Non-contact sensor for measuring an energy FLUX in a metallic magnetic structure

Abstract

The present invention is in the field of a measuring system for measuring physical properties of a magnetic metallic structure, in particular for measuring an energy flux in said magnetic structure, a method wherein said sensor system is used, such as for driving piles, and a computer program for driving said piles and / or for carrying out said method.

Description

[0001] NON-CONTACT SENSOR FOR MEASURING AN ENERGY FLUX IN A METALLIC MAG- NETIC STRUCTURE

[0002] FIELD OF THE INVENTION

[0003] The present invention is in the field of a measuring system for measuring physical properties of a magnetic metallic structure, in particular for measuring an energy flux in said magnetic struc- ture, a method wherein said sensor system is used, such as for driving piles, and a computer pro- gram for driving said piles and / or for carrying out said method.

[0004] RELATED APPLICATIONS

[0005] The present application claims the benefit of priority from Dutch Patent Application NL2037579, filed on April 29, 2024, in the name of Technische Universiteit Delft., The Netherlands.

[0006] The entire contents of the above-referenced applications and of all priority docu- ments referenced in the Application Data Sheet filed herewith are hereby incorporated by reference for all purposes

[0007] BACKGROUND OF THE INVENTION

[0008] In mechanics, strain is defined as a relative deformation, compared to a reference position configuration. Typically, strain therefore has a dimension of a length ratio (m / m), and are usually expressed as a decimal fraction or a percentage. Mathematically, strain is typically expressed as a tensor. Normal strain and shear strain may be considered, within a deforming physical body. A state of strain at a material point of the physical body may be defined as the totality of all the changes in length of material lines, the normal strain, which pass through that point and also the totality of all the changes in the angle between pairs of lines initially perpendicular to each other, the shear strain, radiating from this point. If there is an increase in length of the material line, the normal strain is called tensile strain; otherwise, if there is reduction or compression in the length of the material line, it is called compressive strain.

[0009] Determining strain typically requires a sensor or the like in contact with the object to be sensed. Currently, mechanical strain levels and structural velocity of steel structures are measured with sensors (strain gauges and / or accelerometers) that are in physical contact with the structure. Quite often this is not possible, such as when a measurement is performed on an object with varying strain, having impact on the object to be measured, and therefore distorting a measurement. Some- times it is too cumbersome or practically difficult or impossible to make contact between the sensor and the object to be sensed. For instance, when driving piles, an impact of a hammer driving the pile into the soil, makes contact measurements rather difficult due to the high forces acting on the meas- uring equipment. Also, it is often too time-consuming to add a sensor or the like. Furthermore, the sensors are prone to being damaged when they are exposed to high stress levels, e.g. during an im- pact.

[0010] US2002 / 148298 Al recites a system for the determination of pile parameters includes at least one structure for measuring pile data. The structure for measuring pile data is disposed within a measurement range from a pile. A wireless transmitter is communicably connected to the structure for measuring pile data, the wireless transmitter for transmitting the pile data to at least one re- motely located receiver. Pile data is preferably encoded in the transmitted data signal. The remotely located receiver is communicably connected to a device for determining at least one pile parameter from the pile measurement data. US 2022 / 196526 Al recites a non-contact system for monitoring a metallic magnetic structure under dynamic load for detecting an impact induced propagating stress wave, and a method of determining strain in a metallic magnetic structure under dynamic load, such as a tube-like structure, such as a monopile for a wind turbine. US 6,098,447 A recites an attenua- tion circuit for a pile driving force measurement device is disclosed. The attenuation circuit allows for measurements to be made of the force being applied to a driven pile at a reduced voltage com- patible with a voltage sensitive measurement device, such as a personal computer. The forces meas- ured create measurable electrical impulses via magnetostriction. The attenuation circuit conditions the measured impulses so that no separate electrical power circuit or battery is required to power the sensor. At the same time the attenuation circuit protects the measurement device from voltages which might be overly high and damage the equipment. Gomez et al.

[0011] (doi: 10.1016 / J.JSV.2022.117299) recite that the energy flux in a pile modeled as an elastic shell, is studied theoretically and experimentally. Based on this analysis, a new procedure is proposed to quantify the pile installation efficiency. This procedure is of importance for vibratory installation of the foundations of offshore wind turbines and it is believed to be the first procedure that relies di- rectly on the energy propagating down the pile rather than the energy supplied by the vibratory shaker.

