Crane and method for controlling the crane

Abstract

A crane, in particular a revolving tower crane or a jib crane, comprising: a sling (7) extending from a jib (2) and carrying a lifting hook (8), wherein a suspension device (12) is mounted on the lifting hook (8) to which a load (11) is fastened, the load being suspended by the suspension device (12) in a manner spaced apart from the lifting hook (8); a determination device (60) for determining the position and / or deflection of the load (11); and an electronic control device (3) for controlling a drive device for moving crane elements and transferring the lifting hook (8) as a function of the detected position and / or deflection of the load (11), wherein the determination device (60) has: a first determination device; Determination means (63; 65) for determining the position and / or deflection of a lifting hook (8); an inertial measurement device (66, 67) mounted on a suspension device (12) and / or on a load (11) and having an acceleration and rotation rate sensor device for providing an acceleration signal and a rotation rate signal; and a second determination device for determining and / or estimating the deflection and / or position of the load (11) based on the acceleration signal and the rotation rate signal of the inertial measurement device (66, 67) mounted on the suspension device (12) and / or on the load (11) and based on the signal of the first determination device (63, 65) characterizing the position and / or deflection of the lifting hook (8).

Description

Technical Field

[0001] The invention relates to a crane, in particular a revolving tower crane, comprising a sling extending from a boom and carrying a lifting hook to which a suspension device carrying a load is connected, a determination device for determining a load position and / or a swaying movement, a drive device for moving crane elements and repositioning the lifting hook, and a control device for controlling the drive device as a function of the determined load position and / or swaying movement, and also to a method for controlling such a crane, wherein the drive of the drive device is influenced as a function of the determined load position and / or swaying movement. Background Art

[0002] In order to be able to reposition the lifting hook of a crane along a travel path or between two destination points, various drive devices usually have to be operated and controlled.

[0003] Here, for example, the operator of a rotating tower crane, jib crane or bridge crane (or loading bridge) usually controls the drive directly, so that a lot of practice and concentration are required to move the load quickly to the unloading point and to lower it safely. In particular, driving the crane quickly leads to large swings of the load, which can only be damped very slowly due to the low damping. Avoiding this manually is very difficult and even experienced crane operators are unlikely to succeed or will hardly succeed.

[0004] The complexity of the oscillating movement is further increased if the load is not suspended directly on the lifting hook, but is suspended at a distance from the lifting hook by means of a suspension device (Anschlagmittel) in the form of, for example, a cable, an intermediate hanger, one or more chains, an extension net or simply another cable. The influence or proportion of the load relative to the oscillating movement of the lifting hook will also be different the longer the suspension device is in relation to the depth of descent and depending on the ratio of the mass of the load to the mass of the lifting hook or the hook block. Double oscillating movements can occur, in which the oscillating movement of the lifting hook is superimposed on the oscillating movement of the load or the suspension device which is spaced apart from the hook. This superposition of oscillating movements makes it more difficult for the crane operator to operate the drive device so that the double oscillating movement is suppressed or does not occur at all.

[0005] For some crane types, the crane structure itself is telescopic and can swing on its own, which is almost impossible for the crane operator to predict due to the various axes of movement. For example, in the case of a revolving tower crane, in which the cables run from a trolley that can be moved on the boom of the crane, it is usually necessary to operate and control a revolving mechanism, by which the tower with the boom or jib arranged thereon is rotated relative to the tower about an upright axis of rotation, a trolley drive, by which the trolley can be moved along the boom, and a lifting mechanism, by which the cables can be adjusted and thus the lifting hook can be raised and lowered. For cranes with a telescopic boom that can be pitched, in addition to the revolving mechanism, by which the boom or the superstructure carrying the boom is rotated about an upright axis, and the lifting mechanism for adjusting the cables, a luffing drive for pitching the boom upwards and downwards and a telescopic drive for extending and retracting the telescopic section are operated, and in the case of a boom on the telescopic boom, a boom drive may also be operated. In the case of hybrids of this crane and similar crane types, for example a revolving tower crane with a luffing jib or a derrick crane with a luffing counter-jib, it may also be necessary to control further drive devices separately.

[0006] In this case, the crane operator usually drives and controls the drive device by means of corresponding operating elements, for example in the form of joysticks, toggle switches, knobs and sliders, which according to experience requires a great deal of feel and experience in order to approach the target points quickly and gently without the hook making larger swinging movements. Although the travel between the target points should be as fast as possible to achieve high working efficiency, the stop at the respective target point should be gentle without the hook and the load connected thereto swinging back.

[0007] Such control of the crane drive is very tiring for the crane operator due to the concentration required, especially due to the often repetitive travel paths and monotonous tasks. In addition, if the crane operator is not able to operate the crane's operating levers or operating elements with sufficient agility, due to reduced concentration or insufficient experience with the respective crane type, greater oscillations or double oscillations of the lifted load may occur, with corresponding potential dangers. In practice, even for experienced crane operators, the crane drive can sometimes quickly cause greater oscillations of the load, which can only be dissipated very slowly.

[0008] In order to deal with the problem of unwanted swinging movements, it has been proposed to provide a swing damping device for the crane control device, which intervenes in the control through a control module and influences the control of the drive device, for example, by operating an operating lever too quickly or too strongly to prevent or weaken a large acceleration of the drive device, or to limit a certain travel speed under greater loads, or to actively intervene in the travel movement in a similar way to prevent excessive swinging of the lifting hook.

[0009] Such sway damping devices for cranes are known in various embodiments, for example by controlling the swivel drive, the pitch and the trolley drive as a function of specific sensor signals (e.g. tilt and / or gyroscopic signals). For example, documents DE 20 2008 018 260 U1 or DE 10 2009 032 270 A1 show known load sway dampers on cranes, to which the subject matter is explicitly cited with regard to the basic aspects of the sway damping device. For example, in DE 20 2008 018206 U1, the angle of the cable relative to the vertical and its change in the form of the angular velocity of the cable are measured by a gyroscopic unit in order to automatically intervene in the controller when the angular velocity of the cable relative to the vertical exceeds a limit value.

