A novel method for generating overload acceleration curves for centrifuges

Abstract

This invention discloses a novel method for generating an overload acceleration curve for a centrifuge, comprising: acquiring the current acceleration 'a' of the centrifuge. i‑1 Set the target acceleration a i acceleration time r i The current acceleration a collected i‑1 and target acceleration a i Convert each to the current rotational speed n i‑1 and target rotational speed n i ; through the current rotational speed n i‑1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max According to the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ; Determine r B If the value is less than 1, a one-segment overload curve is generated; if the value is greater than 1, proceed to step five; based on the time r at the end point B of the first smooth segment of the speed curve. B Obtain the rotational speed n at point B B If n B ≥(n i +n i‑1 If n / 2, then a two-segment overload curve is generated; if n B ≤(n i +n i‑1 If the value is 1 / 2, a three-segment overload curve is generated; the centrifuge operates according to the generated overload curve.

Description

Technical Field

[0001] This invention relates to the field of centrifuges, specifically a novel method for generating overload acceleration curves for centrifuges. Background Technology

[0002] Since the beginning of the 21st century, with the increasing frequency of human activities in the aviation and aerospace fields, and the continuous development of various military equipment, increasingly higher demands have been placed on the performance of aircraft and their airborne components. The performance of equipment is influenced not only by its inherent electronic or mechanical technology but also by the specific operating environment. Harsh environments can lead to a sharp decline in product performance, or even render the product unable to function properly. Among these, steady-state acceleration testing has become one of the key testing items for evaluating the performance of aerospace equipment in various countries. Steady-state acceleration testing can simulate the real overload conditions experienced by the product during flight, and compared to ground-based electrical and mechanical performance assessments, it better reflects the reliability of the equipment and its ability to withstand environmental changes.

[0003] Currently, military industrial units use centrifuges to create overload environments for steady-state acceleration testing of various aerospace equipment. Centrifuge operation mainly includes processes such as start-up, acceleration, stabilization, deceleration, and shutdown, which can be used to simulate the process of various equipment moving from a static state to an overload state and back to a static state. The traditional typical acceleration process of a centrifuge is usually achieved using speed feedback control.

[0004] However, this control method has significant drawbacks when the centrifuge reaches a certain overload value (or speed value) and needs to maintain a steady speed: 1) After accelerating to the target speed, it does not immediately stabilize, but instead produces a large overshoot; 2) After overshoot, multiple oscillations occur, and it may even take a long time for the speed to stabilize; 3) When the speed-up section connects to the steady-speed section, a jump phenomenon will occur, which will impact the equipment.

[0005] The above three points are different from the actual conditions that equipment experiences in the air, and will cause great damage to some precision components and parts. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a novel method for generating overload acceleration curves for centrifuges, comprising: Step 1: Collect the current acceleration a of the centrifuge. i-1 Set the target acceleration a i acceleration time r i ; Step two, collect the current acceleration a i-1 and target acceleration ai Convert each to the current rotational speed n i-1 and target rotational speed n i ; Step 3, using the current rotational speed n i-1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max ; Step 4, based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ; Determine r B If the value is less than 1, a single-stage overload curve is generated; if the value is greater than 1, proceed to step five. Step 5: Based on the time r at the end point B of the first smooth segment of the speed curve. B Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If n / 2, then a two-segment overload curve is generated; if n B <( n i + n i-1 If ) / 2, a three-segment overload curve will be generated; Step six: The centrifuge operates according to the generated overload curve.

[0007] Furthermore, the overload centrifuge speed curve includes: Let the first smooth segment L1 be a quadratic function curve, and let the centrifuge start from the rotational speed. n i-1 Run to speed n B Represented as: Let the second oblique line segment L2 be a linear function, and let the centrifuge speed be... n B Run to speed n D Represented as: Assuming the third smooth segment L3 is a quadratic function curve, the centrifuge speed... n D Run to speed n i Represented as: .

[0008] Furthermore, the aforementioned method using the current rotational speed n i-1 and target rotational speed ni The maximum slope k of the rotational speed curve is obtained. max The following formula is used: .

[0009] Furthermore, the statement based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ,include: The slope of point B is obtained based on the fact that the first smooth segment L1 is a quadratic function curve: Then the time r of B B for: J1 is the adjustment factor.

[0010] Furthermore, the judgment r B If the value is less than 1, then a single-stage overload curve is generated, including: The speed curve is the same as the second sloping segment, starting from the speed n i-1 Run to speed n i The equation for the rotational speed curve is: The corresponding equation for the centrifuge single-stage overload curve is: .

