Device for determining an impact property using two acceleration sensors

Abstract

The invention relates to a device (1) that is optimized to save energy and intended to determine an impact property, in particular an impact acceleration, impact speed, impact force or impact technique, comprising a computation unit (4), a first acceleration sensor (2) and at least one second sensor, which is preferably either a second acceleration sensor (3) or a pressure sensor (300) in a fluid-filled body (200), wherein the computation unit (4) is connected to both the first acceleration sensor (2) and the second sensor, wherein the computation unit (4) and / or the second sensor is in the form of a switchable component and is able to be transferred from a first operating mode to a second operating mode, wherein the switchable component has a lower power requirement in the first operating mode than in the second operating mode, and wherein the first acceleration sensor (3) or the second sensor is designed to transfer the switchable component from the first operating mode to the second operating mode when the first acceleration sensor (2) or the second sensor provides measurement values with a predetermined property.

Description

[0001] Device for determining an impact property with two acceleration sensors

[0002] The invention relates to a device for determining a striking characteristic, in particular a striking acceleration, striking speed, (at least a calculation based on an estimate of the "effective" mass of the athlete) striking force or striking technique, comprising a computing unit, a first acceleration sensor and a second acceleration sensor.

[0003] Martial arts typically involve two or more athletes competing in a ring, attempting to strike each other with punches, kicks, or other physical contact. Examples of such martial arts covered by this description include boxing, karate, kickboxing, taekwondo, kung fu, etc.

[0004] For competition purposes, but also for training and other tests, it is desirable to classify a punch or kick or their effect on a body part, e.g., by assigning a punch frequency, acceleration, force, a value derived from the acceleration or force, or a variable combined or derived from an analysis, such as punching technique, to the punch or kick. Various methods are known for measuring acceleration, e.g., by video analysis of the athlete's movement or by an inertial measurement unit (IMU) built into a punching glove. Examples of these include US 2017 / 134712, US 2018 / 001141, US 2012 / 144414, and WO 2019 / 106672.

[0005] In the study "Walilko, TJ, Viano, DC, & Bir, CA (2005). Biomechanics of the head for Olympic boxer punches to the face. British Journal of Sports Medicine, 39(10), 710-719," forces from blows to the head of a dummy were measured (-78 g in a combined direction, e.g., 2 axes). It would be advantageous to obtain measurements that occur in practice to determine correlations with injuries or athlete performance.

[0006] Also known from the prior art is US2011159939A1, which discloses acceleration sensors with a measuring range of up to 8 g. The measured values ​​of the acceleration sensor are evaluated to calculate an impact force. Furthermore, US 2010 / 0144414 A1 teaches that, on the one hand, acceleration sensors with low measuring ranges and high measuring rates and, on the other hand, acceleration sensors with high measuring ranges and low measuring rates can be used simultaneously to determine all acceleration measured values ​​occurring during an impact with sufficient accuracy. On the one hand, however, there is the problem that a high measuring rate is required to measure the impact, especially in the high measuring range, which is not achieved with the proposed solution. On the other hand, there is also the major disadvantage of very high power consumption, since two acceleration sensors are read and evaluated simultaneously.This significantly reduces the operating time of the batting glove. The connected battery must therefore be recharged or replaced with a fully charged one after a short period of time. However, the goal is for the batting glove to be able to be used for at least an entire day of competition—that is, several hours—without the need to change or recharge the battery.

[0007] An obvious solution to this problem is to use a battery with a higher capacity, but this in turn increases the weight of the batting glove and the volume of the measuring unit, which is not desired by the athlete.

[0008] The invention therefore has the object of providing a device for determining an impact property which can record acceleration measurement values ​​over a large measuring range and at the same time can be used over a long operating period and nevertheless has a low volume and weight.

[0009] This object is achieved according to the invention by a device for determining an impact property, in particular an impact acceleration, impact speed, impact force or impact technique, comprising a computing unit, a first acceleration sensor and a second sensor, which is, for example, a second acceleration sensor or a pressure sensor in a fluid-filled body, wherein the computing unit is connected to both the first acceleration sensor and the second sensor, wherein the second sensor and / or the computing unit is designed as a switchable component and can be switched from a first operating mode to a second operating mode, wherein the switchable component has a lower power requirement in the first operating mode than in the second operating mode, and wherein the first acceleration sensor or the second sensor is designed to switch the switchable component from the first operating mode to the second operating mode,if the first acceleration sensor or the second sensor delivers measured values ​​with a predetermined property, which can be given in particular by the acceleration measured values ​​of the first acceleration sensor exceeding a threshold value or by the measured values ​​corresponding to a predetermined curve characteristic. The term "exceed" is understood here, for example, with regard to the absolute values ​​of the measured acceleration per direction x, y, z separately or across all directions together as sqrt(x, 2 +y 2 +z 2 ).

[0010] According to the invention, a device for determining impact force can be operated with at least three components (acceleration sensor, additional sensor, computing unit), wherein this device has a reduced power requirement by embodying at least one of the components as a switchable component and only selectively connecting it. According to the invention, the condition for displacing the switchable component is met by measured values ​​having a predetermined property, e.g., exceeding a threshold value.