[0010] Furthermore, documents EP 16 28 902 B1, DE 103 24 692 A1, EP 25 62 125 B1, US 2013 01 61279 A, ​​DE 100 64 182 A1 or US 55 26 946 B each show concepts for a closed-loop control of a crane which take into account the pendulum dynamics or oscillation and the drive dynamics. Such closed-loop control on cranes taking into account the swing dynamics has been the subject of various scientific publications, see, for example, E. Arnold, O. Sawodny, J. Neupert and K. Schneider, "Anti-sway system for boom cranes based on a model predictive control approach", IEEE International Conference on Mechatronics and Automation, 2005, Niagara Falls, Ont., Canada, 2005, pp. 1533-1538 Vol. 3. and Arnold E., Neupert J., Sawodny O., "Anti-sway system for boom cranes based on a model predictive control approach", IEEE International Conference on Mechatronics and Automation, 2005, Niagara Falls, Ont., Canada, 2005, pp. 1533-1538 Vol. 3. =Trajektoriengenerierung für flachheitsbasierte Folgeregelungen am Beispieleines Hafenmobilkrans (Generation of model-predicted trajectories for flatness-based subsequent control using the example of a mobile harbour crane)”, Automatisierungstechnik, 56 (8 / 2008), or J. Neupert, E. Arnold, K. Schneider and O. Sawodny, “Tracking and anti-sway control for boom cranes”, Control Engineering Practice, 18, pp. 31-44, 2010, doi:10.1016 / j.conengprac.2009.08.003.

[0011] Furthermore, attempts have been made to model the double pendulum motion which occurs in the described manner when the load is suspended at a distance from the lifting hook via a suspension device, see Schaper, Ulf et al., "A load position observer for cranes with gyroscope measurements", Proceedings of the 18th World Congress, International Federation of Automatic Control, Milan (Italy), August 28-September 2, 2011, pp. 3563-3568. In this case, the deflection angle and the deflection acceleration of the suspension cable are measured by means of a gyroscope in order to determine the position of the load suspended from the suspension device according to the kinematic model of the double pendulum. However, this requires the knowledge of the additional length of the suspension device or the distance between the load and the lifting hook and the moments of inertia of the load and the suspension device. If the length of the suspension device or the distance between the load and the hook or the moments of inertia of the load and the suspension device relative to the crane hook are not additionally known, this method cannot reliably determine the position of the load or its deflection.

[0012] The basic goal is therefore to detect or determine the load position or its double pendulum movements as accurately as possible in order to be able to actively counteract them by regulation. On the one hand, such regulation can be used as an auxiliary system, which allows the crane operator to specify the load movement directly via the operating device (instead of the bridge or trolley movement). This support can increase work safety and productivity. In addition, damping is an important prerequisite for the complete automation of crane movements.

[0013] In this context, there is a particular problem that systems for active damping have hitherto not been retrofittable in a cost-effective manner or not generally available. A further disadvantage is that the dampers known hitherto are very expensive and generally do not adequately take into account possible double pendulum movements which, in the case of elongated suspensions with relevant spacings between load and lifting hook, result from the superposition of the oscillating movement of the lifting hook itself and the oscillating movement of the load relative to the lifting hook. Summary of the invention

[0014] In view of this, the object of the present invention is to provide an improved crane and an improved method for controlling the crane, which avoid the disadvantages of the prior art and develop the prior art in an advantageous manner. Preferably, an improved sway damping should be achieved in revolving tower cranes and jib cranes or other cranes, which better takes into account double sway movements in the case of extended suspension devices and loads suspended at a distance from the lifting hook.

[0015] Therefore, it is proposed to perform swing detection on the suspension device and / or directly on the load suspended at a distance from the lifting hook, and the swing sensor system on the suspension device and / or directly on the load suspended at a distance from the lifting hook is provided with an inertial detection device, which is mounted on the suspension device and / or directly on the load suspended at a distance from the lifting hook and provides acceleration signals and rotation rate signals representing the translational acceleration and rotation rate (Drehraten) of the suspension device and / or the load suspended at a distance from the lifting hook.

[0016] Such an inertial measuring unit (sometimes also referred to as IMU) mounted on a suspension device and / or directly on a load suspended at a distance from the lifting hook can include an acceleration and rotation rate sensor device for providing acceleration signals and rotation rate signals, which represent on the one hand a translational acceleration along different spatial axes and on the other hand a rotation rate or a gyroscope signal about different spatial axes. In this case, the rotation rate can be provided as a rotation speed, but in principle also a rotation acceleration or both can be provided.

[0017] Based on the acceleration signals and rotation rate signals of the inertial measurement device mounted directly on the suspension device or on the load fastened to the suspension device, and based on the position and / or deflection of the lifting hook or on the measurement signals which are able to characterize or identify the position and / or deflection of the lifting hook, the position or deflection of the load can be determined very accurately based on the double pendulum dynamics.

[0018] The lifting hook position and / or deflection can be determined in a known manner, for example by a sway sensor system having a camera in the area where the sling leaves the boom and / or a gyroscope on the sling and / or comprising another inertial measurement device on the lifting hook.

[0019] By means of an additional sway sensor on the suspension device and / or directly on the load suspended via the suspension device on the lifting hook and its inertial measuring device for providing acceleration signals and rotation rate signals of the load or the suspension device, the position and / or deflection of the load can be determined precisely even in the case of double pendulum movements without having to know exactly the length of the suspension device or the distance of the load from the lifting hook and the moments of inertia of the load and the suspension device relative to the lifting hook. In particular, this allows the position and / or deflection of the load to be determined precisely even if, as often happens in practice, loads of different weights are lifted during crane operation or suspension devices of different lengths are used or are tied to suspension devices of different lengths.

[0020] Advantageously, the inertial measurement device can be mounted on the load and / or the suspension device in a detachable and / or tool-free manner, wherein the fastening means for fastening the inertial measurement device can, for example, comprise magnetic means or elastic clamping means, so that the inertial measurement device can be fastened or clamped magnetically to the load and / or the suspension device in a simple manner. Other fastening means can also be used, for example, a vacuum suction button or a mechanically actuatable clamping means such as a clamping claw.

