Automatic following system and method for lifting appliance of crane

Abstract

The invention provides an automatic following system and method for a crane lifting appliance, and the system comprises a frequency converter and a trolley motor, and also comprises a lifting appliance shaking collection device for collecting real-time shaking data of the lifting appliance; the lifting appliance shake acquisition device transmits acquired real-time shake data of the lifting appliance to the frequency converter; the frequency converter controls the speed and the direction of the trolley motor according to the real-time shaking data of the lifting appliance; the lifting appliance shake collecting device comprises a light reflecting device arranged on the lifting appliance upper frame and a laser scanner arranged on the trolley, and the laser scanner scans the light reflecting device under the control of the controller to obtain shake data of the lifting appliance. The method realizes automatic following of the lifting appliance of the crane. According to the automatic following system and method for the crane lifting appliance, the problems that the shaking amount of the lifting appliance is large due to improper manual operation, one-time accurate alignment is difficult to achieve, and the production operation efficiency is affected can be well solved.

Description

Technical Field

[0001] This invention relates to an automatic following system and method for crane lifting devices. Background Technology

[0002] As a key piece of equipment in container terminals, the operational efficiency of container cranes is directly impacted by their controllability. Traditional container crane operations involve an operator in the cab maneuvering each step. During operation, the spreader needs to follow the trolley's movement in real-time to align with the container to be lifted. The operator controls the trolley's direction and speed by manipulating the trolley levers, thereby controlling the spreader's following distance and achieving precise alignment. However, in actual operation, it is difficult for the operator to precisely control the speed using the trolley levers, leading to swaying of the spreader and making it difficult to achieve accurate alignment with the container on the first attempt, thus severely impacting operational efficiency.

[0003] Currently, to overcome the difficulty for drivers to accurately control the speed when manipulating the trolley handle during actual operations, which leads to the spreader swaying back and forth, the industry has added automatic follow-up systems to cranes, forming an automatic following spreader. For example, utility model patent publication number CN 208732425 U discloses an automatic following spreader for a crane. This spreader includes a spreader body and a control device. An electronic compass is installed on the spreader body; the electronic compass is used to measure the angle between the spreader body and a specified direction; the control device controls the rotation of the spreader body based on the signal fed back from the electronic compass. In this type of crane, the control device sets the initial angle between the automatic following spreader and the specified direction according to the environment in which the crane is used. When the crane operates with this automatic following spreader, the spreader always maintains a fixed angle with the specified direction, thus eliminating the need for manual adjustment during container loading and unloading, improving efficiency and ensuring accuracy. However, this system does not solve the problem of drivers struggling to control the speed when manipulating the trolley handle during actual operations, leading to the spreader swaying back and forth. Summary of the Invention

[0004] This invention addresses the shortcomings of current automatic following spreaders on cranes, which are prone to back-and-forth swaying. It provides an automatic following system and method for crane spreaders, achieving closed-loop feedback for spreader position control, and ultimately realizing precise alignment and real-time position tracking between the spreader and the target position.

[0005] The technical solution adopted by this invention to achieve its technical objective is as follows: an automatic following system for crane spreaders, including a frequency converter and a trolley motor, and a spreader sway acquisition device for collecting real-time sway data of the spreader; the spreader sway acquisition device transmits the collected real-time sway data of the spreader to the frequency converter; the frequency converter controls the speed and direction of the trolley motor according to the real-time sway data of the spreader; the spreader sway acquisition device includes a reflector installed on the upper frame of the spreader and a laser scanner installed on the trolley, the laser scanner scanning the reflector under the control of the controller to obtain the sway data of the spreader.

[0006] Furthermore, in the aforementioned automatic crane lifting device tracking system: the reflective device is a white reflector installed on the lifting device frame.

[0007] Furthermore, in the aforementioned automatic crane lifting device tracking system: the white reflector is a square white board with one side aligned with the direction of movement of the main trolley and the other side aligned with the direction of movement of the auxiliary trolley; when the laser scanner scans the white reflector, the direction of movement of the main trolley is taken as the X-axis of the coordinate system and the direction of movement of the auxiliary trolley is taken as the Y-axis of the coordinate system, and the origin of the coordinate system is set at the reference point of the crane track.