[0011] Typically, the device is designed such that the computing unit is the switchable component and is switched to the second operating mode by the second sensor, e.g., a high-acceleration sensor, via an interrupt signal—which is output when a threshold is exceeded. At this time, the computing unit can read an internal memory of a low-acceleration sensor. Thus, the computing unit can receive past data from the low-acceleration sensor and future data from the high-acceleration sensor. However, other variants are also possible, e.g., one acceleration sensor switches the other to the second operating mode. These options are explained in more detail below.

[0012] The device according to the invention enables all measurement ranges to be recorded with the respective acceleration sensor / sensor, while simultaneously requiring low power. According to the invention, the switchable component is thus only activated when there is a high probability of an impact occurring and can then be deactivated again.

[0013] Surprisingly, it was possible to switch on the switchable component “on the fly” during a hit. Due to the short impact duration, this initially seemed counterintuitive, but tests have shown that the components have sufficiently fast reaction times to be switched on “on the fly”. The solution according to the invention can therefore increase the battery life of the device, which is essential if the device is to be operated over a longer period of time - such as an entire competition day. If the solution according to the invention were not used, a larger battery would have to be used to operate a corresponding device over an entire competition day. From an alternative perspective, the invention can therefore also be seen as a weight reduction of the device, since a correspondingly smaller battery can be used.

[0014] The threshold mentioned at the beginning is an acceleration value above which the switchable component(s) should be switched on. As an alternative to a threshold, a predetermined curve characteristic can also be detected, e.g., a sudden increase in the acceleration data, as this can indicate an impact. The recognized curve characteristic has the advantage that the impact can be detected before a high acceleration is reached. Furthermore, an algorithm could be used, whereby an impact can be detected early on from the acceleration data, e.g., using machine learning. The predetermined characteristic is thus a property that can be stored in an algorithm or a machine learning database.

[0015] The computing unit can be implemented as a simple integrated circuit or as a simple logic circuit. Alternatively, it could be a computer with a computer program stored on it. It is particularly advantageous if the computing unit and at least two sensors are installed on a common circuit board, as this means only a single element needs to be attached in or to the device.

[0016] The two operating modes of the switchable component can be implemented in different ways. In a first variant, the switchable component can be switched off in the first operating mode. If the switchable component in this variant has a response time that is too slow, i.e. a time until the switchable component delivers or receives the first measured value in the second operating mode after being switched on, the first operating mode can also be a standby mode. A standby mode is understood to be an operating mode in which the switchable component is energized compared to the switched off variant, but does not output or receive measured values, thereby achieving a faster response time. However, most switchable components have a sufficient response time even when switched off, so that a standby mode does not need to be provided.

[0017] If the switchable component, or one of the switchable components, is the second acceleration sensor or a pressure sensor, this switchable component can deliver a lower rate of measured values ​​per unit of time in the first operating mode than in the second operating mode. In this variant, the response time is extremely short. The first operating mode is used as a de facto standby mode and can also have such a low rate that tracking the impact movement in the first operating mode is not possible.

[0018] It should be emphasized at this point, however, that other variants are also possible. In each case, however, the power consumption of the switchable component should only increase when the respective event (when the threshold is reached, the curve characteristic, etc.) is triggered.

[0019] From the above, it is clear that the primary reduction in power consumption is achieved by extremely selectively connecting the switchable component. A secondary reduction in power consumption can be achieved by switching off the first acceleration sensor or switching it to an operating mode with reduced power consumption when the switchable component is in the second operating mode. In one embodiment, the first acceleration sensor can also be selectively switched off or switched to a standby mode when the second acceleration sensor is already providing measured values.

[0020] The threshold value is particularly important in the inventive solution, as it enables precise adjustment of the switching point from the first operating mode to the second operating mode. The computing unit or the first acceleration sensor could even have a control input via which the threshold value can be adjusted. If, for example, it turns out that the switchable component has an excessively long response time (see above), the threshold value can be lowered, as this extends the time it takes for the first acceleration sensor to reach its maximum measurable acceleration value.

[0021] In general, it is preferable for the threshold value to be below a maximum measurable acceleration value of the first acceleration sensor, rather than exactly at this value. For example, the threshold value can be 50%-95% of the maximum measurable acceleration value of the first acceleration sensor. For example, if the first acceleration sensor has a measurement range of 16 g, the threshold value can be 8 g to 15.2 g. It is understood that the threshold value can also be selected differently depending on the application.

[0022] A threshold value below a maximum measurable acceleration value of the first acceleration sensor has the advantage of allowing a certain reaction time of the second sensor (see above).

[0023] According to the invention, the second sensor is a second acceleration sensor and it is provided that the two acceleration sensors have different measuring ranges, i.e. the second acceleration sensor can be designed to measure higher acceleration values ​​than the first acceleration sensor. In this case, the first acceleration sensor can also be referred to as a low-acceleration sensor and the second acceleration sensor as a high-acceleration sensor. The low-acceleration sensor can have a measuring range of up to 16 g in three orthogonal directions and the high-acceleration sensor can have a measuring range of up to 64 g in three orthogonal directions. However, it would also be possible to use two acceleration sensors which have the same measuring range but, for example, different internal memory sizes or different sampling frequencies.The solution according to the invention is also advantageous in this case.

[0024] It is also advantageous if the first acceleration sensor has an internal memory, which is preferably a FIFO memory. This allows the data stored in the internal memory to be output when the switchable component is switched from the first operating mode to the second operating mode, thus obtaining the measurement data recorded shortly before the impact. The memory size can be configured such that measurement data is stored over a predetermined period of time, e.g., 1 second. Older data can be automatically overwritten.

