Method and system for stabilizing an external load

Abstract

Method for controlling the attitude of an external load (13) which is movably attached to the flying object (11) outside of a flying object (11) by means of a load-carrying device (12), wherein a stabilizing device (20) is provided which comprises at least one inertia wheel (21) arranged on the external load (13), wherein, for controlling the attitude of the external load (13), the at least one inertia wheel (21) is set in a rotary movement by means of a drive which is operatively connected to the inertia wheel (21), characterized in that a movement of the external load (13) during flight of the flying object (11) is detected by means of a movement detection device of the stabilizing device (20), wherein a control signal for controlling the drive is generated by means of the stabilizing device (20) as a function of the detected movement,that the rotational movement of the at least one inertia wheel (21) resulting from the control signal at least partially counteracts the movement of the external load (13), wherein image data of the external load are recorded with the aid of a camera arranged downwards on the flying object, wherein movements of the external load are then detected from the image data with the aid of an image recognition device.

Description

The invention relates to a method for controlling the position of an external load which is movably fastened to the flying object outside an aerial object by means of a load bearing device.The invention also relates to a system comprising a flying object for this purpose.Rotorcraft, in particular helicopters, are distinguished inter alia by the ability to transport loads to locations which are difficult to access or pick up loads which can only be conveyed and reached with conventional means. A particular type of transport is represented by external load transport, in which the load is fastened by means of a carrying cable or carrying cable harness, optionally in the form of a net, to one or more load hooks on the helicopter or on an external winch. However, adding an external load to a helicopter alters the system dynamics and reduces flight performance. In addition, the pilot's flight control task is extended by the control task of the external load, since the complexity of the overall system to be flying is increased by the external load. This ultimately leads to an increase in the burden on the pilot and generally to a reduction in flight safety.In the case of outdoor load transport, there is firstly the risk of uncontrollable, low-frequency pendulum movements as a result of aerodynamic disturbances or control inputs. The swinging may transition to motion of unstable oscillations, which may also be multiplied by pilot inputs. This can ultimately lead to pilot induced oscillations. Because the pilots do recognize the dynamic influence of an oscillating external load from the helicopter, but do not usually see the external load, there is the risk that in certain cases the correction control inputs executed by the pilot for damping the entire system will further increase the pendulum movement of the external load. This is because the pilot intuitively tries to counter the transverse force exerted on the helicopter by the oscillating external load, rather than flying behind the load to a limited extent to release the external load from transverse forces. Strong pendulum movements of the external load pose a risk to the overall system and its crew, since its influence on the helicopter can lead to it no longer being controllable.For example, DE 10 2008 025 298 A1 discloses a method and a device for damping vertical oscillations in a helicopter with an attached external load, wherein the excitation of at least two eigenmodes of the vertical oscillations is detected with oscillation sensors on the helicopter and, in contrast to the vertical oscillations, are initiated as a function of phases and amplitudes of the detected excitations between the load-receiving point and the load harness with an actively controlled linear actuator.Load stabilization systems are also disclosed in DE 22 44 938 C3, U.S. Pat. No. 3,833,189 A and U.S. Pat. No. 3,756,543 A, in which the pendulum movement of the external load is measured. The rate of change of the angle between the support cable and the helicopter vertical and the filtered rates thereof are fed into the controller as a controlled variable, resulting in a stabilization system which responds to the helicopter flight control.For passive assistance of the pilot during an external load transport, a method and a device for displaying the position and the movement state of a load attached to a helicopter are disclosed, for example, from DE 10 2005 022 231 A1 and DE 10 2005 022 212 A1. In this case, the current position of the external load is measured by means of a sensor attached to the external load, wherein a control instruction is visually displayed to the pilot in the case of load oscillations. If the pilot follows this indicated control instruction, this leads to stabilization of the external load.DE 10 2010 023 228 A1 discloses a stabilizing device for helicopters, which has a movement space determination unit which is configured to determine a free movement space in which the helicopter can move without collisions with external load. In this case, control signals are generated as a function of the detected pendulum movement of the external load and as a function of the determined movement space and are impressed on the flight control.US 2011 / 0137497 A1 discloses a pendulum detection device in which the angle of the pendulum movement of an external load arranged on a helicopter is calculated in two directions. With the aid of a display unit, the determined pendulum angles are then displayed in the pendulum plane in relation to the helicopter.Systems which detect the oscillation of the external load and actively intervene in the flight control in order to damp the oscillation of the external load have the disadvantage that these systems actively intervene in the flight situation and possibly override the pilot. Moreover, such systems only function if the helicopter can move in space without collisions. However, if, for example, the placing of an external load on a moving ground is provided, for example on a ship, these forms of vibration damping can bring about critical flight situations.Systems which only indicate the offset of the external load with respect to the flying object are informative to the