Coordinated control method of shot blasting equipment for double-sided compensation processing

Abstract

The invention belongs to the technical field of industrial automation control, and particularly relates to a shot blasting equipment coordination control method for double-sided compensation machining, which comprises the following steps of: performing time sequence alignment on robot tail end pose data and pressure data, calculating an original relative pose efficiency coefficient according to a real-time spraying distance and a real-time incident angle, and calculating a real-time spraying distance; performing moving average filtering to obtain a smooth efficiency coefficient; calculating theoretical compensation pressure according to the smooth efficiency coefficient and carrying out physical boundary constraint to obtain a control instruction; and the deviation between the control instruction and the actual pipeline pressure is calculated, hysteresis compensation is conducted on the control instruction in combination with the gas path response time constant, and a final execution instruction is obtained and sent to the electric proportional valve. According to the method, the problems of non-uniform energy density caused by geometric attitude fluctuation and dislocation compensation caused by gas circuit response hysteresis in double-sided shot blasting machining are solved, distortion of weak-rigidity parts is eliminated, and the surface strengthening quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial automation control. More particularly, the present application relates to a method for coordinated control of a shot blasting device for double-sided compensation machining. BACKGROUND

[0002] In the field of aerospace high-end manufacturing, key components such as aircraft engine blades and wing panels generally have significant weak rigidity and thin-wall characteristics, and are prone to deformation during machining due to uneven stress. Double-robot mirror image shot blasting technology, as an advanced surface strengthening method, is widely used in the anti-fatigue manufacturing of such parts by controlling the synchronous movement of the two robots and using the impact force of the counter-attacking bullet stream to offset the macro bending moment introduced by single-sided machining. However, the current mainstream double-machine cooperative control strategy is mostly limited to geometric synchronization of spatial trajectory and static constancy of process parameters, i.e., setting both sides of the shot gun to output the same preset air pressure throughout the path. This control mode lacks feedback, ignores the geometric time-varying factors in the dynamic machining environment, and is difficult to meet the high-precision strengthening needs of complex curved surface parts.

[0003] In actual machining of wide-chord blades with large torsion or complex double-curvature panels, due to the limitations of joint degrees of freedom of industrial robot bodies, kinematic singularity avoidance requirements, and discrete characteristics of trajectory planning, the actual physical pose of the nozzle end relative to the workpiece surface is often difficult to maintain at the ideal process setting value at all times, and fluctuations in the actual shot distance and deviations in the incident angle are inevitable. According to the principles of jet dynamics and energy transfer, the energy density distribution of the bullet beam driven by high-pressure gas is significantly sensitive to the geometric pose during spatial propagation. Specifically, an increase in the shot distance will cause the bullet stream to diverge in cross section under the action of air resistance and diffusion, resulting in a non-linear decay of the impact kinetic energy density per unit area. The inclination of the incident angle will significantly reduce the component of the impact momentum in the normal direction of the workpiece surface, thereby weakening the effective strengthening effect. This imbalance in bilateral kinetic energy flux caused by fluctuations in the geometric pose of the robot movement will lead to a serious asymmetry in the residual stress field distribution introduced on both sides of the workpiece, thereby breaking the mechanical equilibrium state and causing weak rigid thin-walled parts to still have size out-of-tolerance problems such as twisting and bending after double-sided mirror image precision machining. SUMMARY

[0004] To solve the technical problem that the current control strategy ignores the geometric pose fluctuations, leading to imbalance in bilateral kinetic energy flux and causing weak rigid parts to still have twisting deformation after machining, the present application provides a method for coordinated control of a shot blasting device for double-sided compensation machining, comprising: For the left and right robots, the corresponding final execution instructions are generated based on the respective data channels, including: determining an original relative attitude performance coefficient according to the real-time spraying distance and the real-time incident angle of the robot, performing sliding average filtering on the original relative attitude performance coefficient to obtain a smooth performance coefficient; calculating a theoretical compensation pressure according to the smooth performance coefficient, performing physical boundary constraint on the theoretical compensation pressure, and generating a control instruction sent to the electric proportional valve; collecting the actual pipeline pressure by using the pressure sensor installed at the end of the spray gun, calculating the deviation of the control instruction and the actual pipeline pressure, and introducing a hysteresis compensation term based on the gas path response time constant to correct the control instruction to obtain the final execution instruction; and sending the final execution instruction to the electric proportional valve to control the shot pressure.

