Automatic polishing control method, device and system for aluminum alloy die castings

Abstract

The present invention relates to the technical field of automatic control devices for a series of single steps when grinding a workpiece, and specifically to an automatic polishing control method, device and system applied to aluminum alloy die castings, including: obtaining the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment, determining the difference of the vibration data at each moment, and then determining the degree of influence of the historical stage at the current moment, thereby determining the abnormality of the vibration data at the current moment, thereby obtaining the reference adjustment coefficient at the current moment, which is used as the input of a PID controller and outputs a control instruction. The present invention determines the reference adjustment coefficient by analyzing the vibration of the aluminum alloy die casting during the automatic polishing process to improve the effect of polishing control.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control devices for a series of individual steps in grinding a workpiece, and in particular to an automatic polishing control method, device and system for aluminum alloy die castings. Background Art

[0002] When aluminum alloy die castings are processed, the molten aluminum alloy is quickly injected into the mold under high pressure, and the aluminum alloy is cooled and solidified in the mold to form the desired shape. During the die casting process, the surface of the product will be rough due to bubbles or impurities in the casting process. When the product is used in the subsequent process, the minor defects that may be generated during the die casting process, such as small pits and scratches, can be removed by polishing. At the same time, polishing can further improve the dimensional accuracy and surface roughness of the die casting to meet higher requirements.

[0003] Existing problem: When the same type of aluminum alloy die-castings are polished using automated polishing equipment with preset polishing parameters, the preset fixed polishing parameters may result in poor polishing control of some aluminum alloy die-castings because the surfaces of the same type of aluminum alloy die-castings from different production batches may have different degrees of roughness. Summary of the invention

[0004] The invention provides an automatic polishing control method, device and system applied to aluminum alloy die castings to solve the existing problems.

[0005] The automatic polishing control method, device and system for aluminum alloy die castings of the present invention adopt the following technical solutions:

[0006] An embodiment of the present invention provides an automatic polishing control method for aluminum alloy die castings, the method comprising the following steps:

[0007] Obtain the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment;

[0008] According to the polishing position coordinates at each moment, each stage is divided into a plurality of cycles; according to the difference between the vibration data at each moment in adjacent cycles in the same stage, the difference of the vibration data at each moment is determined;

[0009] According to the similarity between the vibration data of different aluminum alloy die castings during the polishing process, the influence degree of the historical stage at the current moment is determined;

[0010] Determining the abnormality of the vibration data at the current moment according to the degree of influence of the historical stage at the current moment and the difference of the vibration data at the current moment;

[0011] According to the abnormal situation of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates in the same cycle of the same stage of the polishing process of all aluminum alloy die castings, the reference adjustment coefficient at the current moment is determined; the reference adjustment coefficient at the current moment is used as the input of the PID controller to output a control instruction.

[0012] Furthermore, each stage is divided into several cycles, including the following specific steps:

[0013] In each stage of the polishing process of each aluminum alloy die casting, the polishing position coordinates at the first moment are used as the target polishing position coordinates, and the moment when the polishing position coordinates are the same as the target polishing position coordinates is recorded as the splitting moment, and the stage is divided into several cycles using the splitting moment.

[0014] Furthermore, the determination of the difference of the vibration data at each moment includes the following specific steps:

[0015] In each cycle of each stage during the polishing process of each aluminum alloy die casting, the difference between the vibration data at the jth moment and the vibration data at the j-1th moment is taken as the slope at the jth moment;

[0016] The stage at the tth moment during the polishing process of the i-th aluminum alloy die casting is recorded as the target stage;

[0017] In the target phase, the period before the period at the t-th moment is recorded as the target period;

[0018] In each target cycle, the moment when the polishing position coordinates are the same as the polishing position coordinates at the tth moment is recorded as the reference moment;

[0019] The difference of the vibration data at the tth moment is determined according to the slope and the vibration data at the tth moment and the reference moment.

[0020] Furthermore, the determining of the difference of the vibration data at the time t includes the following specific steps:

[0021] Calculate the inversely proportional normalized value of the absolute value of the difference between the slope at the t-th moment and the x-th reference moment as the first absolute value of the difference, and calculate the absolute value of the difference between the vibration data at the t-th moment and the x-th reference moment as the second absolute value of the difference;

[0022] Taking the product of the absolute value of the second difference and the absolute value of the first difference as the first product at the x-th reference moment;

[0023] The sum of the first products of all reference moments is taken as the difference of the vibration data at the t-th moment.