[0025] Particularly preferably, the computing unit is the switchable component and is switched off in the first operating mode or in a standby mode. This can be combined in particular with the two aforementioned groups of features, in which case the computing unit can be designed to receive the data from the internal memory of the first acceleration sensor after switching from the first operating mode to the second operating mode and, starting from the time of said switching, to receive and store acceleration measurement values ​​from the second acceleration sensor, preferably over a predetermined period of time or until an acceleration threshold value is undershot. After that, all raw measurement data associated with a blow, including that from other sensors, are well-sorted, e.g. in a memory of the computing unit. The computing unit can then check whether it really was a blow (e.g. via a plausibility check) and estimate the duration of the blow, e.g.e.g., using an algorithm or curve functions. Estimating the impact duration is advantageous because it allows for better utilization of the onboard memory. It can also optimize the transfer time of the measurement data to another device.

[0026] As just mentioned, it is therefore also advantageous if the device comprises an additional memory (also called onboard memory) in which the data from the internal memory of the first acceleration sensor and the data received from the second acceleration sensor as well as, if applicable, the measurement data output by other sensors are stored in a linked manner, wherein the onboard memory can be read out via an external interface. The onboard memory can be volatile or non-volatile and can store the measurement data over a long period of time, preferably over an entire day of competition. The onboard memory is also suitable as a buffer for wireless transmission, e.g. via Bluetooth, if data is to be retransmitted at a later time in the event of transmission problems in a live mode (i.e. in a mode in which measurement data is sent immediately).

[0027] Alternatively or in addition to the aforementioned variant, in which the computing unit is the switchable component, the second sensor could also be the switchable component or one of the switchable components. In this case, the second acceleration sensor is preferably switched off in the first operating mode or delivers a lower rate of acceleration measurement values ​​in the first operating mode than in the second operating mode. In these variants, it is particularly preferred if the threshold value is below a maximum measurable acceleration measurement value of the first acceleration sensor. This allows both acceleration sensors to deliver acceleration measurement values ​​simultaneously over a certain period of time, or a response time of the second acceleration sensor can be bridged.

[0028] The aforementioned variant also uses a computing unit (which may be switched to the second operating mode at the same time as the second acceleration sensor), which can evaluate the impact and / or store the measurement data in another memory (onboard memory). In this variant, too, the first acceleration sensor can have an internal memory that can be read by the computing unit. If the computing unit is continuously in operation, it can also continuously receive, evaluate, and store measurement data from the first acceleration sensor (although this is not always advantageous due to the large amount of data and the increased power consumption of the computing unit). In this case, the computing unit could be designed to perform impact detection and only switch the second sensor to the second operating mode if an impact is likely to have occurred.

[0029] In general, it can therefore be said that the device comprises an onboard memory in which the data from the internal memory of the first acceleration sensor and the data received from the second acceleration sensor (from the time the device is switched to the second operating mode) are stored, wherein the onboard memory can be read via an external interface. It is understood that the external interface does not have to be a dedicated interface of the onboard memory. For example, the external interface could be a transceiver connected to the computing unit (e.g., a Bluetooth transceiver, in particular a Bluetooth Low Energy, BLE, transceiver), which is connected to the computing unit, which in turn reads data from the onboard memory.

[0030] Furthermore, the acceleration sensor configured to measure higher acceleration values ​​than the other acceleration sensor preferably has a higher sampling frequency (preferably at least twice as high a sampling frequency) than the other acceleration sensor. This is advantageous because the high-acceleration sensor is intended to measure the rapidly changing and simultaneously high acceleration values ​​or negative acceleration / deceleration values ​​during an impact, and the low-acceleration sensor is intended to measure the acceleration data caused by the athlete or the moving body part prior to the impact and relatively low, i.e., low in terms of the rate of change and the acceleration amplitude. This reduced sampling frequency can achieve a further energy reduction.

[0031] To return the switchable component to its first operating mode, thereby reducing power consumption, various options can be provided. In the simplest case, the measured values ​​from the first acceleration sensor can indicate that the switchable component is no longer needed, at which point it can be returned to its first operating mode.

[0032] The acceleration measurements of the two acceleration sensors serve different purposes. The acceleration measurements of the low-acceleration sensor (usually the first acceleration sensor) are used to track the movement sequence, so that, for example, a striking technique and an average and maximum execution speed can be determined. The acceleration measurements of the high-acceleration sensor (usually the second acceleration sensor), however, serve a different purpose, namely the determination of the braking acceleration, contact time, striking force, and the identification of the target (e.g., punching bag, wall, mitts, body - specifically, the magnitude of the negative acceleration can be used to determine, using statistical methods or machine learning and, if necessary, in conjunction with some other variables, what type of target is being struck). For this purpose, the aforementioned computing unit or another computing unit (such as, for example,A device (e.g., a smartphone) can be configured to calculate a force measurement value from acceleration measurements from the second acceleration sensor (possibly also in combination with measurement data from other sensors) during an impact, together with an estimated or predetermined effective mass or the mass of a target. It is clear that the measured values ​​from the two acceleration sensors could also be fed to different evaluation units, as they serve different purposes.

