EP2361216B1 - Device for controlling the movement of a load suspended from a crane - Google Patents

Abstract

A device for controlling movement of a load suspended by cables from a hook point that is rotatable about a vertical axis and movable translationally along an axis of translation, the movement of rotation generating a first or sway angle of the load relative to the axis of translation. The device calculates the first or sway angle and a speed of the first or sway angle, the only input variables used being the length of the cables, the distance between the axis of rotation and the hook point, and the speed of rotation of the hook point, while the acceleration of the first or sway angle is used as an internal variable.

Description

The present invention relates to a regulating device and a method for regulating the movement of a load suspended by cables to a hoist, this hoisting apparatus being capable of driving the load in a rotational movement.

The lifting gear concerned include in particular different types of tower cranes or jib cranes. These cranes have an arrow that hangs on top of a vertical mast. The boom has a point of attachment to which the load is suspended by suspension cables. They have the distinction of making a first movement which is a rotational movement of the arrow about a vertical axis of rotation Z which is generally centered on the mast of the crane (rotation or slewing movement).

Furthermore, these cranes perform a second movement which is a linear movement of the point of attachment along the arrow, this second movement being called translation movement in the present document. In some cranes, the point of attachment of the load is a carriage (trolley) which is movable in translation on rails, the translational movement then being performed along the horizontal axis X of the arrow (trolley movement). Other cranes have an arrow which is liftable (luffing jib) or articulated (jack-knife jib) and at the end of which is arranged the point of attachment of the load. The lifting or articulation of the arrow then creates the translational movement of the point of attachment.

In addition, the cranes always include a load lifting device which is associated with the suspension cables whose length is variable so as to move the load vertically in a third movement called hoisting movement.

The handling of a load by a lifting vehicle causes swaying of this load that it is obviously desirable to damp to perform smoothly and safely the transfer of the load and this, in a shortest period of time possible. In the case of a crane, a first swing (or first swing) is generated by the rotational movement about the vertical axis of rotation Z. A second swing (or second swing) is also generated by the acceleration / deceleration of the translational movement along the X translation axis.

Unlike a dangling due to a linear movement, the peculiarity of a dangling due to a rotational movement is that this dangling has a component that is generated by the centrifugal force of the load during the rotational movement, this force tending to move the load away from the rotational zone. It is therefore not possible to remove the first ballant by acting only on the controls of this rotational movement. In addition, the first ballant has the particularity to remain present as soon as the speed of rotation is non-zero, even when the acceleration or deceleration of the rotational movement is zero.

There are already several solutions to automatically reduce the angle of the balloon generated by a translational movement of a load suspended along a horizontal axis, particularly in documents FR2698344 , FR2775678 , US5443566 . However none of these documents deals with an anti-dangling device capable of automatically regulating the angle of the balloon generated by a rotational movement of the load around a vertical axis of rotation. The article of Sadati et al ("Design of a Gain-Scheduling Anti-Swing Controller for Tower Cranes Using Fuzzy Clustering Techniques", Comp.Int.Mod., Cont.and Autom., 2006, ISBN: 978-0-7695-2791- 4 ) discloses a device according to the preamble of claim 1.

This is why the invention aims to control the oscillations of a load suspended from a crane, using a device and a simple process, fast and easy to implement. It makes it possible to minimize the measurements or the information taken which are necessary to carry out the control and the control of the ballad of a load.

For this purpose, the invention describes a device for regulating the movement of a load suspended by suspension cables at a point of attachment of a hoist, the point of attachment being able to perform a rotational movement. around a vertical axis of rotation and a translational movement along a translation axis, the rotational movement generating a first swing angle of the load along the axis of translation. The regulating device comprises means for calculating the first swaying angle and a speed of the first swaying angle, using as only input variables information representative of a length of the suspension cables, information representative of a distance between the axis of rotation and the point of attachment and information representative of a speed of rotation of the point of attachment, and using as an internal variable an acceleration of the first angle of dangling. The calculating means determines the first swing angle and the speed of the first swing angle using an iterative process using the acceleration of the first swing angle.

According to one characteristic, the calculation means determine the first swing angle of the load while also taking into account the translational movement effected by the point of attachment along the axis of translation.

According to another characteristic, the information representative of the rotation speed of the point of attachment is determined by using a speed reference which is supplied to a speed variator controlling the rotational movement of the point of attachment. Alternatively, the information representative of the rotation speed of the point of attachment is determined by using a speed estimation which is developed by a variable speed drive controlling the rotational movement of the point of attachment.

According to another characteristic, the regulating device calculates an offset value of the first dangling angle which is a function of the rotation speed of the point of attachment and delivers a first correction signal of the speed of the translational movement of the d-point. grip which takes into account the offset value. The first correction signal is proportional to the difference between the first swing angle and the offset value and is proportional to the speed of the first swing angle.

According to another characteristic, the first correction signal is added to a speed reference to provide a speed reference of the translation movement of the point of attachment, the correction signal being calculated by applying a correction coefficient to the difference between the first swing angle (Θx) and the offset value and the speed of the first swing angle. The correction coefficients may be variable depending on the length of the suspension cables.

