 104 towards one or more impact targets 108. The one or more impact targets 108 can detect an impact of the projectile 104 with the impact target 108 and provide feedback to the user 106. The impact target 108 may provide a visual indication to the user 106 from the target itself or via a separate display screen 110. In this example, the display screen 110 comprises an aperture though which the projectile launcher 102 launches the projectile 104 towards the user 106. The display screen 110 may itself comprise one or more impact targets 108. In this example, a further impact target 108’ may be arranged for impact with the sports projectile 104 in the event that the user 106 fails to strike the projectile 104. Figures 2A-2I illustrate cross-sectional and perspective views of an impact target 208 according to an embodiment of the present disclosure. The figures illustrate various sections of the impact target 208 at various stages of assembly. The impact target 208 comprises a plate 212 comprising a front surface 214 and a rear surface 216 opposite the front surface 214. The rear surface 214 comprises an opening 218 which may also be referred to as a cavity, a pocket or an aperture. A vibration sensor 220 is fixedly positioned within the opening 218. The vibration sensor 220 is configured to detect an impact of a sports projectile with the impact target 208. The impact sensor 208 may comprise an impact surface for receiving an impact from a sports projectile. In some examples, the impact surface may comprise the front surface 214 of the plate 212. In other examples, the impact target 208 may comprise a cover sheet 222 covering the front surface of the 214 of the plate 212. In such examples, the impact surface may be provided by the cover sheet 222. The cover sheet 222 may deform in response to the impact and, in turn, the cover sheet may impact the front surface 214 of the plate 212. Either way, the plate 212 is arranged with the front surface 214 towards an expected direction of impact. Positioning the vibration sensor 220 in the opening 218 advantageously locates the vibration sensor 220 closer to the impact surface of the impact target 208 thereby improving sensitivity compared with an impact target with a sensor positioned on the rear surface 216. Furthermore, by locating the vibration sensor 220 closer to vibration axes in the plane of the plate 212, the vibration sensor 220 can undergo a larger vibrational displacement when the plate 212 vibrates in response to an impact, further improving sensitivity. In addition, the enclosed pocket formed by the opening 218 can concentrate, channel and / or focus air vibrations (or pressure waves) around the vibration sensor 220 which can further improve the sensitivity of the impact target 208, particularly in examples wherein the vibration sensor 220 is a piezo sensor. In this example, the vibration sensor comprises a piezo sensor 220. However, in other examples the vibration may comprise an accelerometer or other vibration sensors known in the art. The piezo sensor 220 includes a sensitive surface 224 that faces towards the front surface 214 of the plate 212 and the impact surface. The sensitive surface 224 includes an aperture 226 that can detect vibration from acoustic waves or pressure waves of air incident on the aperture 226. Such pressure waves may be provided by movement of the piezo sensor 220 relative to the surrounding air which may arise from: (i) movement of the piezo sensor 220 due to its mechanical coupling to the plate 212 which can vibrate in response to the impact of the sports projectile with the impact surface; and / or (ii) air pressure waves generated within the opening 218 due to the impact. The piezo sensor 220 can output an electrical signal in response to the detection of a pressure wave. The impact target 208 may use the electrical signal to provide feedback to the user in any way that is known in the art including visual, audio and haptic feedback. The plate 212 may be considered as a chassis of the impact target 208. The dimensions of the plate 212 can affect the sensitivity of the impact target. For example, thick plates with larger surface areas may be less sensitive to impacts, particularly for impacts located towards the edge of the plate 212. Typically, there may be a trade- off between using a thick plate for robustness to high force impacts versus using a thin plate to enable a large surface area target. As described herein, the disclosed impact targets benefit from an increased sensitivity for a particular set of dimensions, thereby alleviating the plate thickness / area / sensitivity trade-off to an extent. The plate may comprise wood, metal, metal alloy or high density plastic. In one example, the plate comprises High Density Poly Ethylene (HDPE). In some examples, the impact target may comprise a 0.5 x 1 m HDPE plate. In other examples, the impact target may comprise a 1.0 x 1.0 m plywood plate. In further examples, the plate may comprise a larger surface area and include multiple openings with respective vibration sensors as discussed below in relation to Figure 7. In this example, the opening 218 extends through a thickness of the plate 212 from the rear surface 216 to the front surface 214, as can be seen in Figure 2A. Extending the opening through the entire thickness of the plate 212 can make the impact target 208 easier to manufacture. In one or more examples, a cross-sectional area of the opening 218 may be dimensioned to conform to a cross-sectional area of the piezo sensor 220. For example, a ratio of a cross-sectional area of the opening 218 to a cross sectional area of the piezo sensor 220 may be from 1.0 to 5.0, for example, 1.0 to 2.0 or 1.0 to 1.5. Conforming a cross-section of the opening 218 to the cross-section of the piezo sensor 220 can provide a snug fit and advantageously improve a coupling between the piezo sensor 220 and vibrations in the plate 212. The snug fit may also increase the robustness of the