Method and device for lifting a non-gaseous object in a gaseous environment

Abstract

The invention relates to a method for lifting a non-gaseous object (6) in a gaseous environment against an external force acting on the object (6), for example gravity, in which method a standing sound wave field is generated, by means of a sound-emitting device, between the sound-emitting device and a sound wave-emitting surface. The sound wave field forms a plurality of minimal regions between the sound-emitting device and the surface. In the regions, the sound wave field generates a sound radiation force (Fz) which acts, in an environment of a minimal region, on the object (6) in the direction of the particular minimal region so that the object (6) can be retained in the particular minimal region. According to the invention, in an object deflection step (10), the sound wave field generated by the sound-emitting device is modulated such that the object (6) is moved in the sound wave field from a first minimal region towards a second minimal region which is adjacent to the first minimal region in the opposite direction to the external force.

Description

[0001] Method and device for lifting a non-gaseous

[0002] Object in a gaseous environment

[0003] The invention relates to a method for lifting a non-gaseous object in a gaseous environment against an external force acting on the object, wherein a standing sound wave field is generated by means of a sound emission device with at least one sound generator between the sound emission device and a surface radiating sound waves, which field forms a plurality of minimal regions between the sound emission device and the surface, in which minimal regions the standing sound wave field generates a sound radiation force which acts on the object in the vicinity of a minimal region in the direction of the minimal region in question, so that the object is retained in an equilibrium position in this minimal region when the sound radiation force is equal to the external force.The invention also relates to a device for lifting a non-gaseous object in a gaseous environment against an external force acting on the object, the device comprising a control device and a sound emission device with at least one sound generator, the sound emission device being able to be operated with the control device in such a way that a standing sound wave field can be generated between the sound emission device and a surface emitting sound waves, which forms a plurality of minimal regions between the sound emission device and the surface, in which minimal regions the sound wave field generates a sound radiation force which acts on the object in the vicinity of a minimal region in the direction of the minimal region in question, so that the object is retained in an equilibrium position in this minimal region when the sound radiation force is equal to the external force.

[0004] Various methods are known from practice with which an object, which may consist of liquid or solid material or a combination thereof, can be lifted, for example against a weight, without solid body contact with the object in question being necessary. The lifting of such an object against an external force caused by the weight on the object, also known as levitation, can be achieved, for example, with the help of an air flow flowing around the object. It is also known that an object can be displaced by electrostatic or magnetic forces and displaced against a weight acting on the object in question and can be lifted, for example, from a support surface.

[0005] In acoustic levitation, the object is displaced by a sound radiation force caused by a sound emission produced by a sound emission device with at least one sound generator. A standing sound wave field is generated between the sound generator and a surface emitting sound waves, in which a minimal region forms in which the object is held suspended by the sound radiation force acting on the object. By spatially displacing the sound generator relative to the surface emitting sound waves, the standing sound wave field can be changed and the object held suspended in the minimal region can be displaced.

[0006] The standing sound wave field can be generated between a sound generator and a surface arranged at a distance therefrom, which reflects the sound waves emitted by the sound generator in the direction of the surface in the direction of the sound generator, so that a standing sound wave field is generated by the superposition of the sound waves emitted by the sound generator and those reflected by the surface. It is also known that the standing sound wave field can be generated by a first sound generator and a second sound generator, wherein the second sound generator forms the sound wave-emitting surface which radiates sound waves in the direction of the first sound generator. The standing sound wave field is then formed by the superposition of the sound waves emitted by the first sound generator and the second sound generator.

[0007] Acoustic levitation has the advantage over many other methods that objects can be lifted and kept floating in a sound wave field regardless of their electrical or magnetic properties.

[0008] In acoustic levitation, the knowledge can be used that in the immediate vicinity of a sound-emitting sound generator, also referred to as the near field, a sound wave field with a minimal region is formed in which the sound radiation force exerted on an object is lower than in an environment of the minimal region, whereby the sound radiation force in an environment of the minimal region exerts a force effect of the sound radiation force directed in the direction of the minimal region.If the sound wave field generates a sound radiation force whose effect on an object is greater than the effect of an external force such as weight or an electric field, the object is retained in the minimal region at a short distance from the sound emitting device and also against the external force in this minimal region, so that the object levitates without any solid-body contact at a short distance from the sound emitting device.

[0009] The formation of the minimal region within the near field of the sound emission device depends on the propagation of the sound waves in the immediate vicinity of the sound emission device, which in turn can depend on many factors such as the density and temperature of the gaseous environment. The near field is usually referred to as an area in the immediate vicinity of the sound generator that extends up to a distance of one wavelength of the sound waves propagating from the sound generator in the gaseous environment. An ultrasonic transducer is usually used as the sound generator; this converts electrical control signals into ultrasonic emissions, whereby the ultrasonic emissions usually have a frequency of 20 kilohertz or more.When the ultrasonic transducer is surrounded by air at standard conditions , the sound waves propagate at a speed of sound of about 343 m / s and at 20 kilohertz with a wavelength of about 1.7 cm , so that the near field usually extends to a distance of about 1.7 cm around the sound generator and the minimum region within the near field has a significantly smaller distance of less than a few millimeters from the sound generator .

[0010] As soon as an object whose dimensions are smaller than the wavelength of the emitted sound waves is arranged in the minimal region that is in the near field of the sound emission device, the sound emission device can be displaced in the gaseous environment and the object floating in this minimal region can be carried along because the sound wave field causes sound radiation forces directed in the direction of the minimal region to act on the object and hold it back in the minimal region. In this way, for example, using an ultrasonic transducer arranged and operated on a robot arm, an object that has been arranged in its minimal region in the near field can be carried and displaced by the sound emission device in almost any direction within a spatial detection range of the robot arm.If necessary, the object can also be placed on surfaces that are within the spatial detection range of the robot arm after the ultrasonic transducer has been switched off.

[0011] However, it is considered a disadvantage that the object cannot be easily lifted from a surface by the sound radiation pressure and transferred into the minimal region in the near field of the sound wave field generated by the sound emission device, but must be grasped by other means such as tweezers and introduced into the minimal region in the near field of the sound wave field.

[0012] Practical experiments as well as theoretical simulations have shown that in a standing sound wave field which is generated between a sound-emitting acoustic emission device and a surface which reflects the sound emitted by the acoustic emission device, several minimal regions can form between the acoustic emission device and the surface, the distance of which from the acoustic emission device can be a multiple of the wavelength of the sound waves emitted by the acoustic emission device, so that at least one of these minimal regions is located outside the near field and thus in a far field away from the acoustic emission device.Investigations have shown that with the help of such a standing sound wave field it is possible to lift an object from a surface into a first minimal region of the standing sound wave field which, of the several minimal regions, has the shortest distance from the surface on which the object was arranged before being lifted by the standing sound wave field. In this way it is possible to lift suitably shaped small objects made of solid or liquid material from a surface and let them levitate without solid contact with the object in question being necessary. However, it is considered a disadvantage that the object can only be lifted into a first minimal region which is closest to the surface and is usually located in the near field of the standing sound wave field.For practical application it is considered a further disadvantage that for a longer lasting levitation of the object in this first minimal region a sound wave field is required that is constant over the entire time period, whereby a displacement of the object relative to the surface is considerably restricted.

[0013] It is therefore considered an object of the present invention to design a method for lifting a non-gaseous object in a gaseous environment against an external force acting on the object in such a way that more possibilities for displacing the object in the gaseous environment are made possible.

[0014] This object is achieved according to the invention in that, in an object raising step, the sound wave field generated by the sound emission device is modulated such that the object is displaced beyond the first minimum region in the direction of a second minimum region which is arranged adjacent to the first minimum region opposite to the direction of the external force.

[0015] Before the object elevation step, the object is held in an equilibrium position by the superposition of the sound radiation force generated in the sound wave field and the external force acting on the object. The standing sound wave field can be generated either between a sound generator and a surface that reflects the sound waves emitted by this sound generator and thus emits sound waves, or between a first sound generator and a second sound generator, with the second sound generator then forming the sound wave-emitting surface.

[0016] This equilibrium position is not located at a center point of the first minimal region in which no sound radiation force is exerted on the object, but rather at a distance from the center point in the direction of the external force. In this equilibrium position, the sound radiation force generated in the standing sound wave field exerts a force on the object in the direction of the center point of the first minimal region that is equal to and opposite to the force exerted on the object by the external force, so that in the equilibrium position the force of the external force is compensated by the force of the sound radiation force. The greater the external force, the greater the distance of the equilibrium position from the center point of the first minimal region.

