CRANE WITH CRANE CONTROL
20240367948 · 2024-11-07
Inventors
Cpc classification
B66C23/58
PERFORMING OPERATIONS; TRANSPORTING
B66C13/48
PERFORMING OPERATIONS; TRANSPORTING
International classification
B66C13/48
PERFORMING OPERATIONS; TRANSPORTING
B66C23/42
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A crane with a crane control, wherein the crane control includes rises a coordinate control system with a plurality of nodes defined in the crane, a three-axis coordinate system including x, y and z axes that intersect each other in orthogonal main planes in the space, a node information processing module, a route establishment module and an operation processing module, wherein the node information processing module is configured to collect and store node information in an initial state of the crane, and the route establishment module is configured, based on a control command indicated by a crane operator, to establish an effective operation path for each node to a route in which the operation module is used, in an actual route, for displacing a crane tip included in the crane from a current starting or initial coordinate position in the initial state to a desired target coordinate position in the space.
Claims
1. A crane (1) with crane control (2), which crane control comprises, a coordinate control system with a plurality of nodes (N1, N2, N3, N4) defined in the crane and a three-axis coordinate system including x, y and z axes intersecting each other in orthogonal main planes in the space, a node information processing module (2a), a route establishment module (2b) and an operation processing module (2c), wherein the node information processing module is configured to collect and store node information in an initial state of the crane (1), and the route establishment module is configured, based on a control command indicated by a crane operator, to establish an effective operation path for each node to a route in which the operation module is used, in an actual route, to displace a crane tip (TCP) included in the crane from a current starting or initial coordinate position (SP) in the initial state to a desired target coordinate position (TP) in the space, characterized by the route establishment module (2b) being configured, in a preparatory calculation step, to plan the actual motion of the crane tip (TCP) along a route by dividing the effective operation path of each node (N1, N2, N3, N4) into a series of fictional partial steps (TS:1-TS:n), wherein each node is assigned a predetermined mobility status, wherein a predetermined procedure generates a control strategy assigning the mobility status to the current node, its mobility status being based on an instruction in the operator's indicated control command.
2. A crane according to claim 1, wherein the instruction of the operator's control command is performed in respect of the operator's desired change of position In (dX), Out (+dX), Up (+dY), Down (dY) by displacement of the crane tip (TCP) relative to the main planes of the coordinate system.
3. A crane according to anyone of claims 1-2, wherein each node (N1, N2, N3, N4) is assigned a free mobility status or a locked mobility status during each fictional partial step, and wherein said free mobility status implies that the node is only allowed to be displaced along a single partial stretch (dX, dY) or a combination of a first partial stretch (dX) and a second partial stretch (dY), and wherein each such partial stretch constitutes a linear projection of an operation path for the node towards some of the main plane of the coordinate system, and wherein said locked mobility status implies that the node is fixed against displacement.
4. A crane according to claim 3, wherein the first partial stretch (dX) is situated in a horizontal plane in the space, and the second partial stretch (dY) is situated in a vertical plane in the space, and said partial stretches (dX, dY) intersect each other in a fictional point B that is generated in the preparatory calculation step.
5. A crane according to anyone of claims 1-3, wherein the route establishment module (2b) is configured, in each partial step (TS:1-TS:n), to calculate a first fictional displacement of each node (N1, N2, N3, N4) along a partial stretch (dX) and displacement only in a horizontal plane in the space and subsequently calculate a second fictional displacement of each node along a partial stretch (dY) and displacement only in a vertical plane in the space.
6. A crane according to anyone of claims 1-5, wherein at least one node (N1, N2, N3, N4) in a coordinate control system is fixed against displacement during each fictional partial step (TS:1-TS:n) by the preparatory calculation step.
7. A crane according to anyone of claims 1-6, wherein the procedure is configured to select a control strategy based on at least one of the following instructions indicated in the crane operator's control command at a desired speed of change in the state of the crane tip; motion command in an in/out component (deltaX) in the coordinate system, motion command in an up/down component (deltaY) in the coordinate system, or a combination of said motions in an in/out component (deltaX) and up-down component (deltaY).
