Pneumatic device capable of automatically clamping and intelligent control method

Abstract

The invention relates to the technical field of automatic clamping control, in particular to a pneumatic device capable of achieving automatic clamping and an intelligent control method. According to the device, the adaptive capacity of clamping materials in different shapes is improved through a replaceable modular jaw, and the moment needing to be regulated and controlled is determined by monitoring the vibration state of the materials in the material cleaning process and analyzing a result in an unstable mode; in the occlusion regulation and control process, the vibration influence of the operation of the pneumatic vice is considered, component decomposition analysis is carried out on collected vibration data, the performance of characteristic peak sharpness of a decomposed signal is used for eliminating the interference on the vibration state of a material caused by the influence of the vibration of a mechanism, and a vibration influence signal is obtained; and final stable occlusal force is obtained by combining the unstable condition on the vibration influence signal and occlusal force prediction, and regulation and control clamping is completed through the stable occlusal force. According to the method, the vibration influence interference generated when the vice is started to work is analyzed, so that the occlusal force is more accurately regulated and controlled, and the stability in the material clamping process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic clamping control, and in particular to a pneumatic device capable of automatic clamping and an intelligent control method. Background Art

[0002] Pneumatic vises, also known as pneumatic bench vises, are commonly used clamping tools in industrial production and are widely used in the automotive, machinery, electronics, and other fields. They can be used to secure workpieces and clean them using a cleaning nozzle, achieving a stable and safe cleaning process. Traditional pneumatic vises often require manual manipulation of rockers and utilize pneumatic cylinders to actuate clamping. This relies on the technician's experience to clamp the workpiece, and the unreliability of empirically determined clamping force is a major concern. Therefore, a pneumatic device capable of automatic clamping is urgently needed.

[0003] When existing pneumatic vises are used to clean materials, their key structures are often directly exposed to the cleaning fluid. The cleaning fluid stays between the jaws and the material surface, reducing the friction coefficient. If the bite force is too large, for example, the corners of the material may directly contact the plane where the jaws are located, resulting in wear of the material contour. If the bite force is too small, the material may fall during the cleaning process. In addition, since the vise is in the working state, the vibration of the mechanism will affect the adjustment and judgment of the bite force, resulting in inaccurate bite force regulation and errors. Summary of the Invention

[0004] In order to solve the above problems in the prior art, the purpose of the present invention is to provide a pneumatic device and an intelligent control method for automatic clamping. The technical solutions adopted are as follows:

[0005] The present invention provides an intelligent control method for a pneumatic device capable of automatic clamping, the method comprising:

[0006] During the metal material cleaning process, vibration data is obtained at each sampling moment. Based on the amplitude at each sampling moment and the amplitude fluctuation in the local range, the instability coefficient at each sampling moment is obtained. The start time of bite force control is determined by the size of the instability coefficient.

[0007] After the bite force control starts, the vibration data and bite force are acquired in time series; the vibration data in time series are decomposed, and the characteristic peak sharpness of the decomposed data in the frequency domain is analyzed; the decomposed data is denoised and reconstructed based on the characteristic peak sharpness to obtain the vibration influence signal;

[0008] According to the instability coefficient and bite force size at each moment in the vibration impact signal, a bite force adjustment coefficient is obtained; according to the predicted change of the bite force adjustment coefficient, a final stable bite force is determined; and clamping is controlled based on the final stable bite force.

[0009] Furthermore, the method for obtaining the instability coefficient includes:

[0010] At any sampling moment, within a preset local range at that sampling moment, the maximum and minimum values ​​of the vibration data are obtained; the difference between adjacent maximum and minimum values ​​is used as the amplitude; and the amplitude closest to the sampling moment in time is used as the vibration instability at that sampling moment;

[0011] The amplitudes within a preset local range are arranged in time sequence to obtain a local amplitude sequence at the sampling moment; after calculating the difference between each amplitude in the local amplitude sequence and the previous amplitude, the average of all the differences is calculated to obtain the change instability at the sampling moment;

[0012] The instability coefficient at the sampling moment is obtained by combining the vibration instability and the change instability at the sampling moment.

[0013] Furthermore, the method for determining the start time of bite force regulation includes:

[0014] When the normalized value of the instability coefficient is greater than the preset adjustment threshold, the corresponding sampling moment is used as the starting moment of bite force regulation.