impact target 208. Minimising a cross-section of the opening may also maintain the structural integrity of the plate 212 and provide a robust impact target 208. In this example, the impact target 208 further comprises a cover sheet 222 covering the front surface 214 of the plate 212. The cover sheet 222 may comprise a flexible material which can flex or deform in response to the impact of the sports projectile. The cover sheet 222 may be transparent, thereby enabling artwork to be displayed between the front surface 214 of the plate 212 and the cover sheet 222. The cover sheet 222 can protect the artwork from scuffs resulting from an impact with the sports projectile. In some examples, the cover sheet 222 comprises Polyethylene Terephthalate Glycol (PETG). PETG is both weatherproof and UV proof, thereby making the impact target 208 particularly suitable for outdoor use. The cover sheet 222 can protect the piezo sensor 220 in the opening 218 from direct impacts with the sports projectile. The cover sheet 222 may be spaced apart from the front surface 214 of the plate 212 to provide an air gap 232 or spacing between the front surface 214 of the plate 212 and the cover sheet 222. In response to an impact of a sports projectile with the cover sheet 222, the cover sheet 222 will deform towards the front surface 214 of the plate 212 creating a shockwave or pressure wave in the air gap 232. The shockwave may travel through the air gap in a plane parallel to the front surface 214. The piezo sensor 220 can detect the shockwave as it travels through the air gap 232 to the opening 218. The opening 218 may concentrate or focus the shockwave thereby increasing a magnitude or amplitude of the shockwave as it reaches the aperture 226 of the piezo sensor 220. In this way, the cover sheet 222 can further enhance the sensitivity of the impact target 208. For example, in a scenario where an impact force of the sports projectile hitting the impact target 208 is insufficient to cause vibration of the plate 212, the shockwave generated by the cover sheet 222 may still generate a detectable pressure wave for the piezo sensor 220. The impact target 208 may further comprise a compressible seal 234. The compressible seal 234 may be positioned between the front surface 214 and the cover sheet 222 to separate the front surface 214 from the cover sheet 222 and provide the air gap 230. The compressible seal 234 may be placed around a perimeter of the front surface 214 of the plate 212. The compressible seal 234 may provide the cover sheet 222 with a spring / elastic effect such that the cover sheet 222 and compressible seal 234 can deform in response to an impact before returning to its original shape. The compressible seal 234 may comprise foam, rubber or any other suitable material as known in the art. In one example the compressible seal may comprise ethylene propylene diene monomer (EPDM). In some examples, the impact target 208 may comprise a retainer 236 (shown in Figures 2D and 2I) that clamps the plate 212, the cover sheet 222 and the compressible seal 234. The retainer 236 may clamp the items with the compressible seal 234 under partial compression. Figure 2D illustrates a perspective cross-sectional view at an edge of the plate 212 of the impact target 208. In this example, the retainer 236 is a retaining bracket clamping the compressible seal 234 between the cover sheet 222 and the plate 212 to provide the air gap 232. In some examples, the retaining bracket may be provided around the perimeter of the plate 212 to hold the impact target together (see Figures 2G to 2I). In the illustrated example, the impact sensor 208 further comprises a cover plate 228 (visible in Figures 2A, 2C and 2E) overlying or closing the opening 218 on the front surface 214 of the plate 212. The cover plate 228 may be fixed to fastenings 230 on the front surface 214 of the plate 212. The cover plate 228 may reside in a recess on the front surface 214. The cover plate 228 may vibrate or reverberate independently of, or as a superposition to, any vibration of the plate 212. As the cover plate 228 is located directly above the piezo sensor 220, the vibration of the cover plate 228 can advantageously increase a magnitude or amplitude of pressure waves incident on the piezo sensor 220 for a particular impact force. The cover plate 228 may vibrate in response to vibrations of the plate 212. The cover plate 228 may cooperate with the cover sheet 222 and vibrate in response to the shockwave produced by the cover sheet 222. In this way, the cover plate 228 may vibrate in response to impacts with an impact force, or position of impact, for which the plate 212 does not vibrate. In some examples, the cover plate 228 can advantageously provide protection for the cover sheet 222. In the absence of a cover plate 228, a sports projectile incident directly over the opening 218 may deform the cover sheet into the opening 218 and cause the cover sheet 222 to fracture. The cover plate 228 can prevent such excessive deformation and prevent or reduce the likelihood of any fracturing of the cover sheet 222. In some examples, the cover plate 228 may be perforated (comprise one or more holes). A perforated cover plate may permit air flow into and out of the opening 218. As a result, the perforated cover plate may advantageously transfer air pressure waves resulting from an impact through the perforated cover plate 228 into the opening 218. In some examples, the perforations may transfer the shockwave, provided by the cover sheet 222, into the opening 218. This may advantageously concentrate or increase a magnitude of the shockwave. In this example, the piezo sensor 220 is mounted on a mount plate 238 that is mechanically coupled to the rear surface 216 of the plate 212. The mount plate 238 may be coupled to the rear surface by mechanical fixings and/or fastenings. The rear surface 216 of the plate 212 may have one or more nylon fasteners for mounting the mount plate mount