[0017] If, in the object elevation step, the sound wave field generated by the sound emission device is modulated such that the sound radiation force increases and becomes greater than the external force, a displacement force resulting from the superposition of the larger sound radiation force and the smaller external force is exerted on the object. This displacement force is directed toward the center of the first minimal region and opposite to the external force. Therefore, in the object elevation step, the object is accelerated and displaced toward the center of the first minimal region by the stronger sound radiation force.By means of a suitable modulation of the sound emission during the object lifting step, the object can be accelerated from the deflection position towards the centre of the first minimal region with a sufficiently large sound radiation force so strongly that the object is displaced through the first minimal region and up to the second minimal region in order to reach a new equilibrium position there and to be held back in this new equilibrium position in the area of ​​the second minimal region by the superposition of the sound radiation force and the external force.

[0018] During such a displacement of the object from the equilibrium position toward the second minimal region, the sound wave field must be capable of being modulated such that the maximum sound radiation force that can be exerted on the object in the sound wave field against the external force is greater than the sound radiation force that can retain the object in the equilibrium position. The maximum sound radiation force that can be exerted on the object in the sound wave field against the external force must therefore also be greater than the force of the external force.By appropriate modulation of the sound wave field, the object can then initially be held in the equilibrium position in the first minimal region by a first acoustic radiation force, then transferred to a second minimal region by a larger second acoustic radiation force, and finally held in a new equilibrium position in the second minimal region by a third acoustic radiation force. With a constant external force or at least of equal magnitude in both minimal regions, the third acoustic radiation force essentially corresponds to the first acoustic radiation force.

[0019] It is intended that the sound wave field forms a first minimum region and a second minimum region before the object elevation step, that the object is displaced in the object elevation step from the first minimum region towards the second minimum region, and that the object is influenced by the sound radiation force (F z) of the sound wave field is retained in the second minimum region of the sound wave field. The sound wave field before and after the object elevation step is essentially identical, with any possible impairment of the sound wave field by the object being neglected. In particular, all parameters relevant for sound generation for the operation of the sound emission device with at least one sound generator as well as for the arrangement of the sound emission device and a surface emitting sound waves relative to one another can be specified identically before and after the object elevation step.

[0020] These considerations also envisage that the sound wave field forms the same minimal regions after the object elevation step as before the object elevation step. For the displacement of the object in the object elevation step, it is not necessary for the position of the minimal regions formed by the sound wave field to be changed relative to the environment or relative to one another during or after the object elevation step. The positions of the minimal regions can be maintained unchanged and consistent before, during, and after the displacement of the object, as long as the sound wave field is generated with the sound emission device.

[0021] It can further be provided that the minimum regions of the sound wave field are formed outside a closed resonance chamber. It is neither necessary for the formation of minimum regions of the standing sound wave field between the sound emission device and the surface radiating sound waves nor for the displacement of the object in the object lifting step for the object or the relevant minimum regions to be located within a resonance chamber. In contrast, it is regarded as a significant advantage of the method according to the invention that the sound wave field with the minimum regions and in particular the object held suspended therein and displaceable with an object lifting step can be arranged outside a closed resonance chamber and thus almost arbitrarily in space, and that the object can be displaced almost arbitrarily.In addition, without the use of a resonance chamber, it is possible for the object to be held and moved in a spatial environment that is advantageous for practical applications where restriction to the interior of a resonance chamber would usually be disruptive or make the application impossible.

[0022] According to a particularly advantageous embodiment of the inventive concept, it can be provided that in an object deflection step preceding the object lifting step, the sound wave field generated by the sound emission device is modulated such that the sound radiation force acting on the object against the external force is reduced and the object is displaced in the sound wave field from the equilibrium position in the first minimum region in the direction of the external force acting on the object.In the object deflection step, by means of a suitable modulation of the sound wave field, for example a reduction of the intensity of the sound emission, the object is displaced from the original equilibrium position into a deflection position further away from the center of the first minimal region in the direction of the external force effect by the force acting on the object, which is no longer completely compensated by the modulated sound wave field in the vicinity of the first minimal region.

[0023] If the sound wave field is generated or modulated after the object deflection step in the previously predetermined manner with which the object was previously held in the equilibrium position, then a sound radiation force is already exerted on the object in the deflection position, which displaces the object from the deflection position towards the equilibrium position. This effect of the sound radiation force therefore already causes a forced movement of the object from the deflection position in the direction desired in the object lifting step, namely towards the second minimum region. If the object is held in the equilibrium position with a first sound radiation force and is then displaced into the deflection position by the object deflection step, the first sound radiation force can already cause an acceleration and displacement of the object in the direction of the second minimum region.

[0024] By deflecting the object in the object deflection step, it can be achieved that, with the exertion of a sound radiation force which previously held the object in the equilibrium position in the first minimal region, the object is accelerated and displaced from the deflection position beyond the equilibrium position in the first minimal region. By a suitably predetermined and induced deflection of the object in the object deflection step, it can also be achieved that, with the exertion of a sound radiation force which previously held the object in the equilibrium position in the first minimal region, the object is accelerated and displaced from the deflection position not only in the direction of the second minimal region, but into the second minimal region.In this case, it is not necessary that the sound wave field can be modulated in such a way that a maximum sound radiation force is significantly larger than the sound radiation force with which the object can be held in the equilibrium position in the first minimal region or in the second minimal region.

[0025] By repeatedly performing an object lifting step and, if necessary, a preceding object deflection step, the object can be displaced successively from the first minimal region into the second minimal region and then into a third and, if necessary, further minimal region following in this direction. In this way, the arrangement of the object within the various

[0026] Minimal regions within the standing sound wave field can be specified almost arbitrarily and thus also, for example, a distance of the object from a surface which is exposed to sound from the sound generator and limits the standing sound wave field.

[0027] The method according to the invention can be illustrated by an example in which a spherical solid object is first lifted against the force of gravity from a surface into a first minimal region formed in a standing sound wave field between a sound-emitting sound generator and the surface. This first minimal region is outside the near field of the sound generator and has the shortest distance from the surface of the several minimal regions formed within the standing sound wave field.As soon as the sound emission generates a sufficiently large force effect of the sound radiation force, which is greater than that on the spherical solid object, the solid object is lifted from the surface and displaced into an equilibrium position in the area of ​​the first minimal region, in which the sound radiation force acting from the surface in the direction of the first minimal region compensates the weight force acting towards the surface.

[0028] In the object deflection step, the sound wave field generated by the sound emission device is modulated or the intensity of the sound emission is reduced in such a way that the sound radiation force acting on the spherical solid object is reduced and the spherical solid object is displaced slightly further towards the surface, or is deflected slightly from the equilibrium position by the force of gravity and displaced into a deflected position. Subsequently, in the object lifting step, the sound intensity and thus the sound radiation force acting on the solid object is significantly increased, whereby the sound radiation force acts on the solid object in the direction of the first minimal region and accelerates the solid object in the direction of the first minimal region and thereby displaces it.By suitably specifying the modulation of the sound wave field that takes place in the object deflection step and in the object elevation step, it is possible to displace the solid-state object in the object elevation step beyond the first minimal region in the direction of a second minimal region that, viewed from the surface, is located behind the first minimal region and is therefore at a greater distance from the surface. In this way, the spherical object, starting from an equilibrium position in the first minimal region, can first be displaced into the deflection position and then into a new equilibrium position in the second minimal region that is at a greater distance from the surface, so that the spherical solid-state object is lifted further from the surface and is held back at a greater distance from the surface in the standing sound wave field between the sound generator and the surface.hovers .

[0029] The surface is expediently aligned and the sound generator is arranged and aligned relative to the surface in such a way that several minimal regions form between the sound generator and the surface along a straight line running parallel to the direction of the weight force and perpendicular to the surface. The displacements of the object during the object deflection step and during the subsequent object lifting step then occur parallel or exactly opposite to the direction of the weight force acting on the object, and the resulting displacements of the object occur along the straight line and thus along the course of the minimal regions within the standing sound wave field.

[0030] However, it is fundamentally possible that the course of the minimal regions does not have to be parallel to the direction of the weight force or another external force acting on the object, but can have an acute angle of, for example, up to 5 ° or 10 ° or more to the direction of the weight force, as long as it can be guaranteed that when the object is displaced by the modulation of the standing sound wave field, the force exerted by the sound radiation force in the vicinity of the first minimal region accelerates and displaces the object against the weight force in the direction of the second minimal region in such a way that the object can reach a new equilibrium position in the vicinity of the second minimal region and be held there.

