A method for controlling anti-sway during driving

Abstract

The present invention relates to a method for controlling anti-sway of a traveling crane. The method is based on an electromechanical integrated anti-sway control system of an inertial measurement unit. By actively and timely monitoring the motion state of the suspended load through the inertial measurement unit, a closed-loop control method is adopted. According to the swing speed and position of the suspended load, the servo system is driven to control the motion of the traveling crane and generate inertial force. The technical solution proposed by the present invention can respond quickly, has an ideal anti-sway effect, improves the safety and stability of the lifting operation, and meets the requirements of industrial production.

Description

Technical Field

[0001] The present invention belongs to the field of hoisting machinery, and particularly relates to a mechatronic anti-sway control method based on an inertial measurement unit. Background Art

[0002] During the operation of a traveling crane, due to the acceleration or deceleration during the operation of the traveling crane, or the influence of external forces on the suspended load, the suspended load will swing. This not only increases the difficulty of unloading the suspended load, but also brings unsafe factors to the hoisting operation. Therefore, during hoisting operations, it is crucial to control the swing of the suspended load. For this reason, various anti-sway methods have been proposed.

[0003] For example, in the visual sensor electronic anti-sway technology, the method is as follows: The information detected by sensors and detection elements is transmitted to the microcomputer in the control system. After being processed by the internal control software of the microcomputer, the optimal control parameters (such as PID control parameters) are provided to the trolley speed control system. By adjusting the speed and direction of the traveling crane, the operation of the traveling crane is controlled to reduce the swing amplitude of the spreader and the load. However, visual sensors are often expensive, and in adverse weather conditions (such as thick fog, heavy rain, direct sunlight, etc.), it is difficult for visual sensors to accurately measure, and the control effect is not ideal.

[0004] The anti-sway control technology based on a micro-accelerometer timely detects the acceleration of the traveling crane during operation and estimates the swing angle of the suspended load. By establishing a closed-loop control system, the trolley speed command is corrected in a timely manner according to the swing amplitude of the suspended load to achieve anti-sway control. This control method is only applicable to the swing of the suspended load caused by acceleration and deceleration during the operation of the traveling crane, and cannot solve the technical problem of the swing of the suspended load caused by external forces during the uniform operation of the traveling crane. Summary of the Invention

[0005] Object of the Invention: In order to overcome the defects and deficiencies of the prior art, the present invention proposes a mechatronic anti-sway control method based on an inertial measurement unit, actively and timely monitors the motion state of the suspended load, adopts a closed-loop control method, and drives the servo traveling crane according to the swing speed and position to generate an inertial force, with a fast response, an ideal anti-sway effect, improving the safety and stability of hoisting operations, and meeting the requirements of industrial production.

[0006] Technical Solution: To achieve the above object, the following technical solutions are adopted by the present invention:

[0007] A control method for preventing the sway of a traveling crane is proposed. The control system consists of a PLC (programmable logic controller) main control unit, an inertial measurement unit, a servo system, and a traveling crane. The inertial measurement unit is fixedly connected to the hook of the traveling crane and transmits the measured values to the PLC main control unit in real time through serial communication. The inertial measurement unit measures the real-time swing angle θ and real-time swing speed ω of the suspended load in real time and transmits the θ and ω to the PLC main control unit in real time. The PLC controls the movement of the traveling crane through the servo system according to the detection data of the inertial measurement unit. After calculation, when certain conditions are met, it can achieve the effect of anti-sway braking. The control steps are as follows:

[0008] (1) When the inertial measurement unit detects the swing of the suspended load, after calculation by the PLC main control unit, when the start condition or the forward commutation condition is met, the servo system is controlled within the time t to make the traveling crane accelerate in the positive direction, and the final speed is the maximum linear speed value Vc of the traveling crane, Vc = K * Vt, where K is a coefficient with a value range of (0.5 - 4), and Vt is the maximum linear speed of the simple pendulum;

[0009] (2) When detecting the negative commutation of the suspended load, after calculation by the PLC main control unit, when the negative commutation condition is met, the servo system is controlled within the time t to make the traveling crane decelerate in the negative direction, and the final speed is the minimum linear speed value -Vc of the traveling crane, -Vc = K * -Vt, where K is a coefficient with a value range of (0.5 - 4), and -Vt is the minimum linear speed of the simple pendulum;