[0008] Furthermore, in the aforementioned automatic crane lifting device tracking system: the laser scanner is an integrated laser scanner, including a laser scanning head with a laser transceiver, a rotation mechanism that drives the laser scanning head, and a rotation mechanism controller.

[0009] Furthermore, in the aforementioned crane spreader automatic following system: the spreader sway acquisition device uses a first photoelectric conversion module mounted on the trolley frame and a second photoelectric conversion module mounted in the motor room to transmit the real-time sway data of the spreader collected by the laser scanner to the main control PLC. After receiving the real-time sway data of the spreader and completing the calculation, the main control PLC sends the given control speed and direction data to the frequency converter.

[0010] The present invention also provides a method for automatic following of a crane spreader, which includes the following steps: Step 1: The laser scanner collects and reads the reflector feature data; Step 2: The main control PLC receives the position information of the lifting device; Step 3: The main control PLC calculates and sends the running speed data; Step 4: The frequency converter receives the operating speed data and outputs the operating speed. Step 5: The trolley motor runs at a speed that allows the lifting device to follow.

[0011] Furthermore, in the aforementioned automatic following method for crane spreaders: in step 1, the characteristic data of the reflector includes position data. When a laser scanner acquires and reads the position data of a reflector, it includes: Step 101: The controller receives the X-axis and Y-axis position data of the reflector; Step 102: The controller controls the laser scanner to rotate; turn direction step 101.

[0012] Furthermore, in the above-mentioned automatic following method for crane lifting devices: in step 101, the X-axis and Y-axis position data of the reflector are as follows: the X-axis corresponds to the moving direction of the crane trolley, the Y-axis corresponds to the moving direction of the trolley, and the origin of the coordinate system is set at the reference point of the crane track.

[0013] Furthermore, in the above-mentioned automatic following method for crane lifting devices: when the laser scanner scans the reflector, it collects the distance and angle from the laser scanner head, including the horizontal scanning angle and the vertical pitch angle.

[0014] The automatic crane lifting device tracking system and method of the present invention can effectively solve the problems of large lifting device sway caused by improper manual operation, making it difficult to achieve accurate alignment in one go and affecting production efficiency.

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0016] Appendix Figure 1 This is a schematic diagram of the automatic following system for crane lifting devices according to Embodiment 1 of the present invention; Appendix Figure 2 This is a schematic diagram of a laser scanner scanning a white reflector according to Embodiment 1 of the present invention; Appendix Figure 3 This is a flowchart illustrating the configuration of each module in the automatic crane lifting device following system of Embodiment 1 of the present invention. Appendix Figure 4 This is a flowchart of the automatic following steps of the crane lifting device in Embodiment 1 of the present invention. Detailed Implementation

[0017] This embodiment is an automatic following system for crane spreaders, such as... Figure 1 As shown: This includes a frequency converter and a trolley motor, as well as a sway data acquisition device for collecting real-time sway data of the spreader; the sway data acquisition device transmits the collected real-time sway data of the spreader to the frequency converter; the frequency converter controls the speed and direction of the trolley motor based on the real-time sway data; the sway data acquisition device... Figure 2 As shown, the device includes a reflector mounted on the upper frame of the lifting device and a laser scanner 100 mounted on the trolley. Under the control of the controller, the laser scanner 100 generates a laser beam 101 to scan the reflector (white reflector 200) to obtain the sway data of the lifting device.

[0018] In this embodiment, based on the existing equipment, a 600mm*600mm white reflector 200 is added to the hoisting device. Figure 2 As shown, the trolley frame is augmented with an integrated laser scanner 100 and a rotating mechanism, a laser scanner 100 and rotating mechanism controller, and a photoelectric conversion module that communicates with the main control PLC in the electrical room. (See attached diagram.) Figure 1 and Figure 2 As shown.