plate 238 with corresponding fixings. Nylon fasteners may advantageously allow the mount plate 238 to vibrate and the nylon fasteners to flex without working loose from the rear surface 216. The piezo sensor 220 may be mechanically mounted on the mount plate 238. Mechanically coupling the piezo sensor 220 to the plate 212 can provide a robust impact target 208 that can withstand high impact forces without dislocation of the piezo sensor 220. The mechanical mount plate 238 may comprise a clamp 240 for securing wires of the piezo sensor 220 and wires of a connection port 242 to further improve robustness to high impact forces. Securing wiring of the impact target 208 can prevent wiring joint dislocation resulting from repetitive high impact forces. In some examples, the impact target 208 may comprise a second compressible seal (not illustrated) between the rear surface 216 and the mount plate 238. The second compressible seal can enable the mount plate 238 to vibrate or flex relative to the plate 212 in response to an impact with the target surface. For example, the mount plate 238 may tend to vibrate at a different natural vibration frequency to the plate 212. The second compressible seal may also provide water ingress protection to the opening 208 aiding suitability of the impact target 208 for outdoor use. In some examples, the mount plate 238 may be directly mechanically coupled or connected to the cover plate 228. For example, one or more struts 244 (shown in Figure 2E) or transfer studs may extend between and connect the mount plate 238 and the cover plate 228. In this way, vibrations on the cover plate 228 may be transferred to the mount plate 238 and the piezo sensor 220, further enhancing sensitivity of the impact target 208. Figures 2G and 2H illustrate views of the front of the impact target 208 fully assembled. Artwork is installed under the cover sheet 222 obscuring the view of the cover plate 218. The retaining brackets 236 extend around the perimeter of the impact target 208. Figure 2I illustrates a perspective view of the rear of the impact target 208 fully assembled. The mount plate 238 is installed over the opening 218. The connection port 242 is accessible for connection to external circuitry. As discussed below, the connection port 242 can provide an output signal from the piezo sensor 220 in response to impacts of the sports projectile with the impact target 208. The connection port may also provide electrical power to circuitry of the impact target 208 Figure 3 illustrates the operation of the impact target 308 of Figure 2 in response to an impact with a sports projectile, according to an embodiment of the present disclosure. In this example, a sports projectile in the form of a ball 304 impacts the impact target 308. In Figure 3, the impact surface comprises the cover sheet 322. The cover sheet 322 deforms in response to the impact force exerted by the ball 304. The cover sheet 322 deforms such that the cover sheet 322 impacts the front surface 314 of the plate 312. In this way, the cover sheet 322 can transfer the impact force of the ball 304 to the front surface 314. The impact of the ball 304 on the cover sheet 322 produces a shockwave 348 in the air gap 332 between the cover sheet 322 and the plate 312. The shockwave 348 travels along a plane parallel to the front surface 314 towards the opening 318. The cover plate 328 may vibrate in response to the shockwave 348 to transfer energy in the shockwave (via an air pressure wave) to the opening 318 and the piezo sensor 320. Any perforations in the cover plate 328 may also transfer and may concentrate energy in the shockwave (via a pressure wave) into the opening 318 and onto the piezo sensor 320. The impact of the cover sheet 322 on the front surface 314 of the plate, in response to the impact of the ball 304, also produces a vibration 346 in the plate 312. The plate 312 may vibrate about an axis 350 through a centre of the thickness of the plate parallel to the front surface 314. The piezo sensor 320 can detect the vibration 346 of the plate 312 as it is mechanically coupled to the plate 312 via mount plate 338. The piezo sensor 320 may undergo a large displacement in response to the vibration because of the position of the piezo sensor 320 close to the axis 350. The motion of the piezo sensor 320 within the opening 318 relative to the surrounding air may further amplify the sensing effect. In summary, the piezo sensor 320 is arranged within an opening / cavity of the plate 312 to enhance its sensitivity to vibrations 346 of the plate 312 and shockwaves 348 produced by the cover sheet 322. Placing the piezo sensor 320 within the opening and closer to the front surface 314 than if it was mounted on the rear surface 316 can improve sensitivity to impacts of the plate 312. In turn, this can enable a relatively large impact target to be produced that can adequately sense an impact at its periphery. Figure 4 illustrates an impact target 408 according to a further aspect of the present disclosure. Features of the impact target that are present in the embodiment of Figure 2 have been given corresponding numbers in the 400 series and will not necessarily be described again here. The impact target 408 comprises a plate 412 comprising a front surface 414 and a rear surface 416 opposite the front surface 414. The rear surface 414 comprises an opening 418. A vibration sensor 420 is fixedly positioned within the opening 418. The vibration sensor 420 is configured to detect an impact of a sports projectile with the impact target 408. In this embodiment, the opening 418 extends through the entire thickness of the plate 412. However, the impact target 408 comprises neither the cover plate nor cover sheet of Figure 2. The impact target 408 provides a simple arrangement with minimal components. In some examples, a cross-section of the opening may have a diameter that is smaller than a diameter of the sports projectile. This can advantageously prevent