According to another characteristic, the calculating means calculate a second angle of the load on a tangential axis perpendicular to the translation axis and a speed of the second swing angle, using an iterative process and using as only input variables the information representative of the length, the information representative of the distance and the information representative of the speed of rotation, and using as an internal variable an acceleration of the second dangling angle.

The invention also claims an automation system for controlling the movement of a load suspended by suspension cables at a point of attachment of a hoist and comprising such a control device. Similarly, the invention claims a method for controlling the movement of a suspended load which is implemented in such a control device.

• la figure 1 montre un exemple d'un engin de levage, de type grue, comportant un mouvement de rotation autour d'un axe vertical,
• la figure 2 schématise les angles de ballant d'une charge suspendue à un point d'accroche dans un tel engin de levage,
• la figure 3 représente un schéma simplifié d'un dispositif de régulation du déplacement d'une charge conforme à l'invention.

Other features and advantages will appear in the detailed description which follows with reference to an embodiment given by way of example and represented by the appended drawings in which:

• the figure 1 shows an example of a hoist, crane type, having a rotational movement about a vertical axis,
• the figure 2 schematizes the dangling angles of a load suspended at a point of attachment in such a hoist,
• the figure 3 represents a simplified diagram of a device for regulating the displacement of a load according to the invention.

The device for regulating the displacement of a suspended load according to the invention can be implemented in a hoist device comprising a rotational movement of the load, such as a crane or the like. The example of figure 1 shows a crane 5 which has a vertical mast and a substantially horizontal arrow 6. The arrow 6 comprises a point of attachment 10, which can be a movable carriage as in the example of the figure 1 . The arrow 6 can rotate about a vertical axis of rotation Z passing through the vertical mast of the crane 5. The attachment point 10 is movable along the arrow 6 to perform a translational movement according to a X translation axis. The translation axis X thus crosses the axis of rotation Z at a point O (see figure 2 ) and passes through the point of attachment 10. In the example shown, the translation axis X is horizontal, but some cranes have an arrow 6 having a non-zero angle relative to the horizontal.

Furthermore, the crane 5 can perform a vertical lifting movement to raise and lower a load 15 suspended by one or more suspension cables 14 which pass through the point of attachment 10 and at the end of which is associated with a suspension member of the load 15 to move.

With reference to the figure 2 , the point of attachment 10 is situated at a distance R from the axis of rotation Z (represented by the point O of the figure 2 ), this distance R varying as the point of attachment 10 moves along the axis of translation X. Under the action of the lifting movement, the load 15 obviously has a suspension height varying according to the length L of the cables This suspension suspension height of the load will subsequently be assimilated to the length of the cables L, to which an offset could be added possibly representing the distance between the low end of the cables 14 and the load 15 (materialized, for example by its center of gravity).

During the rotational movement, the load 15 moves along a virtual vertical cylinder centered on the vertical axis Z and radius R, ignoring the ballant. At any time, the rotational movement of the point of attachment 10 is therefore carried out along a moving tangential horizontal axis Y which is always perpendicular to the translation axis X and tangent with respect to the vertical cylinder.

When the hook point 10 rotates, the load 15 takes a pendulous swinging motion which is defined by a swing angle having two orthogonal components. A first component forms the first dangling angle noted Θx and corresponds to the projection of the ballant on the translation axis X. A second component forms the second dangling angle noted Θy and corresponds to the projection of the ballant on the tangential axis Y In addition, when the attachment point 10 performs a translational movement, the load 15 also takes a pendulum movement with a swinging angle along the translation axis X only, which is therefore added to the first swing angle Θx defined above.

The translation movement along the X axis is performed by means of a translation motor Mx driven by a variable speed drive Dx which receives a speed reference Vx _ref (see figure 3 ). Similarly, the rotational movement about the vertical axis Z is performed by means of a rotation motor My driven by a variable speed drive Dy which receives an angular speed reference Vy _ref . The lifting movement along the Z axis is performed by means of a hoisting motor not shown in the figures which makes it possible to wind and unwind the suspension cables. This hoist motor could be placed on the point of attachment 10.

The translation or rotation movement is controlled by the driver of the crane 5, this conductor providing a translation speed reference signal Vcx, respectively a rotation speed reference signal Vcy, using, for example, combinator (s) - of the joystick type, as indicated on the figure 3 . Nevertheless, in certain applications where the lifting gear would be controlled automatically, it could also be envisaged that the speed instructions Vcx, Vcy come directly from automation equipment.

Moreover, unlike linear movements, a rotational movement generates a ballant whose angle has components Θx and Θy nonzero in the two perpendicular axes, respectively X and Y. The second component Θy along the Y axis is generated by the acceleration / deceleration of the point of attachment and can be fought by acting on the control of the rotational movement. By cons, the first component Θx along the X axis is generated by the centrifugal force which causes a displacement of the load 15 which is not directed in the tangential plane YZ, but which is directed along a perpendicular plane XZ. This first component Θx can not therefore be fought by acting on the control of the rotational movement, but involves also acting on the control of the translational movement along the axis X.

In addition, the centrifugal force causes the load to move along the X axis, even when the rotational movement is at constant speed (i.e., at zero acceleration / deceleration).