[0024] Furthermore, the determination of the historical stage impact degree at the current moment includes the following specific steps:

[0025] A time threshold m is preset, and in each stage of the polishing process of each aluminum alloy die casting, a time period from the nmth moment to the nth moment is used as the target time period at the nth moment, and the vibration data of all moments within the target time period at the nth moment are used to form the vibration data vector at the nth moment;

[0026] The aluminum alloy die castings include: current aluminum alloy die castings and historical aluminum alloy die castings;

[0027] The polishing position coordinates at the zth moment in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting are used as the main body polishing position coordinates;

[0028] In the first cycle of the yth stage of the polishing process of each historical aluminum alloy die casting, the moment when the polishing position coordinates are the same as the main body polishing position coordinates is recorded as the main body moment;

[0029] Calculate the cosine similarity between the vibration data vector at the zth moment and the vibration data vector at each main moment, calculate the mean value B1 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, calculate the standard deviation B2 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, and use B1-B2 as the similarity threshold;

[0030] Among the cosine similarities between the vibration data vector at the zth moment and the vibration data vectors at all main moments, the cosine similarity greater than the similarity threshold is used as the target cosine similarity; the average of all target cosine similarities is used as the fluctuation situation at the zth moment;

[0031] According to the fluctuation conditions at each moment in each cycle of each stage of the polishing process of the current aluminum alloy die casting, the influence degree of the historical stage at the current moment is determined.

[0032] Furthermore, the process of determining the historical stage influence degree at the current moment according to the fluctuation situation at each moment in each cycle of each stage of the polishing process of the current aluminum alloy die casting comprises the following specific steps:

[0033] The average of the fluctuation conditions at all moments in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting is used as the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting;

[0034] According to the method for obtaining the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting, the fluctuation condition of the last cycle of the yth stage of the polishing process of the current aluminum alloy die casting is obtained;

[0035] The stage at which the current aluminum alloy die casting is in the polishing process at the current moment is recorded as the pth stage; wherein p is a positive integer;

[0036] When p=1, the historical stage influence degree at the current moment is set to the preset first constant;

[0037] When p>1, during the polishing process of the current aluminum alloy die-casting, the ratio of the fluctuation situation in the first cycle of the p-th stage to the fluctuation situation in the last cycle of the p-1-th stage is calculated as the first ratio, the inversely proportional normalized value of the absolute value of the difference between the fluctuation situation in the first cycle of the p-1-th stage and the fluctuation situation in the last cycle of the p-1-th stage is calculated as the fluctuation difference of the p-1-th stage, and in all stages before the p-th stage, the sum of the fluctuation differences of all stages is taken as the fluctuation adjustment coefficient, and the sum of the normalized value of the product of the fluctuation adjustment coefficient and the first ratio and the preset first constant is taken as the degree of influence of the historical stage at the current moment.

[0038] Furthermore, the determining of the abnormality of the vibration data at the current moment includes the following specific steps:

[0039] The normalized value of the product of the historical stage influence degree at the current moment and the difference of the vibration data at the current moment is used as the abnormality of the vibration data at the current moment.

[0040] Furthermore, the determination of the reference adjustment coefficient at the current moment includes the following specific steps:

[0041] If the abnormality of the vibration data at the current moment is less than or equal to the preset judgment threshold, the reference adjustment coefficient at the current moment is set to the preset second constant;

[0042] If the abnormality of the vibration data at the current moment is greater than the preset judgment threshold, in the cycle of each stage of the polishing process of the historical aluminum alloy die casting that is the same as the cycle of the stage at the current moment, the vibration data at the moment when the polishing position coordinates are the same as the polishing position coordinates at the current moment is recorded as the target vibration data;

[0043] The mean of all target vibration data is calculated as a first mean, and a normalized value of a difference between the first mean and the vibration data at the current moment is taken as a reference adjustment coefficient at the current moment.

[0044] The present invention also proposes an automatic polishing control device for aluminum alloy die castings, which adopts the automatic polishing control method for aluminum alloy die castings. The device includes the following modules:

[0045] Data acquisition module: used to obtain the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment;

[0046] Cycle analysis module: used to divide each stage into several cycles according to the polishing position coordinates at each moment; determine the difference of vibration data at each moment according to the difference between vibration data at each moment in adjacent cycles in the same stage;

[0047] Stage analysis module: used to determine the degree of historical stage influence at the current moment based on the similarity between the vibration data of different aluminum alloy die castings during the polishing process;

[0048] Abnormal analysis module: used to determine the abnormality of the vibration data at the current moment according to the influence degree of the historical stage at the current moment and the difference of the vibration data at the current moment;

[0049] Instruction control module: used to determine the reference adjustment coefficient at the current moment according to the abnormal situation of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates at the same stage and the same cycle of the polishing process of all aluminum alloy die-castings at the corresponding moment; use the reference adjustment coefficient at the current moment as the input of the PID controller and output the control instruction.