[0012] The present invention relates to an improved method of measuring, in particular of an en- ergy flux, which overcomes one or more of the above disadvantages, without jeopardizing function- ality and advantages.

[0013] SUMMARY OF THE INVENTION

[0014] The present invention relates in a first aspect to a non-contact sensor system. The in- vention relates to a sensor system, which comprises as (sub)-sensors a magnetic field sensor to measure the change of the magnetic field of a metallic (magnetic) structure to infer the strain state, and a motion sensor, such as an optical sensor, to measure the velocity of the surface of the metallic structure. The term “metallic” is used to indicate a material property of the structure. In view of the magnetic field sensor, the metal is a metal having measurable magnetic properties, or comprises said metal, or is a combination of such metals. In princi- ple also paramagnetic metals could be measured, but typically ferromagnetic materials, such as iron, cobalt, nickel, gadolinium, and their alloys, anti -ferromagnetic materials, such as chromium, ferrimagnetic materials, such as ferrites, in particular wherein the magnetic mate- rial selected from Group 3-12, Period 4-6 elements, such as Fe, Co, Ni, and some rare earth metals, and comprising such a magnetic material, such as FePd, FeCo and FePt, and combi- nations thereof, may be considered. A structure is a 3D-item. Within the structure an energy flux is expected, e.g. to a hammer driving a pile into the soil. This energy flux is sensed by the two non-contact sensors, at a specific relatively small region of the structure. The motion sensor is configured to sense motion at a surface or of the surface of the structure. The mag- netic field sensor senses the magnetic field, in particular a variation of the magnetic field, in said structure, which is found to be proportional to the strain in the structure. A multiplica- tion of these two quantities (strain times velocity) is found to provide the flux of mechanical energy in the structure, at the point of measurement. A primary field of application is pile driving, where the energy flux is considered quite important to determine an efficiency of an installation procedure. Due to the non-contact nature of the present sensor system, it is easy to employ, e.g. it can be “integrated” into an impact hammer. Contrary to other non-contact systems to monitor e.g. pile driving, the present sensor system does not require any prepara- tion of the structure, e.g. the pile. Other non-contact methods are in principle possible; how- ever, these require advance measures to be taken, such as visual patterns to be applied to the structure's surface, or attachment of reflectors for the used laser light. Moreover, in the pre- sent invention strain and velocity are both measured, whereas in other, non-contact, methods only deformation is measured. The strain is typically induced from the measured variation of the magnetic field of the pile. The motion, e.g. velocity, of the pile's surface may be meas- ured by Laser Doppler Velocimetry or by Surface Length Velocimetry; both methods require no visual patterns to be added to the structure's surface. The motion sensor preferably has a relatively high sampling rate, in the order of kHz or higher. In an exemplary embodiment the present sensor system comprises of a magnetic field sensor for measuring (radial and vertical field components), a motion sensor, such as an optical velocity sensor, and typically a data acquisition device, a controller, and a processing unit, which later two may be combined.

[0015] Multiple sensors could be used in a ring provided around the pile to improve the accuracy by combining the data from multiple positions of around the circumference of the pile. Addi- tional sensors might be added to correct for potential disturbing factors. For instance, a tem- perature sensor to correct for drift in the magnetic field sensor caused by temperature; a (MEMS-type) gyroscope to track the rotation of the sensor box and hammer; and a linear ac- celerometer to track the vibrations of the sensor. Using primary data (strain and velocity) obtained from the sensors, the flow of energy from the hammer to the soil can be monitored. This can be used in a feedback loop to optimize such a pile driving process, by changing the hammer settings based on the measured energy flux.

[0016] The present sensor system may replace contact -based sensors, by a non-contact meas- urement, i.e. a magnetic field measurement for the strain and an optical sensor for the veloc- ity. There is no need to physically attach this new sensor to the structure, resulting in easier deployment, reusability of the same sensor, improvement safety for personnel, reduction the risk of damage to the sensor. The non-contact nature of the chosen measurement principles is considered an essential element of this invention. The present sensor system can be used in an offshore environment, in which conventional sensors are very rarely used, due to the high cost related to preparing such a measurement. It may also be used for monitoring of magnetic metallic structures, such as bridges, railways, etc. Albeit the present sensor-system might slightly more costly, the reusability thereof makes the OPEX much lower.