[0011] Furthermore, the time r based on the end point B of the first smooth segment of the rotational speed curve... B Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If ) / 2, a two-segment overload curve is generated, including: The rotational speed n corresponding to point B B =( n i + n i-1 ) / 2, so the actual time at point B is: Therefore, the equation for the first smooth segment is: The equation for the second smooth segment of the rotational speed curve is: Therefore, the equation for the two-stage overload curve is: The corresponding acceleration curve formula is: If n B <( n i + n i-1 If ) / 2, a three-segment overload curve is generated, including: At this point, points B and D do not coincide, and the centrifuge is at r. i Overload a within a time period i-1 Operating to overload a i The slope k at point B B Equal to the maximum slope k of the curve max We can obtain: The equation for the first smooth segment of the rotational speed curve is: The equation for the second smooth segment of the rotational speed curve is: The third smoothing segment L3 is a quadratic function curve, which can be obtained by rotating the first smoothing segment L1 by 180 degrees. The x-coordinate of its maximum point E is the x-coordinate of point D plus r. B ,Right now: Centrifuge from speed n D Run to speed n E The process can be represented as: The equation for the three-stage centrifuge speed curve is as follows: The corresponding three-stage overload curve equation for the centrifuge is: . The beneficial effects of this invention are: the novel centrifuge overload curve generation algorithm is compatible with the general method of calculating typical overload curves, namely, a one-stage overload curve; the S-curve method eliminates the jump situation when connecting the acceleration segment and the steady speed segment; the S-curve method greatly reduces the overshoot when the centrifuge actually runs to the steady speed segment; and the S-curve method can eliminate the oscillation phenomenon after the centrifuge enters the steady speed stage. Attached Figure Description

[0012] Figure 1 A schematic diagram of a novel method for generating overload acceleration curves for centrifuges; Figure 2This is a schematic diagram of the centrifuge speed curve; Figure 3 This is a schematic diagram of the process for generating the overload acceleration curve of a novel centrifuge according to a specific embodiment of the present invention; Figure 4 A schematic diagram of a novel one-stage overload curve for a centrifuge; Figure 5 A schematic diagram of the rotational speed curve of a novel single-stage centrifuge; Figure 6 A schematic diagram of a novel two-stage overload curve for a centrifuge. Figure 7 A schematic diagram of the rotational speed curve of a novel two-stage centrifuge. Figure 8 A schematic diagram of the new three-segment speed curve of a centrifuge; Figure 9 A schematic diagram of the new three-segment speed curve of a centrifuge; Figure 10 A schematic diagram of a typical conventional overload acceleration curve test; Figure 11 Schematic diagram of the new overload acceleration curve test. Detailed Implementation

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the invention, and not all of them. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0016] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0017] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0018] like Figure 1 As shown, a novel method for generating overload acceleration curves for centrifuges includes: Step 1: Collect the current acceleration a of the centrifuge. i-1 Set the target acceleration a i acceleration time r i ; Step two, collect the current acceleration a i-1 and target acceleration a i Convert each to the current rotational speed n i-1 and target rotational speed n i ; Step 3, using the current rotational speed n i-1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max ; Step 4, based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ; Determine r B If the value is less than 1, a single-stage overload curve is generated; if the value is greater than 1, proceed to step five. Step 5: Based on the time r at the end point B of the first smooth segment of the speed curve. B Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If n / 2, then a two-segment overload curve is generated; if n B <( n i + n i-1 If ) / 2, a three-segment overload curve will be generated; Step six: The centrifuge operates according to the generated overload curve.

[0019] The overload centrifuge speed curve includes: Let the first smooth segment L1 be a quadratic function curve, and let the centrifuge start from the rotational speed. n i-1 Run to speed n B Represented as: Let the second oblique line segment L2 be a linear function, and let the centrifuge speed be... n B Run to speed n D Represented as: Assuming the third smooth segment L3 is a quadratic function curve, the centrifuge speed... n D Run to speed n i Represented as: .

[0020] The above refers to the current rotational speed n i-1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max The following formula is used: .

[0021] The above is based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ,include: The slope of point B is obtained based on the fact that the first smooth segment L1 is a quadratic function curve: Then the time r of B B for: J1 is the adjustment factor.

[0022] The judgment r B If the value is less than 1, then a single-stage overload curve is generated, including: The speed curve is the same as the second sloping segment, starting from the speed n i-1 Run to speed n i The equation for the rotational speed curve is: The corresponding equation for the centrifuge single-stage overload curve is: .