[0050] The present invention also proposes an automatic polishing control system for aluminum alloy die castings, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program stored in the memory to implement the steps of the aforementioned automatic polishing control method for aluminum alloy die castings.

[0051] The beneficial effects of the technical solution of the present invention are:

[0052] In an embodiment of the present invention, the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process are obtained, and the difference of the vibration data at each moment is determined. By analyzing the difference of vibration data between different cycles of the same stage, the change of repeated polishing in the same stage is reflected, which is used as the basic parameter of the subsequent reference adjustment coefficient to ensure the accuracy of the control instruction. Then determine the influence degree of the historical stage at the current moment, and by analyzing the difference of vibration data between adjacent stages, the progressive change of polishing in adjacent stages is reflected, which is used as the basic parameter of the subsequent reference adjustment coefficient to further ensure the accuracy of the control instruction. In this way, the reference adjustment coefficient at the current moment is obtained, which is used as the input of the PID controller, and the control instruction is output, that is, accurate adaptive polishing parameters are obtained. So far, the present invention determines the reference adjustment coefficient by analyzing the vibration of the aluminum alloy die casting during the automatic polishing process to improve the effect of polishing control. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 It is a flow chart of the steps of the automatic polishing control method applied to aluminum alloy die castings of the present invention;

[0055] Figure 2 This is a module structure diagram of the automatic polishing control device applied to aluminum alloy die castings of the present invention;

[0056] Figure 3 Schematic diagram of aluminum alloy die casting. DETAILED DESCRIPTION

[0057] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the automatic polishing control method, device and system for aluminum alloy die castings proposed by the present invention, its specific implementation method, structure, features and effects in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0058] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0059] The specific scheme of the automatic polishing control method, device and system for aluminum alloy die castings provided by the present invention is described in detail below with reference to the accompanying drawings.

[0060] See also Figure 1 , which shows a flowchart of the steps of an automatic polishing control method for aluminum alloy die castings provided by an embodiment of the present invention, the method comprising the following steps:

[0061] Step S001: Obtaining the polishing position coordinates and vibration data of each aluminum alloy die casting at each moment in each stage of the polishing process.

[0062] For several aluminum alloy die castings of the same type, the vibration data and polishing position coordinates of each aluminum alloy die casting at each stage of the polishing process are collected in turn. Among them, the current aluminum alloy die casting is the one that is being polished, and the historical aluminum alloy die casting has been polished.

[0063] It should be noted that the polishing process is generally divided into rough polishing, medium polishing, fine polishing and fine polishing stages. The vibration sensor is installed at the key part (polishing head) of the polishing equipment to collect vibration data. The three-dimensional coordinates are constructed with the length, width and height of the aluminum alloy die-casting to obtain the three-dimensional coordinates of each point on the surface of the aluminum alloy die-casting. The three-dimensional coordinates of the center of the contact surface between the polishing head and the surface of the aluminum alloy die-casting at each moment are used as the polishing position coordinates.

[0064] It should be further explained that: in each polishing stage of this embodiment, a polishing head is used to repeatedly polish the surface of the aluminum alloy die-casting. The polishing head starts from a set starting point on the surface of the aluminum alloy die-casting and polishes the entire surface of the aluminum alloy die-casting without repetition along the set moving trajectory until it returns to the starting point, that is, the starting point in the set moving trajectory is also the end point, and then repeats this operation until the polishing requirements of this polishing stage are met, and then the polishing is stopped to complete the polishing of this stage, and then the polishing parameters of the polishing equipment are adjusted and the abrasive is replaced to perform the next stage of polishing. The moving trajectory of the polishing head set in each stage is the same, that is, only the polishing parameters and abrasives are different in different stages. The polishing parameters include: polishing speed, pressure, rotation speed of the polishing head and feed speed, which are collected by the integrated sensor on the polishing equipment. Among them, the schematic diagram of the aluminum alloy die-casting, such as Figure 3 shown.

[0065] Step S002: Divide each stage into a number of cycles according to the polishing position coordinates at each moment; determine the difference of the vibration data at each moment according to the difference between the vibration data at each moment in adjacent cycles in the same stage.

[0066] Since vibration data provides information about the vibration levels generated during the polishing process. When the polishing pressure is too high or uneven, it may cause vibrations on the surface of the aluminum alloy die casting, which can be detected by the vibration sensor. An increase in vibration levels usually indicates an increase in friction between the polishing head and the aluminum alloy die casting, which may be caused by excessive polishing pressure or uneven contact area between the polishing head and the aluminum alloy die casting. By monitoring the vibration data, the pressure distribution during the polishing process can be indirectly understood. If abnormal vibration levels are detected, this may mean that the polishing parameters need to be adjusted to avoid excessive wear or damage to the aluminum alloy die casting.