[0015] Furthermore, the method for obtaining the characteristic peak sharpness includes:

[0016] After the bite force control starts, the ICA decomposition algorithm is used on the time series vibration data to obtain regular component signals and random component signals;

[0017] In the frequency domain space of the regular component signal, the kurtosis is calculated and normalized to obtain the characteristic peak sharpness.

[0018] Furthermore, the method for obtaining the vibration impact signal includes:

[0019] The sharpness of the characteristic peak is negatively correlated to obtain the retention weight; the product of the regular component signal and the retention weight is used as the denoising signal, and the denoising signal and the random component signal are reconstructed to obtain the vibration influence signal.

[0020] Furthermore, the method for obtaining the bite force adjustment coefficient includes:

[0021] Based on the vibration data in the vibration impact signal, the instability coefficient at each moment is obtained;

[0022] In the timing of the vibration-affected signal, the product of the instability coefficient and the bite force at the moment is used as the bite force adjustment coefficient at the moment.

[0023] Furthermore, the method for determining the final stable bite force includes:

[0024] The bite force adjustment coefficient in the time series is fitted to obtain the adjustment curve; the adjustment curve is used to predict using the ARIMA algorithm to obtain the predicted bite force adjustment coefficient;

[0025] The bite force corresponding to the minimum value of the bite force adjustment coefficient is taken as the final stable bite force.

[0026] Furthermore, after the bite force regulation starts, the bite force is increased from the minimum value in the expected bite force range, and vibration data and bite force at each moment are collected.

[0027] Furthermore, after the bite force regulation starts, when the bite force reaches the final stable bite force, the regulation is stopped to complete the clamping.

[0028] The present invention also provides a pneumatic device capable of automatic clamping, comprising a vise mechanism, a transmission mechanism, and a control mechanism; the vise mechanism comprises replaceable modular jaws for biting metal materials; the transmission mechanism comprises a cylinder mechanism and a self-locking mechanism; the control mechanism comprises a collection unit, a data processing unit, and a control unit;

[0029] The signal output end of the acquisition unit is connected to the signal input end of the data processing unit, and the signal output end of the data processing unit is connected to the signal input end of the control unit, and the control unit is used to output control instructions to the transmission mechanism;

[0030] The acquisition unit acquires vibration data at each sampling moment through a vibration sensor and acquires the bite force exerted on the material through a pressure sensor; and transmits the acquired data to a data processing unit;

[0031] The data processing unit is used to obtain the instability coefficient at each sampling moment according to the amplitude at each sampling moment and the amplitude fluctuation in the local range during the metal material cleaning process; and determine the start time of bite force control according to the magnitude of the instability coefficient;

[0032] After the bite force control starts, the vibration data in the time series is decomposed and the characteristic peak sharpness of the decomposed signal in the frequency domain is analyzed. Based on the characteristic peak sharpness, the decomposed signal is denoised and reconstructed to obtain the vibration impact signal.

[0033] Obtaining a bite force adjustment coefficient based on the instability coefficient and bite force magnitude at each moment in the vibration impact signal; determining a final stable bite force based on the predicted change of the bite force adjustment coefficient;

[0034] The bite force regulation start time and the final stable bite force are transmitted to the transmission mechanism through the control unit. The cylinder mechanism runs after the bite force regulation start time, and the cylinder mechanism operation stop is determined and the self-locking mechanism is clamped according to the final stable bite force.

[0035] The present invention has the following beneficial effects:

[0036] The present invention improves the adaptability of clamping materials of different shapes through replaceable modular jaws, monitors the vibration state of the material during the material cleaning process, and determines the time when regulation is required based on the unstable analysis results. During the bite regulation process, the vibration influence of the pneumatic vise operation is taken into account, and the collected vibration data is decomposed and analyzed by the sharpness of the characteristic peaks to suppress the regular components, eliminate the interference of the mechanism's own vibration state on the material's own vibration state, and obtain a vibration influence signal. The final stable bite force is obtained by combining the instability of the vibration influence signal with the bite force prediction, and the regulated clamping is completed by stabilizing the bite force. The present invention analyzes the vibration influence interference that starts the vise work, makes the bite force regulation more precise, and improves the stability during the material clamping process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. 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 any creative work.