[0023] The time r based on the end point B of the first smooth segment of the rotational speed curveB Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If ) / 2, a two-segment overload curve will be generated; The rotational speed n corresponding to point B B =( n i + n i-1 ) / 2, so the actual time at point B is: Therefore, the equation for the first smooth segment is: The equation for the second smooth segment of the rotational speed curve is: Therefore, the equation for the two-stage overload curve is: The corresponding acceleration curve formula is: If n B <( n i + n i-1 If ) / 2, a three-segment overload curve is generated, including: At this point, points B and D do not coincide, and the centrifuge is at r. i Overload a within a time period i-1 Operating to overload a i The slope k at point B B Equal to the maximum slope k of the curve max We can obtain: The equation for the first smooth segment of the rotational speed curve is: The equation for the second smooth segment of the rotational speed curve is: The third smoothing segment L3 is a quadratic function curve, which can be obtained by rotating the first smoothing segment L1 by 180 degrees. The x-coordinate of its maximum point E is the x-coordinate of point D plus r. B ,Right now: Centrifuge from speed n D Run to speed n EThe process can be represented as: The equation for the three-stage centrifuge speed curve is as follows: The corresponding three-stage overload curve equation for the centrifuge is: .

[0024] Specifically, the centrifuge overload starts from a i-1 Run to a i (corresponding speed is) n i ), a i-1 i The acceleration time is r i Then, with acceleration a i Stable t i Time. If we consider a speed-up phase and a steady-speed phase as a step, then a complete speed-up overload curve can be viewed as being composed of multiple steps, such as... Figure 2 As shown.

[0025] Because there is a quadratic relationship between rotational speed and overload, the rotational speed curve of the new centrifuge is designed as an S-shaped curve, and its corresponding overload curve is also designed as an S-shaped curve. The rotational speed curve is designed to consist of three parts: a first smooth segment L1 (a quadratic function curve), a second sloping segment L2 (with slope k). max The first and third smooth segments are defined as L3 (quadratic function curves), and their shapes are set to be identical. They can overlap by rotating 180 degrees. Figure 2 As shown. At the same time, the end point of segment L1 is set as the beginning point of segment L2, and the end point of segment L2 is set as the beginning point of segment L3, so as to ensure that no singular points are generated at the junction of the three segments and to maintain a smooth transition.

[0026] The specific description of this patented method is as follows: Parameter Explanation R The effective radius of the centrifuge g The acceleration due to gravity is 9.8 m / s². 2 , n(t) This is a function representing the rotational speed curve. k max For the speed increase rate, t For time, This is the end time of the previous platform. t i For steady-state operation time, r i For acceleration time, n i -1 The current rotational speed, n i For the target speed,​ a(t) For acceleration curve functions, a i-1 For the current acceleration, a i Accelerate towards the target.

[0027] The equation for the three-segment speed curve is defined as follows: 1) Set the first smooth segment L1 as a quadratic function curve, and the centrifuge speed... n i-1 Run to speed n B The process can be represented as: (1) Let the second oblique line segment L2 be a linear function, and let the centrifuge speed be... n B Run to speed n D The process can be represented as: (2) 3) Set the third smooth segment L3 as a quadratic function curve, and the centrifuge speed... n D Run to speed n i The process can be represented as: (3) Note two cases: ① When both the first smooth segment L1 and the third smooth segment L3 are 0, the speed curve only has the second sloping segment L2. At this time, the three-segment curve degenerates into a one-segment straight line; ② When the second sloping segment is 0, the speed curve is composed of the first smooth segment L1 and the third smooth segment L3. At this time, the three-segment curve degenerates into a two-segment curve.

[0028] Whether the new speed curve is two-segment or three-segment depends on the value n of the final point of the first smooth curve L1. B The size of n. If n B ≥( n i + n i-1 If n ) / 2, then it is a two-part expression; if n B <( n i + n i-1 If the result is 1 / 2, then it becomes a three-segment form. A two-segment form can also be understood as a reduction of a three-segment form (at this point, points B and D coincide).

[0029] Whether the new speed curve is a single segment or a three-segment curve depends on the time r at point B. B If r BIf r < 1, then the first smooth segment is empty (at this time, point B and point A coincide), and the corresponding third smooth segment is also empty (at this time, point D and point E coincide), and the curve will become a single segment; if r B If the value is greater than or equal to 1, then the first smooth segment is not empty, and the corresponding third smooth segment is also not empty, and the curve will become a three-segment curve.