[0005] The original relative attitude performance coefficient is calculated and sliding average filtering is performed, the influence of the spraying distance and the incident angle on the energy density is measured, high-frequency noise caused by curvature mutation is filtered out, and frequent action and mechanical oscillation of the electric proportional valve are avoided; the theoretical compensation pressure is calculated and amplitude limiting is performed, adaptive energy compensation based on the geometric attitude is realized, the uniformity of the effective impact kinetic energy density acting on the workpiece surface is ensured, and the equipment safety is protected; the hysteresis compensation term is introduced, the integral algorithm is used to correct the historical error, the final execution instruction can predict and offset the physical hysteresis of the gas path system, the pressure accurately follows the robot trajectory, and the residual stress field distortion causing the part deformation is eliminated.

[0006] Preferably, it further comprises: establishing a unified time reference axis, buffering and time sequence aligning the end pose data uploaded on the robot controller and the pressure data uploaded by the sensor, the end pose data including the real-time spraying distance and the real-time incident angle of the robot, and the pressure data being the actual pipeline pressure collected by the pressure sensor installed at the end of the spray gun.

[0007] Preferably, the original relative attitude performance coefficient satisfies the expression: ; in the expression, represents the original relative attitude performance coefficient at the moment t; represents the standard optimal spraying distance set in the process; represents the real-time spraying distance of the robot at the moment t; represents the real-time incident angle at the moment t. represents the real-time spraying distance of the robot at the moment t; represents the real-time incident angle at the moment t. represents the real-time incident angle at the moment t.

[0008] This invention utilizes the jet diffusion principle and momentum decomposition principle to obtain the original relative attitude efficiency coefficient, where the distance term reflects the energy dilution caused by jet diffusion and the angle term reflects the normal momentum decay caused by oblique incidence. It can accurately measure the energy transfer efficiency under the current geometric attitude and provide a precise physical basis for subsequent pressure compensation.

[0009] Preferably, the smoothing efficiency coefficient satisfies the expression: In the formula, express The smoothing efficiency coefficient at any given time; This indicates the window size for the moving average filter; Indicates the sampling interval; express The original relative attitude efficiency coefficient at time.

[0010] Preferably, the theoretical compensation pressure satisfies the expression: In the formula, express Theoretical compensation pressure at any moment; This indicates the reference shot peening pressure specified in the process procedure; Indicates the compensation gain factor; express The smoothing efficiency coefficient at any given time.

[0011] This invention constructs a feedforward compensation model based on the inverse of efficiency. When the geometric attitude deteriorates, causing the smoothing efficiency coefficient to decrease, the system can automatically calculate the required pressurization amount. By increasing the shot peening air pressure, the initial velocity and mass flow rate of the shot are increased, thereby compensating for the energy flux loss caused by the increased distance or tilted angle, and ensuring the uniform depth of the strengthening layer on the workpiece surface.

[0012] Preferably, the step of physically constraining the theoretical compensation pressure and generating a control command to be sent to the electro-proportional valve includes: setting the control command to the lower limit of the safe operating pressure in response to the theoretical compensation pressure being less than the lower limit of the safe operating pressure; setting the control command to the theoretical compensation pressure in response to the theoretical compensation pressure being greater than or equal to the lower limit of the safe operating pressure and less than or equal to the upper limit of the safe operating pressure; and setting the control command to the upper limit of the safe operating pressure in response to the theoretical compensation pressure being greater than the upper limit of the safe operating pressure.

