Stepless speed regulation control system and method for tower crane

Abstract

The tower crane stepless speed regulation control system comprises a programmable controller, the programmable controller is connected with a linkage table, a frequency converter and a position sensor, the frequency converter is connected with a motor, the motor is provided with a speed measurement encoder, and the speed measurement encoder is connected with the frequency converter. According to the stepless speed regulation control system and method for the tower crane, stepless smooth speed regulation of the tower crane is achieved through communication among the CAN type linkage table, the PLC and the frequency converter, any frequency between 0 and the maximum allowable output frequency is output through the operating rod, and more accurate control is achieved; and meanwhile, when the tower crane runs under a special working condition, the output frequency of the linkage table is reduced in an equal proportion manner through the PLC, so that stepless speed regulation is realized under the condition that the speed of the tower crane is limited, and omnibearing stepless speed regulation is realized.

Description

Technical Field

[0001] The invention relates to the technical field of engineering machinery, and in particular to a tower crane stepless speed regulation control system and method. Background Art

[0002] Tower cranes are a common lifting equipment in construction sites, mainly used for vertical or horizontal transportation of heavy objects. With the development of the construction industry, the working efficiency and working range of tower cranes are becoming more and more demanding, so higher requirements are also put forward for the speed regulation performance of tower cranes. At present, there are mainly the following speed regulation methods for tower cranes: 1. Cascade speed regulation: This debugging method is to adjust the speed by adding electromotive force in series in the rotor circuit of the motor to change the slip of the motor, but this speed regulation system is relatively complex and has high maintenance costs. 2. Stator speed regulation: This method is mainly used for asynchronous motors. The speed of the motor is changed by changing the number of pole pairs of the stator winding or the wiring method of the stator winding. However, the speed adjustment range is limited, and the tower crane vibrates significantly during the speed change process. 3. Electromagnetic speed regulation: Electromagnetic speed regulation uses the connection between the electromagnetic clutch and the motor rotor to change the transmission torque and speed by changing the excitation current of the electromagnetic clutch, but this method has a slow speed regulation response and low accuracy. 4. Hydraulic coupling speed regulation: The hydraulic coupling speed regulation changes the output speed by changing the flow rate of the working fluid in the coupling. This speed regulation method has a simple structure, but low efficiency and low precision. 5. Wound rotor asynchronous motor speed regulation: This method adjusts the speed by changing the rotor circuit resistance of the wound rotor motor, but the speed regulation range is limited and it is more energy-consuming, so it is less used now. 6. AC variable frequency speed regulation: This is the most advanced speed regulation method at present. By controlling the speed of the AC motor through the frequency converter, smooth speed regulation and precise positioning can be achieved. Variable frequency speed regulation has good starting characteristics and low noise operation, and can greatly save energy. At present, mainstream tower cranes are developing in the direction of variable frequency tower cranes, but most of them adopt gear control mode, set the gear frequency, and reduce the impact of the motor of the tower crane during the gear shift through the frequency converter, so as to realize the function of smooth start and precise stop of the tower crane, but the gear change is still graded, and true stepless speed regulation is not achieved. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a tower crane stepless speed regulation control system and method with high accuracy and good effect.

[0004] The present invention is implemented by the following technical scheme: a tower crane stepless speed regulation control system, including a programmable controller, the programmable controller is connected to a linkage table, a frequency converter and a position sensor, the frequency converter is connected to a motor, the motor is provided with a speed encoder, and the speed encoder is connected to the frequency converter.

[0005] It is further described that: the model of the programmable controller is XG-qIMCA 3256GS.

[0006] The linkage platform is a CAN type linkage platform, and the linkage platform is connected to a programmable controller via a CAN line.

[0007] The linkage platform comprises a control panel, and the control panel is connected with a variable amplitude potentiometer and a rotary potentiometer.

[0008] The method of using the tower crane stepless speed control system includes the normal operation condition and the limit condition of the tower crane. When the tower crane is operating normally, the programmable controller sets the maximum operating frequency of the motor output by the linkage table to 100% frequency. At this time, the tower crane driver can achieve stepless speed regulation of the motor from 0% frequency to 100% frequency within the full deflection range of the linkage table operating lever; When the tower crane triggers the deceleration limit, the programmable controller will proportionally reduce the output frequency of the linkage table; When the tower crane triggers the upper stop limit, the programmable controller sends a command to the inverter, and the inverter controls the motor to stop running upward; When the tower crane triggers the lower stop limit, the programmable controller sends a command to the inverter, and the inverter controls the motor to stop running downward; When the tower crane triggers the torque limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum movement frequency of the luffing trolley and the boom is adjusted according to the ratio of the torque limit amplitude; When the tower crane triggers the weight limit, the programmable controller controls the frequency converter, and the maximum frequency of the lifting and lowering movements is changed to the base frequency of the lifting motor. The maximum movement frequency of the luffing trolley and the boom is adjusted according to the proportion of the weight limit.