[0067] During the grinding and polishing of aluminum alloy die castings, it can be seen that the reason for the generation of vibration data is due to the roughness of the surface of the aluminum alloy die castings and the shape of the aluminum alloy die castings themselves. Therefore, the obtained vibration data is related to the position during grinding. At the same time, when grinding aluminum alloy die castings, the entire surface of the aluminum alloy die castings will be repeatedly polished. According to the obtained grinding operation conditions, it is divided into cycles. One cycle is a complete grinding process of traversing the surface of the aluminum alloy die casting. It can be seen that when dividing the cycle, it is through the reciprocating position, rather than by a fixed time.

[0068] Preferably, in one embodiment of the present invention, the method for obtaining the difference of vibration data at each moment includes:

[0069] In each stage of the polishing process of each aluminum alloy die casting, the polishing position coordinates at the first moment are used as the target polishing position coordinates, and the moment when the polishing position coordinates are the same as the target polishing position coordinates is recorded as the split moment. All split moments are used to divide the stage into several cycles.

[0070] It should be noted that each cycle is a period of time in each stage during which the polishing head traverses the entire surface of the aluminum alloy die casting without repetition, that is, the polishing position coordinates at all times in each cycle are different.

[0071] Since the entire data is a whole when grinding and polishing, the data of different stages will affect the data of the next stage, and the grinding conditions of the previous cycle of the same stage will also have an impact on the grinding conditions of the next cycle. For example, in the rough polishing stage, harder abrasives and greater pressure may be used to quickly remove material, and the vibration data at this time usually shows a higher vibration level. If too much vibration is generated in this stage, it may cause scratches or uneven material removal on the surface of the workpiece, which will affect the processing quality in the fine polishing stage. When entering the fine polishing stage, softer abrasives and less pressure are usually used to refine the surface, and the vibration data at this time should show a lower vibration level. If the vibration in the rough polishing stage is too large, it may take more time and effort to correct surface defects in the fine polishing stage, which will cause the vibration data in the fine polishing stage to be affected.

[0072] In the case of repeated polishing, the polishing effect is determined by the similarity between adjacent cycles in the same stage. For example, when the vibration data of the g-th cycle and the vibration data of the g-1th cycle are similar in amplitude, it means that the polishing efficiency of the acquired data is not high at this time, and the vibration is the fluctuation caused by normal contact during polishing. The polishing at the current stage may have been smoothed, and the next stage of polishing can be carried out.

[0073] In each cycle of each stage in the polishing process of each aluminum alloy die casting, the difference between the vibration data at the jth moment and the vibration data at the j-1th moment is taken as the slope at the jth moment.

[0074] It should be noted that the slope at the second moment in each cycle is taken as the slope at the first moment.

[0075] Taking the tth moment in the polishing process of the i-th aluminum alloy die casting as an example, the stage at the tth moment is recorded as the target stage. In the target stage, the cycle before the cycle at the tth moment (excluding the cycle at the tth moment) is recorded as the target cycle.

[0076] It should be noted that in this embodiment, the first cycle of each stage is not controlled and adjusted. This is because each stage of the polishing process involves repeated grinding. Therefore, the data of the first cycle of each stage is used as the basic data for the grinding control and adjustment of subsequent cycles.

[0077] In each target cycle, the moment when the polishing position coordinates are the same as the polishing position coordinates at the tth moment is recorded as the reference moment, thereby obtaining the reference moment in each target cycle.

[0078] Calculate the inversely proportional normalized value of the absolute value of the difference in slope between the t-th moment and the x-th reference moment as the first absolute value of the difference, calculate the absolute value of the difference in vibration data between the t-th moment and the x-th reference moment as the second absolute value of the difference, take the product of the second absolute value of the difference and the first absolute value of the difference as the first product of the x-th reference moment, and take the sum of the first products of all reference moments as the difference in vibration data at the t-th moment.

[0079] It should be noted that the absolute value of the difference between the slope at the t-th moment and the x-th reference moment is recorded as A. In this embodiment, exp(-A) is used to present the inverse proportional relationship and normalization processing of A. The implementer can set the inverse proportional function and normalization function according to the actual situation. exp() is an exponential function with a natural constant as the base. The smaller A is, the similar vibration change trend of the same polishing position coordinate in the same stage in different cycles is. At this time, the larger the absolute value of the second difference is, the more abnormal the vibration data at the t-th moment is, and the more regulation is needed.

[0080] According to the above method, the difference of vibration data at each moment during the polishing process of each aluminum alloy die casting is obtained.

[0081] Step S003: Determine the degree of influence of the historical stage at the current moment according to the similarity between the vibration data of different aluminum alloy die castings during the polishing process.