[0013] This invention, by setting physical boundary constraints, prevents equipment damage or alarms caused by the calculated theoretical compensation pressure exceeding the physical tolerance limit of the electric proportional valve or pipeline, ensuring that control commands are always within the safe operating range of the system, and guaranteeing the continuity and safety of shot peening operations.

[0014] Preferably, the final execution instruction satisfies the expression: ; wherein, represents the final execution instruction sent to the electric proportional valve at the moment; represents the control instruction at the moment; represents the hysteresis compensation coefficient; represents the air path response time constant of the system; represents the control instruction at the moment within the integral interval; represents the control instruction at the moment within the integral interval; represents the actual pipeline pressure fed back by the sensor at the moment within the integral interval; represents the actual pipeline pressure fed back by the sensor at the moment within the integral interval.

[0015] The present application introduces an integral-based hysteresis compensation mechanism, which calculates the average deviation between the control instruction and the actual pressure in the past period of time and superimposes it into the current instruction, effectively offsets the delay caused by the physical processes such as compressed air transmission and valve core action, eliminates the misalignment compensation error caused by the pressure response lag, and improves the dynamic performance of the pressure control.

[0016] Preferably, the method for obtaining the air path response time constant is: in the system idle state, a step instruction signal from zero pressure to the reference working pressure is sent to the electric proportional valve; the pressure change curve at the end of the spray gun is recorded in real time by using a high-frequency pressure sensor; and the time span required for the pressure to rise from the moment when the step instruction is issued to 63.2% of the final steady-state pressure is taken as the air path response time constant of the system.

[0017] The present application can accurately reflect the total physical hysteresis characteristics of the system including the electric proportional valve response, pipeline charging delay and large flow valve action delay by obtaining the air path response time constant through the standardized step response test, thereby providing a basis for hysteresis compensation.

[0018] Preferably, the real-time incident angle is the included angle between the spray gun axis vector and the normal vector of the current point on the workpiece surface.

[0019] Preferably, the sending of the final execution instruction to the electric proportional valve to control the shot blasting pressure comprises: converting the final execution instructions of the left and right robots into voltage signals or current signals and sending them to the corresponding electric proportional valves.

[0020] The beneficial effects of the present application are that: the present application establishes a unified time reference axis and time-aligns the end position data uploaded on the robot controller and the pressure data uploaded on the sensor, eliminates the time difference of data transmission between the industrial field bus and the acquisition card, ensures the synchronization of the position data and the pressure data, and establishes independent data channels for the left and right robots respectively and independently generates the final execution instruction, which can adapt to the processing needs of the blade and other asymmetric workpieces and realize the precise cooperation of both sides; the present application calculates the original relative attitude performance coefficient and performs sliding average filtering, measures the influence of the real-time spraying distance and the real-time incident angle on the energy density, filters out the high-frequency noise caused by the sudden change of the workpiece surface curvature, and avoids the frequent action of the electric proportional valve and the mechanical oscillation; the present application calculates the theoretical compensation pressure according to the smooth performance coefficient and performs physical boundary constraint, realizes the adaptive energy compensation based on the geometric attitude, ensures the uniformity of the effective impact kinetic energy density acting on the workpiece surface, and prevents the equipment damage caused by pressure overload; the present application introduces the hysteresis compensation term, corrects the historical error by using the integral algorithm, so that the final execution instruction can predict and offset the physical hysteresis of the gas circuit system, realizes the pressure following of the robot trajectory, eliminates the residual stress field distortion that causes the distortion of the weak rigid part from the physical root, and improves the surface strengthening quality of the weak rigid thin-walled part. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a flow chart schematically showing a shot blasting equipment coordination control method for double-sided compensation processing in the present application; Figure 2 is a schematic diagram of real-time geometric feature monitoring data for the robot end; Figure 3 is a schematic diagram of a smooth performance coefficient curve and a control instruction curve; Figure 4 is a schematic diagram of pressure response hysteresis compensation effect; Figure 5 is an effective impact kinetic energy density distribution thermodynamic diagram under the prior art; Figure 6 is an effective impact kinetic energy density distribution thermodynamic diagram of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0023] The specific embodiments of the present application will be described in detail below with reference to the drawings.