[0033] Particularly preferably, the device comprises an inertial measuring unit comprising one of the acceleration sensors (usually the low-acceleration sensor) and a yaw rate sensor, wherein the inertial measuring unit is separate from the other acceleration sensor. In other words, the other acceleration sensor is not part of the inertial measuring unit. Inertial measuring units comprising acceleration sensors with low measuring ranges such as up to 8 g or up to 16 g are readily available commercially. If the acceleration sensor of the inertial measuring unit is the switchable component, the entire inertial measuring unit can represent the switchable component. Alternatively, the yaw rate sensor could be permanently in operation, while the acceleration sensor of the inertial measuring unit forms the switchable component.

[0034] In a particularly preferred configuration, the first acceleration sensor is designed to measure acceleration values ​​of up to 16 g (or up to 8 g) in three orthogonal spatial directions, and / or the second acceleration sensor is designed to measure acceleration values ​​of up to 64 g (or up to 100 g or up to 128 g) in three orthogonal spatial directions. However, in particular for the second acceleration sensor, it could also be provided that this acceleration sensor only measures acceleration values ​​along one axis, namely the normal hitting direction (i.e. in a forward direction, viewed with respect to the batting glove). The second acceleration sensor is namely not usually used for hitting tracking. However, measuring the acceleration in three orthogonal spatial directions by the second acceleration sensor is advantageous in order to obtain more precise measurement results.

[0035] Alternatively, the second sensor could also be a pressure sensor, in which case the device comprises a punching glove with a fluid-filled body in which the pressure sensor is located. The concept of the switchable component can also be implemented in this case, so that either the computing unit is switched to the second operating mode when the first acceleration sensor or the pressure sensor provides corresponding measurement data; or the pressure sensor could be switched to the second operating mode when the first acceleration sensor provides corresponding data.

[0036] Advantageous and non-limiting embodiments of the invention set out in the claims are explained in more detail below with reference to the drawings.

[0037] Figure 1 shows a device for determining an impact property in a schematic view with the components located inside the device (in a variant without a pressure sensor).

[0038] Figure 2a shows the device of Figure 1 in a schematic perspective view with components located therein.

[0039] Figure 2b shows a schematic block diagram of selected components of the device.

[0040] Figures 3, 4 and 5 show the acceleration curves occurring during an impact in a device along an x-axis (Figure 3), a y-axis (Figure 4) and a z-axis (Figure 5).

[0041] Figure 6 shows three superimposed acceleration curves and the components for determining the respective acceleration measurements.

[0042] Figure 7 shows the acceleration values ​​measured by a first acceleration sensor.

[0043] Figure 8 shows the acceleration values ​​measured by a second acceleration sensor. Figure 9 shows an embodiment in which a pressure sensor is provided in a punching glove.

[0044] Figure 1 shows a device 1 used to determine an impact characteristic such as impact acceleration, impact speed, impact force, or impact technique. The device 1 can, for example, be a box with a plastic housing 5 containing the electronics described below. The box is designed so small that it can be attached to a body part, in particular the hand, e.g., with dimensions of 4 cm x 3 cm x 1 cm. In the example shown, a bandage 1' is attached to the wrist, which has a receptacle for the device 1. The device 1 is, for example, inserted into a pocket of the bandage 1', and the bandage 1' is then wrapped around the wrist. In the same way, the device 1 could also be attached to the foot or ankle. It goes without saying that the device 1 can also be attached directly to the body (or, for example, to a crash test dummy).

[0045] The device 1 or box described above could also be inserted into a pocket of a punching glove or a protective device such as a foot guard, thus eliminating the need for a bandage 1'. The device 1 could also comprise a punching glove or be another striking element itself, in which the electronics described below are housed. Furthermore, the device could comprise another piece of body protection, such as a head guard, in which the electronics described below are housed and "passively" measure the impact. The device could also be mounted on a punching bag.

[0046] As shown in Figures 2a and 2b, in a first embodiment, the device 1 comprises a first acceleration sensor 2 and a second acceleration sensor 3. The two acceleration sensors 2, 3 typically differ from one another in terms of their measuring range, whereby in this embodiment, the second acceleration sensor 3 can measure higher acceleration values ​​than the first acceleration sensor 2. In other words, the first acceleration sensor 2 has a smaller measuring range than the second acceleration sensor 3. Both acceleration sensors 2, 3 can have the same or different sampling rates (acceleration values ​​per unit time), which can also change depending on the operating state.

[0047] Furthermore, the device 1 comprises a computing unit 4, which is connected to the two acceleration sensors 2, 3. In the illustrated embodiment, the computing unit 4 is located directly next to the acceleration sensors 2, 3, so that the acceleration sensors 2, 3 can be connected to the computing unit 4 via cables or other connections on a circuit board. The computing unit can be, for example, a simple arrangement of decision devices (logic circuit) or a complex system (microcontroller).

[0048] Furthermore, a further evaluation unit 6 can be provided (which can optionally communicate with the computing unit 4 via radio), which calculates and / or stores the acceleration data and / or the impact characteristics determined from the acceleration data, in particular impact acceleration, impact velocity, or impact force. This can be used, for example, for offline training and data looping. The evaluation unit can be located inside or outside the device.

[0049] Furthermore, a battery 7 is located in or connected to the device 1. The battery 7 is connected to both acceleration sensors 2, 3 and to the computing unit 4. It is obvious that the battery 7 should, on the one hand, be light and small enough not to be a hindrance to a user of the device 1, but, on the other hand, should have the longest possible operating time so that the device 1 can be used for as long as possible without recharging or replacing the battery.