[0082] Thus, the comparative analysis between different cycles in the same stage is completed. Further comparative analysis is required based on the vibration data of the current aluminum alloy die casting and the historical aluminum alloy die casting during the polishing process. It is known that the entire data is a whole during polishing, and the data of different stages will affect the data of the next stage. Only by analyzing the deviation of vibration data through different cycles in the same stage, it is easy to cause the normal vibration data to be classified as abnormal, resulting in unnecessary equipment parameter adjustments.

[0083] In this way, the vibration data of the last cycle in each stage and the vibration cycle data at the beginning of the next stage can be obtained. At the connection between the two stages, the influence of the vibration data in the previous stage on the next stage can be analyzed.

[0084] Preferably, in one embodiment of the present invention, the method for obtaining the historical stage influence degree at the current moment includes:

[0085] The preset time threshold m is 5, which is taken as an example for description.

[0086] In each stage of the polishing process of each aluminum alloy die casting, the time period from the nmth moment to the nth moment is taken as the target time period of the nth moment, and the vibration data of all moments within the target time period of the nth moment constitute the vibration data vector of the nth moment.

[0087] According to the above method, the target time period at each moment in each stage of the polishing process of each aluminum alloy die casting is obtained. In this embodiment, the target time period is not obtained for the first m moments of each stage.

[0088] The polishing position coordinates at the zth moment in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting are used as the main body polishing position coordinates.

[0089] In the first cycle of the yth stage of the polishing process of each historical aluminum alloy die casting, the moment when the polishing position coordinates are the same as the main body polishing position coordinates is recorded as the main body moment, thereby obtaining the main body moment corresponding to each historical aluminum alloy die casting.

[0090] Calculate the cosine similarity between the vibration data vector at the zth moment and the vibration data vector at each main moment, calculate the mean B1 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, calculate the standard deviation B2 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, and use B1-B2 as the similarity threshold.

[0091] Among the cosine similarities between the vibration data vector at the zth moment and the vibration data vectors at all subject moments, the cosine similarity greater than the similarity threshold is used as the target cosine similarity, and the average of all target cosine similarities is used as the fluctuation at the zth moment.

[0092] It should be noted that the calculation of the cosine similarity between two data vectors is a well-known technique, and the specific method is not introduced here. The value range of the cosine similarity is -1 to 1, where -1 indicates that the two vectors are completely dissimilar, and 1 indicates that the two vectors are completely similar. The target cosine similarity greater than the similarity threshold is selected to avoid interference from special vibration data during the polishing process of historical aluminum alloy die castings, such as the surface of historical aluminum alloy die castings being too rough.

[0093] According to the method for obtaining the fluctuation condition at the zth moment, the fluctuation condition at each moment in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting is obtained.

[0094] The average of the fluctuation conditions at all moments in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting is taken as the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting.

[0095] According to the method of obtaining the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting, the fluctuation condition of the last cycle of the yth stage of the polishing process of the current aluminum alloy die casting is obtained.

[0096] According to the above method, the fluctuation conditions of the first and last cycles of each stage of the polishing process of the current aluminum alloy die casting are obtained.

[0097] The first constant c is preset to be 1, and the second constant is preset to be 0, and this is used as an example for description.

[0098] The stage of the polishing process of the current aluminum alloy die casting at the current moment is recorded as the pth stage, where p is a positive integer.

[0099] When p=1, there is no previous stage. In this embodiment, the historical stage influence degree at the current moment is set to the preset first constant c.

[0100] When p>1, in the polishing process of the current aluminum alloy die-casting, the ratio of the fluctuation situation in the first cycle of the p-th stage to the fluctuation situation in the last cycle of the p-1-th stage is calculated as the first ratio, and the inversely proportional normalized value of the absolute value of the difference between the fluctuation situation in the first cycle of the p-1-th stage and the fluctuation situation in the last cycle of the p-1-th stage is calculated as the fluctuation difference of the p-1-th stage. In all stages before the p-th stage (excluding the p-th stage), the sum of the fluctuation differences of all stages is taken as the fluctuation adjustment coefficient, and the sum of the normalized value of the product of the fluctuation adjustment coefficient and the first ratio and the preset first constant c is taken as the degree of influence of the historical stage at the current moment.

[0101] It should be noted that: the absolute value of the difference between the fluctuation of the first cycle of the pth stage and the fluctuation of the last cycle of the p-1th stage is recorded as D. In this embodiment, exp(-D) is used to present the inverse proportional relationship and normalization of D. The product of the fluctuation adjustment coefficient and the first ratio is recorded as R. In this embodiment, norm(R) is used as the normalized value of R, wherein norm() is a linear normalization function used to normalize the data value to between 0 and 1. When the first ratio is large, it means that the current stage has a larger fluctuation compared with the previous stage, and the greater the impact of the previous stage on the current stage, the smaller the fluctuation adjustment coefficient is at this time, indicating that there is a larger fluctuation change between the first and last cycles in each stage before the pth stage, and it means that only the current stage has a larger fluctuation compared with the previous stage, so the degree of influence of the historical stage at the current moment is greater.