[0019] In this embodiment: the X-axis corresponds to the moving direction of the crane trolley, that is, the lateral translation direction along the track; The Y-axis corresponds to the direction of movement of the trolley, that is, the longitudinal translation direction perpendicular to the track of the main vehicle; The origin of the coordinate system is set at the reference point of the crane track (such as the starting position), and the X-axis and Y-axis form a two-dimensional positioning system in the horizontal plane.

[0020] A white reflector 200 is mounted on the lifting device, serving as the target reflector for the laser scanner. The laser scanner emits laser pulses, and the distance to the white reflector is calculated by measuring the round-trip time of the light. Combined with the scanner's installation position, the real-time XY coordinates in the horizontal coordinate system are calculated. This data is used to accurately identify the spatial attitude of the crane lifting device and trolley, providing basic data input for the anti-sway control algorithm.

[0021] The laser scanner emits laser pulses and measures their round-trip time. The distance to the reflector is calculated using the formula S=c·Δt / 2 (where c is the speed of light and Δt is the time difference).

[0022] The rotation of the X and Y axes is achieved through a dual-axis drive system with a rotating mechanism. The X-axis (lateral rotation) corresponds to the movement direction of the crane trolley and is achieved by the horizontal rotation mechanism. The Y-axis (vertical rotation) corresponds to the movement direction of the trolley and is achieved by the vertical rotation mechanism. The dual-axis drive system is driven by a first stepper motor to rotate around its own axis (Y-axis), while the rotating arm is driven by a second stepper motor to rotate around the horizontal axis (X-axis), forming an orthogonal two-dimensional scanning plane.

[0023] In this embodiment, the laser scanner uses polar coordinates, with the laser emission and reception points as polar coordinate centers. The following data is measured: Distance information The time difference between the emission of the laser pulse and its reflection back to the scanner is measured, and the absolute distance between the reflector and the scanner is calculated by combining the speed of light.

[0024] Angle information Horizontal scanning angle (θ): The rotation angle of the laser beam in the horizontal plane, with the center of the scanner rotation as the origin, covering a range of 0° to 360°.

[0025] Vertical pitch angle (α): The difference in vertical angle between the channels in the laser scanner, used to construct the point cloud height layer information.

[0026] The laser scanner collects real-time data on the reflector's XY coordinates, swing angle, and trolley speed. By comparing the target position with the actual position, ΔX and ΔY are obtained, and the control error is calculated based on the swing angle. An algorithm generates control commands to adjust the trolley motor's acceleration and direction of motion to reduce swaying.

[0027] The process of converting the X-axis and Y-axis position data of the reflector into the position information of the spreader involves mapping the local coordinates of the reflector to the global coordinate system of the crane through mathematical transformation, and calculating the real-time position of the spreader by combining the mechanical structure parameters.

[0028] Coordinate system transformation 1) Polar coordinate to Cartesian coordinate transformation The reflector data acquired by the laser scanner is in polar coordinates (distance ρ, horizontal angle θ, vertical angle α). The following formula converts it to Cartesian coordinates (XL, YL, ZL) in the scanner's local coordinate system: XL=ρ·cosα·cosθ YL=ρ·cosα·sinθ ZL=ρ·sinα Horizontal angle θ: measured in real time by the encoder of the scanner's rotating mechanism.

[0029] Vertical angle α: Fixed channel parameter of the multi-line laser scanner.

[0030] 2) Transformation from the scanner coordinate system to the crane's global coordinate system Transformation matrices achieve coordinate mapping:

[0031] The rotation matrix R is determined by the scanner mounting angles (Euler angles ϕ, θ, ψ).

[0032] Translation vector t: The coordinates of the scanner's installation position in the crane's global coordinate system. ).

[0033] Extraction and modeling of reflector geometric features 1) Point cloud clustering and plane fitting The RANSAC algorithm filters reflector regions from multi-channel point clouds, extracts candidate points through light intensity thresholds, and then fits the plane equation ax+by+cz+d=0.

[0034] The center point is used to calculate the geometric center of a planar point cloud. As the reference point for the reflector, the calculation formula is:

[0035] 2) Reflector attitude calculation The normal vector (a,b,c) extracted from the plane equation reflects the tilt state of the reflector and is used to correct the attitude deviation of the lifting device.