[0038] Figure 1 A flow chart of an intelligent control method for an automatic clamping pneumatic device provided by one embodiment of the present invention;

[0039] Figure 2 A schematic structural diagram of an automatic clamping pneumatic device provided by one embodiment of the present invention;

[0040] Figure 3 Another schematic structural diagram of an automatic clamping pneumatic device provided by one embodiment of the present invention;

[0041] Figure 4 A schematic top view of the structure of an automatic clamping pneumatic device provided by one embodiment of the present invention;

[0042] Figure 5 A schematic front view of the structure of an automatic clamping pneumatic device provided by one embodiment of the present invention;

[0043] Figure 6 A partial top view of a modular jaw of a pneumatic device capable of automatic clamping provided by one embodiment of the present invention;

[0044] In conjunction with the accompanying drawings, the following reference numerals are marked on the drawings: 1. Self-locking mechanism; 2. Fixed jaws; 3. Screw; 4. Movable jaws; 5. Slider nut; 6. Threaded shaft; 7. Threaded shaft gear; 8. Transmission gear; 9. Central processing unit and central control panel; 10. Cylinder mechanism; 11. Base; 12. Vibration sensor; 13. Modular jaws; 131. Dovetail tenon; 14. Pressure sensor. DETAILED DESCRIPTION

[0045] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of a pneumatic device and intelligent control method for automatic clamping according to the present invention. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0046] 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.

[0047] The following is a detailed description of the specific scheme of the pneumatic device and intelligent control method for automatic clamping provided by the present invention in conjunction with the accompanying drawings. Figures 2 to 6 A vise mechanism for an automatic clamping pneumatic device includes a fixed jaw 2, a screw 3, a movable jaw 4, a slider nut 5, a base 11, a modular jaw 13, and a dovetail joint 131. The transmission mechanism includes a self-locking mechanism 1, a threaded shaft 6, a threaded shaft gear 7, a transmission gear 8, and a cylinder mechanism 10. The control mechanism includes a vibration sensor 12, a pressure sensor 14, a central processing unit, and a central control panel 9.

[0048] Among them, the base 11 is equipped with a transmission mechanism and a vise mechanism. At the same time, in order to avoid excessive accumulation of cleaning liquid in the entire mechanism and groove during material cleaning, there is an opening below the base 11, that is, below the 6-threaded shaft, to drain the cleaning liquid.

[0049] The fixed jaw 2 and the movable jaw 4 in the vise mechanism are fixed at both ends by a smooth screw 3, so that the two can move along the screw 3. The fixed jaw 2 can be adjusted manually so that it can cope with materials of different forms. The movable jaw 4 is fixed on the slider nut 5, and the slider nut 5 is connected to the threaded shaft 6. The movable jaw 4 can be adjusted manually or by equipment in a dual-mode manner. At this time, when the movable jaw 4 is fixed, the threaded shaft 6 itself does not move. The slider nut 5 is also fixed on the movable jaw 4 and the screw 3, so the transmission gear 8 is rotated by the cylinder mechanism 10 and drives the threaded shaft gear 7 and the threaded shaft 6 to rotate, so that the slider nut 5 moves back and forth along the thread direction of the threaded shaft 6, thereby driving the movable jaw 4 to move and realize biting the material.

[0050] Because different materials have different complex external contours, a larger bite force is usually used to stabilize the material. However, using parallel jaws may not be able to stably bite the material. If the bite force is too large, for example, the corners of the material may directly contact the plane where the jaws are located, causing the material contour to wear. If the bite force is too small, it may cause the material to fall during the cleaning process. Therefore, in order to ensure that the jaws can bite the material more firmly, the vise mechanism adopts replaceable modular jaws 13. The contact surface profile of the modular jaws 13 and the material can be designed according to actual needs. The modular jaws 13 are connected to the fixed jaws 2 and the movable jaws 4 using a dovetail tenon 131, which can be replaced by pulling perpendicular to the base plane 11.

[0051] As for the transmission mechanism, since the automatic clamping pneumatic device is used to clean metal workpieces, it is necessary to minimize the area of ​​the device itself exposed to the cleaning fluid, especially the power and transmission structures, to prevent oxidation and corrosion. Therefore, the cylinder mechanism 10 is placed outside the base 11 and connected to the transmission gear 8 to provide power to rotate the transmission gear 8.