[0010] (3) The above steps (1) and (2) are used to control the traveling crane to follow the reciprocating acceleration and deceleration movement of the suspended load in a closed-loop manner. When the stop condition is met, the main control PLC unit immediately stops the servo system;

[0011] Further, the start condition or the forward commutation condition is set as ω > +0.01 rad / s, θ < -0.1 rad;

[0012] The negative commutation condition is set as ω < -0.01 rad / s, θ > +0.1 rad;

[0013] The stop condition is set as -0.01 rad / s < ω < +0.01 rad / s, -0.1 rad < θ < +0.1 rad;

[0014] Further, the control method for preventing the sway of the traveling crane includes: the time t is set as 1 / 4 (T / 4) of the swing period T of the suspended load;

[0015] Further, when the start condition is met, that is, within the time period of 0 to T / 4, T / 4 = t1 + t2 + t3 / 2, where t1 is the delay time of the PLC signal, t2 is the extended time for the PLC to start the hoist, and t3 is the acceleration and deceleration time of the hoist. Adjust t2 in the PLC so that the hoist starts to accelerate from 0 to Vc at T / 4 - t3 / 2 and completes the acceleration from 0 to Vc at T / 4 + t3 / 2, with an acceleration of +a, generating a reverse inertial force -F acting on the suspended load. After that, the hoist moves forward at a constant speed of Vc, where Vc is the maximum linear speed value of the suspended load;

[0016] Further, when the negative commutation condition is met, that is, within the time period of T / 4 to 3T / 4, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, where t1 is the delay time of the PLC signal, t4 is the extended time for the PLC to commutate the hoist, and t3 is the acceleration and deceleration time of the hoist. Adjust t4 in the PLC so that t4 = t2 - t3 / 2, making the hoist start to decelerate from Vc to 0 at 3T / 4 - t3, start to decelerate from 0 to -Vc at 3T / 4, and complete the deceleration from 0 to -Vc at 3T / 4 + t3, with an acceleration of -a, generating an inertial force F acting on the suspended load. After that, the hoist moves forward at a constant speed of -Vc;

[0017] Further, when the positive commutation condition is met, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, that is, within the time period of 3T / 4 to 5T / 4, where t1 is the delay time of the PLC signal, t4 is the extended time for the PLC to commutate the hoist, and t3 is the acceleration and deceleration time of the hoist. Adjust t4 in the PLC so that t4 = t2 - t3 / 2, making the hoist start to accelerate from -Vc to 0 at 5T / 4 - t3, start to accelerate from 0 to Vc at 5T / 4, and complete the acceleration from 0 to Vc at 5T / 4 + t3, with an acceleration of +a, generating a reverse inertial force -F acting on the suspended load. After that, the hoist moves forward at a constant speed of Vc.

[0018] Beneficial effects: The anti-sway system of the hoist composed of the above-mentioned inertial measurement unit, servo unit, and PLC main control unit has a simple structure and fast response. By adjusting and setting the control time through the PLC, and reasonably setting the control position and control speed, the direction and magnitude of the inertial force are accurately controlled, achieving a fast anti-sway braking effect. Description of the Drawings

[0019] Figure 1 It is a diagram of the anti-sway control system of the present invention;

[0020] Figures 2-4 It is a diagram of the anti-sway control method of the present invention. Detailed Embodiments

[0021] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] When the traveling crane accelerates or decelerates, or there is an external force interfering with the suspended load, it will cause the suspended load to swing. At this time, the swing is a simple pendulum motion in a non-inertial frame with the traveling crane as the reference system.

[0023] Refer to Figure 1 , a traveling crane anti-sway control system proposed in this embodiment. The control system consists of a PLC (programmable logic controller) main control unit, an inertial measurement unit, a servo system, and a traveling crane. The servo system can be an inverter for driving an AC asynchronous motor or a servo unit for driving an AC synchronous motor. The inertial measurement unit is a gyroscope, which is fixedly connected to the hook of the traveling crane and transmits the measured values to the PLC main control unit in real time through serial communication. The gyroscope measures the real-time swing angle θ and real-time swing speed ω of the suspended load in real time, and transmits the θ and ω to the PLC main control unit in real time through the RS422 serial communication interface. According to the detection data of the gyroscope, after calculation, when certain conditions are met, the PLC controls the movement of the traveling crane through the servo system to achieve the effect of anti-sway braking, including the following control steps:

[0024] (1) When the gyroscope detects the swing of the suspended load, after calculation by the PLC main control unit, when the start condition or the forward commutation condition is met, within the time t, the servo system is controlled to make the traveling crane accelerate in the direction of the simple pendulum motion, and the final speed is the maximum linear speed value Vc of the traveling crane, Vc = K * Vt, where K is a coefficient with a value range of (0.5~4), and Vt is the maximum linear speed of the simple pendulum. The start condition or the forward start condition in this embodiment is the same, that is, the swing speed ω of the suspended load > +0.01 rad / s and the swing angle θ < -0.1 rad;

[0025] (2) When detecting the negative commutation of the suspended load, after calculation by the PLC main control unit, when the negative commutation condition is met, within the time t, the servo system is controlled to make the traveling crane decelerate in the negative direction, and the final speed is the minimum linear speed value -Vc of the traveling crane, -Vc = K * -Vt, where K is a coefficient with a value range of (0.5~4), and -Vt is the minimum linear speed of the simple pendulum. The negative commutation condition in this embodiment is that the swing speed ω of the suspended load < -0.01 rad / s and the swing angle θ > +0.1 rad;

[0026] (3) The above steps (1) and (2) are used to control the traveling crane to follow the reciprocating acceleration and deceleration of the suspended load in a closed-loop manner. When the stop condition is met, the main control PLC unit immediately stops the servo system. The stop condition in this embodiment is -0.01 rad / s < ω < +0.01 rad / s and -0.1 rad < θ < +0.1 rad;

[0027] Refer to Figures 2-4, further clarify the control method of the present invention, where T is the period of the pendulum, and t = T / 4 is set as the control condition.

[0028] Refer to Figure 2 , when the start condition is satisfied, that is, within the time of 0 to T / 4, T / 4 = t1 + t2 + t3 / 2, where t1 is the delay time of the PLC signal, t2 is the extension time for the PLC to start the crane, and t3 is the acceleration and deceleration time of the crane. Adjust t2 in the PLC so that the crane starts to accelerate from 0 to Vc at T / 4 - t3 / 2 and completes the acceleration from 0 to Vc at T / 4 + t3 / 2, with an acceleration of +a, so as to generate a reverse inertial force -F acting on the suspended load. Then the crane moves forward at a constant speed of Vc, where Vc is the maximum linear speed value of the crane;

[0029] Refer to Figure 3 , when the negative commutation condition is satisfied, that is, within the time of T / 4 to 3T / 4, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, where t1 is the delay time of the PLC signal, t4 is the extension time for the PLC to commutate the crane, and t3 is the acceleration and deceleration time of the crane. Adjust t4 in the PLC so that t4 = t2 - t3 / 2, so that the crane starts to decelerate from Vc to 0 at 3T / 4 - t3, starts to decelerate from 0 to -Vc at 3T / 4, and completes the deceleration from 0 to -Vc at 3T / 4 + t3, with an acceleration of -a, so as to generate an inertial force F acting on the suspended load. Then the crane moves forward at a constant speed of -Vc;

[0030] Refer to Figure 4 , when the positive commutation condition is satisfied, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, that is, within the time of 3T / 4 to 5T / 4, where t1 is the delay time of the PLC signal, t4 is the extension time for the PLC to commutate the crane, and t3 is the acceleration and deceleration time of the crane. Adjust t4 in the PLC so that t4 = t2 - t3 / 2, so that the crane starts to accelerate from -Vc to 0 at 5T / 4 - t3, starts to accelerate from 0 to Vc at 5T / 4, and completes the acceleration from 0 to Vc at 5T / 4 + t3, with an acceleration of +a, so as to generate a reverse inertial force -F acting on the suspended load. Then the crane moves forward at a constant speed of Vc.

[0031] Through the repeated action of the above inertial force at the lowest point of the pendulum movement, the kinetic energy of the suspended load is rapidly reduced, achieving the effect of anti-sway braking.

[0032] The present invention is not limited to the above best implementation mode. Anyone can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as it has a technical solution identical or similar to the present application, it falls within the protection scope of the present invention.