[0036] Angular deviation calculation: the angle between the normal vector and the direction of gravity (Z-axis). If β > 5°, anti-shake control will be triggered.

[0037] Calculation and control of spreader position 1) Mapping of mechanical structure parameters Definition of the lifting device coordinate system: with the center point of the lifting device as the origin, the X-axis is along the direction of trolley movement, the Y-axis is along the direction of main trolley movement, and the Z-axis is the length of the lifting rope.

[0038] Coordinate transformation formula: Position of the reflector in the rigging coordinate system ( The relationship between ) and global coordinates is in: X (small car) Y (large car): The current positions of the small car and the large car.

[0039] L: Length of the suspension rope.

[0040] θ_suspension rope: the angle of the suspension rope.

[0041] 2) Dynamic position prediction and control The PID control algorithm adjusts the movement of the trolley and the main trolley based on the deviations ΔX and ΔY between the predicted and target positions. The relationship is as follows: The parameters are: Kp=0.8, Ki=0.1, Kd=0.05.

[0042] 3) Dynamic error compensation Motion blur compensation is necessary because displacement during the scanning cycle of a crane's high-speed movement can cause coordinate deviations in the reflector. a) Real-time acquisition of the scanner's velocity v and angular velocity ω.

[0043] b) Calculate the pose increments ΔX=vx·T, ΔY=vy·T, and Δθ=ω·T within the scanning period T.

[0044] c) Perform reverse compensation on the coordinates of each sampling point: the reflection compensation formula is as follows:

[0045] After adopting the above technical solution, the sway of the spreader can be collected and read in real time. At the same time, the real-time sway data of the spreader is transmitted to the main control PLC through the controller. After the PLC receives the information and completes the calculation, it sends the given control speed and direction data to the trolley frequency converter, thereby controlling the direction and speed of the trolley motor. This avoids the spreader swaying caused by the trolley's sudden speed changes, and enables the spreader to follow the trolley for precise positioning, thereby improving the production efficiency of the equipment.

[0046] This embodiment designs an automatic follow-up method for the spreader, which can effectively solve the problems of large spreader sway caused by improper manual operation, making it difficult to achieve accurate alignment in one go and affecting production efficiency.

[0047] The automatic spreader tracking system is used to detect the deviation position and actual torsion angle of the spreader in the trolley and carriage directions. That is, it measures the actual deviation and torsion of the spreader in the X-axis and Y-axis directions to realize closed-loop feedback for spreader position control, and ultimately achieve the purpose of precise alignment and real-time position tracking between the spreader and the target position, such as containers and trucks.

[0048] like Figure 4 The crane spreader automatic following method shown in this embodiment includes the following steps: Step 1: The laser scanner collects and reads the reflector feature data; The aforementioned reflector's characteristic data includes position data, which the laser scanner acquires and reads when it reads the reflector's position data, including: Step 101: The controller receives the X-axis and Y-axis position data of the reflector; Step 102: The controller controls the laser scanner to rotate; turn direction step 101.

[0049] Step 2: The main control PLC receives the position information of the lifting device; Step 3: The main control PLC calculates and sends the running speed data; Step 4: The frequency converter receives the operating speed data and outputs the operating speed. Step 5: The trolley motor runs at a speed that allows the lifting device to follow.

[0050] When using the automatic lifting device following system in this embodiment, first follow the steps as follows: Figure 3 The process shown involves setting basic parameters for each module.

[0051] In this embodiment, the anti-shake control algorithm is implemented. 1) Oscillation State Estimation Kalman filtering, fusing data from the laser scanner, encoder, and main control PLC, predicts the position (Xpred, Ypred) and velocity (vx, vy) of the lifting device at the next moment: Xpred=Xkalman+vx·Δt Ypred=Ykalman+vy·Δt (Filtering accuracy: position error < ±5mm, speed error < ±0.1mm / s) 2) Control Strategy PID control is used for basic speed regulation, and the parameters are dynamically adjusted using a particle swarm optimization algorithm.