[0009] The maximum operating frequency of the motor output by the linkage table is the maximum gear position when the linkage table outputs in stages.

[0010] When the tower crane is triggered 100% When the torque is limited, the programmable controller controls the frequency converter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the luffing trolley stops shifting outward, and the maximum frequency of the inward movement of the luffing trolley is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor.

[0011] When the tower crane triggers the 90% torque limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum frequency of the outward movement of the luffing trolley is changed to 15% of the base frequency of the luffing motor, and there is no restriction on inward movement.

[0012] When the tower crane triggers the 100% weight limit, the programmable controller controls the frequency converter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the maximum frequency of the outward movement of the luffing trolley is changed to 15% of the base frequency of the luffing motor, and the maximum frequency of the inward movement is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor.

[0013] When the tower crane triggers the 90% weight limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum frequency of the outward movement of the luffing trolley is changed to 30% of the base frequency of the luffing motor, and there is no restriction on inward movement.

[0014] The present invention has the following advantages: the tower crane stepless speed regulation control system and method of the present invention realizes stepless and smooth speed regulation of the tower crane through communication between a CAN-type linkage table, a PLC controller and a frequency converter, and outputs any frequency between 0 and the maximum allowable output frequency through an operating lever to achieve more precise control; at the same time, when the tower crane is operating under special working conditions, the output frequency of the linkage table is proportionally reduced through the PLC controller, thereby realizing stepless speed regulation under the condition of speed limit of the tower crane, and realizing all-round stepless speed regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the accompanying drawings described below are only some embodiments. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0016] In the attached picture: Figure 1 It is a system principle diagram of the present invention; Figure 2 It is a structural schematic diagram of the linkage platform of the present invention.

[0017] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0019] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] like Figure 1 to Figure 2A tower crane stepless speed regulation control system shown in the figure comprises a programmable controller, the programmable controller is connected with a linkage table, a frequency converter and a position sensor, the frequency converter is connected with a motor, the motor is provided with a speed encoder, and the speed encoder is connected with the frequency converter. The linkage table is a CAN type linkage table, and the linkage table is connected with the programmable controller through a CAN line. The tower crane stepless speed regulation control system of the present invention comprises a programmable controller (PLC), a linkage table, a position sensor, a frequency converter, a motor and a speed encoder, wherein the CAN type linkage table, the position sensor and the frequency converter are connected with the PLC controller through a CAN line, CAN communication is used, the intermediate relay in the gear information transmission line is cancelled, and the fault point is reduced, the CAN type linkage table is used to transmit the control signal to the PLC, the position sensor is used to detect the limit signal, and transmit the position information to the PLC, the PLC makes a judgment according to the signal input by the linkage table and the position sensor, and transmits the result to the frequency converter for controlling the rotation of the motor; the speed encoder is used to detect the speed of the motor, and always feeds back the speed of the motor to the frequency converter to realize the closed-loop control of the motor speed. During the operation of the tower crane, the driver controls the operation of the tower crane by controlling the joystick of the linkage table. When the tower crane is operating normally, the PLC controller sets the maximum operating frequency of the motor output by the linkage table to 100% frequency (that is, the fifth gear or the maximum gear when the linkage table outputs in stages). At this time, the tower crane can achieve stepless speed regulation of the motor from 0% frequency to 100% frequency within the full deflection range of the linkage table operating lever; when the tower crane limiter is triggered or the tower crane enters a special working condition, the PLC controller will proportionally reduce the output frequency of the CAN linkage table. At this time, the tower crane can still use the full deflection range of the linkage table operating lever to achieve stepless speed regulation of the motor from 0% frequency to the maximum limit frequency, realizing stepless speed regulation control of the three major mechanisms of the tower crane, so that the tower crane mechanism can smoothly and stably increase from zero speed to the highest speed and stably decrease from the highest speed to zero speed, thereby improving the working efficiency and working stability of the tower crane.

[0022] like Figure 1 A tower crane stepless speed regulation control system is shown, and the model of the programmable controller is XG-qIMCA3256GS.