[0021] In particular, based on the double pendulum dynamics, an observer can be provided, for example in the form of a Kalman filter, in particular in the form of a nonlinear or so-called "unscented" Kalman filter, which can reliably and precisely determine the position and / or deflection of the load with the aid of the position and velocity signals of all drives and the position and / or deflection of the lifting hook, or with the aid of a sway sensor system for identifying the position and / or deflection of the lifting hook and signals of an additional sway sensor system (in the form of an inertial measurement device) on the load itself or on the suspension. In this case, for example, the length of the suspension and / or the distance between the load and the lifting hook and / or the deflection angle between the suspension and the vertical can be estimated, and the position of the load can be calculated therefrom.

[0022] Advantageously, the inertial measurement device can detect accelerations in three spatial axes and rotation rates about at least two spatial axes. The acceleration sensor device can be designed to operate in three axes, while the gyroscope sensor device can be designed to operate in at least two axes.

[0023] Advantageously, the inertial measurement device mounted on the suspension device and / or directly on the load suspended at a distance from the lifting hook can wirelessly transmit its acceleration signals and rotation rate signals and / or signals derived from these signals to a control and / or evaluation device, which can be mounted on a structural part of the crane or can also be arranged separately in the vicinity of the crane. In particular, the transmission can take place to a receiver, which can be mounted on the trolley and / or on the sling from which the sling extends. Advantageously, the transmission can take place, for example, via a Bluetooth or WLAN connection.

[0024] This wireless connection of the inertial measurement device also makes it very easy to retrofit the sway damper to existing cranes without requiring complex retrofitting measures. Basically, only the inertial measurement device must be mounted on the suspension device and / or directly on the load suspended at a distance from the lifting hook and on a receiver that communicates with it and transmits the signals to the control or regulating device.

[0025] Advantageously, the deflection of the load or of the suspension device which suspends the load on the lifting hook relative to the vertical can be determined in a two-stage or multi-stage process using the signals of the inertial measurement device. First, the inclination of the suspension device and / or the inclination of the load is determined, for example with the aid of a complementary filter or a directional filter, since the inclination does not necessarily correspond to the deflection of the lifting hook relative to the trolley or the suspension point and the deflection of the sling relative to the vertical, and then the expected deflection of the suspension device or the load suspended from the lifting hook relative to the vertical is determined based on the inclination of the suspension device and / or the load and its or their acceleration. The complementary filter or directional filter is for example Mahony R., Hamel T. and Pflimlin J. "Nonlinear Complementary Filters on the Special Othogonal Group", IEEE Transactions on Automatic Control, 2008, 53, 1203-1218 or Madgwick SOH, Harrison AJL and Vaidyanathan R. "Estimation of IMU and MARG orientation using a gradent descent algorithm", IEEE International Conference on Rehabilitation Robotics, 2011, 1-7. Since the inertial measurement device is fastened to the suspension device and / or directly to the load suspended at a distance from the lifting hook, the acceleration and rotation rate signals are influenced not only by the swinging movement of the cable but also by the dynamics of the suspension device which can tilt or swing relative to the cable.

[0026] In particular, an accurate estimation of the load sway angle and / or the load position can be achieved with a small number of calculation steps, which can then be used by the controller for active sway damping, in particular together with the lifting hook position and / or the sway angle of the lifting hook and / or the sling.

[0027] Advantageously, the inclination of the suspension device and / or of a load suspended at a distance from the lifting hook is first determined from the signals of the inertial measurement device with the aid of a complementary filter, which utilizes the different properties of the translational acceleration signal and the gyroscope signal of the inertial measurement device, wherein, alternatively or additionally, a Kalman filter can also be used to determine the inclination of the suspension device and / or of a load suspended at a distance from the lifting hook from the acceleration signal and the rotation rate signal.

[0028] Based on the determined inclination of the suspension device and / or of the load suspended at a distance from the lifting hook, the acceleration and the rotation rate of the load or the suspension device can then be determined in inertial coordinates.

[0029] In particular, the first determination device can include a complementary filter having a high-pass filter for the rotation rate signal of the inertial measurement device and a low-pass filter for the acceleration signal of the inertial measurement device or a signal derived therefrom, wherein the complementary filter can be designed to combine a rotation rate-based estimate of the inclination of the suspension device or the load based on the high-pass filtered rotation rate signal and an acceleration-based estimate of the inclination of the suspension device or the load based on the low-pass filtered acceleration signal, and to determine the inclination of the load handling device from the combined rotation rate-based estimate and acceleration-based estimate of the inclination of the load handling device.

[0030] The second determination device for determining the deflection of the suspension device or the load relative to the vertical line based on the determined inclination of the load carrier comprises a filter and / or an observer device, which takes into account the determined inclination of the load carrier as an input variable and determines the deflection of the suspension device or the load relative to the vertical line from the inertial acceleration at the suspension device or the load.

[0031] In particular, the filter and / or observer device may comprise a Kalman filter, in particular an extended or non-linear "unscented" Kalman filter.

[0032] As an alternative or in addition to such a Kalman filter, the second determination means may also comprise a calculation device for calculating the deflection of the sling and / or the load handling device relative to the vertical from a static relationship of accelerations, in particular from the quotient of horizontal inertial acceleration and gravitational acceleration.

[0033] Advantageously, a sway sensor system for detecting this component of the double pendulum movement can be provided on the upper part of the double pendulum (i.e. the sling and / or the lifting hook fastened thereto) so that the deflection of the sling and / or the lifting hook relative to the vertical and / or the lifting hook position can be determined based on the signals of the sway sensor system.

[0034] In particular, the sway sensor system for measuring the upper component of the double pendulum movement may include a gyroscope device capable of measuring the deflection of the sling. Such gyroscope devices associated with the sling are known per se and reference may be made, for example, to the above-mentioned document "A load position observer for cranes with gyroscope measurements" by Schaper Ulf et al.