[0052] Conventional pneumatic vises typically have the jaws fixed to a smooth lead screw, with a cylinder providing power to move the jaws. In this embodiment, the rod that drives the jaws is configured as a threaded shaft 6, and the portion of the threaded shaft 6 that extends outside the base 11 is configured as a threaded shaft gear 7, which meshes with a transmission gear 8.

[0053] At the same time, during the clamping process, the ultimate forces exerted on different materials, i.e., the ultimate forces exerted when deforming, vary, requiring more precise control of the bite force. Therefore, the transmission gear 8 has a larger diameter and more teeth, while the corresponding threaded shaft gear 7 has a relatively smaller diameter and fewer teeth. This allows for greater precision in regulating the bite force when the cylinder mechanism 10 rotates the transmission gear 8, driving the threaded shaft gear 7 and the threaded shaft 6.

[0054] To prevent sudden drops in power output from the cylinder mechanism 10 due to factors such as cylinder failure and power outages, ensure greater stability after the vise mechanism clamps the material, and reduce energy consumption during the cleaning process, a self-locking mechanism 1 is employed on the other side of the threaded shaft 6 where it extends from the base 11. This mechanism is in an unlocked state when the cylinder mechanism 10 is outputting power. If the power output of the cylinder mechanism 10 drops abnormally or the vise has reached a predetermined engagement force, the threaded shaft 6 is secured and locked to prevent reverse rotation, which would otherwise reduce engagement force.

[0055] It should be noted that, in the mechanical analysis, for example, for two jaws that are parallel to each other and perpendicular to the horizontal plane, when there is material between them, the material itself is affected by the vertical downward gravity, the horizontal jaw pressure, and the vertical upward friction between the jaws and the material. It is known that the jaw pressures on both sides cancel each other out. In order to balance the material, the gravity of the material and the friction between the jaws and the material should be the same. Therefore, the friction is increased by adjusting the bite force.

[0056] Due to the different shapes, structures and material properties of the materials to be clamped, there are differences in the ultimate forces during deformation. When manual control is used, there is a high probability of large bite force errors, causing deformation, wear, or even falling of the materials. Therefore, automatic adjustment is performed through the control mechanism.

[0057] In the process of cleaning metal materials, the water pressure usually used is relatively high. At this time, when the material comes into contact with high-pressure water, it may produce a certain degree of vibration. At the same time, the cleaning liquid stays on the surface of the jaws and the material, reducing the friction coefficient. At this time, the vibration will cause the balance relationship between the material and the jaws to fluctuate, even if the friction force is reduced, the material may be displaced or even fall. Therefore, it is necessary to monitor the vibration of the material in real time to regulate the power output of the cylinder mechanism 10, thereby adjusting the bite force.

[0058] Because the forces act mutually, and the ultimate force upon deformation can be determined based on the material's specifications and quality requirements, a pressure sensor 14 is installed on the surface between the jaws and the modular jaws 13 to monitor the force during the engagement process. Furthermore, operational vibrations are transmitted through the medium, so a vibration sensor 12 is installed on the fixed jaws 4 to collect vibration data.

[0059] The control mechanism includes an acquisition unit, a data processing unit, and a control unit. The acquisition unit uses a vibration sensor 12 and a pressure sensor 14 to acquire vibration data and bite force at each sampling moment, monitoring the vibration and bite force of the pneumatic vise during the cleaning and control process. The acquired data is transmitted to the data processing unit, which analyzes and processes it through a high-speed central processing unit installed on the cylinder mechanism 10 and the central control panel 9. The control results are then transmitted to the control unit for subsequent feedback and control.

[0060] The methods of analysis and control by regulatory agencies refer to Figure 1 , which shows a flow chart of an intelligent control method for an automatic clamping pneumatic device provided by one embodiment of the present invention, the method comprising the following steps:

[0061] S1: During the metal material cleaning process, the vibration data at each sampling moment is obtained; based on the amplitude at each sampling moment and the amplitude fluctuation in the local range, the instability coefficient at each sampling moment is obtained; and the start time of bite force control is determined by the size of the instability coefficient.