[0031] According to a particularly advantageous embodiment of the inventive concept, it is provided that in an object bridging step, the sound wave field generated by the sound emission device is modulated such that, during a displacement of the object, a sound radiation force counteracting the displacement of the object in the direction of the second minimal region is reduced. In this way, with a lower force effect or acceleration of the object in the object lifting step, the object can be displaced with the sound radiation force exerted on the object in the object lifting step into an area surrounding the second minimal region, in which the sound radiation force generated by the sound wave field acts on the object in the direction of the second minimal region.In the object raising step, for example, the intensity of the standing sound wave field can be increased and the object can be accelerated from the deflection position in the direction of the first minimum region until the object moves into the minimum region, in order to then reduce the intensity of the standing sound wave field significantly in the object bridging step or to suspend the sound emission until the object has been displaced from the first minimum region to beyond an area with an increasing sound radiation force of the standing sound wave field upon sound emission and is located in the catchment area of ​​the force effect around the second minimum region, which is exerted on the object by the superposition of the sound radiation force generated during sound emission in a standing sound wave field and the external force, for example the force of gravity.

[0032] In this way, the force required to move the object from the first minimal region into the second minimal region can be reduced during the object lifting step. This also means that the object deflection step can be carried out more briefly and the displacement of the object from the equilibrium position into the deflection position carried out before the object lifting step can be smaller, or the distance of the deflection position from the equilibrium position can be smaller than without an object bridging step carried out during the object lifting step. Consequently, less energy and time is required to move the object against the force of the external force from the first minimal region into the second minimal region than is necessary without the object bridging step.

[0033] According to an optional embodiment of the inventive concept, it can be provided that in an object bridging step the sound wave field generated by the sound emission device is modulated, if necessary several times, in such a way that a sound radiation force counteracting the displacement of the object in the direction of the second minimal region is reduced, so that the object is displaced with the sound radiation force exerted on the object in the object raising step into an environment of a third minimal region arranged behind the first minimal region in the direction of the second minimal region, in which the sound radiation force generated by the sound wave field acts on the object in the direction of the third minimal region.In this way, with a single object lifting step, the object can be accelerated from a deflection position in the first minimal region through a clever modulation of the sound wave field and the sound radiation force exerted on the object, first in the direction of the second minimal region and then displaced beyond the second minimal region into a third minimal region lying behind it in this direction. In a sequence of minimal regions within the standing sound wave field, the third minimal region can either be the minimal region immediately following the second minimal region or another minimal region which is spaced several minimal regions apart from the second minimal region in the standing sound wave field.

[0034] In the object bridging step, a temporal sequence of changed modulations of the sound emission can be carried out, for example, to first accelerate the object with an increased sound radiation force starting from the deflection position in the first minimal region in the direction of the first and the second minimal region behind it in this direction, then during the displacement beyond the first minimal region with a reduced sound radiation force to hinder the displacement from the first minimal region into the catchment area of ​​the second minimal region as little as possible, in order to then support the approach to the second minimal region again by increasing the sound radiation force again and to accelerate the object additionally.By alternately increasing and reducing the force of sound radiation, the object can be accelerated several times by the sound emission, and in the areas where the force of sound radiation counteracts the movement of the object, the force of sound radiation can be reduced in order to enable uninterrupted displacement of the object across several minimal regions. The modulation of the sound emissions and thus of the force of sound radiation of the standing sound wave field can be determined in advance as a function of the force acting on the object by the external force, and can be brought about by suitable control of the sound emission device. It can also be provided that, for example, parameters for a position and / or a displacement of the object are recorded with the aid of sensors or optical monitoring devices, and that the operation of the sound emission device is controlled as a function of the parameters recorded.

[0035] It can further be provided that the object is not only displaced in a controlled manner against the external force and, for example, lifted in a gravitational field, but that the object can also be displaced in a controlled manner in a direction predetermined by the external force from a minimal region into a neighboring minimal region in the standing sound wave field. According to one embodiment of the inventive concept, it is therefore provided that in an object lowering step, the sound wave field generated by the sound emission device is modulated such that the object is displaced by the action of the external force from an initial minimal region into a target minimal region, which, starting from the initial minimal region, is arranged in the sound wave field in a direction predetermined by the external force.In this way, by appropriately specifying object raising steps and object lowering steps, an object can be successively displaced into any desired sequence of minimal regions within the sound wave field generated by the sound emission device.

[0036] Furthermore, it can optionally also be provided that in an object depositing step, the sound wave field generated by the sound emission device is modulated such that the object is displaced onto the surface. The object can therefore, starting from a first minimal region, be displaced back and forth almost arbitrarily within the standing sound wave field between different minimal regions and then deposited onto the surface from the minimal regions of the sound wave field. A suitably shaped object, for example a spherical solid object or a drop of liquid, can also be lifted from the surface in an object picking step and displaced into a first minimal region.This makes complex displacement processes possible, particularly for suitably designed objects, so that such an object can be picked up from a surface solely by the action of the sound radiation force and against an external force, moved back and forth between different minimal regions of the standing sound wave field and then deposited back on the surface.

[0037] The modulation of the sound wave field required for the displacement of the object can be achieved in various ways. A particularly simple and efficient possibility is to achieve the modulation of the sound wave field in the object deflection step and / or in the object elevation step and / or in the object bridging step by switching the sound emission of the sound emission device on or off. Only two different operating states of the sound emission device need to be specified: the switched-on operating state and the switched-off operating state. This allows the structural design of the sound emission device and its control to be implemented simply, reliably, and cost-effectively.Such a modulation, which only requires the acoustic emission device to be switched on, can also be used to perform an object bridging step, an object lowering step, or an object setting-down step. For reliable object relocation, the duration and sequence of the two different operating states, or the switched-on and switched-off operating states, are crucial and should be able to be specified as precisely as possible.

[0038] It can also be provided that in the object deflection step and / or in the object raising step and / or in the object bridging step the modulation of the sound wave field is brought about by a suitable change in the sound emission of the sound emission device and / or by a suitable change in a distance and / or an alignment between the sound emission device and the surface. A change in the force effect of the sound radiation force on the object can also be brought about, for example, by a change in the intensity of the sound emission. In this way the sound radiation force caused by the sound emission, which acts on the object, can be varied as desired between a maximum sound radiation force and a low or switched off sound radiation force and can be specified for the desired displacement of the object.

[0039] It is also possible that, for example, by changing the frequency of the emitted sound waves or by changing the distance or orientation of the sound emitting device relative to the surface, the arrangement of the minimal regions within the standing sound wave field is changed and thereby the force effect of the sound radiation force on the object which is located in a given position within the sound wave field is changed.However, it can also be provided and advantageous for various applications that in the object deflection step and / or in the object elevation step and / or in the object bridging step the arrangement of the minimal regions within the standing sound wave field is not changed by the modulation of the sound wave field, so that in particular there is no change in the frequency of the emitted sound waves and also no change in the distance or the orientation of the sound emission device relative to the surface.

[0040] It is also possible for a suitable modulation of the sound wave field to be brought about by changing the properties of sound propagation in the gaseous medium. For example, the arrangement of the minimal regions within the standing sound wave field can be brought about by a suitable change in the temperature or the density or pressure of the gaseous medium. Furthermore, the resulting force acting on the object can also be influenced by a possible change in the external force. If the external force is generated, for example, by an electric field acting on an electrically charged object, a change in the electric field can influence the external force and, with unchanged sound emission, a displacement of the object within the sound wave field can be brought about.If necessary, additional external forces can be generated and exerted on the object. For example, an electrically charged object can be lifted by a suitable sound emission against the weight force exerted by the gravitational field and then displaced by an additionally generated electric field. The additionally generated electric field can cause a force to act in a direction that is not necessarily parallel to the force of the gravitational field. In this way, very complex motion sequences can be realized with suitable objects without the need for solid-state contact with the object.