[0035] As an alternative or in addition to such a gyroscopic device, the sway sensor system for detecting the swaying movement of the lifting hook can also have an inertial measuring device on the lifting hook which provides an acceleration signal and a rotation rate signal, which indicate the translational acceleration along different spatial axes on the one hand and the rotation rate or a gyroscopic signal about different spatial axes on the other hand and represent the translational acceleration and the rotation rate of the lifting hook. As the rotation rate, the rotation speed can be provided here, but in principle it is also possible to provide the rotation acceleration or both.

[0036] Evaluation of the acceleration and rotation rate signals of an IMU mounted on the lifting hook may be substantially similar to evaluation of the acceleration and rotation rate signals of an IMU mounted directly on the load or suspension as described above.

[0037] Advantageously, the detection device for detecting the position of the crane hook can also include an imaging sensor system, such as a camera, which looks essentially vertically downward from the suspension point of the sling (e.g., a trolley). The image evaluation device can identify the crane hook in the image provided by the imaging sensor system and determine its eccentricity or offset relative to the center of the image, which is a measure of the deflection of the crane hook relative to the vertical and thus characterizes the load swing. Alternatively or in addition, a gyroscopic sensor can detect the angle of departure from the crane boom and / or the hook relative to the vertical and provide this to the Kalman filter.

[0038] In the case of a lifting hook being articulatedly connected to the sling, the orientation of the lifting hook can correspond to the orientation of the suspension. It is therefore sufficient to mount an inertial measurement device only on the lifting hook and, since the inertial measurement device on the lifting hook provides acceleration signals and rotation rate signals which also characterize the deflection of the suspension and the load mounted on the suspension, a further inertial measurement device on the suspension and / or on the load is omitted. In this case, the position or the sway angle of the load and of the lifting hook itself can be determined by a single inertial measurement device on the lifting hook.

[0039] In this case, the tilt of the lifting hook and the suspension device or the downward swing angle of the double pendulum can be obtained directly from the estimation of the directional filter, which can be implemented as a complementary filter, for example. In this case, the deflection angle of the lifting hook and the suspension device mounted on the lifting hook relative to the vertical and the corresponding angular velocity do not represent the state of the system, but rather the input. In this case, the length of the suspension device can be estimated by a random walk method. Alternatively or in addition, the length of the suspension device can also be transmitted to the observer from the outside and / or via a higher-level software module.

[0040] The sway damping device can monitor the input commands of the crane operator during manual operation of the crane by actuating corresponding operating elements such as joysticks and, if necessary, ignore these input commands, in particular in the sense that if the crane movement specified by the crane operator has led to or will lead to a swaying of the lifting hook, the acceleration specified by the crane operator, for example too large, is reduced or a reverse movement is also automatically started. Advantageously, the controller module attempts to get as close as possible to the movement and movement profile desired by the crane operator in order to give the crane operator a sense of control and ignores manually input control signals only to the extent necessary in order to execute the desired crane movement as sway-free and vibration-free as possible. Alternatively or additionally, the speed of the load can be specified with one or more operating elements (e.g. one or more joysticks) instead of the speed of the drive, wherein the controller module or the control device controls the crane drive in such a way that the specification is achieved as well as possible, but at the same time the load does not start to sway.

[0041] Alternatively or additionally, the sway damping device can also be used for automated operation of a crane, in which a control device of the crane automatically moves a load handling device of the crane between at least two target points along a travel path in the sense of an autopilot. In such automated operation, in which a travel path determination module of the control device determines a desired travel path, for example in the sense of a path control, and an automatic travel control module of the control device controls a drive control or a drive device so that the lifting hook moves along a specific travel path, the sway damping device can intervene in the control of the drive control via the travel control module in order to move the lifting hook without swaying or to dampen swaying movements. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be explained in more detail below based on preferred exemplary embodiments and related drawings.

[0043] Figure 1 A schematic diagram of a revolving tower crane is shown, in which a sling extends from a trolley movable on a boom, a lifting hook is hinged to the sling, and a suspension device is suspended from the lifting hook, wherein the double pendulum movement that can result at different deflection angles of the sling and the suspension device is shown.

[0044] Figure 2 Shows Figure 1 Schematic diagram of a double pendulum and its articulation to the crane trolley, where the travel motion of the trolley, the change in length of the cable and the resulting swing angle are input.

[0045] Figure 3 The possible inclination of the lifting hook relative to the sling is shown.

[0046] Figure 4 A schematic diagram of a rotating tower crane and a double pendulum comprising a sling and a suspension device hinged on a lifting hook is shown, wherein the lifting hook is connected to the sling via an articulated connection and the deflection of the lifting hook corresponds to the deflection of the suspension device. DETAILED DESCRIPTION

[0047] like Figure 1 As shown, the crane 10 may be designed as a rotating tower crane. Figure 1 The rotating tower crane shown can, for example, comprise a tower 1 in a known manner, which carries a boom 2 which is counterbalanced by a counterarm 4 which can be provided with a counterweight. The boom 2 can be rotated together with the counterarm 4 by a rotating mechanism about a vertical rotation axis 5 which can be coaxial with the longitudinal axis of the tower. A trolley 6 can be moved on the boom 2 by a trolley drive, wherein a sling 7 with a lifting hook 8 fastened thereto extends from the trolley 6.

[0048] Likewise Figure 1As shown, the crane 2 (which can of course also be designed as a bridge crane or other crane) can include an electronic control device 3, which can have, for example, a control computer arranged on the crane itself. In this case, the control device 3 can control various actuators, hydraulic circuits, electric motors, drive devices and other working units on the corresponding construction machine. For example, in the crane shown, these can be the crane's lifting mechanism, rotation mechanism, trolley drive, (possibly present) boom luffing drive, etc.

[0049] In this case, the electronic control device 3 can communicate with a terminal device 9, which can be arranged at a control station or in a cab and can, for example, have the form of a touch screen and / or a joystick, knob, sliding switch and similar operating elements, so that on the one hand various information from the control computer 3 can be displayed on the terminal device 9, and conversely, control commands can be input into the control device 3 via the terminal device 9.

