A novel torque control method for marine cranes

Abstract

This invention relates to a novel torque control method for marine cranes. It employs an absolute encoder to collect the dynamic angular displacement *s* of the boom in real time, and a load cell to collect the load weight *m* tons. The initial boom position is set to *a0* = 0 degrees, and the dynamic boom angle *a* = *f(s)* is calculated. Based on the boom-load characteristic curve analyzed from the crane's structural parameters, a polynomial is selected for the trend line, and the fitting degree R² = 0.9989 is obtained. The required accuracy is R = f(m) = A1*m³ + B1*m² + C1*m + D1, where A1 = -0.0014, B1 = 0.1927, C1 = -9.0764, and D1 = 176.78. Based on the load-boost characteristic curve analyzed from the crane's structural parameters, a polynomial is selected for the trend line, and the fitting degree R² is obtained. 2 =0.9991, the required precision is m=f(R)=A2*R 3 +B2*R 2 The formula is: +C2*R+D2, where A2=-0.0231, B2=2.6239, C2=-100.18, and D2=1317.6. This method utilizes an encoder to monitor the luffing angle and calculate the amplitude, achieving efficient and superior torque control to complete tasks such as luffing and lifting of cranes.

Description

Technical Field

[0001] This invention belongs to the technical field of marine lifting equipment, specifically relating to a novel torque control method for marine cranes. Background Technology

[0002] Traditional torque converter control methods, based on load-amplitude characteristics derived from angle sensors, are significantly affected by sensor detection accuracy, zero-point stability, and electromagnetic interference, resulting in large torque converter control errors. Furthermore, they are susceptible to external environmental influences and struggle to meet high-precision control requirements. Therefore, a torque converter control method based on absolute encoders addresses these shortcomings of traditional methods. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a new torque control method for marine cranes. This method uses an encoder to monitor the luffing angle and calculate the amplitude, thereby achieving efficient and superior torque control and completing the crane's luffing and lifting operations.

[0004] To address the above technical problems, this invention provides a novel torque control method for marine cranes, comprising the following steps.

[0005] Step S1: Use an absolute encoder to collect the dynamic angular displacement s of the luffing boom in real time, and a load cell to collect the load weight m tons. Set the initial luffing position of the crane a0 = 0 degrees, and calculate the dynamic luffing angle a = f(s);

[0006] Step S2: Analyze the amplitude-load characteristic curve based on the crane's structural parameters. The load-amplitude characteristic curve is a polynomial, and the goodness of fit R² = 0.9989 is adjusted. The required accuracy is R = f(m) = A1*m. 3 +B1*m 2 +C1*m+D1, where A1=-0.0014, B1=0.1927, C1=-9.0764, D1=176.78;

[0007] Step S3: Analyze the load-amplitude characteristic curve based on the crane's structural parameters. The load-amplitude characteristic curve is obtained by using a polynomial and adjusting the fit R. 2 =0.9991, the required precision is m=f(R)=A2*R 3 +B2*R 2 +C2*R+D2, where A2=-0.0231, B2=2.6239, C2=-100.18, D2=1317.6.

[0008] The technical solution further defined by the present invention is: initial position: the crane boom is placed at a 0-degree position or at an initial position of angle a0.

[0009] Further, for the dynamic position: lift the crane boom to the dynamic position, generating a luffing angular displacement s. The PLC calculates that the luffing angle a = f(s), and the luffing amplitude R = f(a).

[0010] Further, in the execution state, the PLC logic operation determines that: when R < R(m), normal luffing descent is allowed; when R >= R(m), luffing descent is prohibited; when m <= m(R), the hook is normally lifted; when m > m(R), hook lifting is prohibited.