[0041] Advantageously, it can optionally be provided that in the object deflection step, a modulation of the sound wave field is carried out by superimposing an object selection frequency predetermined as a function of the object, such that the modulated sound wave field excites the object to a periodic oscillation around the equilibrium position in a minimum region. During such a deflection of the object from the equilibrium position, either the sound radiation force or the external force predominates, so that the object is accelerated back towards the equilibrium position. By continuously modulating the sound wave field by superimposing the suitably predetermined object selection frequency, an oscillating movement of the object around its equilibrium position can be excited, so that an amplitude of the periodically oscillating movement of the object gradually increases.The appropriate object selection frequency for this also depends on the external force acting on the object and can vary for different objects. If the external force acting on the object is gravitational force, the object selection frequency depends on the object's own weight or mass.

[0042] If two different objects with different weights are located in two different minimal regions within the standing sound wave field, suitable modulation of the sound wave field with an object selection frequency suitable for one of the two objects can cause only the object in question to be deflected into a periodic oscillation around its equilibrium position. The other object, whose weight does not match the object selection frequency, is also constantly accelerated by the modulated sound wave field, but no periodic oscillation of the other object can develop, so that the other object does not perform a comparable, and in particular, no periodic oscillation around its equilibrium position in the other minimal region.The continuous excitation of the two objects with the standing sound wave field modulated in a suitable manner with the object selection frequency can be carried out until the object, which periodically oscillates around its equilibrium position, shifts into a suitable deflection position, from which this object can be accelerated and shifted with the object lifting step from the deflection position in the first minimal region into a neighboring second minimal region.The second object, which is initially not located in the same first minimal region as the first object, is not significantly displaced during the continuous excitation with the standing sound wave field modulated with the object selection frequency and in particular not simultaneously displaced into a comparable deflection position, so that the second object is not displaced out of its minimal region in the object elevation step and in particular is not displaced into another minimal region.

[0043] In this way, it is possible to first keep two different objects suspended in their respective equilibrium positions in two adjacent minimal regions within the standing sound wave field, then to excite only one of the two objects to a periodic oscillation up to a deflection position in the object deflection step, and then to displace only the object displaced into the deflection position into the adjacent minimal region in the object lifting step, in which the other object is located the entire time. The two objects can therefore initially be located separately from one another in the standing sound wave field and, for example, be manipulated or displaced therein, in order to then be brought together and combined in a single minimal region using a suitable object deflection step and a subsequent object lifting step.

[0044] According to an advantageous embodiment of the inventive concept, it can be provided that in an object translation step the sound emission device and the sound wave-emitting surface are displaced relative to one another, while a standing sound wave field is generated between the sound emission device and the sound wave-emitting surface, such that an object located in a minimal region is displaced relative to the surface in a direction parallel to the surface. In this way, an object can be displaced parallel to a surface at a substantially constant distance from this surface. In combination with object raising steps and object lowering steps, it is possible with object translation steps, for example, to lift the object from a first region on a surface, to displace it laterally into a second region of a surface and to set it down there.The surface can be an area of ​​a workplace in a laboratory or in a production facility, so that with the method according to the invention objects can be moved and manipulated within the workplace without any solid contact with the objects in question. This is particularly advantageous if any contamination of the objects is to be avoided, which can inevitably occur, for example, when the objects come into solid contact with a manipulation device. The surface does not have to be a completely flat surface. For example, concave or pot-shaped depressions can be formed in the surface to promote the arrangement and a desired separation of individual objects in these depressions.It has been found that suitably designed depressions in the surface can also promote the lifting of an object arranged in the depression from the surface solely through the effect of the sound radiation force. It has also been found that, depending on the particular sound wave field generated, a three-dimensional structuring of the surface can be specified or designed in such a way that the sound wave field is only insignificantly changed and only in an area close to the surface, while minimal regions within the sound wave field that are located at a greater distance from the surface are hardly affected, or in any case not significantly affected.

[0045] Optionally, the sound-wave-emitting surface can be formed by a second sound-emitting device with at least one second sound generator, and a first sound-emitting device with at least one first sound generator can be operated in such a way that the standing sound wave field is formed between the first sound-emitting device and the second sound-emitting device. For many applications, it is sufficient and advantageous if the standing sound wave field is generated between a sound-emitting device and a surface that merely reflects the sound.However, it can also be provided that the standing sound wave field is generated between two sound emission devices that are arranged and aligned at a distance from one another and are operated in such a way that a standing sound wave field is formed between the two sound emission devices arranged opposite one another. Two sound emission devices arranged opposite one another can, for example, be arranged and operated on a robot arm so that an object can be held in a minimal region in a standing sound wave field that is generated between the two sound emission devices, and the two sound emission devices with the standing sound wave field and the object arranged and held therein can be displaced as desired with the aid of the robot arm.

[0046] The object can also be transferred back and forth between a first standing sound wave field, generated by a single sound-emitting device and a sound-reflecting surface, and a second standing sound wave field, generated between two opposing sound-emitting devices. This allows for very complex manipulations of the object without requiring contact between the object and a solid body.

[0047] The invention also relates to a device for lifting a non-gaseous object in a gaseous environment against an external force acting on the object, the device comprising a control device and a sound emission device with at least one sound generator, the sound emission device being able to be operated with the control device in such a way that a standing sound wave field can be generated between the sound emission device and a surface emitting sound waves, which forms a plurality of minimal regions between the sound emission device and the surface, in which minimal regions the sound wave field generates a sound radiation force which acts on the object in the vicinity of a minimal region in the direction of the minimal region in question, so that the object is retained in a minimal region if the sound radiation force is greater than the external force.

[0048] According to the invention, the control device for controlling the sound emission that can be generated by the sound emission device is designed and configured in such a way that, in a subsequent object lifting step, the sound wave field generated by the sound emission device can be modulated in such a way that the object is displaced beyond the first minimum region in the direction of a second minimum region that is arranged adjacent to the first minimum region opposite to the direction of the external force.

[0049] In a particularly advantageous manner, it is optionally provided that the control device for controlling the sound emission that can be generated with the sound emission device is also designed and configured in such a way that, in an object deflection step, the sound wave field generated with the sound emission device can be modulated in such a way that the sound radiation force acting on the object against the external force is reduced and the object is displaced in the sound wave field from a first minimum region in the direction of the external force acting on the object.

[0050] With a device designed in this way for lifting a non-gaseous object in a gaseous environment against an external force acting on the object, many steps of the method described above in many variants can be carried out. In this way, an object can be displaced almost arbitrarily within a standing sound wave field and can be arranged and held at various distances from a sound generator used to generate the standing sound wave field.

[0051] Furthermore, it can optionally be provided that the control device for controlling the sound emission that can be generated with the sound emission device is designed and set up in such a way that the sound wave field generated with the sound emission device can be modulated with the control device in such a way that in an object bridging step following the object raising step, a sound radiation force counteracting the displacement of the object in the direction of the second minimal region is reduced, so that the object can be displaced with the sound radiation force exerted on the object in the object raising step into an environment of the second minimal region, in which the sound radiation force generated by the sound wave field acts on the object in the direction of the second minimal region.It can optionally also be provided that the control device is designed and configured such that in an object lowering step the sound wave field generated by the sound emission device is modulated such that the object is displaced by the action of the external force from an initial minimum region into a target minimum region which is arranged in the sound wave field starting from the initial minimum region in a direction predetermined by the external force.

[0052] In the devices known from practice with which an object can be held in a minimum region of a standing sound wave field by the force of sound radiation, the sound emission devices used are operated continuously and without any modulation of the sound emission. This applies both to those devices with which an object is held in a minimum region which forms immediately in the vicinity of the sound emission device in a near field of sound emissions, and to those devices in which an object is introduced into and held in a minimum region by external manipulation, which forms outside the near field in an area between the sound emission device and a reflecting surface or another appropriately operated sound emission device located opposite.In contrast to these known devices, the control device for the sound emission device is designed and arranged in such a way that the sound waves emitted by the sound emission device can be modulated and thereby the sound radiation force exerted on the object can be specifically changed in order to be able to displace the object within the standing sound wave field selectively between several minimum regions and to retain it in a predetermined minimum region.

[0053] The sound emission device may, if necessary, comprise a plurality of sound generators that can be individually controlled and operated. The control device can be used to control the multiple sound generators differently, thereby influencing and appropriately modulating the sound wave field generated by the sound emission device.

[0054] According to a particularly advantageous embodiment of the inventive concept, it is provided that the control device effects the modulation of the sound wave field by switching the sound emission of the sound emission device on or off. It can also be provided that the control device effects the modulation of the sound wave field by a suitable change in the sound emission of the sound emission device and / or by a suitable change in a distance and / or an alignment between the sound emission device and the surface. The resulting advantages and possibilities have already been described above in connection with the inventive embodiment of the method for displacing the object.