[0024] The embodiment of the application discloses a shot blasting equipment coordinated control method for double-sided compensation machining, referring to Figure 1 , comprising steps S1 to S3: S1, determining the original relative attitude performance coefficient according to the real-time shot distance and the real-time incident angle of the robot, and performing sliding average filtering on the original relative attitude performance coefficient to obtain a smooth performance coefficient.

[0025] It should be noted that when the double robots mirror shot blast the weak rigid parts such as the aero-engine blades, the motion instructions sent by the control system to the robots and the pressure instructions sent to the shot blasting equipment are logically pursued to be synchronized, but due to the differences between the transmission path and the processing mechanism of the robot pose data obtained by the industrial field bus and the pressure sensor data obtained by the analog quantity acquisition card, there is often a millisecond-level timing deviation between them. At the same time, when the robot end follows the complex curved surface motion, for example, through the blade inlet and exhaust edge, the curvature of the workpiece surface will change suddenly, and the sudden change of the curvature will cause the calculated geometric features to jump sharply and frequently, and if the jumping geometric features are directly used for pressure control, it will cause the frequent action of the electrical proportional valve and the oscillation of the gas path system, affecting the machining quality. In addition, due to the asymmetric geometric characteristics of the blade, one side of which is the blade basin and the other side of which is the blade back, the physical attitude of the robot end relative to the workpiece surface is not the same and changes in real time when the left and right robots follow the curved surface motion.

[0026] Therefore, the application establishes a unified time reference axis, uses a ring buffer to cache the end pose data uploaded by the robot controller and the pressure data uploaded by the sensor with time stamping, and establishes independent data channels for the left and right robots, and all subsequent steps are independently executed in parallel for each side of the robot to realize precise cooperation under asymmetric working conditions.

[0027] Specifically, the system reads the timing-aligned robot end coordinates and workpiece three-dimensional model data in real time, calculates the current real-time shot distance and real-time incident angle, and the real-time incident angle is the included angle between the shot gun axis vector and the current point normal vector of the workpiece surface, and the included angle range is .

[0028] Figure 2 For the real-time geometric feature monitoring data of the robot end during the machining process, it can be seen that with the extension of the machining path, the geometric attitude of the robot is constantly fluctuating, especially in a specific section of the time axis, such as the 6-second to 8-second interval, the incident angle has a large mutation, indicating that the robot has passed the large curvature area of the blade edge.

[0029] Further, according to the real-time shot distance and the real-time incident angle, the original relative attitude performance coefficient is determined:

[0030] In the formula, express The original relative attitude efficiency coefficient at time; This represents the standard optimal spray distance set by the process, serving as a normalized baseline value. express Real-time spray distance of the robot; express The real-time angle of incidence at any given moment.

[0031] In the formula, Based on the principle of jet diffusion, this reflects the energy density dilution effect caused by the inverse square-proportional diffusion of the projectile jet cross-sectional area with respect to distance. This applies when the real-time jet distance... Greater than the standard optimal spray distance hour, A value less than 1 indicates a decrease in energy density; Based on the principle of momentum decomposition, this term reflects the vector attenuation of the normal effective impact momentum caused by oblique incidence, when the real-time incident angle... As the distance increases, the normal component decreases, and the energy transfer efficiency decreases; when the real-time injection distance... Larger and real-time incident angle When the value is larger, the original relative attitude effectiveness coefficient The smaller the value, the lower the energy transfer efficiency under the current geometric posture.

[0032] Furthermore, to prevent drastic changes in calculation results due to abrupt changes in workpiece surface curvature, a moving average filter is applied to the original relative attitude efficiency coefficients to obtain the final smooth efficiency coefficients used for control:

[0033] In the formula, express The smoothing efficiency coefficient at any given time; This indicates the window size for the moving average filter, which determines the degree of smoothing. The empirical value range is [5, 10]. In this embodiment, In other embodiments, the window size can be set to 5, depending on the severity of the curvature change on the workpiece surface. The more severe the curvature change, the larger the window size should be. Indicates the sampling interval; express The original relative attitude performance coefficients at time 1. Using a moving average filter, the original relative attitude performance coefficients can be filtered out. The high-frequency noise in the output control signal is smoothed to avoid mechanical oscillation or fatigue damage of the electric proportional valve caused by over-responding.