[0011] The beneficial effects of the present invention are as follows:

[0012] Using an absolute encoder to collect the luffing angular displacement has the advantages of high control precision, strong anti-interference ability, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the initial position of the luffing of the crane of the present invention;

[0014] Figure 2 It is a schematic diagram of the dynamic position of the luffing of the crane of the present invention;

[0015] Figure 3 It is a precision control curve graph of step S2 of the method of the present invention;

[0016] Figure 4 It is a precision control curve graph of step S3 of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Embodiment

[0018] Please refer to Figures 1-2 , this embodiment provides a new torque control method for a marine crane, which includes the following steps

[0019] Step S1: Use an absolute encoder to collect the dynamic angular displacement s of the luffing boom in real time, use a load cell to collect the load weight m tons, set the initial position of the crane luffing a0 = 0 degrees, and calculate the dynamic luffing angle a = f(s);

[0020] Step S2: Analyze the amplitude-load characteristic curve according to the crane structure parameters. The load-amplitude characteristic curve uses a polynomial, and the adjusted fitting degree R2 = 0.9989. The accuracy requirement is R = f(m) = A1*m 3 + B1*m 2 + C1*m + D1, where A1 = -0.0014, B1 = 0.1927, C1 = -9.0764, D1 = 176.78, as Figure 3 ;

[0021] Step S3: Analyze the load - amplitude characteristic curve based on the crane structure parameters. The load - amplitude characteristic curve adopts a polynomial, and after adjustment, the fitting degree R2 = 0.9991. The accuracy requirement is m = f(R)=A2*R 3 +B2*R 2 +C2*R + D2, where A2=-0.0231, B2 = 2.6239, C2=-100.18, D2 = 1317.6, as Figure 4 .

[0022] Initial position: Place the crane boom at the 0 - degree position or use the angle a0 as the initial position.

[0023] Dynamic position: Lift the crane boom to the dynamic position, generating a luffing angular displacement s. The PLC calculates: the luffing angle a = f(s), and the luffing amplitude R = f(a).

[0024] During the execution state, the PLC logical operation determines that: when R < R(m), the normal luffing descends; when R >= R(m), the luffing descent is prohibited; when m <= m(R), the hook is lifted normally; when m > m(R), the hook lift is prohibited.

[0025] This method uses an absolute encoder to monitor the luffing boom angular displacement in real - time, a load cell to monitor the load weight, and through the PLC algorithm, the luffing angle and luffing amplitude are calculated in real - time. After being analyzed by the load - amplitude non - linear algorithm, the safe working load and amplitude are given to the crane control system to perform luffing and hoisting operations.

[0026] This method can use the encoder to monitor the luffing angle and calculate the amplitude, achieve efficient and superior torque control, and complete operations such as crane luffing and hoisting.

[0027] In addition to the above - mentioned embodiments, the present invention can also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A novel torque control method for marine cranes, characterized in that, It includes the following steps: Step S1: Use an absolute encoder to collect the dynamic angular displacement s of the luffing jib in real time, use a load cell to collect the load weight of m tons, set the initial position of the crane luffing a0 = 0 degrees, and calculate the luffing dynamic angle a = f(s); Step S2: Analyze the amplitude-load characteristic curve based on the crane's structural parameters. The amplitude-load characteristic curve is obtained by using a polynomial and adjusting the fit R. 2 =0.9989, determine the safe working radius R (m): R (m) = A1 * m 3 +B1*m 2 +C1*m+D1, where A1=-0.0014, B1=0.1927, C1=-9.0764, D1=176.78; Step S3: Analyze the load-amplitude characteristic curve based on the crane's structural parameters. The load-amplitude characteristic curve is obtained by using a polynomial and adjusting the fit R. 2 =0.9991, determine the safe workload m(R): m(R) = A2*R 3 +B2*R 2 +C2*R+D2, where A2=-0.0231, B2=2.6239, C2=-100.18, D2=1317.6; Lift the crane jib to the dynamic position to generate the luffing dynamic angular displacement s. The PLC calculates that the luffing dynamic angle a = f(s) and the luffing amplitude R = f(a). In the execution state, the PLC logical operation determines that when R < R(m), the normal luffing descends; when R >= R(m), the luffing descent is prohibited; when m <= m(R), the hook is normally lifted; when m > m(R), the hook lift is prohibited.

2. The novel torque control method for a marine crane according to claim 1, characterized in that, Initial position: Place the crane jib at the 0-degree position or use the angle a0 as the initial position.

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