[0055] Furthermore, it can optionally be provided that the control device for controlling the sound emission that can be generated with the sound emission device is designed and set up in such a way that the sound wave field generated with the sound emission device can be modulated with the control device in such a way that in the object deflection step a modulation of the sound wave field is predetermined by a superposition with an object selection frequency predetermined as a function of the object in such a way that the object can be excited to a periodic oscillation around the equilibrium position in a minimum region by the modulated sound wave field.

[0056] According to a further advantageous embodiment of the inventive concept, it can be provided that the sound emission device and the sound wave emitting surface can be displaced relative to one another by means of a translation device, while a standing sound wave field can be generated between the sound emission device and the sound wave emitting surface by means of the sound wave field emission device.The sound emission device can either be arranged so that it can move and be displaced relative to a stationary surface using a translation device, for example a robot arm, or the sound emission device can be mounted and aligned in a fixed position, and the surface onto which the sound emission device radiates and which generates a standing sound wave field by reflecting the sound waves can be displaced using a suitable translation device, for example an XY table. It is also possible for both the sound emission device and the surface to be arranged so that they can move and be displaced relative to one another using a translation device.Optionally, it can be provided that the device has a second sound emission device with at least one second sound generator, which can be operated with the control device, and that a first sound emission device with at least one first sound generator and the second sound emission device can be operated by the control device such that the standing sound wave field is formed between the first sound emission device and the second sound emission device. The two sound emission devices can, for example, be arranged opposite one another on a robot arm and operated such that a standing sound wave field with a plurality of minimal regions of the sound radiation force is formed between the two sound emission devices. An object can be arranged in a floating manner and without any solid body contact in a minimal region.By moving the robot arm, the object suspended between the two sound emission devices can be moved along complex trajectories.

[0057] The device is expediently designed and configured such that the device is suitable and configured for carrying out the method described above.

[0058] In the following, various aspects of the inventive concept are shown and illustrated by means of exemplary embodiments which are shown in the drawings. Fig. 1 shows a schematic representation of a spatial distribution of a sound radiation force potential, the gradient of which at a location within the spatial distribution is a measure of the sound radiation force acting on an object at the location in question which is located in a standing sound wave field between a sound emission device and a surface,

[0059] Fig. 2 is a schematic representation of the sound radiation force acting on the object along a line II in Fig. 1,

[0060] Fig. 3 is a schematic representation of the gravitational force acting on the object along a line II in Fig. 1,

[0061] Fig. 4 is a schematic representation of various process steps during the lifting of the object along the line II in Fig. 1,

[0062] Fig . 5 is a schematic representation of a modulation of the intensity of a sound emission generated by the sound emission device during the execution of a

[0063] Object lifting step,

[0064] Fig. 6 is a schematic representation of a modulation of the intensity of a sound emission generated by the sound emission device during the execution of the method steps of an object deflection step and a subsequently performed object elevation step shown as an example in Fig. 4,

[0065] Fig. 7 is a schematic representation of a modulation of the intensity of a sound emission generated by the sound emission device during an object deflection step and a subsequently performed object elevation step, which differs from the object elevation step shown in Fig. 6,

[0066] Fig. 8 is a schematic representation of a modulation of the intensity of the sound emission generated by the sound emission device, which modulation differs from that shown in Fig. 5 to Fig. 7, during a different execution of process steps during the lifting of the object,

[0067] Fig. 9 is a schematic representation of a process sequence with which an object is lifted from a surface and lifted over several minimal regions within a standing sound wave field,

[0068] Fig. 10 is a schematic representation of a process sequence with which an object is lifted from a surface, lifted into a minimum region of a standing sound wave field, moved laterally over an obstacle and subsequently placed back on the surface, and

[0069] Fig. 11 is a schematic representation of a process sequence by which an object is displaced in a standing sound wave field between two sound emission devices at an acute angle relative to a gravitational force acting on the object,

[0070] Fig. 12 is a schematic representation of the along a line

[0071] II in Fig . 1 acting on the object gravitational force , Fig . 13 a schematic representation of the sound radiation force acting on the object along a line II in Fig . 1 , and

[0072] Fig. 14 is a schematic representation of a temporal change in the position of a first object and a second object different from the first object within a standing sound wave field during the execution of an object deflection step and an object elevation step.

[0073] In Fig. 1, a sound emission device 1 is arranged at a suitable distance from a surface 2. By continuously emitting sound waves with a predetermined wavelength, a standing sound wave field can be generated between the sound emission device 1 and the surface 2. The standing sound wave field exerts a force generated by the sound waves on an object not shown in detail in Fig. 1. Fig. 1 only schematically indicates a spatial distribution of a sound radiation force potential of a sound radiation force field. At each location within the sound radiation force field, a gradient of the sound radiation force potential represents a parameter for a force exerted on the object by the standing sound wave field.For an object with given properties, for example a spherical object with a given dead weight or a given density, a spatial distribution of the sound radiation force potential can be determined and simulated, for example as a Gorkov potential according to a theory developed by L. P. Gor'kov in 1961. With a sufficiently large distance between the sound emission device 1 and the surface 2 and a sufficiently intense sound emission, a number of minimal regions 3 regularly form within the spatial distribution of the standing sound wave field or the associated sound radiation force potential. In an area around a minimal region 3, the sound radiation force exerted on the object by the standing sound wave field always acts in the direction of the minimal region 3. Maximum regions 4 also form, which are shown in Fig.1 are indicated by long dashed lines, in the vicinity of which the sound radiation force exerted on the object by the standing sound wave field is directed away from the maximum region 4. The spatial distribution of minimum regions 3 and maximum regions 4 depends, among other things, on the wavelength of the sound waves emitted by the sound emission device 1 and on the dimensions or shapes as well as on the arrangement and orientation of the sound emission device 1 and the surface 2 relative to one another. In the arrangement shown as an example in Fig. 1, the sound emission device 1 is arranged above the surface 2 in such a way that a gravitational force F also acting on an object. g is also aligned perpendicular to the surface 2 and is directed from the sound emission device 1 in the direction of the surface 2.

[0074] In Fig. 2, to illustrate a sound radiation force Fz , which acts perpendicular to the surface 2 on an object which is located between the

[0075] Acoustic emission device 1 and the surface 2 , a standardized sound radiation force F z / F z0 shown schematically . In an area around a minimal region 3, the normalized sound radiation force F z / F z0 positive, while the normalized sound radiation force F z / F z0 is negative in an area around a maximum region 4. The course of the normalized sound radiation force F z / F z0 along a line II in Fig. 1 corresponds approximately to a sinusoidal curve. For comparison, Fig. 3 shows the curve of a normalized gravitational force F g / F g0 shown , this course being constant along the line II in Fig . 1 .

[0076] It is already known from practice that a sufficiently small and light object, which is placed in the area of ​​a minimal region 3, is moved by a gravitational force F g superimposed and dominant sound radiation force F z can be retained suspended in this area as long as the standing sound wave field is generated by the sound emission device 1. In this case, it is fundamentally necessary, but also sufficient, that the force exerted by the standing sound wave field on the object and counter to the gravitational force F g directed sound radiation force F z in some areas is greater than the gravitational force F g , so that the object can be kept suspended where the sound radiation force F z the gravitational force F g compensated and a deflection of the object towards the surface 2 by an increasing sound radiation force F zis prevented .

[0077] A method sequence according to the invention for a displacement of an object 6 held floating in a first minimal region 5 into a second minimal region 7, which extends in a direction opposite to the gravitational force F g at a greater distance from the surface 2 is shown schematically in Fig. 4. The spherically indicated object 6 is initially floating in an equilibrium position 8 within the first minimal region 5 at a short distance below a sound radiation force-free position 9, in which the sound radiation force F oriented perpendicular to the surface 2 z is zero. The equilibrium position 8 and its small distance to the sound radiation force-free position 9 is determined by the ratio of the sound radiation force F z to the gravitational force F gand corresponds to the distance at which the sound radiation force F, which increases from the position 8 free of sound radiation force towards the surface 2 z the constant gravitational force F acting on object 6 g compensated .

[0078] In an object deflection step 10, the sound wave field generated by the sound emission device 1 is modulated so that the force F g Sound radiation force F acting on object 6 z reduced or completely switched off and the object 6 in the sound wave field is moved from the equilibrium position 8 in the first minimal region 5 by the gravitational force F g in the direction of the gravitational force F acting on object 6 g is shifted into a deflection position 11 .