[0034] S2, calculate a theoretical compensation pressure according to the smoothing efficiency coefficient, perform physical boundary constraint on the theoretical compensation pressure, and generate a control instruction sent to the electric proportional valve.

[0035] It should be noted that the existing shot control mostly adopts a constant pressure mode, which ignores the sensitivity of the projectile beam energy density to the geometric posture, resulting in insufficient energy input under a non-standard posture, such as a long distance or an angle tilt, which causes the depth of the strengthening layer on the surface of the part to be uneven, and further causes the deformation of the part. Therefore, the feedforward compensation strategy based on the efficiency model is adopted, within a certain range, increasing the shot air pressure can increase the initial velocity and mass flow rate of the projectile, thereby compensating for the loss of energy flux caused by poor geometric posture, that is, when the smoothing efficiency coefficient decreases, the system actively increases the shot air pressure, and vice versa, to ensure that the energy density acting on the workpiece surface is constant.

[0036] Specifically, a theoretical compensation pressure is calculated according to the smoothing efficiency coefficient:

[0037] In the formula, represents the theoretical compensation pressure at the moment t; represents a reference shot pressure specified in a process specification; represents a compensation gain factor; represents the smoothing efficiency coefficient at the moment t;

[0038] In the formula, constitutes a nonlinear gain based on the reciprocal of the efficiency, when the smoothing efficiency coefficient is less than 1, there is energy loss, is positive, driving the theoretical compensation pressure to rise; the compensation gain factor is used to adjust the sensitivity to geometric errors, the empirical value range of is 0 to 1, a smaller value can be taken for a material with high work hardening sensitivity to prevent over-shooting, for example, when processing single crystal alloys, the compensation gain factor can be set to 0.3, and in other embodiments, the implementer can set the compensation gain factor according to the mechanical properties of the shot material.

[0039] It should be noted that, in order to prevent the calculated theoretical compensation pressure from exceeding the physical bearing capacity of the electric proportional valve or pipeline, causing equipment damage or alarm, the present application sets a physical boundary constraint on the theoretical compensation pressure. ​​

[0040] Specifically, the theoretical compensation pressure is physically bounded to generate a control instruction sent to the electric proportional valve:

[0041] Wherein, represents the control instruction at the moment; represents the theoretical compensation pressure at the moment; represents the lower limit of the preset safe working pressure; represents the upper limit of the preset safe working pressure. Through the limiting process, when the theoretical compensation pressure exceeds the safe range, the boundary value is forced to be output to prevent system oscillation or actuator overload caused by the theoretical compensation pressure exceeding the physical boundary, thereby protecting the electric proportional valve and the flexible pipeline system.

[0042] Figure 3 For the smooth efficiency coefficient curve and the control instruction curve diagram, it can be seen that the control instruction and the smooth efficiency coefficient are inversely related. When the smooth efficiency coefficient decreases, that is, the geometric posture deteriorates, the control instruction actively rises to compensate for energy.

[0043] S3, using the pressure sensor installed at the end of the spray gun to collect the actual pipeline pressure, calculating the deviation of the control instruction and the actual pipeline pressure, and introducing a hysteresis compensation term based on the gas path response time constant to correct the control instruction to obtain the final execution instruction, and sending the final execution instruction to the electric proportional valve to control the shot pressure.

[0044] It should be noted that in the actual physical system, the transmission of compressed air in the pipeline, the valve core action of the large flow valve, and the coil magnetization of the electric proportional valve all have physical delay, usually tens of milliseconds. If the control instruction is directly executed, the pressure change will always lag behind the pose change of the robot, causing misalignment compensation, that is, the pose of the robot has changed, but the pressure is still adapting to the pose at the last moment. Therefore, the present application introduces a hysteresis compensation mechanism based on sensor feedback, uses an integral algorithm to calculate the cumulative historical error, and dynamically corrects the current instruction to ensure that the pressure compensation action can accurately act on the corresponding track point.