The object of the invention is therefore to assist in the control of a hoist 5 capable of performing a translational movement and a rotational movement of the point of attachment 10, these two movements can obviously be performed simultaneously. Similarly, the translation and rotation movements can be performed simultaneously with a lifting movement of the load 15 along the axis Z.

The nature of the dangling generated by the rotation and the interaction between the different movements complicates the control of the dangling and the regulation of the displacement of the suspended load 15.

The invention makes it possible to simply and automatically damp the ballant along the X axis and along the Y axis during the displacement of the load 15, in a manner that is transparent to the driver of the machine. Advantageously, the invention does not require a learning phase and does not require measurement of the swing angle Θx and / or Θy, measurement of the motor current or the motor torque which can prove to be expensive and longer to enforce.

With reference to the figure 3 a regulating device 20 is intended to damp the oscillating movement of the load 15 during its displacement in rotation and / or in translation, this displacement obviously being able to be performed at the same time as a lifting movement of the load 15 .

The regulating device 20 comprises means for determining information representative of the length L of the suspension cables. These determination means comprise, for example, a sensor or encoder associated with the lifting motor shaft or with the winding drum of the cables. Other means for determining the length L are conceivable: for example, several limit switches distributed over the entire race of the cables, the length L being then determined by predetermined bearing values as a function of the triggering of these limit switches. . This solution is nevertheless less precise obviously.

• Selon une première variante, la distance R est obtenue à l'aide d'un capteur qui peut être un codeur rotatif associé à l'arbre du moteur de translation Mx ou au tambour d'enroulement des câbles, ou qui peut être un codeur absolu, par un exemple un codeur linéaire de type potentiomètre le long de la flèche 6.
• Selon une deuxième variante, la distance R est obtenue par intégration à partir d'une mesure de la vitesse de référence Vx_ref du mouvement de translation, puis par intégration de cette vitesse de référence. Cette vitesse de référence Vx_ref est facilement disponible car elle est en effet utilisée par le variateur Dx en charge de piloter le moteur de translation Mx. Un ou plusieurs détecteurs, de type fin de course ou détecteur de proximité, peuvent en plus être utiles pour fournir des valeurs de réinitialisation de R.
• Selon une troisième variante, la distance R peut également être obtenue à l'aide de plusieurs détecteurs répartis sur l'ensemble de la course le long de la flèche 6, la distance R étant alors déterminée par des valeurs paliers prédéterminées en fonction du déclenchement de ces fins de course. Cette solution est néanmoins moins précise évidemment.

The regulating device 20 comprises means for determining information representative of the distance R between the point of attachment 10 and the axis of rotation Z. Various determination means are possible:

• According to a first variant, the distance R is obtained by means of a sensor which may be a rotary encoder associated with the shaft of the translation motor Mx or with the winding drum of the cables, or which may be an absolute encoder , for example, a linear potentiometer type encoder along the arrow 6.
• According to a second variant, the distance R is obtained by integration from a measurement of the reference speed Vx _ref of the translational movement, then by integration of this reference speed. This reference speed Vx _ref is easily available because it is indeed used by the Dx drive in charge of control the translation motor Mx. One or more detectors, of end-of-travel type or proximity detector, may additionally be useful for providing resetting values of R.
• According to a third variant, the distance R can also be obtained using several detectors distributed over the entire stroke along the arrow 6, the distance R being then determined by predetermined bearing values as a function of the triggering of these ends of the race. This solution is nevertheless less precise obviously.

• Selon une première variante, la vitesse de rotation Vy est obtenue par une mesure de la vitesse réelle de rotation du point d'accroche 10. Cette solution nécessite cependant l'utilisation d'un capteur de vitesse ou de déplacement.
• Selon une deuxième variante, la vitesse de rotation Vy est obtenue directement par la référence de vitesse Vy_ref qui est fournie en entrée du variateur Dy en charge de piloter le moteur de rotation My. On suppose dans ce cas que le variateur Dy s'assure du suivi de la référence vitesse avec une grande rapidité. Cette solution est très simple à mettre en oeuvre car la référence de vitesse Vy_ref est facilement disponible.
• Selon une troisième variante, la vitesse de rotation Vy est obtenue par une estimation de vitesse élaborée dans le variateur de vitesse Dy en charge de piloter le moteur My. Dans certains cas, cette estimation de vitesse est en effet plus proche de la vitesse réelle que la référence de vitesse Vy_ref, à cause de phénomènes tels que écart de suivi de rampe ou phénomènes mécaniques. Cette solution peut donc être intéressante notamment pour une application utilisant un moteur conique. Le paramètre interne au variateur d'estimation de vitesse est souvent disponible sur une sortie analogique du variateur.

The regulating device 20 also comprises means for determining information representative of the speed of rotation Vy of the point of attachment 10. Various means of determination are possible:

• According to a first variant, the speed of rotation Vy is obtained by measuring the actual rotation speed of the point of attachment 10. This solution however requires the use of a speed or displacement sensor.
• According to a second variant, the rotation speed Vy is obtained directly by the speed reference Vy _ref which is supplied at the input of the drive Dy in charge of controlling the rotation motor My. It is assumed in this case that the drive Dy ensures the tracking of the speed reference with great speed. This solution is very simple to implement because the speed reference Vy _ref is easily available.
• According to a third variant, the speed of rotation Vy is obtained by a speed estimation elaborated in the variable speed drive Dy in charge of controlling the motor My. In some cases, this speed estimate is indeed closer to the actual speed than the speed reference Vy _ref , because of phenomena such as ramp tracking deviation or mechanical phenomena. This solution can therefore be of interest especially for an application using a conical motor. The parameter internal to the speed estimation drive is often available on an analog output of the drive.