[0023] like Figure 2 A tower crane stepless speed regulation control system is shown, wherein the linkage platform includes a control panel, and the control panel is connected with a variable amplitude potentiometer and a rotary potentiometer. The linkage platform of the present invention includes a control panel, a variable amplitude potentiometer and a rotary potentiometer. When the tower crane driver turns the handle, the potentiometer built into the linkage platform converts the amplitude of the operating lever offset into an analog signal, and the analog signal is converted into a CAN communication signal through the control panel in the linkage platform, and is transmitted to the PLC controller, and then transmitted to the frequency converter by the PLC controller to control the motor operation, thereby realizing stepless speed regulation of the tower crane.

[0024] The use method of the tower crane stepless speed regulation control system of the present invention includes the normal operation condition and the limit condition of the tower crane. The limit condition is divided into deceleration limit, upper stop limit, lower stop limit, stop limit, torque limit and weight limit. The specific conditions are as follows: When the tower crane is operating normally, the programmable controller sets the maximum operating frequency of the motor output by the linkage table to 100% frequency, that is, the maximum operating frequency of the motor output by the linkage table is the fifth gear or the maximum gear when the linkage table is output in gears. At this time, the tower crane driver can achieve stepless speed regulation of the motor from 0% frequency to 100% frequency within the entire deflection range of the linkage table operating lever.

[0025] When the tower crane triggers the deceleration limit, the programmable controller will proportionally reduce the output frequency of the linkage table to achieve the purpose of low-speed operation of the motor. At this time, the tower crane driver can still use the full deflection range of the linkage table operating lever to achieve stepless speed regulation of the motor from 0% frequency to the maximum limit frequency. When the tower crane hook runs upward to the ascending deceleration limit, the PLC will set the maximum frequency of the hoisting motor to 20% of the base frequency (base frequency refers to the rated frequency of the motor). At this time, the tower crane driver can achieve output at any speed between 0-20% of the base frequency.

[0026] When the tower crane triggers the upper stop limit, the programmable controller sends a command to the frequency converter, and the frequency converter controls the motor to stop running upward, but does not affect the downward movement of the tower crane; when the tower crane triggers the lower stop limit, the programmable controller sends a command to the frequency converter, and the frequency converter controls the motor to stop running downward, but does not affect the upward movement of the tower crane; when the stop limit is triggered, the control logic is the same as the control logic during graded speed regulation, among which the correspondence between the stepless speed regulation frequency and the graded speed regulation gear is: for lifting, 20% of the base frequency is equivalent to the 1st gear, 50% of the base frequency is equivalent to the 2nd gear, the base frequency is equivalent to the 3rd gear, the maximum frequency is 75% equivalent to the 4th gear, and the maximum frequency is equivalent to the 5th gear; for rotation and amplitude variation, 15% of the base frequency is equivalent to the 1st gear, 30% is equivalent to the 2nd gear, 50% is equivalent to the 3rd gear, 75% is equivalent to the 4th gear, and 100% is equivalent to the 5th gear.

[0027] When the tower crane triggers the torque limit, the programmable controller controls the inverter to change the maximum frequency of the lifting and lowering movement to the base frequency of the lifting motor, and the maximum movement frequency of the luffing trolley and the boom is adjusted according to the ratio of the torque limit amplitude. When the tower crane triggers the 100% torque limit, the programmable controller controls the inverter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the luffing trolley stops the outward amplitude change, and the maximum frequency of the inward movement of the luffing trolley is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor. When the tower crane triggers the 90% torque limit, the programmable controller controls the inverter to change the maximum frequency of the lifting and lowering movement to the base frequency of the lifting motor, and the maximum frequency of the outward movement of the luffing trolley is changed to 15% of the base frequency of the luffing motor, and there is no limit on the inward movement.

[0028] When the tower crane triggers the weight limit, the programmable controller controls the inverter, and the maximum frequency of the lifting and lowering movement is changed to the base frequency of the lifting motor, and the maximum movement frequency of the luffing trolley and the boom is adjusted according to the proportion of the weight limit. When the tower crane triggers the 100% weight limit, the programmable controller controls the inverter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the maximum frequency of the luffing trolley moving outward is changed to 15% of the base frequency of the luffing motor, and the maximum frequency of the inward movement is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor. When the tower crane triggers the 90% weight limit, the programmable controller controls the inverter to change the maximum frequency of the lifting and lowering movement to the base frequency of the lifting motor, and the maximum frequency of the luffing trolley moving outward is changed to 30% of the base frequency of the luffing motor, and there is no limit on the inward movement.