[0050] In a preferred variant, to implement the aforementioned design, an electronic circuit board can be provided inside the device 1, on which circuit board, in addition to the aforementioned acceleration sensors 2, 3, other components could be located, e.g., a wireless transmission unit (e.g., for communication between the computing unit 4 and the external evaluation unit 6). Furthermore, the battery 7 is located in the device 1 and is connected to the circuit board and thus to the components located on the circuit board. It is understood that other embodiments are also possible, e.g., if the device 1 comprises a punching glove and a battery 7 can be loosely attached to the punching glove.

[0051] As already mentioned above, it is preferred if the two acceleration sensors 2, 3 and the computing unit 4 (particularly preferably on the common circuit board) and optionally also the battery are located within a plastic housing 5, which can have the shape of a box. Both the first acceleration sensor 2 and the second acceleration sensor 3 are generally designed to record acceleration measurement values ​​in three orthogonal spatial directions x, y, z. Typically, the spatial directions x, y, z of the acceleration sensors 2, 3 are aligned, i.e., one of the spatial directions y points forward on the device 1 (in the normal impact direction), one of the spatial directions x points downwards (i.e., is normal and vertical to the normal impact direction), and the third axis z runs orthogonally to the other spatial directions x, y (i.e.,lies normal and horizontal to the normal impact direction), so that the corresponding acceleration measured values ​​ax, ay, az can be measured. In other embodiments, however, one or both of the acceleration sensors 2, 3 could also only measure the acceleration along one axis, for example if this axis y is aligned along the normal impact direction of the device 1. It should already be noted at this point that it is not relevant with which sign the acceleration is recorded, i.e. whether a negative acceleration or a positive acceleration is measured. This also applies to the terminology "exceeding the threshold value" and "falling below the threshold value", since in this case an absolute value is assumed and it is irrelevant whether the values ​​are measured in the negative or positive domain.However, a different threshold value could be provided in a +x / +y / +z direction than in the opposite -x / -y / -z direction; the threshold values ​​of the 6 individual directions x, y and z can also be selected individually.

[0052] The purpose of device 1 is to record the acceleration occurring during an impact. This typically includes a period before the impact and a period after the impact, i.e., the term "upon impact / impact" or "during impact / impact" encompasses a period surrounding the impact. In particular, the starting acceleration and the deceleration acceleration occurring during an impact are to be measured.

[0053] In this context, Figures 3 to 5 show the acceleration values ​​ax, ay, az occurring during a strike with device 1, where the impact force Fs=2.5 kN and the target was a sandbag. The acceleration is plotted on the vertical axis in units of g, where g=9.81 m / s. 2 A time course is plotted on the horizontal axis, with the impact starting at approximately 0.72 seconds. During the impact for which the acceleration values ​​are shown, device 1 struck a flat surface. The acceleration value ay was measured along the direction of impact, and the acceleration values ​​ax, az were measured in orthogonal directions normal to the direction of impact; see also the coordinate system in Figure 1.

[0054] It is now the object of the invention to record this acceleration curve from Figures 3 to 5 (or at least the acceleration curve in the normal impact direction) as energy-efficiently as possible using the device 1 described above. For this purpose, various embodiments can be used, each of which has in common that a component is designed as a switchable component and is only switched on or operated with an increased power consumption upon detection of a (potential) impact. Generally, the switchable component is switched from a first operating mode to a second operating mode, with the switchable component having a lower power consumption in the first operating mode than in the second operating mode.

[0055] In the first variant, the first acceleration sensor 2 and the second acceleration sensor 3 are permanently in operation. In this embodiment, the computing unit 4 is the switchable component and does not retrieve any measurement data from the sensors in the first operating mode. When the computing unit 4 switches to the second operating mode, it begins to read out the measurement data. The first acceleration sensor 2 has a lower measuring range than the second acceleration sensor 3. In this variant, the first acceleration sensor 2 is intended to record the measurement data “before” the impact (see, for example, Figure 7) and the second acceleration sensor 3 is intended to acquire the measurement data “after” the impact. The computing unit is only intended to be switched on when the impact is detected (usually by the second acceleration sensor 3) at time tO.Figure 6 shows a variant intended for this purpose, in which the three orthogonal acceleration measurement values ​​ax, ay, az, measured over time t, are shown superimposed in this diagram.

[0056] For this purpose, the first acceleration sensor 2 comprises an internal memory 20 for continuously recording data. For example, the acceleration data of a predetermined period of time can be recorded, e.g., the last x seconds, for example, the last 640 ms, which corresponds to a memory requirement of 64 kB. The internal memory 20 can, for example, be designed as a FIFO (First In First Out), which easily makes it possible to always record the last x seconds or minutes. Not shown is that the second acceleration sensor 3 can also have an internal memory, in which, however, measurement data can usually be stored for a shorter period of time than is the case with the aforementioned internal memory 20.

[0057] The second acceleration sensor 3, which can also be referred to as a high-acceleration sensor, has special triggering capabilities, so that it is used to detect the onset of a beat and to switch the computing unit 4 from the sleeping state to the awake state, i.e., from the first operating mode to the second operating mode. The improved triggering capabilities of the second acceleration sensor 3 result, for example, from the larger measuring range and preferably also from a higher sampling frequency, i.e., the output rate of acceleration measurement values, of the second acceleration sensor 3 compared to the first acceleration sensor 2.