[0079] In an immediately following object lifting step 12, the sound wave field generated by the sound emission device 2 is modulated such that the object 6 is displaced beyond the first minimal region 5 in the direction of the second minimal region 7, which is opposite to the direction of the gravitational force F g and is arranged at a greater distance from the surface 2 adjacent to the first minimal region 5. Since in the deflection position 11 the sound radiation field exerts a sound radiation force Fz on the object 6 which is greater than the gravitational force Fg exerted on the object 6 and is directed oppositely thereto, the object 6 is accelerated from the deflection position 11 by the greater sound radiation force Fz against the gravitational force Fg and displaced in the direction of the second minimal region 7.

[0080] By means of a suitable temporal progression of the modulation of the standing sound wave field generated by the sound emission device 1, it can be achieved that the object 6 accelerated and displaced in the direction of the second minimal region 7 is displaced into a new equilibrium position 13 in the second minimal region 7 and can then be held suspended there again. For this purpose, the sound wave field is expediently modulated during the displacement of the object 7 out of the first minimal region 5 and into the second minimal region 7 in an object bridging step 14 during the displacement such that by superimposing the sound radiation force F z with the gravitational force F gresulting total force causes a suitable acceleration and subsequent deceleration of the displacement until the object 7 is again held floating, apparently at rest, in the new equilibrium position 13. The positions of the first minimal region 5 and the second minimal region 7 in space and relative to one another do not change during the execution of the object lifting step 12 and the object bridging step 14. In particular, the positions of the first minimal region 5 and the second minimal region 7 in space and relative to one another are identical before and after the displacement of the object 6 from the first minimal region 5 into the second minimal region 7, which is clear from Fig. 4.

[0081] In Fig. 5 to Fig. 8, several different possibilities for a suitable modulation of the standing sound wave field are schematically indicated by way of example. In each case, various time courses of a modulated intensity I of the standing sound wave field generated by the sound emission device 1 are shown by way of example. For simplification, the time course of the intensity I / Io of the sound wave field, normalized to a reference intensity I o, is shown over time, the reference intensity Io corresponding to the intensity of the sound wave field with which the object 6 can be kept floating in an equilibrium position 8, 13.

[0082] In the temporal course of the modulation shown in Fig. 5, the object 6 is initially kept floating in the first equilibrium state 8 in the first minimum region 5 with a normalized intensity I / Io with a value of 1. At time t i, the object elevation step 12 is initiated by significantly increasing the normalized intensity I / Io and changing it to a value of 2 in the embodiment shown. This results in a larger sound radiation force F z applied to the object 6 and the object 6 is accelerated and displaced towards the second minimal region 7 .

[0083] As soon as the object 6 moves beyond a center point of the first minimal region 5, the sound radiation force F zin the direction of the surface 2 and thus counteract the desired displacement of the object 6 in the direction of the second minimal region 7. Therefore, at the relevant time t2 in the object bridging step 14, the acoustic emission device 1 is switched off, so that the normalized intensity I / Io is reduced to zero and only the gravitational force F g acting on the object 6 . The previously applied sound radiation force F z The kinetic energy transferred to the object 6 must be sufficiently large so that the object 6 is lifted in the further course of the object lifting step 12 by the gravitational force F continuously acting on the object 6 g slowed down, but is shifted into the second minimal region 7 into an area in which the object 6 with the help of the sound radiation force F zof the standing sound wave field from the time ta into the second equilibrium position 13 and can be kept floating there again.

[0084] In the time course shown in Fig. 6, which essentially corresponds to the method sequence shown schematically in Fig. 4, the object deflection step 10 is initiated at time ti, the acoustic emission device 1 is switched off and the standardized intensity I / Io is reduced to zero. Then, only the gravitational force F is applied to the object 6. g and the object 6 is accelerated and displaced towards the surface 2.

[0085] At a later time t2, the subsequent object lifting step 12 is initiated by switching on the sound emission device 1 again and generating the standing sound wave field with the standardized intensity I / I o . Due to the already performed displacement of the object 6 in the direction of the surface 2, the object 6 is in a region in which the sound radiation force F z the gravitational force F g predominates and the object 6 is first slowed down until it is in the object deflection position 11 and then against the direction of the gravitational force F g is accelerated again and is displaced towards the second minimal region 7, and thereby has an increasingly greater distance from the surface 2.

[0086] As in the process sequence shown in Fig. 5, in the process sequence shown in Fig. 6, the acoustic emission device 1 is switched off at the time ta in the object bridging step 14, so that the normalized intensity I / Io is reduced to zero and only the gravitational force F gacts on the object 6, while the object 6 leaves the first minimal region 5 and is displaced in the direction of the second minimal region 7. As soon as the object 6 is located in the second minimal region 7 sufficiently close to the second equilibrium position 13 there, the sound emission device 1 is switched on again at time t4 and the object 6 is held in the second equilibrium position 13. Optionally, it can be provided that in the object raising step 12 at a time t4 the sound emission device 1 can be switched on again until time ts in order to additionally accelerate the object 6 in the direction of the second equilibrium position 13 during this time period, so that the object 6 is also accelerated and displaced beyond the second minimal region 7 in order to reach a third equilibrium position located there in a third minimal region and only there is held suspended.Such a process sequence is shown as an example in Fig. 7. For this purpose, after switching on the sound emission device 1 from time t5, a further object bridging step 14 can be carried out and the sound emission device 1 can be switched off until time te. From time te, the sound radiation force F is then z back onto object 6 and causes object 6 to be held in the third equilibrium position in the third minimal region. In this way, object 6 can be moved across several minimal regions in a continuous movement sequence.

[0087] It can also be provided that the sound emission device 1 can be switched on only briefly from a time t4 until the time ts in order to either accelerate the object 6 additionally in the direction of the second equilibrium position 13 or to decelerate it in this short time period, so that the object 6 reaches the second equilibrium position 13 as reliably as possible, but is not displaced too far beyond the second equilibrium position 13 and then swings back and either carries out a damped oscillation around the second equilibrium position 13 or during the swing back again from the area of ​​the second minimal region 7 in the direction of the surface 2 and thus from the catchment area of ​​the sound radiation force F zto move out of the second minimum region 7. A brief activation of the acoustic emission device between times t4 and ts can, if necessary, be repeated several times subsequently and also with different durations in order to effect the fastest and most reliable displacement of the object 6 into the second equilibrium position 13.

[0088] As soon as the object 6 is sufficiently slow and sufficiently close to the second equilibrium position 13, the sound emission device 1 is switched on again at a time te and operated again with the standardized intensity I / Io with a value of 1, so that the object raising step 12 and the object bridging step 14 are completed and the object 7 is again held, apparently at rest and floating, in the second equilibrium position 13 after a short time.

[0089] The process sequences shown as examples in Fig. 6 and fig. 7 make it possible to effect the desired displacement of the object 6 within the standing sound wave field solely by switching the sound emission device 1 on and off at suitable times. A change in the intensity of the sound emission or other properties during operation of the sound emission device 1 is not necessary. The temporal course of the modulation of the intensity I of the sound radiation force F z can be achieved with very simple constructional means, since only the temporally coordinated switching off and on of the sound emission device 1 is required.

[0090] It is also possible that, instead of completely switching the sound emission device 1 off and on again, a different modulation of the standing sound wave field of the sound emission device 1 is specified in order to successively carry out the object deflection step 10 and the object elevation step 12 and, if necessary, the object bridging step 14. The modulation of the standing sound wave field or the intensity I of the sound wave field can be brought about, for example, by changing the amplitude or wavelength of the sound waves generated by the sound emission device 1 or by changing the arrangement or orientation of the sound emission device 1 and the surface 2 relative to one another.