the sports projectile from directly impacting the vibration sensor 420 and prevent it being damaged by the projectile. Positioning the vibration sensor 420 in the opening 418 advantageously locates the vibration sensor 420 closer to the impact surface (the front surface 416 in this example) of the impact target 408 thereby improving sensitivity compared with an impact target with a sensor positioned on the rear surface 416. Furthermore, by locating the vibration sensor 420 closer to vibration axes in the plane of the plate 412, the vibration sensor can undergo a larger vibrational displacement when the plate 412 vibrates in response to an impact, further improving sensitivity. In addition, the channel formed by the opening 418 can concentrate, channel and / or focus air vibrations (or pressure waves) around the vibration sensor 420 which can further improve the sensitivity of the impact target 408, particularly if the vibration sensor comprises a piezo sensor. The vibration sensor 420 can advantageously detect vibrations in the plate 412 in the same way as described above in relation to Figure 2. In some examples, the vibration sensor may comprise a piezo sensor 420 which may detect air vibrations or pressure waves that travel along the front (impact) surface 416 in response to an impact with a sports projectile. The pressure waves can channel and concentrate into the opening 418 arriving at the piezo sensor 420. Figure 5 illustrates a further impact target 508 according to another embodiment of the present disclosure. Features of the impact target 508 that are present in the embodiment of Figure 2 have been given corresponding numbers in the 500 series and will not necessarily be described again here. The impact target 508 comprises a plate 512 comprising a front surface 514 and a rear surface 516 opposite the front surface 514. The rear surface 514 comprises an opening 518. A vibration sensor 520 is fixedly positioned within the opening 518. The vibration sensor 520 is configured to detect an impact of a sports projectile with the impact target 508. In this example, the opening 518 extends partially through the thickness of the plate 512. As a result, an integral cover 552 (integral to the plate 512) separates the opening 518 from the front surface 514 and the impact surface. In the same way as the examples discussed above, the vibration sensor 520 is located in opening 518 of the impact target 508 such that it has improved sensitivity. In this example, the vibration sensor is a piezo sensor 520. In this example, the impact surface comprises the cover sheet 522. The cover sheet 522 may produce a shockwave in the same way as described in relation to Figure 2. The integral cover 552 may have a natural vibration frequency different to a natural vibration frequency of the plate 512. As a result, the integral cover may vibrate or reverberate at its own frequency directly in front of the opening 518 and the piezo sensor 520. In this way, the integral cover 552 may function in a similar way to the cover plate of Figure 2 and increase a magnitude or amplitude of air vibrations in the opening 518 and incident on the piezo sensor 520. The integral cover 552 may vibrate in response to vibrations of the plate 512 and / or in response to the shockwave produced by the cover sheet 522. In some examples, the integral cover may comprise one or more perforations for transferring pressure waves from the air gap 532 to the opening 518 in the same way as described in relation to the cover plate of Figure 2. In one or more further example impact targets, the vibration sensor may be an accelerometer or other vibration sensor known in the art. Although the example impact targets of Figures 2 to 5 are predominantly disclosed in relation to a piezo sensor the features of each of the figures may equally apply to an impact target comprising a vibration sensor other than a piezo sensor. Only features that solely rely on the direct detection of an air pressure wave incident on the aperture of the piezo sensor may not apply to other vibration sensors such as an accelerometer. However, impact targets incorporating other vibration sensors such as an accelerometer may indirectly detect an air pressure wave. For example, if the piezo sensor of Figure 2 was replaced with an accelerometer, the accelerometer could indirectly detect the air shock wave produced by the cover sheet in examples including a cover plate mechanically connected to the mount plate. A person skilled in the art will appreciate that all features of Figures 2 to 5 not related to the direct detection of an air pressure wave can apply to impact targets comprising an accelerometer or other vibration sensor. For example, features related to: detection of the mechanical vibration of the plate; the mechanical arrangement of the impact target; the opening; the mount plate; the cover sheet; the cover plate; the first and second compressible seals; the transfer struts; the retainer, among others may be implemented in embodiments comprising an accelerometer or other non-piezo based vibration sensor. The vibration sensor of all embodiments is arranged to detect an impact of a sports projectile with the impact target. The vibration sensor may detect vibrations of the plate and / or air vibrations or pressure waves resulting from the impact. The vibration sensor may generate an electrical signal in response to detecting the impact. For example, the air pressure waves or acoustic waves incident on a piezo element of the piezo sensor may alter a resistance of the piezo element which can be detected by circuity. As a further example, an accelerometer can provide an electrical signal in response to mechanical vibrations. Such operations are known in the art and not described in detail here. The impact target may comprise circuity for generating an output signal in response to the electrical signal. The output signal may comprise the electrical signal or may comprise parameters of the