[0102] It should be further explained that: in this embodiment, the first cycle of each stage is not controlled and adjusted, so the above calculation is performed only when the current stage is in the second cycle or above, so there must be fluctuations in the first cycle of the pth stage.

[0103] Step S004: determining the abnormality of the vibration data at the current moment according to the influence degree of the historical stage at the current moment and the difference of the vibration data at the current moment.

[0104] Preferably, in one embodiment of the present invention, the method for obtaining the abnormal situation of the vibration data at the current moment includes:

[0105] The normalized value of the product of the difference of the vibration data at the current moment and the influence degree of the historical stage at the current moment is taken as the abnormality of the vibration data at the current moment.

[0106] It should be noted that the product of the difference in vibration data at the current moment and the degree of influence of the historical stage at the current moment is recorded as F. In this embodiment, norm(F) is used as the normalized value of F. The greater the difference in vibration data at the moment, the greater the difference in vibration at the same position in different cycles in the same stage, and similar stable polishing should be performed in each cycle in the same stage, that is, the vibration data between different cycles should be similar, so the more adjustment is needed at the current moment, and the greater the degree of influence of the historical stage at the current moment, the greater the difference in fluctuation between the current stage and the previous stage in the same polishing process, so the more adjustment is needed at the current moment.

[0107] Step S005: Determine the reference adjustment coefficient at the current moment according to the abnormal situation of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates in the same cycle of the same stage of the polishing process of all aluminum alloy die-castings; use the reference adjustment coefficient at the current moment as the input of the PID controller and output a control instruction.

[0108] Preferably, in one embodiment of the present invention, the method for obtaining the reference adjustment coefficient at the current moment includes:

[0109] The preset judgment threshold is 0.68, and this is used as an example for description.

[0110] If the abnormality of the vibration data at the current moment is less than or equal to the preset judgment threshold, it means that the vibration data at the current moment is normal, and the reference adjustment coefficient at the current moment is set to the preset second constant 0.

[0111] If the abnormality of the vibration data at the current moment is greater than the preset judgment threshold, it is necessary to determine the reference adjustment coefficient based on the vibration data of the polishing process of the historical aluminum alloy die casting.

[0112] In the cycle of each stage of the polishing process of the historical aluminum alloy die casting that is the same as the cycle of the stage at the current moment, the vibration data at the moment when the polishing position coordinates are the same as the polishing position coordinates at the current moment is recorded as the target vibration data. Thus, the target vibration data corresponding to each historical aluminum alloy die casting is obtained.

[0113] The mean of all target vibration data is calculated as the first mean, and a normalized value of the difference between the first mean and the vibration data at the current moment is taken as the reference adjustment coefficient at the current moment.

[0114] It should be noted that: in this embodiment, the difference between the first mean and the vibration data at the current moment is normalized to between -1 and 1 using a hyperbolic tangent function, which is a known technique. If the vibration data at the current moment is larger than the first mean, it means that the friction between the current polishing head and the surface of the aluminum alloy die casting is large, and the pressure needs to be reduced at this time, that is, the reference adjustment coefficient is biased towards -1; if the vibration data at the current moment is smaller than the first mean, it means that the friction between the current polishing head and the surface of the aluminum alloy die casting is small, and the pressure needs to be increased at this time, that is, the reference adjustment coefficient is biased towards 1.

[0115] Therefore, the reference adjustment coefficient, vibration data, polishing speed, pressure, rotation speed and feed speed of the polishing equipment at the current moment are input into the PID controller to output a control instruction. The control instruction is the value of each polishing parameter at the next moment of the current moment. The PID controller is a well-known technology and will not be described in detail here. The automatic polishing control of aluminum alloy die castings is now completed.

[0116] It should be noted that if the data collected at the current moment is directly used for PID control, the different cycles in the same stage, that is, the change characteristics of the vibration data during the repeated polishing process in the same stage, and the gradual progressive characteristics of the polishing effect between different stages will be ignored, which may easily cause large errors in the output control instructions. Therefore, this embodiment obtains accurate adaptive polishing parameters by analyzing the reference adjustment coefficient, thereby improving the polishing effect.