The regulation device 20 comprises an estimator module 21 connected to a correction module 22. The estimator module 21 receives as input the information representative of the length L of the cables, the distance R and the speed of rotation Vy and comprises means for calculating which compute in real time the first swinging angle Θx and the speed (or variation) Θ'x of this first angle Θx, as well as the second swing angle Θy and the speed (or variation) Θ'y of this second angle .theta.y. The estimator module 21 then transmits these calculated values to the correction module 22 which calculates and outputs a first correction signal ΔVy which is added to the instruction of speed Vcy of the rotational movement, and a second correction signal ΔVx which is added to the speed reference Vcx of the translational movement.

1. a) L*Θ"x = - g*sinΘx - V'x*cosΘx + Vy²*(R + L*sinΘx)*cosΘx + (Vz - K_f)*Θ'x
2. b) L*Θ"y = - g*sinΘy - V'y*R*cosΘy + Vy²*L*sinΘy*cosΘy + (Vz - K_f)*Θ'y
   dans lequel :
   • Θx représente le premier angle de ballant de la charge selon l'axe X,
   • Θ'x représente la vitesse de l'angle de ballant Θx,
   • Θ"x représente l'accélération de l'angle de ballant Θx,
   • Θy représente le second angle de ballant de la charge selon l'axe Y,
   • Θ'y représente la vitesse de l'angle de ballant Θy,
   • Θ"y représente l'accélération de l'angle de ballant Θy,
   • L représente la longueur des câbles,
   • R représente la distance entre le point d'accroche des câbles et l'axe de rotation Z,
   • Vz représente la vitesse du mouvement de levage, calculée comme étant la dérivée de la longueur L,
   • Vx représente la vitesse linéaire du mouvement de translation selon l'axe X, calculée préférentiellement comme étant la dérivée de la distance R, ou mesurée à partir de la vitesse de référence Vx_ref fournie en entrée du variateur Dx en charge de piloter le moteur de rotation Mx (voir flèche en pointillés dans la figure 3),
   • V'x représente l'accélération du mouvement de translation selon l'axe X, calculée comme étant la dérivée de la vitesse V_x,
   • Vy représente la vitesse angulaire du mouvement de rotation du point d'accroche 10,
   • V'y représente l'accélération angulaire du mouvement de rotation, calculée comme étant la dérivée de la vitesse Vy,
   • Kf représente un coefficient de frottement fixe,
   • g représente la pesanteur.

To calculate the swinging angles Θx and Θy and the velocities Θ'x and Θ'y, the estimator module 21 uses a damping pendulum mathematical model, which satisfies the following two equations:

1. a) L * Θ "x = - g * sinΘx - V'x * cosΘx + Vy ² * (R + L * sinΘx) * cosΘx + (Vz - K _f ) * Θ'x
2. b) L * Θ "y = - g * sinΘy - V'y * R * cosΘy + Vy ² * L * sinΘy * cosΘy + (Vz - K _f ) * Θ'y
   in which :
   • Θx represents the first bending angle of the load along the X axis,
   • Θ'x represents the speed of the swinging angle Θx,
   • Θ "x represents the acceleration of the swinging angle Θx,
   • Θy represents the second swing angle of the load along the Y axis,
   • Θ'y represents the speed of the swinging angle Θy,
   • Θ "y represents the acceleration of the swinging angle Θy,
   • L represents the length of the cables,
   • R represents the distance between the point of attachment of the cables and the axis of rotation Z,
   • Vz represents the speed of the lifting movement, calculated as the derivative of the length L,
   • Vx represents the linear velocity of the translation movement along the X axis, preferably calculated as the derivative of the distance R, or measured from the reference speed Vx _ref supplied to the input of the Dx drive in charge of controlling the motor of Mx rotation (see dashed arrow in the figure 3 )
   • V'x represents the acceleration of the translation movement along the X axis, calculated as the derivative of the speed V _x ,
   • Vy represents the angular velocity of the rotation movement of the point of attachment 10,
   • V'y represents the angular acceleration of the rotational movement, calculated as the derivative of the velocity Vy,
   • Kf represents a fixed coefficient of friction,
   • g represents gravity.