pilot, but leave the intervention in the flight situation exclusively to the pilot. In the case of precise positioning tasks within an obstacle gate which is difficult to see, there is also the risk that, during compensating movements carried out by the pilot, the external load or the helicopter may collide with such an obstacle, which may lead to a crash. The higher the pilot load, the more likely is a possible incorrect input of control commands by the pilot, so that the risk potential increases accordingly here.Another problem arises when the external load is placed on an uneven or inclined surface. It is advantageous if the load is deposited uniformly or flat relative to the underlying surface, so that it is deposited on the underlying surface in a non-tilting manner.EP 4 180 021 A1 discloses a patient carrier which is to be arranged on a helicopter. The patient support has a plurality of gyroscopes which serve to control the position of the patient support by means of a flywheel.It is therefore the object of the present invention to specify an improved method for flight operation with which an external load can be safely transmitted inaccurately within system limits.The object is achieved according to the invention by the method for position control of an external load according to claim 1. Advantageous embodiments of the invention are then found in the corresponding dependent claims.According to claim 1, a method for controlling the position of an external load is proposed, wherein the external load is movably fastened or arranged on the flying object outside an flying object by means of a load carrier device. Such a load bearing device can be, for example, a bearing cable or a bearing rod which is fastened to the flying object with a first end, while the external load is fastened to an opposite second end of the load bearing device and is thus arranged movably on the flying object. At the second end, a load-receiving device can be provided in order to connect the external load to the load-carrying device at the second end.In this case, the load carrying device and / or the external load is arranged movably on the load receiving device, such that the external load is movable with respect to the flying object. Movable means here in particular that the external load is arranged or fastened rotatably with respect to the flying object. The external load is arranged on the flying object with the aid of the load-bearing device in particular in such a way that the external load is rotatable in at least one rotation plane or rotation plane, preferably in all three rotation planes.According to the invention, it is now provided that a stabilization device is provided which comprises at least one inertia wheel arranged on the external load, wherein, for the position control of the external load, the at least one inertia wheel is set into a rotational movement by means of a drive operatively connected to the inertia wheel.Such inertia wheels, also called flywheels, are a type of high-mass gyros that stabilize the orientation of the external load or that influence or control the position of the external load. After the at least one inertia wheel has been set into a rotational movement by means of the drive, the inertia wheel is then held at a stabilizing or position-influencing, usually very high rotational speed for a certain period of time, wherein the rotational speed can also vary. The inertia wheel generates a rotational impulse and thereby a stabilizing or position-influencing spin.This stabilizing angular momentum allows damping of rotational movements of the external load, in order to be able to better control and stabilize the external load even in difficult situations.The invention makes it possible to dispense with active interventions in the flight control in order to stabilize external loads or to control them with respect to position, wherein position control is also possible if the external load is intended to be deposited in a difficult obstacle gate by precise positioning tasks.It is advantageous if the rotational movement of the at least one inertia wheel takes place before the external load is set down.It is also conceivable that the rotational movement of the at least one inertia wheel takes place before the discharge of the external load from the flying object. That is to say that before the external load is discharged from the flying object in the direction of the ground by means of the load bearing device, as a result of which the distance of the external load from the flying object is constantly increased and therefore the radius of movement constantly increases, the rotational movement of the at least one inertia wheel is generated, with the result that the negative effects of the swirl generation by the pilot can already be compensated for on the flying object itself.However, it is also conceivable for the rotational movement of the at least one inertia wheel to be generated after the external load has been deposited, for example on a moving underlying surface such as a ship. As a result, (rotational) moments acting from the outside can be stabilized, which are caused, for example, by the movement of the ship or by other forces acting on the external load.The position control of the external load is understood in particular to mean the stabilization of the external load. In this case, the external load is stabilized in such a way that a change in position is made more difficult on account of the rotational pulses and the force required for a change in position becomes greater. However, a position control of the external load is also understood to mean that the alignment or position of the external load is changed or influenced in a targeted manner by the angular momentum of the helical gears. This is used, for example, in order to place the external load on an inclined surface in a substantially non-tilting manner.A flying object in the sense of the present invention is understood to mean, in particular, an aircraft, a rotorcraft such as, for example, a helicopter. The term flying object comprises in this case both flying objects inside and outside the earth's atmosphere.According to one embodiment, it is provided that the stabilizing device is provided in such a way that it comprises at least two inertia wheels arranged on the external load in such a way that their axes of rotation are aligned orthogonally to one another, wherein, for the purpose of controlling the position of the external load, the at least two inertia wheels are set into