[0045] Specifically, the actual pipeline pressure is collected by using the pressure sensor installed at the end of the spray gun, the deviation of the control instruction and the actual pipeline pressure is calculated, and a hysteresis compensation term is introduced to obtain the final execution instruction:

[0046] Wherein, represents the final execution instruction sent to the electric proportional valve at the moment; represents the control instruction at time t; represents a hysteresis compensation coefficient, used to adjust the correction strength of the historical error, the experience value range is [0.1, 0.5], in the embodiment, the hysteresis compensation coefficient is set to 0.4, in other embodiments, the implementer can set the hysteresis compensation coefficient according to the actual implementation situation , for example, when the gas path response is slow, the compensation coefficient can be appropriately increased, when the gas path response is fast, the compensation coefficient can be appropriately reduced; represents the gas path response time constant of the system, which is obtained by step response test during system initialization, representing the inherent physical delay of the gas path system from the instruction to the pressure build-up; represents the control instruction at time t; represents the control instruction at time t; represents the actual pipeline pressure fed back by the sensor at time t.

[0047] In the formula, the integral term calculates the average deviation of the control instruction and the actual pressure in the past time period, which reflects the hysteresis degree of the gas path response, and the average deviation multiplied by the hysteresis compensation coefficient is superimposed into the current control instruction, realizing the predictive compensation of the gas path hysteresis, thereby improving the dynamic following performance of the pressure control.

[0048] Preferably, the specific process of the step response test is: in the system empty state, a step instruction signal from zero pressure to the reference working pressure is sent to the electric proportional valve, and the pressure change curve at the end of the spray gun is recorded in real time by using a high-frequency pressure sensor; the time span required for the pressure to rise to 63.2% of the final steady-state pressure from the time when the step instruction is issued is defined as the gas path response time constant , wherein 63.2% is based on the theoretical response characteristic value of a first-order inertia system at time ; the test reflects the total physical hysteresis characteristics of the system including the electric proportional valve response, the pipeline charging delay and the large flow valve action delay.

[0049] Figure 4 is a schematic diagram of pressure response hysteresis compensation effect, it can be obviously observed that in order to offset the physical hysteresis of the gas path, the final execution instruction is obviously ahead of the control instruction in phase, and this pre-judgment control successfully drags the actual pipeline pressure to closely follow the control instruction, eliminating the hysteresis error.

[0050] ​Further, the final execution instructions of the two-sided robot are converted into voltage signals or current signals and synchronously sent to the electric proportional valve to realize real-time collaborative control of the shot pressure.

[0051] Figure 5 The effective impact kinetic energy density distribution thermograph under the prior art, Figure 6 The effective impact kinetic energy density distribution thermograph of the present application, the effective impact kinetic energy density refers to the total effective impact kinetic energy acting on the unit area of the workpiece surface per unit time, which can reflect the impact strength of the shot and the effect of surface strengthening during the shot blasting process, and the acquisition method is as follows: the actual pipeline pressure collected in real time is used as the initial energy intensity of the shot flow beam, the calculated smoothing efficiency coefficient is used as the geometric transmission efficiency, and the product of the initial energy intensity and the geometric transmission efficiency is calculated as the effective impact kinetic energy density actually acting on the workpiece surface. Figure 5 It is shown that under the constant pressure control of the prior art, there is a significant energy severe attenuation zone on the workpiece surface in the geometric mutation area, and this zebra-like uneven energy distribution is the direct cause of the deformation of the part. Figure 6 It is shown that after the adaptive compensation control of the present application is adopted, although the geometric posture on the machining path fluctuates sharply, through automatic pressure compensation, the effective impact kinetic energy density of the workpiece surface is always maintained at a uniform high energy level, and the residual stress field distortion leading to the distortion of the weak rigid part is eliminated from the physical root.