[0017] In a first aspect, the present invention relates to a non-contact sensor system 3 com- prising at least one magnetic field sensor 5 for measuring variation in magnetic flux density, in particular for measuring radial and / or axial magnetic field components (Brand Bz), more in particular for measuring a variation in said magnetic field components, the magnetic field sensor providing magnetic flux density output, at least one motion sensor (6) for measuring motion, in particular motion selected from at least one of motion vzin a direction parallel to the magnetic field component Bz, and from motion vtin a direction tangential to the mag- netic field component Bz, the motion sensor providing motion output, wherein the magnetic field sensor and the motion sensor have an at least partially overlapping field of view, that is, sensors substantially overlap in terms of a part of an object to be measured, and in terms of a time domain in which said measurement takes please, the time domain being substan- tially the same, that is, starting at a (same) starting point in time and ending at a (same) end point in time, so 50-100% overlap is typically applicable, in particular 90-100% overlap, at least one controller configured for controlling the magnetic field sensor and the motion sen- sor, in particular for controlling said sensors such that measuring strain and measuring mo- tion occur in the same time domain, as mentioned above, a data acquisition system (DAQ) (7) receiving input from the magnetic field sensor and from the motion sensor, and a data processor for processing the input of the sensors and for providing a flux of mechanical en- ergy based on said input, in particular wherein the processor is configured to obtaining elas- tic strain from variation in magnetic flux density and motion. The DAQ, and the at least one controller may be combined, such as wherein the DAQ (also) is the at least one controller; optionally also the data processor may be combined, such as also into the DAQ. In other words, one processor, acting as at least one controller, a DAQ, and a data processor could be sufficient. The energy flux is expressed in W / m2. The elastic strain is determined using the data obtained by the magnetic field sensor. The mechanical energy flux S is then found to be the product of the strain tensor and velocity vector:

[0018] For impact pile driving, the expression for the energy flux much simpler, since most terms in the expression above can be neglected. This results in the following expression for the mechanical energy flux along the pile’s axis: '

[0019] For other pile driving methods, e.g. the GDP vibratory shaker, less terms from the full expression can be neglected. Hence, the strain and velocity must be determined in more di- rection. In a second aspect the present invention relates to a method for driving a pile, com- prising providing the pile, positioning the present sensor system of in proximity of the pile, driving the pile into a soil using a pile driver, in particular using a driver selected from an impact hammer, a weight, and a driver providing a combination of vertical and torsional vi- bration (GDP), and measuring a flux of mechanical energy through the pile to the soil. For a gentle driver of Piles (GDP) reference can be made to WO 2021 / 040523 A1, of the present applicant. The impact of the GDP on the pile can be measured with the present sensor sys- tem. The same applies for an impact of a hammer and or weight providing impact energy to the pile.

[0020] In a third aspect the present invention relates to a computer program or integrated cir- cuit comprising instructions, in particular wherein the computer program is loaded on a pro- cessor or in a memory, the instructions causing the computer to carry out (or conduct) the following: instructing a pile driver to drive the said pile into a soil, in particular an impact hammer, and instructing the present sensor system to measure a flux of mechanical energy through the pile to the soil.

[0021] Thereby the present invention provides a solution to one or more of the above-men- tioned problems.

[0022] Advantages of the present description are detailed throughout the description. Refer- ences to the figures are not limiting, and are only intended to guide the person skilled in the art through details of the present invention.

[0023] DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention relates in a first aspect to the non-contact sensor system accord- ing to claim 1.

[0025] In an exemplary embodiment of the present sensor system the at least one motion sensor is selected from at least one of a non-contact electromagnetic field sensor, an ultra- sonic sensor, and an optical sensor, such as using IR or laser light, more in particular at least one motion sensor configured to detect motion vzof a said magnetic material in at least the direction parallel to the central vertical axis of the said magnetic material, in par- ticular an optical sensor, more in particular an optical velocity sensor.

[0026] In an exemplary embodiment of the present sensor system the at least one motion sensor has a sampling rate of > 500 Hz, in particular > 1000 Hz, more in particular > 5000 Hz, such as > 10 kHz.