electrical signal, an amplified version of the electrical signal and / or a digital representation of the electrical signal. The impact target may comprise one or more transmission components for transmitting the output signal. For example, the impact target may provide for wireless or wired communication (for example via the connection port) for transmitting the output signal to a remote processor. The remote processor may form part of a sports simulator and provide feedback to a user. The feedback may comprise an indication that the impact target has been hit or a score dependent on the impact force, impact target location and / or a time of impact. The feedback may be provided by LEDs or a display screen. In some examples, the impact target may comprise a visual indicator for providing the feedback directly to the user. The visual indicator may be directly connected to the vibration sensor or circuitry and provide near instantaneous feedback to the user. For example, the impact target may comprise one or more LEDs, LCDs or other display devices suitable for providing the feedback to the user. In some examples, the impact target may comprise a processor for processing the electrical signal from the vibration sensor. The processor may control the visual indicator in response to the electrical signal. Alternatively, the processor may control a communication module to communicate the output signal to an external screen, device or processor. In some examples, the processor may apply one or more thresholds to the electrical signal from the vibration sensor. For example, the processor may apply a lower level threshold to the electrical signal. The processor may determine an electrical signal to correspond to an impact at the impact target if a level of the electrical signal is greater than or equal to the lower level threshold. The processor may determine an electrical signal to correspond to ambient noise or ambient vibrations if a level of the electrical signal is less than the lower level threshold. In this way, the impact target may avoid false positive impact detections arising from ambient noise or vibrations (for example a user walking past the impact target). In some examples, the impact target may comprise one or more mechanical dampers. The one or more mechanical dampers can isolate the impact target from vibrations in its surrounding environment. The mechanical dampers may form part of a stand or mounting bracket for positioning the impact target. Isolating the impact target from vibrations in the surrounding environment can further improve the sensitivity of the impact target to low force impacts. Figure 6 illustrates a further impact target 608 according to an embodiment of the present disclosure. The impact target 608 comprises two assemblies according to the example of Figure 2 mechanically coupled back to back. The impact target 608 operates under the same principles as the example of Figure 2. However, the back to back arrangement provides at least two opposing impact surfaces that are sensitive to impacts with a sports projectile. The impact target 608 may be particularly suitable for use as a backstop target in a baseball simulator or a wicket in a cricket simulator. The impact target may be sensitive to impacts from any direction making it particularly suitable for simulation of a run-out. Figure 7 illustrates a further impact target 708 according to an embodiment of the present disclosure. In this example, the impact target 708 comprises a plurality of vibration sensors housed in a respective plurality of openings 718-A, 718-B, 718-C, 718-D on the rear surface of the plate. In this example, the impact target comprises four vibration sensors arranged in four quadrants of the impact target. Providing a plurality of vibration sensors can be particularly advantageous for large area impact targets such as those used as the display screen in Figure 1. Providing a plurality of vibration sensors may also enable the impact target to determine a position of impact on the impact surface. In this example, each vibration sensor can produce a corresponding electrical signal. The impact target may provide an output signal as described above in relation to the other sensors. The impact target may comprise a processor for receiving the plurality of electrical signals. The processor may determine a position of impact on the impact surface based on the relative magnitudes of the plurality of electrical signals. The disclosed impact targets comprise an opening in the rear surface of the plate that advantageously increases a sensitivity of the vibration sensor to impacts of the impact target with a sports projectile. As a result, the plate can be made thicker to improve the robustness of the impact target to high force impacts. Typically, a thicker plate responds less to a particular impact resulting in reduced sensitivity, particularly at the edges of the impact plate. A relatively thick plate can also be useful in enabling the impact target to house one or feedback components (such as a strip of LEDs) within its thickness. The increased impact sensitivity of the disclosed impact targets allows the use of thick plates that can withstand high impact forces such as a baseball or cricket ball travelling at a velocity of the order of 100 mph, while maintaining sensitivity for low force impacts. Therefore, the disclosed impact targets provide a robust impact target that can withstand high impact force while maintaining a high sensitivity to register weak impact forces and avoid missing low force impacts and the resulting user frustration. In this way, the impact sensor can detect a wide range of impact force. An impact target according to the embodiment of Figure 2 has undergone testing with a cricket ball launched at between 25 mph and 90 mph. The impact target withstood > 10,000 impacts at 90 mph without failure. The impact target also maintained a hit detection rate of > 99% for > 20,000 impacts at 25 mph.