[0058] As soon as the second acceleration sensor 3 detects the onset tO of an impact, e.g., when the measured acceleration values ​​exceed a threshold value S, it can wake up the computing unit 4, e.g., by sending an interrupt signal (generally a signal) to it. This puts the computing unit 4 into the second operating mode. Previously, the computing unit's power consumption was low or even nonexistent. As soon as the computing unit 4 is woken up, it receives the data from the internal memory 20 of the first acceleration sensor, ie

[0059] Acceleration measurements from the "past" before the onset of the impact. The internal memory of the second acceleration sensor 3 can also be read by the computing unit 4, e.g., to bridge a reaction time of the computing unit 4.

[0060] Furthermore, the computing unit 4 receives acceleration measurement values ​​from the second acceleration sensor 3 starting from the time tO at which the computing unit 4 was awakened, i.e., was switched to the second operating mode. It can be seen that the computing unit 4 thereby receives acceleration measurement values ​​from the past relative to tO from the first acceleration sensor 2 and acceleration measurement values ​​from the future relative to tO from the second acceleration sensor 3.

[0061] It should be noted that the second acceleration sensor 3 could also have an internal memory, but this is not necessary in the present embodiment. When the computing unit 4 is in the first operating mode, i.e., asleep or switched off, both acceleration sensors 2, 3 are active and buffer measurement data internally without the computing unit 4 retrieving it. As already mentioned, the computing unit 4 reads acceleration measurement values ​​from the second acceleration sensor 3 when the computing unit 4 is in the second operating mode. The computing unit 4 does not have to read any "current" acceleration measurement values ​​from the acceleration sensor 2 and usually does not do so. However, it is preferred if the first acceleration sensor 2 is part of an IMU that also includes a yaw rate sensor.The current measurement data of the yaw rate sensor, which are measured by the sensor after switching to the second operating mode, could also be read by the computing unit 4 after it has been woken up. The yaw rate sensor could also store data in the internal memory 20, which is sent to the computing unit 4 together with the historical data of the first acceleration sensor 2.

[0062] As already explained above, the computing unit 4 can be woken up when the acceleration measurement values ​​of the second acceleration sensor 3 exceed a threshold value. In other variants, the wake-up signal could also be output when a threshold value is exceeded over a predetermined period of time, e.g., when 3 g is exceeded for 20 ms. Alternatively, the second acceleration sensor 3 could also switch to the second operating mode when a predetermined curve characteristic C is detected, as can be seen, for example, in Figure 7. It can be seen that the impact begins at this point, since the acceleration measurement values ​​increase suddenly. The strength of the sudden increase can be defined by the curve characteristic.

[0063] In order to enable even earlier detection of when the second acceleration sensor 3 should switch to the second operating mode, an algorithm, in particular a machine learning algorithm, can also be used which detects a predetermined property of the acceleration measurement values.

[0064] In a second variant with a switchable component, one of the two acceleration sensors 2, 3 can be switched from a first operating mode to a second operating mode. This is particularly advantageous when the first acceleration sensor 2 is generally operated continuously and the second acceleration sensor 3, which has a higher measuring range than the first acceleration sensor 2, represents the switchable component.

[0065] In this variant, the first operating mode is, in the simplest case, a switched-off state and the second operating mode is a switched-on state, in which the second acceleration sensor 3 records acceleration measurement values ​​or at least buffers them in an internal memory. In a further variant, the second acceleration sensor 3 could also record acceleration measurement values ​​at a first rate in the first operating mode and at a second rate in the second operating mode, wherein the first rate is lower than the second rate. The second rate is, in particular, a maximum rate of acceleration measurement values ​​per unit of time, e.g., 1000 Hz. The first rate is a predetermined percentage thereof, e.g., 10%, in which case the first rate would be 100 Hz. It goes without saying that other rates can also be selected.

[0066] In the specific example now described with reference to Figures 7 and 8, the first acceleration sensor 2 was designed to measure accelerations of up to 16 g, which is represented in Figures 7 and 8 by the measuring range M, and the second acceleration sensor 3 was designed to measure accelerations of up to 64 g.

[0067] Figure 7 shows the measured values ​​output by the first acceleration sensor 2 when an acceleration curve as shown in Figure 4 is present. All measured values ​​within the measuring range M of 16 g are output correctly. However, as soon as the acceleration exceeds 16 g, it can no longer be measured by the first acceleration sensor 2, so it either continues to output the maximum acceleration measured value of 16 g (although the actual acceleration value is higher), or an error signal is output.

[0068] The computing unit 4 (which in this variant is either operated continuously or is only switched on when the first acceleration sensor detects a starting acceleration for a later impact) can either control the first acceleration sensor 2 in such a way that it is switched on for the entire measurement duration, or can switch it off (or reduce its power) when the second acceleration sensor 3 is in the second operating mode.

[0069] The computing unit 4 (or the first acceleration sensor 2) now controls the second acceleration sensor 3 in such a way that it is not switched on all the time or running at full power (ie that the second acceleration sensor 3 is not in the first operating mode all the time), but the second acceleration sensor 3 is only selectively switched to the second operating mode, as can be seen in Figure 8.