[0029] The present invention discloses a tower crane stepless speed regulation control system and method. The linkage table uses a CAN linkage table, and the position information of the operating lever is converted into analog information through a built-in potentiometer, and then converted into a CAN signal through a control board, so that stepless speed is realized in the gear input; after the PLC controller receives the speed limit information of the safety device, the output frequency of the CAN linkage table is proportionally reduced, so that the full moving range of the joystick can still be used for speed regulation under the speed limit; the output frequency ratio of the linkage table can be changed by changing the maximum allowable frequency through the PLC controller, and the change value can be set as needed, without additional line changes. In the control system, the main components communicate through the CAN line, and there is no need to use a resistance loop for shunting when the tower crane is limited in speed, thereby reducing the fault point and facilitating later maintenance. When the tower crane is working normally, the linkage table operating lever is used to realize stepless speed regulation from 0-100% frequency. When the tower crane is running under special working conditions, the output frequency of the linkage table is proportionally reduced through the PLC controller, so that stepless speed regulation is realized under the speed limit of the tower crane, and all-round stepless speed regulation is truly realized, making the control more precise.

[0030] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0031] In addition, those skilled in the art will understand that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments also means being within the scope of protection of the present invention and forming different embodiments. For example, in the above embodiments, those skilled in the art can use them in combination according to the known technical solutions and the technical problems to be solved by this application.

[0032] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A tower crane stepless speed regulation control system, characterized in that: The invention comprises a programmable controller, wherein the programmable controller is connected with a linkage platform, a frequency converter and a position sensor, the frequency converter is connected with a motor, the motor is provided with a speed measuring encoder, and the speed measuring encoder is connected with the frequency converter.

2. A tower crane stepless speed regulation control system as claimed in claim 1, characterized in that: The model of the programmable controller is XG-qIMCA 3256GS.

3. A tower crane stepless speed control system as claimed in claim 1, characterized in that: The linkage platform is a CAN type linkage platform, and the linkage platform is connected to a programmable controller via a CAN line.

4. A tower crane stepless speed control system as claimed in claim 1, characterized in that: The linkage platform comprises a control panel, and the control panel is connected with a variable amplitude potentiometer and a rotary potentiometer.

5. A method for using the tower crane stepless speed regulation control system according to claim 1, characterized in that: Including normal operation and limit operation of tower crane. When the tower crane is operating normally, the programmable controller sets the maximum operating frequency of the motor output by the linkage table to 100% frequency. At this time, the tower crane driver can achieve stepless speed regulation of the motor from 0% frequency to 100% frequency within the full deflection range of the linkage table operating lever; When the tower crane triggers the deceleration limit, the programmable controller will proportionally reduce the output frequency of the linkage table; When the tower crane triggers the upper stop limit, the programmable controller sends a command to the inverter, and the inverter controls the motor to stop running upward; When the tower crane triggers the lower stop limit, the programmable controller sends a command to the inverter, and the inverter controls the motor to stop running downward; When the tower crane triggers the torque limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum movement frequency of the luffing trolley and the boom is adjusted according to the ratio of the torque limit amplitude; When the tower crane triggers the weight limit, the programmable controller controls the frequency converter, and the maximum frequency of the lifting and lowering movements is changed to the base frequency of the lifting motor. The maximum movement frequency of the luffing trolley and the boom is adjusted according to the proportion of the weight limit.

6. The method for using the tower crane stepless speed regulation control system according to claim 5, characterized in that: The maximum operating frequency of the motor output by the linkage table is the maximum gear position when the linkage table outputs in stages.

7. The method for using the tower crane stepless speed regulation control system according to claim 5, characterized in that: When the tower crane triggers the 100% torque limit, the programmable controller controls the frequency converter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the luffing trolley stops shifting outward, and the maximum frequency of the inward movement of the luffing trolley is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor.

8. The method for using the tower crane stepless speed regulation control system according to claim 5, characterized in that: When the tower crane triggers the 90% torque limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum frequency of the outward movement of the luffing trolley is changed to 15% of the base frequency of the luffing motor, and there is no restriction on inward movement.

9. The method for using the tower crane stepless speed regulation control system according to claim 5, characterized in that: When the tower crane triggers the 100% weight limit, the programmable controller controls the frequency converter to stop the lifting motor from moving upward, and the maximum frequency of lifting and lowering is changed to the base frequency of the lifting motor; the maximum frequency of the outward movement of the luffing trolley is changed to 15% of the base frequency of the luffing motor, and the maximum frequency of the inward movement is changed to 50% of the base frequency of the luffing motor; the maximum frequency of the left and right rotation of the boom is changed to 50% of the base frequency of the rotation motor.

10. The method for using the tower crane stepless speed regulation control system according to claim 5, characterized in that: When the tower crane triggers the 90% weight limit, the programmable controller controls the frequency converter to change the maximum frequency of the lifting and lowering movements to the base frequency of the lifting motor, and the maximum frequency of the outward movement of the luffing trolley is changed to 30% of the base frequency of the luffing motor, and there is no restriction on inward movement.

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