Claims

CLAIMS 1. An impact target for a sports simulator, the impact target comprising: a plate comprising a front surface and a rear surface opposite the front surface, the rear surface comprising an opening; and a vibration sensor fixedly positioned within the opening, the vibration sensor configured to detect an impact of a sports projectile with the impact target.

2. The impact target of claim 1, wherein the opening extends through a thickness of the plate from the rear surface to the front surface.

3. The impact target of claim 2, further comprising a cover plate overlying the opening on the front surface.

4. The impact target of claim 3, wherein the cover plate comprises one or more perforations.

5. The impact target of any of claims 2 to 4, further comprising a cover sheet overlying the front surface of the plate.

6. The impact target of claim 5, comprising an air gap between the cover sheet and the front surface.

7. The impact target of claim 6, comprising a compressible seal arranged to separate the cover sheet from the front surface to provide the air gap.

8. The impact target of any preceding claim wherein the vibration sensor is mechanically mounted on a mount plate and the mount plate is mechanically fixed to the rear surface of the plate.

9. The impact target of claim 8 when dependent on claim 3 or any claim dependent therefrom, wherein the mount plate is mechanically coupled to the cover plate.

10. The impact target of claim 8 or claim 9, further comprising a second compressible seal between the mount plate and the rear surface.

11. The impact target of claim 1, wherein the opening extends partially through a thickness of the plate from the rear surface towards the front surface.

12. The impact target of claim 11, wherein a portion of the plate between the front surface and the opening is perforated.

13. The impact target of claim 11 or claim 12, further comprising a cover sheet overlying the front surface of the plate.

14. The impact target of claim 13 comprising an air gap between the cover sheet and the front surface.

15. The impact target of claim 14 comprising a compressible seal arranged to separate the cover sheet from the front surface to provide the air gap.

16. The impact target of any preceding claim wherein a cross-section of the opening is adapted to conform to a cross-section of the vibration sensor.

17. The impact target of any preceding claim, wherein the vibration sensor comprises a piezo sensor or an accelerometer.

18. The impact target of any preceding claim, wherein: the rear surface further comprises one or more further openings; and the impact target further comprises one or more further vibration sensors respectively positioned in the one or more further openings.

19. The impact target of any preceding claim further comprising a damper for isolating the vibration sensor from ambient vibrations.

20. A sports simulator comprising an impact target according to any preceding claim.