[0062] When the material itself is clamped and in a state of equilibrium, it is subjected to lateral pressure from the jaws on both sides, which together keep the material in a stationary state relative to the clamping device. After the metal material comes into contact with the high-pressure water used for cleaning, it may produce a certain degree of vibration. The vibration is transmitted through the medium, and the vibration during the cleaning process can be monitored by the installed sensor. In this embodiment of the present invention, the sampling time interval of the vibration data can be set to 0.5 seconds. The specific sampling frequency can be adjusted by the implementer according to the specific implementation scenario and is not limited here.

[0063] The greater the vibration amplitude of the material, the greater the decrease in the friction coefficient caused by the cleaning fluid, the worse the stability at this time, and the higher the need for bite adjustment. Therefore, the instability characteristics are analyzed by the amplitude at each sampling moment. In an embodiment of the present invention, the method for obtaining the instability coefficient at each sampling moment includes:

[0064] At any sampling moment, within a preset local range at that sampling moment, the maximum and minimum values ​​of the vibration data are obtained. The difference between adjacent maximum and minimum values ​​is used as each amplitude. To analyze the influence of vibration amplitude, the amplitude is reflected by the amplitude of the extreme value change in the local range. There is an amplitude between each adjacent minimum and maximum value. In this embodiment, a range with a side length of 10 seconds centered at each sampling moment is set as the preset local range. The specific selection of the local range is subject to adjustment by the implementer.

[0065] The larger the amplitude at the sampling moment, the higher the instability of the material at that moment. The amplitude closest to the sampling moment in time sequence is taken as the vibration instability at that sampling moment.

[0066] Considering the continuous decrease in amplitude caused by the cleaning fluid, the amplitudes within a preset local range are arranged in chronological order to obtain a local amplitude sequence at that sampling moment. The amplitude fluctuations over this time series are analyzed. The difference between each amplitude in the local amplitude sequence and the previous amplitude is calculated, and the average of all differences is taken as the degree of change instability at that sampling moment. A positive and increasing degree of change instability indicates a greater degree of continuous change in the material due to the impact, and a higher degree of instability.

[0067] Finally, the instability coefficient at that sampling moment is obtained by combining the vibration instability and the variable instability. In this embodiment of the present invention, the Euclidean norm between the vibration instability and the variable instability is calculated to obtain the instability coefficient. By combining the Euclidean norm, the greater the vibration instability and the variable instability, the greater the impact on the current material. In other embodiments of the present invention, the product of the vibration instability and the variable instability can also be used as the instability coefficient, which will not be explained here.

[0068] The more severe the instability of the vibration sequence, the more likely it is that the material needs to be adjusted to ensure stable clamping under high-pressure water impact. In this embodiment of the present invention, when the normalized value of the instability coefficient is greater than a preset adjustment threshold, it indicates that the clamping stability is poor and clamping adjustment is required. The corresponding sampling time is used as the starting point for clamping force adjustment. The preset adjustment threshold is set to 0.5, and the specific value can be adjusted by the implementer.

[0069] It should be noted that normalization is a technical means well known to those skilled in the art. The normalization options may be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0070] S2: After the bite force control starts, the vibration data and bite force are obtained in time series; the vibration data in time series are decomposed and the characteristic peak sharpness of the decomposed data in the frequency domain is analyzed; the decomposed data is denoised and reconstructed based on the characteristic peak sharpness to obtain the vibration impact signal.

[0071] The start time of bite force control is transmitted to the transmission mechanism via the control unit, activating the cylinder mechanism for bite control. The vise has a specified increase or decrease coefficient when increasing or decreasing bite force. This means that the value of the bite force control changes steadily over time. Therefore, the rated gear speed can be obtained based on the cylinder specifications, and the bite force adjustment is a linear process.

[0072] Because the range of bite force varies depending on the material, it is necessary to determine the allowable range of bite force for the clamped material in advance during bite force clamping adjustment, so that the subsequently adjusted bite force falls within the expected bite force range. In this embodiment of the present invention, the maximum bite force is input as the current material's maximum force. Based on a priori characteristics such as the angle between the contact surface between the material and the jaws and the horizontal plane, and the material mass, a mechanical analysis is performed to directly output the minimum bite force at material equilibrium, thereby obtaining the expected bite force range for the corresponding material.