[0117] Second, see Figure 2 , which shows an automatic polishing control device for aluminum alloy die castings provided by one embodiment of the present invention, the device includes the following modules:

[0118] Data acquisition module: used to obtain the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment;

[0119] Cycle analysis module: used to divide each stage into several cycles according to the polishing position coordinates at each moment; determine the difference of vibration data at each moment according to the difference between vibration data at each moment in adjacent cycles in the same stage;

[0120] Stage analysis module: used to determine the degree of historical stage influence at the current moment based on the similarity between the vibration data of different aluminum alloy die castings during the polishing process;

[0121] Abnormal analysis module: used to determine the abnormality of the vibration data at the current moment according to the influence degree of the historical stage at the current moment and the difference of the vibration data at the current moment;

[0122] Instruction control module: used to determine the reference adjustment coefficient at the current moment according to the abnormal situation of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates at the same stage and the same cycle of the polishing process of all aluminum alloy die-castings at the corresponding moment; use the reference adjustment coefficient at the current moment as the input of the PID controller and output the control instruction.

[0123] In a third aspect, the present invention also provides an automatic polishing control system for aluminum alloy die castings, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program stored in the memory to implement the steps of the aforementioned automatic polishing control method for aluminum alloy die castings.

[0124] So far, the present invention is completed.

[0125] In summary, in the embodiment of the present invention, the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment are obtained, the difference of the vibration data at each moment is determined, and then the influence degree of the historical stage at the current moment is determined, thereby determining the abnormality of the vibration data at the current moment, and thereby obtaining the reference adjustment coefficient at the current moment, which is used as the input of the PID controller and outputs the control instruction. The present invention determines the reference adjustment coefficient by analyzing the vibration of the aluminum alloy die casting during the automatic polishing process to improve the effect of polishing control.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic polishing control method for aluminum alloy die castings, characterized in that: The method comprises the following steps: Obtain the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment; According to the polishing position coordinates at each moment, each stage is divided into a plurality of cycles; according to the difference between the vibration data at each moment in adjacent cycles in the same stage, the difference of the vibration data at each moment is determined; According to the similarity between the vibration data of different aluminum alloy die castings during the polishing process, the influence degree of the historical stage at the current moment is determined; Determining the abnormality of the vibration data at the current moment according to the degree of influence of the historical stage at the current moment and the difference of the vibration data at the current moment; Determine a reference adjustment coefficient at the current moment according to the abnormality of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates at the same stage and the same cycle of the polishing process of all aluminum alloy die castings at the corresponding moment; use the reference adjustment coefficient at the current moment as the input of the PID controller and output a control instruction; Each stage is divided into several cycles, and the specific steps included are as follows: In each stage of the polishing process of each aluminum alloy die casting, the polishing position coordinates at the first moment are used as the target polishing position coordinates, and the moment when the polishing position coordinates are the same as the target polishing position coordinates is recorded as the splitting moment, and the stage is divided into several cycles using the splitting moment.

2. The automatic polishing control method for aluminum alloy die castings according to claim 1 is characterized in that: The specific steps of determining the difference of vibration data at each moment are as follows: In each cycle of each stage during the polishing process of each aluminum alloy die casting, the difference between the vibration data at the jth moment and the vibration data at the j-1th moment is taken as the slope at the jth moment; The stage at the tth moment during the polishing process of the i-th aluminum alloy die casting is recorded as the target stage; In the target phase, the period before the period at the t-th moment is recorded as the target period; In each target cycle, the moment when the polishing position coordinates are the same as the polishing position coordinates at the tth moment is recorded as the reference moment; The difference of the vibration data at the tth moment is determined according to the slope and the vibration data at the tth moment and the reference moment.

3. The automatic polishing control method for aluminum alloy die castings according to claim 2 is characterized in that: The determining of the difference of the vibration data at the time t includes the following specific steps: Calculate an inversely proportional normalized value of the absolute value of the difference between the slope at the t-th moment and the x-th reference moment as the first absolute value of the difference, and calculate the absolute value of the difference between the vibration data at the t-th moment and the x-th reference moment as the second absolute value of the difference; Taking the product of the absolute value of the second difference and the absolute value of the first difference as the first product at the x-th reference moment; The sum of the first products of all reference moments is taken as the difference of the vibration data at the t-th moment.

4. The automatic polishing control method for aluminum alloy die castings according to claim 1 is characterized in that: The specific steps of determining the impact degree of the historical stage at the current moment are as follows: A time threshold m is preset, and in each stage of the polishing process of each aluminum alloy die casting, a time period from the nmth moment to the nth moment is used as the target time period at the nth moment, and the vibration data of all moments within the target time period at the nth moment are used to form the vibration data vector at the nth moment; The aluminum alloy die castings include: current aluminum alloy die castings and historical aluminum alloy die castings; The polishing position coordinates at the zth moment in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting are used as the main body polishing position coordinates; In the first cycle of the yth stage of the polishing process of each historical aluminum alloy die casting, the moment when the polishing position coordinates are the same as the main body polishing position coordinates is recorded as the main body moment; Calculate the cosine similarity between the vibration data vector at the zth moment and the vibration data vector at each main moment, calculate the mean value B1 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, calculate the standard deviation B2 of the cosine similarity between the vibration data vector at the zth moment and the vibration data vectors at all main moments, and use B1-B2 as the similarity threshold; Among the cosine similarities between the vibration data vector at the zth moment and the vibration data vectors at all main moments, the cosine similarity greater than the similarity threshold is used as the target cosine similarity; the average of all target cosine similarities is used as the fluctuation situation at the zth moment; According to the fluctuation conditions at each moment in each cycle of each stage of the polishing process of the current aluminum alloy die casting, the influence degree of the historical stage at the current moment is determined.