• ■ Vx_t = (R_t - R_t-1) / Δt
• ■ V'x_t = (Vx_t - Vx_t-1) / Δt
• ■ Vz_t = (L_t - L_t-1) / Δt
• ■ Θ"x_t = (-g*sinΘx_t - V'x_t*cosΘx_t + Vy_t ²*(R_t + L_t*sinΘx_t)*cosΘx_t + (Vz_t - K_f)*Θ'x_t)/ L_t
• ■ Θ'x_t = Θ'x_t-1 + Θ"x_t-1 * Δt
• ■ ΘX_t = Θx_t-1 + Θ'x_t-1 * Δt

dans lequel Θx_t et Θx_t-1 représentent le premier angle de ballant respectivement à un instant t et à un instant précédent t-1, Θ'x_t et Θ'x_t-1 représentent la vitesse de l'angle de ballant Θx respectivement aux instants t et t-1, Θ"x_t et Θ"x_t-1 représentent l'accélération de l'angle de ballant Θx respectivement aux instants t et t-1, V'x_t représente l'accélération du mouvement de translation à l'instant t, Vx_t et Vx_t-1 représentent la vitesse du mouvement de translation respectivement aux instants t et t-1, Vz_t représente la vitesse de levage à l'instant t, R_t et R_t-1 représentent la distance R respectivement aux instants t et t-1, Vy_t représente la vitesse de rotation à l'instant t, L_t et L_t-1 représentent la longueur des câbles respectivement aux instants t et t-1 et Δt représente l'écart de temps entre l'instant t et l'instant t-1.Equation a) shows that the control device uses the Θ "x acceleration of the angle Θx as the internal variable and that the only input variables supplied to the estimator module 21 are the length of the cables L, the distance R and the angular velocity of rotation Vy.The first skew angle Θx and the velocity Θ'x are calculated using an iterative process over time, that is, the results are recalculated periodically to each moment t, using in particular the results obtained at the moment previous t-1. This iterative process uses the acceleration Θ "x and can be represented at any time t as follows:

• ■ Vx _t = (R _t -R _t-1 ) / Δt
• ■ V'x _t = (Vx _t - Vx _t-1 ) / Δt
• ■ Vz _t = (L _t - L _t-1 ) / Δt
• ■ Θ "x _t = (-g * sinΘx _t - V'x _t * cosΘx _t + Vy _t ² * (R _t + L _t * sinΘx _t ) * cosΘx _t + (Vz _t - K _f ) * Θ'x _t ) / L _t
• ■ Θ'x _t = Θ'x _t-1 + Θ "x _t-1 * Δt
• ■ ΘX _t = Θx _t-1 + Θ'x _t-1 * Δt

where Θx _t and Θx _t-1 represent the first dangling angle respectively at a time t and at a previous instant t-1, Θ'x _t and Θ'x _t-1 represent the speed of the dangling angle Θx respectively at times t and t-1, Θ "x _t and Θ" x _t-1 represent the acceleration of the swinging angle Θx respectively at times t and t-1, V'x _t represents the acceleration of the movement translation time at time t, Vx _t and Vx _t-1 represent the speed of the translational movement respectively at times t and t-1, Vz _t represents the lifting speed at time t, R _t and R _{t- 1} represent the distance R respectively at times t and t-1, Vy _t represents the speed of rotation at time t, L _t and L _t-1 represent the length of the cables respectively at times t and t-1 and Δt represents the time difference between time t and time t-1.

The iterative process starts from the assumption that at startup, the values of Θx, Θ'x and Θ "x are zero, that is to say that at time t = 0, we have: Θx ₀ = Θ'x ₀ = Θ "x ₀ = 0.

• ■ V'y_t (Vy_t - Vy_t-1) / Δt
• ■ Vz_t = (L_t - L_t-1) / Δt
• ■ Θ"y_t = (-g*sinΘy_t - V'y_t*R*cosΘy_t + Vy_t ² *L_t*sinΘy_t*cosΘy_t + (Vz_t - K_f)*Θ'y_t) / L_t
• ■ Θ'y_t = Θ'_yt-1 + Θ"y_t-1 * Δt
• ■ Θy_t = Θy_t-1 + Θ'y_t-1 * Δt

dans lequel Θy_t et Θy_t-1 représentent le second angle de ballant respectivement à un instant t et à un instant précédent t-1, Θ'y_t et Θ'y_t-1 représentent la vitesse de l'angle Θy respectivement aux instants t et t-1, Θ"y_t et Θ"y_t-1 représentent l'accélération de l'angle Θy respectivement aux instants t et t-1, V'y_t représente l'accélération angulaire du mouvement de rotation à l'instant t, Vz_t représente la vitesse de levage à l'instant t, Vy_t et Vy_t-1 représentent la vitesse angulaire de rotation respectivement aux instants t et t-1, L_t et L_t-1 représentent la longueur des câbles respectivement aux instants t et t-1 et Δt représente l'écart de temps entre l'instant t et l'instant t-1.Equally, equation b) shows that the regulator uses the Θ "y acceleration of the angle Θy as the internal variable and that the only input variables supplied to the estimator module 21 are the length of the cables L, the distance R and the rotational angular velocity Vy.The second dangling angle Θy and the velocity Θ'y are calculated using an iterative process over time, that is, the results are recalculated from periodically at each instant t, using in particular the results obtained at the previous instant t-1 This iterative process uses the acceleration Θ "y and can be represented at any time t as follows:

• ■ V'y _t (Vy _t - Vy _t-1 ) / Δt
• ■ Vz _t = (L _t - L _t-1 ) / Δt
• ■ Θ "y _t = (-g * sinΘy _t - V'y _t * R * cosΘy _t + Vy _t ² * L _t * sinΘy _t * cosΘy _t + (Vz _t - K _f ) * Θ'y _t ) / L _t
• ■ Θ'y _t = Θ ' _yt-1 + Θ "y _t-1 * Δt
• ■ Θy _t = Θy _t-1 + Θ'y _t-1 * Δt

where Θy _t and Θy _t-1 represent the second swing angle respectively at a time t and at a previous instant t-1, Θ'y _t and Θ'y _t-1 represent the speed of the angle Θy respectively at instants t and t-1, Θ "y _t and Θ" y _t-1 represent the acceleration of the angle Θy respectively at times t and t-1, V'y _t represents the angular acceleration of the rotational movement at time t, Vz _t represents the lifting speed at time t, Vy _t and Vy _t-1 represent the rotational angular velocity respectively at times t and t-1, L _t and L _t-1 represent the length of the cables respectively at times t and t-1 and Δt represents the time difference between the moment t and the moment t-1.