[0030] Since the acceleration time of the entire speed curve is r i Therefore, the maximum slope of the speed curve should not exceed: (4) Taking the derivative of equation (1), we can obtain the slope at point B: (5) Therefore, (6) One-stage speed curve and overload curve At this point, the speed curve is the same as the second sloping segment, directly from the speed n. i-1 Run to speed n i The equation for the rotational speed curve is: (7) The corresponding equation for the centrifuge step-overload curve is: (8) Two-stage speed curve and overload curve At this point, points B and D coincide, and the centrifuge cannot operate at r. i Overload a within a time period i-1 Operating to overload a i Therefore, the actual time from point A to point B cannot be used. r i Instead of using / 2, the solution should be derived from the rotational speed at point B. Since the rotational speed at point B is n... B =( n i + n i-1 ) / 2, the actual time at point B can be calculated as: Therefore, the equation for the first smooth segment is: (10) The equation for the second smooth segment of the rotational speed curve is: (11) Therefore, the equation for the single-step speed curve of the new centrifuge is: (12) The corresponding acceleration curve formula is: (13) Where, k max J1 is the maximum speed increase rate, in rpm / s; J1 is the quadratic coefficient (or adjustment factor).

[0031] Three-segment speed curve and overload curve At this point, points B and D do not coincide, and the centrifuge can operate at r. i Overload a within a time period i-1 Operating to overload a i The slope k at point B B Equal to the maximum slope k of the curve max We can obtain: (14) Therefore, the equation for the first smooth segment of the speed curve is: (15) The second oblique segment L2 of the rotational speed curve is a linear function, which can be expressed as: (16) Substituting the parameters of point B, the final point of the first smooth curve, we can see that: (17) Furthermore, since the starting point of the third smooth segment of the speed curve is the same as the ending point of the second sloping segment, therefore, (18) Therefore, the acceleration time of the second diagonal segment can be obtained: (19) Right now: (20) Therefore, the equation for the second smooth segment of the speed curve is: (twenty one) The third smoothing segment L3 is a quadratic function curve, which can be obtained by rotating the first smoothing segment L1 by 180 degrees. The x-coordinate of its maximum point E is the x-coordinate of point D plus r. B ,Right now: (twenty two) Therefore, the centrifuge's rotational speed n D Run to speed n E The process can be represented as: (twenty three) Therefore, the equation for the single-step speed curve of the new centrifuge is: (twenty four) The corresponding equation for the centrifuge step-overload curve is: (25) In summary, the process for generating the overload acceleration curve of the new centrifuge is as follows: 1 Input parameters (a) i-1 a i r i J1); 2. The current acceleration a i-1 and target acceleration a i Convert to current rotational speed n i-1 and target rotational speed n i ; 3. Calculate the maximum slope k of the rotational speed curve max =(n i -n i-1 ) / r i ; 4. Calculate the time r for point B B ; 5 If r B <1, the three-segment overload curve degenerates into a one-segment overload straight line, and the centrifuge generates the overload curve according to formula (8); 6 If r B ≥1, calculate the rotational speed at point B, the end of the first smooth segment of the rotational speed curve. ; 7 If n B ≥( n i + n i-1 ) / 2, the three-segment S-type overload curve degenerates into a two-segment S-type overload curve, and the centrifuge generates the overload curve according to formula (13); 8 If n B <( n i + n i-1 ) / 2, the centrifuge generates a three-segment S-shaped overload curve according to formula (25); 9. End.