Claims

1. A method for controlling anti-sway of a traveling crane, characterized in that, The control system consists of a PLC main control unit, an inertial measurement unit, a servo system, and a traveling crane. The inertial measurement unit is fixedly connected to the hook of the traveling crane and transmits the measured values to the PLC main control unit in real time through serial communication. The inertial measurement unit measures the real-time swing angle θ and real-time swing speed ω of the suspended load in real time and transmits θ and ω to the PLC main control unit in real time. The PLC main control unit controls the movement of the traveling crane through the servo system after calculation based on the detection data of the inertial measurement unit. The control steps are as follows: (1) When the inertial measurement unit detects the swing of the suspended load, after calculation by the PLC main control unit, when the start condition or the forward commutation condition is met, the servo system is controlled within the time t to make the traveling crane accelerate in the positive direction, and the final speed is the maximum linear speed value Vc of the traveling crane, Vc = K * Vt, where K is a coefficient with a value range of 0.5 to 4, and Vt is the maximum linear speed of the simple pendulum; the time t is set to 1 / 4 of the swing period T of the suspended load, that is, T / 4; When the start condition is met, that is, within the time of 0 to T / 4, T / 4 = t1 + t2 + t3 / 2, where t1 is the PLC signal delay time, t2 is the extended time for the PLC main control unit to start the traveling crane, and t3 is the acceleration and deceleration time of the traveling crane. Adjust t2 in the PLC main control unit so that the traveling crane starts to accelerate from 0 to Vc at T / 4 - t3 / 2 and completes the acceleration from 0 to Vc at T / 4 + t3 / 2, with an acceleration of +a, so as to generate a reverse inertial force -F acting on the suspended load. Then the traveling crane moves forward at a constant speed of Vc, where Vc is the maximum linear speed value of the suspended load; When the forward commutation condition is met, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, that is, within the time of 3T / 4 to 5T / 4, where t1 is the PLC signal delay time, t4 is the extended time for the PLC main control unit to commutate the traveling crane, and t3 is the acceleration and deceleration time of the traveling crane. Adjust t4 in the PLC main control unit so that t4 = t2 - t3 / 2, so that the traveling crane starts to accelerate from -Vc to 0 at 5T / 4 - t3, starts to accelerate from 0 to Vc at 5T / 4, and completes the acceleration from 0 to Vc at 5T / 4 + t3, with an acceleration of +a, so as to generate a reverse inertial force -F acting on the suspended load. Then the traveling crane moves forward at a constant speed of Vc; (2) When the negative commutation of the suspended load is detected, after calculation by the PLC main control unit, when the negative commutation condition is met, the servo system is controlled within the time t to make the traveling crane decelerate in the negative direction, and the final speed is the minimum linear speed value -Vc of the traveling crane, -Vc = K * -Vt, where K is a coefficient with a value range of 0.5 to 4, and -Vt is the minimum linear speed of the simple pendulum; When the negative commutation condition is satisfied, that is, within the time of T / 4 to 3T / 4, T / 4 = t1 + t4 + t3 / 2 + t3 / 2, where t1 is the PLC signal delay time, t4 is the extended time for the PLC main control unit to reverse the traveling crane, t3 is the acceleration and deceleration time of the traveling crane. In the PLC main control unit, adjust t4 so that t4 = t2 - t3 / 2, so that the traveling crane starts to decelerate from Vc to 0 at 3T / 4 - t3, starts to decelerate from 0 to -Vc at 3T / 4, and completes the deceleration from 0 to -Vc at 3T / 4 + t3, with an acceleration of -a, so as to generate a reverse inertial force F acting on the suspended load. After that, the traveling crane moves forward at a constant speed of -Vc, where -Vc is the minimum linear velocity value of the suspended load; (3) The above steps (1) and (2) are used to close-loop control the traveling crane to follow the suspended load for reciprocating acceleration and deceleration motion. When the stop condition is satisfied, the PLC main control unit immediately stops the servo system.

2. The anti-sway control method for a traveling crane according to claim 1, wherein The start condition or the positive commutation condition is set as ω > +0.01 rad / s, θ < -0.1 rad; the negative commutation condition is set as ω < -0.01 rad / s, θ > +0.1 rad; the stop condition is set as -0.01 rad / s < ω < +0.01 rad / s, -0.1 rad < θ < +0.1 rad.

3. The anti-sway control method for the traveling crane according to claim 1, wherein The inertial measurement unit is a gyroscope.

4. The anti-sway control method for the traveling crane according to claim 1, characterized in that, The servo system is an inverter.

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