[0052] In the above formula, the parameters are: Kp=0.8, Ki=0.1, Kd=0.05.

[0053] Input shaping technology injects specific pulses during acceleration and deceleration phases to counteract oscillation energy. The formula is as follows:

[0054] In the above formula, the pulse width T = 0.5s, and the acceleration... .

[0055] In this embodiment, the frequency converter receives the operating speed data and outputs the operating speed as follows: Speed ​​command generation and output Instruction calculation and amplitude limiting Target speed calculation: Based on the speed increments Δvx and Δvy output by the control algorithm, and combined with the current speeds vx_curr and vy_curr of the large and small vehicles, the target speed is generated.

[0056] Safety limits: Set upper limits for speed (vmax=2m / s) and acceleration (amax=0.5m / s2) to prevent mechanical impact.

[0057] Signal output method Communication protocol control: Speed ​​commands are sent via the PROFINET protocol.

[0058] The instruction format is: instruction header + speed value (16 bits) + check bit.

Claims

1. An automatic following system for crane spreaders, comprising a frequency converter and a trolley motor, characterized in that: It also includes a spreader sway acquisition device for collecting real-time spreader sway data; the spreader sway acquisition device transmits the collected real-time spreader sway data to the frequency converter; the frequency converter controls the speed and direction of the trolley motor according to the real-time spreader sway data; the spreader sway acquisition device includes a reflector mounted on the spreader frame and a laser scanner mounted on the trolley, the laser scanner scanning the reflector under the control of the controller to obtain the spreader sway data.

2. The automatic crane lifting device following system according to claim 1, characterized in that: The reflective device is a white reflector installed on the frame of the hoist.

3. The automatic crane lifting device following system according to claim 2, characterized in that: The white reflector is a square white board with one side aligned with the direction of movement of the main trolley and the other side aligned with the direction of movement of the auxiliary trolley. When the laser scanner scans the white reflector, the direction of movement of the main trolley is taken as the X-axis of the coordinate system and the direction of movement of the auxiliary trolley is taken as the Y-axis of the coordinate system. The origin of the coordinate system is set at the reference point of the crane track.

4. The automatic crane lifting device following system according to claim 3, characterized in that: The laser scanner is an integrated laser scanner, including a laser scanning head with a laser transceiver, a rotation mechanism that drives the laser scanning head, and a rotation mechanism controller.

5. The automatic crane lifting device following system according to claim 4, characterized in that: The aforementioned lifting device uses a first photoelectric conversion module mounted on the trolley frame and a second photoelectric conversion module mounted in the motor room to transmit the real-time lifting data collected by the laser scanner to the main control PLC. After receiving the real-time lifting data and performing calculations, the main control PLC sends the given control speed and direction data to the frequency converter.

6. A method for automatic following of a crane spreader, characterized in that: Includes the following steps: Step 1: The laser scanner collects and reads the reflector feature data; Step 2: The main control PLC receives the position information of the lifting device; Step 3: The main control PLC calculates and sends the running speed data; Step 4: The frequency converter receives the operating speed data and outputs the operating speed. Step 5: The trolley motor runs at a speed that allows the lifting device to follow.

7. The automatic following method for crane lifting devices according to claim 6, characterized in that: In step 1, the characteristic data of the reflector includes position data. When a laser scanner acquires and reads the position data of a reflector, it includes: Step 101: The controller receives the X-axis and Y-axis position data of the reflector; Step 102: The controller controls the laser scanner to rotate; turn direction step 101.

8. The automatic following method for crane lifting devices according to claim 7, characterized in that: In step 101, the X-axis and Y-axis position data of the reflector are as follows: the X-axis corresponds to the moving direction of the crane trolley, the Y-axis corresponds to the moving direction of the trolley, and the origin of the coordinate system is set at the reference point of the crane track.

9. The automatic following method for crane lifting devices according to claim 7, characterized in that: When a laser scanner scans a reflector, it collects the distance and angle from the laser scanner head, including the horizontal scanning angle and the vertical pitch angle.

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