[0027] In an exemplary embodiment of the present sensor system the at least one optical sensor is selected from an optical Doppler sensor, in particular a Laser Doppler Veloci- metry sensor, from a high-speed optical sensor comprising a multitude of pixels, from a surface length sensor, in particular a Surface Length Velocimetry sensor, more in particular wherein the optical sensor is configured to provide light and to sense reflected light. This method is found to work by reflecting a laser beam from the surface. It requires no prepara- tion, such as visual marking, or reflectors of the surface of an object to be measured, which is needed in other methods that monitor pile driving. This optical sensor in particular works by analysing pictures at very high speeds, such as > 103frames / sec. It typically uses a large number of pixels, per frame, such as > 106pixels. Even then, it still does not require visual markers on the surface.

[0028] In an exemplary embodiment of the present sensor system the strain and the motion are measured in a said magnetic material, in particular wherein the said magnetic material is selected from a driving pile, a support pile, a windmill pile, an infrastructural element, in particular a bridge, a railway or part thereof. In other words, as long as the material to be measured is somewhat magnetic, the present system can be used to measure a variation of magnetic field and motion thereof. The system therefore is broadly applicable.

[0029] In an exemplary embodiment of the present sensor system the sensor system is config- ured for measuring at a distance of the said magnetic material, such as in a flying object.

[0030] In an exemplary embodiment of the present sensor system the sensor system is pro- vided in a housing.

[0031] In an exemplary embodiment of the present sensor system the sensor system is config- ured to receive electrical power.

[0032] In an exemplary embodiment of the present sensor system the sensor system is config- ured to transmit data.

[0033] In an exemplary embodiment of the present sensor system the sensor system is config- ured to receive data.

[0034] In an exemplary embodiment of the present sensor system the sensor system com- prises a transceiver.

[0035] In an exemplary embodiment of the present sensor system the sensor system com- prises a positioner for maintaining the sensor system in a location in space, in particular wherein the positioner is a flying object, such as a drone.

[0036] In an exemplary embodiment of the present sensor system the sensor system com- prises a positioning sensor configured for maintaining the sensor “in place”, that is, in sub- stantially the same spatial location, that might be considered also relative to an object to be measured. The positioning sensor may control a positioner, such as a step-motor, correcting for small deviation by moving the sensor system (back) to it’s “original” position, that it, a position where it originally at the start was located.

[0037] In an exemplary embodiment the present sensor system the comprises at least one fur- ther sensor, wherein the at least one further sensor is selected from a temperature sensor for correcting drift in any other sensor, an orientation sensor, and angular velocity sensor, con- figured for monitoring relative rotation of the sensor system and / or pile driver, in particular a gyroscope (such as a MEMS), an accelerometer configured for monitoring vibrations of the sensor system, such as a linear accelerometer, in particular wherein the at least one fur- ther sensor is integrated in the sensor system.

[0038] In an exemplary embodiment the present sensor system the comprises at least one controller, wherein the at least one controller is configured to process the motion sensor output and the magnetic field output, and configured to control energy provided to the said magnetic material, in particular to control impact energy, and / or to provide feedforward and / or feedback, and / or wherein the at least one controller, the data acquisition system, and data processor are provided as one or more processors.

[0039] In an exemplary embodiment of the present method the measured mechanical energy flux is used to control the energy provided by the pile driver to the pile, in particular to in- crease the energy provided, to decrease the energy provided, or to maintain the energy level provided. This may be achieved by an increase / decrease of pile driver hammer fall dis- tance; or likewise, by an increase / decrease in driving frequency / amplitude of a pile driver.

[0040] In an exemplary embodiment of the present method the energy / time is controlled, in particular by increasing a number of quantized energy provisions per unit time, by decreas- ing a number of quantized energy provisions per unit time, or to maintain a number of quantized energy provisions per unit time at a present level. That is, a driving frequency of a hammer of weight is adapted accordingly.

[0041] In an exemplary embodiment the present computer program further comprises instruc- tions for instruction the pile driver to control the impact energy provided by the pile driver to the pile based on the measured energy flux, in particular to increase the impact energy, to decrease the impact energy, or to maintain the impact energy.

[0042] The invention is further detailed by the accompanying figures and examples, which are exemplary and explanatory of nature and are not limiting the scope of the invention. To the person skilled in the art, it may be clear that many variants, being obvious or not, may be conceivable falling within the scope of protection, defined by the present claims.