[0073] When adjusting the actual force applied to the material, the greater the force, the greater the probability of deformation and the higher the instability. Therefore, when adjusting the bite force, the final bite force should be as small as possible. Therefore, after the bite force control begins, the bite force is set from the minimum value in the expected bite force range and increases linearly according to the rated power of the cylinder mechanism. During this process, the bite force applied to the material and vibration data are continuously monitored and collected to analyze the optimal bite force.

[0074] When the pneumatic vise is in working condition, the automatic locking structure is unlocked, and the cylinder mechanism, gears, screw shaft and other mechanisms will generate certain vibrations. This vibration is transmitted through each mechanism and will also be collected by the vibration sensor, resulting in interference in the collected vibration data, which will cause errors in the final control of the bite force. Therefore, the vibration data needs to be denoised.

[0075] Because the vibration generated by the vise itself during operation is more stable than that caused by high-pressure water impacting an object, and its random variation is less pronounced, signal decomposition can be used for noise reduction analysis. Since the vibration signal is a mixture of regular signals from the vise's operation and random signals from material cleaning, noise reduction can usually be achieved by setting the regular signal portion to zero.

[0076] However, the vibration generated by the actual pneumatic vise has certain interference components, and the vibration transmission situation causes the components to be not completely regular. Therefore, if the noise is directly set to zero, the vibration signal characteristics of some random components may be lost. Therefore, considering spectrum analysis, the denoising degree is adjusted through the peak characteristics of the regular components to obtain a more accurate vibration impact signal.

[0077] First, the vibration data in the time series is decomposed, and the characteristic peak sharpness of the decomposed data in the frequency domain is analyzed. In an embodiment of the present invention, the method for obtaining the characteristic peak sharpness includes:

[0078] After the start of bite force control, the ICA decomposition algorithm is applied to the vibration data in the time series to obtain regular component signals and random component signals. In this embodiment, the ICA decomposition algorithm can be used to decompose the vibration signal mixed in the time series into statistically independent components, and remove the DC component of the signal. The DC component refers to the mean or constant offset part in the signal. If there is a significant DC component in the signal, it will appear as zero frequency in the spectrum analysis, that is, the peak at DC, covering up other frequency components. The remaining signal is whitened to eliminate the second-order correlation between the channels. Then, the autocorrelation function of the decomposed component is calculated, and the regular and random components are clearly distinguished through time domain periodicity verification. The autocorrelation function of the regular periodic signal retains the frequency characteristics, while the random component will decay rapidly, obtaining the final regular component signal and random component signal.

[0079] It should be noted that the ICA decomposition algorithm, whitening processing and calculation of the autocorrelation function are all technical means well known to those skilled in the art and are not described in detail here.

[0080] Due to the different manifestations of different components in the frequency domain, the regular component appears as a single frequency peak in the spectrum, while the random component spectrum has no significant peak. Therefore, the sharper the peak representing the regular component, the greater the component content and the greater the need for elimination. Therefore, in the frequency domain of the regular component signal, the kurtosis is calculated and normalized to obtain the characteristic peak sharpness. The magnitude of the calculated kurtosis characterizes the steepness and sharpness of the peak. The greater the kurtosis, the higher the sharpness. It should be noted that frequency domain conversion and kurtosis calculation are both well-known technical means well known to those skilled in the art. Fast Fourier transform is used to convert the signal to frequency domain space analysis, which will not be described in detail here.

[0081] In other embodiments of the present invention, the peak size of the regular component signal can be obtained as the extreme sharpness value; a larger value indicates greater sharpness. The range of the peak frequency domain range is used as the characteristic distribution value; a smaller value indicates greater sharpness. The ratio of the extreme value to the characteristic distribution value is normalized and used as the characteristic peak sharpness, reflecting the degree of sharpness.

[0082] Therefore, the decomposed data is denoised and reconstructed based on the sharpness of the characteristic peak to obtain the vibration impact signal. The greater the sharpness of the characteristic peak, the more significant the regular component is, the greater the degree of elimination, and the smaller the signal retention.

[0083] Therefore, in this embodiment of the present invention, a negative correlation mapping is performed on the sharpness of the characteristic peaks to obtain a retention weight. The retention weight represents the degree to which the regular component needs to be retained. The product of the regular component signal and the retention weight is used as the denoised signal. The denoised signal and the random component signal are reconstructed to obtain the vibration influence signal, thereby obtaining a signal that removes the influence of the starting vise's own vibration.