[0032] Experiments were conducted on this centrifuge using both typical conventional overload acceleration curves and novel overload acceleration curves. The two curves were generated by the host computer software, which drove the centrifuge and collected the set and actual overload values ​​in real time, displaying them on the software interface. Figure 10 and Figure 11As shown. By comparing the actual effects of the two methods, it can be seen that the new centrifuge overload acceleration curve provides smoother and more stable control of the centrifuge. The actual overload operating curve can track the desired overload curve better. During dynamic tracking, the actual overload curve shows no overshoot, and during steady-state tracking, the actual overload curve does not oscillate, achieving excellent tracking control results. The implementation method is as follows: 1. Open the main interface of the software and click the "Experimental Parameter Setting" button to enter the sub-interface; 2. Generate a typical traditional overload curve for a centrifuge with three steps (including the acceleration and deceleration sections) using the typical traditional method. 3. Download the typical traditional overload curve of the three-stage step to the lower-level machine; 4. Turn on the auxiliary equipment and check if the system status is normal; 5. Under normal system conditions, click the "Start" button on the main interface, and the centrifuge will operate according to the typical three-stage overload curve. 6. Check the actual operating effect of the centrifuge, compare the set overload and the actual overload to see if they coincide, whether there is overshoot, and whether there is oscillation. 7. Save the data and complete a typical transmission overload test for the centrifuge; 8. Click the "Test Parameter Setting" button again to enter the sub-interface and generate the new four-step overload curve of the centrifuge (including the speed-up and speed-down sections) according to the new method. 9. Download the new four-step overload curve to the lower-level machine; 10. Check if the system status is normal; 11. Under normal system conditions, click the "Start" button on the main interface, and the centrifuge will start running and operate according to the four-step new overload curve law; 12. Check the actual control effect of the centrifuge, compare the set overload and the actual overload to see if they coincide, whether there is overshoot, and whether there is oscillation. 13. Save the data and complete the new type of centrifuge overload test; 14. By comparing the operational effects of the traditional overload curve generation method and the novel overload curve generation method for centrifuges, a conclusion is drawn.

[0033] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A novel method for generating overload acceleration curves for centrifuges, characterized in that, include: Step 1: Collect the current acceleration a of the centrifuge. i-1 Set the target acceleration a i acceleration time r i ; Step two, collect the current acceleration a i-1 and target acceleration a i Convert each to the current rotational speed n i-1 and target rotational speed n i ; Step 3, using the current rotational speed n i-1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max ; Step 4, based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ; Determine r B If the value is less than 1, a single-stage overload curve is generated; if the value is greater than 1, proceed to step five. Step 5: Based on the time r at the end point B of the first smooth segment of the speed curve. B Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If n / 2, then a two-segment overload curve is generated; if n B <( n i + n i-1 If ) / 2, a three-segment overload curve will be generated; Step six: The centrifuge operates according to the generated overload curve; The overload centrifuge speed curve includes: Let the first smooth segment L1 be a quadratic function curve, and let the centrifuge start from the rotational speed. n i-1 Run to speed n B Represented as: ； Let the second oblique line segment L2 be a linear function, and let the centrifuge speed be... n B Run to speed n D Represented as: ； Assuming the third smooth segment L3 is a quadratic function curve, the centrifuge speed... n D Run to speed n i Represented as: ； The above refers to the current rotational speed n i-1 and target rotational speed n i The maximum slope k of the rotational speed curve is obtained. max The following formula is used: ； The above is based on the maximum slope k max The time r for obtaining the end point B of the first smooth segment of the speed curve B ,include: The slope of point B is obtained based on the fact that the first smooth segment L1 is a quadratic function curve: ； Then the time r at point B B for: ； J1 is the adjustment factor; The judgment r B If the value is less than 1, then a single-stage overload curve is generated, including: The speed curve is the same as the second sloping segment, starting from the speed n i-1 Run to speed n i The equation for the rotational speed curve is: ； The corresponding equation for the centrifuge single-stage overload curve is: 。 2. The novel method for generating an overload acceleration curve for a centrifuge according to claim 1, characterized in that, The time r based on the end point B of the first smooth segment of the rotational speed curve B Obtain the rotational speed n at point B B If n B ≥( n i + n i-1 If ) / 2, then a two-segment overload curve is generated. include: The rotational speed n corresponding to point B B =( n i + n i-1 ) / 2, so the actual time at point B is: Therefore, the equation for the first smooth segment is: The equation for the second smooth segment of the rotational speed curve is: Therefore, the equation for the two-stage overload curve is: The corresponding acceleration curve formula is: If n B <( n i + n i-1 If ) / 2, a three-segment overload curve is generated, including: At this point, points B and D do not coincide, and the centrifuge is at r. i Overload a within a time period i-1 Operation to overload a i The slope k at point B B Equal to the maximum slope k of the curve max We can obtain: The equation for the first smooth segment of the rotational speed curve is: The equation for the second smooth segment of the rotational speed curve is: The third smoothing segment L3 is a quadratic function curve, which can be obtained by rotating the first smoothing segment L1 by 180 degrees. The x-coordinate of its maximum point E is the x-coordinate of point D plus r. B ,Right now: Centrifuge from speed n D Run to speed n E The process can be represented as: The equation for the three-stage centrifuge speed curve is as follows: ； The corresponding three-stage overload curve equation for the centrifuge is: 。

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