8. A crane according to anyone of claims 1-7, wherein the route establishment module (2b) further comprises a dynamic model, which is configured to generate a modified control strategy in respect of a risk detected in the preparatory calculation step of losing a degree of freedom (q1, q2, q3, d) of motion freedom in the crane (1) by establishing an effective operation path for each node to a route for displacing the crane tip (TCP).
9. A crane according to claim 8, wherein the dynamic model controls the risk of losing a degree of freedom (q1, q2, q3, d) of motion in the crane on the basis of at least one of the following parameters; data stored in the crane control (2), comprising predetermined static and dynamic limitations of the crane in respect of loads or accelerations in the crane calculated in said preparatory calculation step, data stored in the crane control (2), comprising predetermined structural geometric state restrictions of the actuators and activators (23, 24, 25, 26) included in the crane with respect to a control strategy generated in said preparatory calculation step, resulting in some of the actuators and activators having to bypass in their end positions for the crane tip (TCP) to reach a desired target coordinate position (TP) in the space.
10. A crane according to anyone of claims 1-9, wherein the route establishment module (2b) is configured to reduce or restrict the speed of change desired by the crane operator of the state of the crane tip (TCP), if any of the actuators and activators (23, 24, 25, 26) included in the crane (1) travel towards an end position, wherein the speed is successively reduced, such that the function of the current actuator and activator stops softly just before it reaches the end position.
11. A crane according to anyone of claims 7-10, the dynamic model comprising a motion-restriction module with a motion-restricting procedure that can limit the scope of motion of the joints by means of input to the crane tip control algorithm, which input can at least comprise the following restrictions; restriction of the crane tip (TCP) velocity over a cargo compartment, if a crane-carrying vehicle is equipped with such a superstructure component, preventing the crane (1) from being run if a loading gate or a cabin roof, if a crane-carrying vehicle is equipped with such superstructure component.
12. A crane according to anyone of claims 7-11, wherein the dynamic model comprises a motion-restricting procedure that can restrict the motion speed of the nodes (N1, N2, N3, N4) within one or a plurality of predetermined zones (Z:1-Z:n) in the three-dimensional coordinate system in the space, and which data is are used as input to the route establishment module (2b).
13. A crane according to anyone of claims 1-12, comprising crane control 2 configured, such that, via an operator interface, it is switched into different operating modes of which a first operating mode comprises operating mode for coordinate control, whereby the crane 1 is controlled and monitored on the basis of the desired motions of the crane tip TCP, a second operating mode for conventional manual control of the crane (1) through separate control and monitoring of each actuator and activator (23, 24, 25, 26) of the crane.
14. A crane according to anyone of claims 1-13, comprising a crane base (22), a pillar (10), which is rotatably mounted on the crane base (22) and pivotable relative to the crane base about a vertical rotary shaft (10a) defining a first degree of freedom (q1) of the crane, an operating device (23) for rotating the pillar (10) relative to the crane base (22), a crane arm system (10) comprising a first and a second crane arm (11, 12), which are articulately connected with each other and associated articulators and activators comprising hydraulic cylinders (23, 24, 25, 26) for lifting and lowering the crane arms (11, 12), whereby the first crane arm (11) of the crane arm system via a pivot pin (32) is articulately connected with the pillar (10) for pivoting about a horizontal joint shaft defining a second degree of freedom (q2) of the crane, and the second crane arm (12) of the crane arm system via a pivot pin (33) is articulately connected with the first crane arm (11) for pivoting about a horizontal joint shaft, and which defines a third degree of freedom (q3) of the crane, a sliding boom (13), which via an actuator and activator (26) comprising a hydraulic cylinder, is slidably mounted in the second crane arm (12) and slidable over a structural predetermined sliding area and has a degree of freedom (q4) due to its slidable mounting.
15. A forest machine, such as a forwarder, harvester or similar crane-equipped vehicle intended for tree handling, characterized in that it comprises a crane (1) with crane control (2) according to anyone of claims 1-14.
Description
DESCRIPTION OF FIGURES
[0025] In the following, the invention is described in detail with reference to the accompanying drawings, in which;
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
DESCRIPTION OF EMBODIMENTS
[0033]
[0034]
[0035] In the following, it should be understood that the crane 1 with associated crane control 2 according to the invention could comprise any known type of crane with an arm system for handling of goods, also a crane of the type intended to be used for load handling at a truck such as a timber truck or similar cargo vehicle.