[0043] SUMMARY OF FIGURES

[0044] Figure 1-4 show details of the present invention.

[0045] DETAILED DESCRIPTION OF FIGURES

[0046] 1 steel pile

[0047] 2 hydraulic impact hammer

[0048] 3 non-contact sensor

[0049] 4 anvil

[0050] 5 conventional sensor (for reference measurement)

[0051] 6 motion sensor & magnetic field sensor

[0052] 7 data acquisition system (DAQ)

[0053] 8 processor

[0054] 9 controller

[0055] Bzmagnetic field strength in vertical direction Brmagnetic field strength in radial direction

[0056] Figure 1 shows a pile 1 and the present non-contact sensor system 6 comprising a motion sen- sor and a magnetic field sensor.

[0057] Fig. 2 schematically show a steel pile 1, a hydraulic impact hammer 2, an anvil 4, a non-con- tact sensor 3, and magnetic and motion vectors enforced by the impact hammer.

[0058] Fig. 3 shows schematics of the present non-contact sensor system with, integrated in one unit, a CPU 8, a controller 9, and a DAQ 7, a conventional contact sensor for reference measurements 5, and further the sensor box 6 comprising magnetic field sensor and optical velocity sensor, as well as vectors being measured. A field of view is schematically indicated, as well as the part of the pile surface which is measured by the respective sensors.

[0059] Fig. 4 shows a practical implementation of the sensor box.

[0060] The figures are further detailed in the description of the experiments below.

[0061] EXAMPLES / EXPERIMENTS

[0062] An exemplary sensor system was designed. A working prototype is attached to an impact hammer to finalize the hammer integration. Then, this configuration is tested onshore and finally offshore.

[0063] The present system was placed at a distance of 20-50 cm from the pile to be driven. The magnetic field flux could be measured accurately, at a field of view location. Also, the motion at field of view is measured accurately. Based thereon the flux of mechanical energy at the field of view location is determined, typically with an accuracy of better than ±2% relative, e.g. better than ±1% relative. Measurements are performed in a rather continuous manner, e.g. a sample rate of 1Hz-50 kHz, or, sampling is aligned in time with the impact of the hammer, that is, at each impact time, a measurement is performed. A standard computer, including dedicated software, is used to calculate the flux of mechanical energy. Based thereon, if con- sidered appropriate, the impact of the hammer is adjusted. For instance, the number of quan- tized energy provisions per unit time is increased, or likewise the energy o the hammer. As a result, the energy consumption is reduced with 5-25%, compared to standard operation. A similar result is obtained when driving a pile with a pile shaker.

[0064] Further, the driving frequency of the impact hammer was increased and decreased. Also, the energy impact per blow was increased and decreased. A clear distinction in mechanical energy flux between the different set-ups was found. Based on the mechanical energy fluxes for the different set-ups optimal settings were determined, e.g. in impact energy, and driving frequency.

[0065] The invention although described in detailed explanatory context may be best under- stood in conjunction with the accompanying figures.

[0066] It should be appreciated that for commercial application it may be preferable to use one or more variations of the present system, which would similar be to the ones disclosed in the present application and are within the spirit of the invention.

Claims

AMENDED CLAIMS received by the International Bureau on 29 August 2025 (29.08.2025).

1. A non-contact sensor system (3) comprisingAt least one magnetic field sensor (6) for measuring variation in magnetic flux density, in particular for measuring radial and / or axial magnetic field components (Bzand Br), more in particular for measuring a variation in said magnetic field components to infer the strain state, the magnetic field sensor providing magnetic flux density output,At least one motion sensor (6) for measuring motion, in particular motion selected from at least one of motion Vzin a direction parallel to the magnetic field component Bz, and from motion Vt in a direction tangential to the magnetic field component Bz, the motion sensor providing motion output,Wherein the magnetic field sensor and the motion sensor have an at least partially overlapping field of view,At least one controller configured for controlling the magnetic field sensor and the motion sensor, in particular for controlling said sensors such that measuring strain and measuring motion occur in the same time domain,A data acquisition system (DAQ) (7) receiving input from the magnetic field sensor and from the motion sensor, andA data processor for processing the input of the sensors and for providing a flux of mechanical energy based on said input, in particular wherein the processor is configured to obtaining elastic strain from variation in magnetic flux density and motion.