[0050] In particular, the control device 3 of the crane 10 may be designed to control the drive devices of the hoisting mechanism, the trolley and the rotating mechanism even when the sway damping device 30 detects a sway-related motion parameter.

[0051] To this end, the crane 10 may include a sway sensor system or detection device 60, which detects the slant of the suspension cable 7 and / or the deflection of the lifting hook 8 relative to a vertical line 62 extending through the suspension point of the lifting hook 8 (i.e., the trolley 6). In particular, the cable pulling angle β (see β) relative to the line of action of gravity (i.e., the vertical line 62) can be detected. Figure 1 ).

[0052] For this purpose, the sway sensor system 60 can have a camera 63 or another imaging sensor system mounted on the trolley 6 and looking vertically downward from the trolley 6, so that when the lifting hook 8 is not deflected, the representation of the lifting hook is located in the center of the image provided by the camera 63. However, if the lifting hook 8 deflects relative to the vertical 62, for example due to a sudden start of the trolley 6 or a sudden braking of the swivel mechanism, the representation of the lifting hook 8 moves out of the center of the camera image, which can be determined by the image evaluation device 61.

[0053] On the other hand, the tilting β of the sling or the deflection of the lifting hook relative to the vertical 62 can also be accomplished with the aid of an inertial measurement unit IMU, which is mounted on the lifting hook 8 and can transmit its measurement signals preferably wirelessly to a receiver on the trolley 6 (see Figure 1 ).

[0054] Furthermore, the swing sensor system 60 for detecting the “lower” part of the double pendulum movement (more precisely, the swinging movement of the suspension device 12 and the load 11 fastened thereto relative to the lifting hook 8) comprises an additional inertial measurement device IMU which can be mounted on the suspension device 12 or directly on the load 11. Figure 1 and 2 An additional inertial measurement device 66 on the suspension 12 and a further inertial measurement device 67 mounted directly on the load 11 are shown. By means of the at least one additional inertial measurement device 66 and 67, in particular the deflection angle The deflection angle represents the deflection of the suspension device 12 and the load 11 relative to the vertical 62 and thus relative to the lifting hook 8 .

[0055] Based on the deflection β and In particular, taking into account the direction and size of the deflection, the control device 3 can drive the rotary mechanism drive and the trolley drive with the aid of the sway damping device 30 so that the trolley 6 is again more or less directly above the load 11 and compensates for the double pendulum movement, or reduces or prevents the occurrence of a double pendulum movement in the first place.

[0056] In particular, based on the double pendulum dynamics, an observer can be determined, for example, in the form of a Kalman filter (in particular an “unscented” Kalman filter), which can reliably determine the position of the load 11 and / or its deflection β with the aid of the position of the lifting hook 8 or the measurements of the sensors (in the form of a camera 63 and / or an inertial measurement device 65) and the deflection β determined therefrom and an additional sway sensor system (in the form of an inertial measurement device 66 on the suspension device 12 and / or an inertial measurement device 67 on the load 11). In particular, the length of the suspension device 12 and thus the distance between the load 11 and the lifting hook 8 and the angle between the vertical line 62 and the suspension device 12 can also be estimated. The position of the load is calculated from this.

[0057] The basis of the observer is the mathematical description of the double pendulum. Figure 2 When looking at the model shown, the double pendulum dynamics can be derived with the aid of the Euler-Lagrange equations. For simplicity, only one oscillating surface and a crane without a swivel mechanism, e.g. a bridge crane, are considered below. However, the derivation can easily be extended to include another oscillating surface and other drives such as a pitch or swivel mechanism.

[0058] First, place the trolley in position s x (t), cable length l(t) and up and down swing angle β(t) and is defined as a function of time t, where for better readability, the time dependency is no longer specifically indicated by the term (t) in the following text. The positions of the hook and the load, and the corresponding velocities, can be defined based on these variables. The position of the hook can be expressed as:

[0059]

[0060] The position of the load can be expressed as:

[0061]

[0062] The corresponding speed can be expressed as:

[0063]

[0064] as well as

[0065]

[0066] Here, the parameter l A represents the length of the suspension. Depending on the design of the filter, this parameter can also be estimated online, as described later. Although the following accelerations are not required when deriving the double pendulum dynamics, they can be used later in the observer design:

[0067]

[0068] as well as

[0069]

[0070] With the help of kinetic energy and potential energy, the generalized coordinates can be derived by solving the Euler-Lagrange equation The double pendulum dynamics. The kinetic energy can be expressed as:

[0071]

[0072] Potential energy can be expressed as:

[0073] V=[0 g](m H r H +m L r L ) (8)

[0074] The Euler-Lagrange equation can be expressed as:

[0075]

[0076] Since the expression is long, the term and In the next step, the nonlinear system in state space is established as follows:

[0077]

[0078] The nonlinear system has the state enter Assume that the system noise w = N(0, Q) and the measurement noise v = N(0, R) are normally distributed on the covariance matrices Q and R. If the accelerations of the trolley and the cable are and If the inputs to the observer are not available directly from the controller or by measurement or estimation, they can also be determined by the PT-1 approximation, as described, for example, in WO 2019 / 007541. The output y depends on the available sensors. For example, in the case of IMUs (65) and (67) on the hook and the load, the acceleration In the case of a camera (63) and an IMU (67), it is suitable to use the hook swing angle and load acceleration determined by the camera as outputs. Alternatively or additionally, the rotation rate signal of the IMU may also be used as an output.

[0079] In this equation, in addition to the double pendulum dynamics, the system dynamics f also includes the random walk method (RandomWalk-Ansatz) for simultaneous estimation The suspension length at . A standard observer can now be designed for this system with the accelerations of the hook and the load in inertial coordinates as measured variables. For example, in the case of nonlinearities, an unscented or extended Kalman filter is suitable. Depending on the system, the desired accuracy and the available computing power, a simplified linearization in combination with a linear observer (e.g. a simple Kalman filter) may also be advantageous.