[0036] According to the invention, the crane 1 with computer-based crane control 2 can be configured to be switched to various operating modes of which; a first operating mode could comprise operating mode for coordinate control, whereby the arm system 1 is controlled and monitored on the basis of the desired motions from the crane tip TCP. The crane control 2 can also be configured, such that the crane can be operated in another operating mode for conventional manual control of the crane and thus via separate control and monitoring of each separate actuator of the crane. The crane control 2 can suitably be configured, such that an operator, via a selector switch or similar operator interface included in the crane control 2, can easily switch between said respective operating modes for the crane. In an embodiment, it is also imaginable that the operating modes could be switched automatically depending on the crane configuration, selected functions in the control system or otherwise the status of the machine.
[0037] With reference to
[0038]
[0039] Also with reference to
[0040] As shown in
[0041] By means of measurement data from the measuring elements 31, 32, 33, 34, the crane control 2 can continuously determine the mutual geometric state between the crane pillar 10, the first crane arm 11, the second crane arm 12 and the sliding boom 13 and on the basis of these calculate the crane tip TCP state in the three-dimensional space in a coordinate system denoted X, Y, Z in
[0042] However, it should be understood that the description above substantially constitutes prior art known for a long time for crane controls using coordinate and crane tip control of cranes.
[0043] As mentioned initially, it is desirable to obtain a crane 1 with a crane control 2 that is more suitable to use in the operator-controlled type of cranes included in for example forest machines or similar crane-carrying work vehicles.
[0044] The core of the invention is based on the insight that calculation of the actual displacement of the crane tip TCP from a current starting position SP to a target position GP in a simple manner can be determined by, in a preparatory fictional calculation step, partly giving freedom to and partly locking a specific number of degrees of freedom q1, q2, q3, d in the crane arm system in order to form a fictional arm system, wherein each degree of freedom, i.e. in practice each pivot point (node N1, N2, N3, N4) or slidably moveable part) included in the arm system 10, in a number of (n) fictional successive translative displacement steps TS:1-TS:n, motions are only allowed in two linear directions in x and y directions that intersect each other in a fictional point B that is generated in the preparatory calculation step. The fictional point B is no real point in the coordinate system, but is merely created to simplify the mathematics in the calculation step. Correspondingly, the other displacement steps TS:1-TS:n of the coordinate control in each degree of freedom q1, q2, q3, d are divided into a number of successive fictional speed components in at least x and y directions. To facilitate the understanding, the motion of the crane arm system above is merely described on the basis of a motion in a vertical plane in the x and y directions in the space, i.e. in motion in/out and up/down in the plane. By including the swing of the crane arm system about the z axis and the degree of freedom q1, the crane arm system can reach each point in the space with application based on a quadric coordinate system. By applying a cylindrical coordinate system, the swing function takes place separately, and the algorithm should therefore only process the degrees of freedom q2, q3, d and speed components in x and y directions to reach, in combination with the separate swing function, each desired target point (node) in the space.
[0045] Generating a control strategy in a preparatory step in this manner based on an instruction from the operator's control command, partly assigning motion freedom, partly locking nodes (pivot points) in the arm system during the fictional translative displacement steps, the calculations in the crane control can be substantially simplified, and the need for complicated Jacobian matrices with approximate weighting matrices used in prior art for cranes with crane controls can be avoided. The instruction of the operator's control command is obtained in respect of operator's desired change of position In (dX), Out (+dX), Up (+dY), Down (dY) for said displacement of the crane tip (TCP) relative to the main plane of the coordinate system in the space, from a starting position SP to a target position GP of the crane tip TCP.