The iterative process starts from the assumption that at startup, the values of Θy, Θ'y and Θ "are zero, that is to say that at time t = 0, we have: Θy ₀ = Θ'y ₀ = Θ "y ₀ = 0.

Equation a) has a specific term "Vy ² * R * cosΘx" which is always positive when the rotation speed Vy is non-zero. This translates the influence of the centrifugal force which makes that, as soon as a rotation movement is in progress (even with a zero acceleration V'y), a first bending angle Θx is created in the X direction, perpendicular to the tangential axis Y. The objective of the regulation is not to cancel this ballant during the rotational movement but only to reach a position of equilibrium with a non-zero ballad of the load 15 corresponding to an angle non-zero equilibrium during the rotation, then return to a swing angle Θx zero at the end of the rotational movement, when the rotation speed Vy is zero. During the rotational movement, this equilibrium angle therefore corresponds to an offset value, denoted by Θx _eq . When the rotational movement is in progress, we do not try to cancel this offset value Θx _eq , but we try to stabilize the load without oscillation with an inclination corresponding to the offset value Θx _eq . After approximation, the offset value Θx _eq can be determined by the following equation (Θx _eq expressed in radians): $${\mathrm{.theta.x}}_{\mathrm{eq}}=\mathrm{R}*{\mathrm{Vy}}^{\mathrm{2}}/\left(\mathrm{boy\; Wut}-\mathrm{The}*{\mathrm{Vy}}^{\mathrm{2}}\right)$$

This equation shows that the offset value Θx _eq is proportional to the rotation speed Vy and is zero when the rotation speed Vy is zero.

• ■ ΔVx = K_Θx * (Θx - Θx_eq) + K'_Θx * Θ'x
• ■ ΔVy = K_Θy * Θy + K'_Θy * Θ'y

dans lequel K_Θx et K_Θy sont des coefficients de correction appliqués respectivement aux angles de ballant Θx et Θy pour les mouvements de translation et de rotation, K'_Θx et K'_Θy sont des coefficients de correction appliqués respectivement aux vitesses des angles de ballant Θ'x et Θ'y pour les mouvements de translation et de rotation, ΔVx et ΔVy sont les signaux de correction à appliquer respectivement aux consignes de vitesse Vcx et Vcy, et Θx_eq est la valeur d'offset de l'angle Θx durant le mouvement de rotation.The corrector module 22 receives as input the calculated estimates of Θx, Θy, Θ'x, Θ'y from the estimator module 21 and applies to them a correction coefficient K _Θ , respectively K ' _Θ , to provide the correction signals ΔVx and ΔVy, according to the following equations:

• ■ ΔVx = K _Θx * (Θx - Θx _eq ) + K ' _Θx * Θ'x
• ■ ΔVy = K _Θy * Θy + K ' _Θy * Θ'y

in which K _Θx and K _Θy are correction coefficients respectively applied to the swinging angles Θx and Θy for translation and rotation movements, K ' _Θx and K' _Θy are correction coefficients respectively applied to speeds of the swinging angles Θ'x and Θ'y for the translational and rotational movements, ΔVx and ΔVy are the correction signals to be applied respectively to the speed commands Vcx and Vcy, and Θx _eq is the offset value of the angle Θx during the rotational movement.

The first correction signal ΔVx therefore does not depend directly on the first swing angle Θx but on the difference between the first swing angle Θx and the offset value Θx _eq . Thus, when a rotational movement is in progress (speed Vy _ref not zero), the offset value Θx _eq is non-zero and therefore the regulating device 20 delivers a correction signal ΔVx which takes into account the value of offset generated by the centrifugal force on the swinging angle Θx. When the rotational movement is stopped (zero Vyref speed), the offset value Θx _eq automatically becomes zero and the regulator 20 then applies a correction signal ΔVx which is proportional to Θx and Θ'x.

The speed reference Vx _ref applied to the input of the converter Dx driving the translation motor Mx is therefore equal to the speed reference of the translational movement Vcx originating from the control automation system of the crane 5, increased by the first correction signal ΔVx delivered by the regulating device 20, that is to say: Vx _ref = Vcx + ΔVx.

Similarly, the speed reference Vy _ref applied to the input of the drive Dy driving the rotation motor My is equal to the speed reference of the rotational movement Vcy coming from the control automation system of the crane 5, increased by the second signal correction ΔVy delivered by the regulating device 20, that is to say: Vy _ref = Vcy + ΔVy.