2. The sensor system according to claim 1, wherein the at least one motion sensor is selected from at least one of a non-contact electromagnetic field sensor, an ultrasonic sensor, and an optical sensor, such as using IR or laser light, more in particular at least one motion sensor configured to detect motion Vzof a said magnetic material in at least the direction parallel to the central vertical axis of the said magnetic material, in particular an optical sensor, more in particular an optical velocity sensor, and / orWherein the at least one motion sensor has a sampling rate of > 500 Hz, in particular > 1000 Hz, more in particular > 5000 Hz, such as > 10 kHz.

3. The sensor system according to claim 2, wherein the at least one optical sensor is selected from an optical Doppler sensor, in particular a Laser Doppler Velocimetry sensor, from a high speed optical sensor comprising a multitude of pixels, from a surface length sensor, in particular a Surface Length Velocimetry sensor, more in particular wherein the optical sensor is configured to provide light and to sense reflected light4. The sensor system according to any of claims 1-3, wherein the strain and the motion aremeasured in a said magnetic material, in particular wherein the said magnetic material is selected from a driving pile, a support pile, a windmill pile, an infrastructural element, in particular a bridge, a railway or part thereof.

5. The sensor system according to any of claims 1-4, wherein the sensor system is configured for measuring at a distance of the said magnetic material, such as in a flying object, and / or wherein the sensor system is provided in a housing.

6. The sensor system according to any of claims 1-5, wherein the sensor system is configured to receive electrical power, and / orWherein the sensor system is configured to transmit data, and / orWherein the sensor system is configured to receive data, and / orWherein the sensor system comprises a transceiver, and / orWherein the sensor system comprises a positioner for maintaining the sensor system in a location in space, in particular wherein the positioner is a flying object, such as a drone.

7. The sensor system according to any of claims 1-6, wherein the sensor system comprises a positioning sensor configured for maintaining the sensor in place.

8. The sensor system according to any of claims 1-7, comprising at least one further sensor, wherein the at least one further sensor is selected from a temperature sensor for correcting drift in any other sensor, an orientation sensor, and angular velocity sensor, configured for monitoring relative rotation of the sensor system and / or pile driver, in particular a gyroscope (such as a MEMS), an accelerometer configured for monitoring vibrations of the sensor system, such as a linear accelerometer, in particular wherein the at least one further sensor is integrated in the sensor system.

9. The sensor system according to any of claims 1-8, comprising at least one controller, wherein the at least one controller is configured to process the motion sensor output and the magnetic field output, and configured to control energy provided to the said magnetic material, in particular to control impact energy, and / or to provide feedforward and / or feedback, and / or wherein the at least one controller, the data acquisition system, and data processor are provided as one or more processors.

10. The sensor system according to any of claims 1-9, comprising a receiver, the receiverconfigured to receive output of the at least one magnetic sensor and the at least one motion sensor, and optionally the DAQ and the data processor, in particular wherein the receiver is ring-shaped, wherein the ring-shape is configured to at least partially surround a said magnetic structure to be measured.

11. A method for driving a pile, comprisingProviding the pile,Positioning the sensor system of any of claims 1-10 in proximity of the pile, Driving the pile into a soil using a pile driver, in particular using a driver selected from an impact hammer, a weight, and a driver providing a combination of vertical and torsional vibration (GDP), andMeasuring a flux of mechanical energy through the pile to the soil.

12. The method according to claim 11, wherein the measured mechanical energy flux is used to control the energy provided by the pile driver to the pile, in particular to increase the energy provided, to decrease the energy provided, or to maintain the energy level provided .

13. The method according to any of claims 11 or 12, wherein the energy / time is controlled, in particular by increasing a number of quantized energy provisions per unit time, by decreasing a number of quantized energy provisions per unit time, or to maintain a number of quantized energy provisions per unit time at a present level.

14. Computer program or integrated circuit comprising instructions, in particular wherein the computer program is loaded on a processor or in a memory, the instructions causing the computer to carry out the following: instructing a pile driver to drive the said pile into a soil, in particular an impact hammer, and instructing the sensor system according to any of claims 1-10 to measure a flux of mechanical energy through the pile to the soil.

15. Computer program according to claim 14, further comprising instructions forInstructing the pile driver to control the impact energy provided by the pile driver to the pile based on the measured energy flux, in particular to increase the impact energy, to decrease the impact energy, or to maintain the impact energy.

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