a rotational movement by means of the drive operatively connected to the inertia wheels.According to one embodiment, it is provided that the stabilizing device is provided in such a way that it comprises at least three inertia wheels arranged on the external load in such a way that their axes of rotation are aligned orthogonally to one another, wherein, for the purpose of controlling the position of the external load, the at least three inertia wheels are set into a rotational movement by means of the drive operatively connected to the inertia wheels.By arranging 2 or 3 inertia wheels, which are each aligned orthogonally to one another, position control of the external load can take place in a plurality of spatial directions. If 3 inertia wheels are provided, which are oriented orthogonally to one another, the external load can be stabilized or controlled in particular with respect to a rotational movement in all three rotational axes.According to one embodiment, it is provided that at least two inertia wheels are simultaneously set into a rotational movement. According to one embodiment, it is provided that at least 3 inertia wheels are simultaneously set into a rotational movement.According to one embodiment, it is provided that the rotational speed of the at least one inertia wheel varies.By varying the rotational speed of at least one inertia wheel, it is possible to react to a changing movement of the external load, in order to achieve the best possible damping or stabilization or control. This not only permits damping of the external load movement, but also an active control of the position of the external load.According to the invention, it is provided that a movement of the external load in the flight of the flying object is detected by means of a movement detection device of the stabilization device, wherein a control signal for controlling the drive is generated by means of the stabilization device as a function of the detected movement in such a way that the rotational movement of the at least one inertia wheel resulting from the control signal at least partially counteracts the movement of the external load.Such a movement detection device is a camera which is arranged on the flying object and is oriented in the direction of the ground in order to record the external load. The image data recorded in this case contain the external load, wherein movements of the external load are then detected with the aid of an image recognition device. From these movements of the external load detected in this way, such as, for example, rotational rate, acceleration values and translatory movements or pendulum movements, control signals can then be generated for controlling the drive of the at least one inertia wheel and used for controlling the drive in order to generate a rotational movement of the at least one inertia wheel which at least partially counteracts the detected movement of the external load.According to one embodiment, it is provided that the external load is aligned in a targeted manner on the underlying surface on which the external load is to be deposited, in that the stabilization device is used to generate a control signal for controlling the drive as a function of the position or orientation of the underlying surface in relation to the external load in such a way that the rotational movement of the at least one inertia wheel resulting from the control signal approximates the external load with respect to the underlying surface in terms of the alignment.The object is also achieved according to the invention with the system according to claim 6, comprising a flying object and an external load arranged movably on the flying object via a load bearing device, wherein the system comprises a stabilization device configured to carry out the method described above.The invention is explained in more detail by way of example with reference to the attached figure. It shows: FIG. 1 shows a schematic illustration of the system with a stabilization device.FIG. 1 shows a schematically greatly simplified illustration of a system 10 which has a helicopter as flying object 11 and an external load 13 which is arranged movably on helicopter 11 via a load bearing device 12. The load bearing device 12 is fastened with a first end to the helicopter 11, while the outer load 13 is fastened to the second end of the load bearing device 12. The load bearing device 12 can be a load cable, for example.The external load 13 is arranged on the helicopter 11 via the load bearing device 12 in such a way that it can execute a relative movement with respect to the helicopter 11. In particular, pendulum movements 14 and rotational movements 15 are conceivable here.On the outer load, a stabilizer 20 is arranged, which comprises three inertia wheels 21 a, 21 b, 21 c. The inertia wheels 21 are each aligned orthogonally to one another and connected to a drive 22 so that the inertia wheels 21 can be set in a rotational movement. Each inertia wheel 21 a, 21 b, 21 cmay be individually and independently rotated by the drive unit 22 by the other. In particular, the rotational rate of each inertia rate may vary as compared to the others.The stabilization device furthermore has an electronic computing unit 23, which is designed to actuate the drive unit 22. The electronic computing unit 23 generates control signals in order to actuate the drive unit 22 such that one, two or all three inertia wheels are set into a rotational movement.The electronic computing unit 23 furthermore has a sensor 24, which is designed to detect a movement of the external load 13. The sensor 24 supplies sensor signals which correspond to the movement of the external load 13 in the respective direction or the respective direction of rotation.The electronic computing unit 23 is configured such that corresponding control signals for the drive unit 22 are generated on the basis of the detected movement of the external load 13, in order to set the inertial wheels 21 in a rotational movement and thereby stabilize the external load 13. The detected movement is thereby damped and at the same time the external load 13 is stabilized, so that movements by the flying object 11 are not transferred in an uncontrolled manner to the external load 13 and generate corresponding disruptive movements there.List of reference characters10 System 11 Flying object 12 Load carrying device 13 External load 14 Pendulum movement 15 Rotational movement 20 Stabilizing device 21 Inertia wheel 22 Drive unit 23 Electronic computing unit 24 Sensor