[0080] The following example uses the hook and load acceleration as outputs. The unscented Kalman filter process. First, at time step k, the expected value of the system state x must be used The covariance matrix P, design parameter κ and system state n = 5 are used to determine the appropriate Sigma point χ = ​​[X0,…,X 2n ] and the matching weighting factor W = [W0,…,W 2n ], their equations are as follows:

[0081]

[0082] The roots of the matrix in equation (11) are not well defined and must be determined by Cholesky decomposition. According to this method, the i-th column or i-th row is used in equation (11). Then, the sigma point of the next sampling step k+1 is predicted by applying the system equation (10):

[0083] χ i (k+1|k)=f(χ i (k),u(k)) (12)

[0084] The expected value of the forecast is given by the following equation:

[0085]

[0086] Then, the estimation error covariance matrix is ​​obtained using the covariance of the process noise Q to give:

[0087]

[0088] Now, we can use P(k+1|k) and Instead of P(k) and To determine the new sigma point χ i (k+1|k) and weight W i The sigma point predicted in this way can now be entered into the measuring range with the aid of the initial equation (10):

[0089] Z i (k+1|k)=h(χ i (k+1|k),u(k)) (15)

[0090] The measurement results can therefore be predicted by forming an expected value:

[0091]

[0092] Then, the innovation covariance matrix is ​​determined with the help of the covariance matrix of the measurement noise R:

[0093]

[0094] The Kalman matrix can be determined using the innovation covariance matrix and the cross-correlation matrix, where the cross-correlation matrix is:

[0095]

[0096] The Kalman matrix is:

[0097] K(k+1)=T(k+1)S -1(k+1) (19)

[0098] And together with the measurement value z(k+1), an innovation of the expected value and the estimated error covariance is performed:

[0099]

[0100] The estimated error covariance is:

[0101] P(k+1|k+1)=P(k+1|k)-K(k+1)S(k+1)K(k+1) T (twenty one)

[0102] Finally, the estimated state expected value can be used The position and load of the hook are determined by equations (1) and (2).

[0103] As mentioned at the beginning of the filter description, the measured values ​​z(k+1) used in equation (20) can be the accelerations of the hook and the load and However, the measured accelerations of the IMU (65) and (67) cannot usually be used directly, because the IMU is mounted at an angle or the crane hook may be tilted at an angle ε. β Tilt (see Figure 3 ). Therefore, the measured acceleration must be converted into an inertial system. An orientation filter (Orientierungsfilter) which can be designed as an EKF or a complementary filter is suitable for this purpose. For example, a method using a complementary filter is described in WO 2019 / 007541, which will be briefly outlined again here for the sake of completeness.

[0104] The IMU measures all signals in the co-moving, co-rotating fixed coordinate system of the crane hook, which is marked with a footnote K, while vectors in inertial coordinates are marked with an I or remain completely unfootnoteed. Once ∈ β , the measured acceleration a in the crane hook coordinates can be converted to K =[a K,x ,a K,z ] T Convert to inertial coordinates a I :

[0105]

[0106] The inertial acceleration can then be used as the measured variable of the observer z or as the output y of the system (10). β The tilt angle can be estimated by using a simple integrator model, which can be expressed as:

[0107]

[0108] However, in the case of measuring the rotation rate or the tilt speed with a gyroscope, the gyroscope signal has a time-variable offset and is superimposed with measurement noise, so that the method is not effective. Therefore, it is advantageous to use a directional filter.

[0109] Therefore, an accelerometer is used to provide the angle ∈ by evaluating the gravitational acceleration constant (which appears in the low-frequency signal) β The gravitational acceleration is known in inertial coordinates as:

[0110] g I =[0,-g] T (twenty four)

[0111] And can be converted into lifting hook coordinates:

[0112] g K =-g[-sin(∈ β )cos(∈ β )] T (25)

[0113] The measured acceleration is the sum of (103) and (112):

[0114]

[0115] Here, g K The negative sign of is due to the fact that the acceleration due to gravity is measured as a fictitious upward acceleration due to the sensor principle. All components of are typically significantly smaller than g and swing around zero, so using a low-pass filter with a sufficiently low cutoff frequency allows the following approximation:

[0116] a K ≈-g K (27)

[0117] If the x component a K,x Divide by the z component a K,z , then the reference tilt angle at low frequency is obtained:

[0118]

[0119] The simple structure of equations (23) and (28) allows a variety of filters to be used to estimate the direction. One option is a complementary filter, whose frequency characteristics can be set by selecting the high-pass and low-pass transfer functions.

[0120] Use G hp (s) for gyro signal ωβ High pass filtering is performed to obtain the rotation rate without offset And after integration, the first tilt angle estimate ∈ β,ω Another estimate ∈ β,a From equation (28) based on the acceleration sensor. In particular, a simple high-pass filter with the following transfer function and very low cut-off frequency ω0 can first be applied to the gyroscope signal ω β In order to eliminate the constant measurement deviation, the transfer function is:

[0121]

[0122] The integral gives the gyroscope-based tilt angle estimate ∈ β,ω , the tilt angle estimate is relatively accurate for high frequencies, but relatively inaccurate for low frequencies. The basic idea of ​​the complementary filter is to convert ∈ β,ω and ∈ β,a Add or combine, where, by using a high-pass filter, ∈ β,ω The high frequencies of are given higher weights, and since (28) shows a good estimate of the low frequencies, by using a low-pass filter, ∈ β,a The low frequencies are given higher weights, and the low-pass filter is:

[0123]

[0124] The transfer function can be chosen as a simple first order filter, where the cutoff frequency ω0 is chosen to be below the swing frequency. Since the following equation applies to all frequencies, there is no error scaling ∈ β Estimates.

[0125] G hp (s)+G lp (s)=1 (31)

[0126] Based on the estimated lifting hook direction, it can be obtained from a K Determine the inertial acceleration a of the lifting hook from the measured value of I , that is, by using (22) to determine the inertial acceleration a I , which allows the design of an observer based on the double pendulum dynamics (10) and the acceleration measurement of the rotation, which can be expressed as:

[0127]

[0128] Although both components of this equation can be used equally to estimate the roll angle, good results can be obtained using only the x component, which is independent of g.