Claims

1. A method for coordinated control of shot peening equipment for double-sided compensation machining, characterized in that, Comprise: For the left and right robots, respectively based on the respective data channel to generate the corresponding final execution instruction, including: according to the real-time injection distance and real-time incident angle of the robot to determine the original relative attitude performance coefficient, the original relative attitude performance coefficient is filtered by sliding average, and the smooth performance coefficient is obtained; according to the smooth performance coefficient, the theoretical compensation pressure is calculated, the theoretical compensation pressure is physically constrained, and the control instruction is sent to the electric proportional valve; the actual pipeline pressure is collected by the pressure sensor installed at the end of the spray gun, the deviation between the control instruction and the actual pipeline pressure is calculated, and the hysteresis compensation term based on the gas path response time constant is introduced to modify the control instruction, and the final execution instruction is obtained; The final execution instruction is sent to the electric proportional valve to control the shot pressure.

2. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, Also include: A unified time reference axis is established, and the end pose data uploaded by the robot controller and the pressure data uploaded by the sensor are cached and time-aligned, the end pose data includes the real-time injection distance and real-time incident angle of the robot, and the pressure data is the actual pipeline pressure collected by the pressure sensor installed at the end of the spray gun.

3. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized in that, The original relative attitude performance coefficient satisfies the expression: ； In the formula, represents the original relative attitude performance coefficient at the moment; represents the standard optimal spraying distance set by the process; represents the real-time spraying distance of the robot at the moment; represents the real-time incident angle at the moment.

4. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, The smooth performance coefficient satisfies the expression: ； In the formula, represents the smoothed performance coefficient at the time instant; represents the window size of the moving average filter; represents the sampling interval; represents the original relative attitude performance coefficient at the time instant.

5. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, The theoretical compensation pressure satisfies the expression: ； wherein represents the theoretical compensation pressure at the time instant; represents the reference shot pressure as specified by the process recipe; represents the compensation gain factor; represents the smoothed performance coefficient at the time instant.

6. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, The physical boundary constraint on the theoretical compensation pressure to generate the control instruction sent to the electric proportional valve, including: In response to the theoretical compensation pressure being less than the lower limit of the safe working pressure, the control instruction is set to the lower limit of the safe working pressure; in response to the theoretical compensation pressure being greater than or equal to the lower limit of the safe working pressure and less than or equal to the upper limit of the safe working pressure, the control instruction is set to the theoretical compensation pressure; in response to the theoretical compensation pressure being greater than the upper limit of the safe working pressure, the control instruction is set to the upper limit of the safe working pressure.

7. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, The final execution instruction satisfies the expression: ； wherein represents final execution command sent to the electric proportional valve at time t; represents control command at time t; represents a hysteresis compensation coefficient; represents a gas passage response time constant of the system; represents a control command at time t in the integral zone; represents a control command at time t in the integral zone; represents a control command at time t in the integral zone; represents an actual pipe pressure fed back by the sensor at time t.

8. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to claim 1 or 7, characterized in that, The method for obtaining the gas path response time constant is: Under the condition of system no-load, a step instruction signal from zero pressure to reference working pressure is sent to the electric proportional valve; the pressure change curve at the end of the spray gun is recorded in real time by using a high-frequency pressure sensor; the time span required for the pressure to rise from the time when the step instruction is issued to 63.2% of the final steady-state pressure is taken as the gas path response time constant of the system.

9. The coordinated control method of a shot peening apparatus for double-sided compensation machining according to any one of claims 1 to 3, characterized in that, The real-time incident angle is the included angle between the spray gun axis vector and the current point normal vector of the workpiece surface.

10. The coordinated control method for a shot peening apparatus for double-sided compensation machining according to claim 1, characterized by, The final execution instruction is sent to the electric proportional valve to control the shot pressure, including: The final execution instructions of the left and right robots are converted into voltage signals or current signals and sent to the corresponding electric proportional valves.

Images