Claims

Method for controlling the position of an external load (13) which is movably fastened to the flying object (11) outside an flying object (11) by means of a load carrying device (12), wherein a stabilization device (20) is provided which comprises at least one inertia wheel (21) arranged on the external load (13), wherein, for controlling the position of the external load (13), the at least one inertia wheel (21) is set into a rotational movement by means of a drive which is operatively connected to the inertia wheel (21), characterized in that a movement of the external load (13) in the flight of the flying object (11) is detected by means of a movement detection device of the stabilization device (20), wherein a control signal for controlling the drive is generated by means of the stabilization device (20) as a function of the detected movement in such a way, the rotational movement of the at least one inertial wheel (21) resulting from the control signal at least partially counteracts the movement of the external load (13), wherein image data of the external load are recorded with the aid of a camera arranged downwards on the flying object, wherein movements of the external load are then detected from the image data with the aid of an image recognition device.Method according to claim 1, characterised in that the stabilising device (20) is provided in such a way that it comprises at least two inertia wheels (21) arranged on the external load (13) in such a way that their axes of rotation are aligned orthogonally to one another, wherein, for the position control of the external load (13), the at least two inertia wheels (21) are set into a rotational movement by means of the drive operatively connected to the inertia wheels (21).Method according to claim 1, characterised in that the stabilising device (20) is provided in such a way that it comprises at least three inertia wheels (21) arranged on the external load (13) in such a way that their axes of rotation are aligned orthogonally to one another, wherein, for the position control of the external load (13), the at least three inertia wheels (21) are set into a rotational movement by means of the drive operatively connected to the inertia wheels (21).Method according to claim 2 or 3, characterised in that at least two inertia wheels (21) are set into a rotational movement simultaneously.Method according to any one of the preceding claims, characterized in that the speed of rotation of the at least one inertia wheel (21) varies.System (10) comprising a flying object (11) and an external load (13) movably arranged on the flying object (11) via a load bearing device (12), characterized in that the system (10) comprises a stabilization device (20) configured to carry out the method according to one of the preceding claims.

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