[0046] With reference to
Example 1
[0047] Also with reference to
[0048] Thus, an algorithm included in a node information processing module 2a divides the requested displacement into a first velocity vector Vx for the first degree of freedom d (sliding boom and crane tip) for performing a fictional motion in a horizontal in/out component dX and a second motion vector Vy for the crane tip and execution of a fictional motion in a vertical up-down component dY. The procedure 5 comprised by the node information processing module 2a (see
[0049] More specifically, a free mobility status and a locked mobility status, respectively, is assigned to the node N4 at the crane tip, and said free mobility status implies that the node is only allowed to be displaced along a single partial stretch +dX, +dY or a combination of a first partial stretch dX and a second partial stretch dY, wherein such partial stretch constitutes a linear projection of an operation path for the node towards some of the main plane of the coordinate system, and said locked mobility status implies that the node is fixed against displacement. The procedure for the crane motion prioritization 5 is applied on the displacement in each direction and thereby results in an equation system for each n displacement step S:1-S: n with two unknown quantities and two equations, which is uniquely solvable mathematically. This algorithm is applied for deltaX/deltaY separately, which is obtained by applying the algorithm in two steps: First, a theoretical crane position is calculated with only displacement of the first degree of freedom d in X direction to a fictional position B, and subsequently the final crane position is calculated on the basis of the theoretical position and only displacement in Y direction from the fictional position B to the actual position C. As appears from
[0050] Thus, it should be understood that according to the invention, the crane motion in a pivot point as requested by the crane operator is divided into two discrete steps; In/Out (delta X step) and Up/Down (delta Y step). Due to this division, it is possibly by means of the predetermined rules controlled by the crane motion prioritization module 2d included in the crane control 2, to control which degrees of freedom q1, q2, q3, d (pivot and translation points) that are to move during the two discrete steps when the crane tip TCP (node N4) moves Out (delta +dX) to the fictional position B and in conclusion up (delta +dY) to finally reach the actual target position C. Furthermore, it should be understood that as the different nodes are only assigned locked mobility status in the fictional partial steps, the final calculation result implies that all defined nodes are usually also assigned a motion.
[0051] The crane tip motion TCP planned in the calculation step in the node information processing module 2a is further addressed to the route establishment module 2b, which establishes an effective operation path for each node N1, N2, N3, N4 for a route that is executed by the operation processing module 2c, so that the crane tip TCP moves according to the operator's control command.
Example 2
[0052] For the operator to avoid the inconvenience that the crane 1 suddenly stops due to inherent geometric or mechanical restrictions in the crane and that the crane tip TCP therefore does not reach the target point GP desired by the operator, the present crane with crane control 2 is provided with a dynamic model, which is configured to generate a modified control strategy with regard to a risk detected in the preparatory step of losing a degree of freedom q1, q2, q3, d of motion freedom in the crane by establishing a route for each node with a view to displacing the crane tip TCP for each effective operation path. In addition to geometric limitations in the crane 1, problems with lost degrees of freedom can appear through limitations of the state in the actuators and activators 23, 24, 25, 26 of the crane. The dynamic model controls and monitors the risk of losing a degree of freedom q1, q2, q3, d of motion in the crane 1 on the basis of at least one of the following parameters; data stored in the crane control 2 comprising predetermined static and dynamic limitations of the crane relative to loads or accelerations of the crane calculated in said preparatory calculation step, data stored in the crane control 2 comprising predetermined structural geometric limitations of state of the crane with associated arm parts 10, 11, 12, 13 as such or the actuators and activators 23, 24, 25, 26 included in the crane with respect to a control strategy generated in said preparatory calculation step, resulting in some of the actuators and activators having to pass their end position for the crane tip TCP to reach a desired target coordinate position TP in the space.
Example 3
[0053] The crane control 2 comprises software that continuously calculates occurring angle speeds in the pivot points of the crane 1 based on signals from the measuring elements 31, 32, 33, 34 that are provided for the pivotable assemblies 10a, 11a, 12a, 13a between the different crane parts. In a similar manner, the stroke length and motion speeds of the actuators and activators (hydraulic cylinders) are measured via linear measure sensors (similar to that of the measurement sensor 34 in the sliding boom 13). The crane control 2 is configured to reduce or limit the possible range of motion for each node. The crane tip TCP can usually move at a maximum speed until a subsequent predetermined node takes over the motion. If two or more nodes in the crane control reaches their limitation, the motion speed of the crane tip TCP can be affected, whereby the crane control 2 priority is to allow the crane tip to follow the indicated motion line along the route. If the displacement of the crane tip TCP desired by the operator implies that any of the actuators and activators 23, 24, 25, 26 used for operating the crane parts in the crane 1 approach an end position, the software included in the crane control ensures that the speed of the current crane part is successively reduced, so that the function stops softly just before it reaches the end position.
Example 4
[0054] As shown in