[0091] In the temporal course of the modulation shown exemplary and schematically in Fig . 8 , the object deflection step 10 is initiated at time ti and the sound emission of the sound emission device 1 is changed in such a way that the standardized intensity I / Io is reduced to a value of approximately 0 .5 . Then only a reduced sound radiation force F is applied to the object 6 z which the gravitational force F g is no longer compensated , so that the object 6 is accelerated and displaced in the direction of the surface 2 . To initiate the object lifting step 12 , the sound emission of the sound emission device 1 is changed again at time t2 , so that the standardized intensity I / Io is increased to a value of approximately 1.5 and a significantly larger sound radiation force F zis exerted on the object 6 and the object 6 is thereby accelerated in the direction of the second minimum region 7. At time t3, in the object bridging step 14, the sound emission of the sound emission device 1 is changed again by switching off the sound emission and the sound radiation force F z is reduced to zero, so that the displacement of the object 6 in the direction of the second minimal region 7 is not subjected to a sound radiation force F acting in the opposite direction. z counteracts . As soon as the object has sufficiently approached the second equilibrium position 13 in the second minimal region 7, the intensity I of the sound wave field is gradually increased at time t3 until the object 6 is in the second equilibrium position 13 at time t3 and is held there again apparently floating at rest in the second equilibrium position 13 with the originally predetermined intensity I of the sound wave field.

[0092] In Fig. 9, a method sequence is shown schematically, with which a spherically represented object 7 is first lifted in an object recording step 15 from the surface 2 into the first minimal region 5 by applying a sufficiently large sound radiation force F with the sound emission device 1 zin the direction of the first minimal region 5 which is located at a very short distance above the surface 2. In order to promote the recording and lifting of the object 6, the surface 2 has a suitably shaped depression 16 in which the object 6 is arranged and is located at the beginning of the object recording step 15. As soon as the object 6 has been displaced into the first equilibrium position 10 in the first minimal region 5 by the object recording step 15, the object deflection step 10 and the object lifting step 12 and, if appropriate, the object bridging step 14 can then be carried out in order to displace the object 6 from the first minimal region 5 into the second equilibrium position 13 in the second minimal region 7, which is adjacent to the first minimal region 5 and at a greater distance from the surface 2.

[0093] Subsequently, the object 6 was displaced with an object deflection step 10 and a modified object elevation step 12 as well as a likewise modified object bridging step 14 from the second equilibrium position 13 in the second minimal region 7 via a third minimal region 17 arranged adjacent to the second minimal region 7 directly into the vicinity of a fourth minimal region 18 lying behind this third minimal region 17. This can be achieved without an unnecessary intermediate stop in an equilibrium position in the third minimal region 17 by optionally specifying a somewhat larger deflection from the second equilibrium position 13 in the object deflection step 10 and subsequently applying a particularly large sound radiation force F in the object elevation step 12. zis exerted on the object 6 in order to accelerate the object 6 as strongly as possible in the direction of the fourth minimal region 18. In addition, in a modified object bridging step 14, if necessary several times and in particular in an area around the third minimal region 17, the sound radiation force F z be modified in a suitable manner in order to deal with, for example, an increased sound radiation force F during the displacement of the object 6 z to accelerate the object 6 additionally in the desired direction when the sound radiation force F z in the desired displacement direction, and with a reduced sound radiation force F z to reduce or avoid an undesirable deceleration of the object 6 when the sound radiation force F z acts against the desired direction of displacement.

[0094] In the embodiment shown in Fig. 10, the object 6 is first lifted in an object pickup step 15 from the surface 2 into the first minimal region 5 and then by an object deflection step 10, an object lifting step 12 and an object bridging step 14 into the second minimal region 7 and held there in the second equilibrium position 13 at a greater distance from the surface 2.

[0095] Subsequently, in an object translation step 19, the sound emission device 1 and the surface 2 can be displaced relative to one another. This can be effected either by a displacement of the sound emission device 1 substantially parallel to the stationary surface 2 or by a displacement of the surface 2, for example of an XY table or a displaceable tray, transversely to the sound emission direction of the sound emission device 1. It is also possible for the sound emission device 1 and the surface 2 to be displaced simultaneously, thereby causing a resultant displacement of the sound emission device 1 relative to the surface 2. Preferably, a translational displacement of the sound emission device 1 relative to the surface 2 is effected.The object 6 retained in the equilibrium position 13 in the second minimal region 7 then follows the sound emission device 1 during the relative displacement and consequently performs a displacement relative to the surface 2. Small irregularities in the surface 2, such as depressions or formations, embankments or partitions, can be overcome with the object 6 during the object translation step 19, as long as their effects on the standing sound wave field are small and do not excessively impair the formation of the second minimal region 7, so that the object 6 does not fall out of the second minimal region 7 during the displacement over the obstacle.

[0096] Finally, the object 6 can be deposited again onto the surface 2 in an object depositing step 20 by modulating the sound wave field generated by the sound emission device 1 such that the object 6 is first displaced back into the first minimal region 5 and deposited from the first minimal region 5 onto the surface 2.

[0097] By means of a suitable modulation of the standing sound wave field generated by the sound emission device 1, both the picking up and the setting down of the object 6 can be carried out in such a way that no excessive forces or accelerations are exerted on the object 6, so that, for example, a drop of liquid which is picked up as object 6 from the surface 2, displaced translationally and set down again at a different location on the surface 2, is not excessively deformed or torn apart and is held together as a single drop of liquid due to the higher surface forces during the entire displacement.

[0098] In Fig. 11, an exemplary embodiment is shown in which the standing sound wave field is not generated between a sound emission device 1 and a surface 2 reflecting the sound waves emitted by the sound emission device 1, but between the sound emission device 1 and a second sound emission device 21, which are arranged at a distance from one another and aligned towards one another in such a way that the superposition of the sound waves emitted by the two sound emission devices 1, 21 forms a standing sound wave field with several minimal regions 5, 7, 17 and 18. The alignment of the two sound emission devices 1, 21 can be at an acute or obtuse angle relative to the direction of the gravitational force F gbe specified. In the case of movably arranged sound emission devices 1 , 21 , the orientation of the two sound emission devices 1 , 21 relative to the direction of the gravitational force F g be changed while an object 6 is kept floating in the area of ​​a minimal region 5, 7, 17, 18. The orientation of the two sound emission devices 1, 21 can also be changed during the execution of an object deflection step 10, an object lifting step 12 or an object bridging step 14 and optionally also during an object translation step 19 or an object setting down step 20. The modulation of the standing sound wave field or the sound radiation force F z can choose between the two

[0099] Acoustic emission devices 1 , 21 can be achieved not only by the measures already described but also by changing the phase relationship between the acoustic emissions of the two acoustic emission devices 1 , 21 .

[0100] In Fig. 14, a temporal course of the positions or their changes of two different objects 6, 22 is shown as an example and schematically. These objects are located in two adjacent minimal regions within a standing sound wave field that is formed between a sound-emitting device and a sound-reflecting surface. For clarification, the gravitational force F g and the sound radiation force F z each shown in a standardized manner, which act on the two objects 6, 22 at the beginning of the time course.

[0101] The other object 22 has a higher dead weight or mass than object 6, so that a greater gravitational force Fg acts on the other object 22. The standing sound wave field generated by the acoustic emission device is sufficiently intense that both object 6 and the heavier object 22 are each held in an equilibrium position in two adjacent minimal regions.

[0102] From time t1, an object deflection step 10 is carried out, wherein a modulation of the standing sound wave field is carried out by superimposing the sound waves emitted by the sound emission device with an object selection frequency predetermined as a function of the object 6, such that the modulated sound wave field excites the object 6 to a periodic oscillation around its equilibrium position in its minimum region. The object selection frequency depends significantly on the dead weight of the object 6. With increasing duration of the object deflection step 10, an amplitude of the periodic deflection of the object 6 around its equilibrium position increases.In contrast, the heavier object 22 is not excited to a periodic oscillation by the modulation with the object selection frequency appropriate for the object 6, but remains essentially in its equilibrium position with small deflections.

[0103] From time t2, the object elevation step 12 is then carried out. In this case, the object 6 is raised by the object elevation step 12 due to the changed sound radiation force F z sufficiently accelerated and shifted into the neighboring minimal region. A comparably large sound radiation force F z also acts on the heavier object 22, but cannot accelerate this heavier object 22 sufficiently, so that the heavier object 22 is briefly deflected more strongly than before, but does not leave its minimal region.

[0104] In this way, by means of a suitably predetermined object selection frequency and a suitably carried out object deflection step 10, it can be achieved that two objects 6, 22 initially held floating in different minimal regions are transferred into a single minimal region and are then held together in this minimal region.