[0070] Specifically, the second acceleration sensor 3 is switched to the second operating mode when the acceleration measurement values ​​of the first acceleration sensor 2 reach a threshold value S. The threshold value S is generally within the measuring range M of the first acceleration sensor 2, i.e., below the absolute value of the maximum measurable acceleration of the first acceleration sensor 2. In the example in Figure 8, it can be seen that the first threshold value S was 14 g, i.e., as soon as the first acceleration sensor 2 measured 14 g for the first time, the second acceleration sensor 3 was switched to the second operating mode (in the example shown, the second acceleration sensor 3 immediately delivered measured values, although this is not mandatory; there could even be a certain measurement gap, which preferably ends before a maximum value). Before this, the second acceleration sensor 3 was in the first operating mode, i.e.,was switched off or operating at reduced power. In other cases, however, the threshold value S could also coincide with the limit of the measuring range M, i.e., with the absolute value of the maximum measurable acceleration of the first acceleration sensor 2, so that the threshold value S in this example would be 16 g. However, a threshold value S that lies within the measuring range M of the first acceleration sensor 2 has the advantage, among other things, that the measurement series of the two acceleration sensors 2, 3 can overlap, making them easier to correlate with each other.

[0071] Figure 8 shows that the second acceleration sensor 3 was switched on at the threshold value S (here 14 g). This enables the second acceleration sensor 3 to precisely record, in particular, the range from 16 g to 64 g (or -16 g to -64 g), which lies outside the measuring range M of the first acceleration sensor 2. However, it is also clear that the second acceleration sensor 3 does not have to be switched off immediately when the threshold value S is again undershot, but can continue measuring for some time thereafter. This is particularly relevant because it is expected that, after an initial maximum value, further (positive and negative) maximum values ​​will occur during an impact.

[0072] In the variant of Figure 8, the second acceleration sensor 3 is switched back to the first operating mode if the second acceleration sensor 3 measures only a slightly changing acceleration over a predetermined time window Z. Alternatively, the second acceleration sensor 3 could be switched back to the first operating mode after a threshold value R (which can be selected differently than the threshold value S) has not been exceeded for a predetermined time, e.g., 1 second, 2 seconds, or even 10 seconds. In a further variant, the second acceleration sensor 3 could switch back to the first operating mode after a predetermined time after being switched from the first to the second operating mode, e.g., after 1 second, 2 seconds, or even 10 seconds.In a further embodiment, the second acceleration sensor 3 could be switched back to the first operating mode when the threshold value S (or another threshold value within the measuring range M) is again undershot.

[0073] In the examples above, the first acceleration sensor 2 had a measuring range M of 16 g and the second acceleration sensor 2 had a measuring range of 64 g (at this point, it should be noted that the term "measurement range of xg" is understood to mean that acceleration values ​​from -xg to +xg can be measured). However, it is understood that the acceleration sensors 2, 3 could also have other measuring ranges, e.g., the first acceleration sensor 2 could have a measuring range of 8 g to 32 g and the second acceleration sensor 3 could have a measuring range of more than 16 g or more than 32 g, e.g., a measuring range of substantially 32 g or 128 g.

[0074] In this embodiment, too, the first acceleration sensor 2 can be part of an inertial measurement unit (IMU), which, in addition to the acceleration measurement values, can also determine rotation rates, preferably about three essentially orthogonal spatial directions. The rotation rates are preferably also output when the second acceleration sensor 3 is in the second operating mode. This enables precise tracking of the movement sequence and thus the type of impact can be determined solely from the data of this inertial measurement unit. The first acceleration sensor 2 is thus, for example, continuously in operation and tracks the impact itself, and the second acceleration sensor 3 is only selectively switched on when the threshold value is reached in order to determine the precise impact behavior of the device 1.

[0075] The acceleration values ​​measured by the acceleration sensor 2, 3 with the higher measuring range can be used in particular to calculate a force value (impact force), which can be carried out by the aforementioned computing unit 4 or another computing unit (which is located outside the device 1 and is, for example, a stationary computer). To calculate the impact force F, the acceleration values ​​a measured during an impact of the device 1 can be multiplied by an estimated or predetermined effective mass m. The impact force F is calculated from F=m*a, where a is the measured (peak) acceleration and m is the aforementioned effective mass. A pulse p can also be determined as p=fF*dt.

[0076] An impact speed v can also be determined by measuring the

[0077] Acceleration a is integrated. From the impact velocity v, a kinetic energy Ekin of the impact can be calculated as Ekin=m*v 2 / 2. Furthermore, a lay length can be determined, which can also be linked to the above-mentioned lay properties if necessary. These calculations can be used for all embodiments described herein.

[0078] Typically, the accelerations measured by the first acceleration sensor 2 are used to calculate the impact type or impact speed, and the accelerations measured by the second acceleration sensor 3 are used to calculate the impact force. These calculations can be performed by the computing unit 4 or an external computing unit.

[0079] In a further variant, the device can comprise a pressure sensor 300 in addition to or alternatively to the second acceleration sensor, as schematically illustrated in Figure 9. Figure 9 shows a punching glove 100 comprising a fluid-filled body 200. The fluid-filled body 200 consists of a deformable shell filled with a fluid, in particular a gas such as air or a liquid. Also located inside the fluid-filled body 200 is a pressure sensor 300, which measures the hydrostatic pressure within the fluid-filled body 200 and transmits it to the computing unit 4, which can be located inside or outside the punching glove 1. The computing unit 4 can convert pressure values ​​measured by the pressure sensor 300 into force values, so that the striking force of the punching glove 1 can be determined. Furthermore, this embodiment variant comprises (at least) the first acceleration sensor 2.