[0129] The evaluation of the inertial measurement devices 65 and 66 or 67 mounted on the suspension 12 or directly on the load 11 can be performed in a similar manner as just described above. To avoid repetitions, reference is made to the above embodiments.

[0130] Thus, even during a double pendulum movement, the position of the load 11 can be determined precisely by means of an additional inertial measurement device 66 or 67 on the suspension 12 or on the load 11 .

[0131] like Figure 4 As shown, depending on the type of crane and the design of the hook block or the lifting hook, the connection between the sling and the hook block can be modeled by a pivot joint (70) and at the same time the connection between the load suspension device and the lifting hook is assumed to be fixed. In this case, the inclination of the lifting hook ∈ β Corresponding to the downward swing angle Thus, in this case with a single IMU on the lifting hook, the position or sway angle of the lifting hook and the length of the suspension device as well as the position or sway angle of the load itself can be determined. If necessary, the mounting angle of the IMU must also be additionally taken into account if the axes of the IMU are not perfectly aligned.

[0132] Tilt∈ β or down swing angle It is derived directly from the estimation of the directional filter, which can be realized, for example, as described above, by means of a complementary filter. Depending on the quality of the directional filter, two implementations are conceivable for the observer.

[0133] If the tilt ∈ estimated by the direction filter β is inaccurate or noisy, it is appropriate to use a state The entire double pendulum model (10). In this case, in addition to the hook acceleration, the model The output also includes the tilt of the hook and the hook's rotation rate corresponding to the downward swing angular velocity and is used as the measured variable z of the observer.

[0134] If the quality of the directional filter is high enough, the observer can be reduced. In this case, the state to be estimated Reduce to upper swing angle β, swing angular velocity and the length of the suspension device l A In this observation, the down swing angle and angular velocity is not the state, but the input to the system. Therefore, we get In this case, the output of the model is The acceleration of the hook can be included and used as the observer's measured value z. In this respect, it should be pointed out again that the rotation rate of the hook in the inertial system can also be used in addition or as an alternative.

[0135] In this case, the length of the suspension is also estimated by a random walk method. Alternatively, the length can also be transferred to the observer directly from the outside or from a superordinate software module or by the user.

[0136] In an advantageous refinement example, the method and the observer shown for describing the dynamics of the double pendulum can be combined with a structural model of the crane (for example as described in WO 2019 / 007541). The states determined in this way can be used to stabilize and suppress unwanted swinging movements. For this purpose, nonlinear controls can be designed, for example model predictive control (MPC). For a simpler illustration, a crane with a swinging surface, for example a bridge crane, is also used here. However, the method can easily be extended to other vibration surfaces, for example rotating mechanisms and structural elasticity.

[0137] In terms of model predictive control, the behavior of the crane is predicted within a certain period of time according to a mathematical model, and the adjustment variables are changed so that the cost function J describing the control objective is minimized.

[0138] For this purpose, a mathematical model of the crane is required. However, this mathematical model must also take into account the drive dynamics in addition to the swing dynamics and any structural elasticity. Assuming the presence of fast overlapping speed control of the inverter, the drive dynamics of the overhead crane considered for simplification are:

[0139]

[0140] Among them, the status And enter The functions f1(x,u) and f2(x,u) describe the acceleration of the double swing angle similar to the system (10). In addition, the structural dynamics of the crane should also be considered in (33).

[0141] A possible design of the cost function is:

[0142]

[0143] Among them, for And u des =[0,0] T The cost function provides the penalty for the swing angle, the swing angular velocity, and the trolley speed and the lifting speed relative to the desired target speed based on the weighted matrices Q and R. and Here, the tilde indicates that no target values ​​are specified for the trolley position and the lifting cable length. Alternatively, other equations can also be considered that penalize deviations of, for example, the load or hook speed from a specified value. Equations that penalize position deviations of the hook, load or individual drives from the target position can also be used. On this basis, the dynamic optimization problem can be expressed as:

[0144]

[0145] This is solved numerically at each sampling step, for example, by means of common software tools such as ACADO or GRAMPC. The first part of the controlled variable trajectory u(t) is used as input and, after integration, is passed to the converter of the drive as the target velocity. In addition to the system dynamics, the optimization problem (35) also directly includes the possible time-varying constraints of the drive in the form of maximum and minimum accelerations in the controlled variable constraints. and and including the maximum and minimum speed and position in the state limits and This is a particular advantage of MPC.

[0146] However, MPC requires a lot of computational effort, so as an alternative to nonlinear control based on the linearization of the model (33), a linear controller with gain scheduling can also be determined, for example in the form of linear quadratic control (LQR). For example, as shown in WO 2019 / 007541 for a simple pendulum, this control can be advantageously combined with trajectory generation and feedforward control to form a two-degree-of-freedom control system.

Claims

1. A crane comprising: A sling (7) extends from the boom (2) and carries a lifting hook (8), wherein: A suspension device (12) is mounted on the lifting hook (8), a load (11) is fixed on the suspension device, and the load is suspended by the suspension device (12) in a manner spaced apart from the lifting hook (8); a determination device (60) for determining the position and / or deflection of the load (11); and an electronic control device (3) for controlling a drive device for moving crane elements and transferring the lifting hook (8) as a function of the detected position and / or deflection of the load (11), Characterized in that the determining device (60) has: first determining means (63; 65) for determining the position and / or deflection of the lifting hook (8); an inertial measurement device (66, 67) mounted on the suspension device (12) and / or on the load (11) and having acceleration and rotation rate sensor means for providing acceleration signals and rotation rate signals; and Second determination means, for determining and / or estimating the deflection and / or the position of the load (11) based on the acceleration signal and the rotation rate signal of the inertial measurement device (66, 67) mounted on the suspension device (12) and / or on the load (11), and based on the signal of the first determination means (63, 65) for characterizing the position and / or deflection of the lifting hook (8).