According to a first simplified embodiment, the values of the correction coefficients K _Θ , K ' _Θ are fixed. According to a second preferred embodiment, the values of the correction coefficients K _Θ , K ' _Θ are modifiable as a function of the length L of the cables determined by the device 20, so as to optimize the speed corrections to be made according to the height of the pendulum formed by the load 15. In this case, the correction module 22 receives as input information representative of the length L and is therefore capable of storing several values of K _Θ , K ' _Θ along the length L.

In a first situation, it is assumed that the automation system of the crane 5 controls only a displacement in rotation, that is to say that it provides a translation speed setpoint Vcx which is zero. The rotational movement thus generates a first swinging angle Θx along the translation axis X caused by the centrifugal force applied to the load 15, as well as a second swinging angle Θy along the tangential axis Y caused by the acceleration / deceleration of the rotational movement. As indicated above, the first swinging angle can be canceled only by acting on the translational movement.

However, if no displacement in translation is requested by the automation system, it is necessary that the final position of the point of attachment is identical to its initial position, that is to say that the final distance R at the end rotational movement is equal to the initial distance R at the start of movement, regardless of the corrections applied in translation to cancel the first swinging angle Θx due to rotation. This is why the corrector module 22 of the regulating device 20 stores the initial distance R and applies, at the end of the rotational movement, a correction signal ΔVx suitable for bringing the attachment point 10 back to its initial position, so that R final = initial R.

In a second situation, the automation system of the crane 5 also controls a translational movement, that is to say that it also provides a non-zero translation speed reference Vcx. This translational movement also creates a swinging along the X axis caused by the acceleration / deceleration of the translational movement. The first dangling angle Θx then represents the accumulation of the dangling generated by the translation and rotation movements.

Advantageously, the control device does not include any preliminary modeling step, which would require measuring other physical parameters such as a measurement of the swing angle or a measurement of the current flowing in the motor, for the purpose of determining or to refine a particular mathematical model or for the purpose of establishing a transfer function between the speed of the carriage and the dangling angle measured by a sensor for a given cable length.

The control device thus described is intended to be implanted in an automation system of the crane 5, responsible in particular for controlling and monitoring the movements of the load 15. This automation system comprises in particular a speed variator Dx for the movement translation and a variable speed drive Dy for the rotational movement. Due to its simplicity, the control device can be installed directly in the variable speed drives Dx and Dy, for example by means of a specific module of the drive. The automation system may also include a programmable controller which serves in particular to provide the Vcx and Vcy speed instructions. In this case, the control device can also be easily integrated into an application program of the programmable controller.

The regulating device implements a method for regulating the displacement of the load 15 in a rotational movement around the Z axis possibly associated with a translation movement along the X axis. The regulation method comprises a calculation step , carried out by the estimator module 21, which makes it possible to determine a first swinging angle Θx and a speed Θ'x of this swinging angle. The calculation step uses only the length L, the distance R and the rotation speed Vy of the hook point 10 as input variables and uses the acceleration Θ "x as an internal variable. a pendulum model with damping.

The control method also comprises a correction step performed by the correction module 22. The correction step calculates an offset value Θx _eq of the angle Θx which is proportional to the rotation speed Vy and delivers a first signal correction ΔVx of the translation speed which takes into account the offset value Θx _eq . The first correction signal ΔVx is calculated by applying a correction coefficient K _Θx to the difference between the first swinging angle Θx and the offset value Θx _eq and a correction coefficient K ' _Θx at the speed Θ'x.

Claims (22)