[0080] The embodiment of Figure 9 can be operated either analogously to the first variant mentioned above or to the second variant mentioned above. In other words, firstly, the first acceleration sensor 2 and the pressure sensor 300 can be operated continuously. As soon as the first acceleration sensor 2 detects the onset of an impact, as previously via a threshold comparison, a curve characteristic, etc., the computing unit 4 is switched from the first operating mode to the second operating mode. As soon as the computing unit 4 is in the second operating mode, it reads the internal memory 20 of the first acceleration sensor 2 and then cyclically determines the measurement data from the pressure sensor in order to determine the impact force. Secondly, the pressure sensor 300 could be designed as a switchable component. As soon as the first acceleration sensor 2 detects the onset of an impact (via a threshold value, curve characteristic, etc.), the pressure sensor or the computing unit 4 switches the pressure sensor 300 from the first operating mode to the second operating mode, so that from this point on, data can be read from it, from which the impact force can be determined. All of the aforementioned options can therefore also be implemented in the variant shown in Figure 9.

[0081] In the embodiment of Figure 9, it could also be provided that two acceleration sensors 2, 3 are provided, which are generally operated as in the first variant. As soon as the computing unit 4 has been switched to the second operating mode, it now reads the current measurement data from both the second acceleration sensor 3 and the pressure sensor 300.

[0082] It is understood that by means of the described device 1, further functions known per se can also be implemented, such as determining the force of gravity by means of the acceleration in the x-direction measured in the rest state and adjusting the acceleration during a blow or impact for the force of gravity.

Claims

Claims:

1. A device (1) for determining an impact characteristic, in particular an impact acceleration, impact speed, impact force, or impact technique, comprising a computing unit (4), a first acceleration sensor (2), and at least one second sensor, which is a second acceleration sensor (3), wherein the second acceleration sensor (3) is designed to measure higher acceleration values ​​than the first acceleration sensor (2), characterized in that the computing unit (4) is connected to both the first acceleration sensor (2) and the second sensor, wherein the computing unit (4) and / or the second sensor is designed as a switchable component and can be switched from a first operating mode to a second operating mode, wherein the switchable component has a lower power requirement in the first operating mode than in the second operating mode, and wherein the first acceleration sensor (3) or the second sensor is designed toto switch the switchable component from the first operating mode to the second operating mode when the first acceleration sensor (2) or the second sensor detects measured values ​​with a predetermined property, which can be given in particular by the acceleration measured values ​​of the first acceleration sensor (2) or the second acceleration sensor exceeding a threshold value (S) or by the measured values ​​corresponding to a predetermined curve characteristic., 2. Device (1) according to claim 1, wherein the first acceleration sensor (2) has an internal memory (20) and is designed to output the data stored in the internal memory (20) when the switchable component is switched from the first operating mode to the second operating mode.

3. Device (1) according to one of the preceding claims, wherein the computing unit (4) is the switchable component and is switched off or in a standby mode in the first operating mode.

4. Device (1) according to claims 2 and 3, wherein the computing unit (4) is designed to receive the data of the internal memory (20) of the first acceleration sensor (2) after the shift from the first operating mode to the second operating mode and to receive acceleration measurement values ​​of the second acceleration sensor (3) starting from the time (tO) of said shift, preferably over a predetermined period of time or until an acceleration threshold is undercut.

5. Device (1) according to one of the preceding claims, wherein the second acceleration sensor (3) is designed as a switchable component and can optionally be switched to the second operating mode simultaneously with the computing unit (4).

6. Device (1) according to claim 5, wherein the threshold value (S) is below a maximum measurable acceleration measurement value of the first acceleration sensor (2).

7. Device (1) according to one of the preceding claims, further comprising an onboard memory in which the data of the internal memory of the first acceleration sensor and the data received from the second acceleration sensor are stored, wherein the onboard memory is readable via an external interface.

8. Device according to one of the preceding claims, wherein the acceleration sensor which is designed to measure higher acceleration values ​​than the other acceleration sensor has a higher sampling frequency than the other acceleration sensor.

9. Device (1) according to one of the preceding claims, wherein the first acceleration sensor (2) is designed to measure acceleration measured values ​​of up to 16 g in three mutually orthogonal spatial directions, and / or wherein the second acceleration sensor (3) is designed to measure acceleration measured values ​​of up to 64 g in three mutually orthogonal spatial directions.

10. Device (1) according to one of the preceding claims, wherein said curve characteristic is a sudden increase in the measured acceleration values.

11. Device (1) according to one of the preceding claims, wherein the first acceleration sensor (2) or the second acceleration sensor (3) is part of an inertial measuring unit with a rotation rate sensor for movement tracking.

12. Device (1) according to one of the preceding claims, comprising a plastic housing (5) in which the two acceleration sensors (2, 3) and the computing unit (4) are enclosed, wherein the device preferably further comprises a bandage in which the plastic housing (5) can be accommodated, wherein the bandage preferably has a pocket in which the plastic housing (5) can be accommodated.

13. Device (1) according to one of claims 1 to 11, comprising a striking glove (100) or a body protection part such as a head guard.

14. The device according to claim 13, wherein the striking glove (100) comprises the fluid-filled body (200) in which a pressure sensor (300) is arranged.

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