2. The crane according to claim 1, wherein: The crane is a revolving tower crane or a jib crane.

3. The crane according to claim 1, wherein: The inertial measurement device (66, 67) on the suspension device (12) and / or on the load (11) has a wireless communication module for wirelessly transmitting measurement signals and / or signals derived from the measurement signals to a receiver, wherein the communication module and the receiver can be connected to each other via a Bluetooth or WLAN connection, and the receiver is arranged on a trolley (6) from which the sling (7) extends.

4. The crane according to any one of claims 1 to 3, wherein: The inertial measurement device (66, 67) on the suspension device (12) and / or on the load (11) has an energy store in the form of a rechargeable battery.

5. The crane according to any one of claims 1 to 3, wherein: The inertial measurement device (66, 67) on the suspension device (12) and / or on the load (11) has a detachable fastening device, which is in the form of a magnetic device and / or a clamping device for detachable fastening on the load (11) and / or on the suspension device (12).

6. The crane according to claim 5, wherein: The inertial measurement device is fixedly integrated as a chain link in the suspension device (12).

7. The crane according to any one of claims 1 to 3, wherein: The suspension device (12) comprises at least one suspension rope and / or suspension chain.

8. The crane according to any one of claims 1 to 3, wherein: The second determination device comprises a filter and / or an observer device which takes into account the determined deflection and / or tilt ε of the suspension device (12) and / or the load (11). φ As input variables, a deflection φ of the suspension device (12) and / or the load (11) relative to a vertical line (62) is determined as a function of the inertial acceleration at the load (11) and / or the suspension device (12).

9. The crane according to claim 8, wherein: The filter and / or observer arrangement comprises an extended and / or unscented Kalman filter.

10. The crane according to any one of claims 1 to 3, wherein: The first determination device for determining the position and / or deflection of the lifting hook (8) comprises an imaging sensor system which looks downward essentially vertically on the trolley (6), wherein an image evaluation device (61) is provided for evaluating the position of the lifting hook (8) in the image provided by the imaging sensor system and for determining the deflection β of the lifting hook (8) and / or the sling (7) and / or the deflection speed relative to the vertical (62).

11. The crane according to any one of claims 1 to 3, wherein: The first determination means comprises an inertial measurement device mounted on the lifting hook (8), the inertial measurement device mounted on the lifting hook having acceleration and rotation rate sensor means for providing acceleration signals and rotation rate signals characterizing the translational acceleration and rotation rate of the lifting hook (8).

12. The crane according to any one of claims 1 to 3, wherein: The lifting hook (8) is connected to the sling (7) in an articulated manner so that the deflection of the lifting hook (8) corresponds to the deflection of the suspension device (12), wherein an inertial measurement device having an acceleration and rotation rate sensor device for providing an acceleration signal and a rotation rate signal is arranged on the lifting hook (8), and the determination device is configured to determine and / or estimate the deflection and / or position of the load (11) suspended on the suspension device (12) based on the acceleration signal and the rotation rate signal of the inertial measurement device on the lifting hook (8).

13. The crane according to claim 12, wherein: The inertial measurement device is only provided on the lifting hook (8), and the deflection and / or position of the load (11) suspended on the suspension device (12) is determined and / or estimated without inertial measurement devices on the suspension device (12) and the load (11).

14. The crane according to claim 12, wherein: The length of the suspension device (12) is estimated and / or input and / or transmitted via an external interface, wherein the deflection (φ) of the suspension device (12) and / or the load (11) relative to the vertical (62) is determined based on the estimation of a directional filter configured as a complementary filter.

15. A method for controlling a crane, wherein a suspension device (12) to which a load (11) is fixed is mounted on a lifting hook (8) of the crane, the lifting hook being mounted on a sling (7), in, The position and / or deflection of the load (11) is determined by a determination device (60) and a drive device for moving a crane element is controlled by an electronic control device (3) as a function of the determined position and / or deflection of the load, Characterized in that the position and / or deflection of the lifting hook (8) is determined by means of a first determination device (63, 65), and an acceleration signal and a rotation rate signal indicating a translational acceleration and a rotation rate on the suspension device (12) and / or on the load (11) are provided by means of at least one inertial measurement device (66, 67) having an acceleration and rotation rate sensor device mounted on the suspension device (12) and / or on the load (11), and the acceleration signal and the rotation rate signal are transmitted wirelessly to the control device (3), Therein, the position and / or the deflection φ of the load (11) is determined based on the acceleration signal and the rotation rate signal of the inertial measurement device (66, 67) and the position and / or the deflection β of the lifting hook (8) determined by the first determination device.

16. The method according to claim 15, wherein: The crane is a revolving tower crane or a jib crane.

17. The method according to claim 15, wherein: A deflection φ of the load (11) and / or the suspension device (12) relative to a vertical line (62) is determined by a filter and / or an observer device based on the inertial acceleration at the load (11) and / or the suspension device (12), and the determined deflection of the load (11) and / or the suspension device (12) is provided to the filter and / or the observer device as an input variable.

18. The method according to any one of claims 15 to 17, wherein: The acceleration signal indicating the translational acceleration on the load (11) and / or the suspension device (12) is determined relative to three spatial axes, and the rotation rate signal indicating the rotation rate on the load (11) and / or the suspension device (12) is detected relative to at least two spatial axes.

19. The method according to any one of claims 15 to 17, wherein: The lifting hook (8) is connected to the sling (7) in an articulated manner and is deflected relative to the vertical (62) at the same swing angle (φ) as the suspension device (12), wherein an acceleration signal and a rotation rate signal indicating the translational acceleration and the rotation rate on the lifting hook (8) are provided by an inertial measurement device having an acceleration and rotation rate sensor device installed on the lifting hook (8), and the acceleration signal and the rotation rate signal are wirelessly transmitted to the control device (3), wherein the position and / or deflection (φ) of the suspension device (12) and the load (11) is determined based on the acceleration signal and the rotation rate signal of the inertial measurement device on the lifting hook (8).

Images