5. The automatic polishing control method for aluminum alloy die castings according to claim 4 is characterized in that: The specific steps of determining the historical stage influence degree at the current moment according to the fluctuation situation at each moment in each cycle of each stage of the polishing process of the current aluminum alloy die casting are as follows: The average of the fluctuation conditions at all moments in the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting is used as the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting; According to the method for obtaining the fluctuation condition of the first cycle of the yth stage of the polishing process of the current aluminum alloy die casting, the fluctuation condition of the last cycle of the yth stage of the polishing process of the current aluminum alloy die casting is obtained; The stage at which the current aluminum alloy die casting is in the polishing process at the current moment is recorded as the pth stage; wherein p is a positive integer; When p=1, the historical stage influence degree at the current moment is set to the preset first constant; When p>1, during the polishing process of the current aluminum alloy die-casting, the ratio of the fluctuation situation in the first cycle of the p-th stage to the fluctuation situation in the last cycle of the p-1-th stage is calculated as the first ratio, the inversely proportional normalized value of the absolute value of the difference between the fluctuation situation in the first cycle of the p-1-th stage and the fluctuation situation in the last cycle of the p-1-th stage is calculated as the fluctuation difference of the p-1-th stage, and in all stages before the p-th stage, the sum of the fluctuation differences of all stages is taken as the fluctuation adjustment coefficient, and the sum of the normalized value of the product of the fluctuation adjustment coefficient and the first ratio and the preset first constant is taken as the degree of influence of the historical stage at the current moment.

6. The automatic polishing control method for aluminum alloy die castings according to claim 1 is characterized in that: The specific steps of determining the abnormal situation of the vibration data at the current moment are as follows: The normalized value of the product of the historical stage influence degree at the current moment and the difference of the vibration data at the current moment is used as the abnormality of the vibration data at the current moment.

7. The automatic polishing control method for aluminum alloy die castings according to claim 4 is characterized in that: The specific steps of determining the reference adjustment coefficient at the current moment are as follows: If the abnormality of the vibration data at the current moment is less than or equal to the preset judgment threshold, the reference adjustment coefficient at the current moment is set to the preset second constant; If the abnormality of the vibration data at the current moment is greater than the preset judgment threshold, in the cycle of each stage of the polishing process of the historical aluminum alloy die casting that is the same as the cycle of the stage at the current moment, the vibration data at the moment when the polishing position coordinates are the same as the polishing position coordinates at the current moment is recorded as the target vibration data; The mean of all target vibration data is calculated as a first mean, and a normalized value of a difference between the first mean and the vibration data at the current moment is taken as a reference adjustment coefficient at the current moment.

8. An automatic polishing control device for aluminum alloy die castings, using the automatic polishing control method for aluminum alloy die castings as claimed in any one of claims 1 to 7, characterized in that: The device includes the following modules: Data acquisition module: used to obtain the polishing position coordinates and vibration data of each aluminum alloy die casting at each stage of the polishing process at each moment; Cycle analysis module: used to divide each stage into several cycles according to the polishing position coordinates at each moment; determine the difference of vibration data at each moment according to the difference between vibration data at each moment in adjacent cycles in the same stage; Stage analysis module: used to determine the degree of historical stage influence at the current moment based on the similarity between the vibration data of different aluminum alloy die castings during the polishing process; Abnormal analysis module: used to determine the abnormality of the vibration data at the current moment according to the influence degree of the historical stage at the current moment and the difference of the vibration data at the current moment; Instruction control module: used to determine the reference adjustment coefficient at the current moment according to the abnormal situation of the vibration data at the current moment and the difference in vibration data at the same polishing position coordinates at the same stage and the same cycle of the polishing process of all aluminum alloy die-castings at the corresponding moment; use the reference adjustment coefficient at the current moment as the input of the PID controller and output the control instruction.

9. An automatic polishing control system for aluminum alloy die castings, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is executed by a processor, the steps of the automatic polishing control method for aluminum alloy die castings as described in any one of claims 1 to 7 are implemented.

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