1. A control device for controlling the movement of a load (15) suspended by suspension cables (14) from a suspension point (10) of a hoisting machine (5), the suspension point (10) being capable of performing a rotation movement about a vertical rotation axis (Z) and a translation movement along a translation axis (X), the rotation movement generating a first sway angle (Θx) of the load (15) along the translation axis (X), characterized in that the control device (20) comprises calculation means that determine the first sway angle (Θx) and a speed (Θ'x) of the first sway angle (Θx), using as the only input variables information representative of a length (L) of the suspension cables (14), information representative of a distance (R) between the rotation axis (Z) and the suspension point (10) and information representative of a rotation speed (Vy) of the suspension point (10), and using as internal variable an acceleration (Θ"x) of the first sway angle (Θx).
2. The control device as claimed in claim 1, characterized in that the calculation means determine the first sway angle (Θx) and the speed (Θ'x) of the first sway angle (Θx) by means of an iterative process using the acceleration (Θ"x) of the first sway angle (Θx).
3. The control device as claimed in claim 2, characterized in that the calculation means determine the first sway angle (Θx) of the load (15) by also taking into account the translation movement made by the suspension point (10) along the translation axis (X).
4. The control device as claimed in claim 2, characterized in that the control device (20) calculates an offset value (Θx_eq) of the first sway angle (Θx) which is a function of the rotation speed (Vy) of the suspension point (10) and delivers a first correction signal (ΔVx) for the speed of the translation movement of the suspension point (10) which takes into account the offset value (Θx_eq).
5. The control device as claimed in claim 4, characterized in that the first correction signal (ΔVx) is proportional to the difference between the first sway angle (Θx) and the offset value (Θx_eq) and is proportional to the speed (Θ'x) of the first sway angle (Θx).
6. The control device as claimed in claim 5, characterized in that the first correction signal (ΔVx) is added to a speed setpoint (Vcx) in order to supply a speed reference (Vx_ref) for the translation movement of the suspension point (10), the first correction signal (ΔVx) being calculated by applying a correction coefficient (K_Θx, K'_Θx) to the difference between the first sway angle (Θx) and the offset value (Θx_eq) and to the speed (Θ'x) of the first sway angle (Θx).
7. The control device as claimed in claim 6, characterized in that the correction coefficients (K_Θx, K'_Θx) are variable as a function of the length (L) of the suspension cables (14) of the load (15).
8. The control device as claimed in claim 4, characterized in that the calculation means calculate a second sway angle (Θy) of the load (15) along a tangential axis (Y) perpendicular to the translation axis (X) and a speed (Θ'y) of the second sway angle (Θy), using as the only input variables the information representative of the length (L), the information representative of the distance (R) and the information representative of the rotation speed (Vy) and using as internal variable an acceleration (Θ"y) of the second sway angle (Θy).
9. The control device as claimed in claim 8, characterized in that the calculation means (21) determine the second sway angle (Θy) and the speed (Θ'y) of the second sway angle (Θy) by means of an iterative process using the acceleration (Θ"y) of the second sway angle (Θy).
10. The control device as claimed in claim 9, characterized in that the control device (20) supplies a second correction signal (ΔVy) for the rotation speed calculated by applying a correction coefficient (K_Θy, K'_Θy) to the second sway angle (Θy) and to the speed (Θ'y) of the second sway angle.
11. An automation system designed to control the movement of a load (15) suspended by suspension cables (14) from a suspension point (10) of a hoisting machine (5), characterized in that the automation system comprises a control device as claimed in one of the preceding claims.
12. A method for controlling the movement of a load (15) suspended by suspension cables (14) from a suspension point (10) of a hoisting machine (5), the suspension point (10) being capable of performing a rotation movement about a vertical rotation axis (Z) and a translation movement along a translation axis (X), the rotation movement generating a first sway angle (Θx) of the load (15) along the translation axis (X), characterized in that the method comprises a calculation step which determines the first sway angle (Θx) and a speed (Θ'x) of the first sway angle (Θx), using as the only input variables information representative of a length (L) of the suspension cables (14), information representative of a distance (R) between the rotation axis (Z) and the suspension point (10) and information representative of a rotation speed (Vy) of the suspension point (10), and using as internal variable an acceleration (Θ"x) of the first sway angle (Θx).
13. The control method as claimed in claim 12, characterized in that the calculation step determines the first sway angle (Θx) and the speed (Θ'x) of the first sway angle (Θx) by means of an iterative process using the acceleration (Θ"x) of the first sway angle (Θx).
14. The control method as claimed in claim 13, characterized in that the calculation step determines the first sway angle (Θx) of the load (15) by also taking into account the translation movement made by the suspension point (10) along the translation axis (X).
15. The control method as claimed in claim 13, characterized in that the method comprises a correction step which calculates an offset value (Θx_eq) of the first sway angle (Θx) which is proportional to the rotation speed (Vy) of the suspension point (10) and which delivers a first correction signal (ΔVx) for the speed of the translation movement of the suspension point (10) which takes into account the offset value (Θx_eq).
16. The control method as claimed in claim 15, characterized in that the first correction signal (ΔVx) is proportional to the difference between the first sway angle (Θx) and the offset value (Θx_eq) and is proportional to the speed (Θ'x) of the first sway angle (Θx).
17. The control method as claimed in claim 16, characterized in that the first correction signal (ΔVx) is added to a speed setpoint (Vcx) in order to supply a speed reference (Vx_ref) for the translation movement of the suspension point (10), the first correction signal (ΔVx) being calculated by applying a correction coefficient (K_Θx, K'_Θx) to the difference between the first sway angle (Θx) and the offset value (Θx_eq) and to the speed (Θ'x) of the first sway angle (Θx).
18. The control method as claimed in claim 17, characterized in that the correction coefficients (K_Θx, K'_Θx) are variable as a function of the length (L) of the suspension cables (14) of the load (15).
19. The control method as claimed in claim 13, characterized in that the calculation step determines a second sway angle (Θy) of the load (15) along a tangential axis (Y) perpendicular to the translation axis (X) and a speed (Θ'y) of the second sway angle (Θy), using as the only input variables the information representative of the length (L), the information representative of the distance (R) and the information representative of the rotation speed (Vy), and using as internal variable an acceleration (Θ"y) of the second sway angle (Θy).
20. The control method as claimed in claim 19, characterized in that the calculation step determines the second sway angle (Θy) and the speed (Θ'y) of the second sway angle (Θy) by means of an iterative process using the acceleration (Θ"y) of the second sway angle (Θy).
21. The control method as claimed in claim 19, characterized in that the method comprises a correction step which supplies a second correction signal (ΔVy) for the rotation speed calculated by applying a correction coefficient (K_Θy, K'_Θy) to the second sway angle (Θy) and to the speed (Θ'y) of the second sway angle.
22. The control method as claimed in claim 13, characterized in that the calculation step uses a pendulum mathematical model with damping.

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