Claims

PATENT CLAIMS 1. A method for lifting a non-gaseous object (6) in a gaseous environment against an external force acting on the object (6), wherein a standing sound wave field is generated by a sound emission device (1) with at least one sound generator between the sound emission device (1) and a sound wave radiating surface (2), which forms a plurality of minimal regions (3, 5, 7, 17, 18) between the sound emission device (1) and the surface (2), in which minimal regions the sound wave field has a sound radiation force (F z ) is generated, which acts on the object (6) in the vicinity of a minimal region (3, 5, 7, 17, 18) in the direction of the respective minimal region (3, 5, 7, 17, 18), so that the object (6) is retained in an equilibrium position (8) in the minimal region (3, 5, 7, 17, 18) when the sound radiation force (F z) is equal to the external force, characterized in that in an object lifting step (12) the sound wave field generated by the sound emission device (1) is modulated such that the object (6) is displaced beyond a first minimum region (5) in the direction of a second minimum region (7) which is arranged adjacent to the first minimum region (5) opposite to the direction of the external force.

2. Method according to claim 1, characterized in that the sound wave field before the object raising step (12) has a first minimum region (5) and a second minimum region (7) that the object (6) in the object lifting step (12) from the first minimum region (5) towards the second minimal region (7), and that the object (6) is moved after the object lifting step (12) by the sound radiation force (F z ) of the sound wave field is retained in the second minimal region (7) of the sound wave field.

3. Method according to claim 1 or claim 2, characterized in that the sound wave field after the object enhancing step (12) forms the same minimal regions (3, 5, 7, 17, 18) as before the object enhancing step (12).

4. Method according to one of the preceding claims, characterized in that the minimal regions (3, 5, 7, 17, 18) of the sound wave field are formed outside a closed resonance chamber.

5. Method according to one of the preceding claims, characterized in that in an object deflection step (10) preceding the object lifting step, the sound wave field generated by the sound emission device (1) is modulated such that the sound radiation force (F z) is reduced and the object (6) in the sound wave field is displaced from the equilibrium position (8) in the first minimum region (5) in the direction of the external force acting on the object.

6. Method according to one of the preceding claims, characterized in that in an object bridging step (14) the sound generated by the sound emission device (1) Sound wave field is modulated in such a way that during a displacement of the object (6) a sound radiation force (F z ) is reduced.

7. The method according to claim 6, characterized in that in an object bridging step (14) the sound wave field generated by the sound emission device (1) is modulated, if necessary several times, such that a sound radiation force (F z) is reduced, so that the object (6) is subjected to the sound radiation force (F z ) into an environment of a third (17) minimal region arranged behind the first minimal region (5) in the direction of the second minimal region (7), in which the acoustic radiation force (F z ) acts on the object (6) in the direction of the third minimal region (17).

8. Method according to one of the preceding claims, characterized in that in an object lowering step (20) the sound wave field generated by the sound emission device (1) is modulated such that the object (6) is displaced by the action of the external force from an initial minimum region (3, 18, 17, 7) into a target minimum region (3, 17, 7, 5) which, starting from the initial minimum region (3, 18, 17, 7), is arranged in the sound wave field in a direction predetermined by the external force.

9. Method according to one of the preceding claims, characterized in that in an object setting-down step (20) the sound wave field generated by the sound emission device (1) is modulated such that the object (6) is displaced from a minimal region (3, 5, 7, 17, 18) onto the surface (2).

10. Method according to one of the preceding claims, characterized in that in the object deflection step (10) and / or in the object lifting step (12) the Modulation of the sound wave field is effected by switching on or off the sound emission of the sound emission device (1).

11. Method according to one of the preceding claims 1 to 9, characterized in that in the object deflection step (10) and / or in the object lifting step (12) the modulation of the sound wave field is effected by a suitable change in the sound emission of the sound emission device (1) and / or by a suitable change in a distance and / or an alignment between the sound emission device (1) and the surface (2).

12. Method according to one of the preceding claims, characterized in that in the object deflection step (10) a modulation of the sound wave field is carried out by a superposition with an object selection frequency predetermined as a function of the object (6) in such a way that the object (6) is excited by the modulated sound wave field to a periodic oscillation around the equilibrium position (8) in a minimum region (3, 5, 7, 17, 18).

13. Method according to one of the preceding claims, characterized in that in an object translation step (19) the sound emission device (1) and the sound wave emitting surface (2) are displaced relative to one another, while a standing sound wave field is generated between the sound emission device (1) and the sound wave emitting surface (2), so that an object (6) located in a minimal region (3, 5, 7, 17, 18) is displaced relative to the surface (2) in a direction parallel to the surface (2).

14. Method according to one of the preceding claims, characterized in that the sound wave-emitting surface (2) is formed by a second sound emission device (21) with at least one second sound generator, and in that a first sound emission device (1) with at least one first sound generator is operated such that the standing sound wave field is formed between the first sound emission device (1) and the second sound emission device (21).

15. Device for lifting a non-gaseous object (6) in a gaseous environment against an external force acting on the object (6), the device comprising a control device and a sound emission device (1) with at least one sound generator, wherein the sound emission device (1) can be operated with the control device in such a way that a standing sound wave field can be generated between the sound emission device (1) and a sound wave-emitting surface (2), which standing sound wave field can be generated between the Sound emission device (1) and the surface (2) forms several minimal regions (3, 5, 7, 17, 18) in which the sound wave field has a sound radiation force (F z ) is generated, which acts on the object (6) in the vicinity of a minimal region (3, 5, 7, 17, 18) in the direction of the respective minimal region (3, 5, 7, 17, 18), so that the object (6) is retained in an equilibrium position (8) in this minimal region (3, 5, 7, 17, 18) when the sound radiation force (F z) is equal to the external force, characterized in that the control device for controlling the sound emission that can be generated with the sound emission device (1) is designed and set up in such a way that in an object lifting step (12) the sound wave field generated with the sound emission device (1) can be modulated in such a way that the object (6) is displaced beyond the first minimum region (35, 7, 17) in the direction of a second minimum region (7, 17, 18) which is arranged adjacent to the first minimum region (5, 7, 17) opposite to the direction of the external force.

16. Device according to claim 15, characterized in that the control device for controlling the sound emission that can be generated with the sound emission device (1) is designed and set up in such a way that in an object deflection step (10) preceding the object lifting step (12), the sound wave field generated with the sound emission device (1) can be modulated in such a way that the sound radiation force (F z ) is reduced and the object (6) in the sound wave field from the equilibrium position (8) in the first minimal region (5, 7, 17) is displaced in the direction of the external force acting on the object (6).

17. Device according to claim 15 or claim 16, characterized in that the control device for controlling the sound emission that can be generated by the sound emission device (1) is designed and set up in such a way that the control device can modulate the sound wave field generated by the sound emission device (1) in such a way that in an object bridging step (14) following the object raising step (12), a sound radiation force (F z ) is reduced, so that the object (6) is subjected to the sound radiation force (F z ) can be shifted into an environment of the second minimal region (7, 17, 18), in which the sound radiation force (F z ) acts on the object in the direction of the second minimal region (7, 17, 18).

18. Device according to one of claims 15 to 17, characterized in that the control device effects the modulation of the sound wave field by switching on or off the sound emission of the sound emission device (1).

19. Method according to one of claims 15 to 17, characterized in that the control device is used to modulate the sound wave field by a suitable change in the sound emission of the sound emission device (1) and / or can be effected by a suitable change in a distance and / or an alignment between the sound emission device (1) and the surface (2).

20. Device according to one of claims 15 to 19, characterized in that the control device for controlling the sound emission that can be generated with the sound emission device (1) is designed and set up in such a way that the control device can modulate the sound wave field generated with the sound emission device (1) in such a way that in the object deflection step (10) a modulation of the sound wave field is predetermined by a superposition with an object selection frequency predetermined as a function of the object (6) in such a way that the object (6) can be excited to a periodic oscillation around the equilibrium position (8) in a minimum region (3, 5, 7, 17, 18) by the modulated sound wave field.

21. Device according to one of the preceding claims 15 to 20, characterized in that the sound emission device (1) and the sound wave radiating surface (2) can be displaced relative to one another by means of a translation device, while a standing sound wave field can be generated between the sound emission device (1) and the sound wave radiating surface (2) by means of the sound wave field emission device (1).

22. Device according to one of the preceding claims 15 to 21, characterized in that the device has a second sound emission device (21) with at least one second sound generator, which is connected to the control device is operable, and that a first sound emission device (1) with at least one first sound generator and the second sound emission device (21) can be operated by the control device such that the standing sound wave field is formed between the first sound emission device (1) and the second sound emission device (21).

23. Device according to one of the preceding claims 15 to 22, characterized in that the device is suitable and arranged to carry out the method according to one of claims 1 to 14.

Images