Online adjusting method for crank throw gap in marine crankshaft machining

Abstract

The invention discloses a marine crankshaft measuring and adjusting method based on dynamic priority and multi-support cooperative decoupling, and belongs to the technical field of high-end equipment manufacturing. Aiming at the problems of low adjustment efficiency and insufficient precision caused by a complex structure and a support coupling effect in the processing of the asymmetric large marine crankshaft, the invention provides the following innovations: 1, a dynamic priority adjustment strategy: dynamically calculating the adjustment priority of each journal according to a gear throwing difference (delta S) and a jerk value (delta) which are detected in real time, and preferentially processing the journals in a high-risk area; 2, multi-support cooperative decoupling control: realizing accurate decoupling of multi-support displacement through rigidity influence matrix modeling, and eliminating coupling deformation;

Description

Technical Field

[0001] This invention belongs to the field of precision machining technology for marine crankshafts, specifically relating to an adjustment method and system for dynamic priority and multi-support collaborative decoupling of asymmetric large marine crankshafts, applicable to the efficient and high-precision machining of large marine diesel engine crankshafts. Background Technology Traditional machining and inspection of large marine crankshafts employs a fixed sequence of point-by-point adjustments (e.g., 1#→2#→3#→4#→5#→6#), which has the following drawbacks: adjustments in a preset sequence cannot respond to sudden deformations, leading to accumulated errors; single-point adjustments can cause secondary deformation of adjacent journals; and efficiency is low, with finishing cycles lasting up to 10 days. While existing patents (e.g., CN202510158999.0) propose online inspection technology, they do not address the issues of multi-support coordination and dynamic optimization. Summary of the Invention

[0002] To address the technical problems existing in the prior art, this invention proposes an adjustment method based on dynamic priority and multi-support collaborative decoupling, belonging to the field of high-end equipment manufacturing technology. Specifically, to address the problems of low adjustment efficiency and insufficient precision caused by structural complexity and support coupling effects in the machining of asymmetric large marine crankshafts, this invention achieves this through the following technical solution: Step 1: Real-time detection of the gear shift difference (Δ) of each journal. S ) and bounce ( δ ), calculate dynamic priority index , as shown in formula (1);

[0003] In the formula, Δ S δ is the journal runout, which reflects the radial offset of the journal and directly affects the coaxiality of the crankshaft. δ is the circumferential runout, which characterizes the journal's circumferential non-uniformity and affects rotational balance. α and β These are the weighting coefficients for gear shift difference and bounce, respectively, reflecting the importance attached to these two factors.

[0004] Step 2: Set the threshold th Comparison priority index With respect to the threshold size, when ≥ th When a journal is identified as high-risk, it should be adjusted first; the threshold can be dynamically adjusted according to actual process requirements.

[0005] Step 3: Construct the asymmetric stiffness influence matrix The interaction of multiple support regulation is decoupled, as shown in formula (2):

[0006] In the formula, k mn It is the stiffness influence coefficient, representing the support point. m journal n Stiffness contribution, Δ Indicates support point m The adjustment displacement, Δ Journal n The difference in gear shifting.

[0007] Calculate the displacement Δ at each support point 1,Δ 2,Δ 3.

[0008] Step 4: Predict the deformation Δ in the next few seconds based on the sensor measurement signals. S pre The feedforward compensation command is generated as shown in formula (3):

[0009] In the formula, This indicates the predicted shift difference. K p , K d These are the proportional and differential coefficients, Predict the rate of change of gear shift difference.

[0010] Step 5: Perform closed-loop adjustment until the difference in gear shift between each journal is ≤0.01mm and the runout is ≤0.03mm.

[0011] Furthermore, the stiffness matrix The calibration was performed experimentally. The calibration method was as follows: fix other support points and adjust the support individually. m Measure the deformation ΔS of journal n and calculate. =Δ / Δ .

[0012] Furthermore, in predictive compensation control, K p proportionality coefficient and K d The differential coefficients can be adjusted using fuzzy adaptive rules.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects or advantages: This invention proposes an adjustment method based on dynamic priority and multi-support collaborative decoupling, which solves the problems of adjustment lag, coupling interference and low detection efficiency, improves detection accuracy and enhances the robustness of the system. Attached Figure Description

[0014] The present invention will now be described in further detail with reference to the accompanying drawings: Figure 1 This is a flowchart of the adjustment method based on dynamic priority and multi-support collaborative decoupling of the present invention.

[0015] Figure 2 This is a schematic diagram of the measurement of a large ship crankshaft. Detailed Implementation

[0016] Taking a certain type of six-cylinder crankshaft (journal numbers 1#-8#) as an example: 1. Initialization calibration: Calibration of stiffness matrix K Load the prediction model; Set the sensor sampling frequency to 1kHz and the control period to 10ms.

[0017] 2. Real-time adjustment stage: Detected journal #3 Δ =0.008mm, calculate 3 = 0.7 × 0.008 + 0.3 × 0.02 = 0.0116 (Settings) α =0.7, β =0.3), trigger priority adjustment; Decoupling calculation of support displacement Δ 1 = +0.3 mm, Δ 2= 0.2mm; Predicting Δ in the next few seconds =0.004mm, generating feedforward compensation Δ pre =0.0026mm.

[0018] 3. Closed-loop verification: After adjustment, remeasure the Δ of journal #3. =0.003mm, meets the standard.

[0019] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A method for measuring the conditions of large marine crankshafts based on dynamic priority and multi-support collaborative decoupling, characterized in that, Includes the following steps: Step 1: Real-time detection of the gear shift difference (Δ) of each journal. S ) and bounce ( δ ), calculate dynamic priority index , as shown in formula (1); In the formula, Δ S δ is the journal runout, which reflects the radial offset of the journal and directly affects the coaxiality of the crankshaft. δ is the circumferential runout, which characterizes the journal's circumferential non-uniformity and affects rotational balance. α and β These are the weighting coefficients for gear shift difference and bounce, respectively, reflecting the importance attached to these two factors. Step 2: Set the threshold th Comparison priority index With respect to the threshold size, when ≥ th When a journal is identified as high-risk, it should be adjusted first; the threshold can be dynamically adjusted according to actual process requirements. Step 3: Construct the asymmetric stiffness influence matrix The interaction of multiple support regulation is decoupled, as shown in formula (2): In the formula, k mn It is the stiffness influence coefficient, representing the support point. m journal n Stiffness contribution, Δ Indicates support point m The adjustment displacement, Δ journal n The difference in gear shifting. Calculate the displacement Δ at each support point 1,Δ 2,Δ 3. Step 4: Predict the deformation Δ in the next few seconds based on the sensor measurement signals. S pre The feedforward compensation command is generated as shown in formula (3): In the formula, This indicates the predicted shift difference. K p , K d These are the proportional and differential coefficients, Predict the rate of change of gear shift difference. Step 5: Perform closed-loop adjustment until the difference in gear shift between each journal is ≤0.01mm and the runout is ≤0.03mm.

2. The method according to claim 1, characterized in that, In step one, if a certain journal Δ If the value suddenly increases to 150% of the set threshold, the current sequence will be immediately interrupted, and the journal will be adjusted first.

3. The method according to claim 1, characterized in that, The stiffness matrix in step three The calibration was performed experimentally. The calibration method was as follows: fix other support points and adjust the support individually. m Measure journal n Deformation Δ S ,calculate =Δ / Δ .

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