[0084] It should be noted that negative correlation mapping and signal reconstruction are technical means well known to those skilled in the art. For example, negative correlation mapping uses inverse proportional values ​​or negative exponential power forms, and signal reconstruction can also use wavelet transform, etc., which are not limited or elaborated here.

[0085] S3: Obtain a bite force adjustment coefficient based on the instability coefficient and bite force magnitude at each moment in the vibration impact signal; determine a final stable bite force based on the predicted change of the bite force adjustment coefficient; and control clamping based on the final stable bite force.

[0086] By removing the vibration influence signal after the influence, the subsequent instability and bite force are analyzed. At this time, during the bite force adjustment process, the greater the bite force, the greater the vibration suppression effect. At this time, the smaller the instability, that is, the smaller the amplitude change, the better. Therefore, the instability coefficient corresponding to the bite force is finally combined to determine a more stable bite force size.

[0087] The bite force adjustment coefficient is obtained based on the instability coefficient and bite force size at each moment in the vibration influence signal. In an embodiment of the present invention, the instability coefficient at each moment is obtained based on the vibration data in the vibration influence signal. The calculation method of the instability coefficient at each moment is the same as that in step S1 and will not be repeated here.

[0088] Then, in the timing of the vibration-affected signal, the product of the instability coefficient at the moment and the bite force is used as the bite force adjustment coefficient at the moment. When the instability is smaller, the bite force is made smaller to ensure clamping while protecting the material shape.

[0089] Subsequent predictions can be made based on the changes in the bite force adjustment coefficient, so that the expected optimal situation can be analyzed through real-time prediction. In an embodiment of the present invention, the method for obtaining the final stable bite force includes:

[0090] The bite force adjustment coefficient in the time series is fitted to obtain the adjustment curve, and the ARIMA algorithm is used to predict the adjusted curve to obtain the predicted bite force adjustment coefficient. It should be noted that curve fitting and ARIMA algorithm prediction are both technical means well known to those skilled in the art. Curve fitting can use the least squares method, etc., which will not be elaborated here.

[0091] Finally, the bite force corresponding to the minimum value of the bite force adjustment coefficient is taken as the final stable bite force. The minimum bite force adjustment coefficient is the minimum bite force under the optimal stability condition, which represents the optimal pressure condition for clamping and cleaning.

[0092] Therefore, the clamping is controlled according to the final stable bite force, and the final stable bite force will be transmitted to the transmission mechanism through the control unit. When the bite force reaches the final stable bite force, the operation of the cylinder mechanism and the bite force adjustment are stopped, and the self-locking mechanism locks the spiral shaft to realize automatic clamping.

[0093] In summary, the present invention improves the adaptability of clamping materials of different shapes through replaceable modular jaws, monitors the vibration state of the material during the material cleaning process, and uses unstable analysis results to determine the time when regulation is required. During the bite regulation process, the vibration influence of the pneumatic vise operation is taken into account, and the collected vibration data is decomposed and analyzed by the sharpness of the characteristic peaks to suppress the regular components, eliminate the interference of the mechanism's own vibration state on the material's own vibration state, and obtain a vibration influence signal. The final stable bite force is obtained by combining the instability of the vibration influence signal with the bite force prediction, and the regulated clamping is completed by stabilizing the bite force. The present invention analyzes the vibration influence interference of the start-up vise work, makes the bite force regulation more accurate, and improves the stability of the material clamping process.

[0094] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0095] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. An intelligent control method for a pneumatic device capable of automatic clamping, characterized in that: The method comprises: During the metal material cleaning process, vibration data is obtained at each sampling moment. Based on the amplitude at each sampling moment and the amplitude fluctuation in the local range, the instability coefficient at each sampling moment is obtained. The start time of bite force control is determined by the size of the instability coefficient. After the bite force control starts, the vibration data and bite force are acquired in time series; the vibration data in time series are decomposed, and the characteristic peak sharpness of the decomposed data in the frequency domain is analyzed; the decomposed data is denoised and reconstructed based on the characteristic peak sharpness to obtain the vibration influence signal; According to the instability coefficient and bite force size at each moment in the vibration impact signal, a bite force adjustment coefficient is obtained; according to the predicted change of the bite force adjustment coefficient, a final stable bite force is determined; and clamping is controlled based on the final stable bite force.

2. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for obtaining the instability coefficient includes: At any sampling moment, within a preset local range at that sampling moment, the maximum and minimum values ​​of the vibration data are obtained; the difference between adjacent maximum and minimum values ​​is used as the amplitude; and the amplitude closest to the sampling moment in time is used as the vibration instability at that sampling moment; The amplitudes within a preset local range are arranged in time sequence to obtain a local amplitude sequence at the sampling moment; after calculating the difference between each amplitude in the local amplitude sequence and the previous amplitude, the average of all the differences is calculated to obtain the change instability at the sampling moment; The instability coefficient at the sampling moment is obtained by combining the vibration instability and the change instability at the sampling moment.

3. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for determining the start time of bite force regulation includes: When the normalized value of the instability coefficient is greater than the preset adjustment threshold, the corresponding sampling moment is used as the starting moment of bite force regulation.

4. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for obtaining the characteristic peak sharpness includes: After the bite force control starts, the ICA decomposition algorithm is used on the time series vibration data to obtain regular component signals and random component signals; In the frequency domain space of the regular component signal, the kurtosis is calculated and normalized to obtain the characteristic peak sharpness.

5. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for obtaining the vibration impact signal includes: The sharpness of the characteristic peak is negatively correlated to obtain the retention weight; the product of the regular component signal and the retention weight is used as the denoising signal, and the denoising signal and the random component signal are reconstructed to obtain the vibration influence signal.

6. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for obtaining the bite force adjustment coefficient includes: Based on the vibration data in the vibration impact signal, the instability coefficient at each moment is obtained; In the timing of the vibration-affected signal, the product of the instability coefficient and the bite force at the moment is used as the bite force adjustment coefficient at the moment.

7. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: The method for determining the final stable bite force includes: The bite force adjustment coefficient in the time series is fitted to obtain the adjustment curve; the adjustment curve is used to predict using the ARIMA algorithm to obtain the predicted bite force adjustment coefficient; The bite force corresponding to the minimum value of the bite force adjustment coefficient is taken as the final stable bite force.

8. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: After the bite force control starts, the bite force is increased from the minimum value in the expected bite force range, and the vibration data and bite force at each moment are collected.

9. The intelligent control method for an automatically clamping pneumatic device according to claim 1, characterized in that: After the bite force regulation starts, when the bite force reaches the final stable bite force, the regulation is stopped to complete the clamping.

10. A pneumatic device capable of automatic clamping, characterized in that: It includes a vise mechanism, a transmission mechanism and a control mechanism; the vise mechanism includes replaceable modular jaws for biting metal materials; the transmission mechanism includes a cylinder mechanism and a self-locking mechanism; the control mechanism includes a collection unit, a data processing unit and a control unit; The signal output end of the acquisition unit is connected to the signal input end of the data processing unit, and the signal output end of the data processing unit is connected to the signal input end of the control unit, and the control unit is used to output control instructions to the transmission mechanism; The acquisition unit acquires vibration data at each sampling moment through a vibration sensor and acquires the bite force exerted on the material through a pressure sensor; and transmits the acquired data to a data processing unit; The data processing unit is used to obtain the instability coefficient at each sampling moment according to the amplitude at each sampling moment and the amplitude fluctuation in the local range during the metal material cleaning process; and determine the start time of bite force control according to the magnitude of the instability coefficient; After the bite force control starts, the vibration data in the time series is decomposed and the characteristic peak sharpness of the decomposed signal in the frequency domain is analyzed. Based on the characteristic peak sharpness, the decomposed signal is denoised and reconstructed to obtain the vibration impact signal. Obtaining a bite force adjustment coefficient based on the instability coefficient and bite force magnitude at each moment in the vibration impact signal; determining a final stable bite force based on the predicted change of the bite force adjustment coefficient; The bite force regulation start time and the final stable bite force are transmitted to the transmission mechanism through the control unit. The cylinder mechanism runs after the bite force regulation start time, and the cylinder mechanism operation stop is determined and the self-locking mechanism is clamped according to the final stable bite force.

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