Active floating polishing unit and polishing method

Abstract

This invention belongs to the field of grinding technology; specifically, it discloses an active floating grinding unit and grinding method, including an upper connecting flange connected to a robotic arm for transmitting the robotic arm's motion commands and power; a lower telescopic flange connected to a grinding mechanism for performing grinding operations; a housing between the upper connecting flange and the lower telescopic flange, with a low-friction sliding mechanism inside the housing providing buoyancy for force output during grinding; a floating joint connected below the low-friction sliding mechanism, which is connected to the lower telescopic flange to eliminate jamming of the low-friction cylinder piston rod caused by manufacturing errors; a displacement detection unit on one side of the low-friction sliding mechanism, which provides feedback on the movement distance of the low-friction sliding mechanism; it can automatically adjust grinding parameters according to the material, shape, and surface condition of different workpieces, thus being suitable for grinding workpieces of various complex shapes and improving processing quality.

Description

Technical Field

[0001] This invention belongs to the field of polishing technology, and particularly relates to an active floating polishing unit and polishing method. Background Technology

[0002] Traditional grinding methods present numerous problems in current grinding operations. Manual grinding relies heavily on labor, is physically demanding, and prolonged repetitive work easily leads to worker fatigue, affecting the stability of grinding quality and making it difficult to guarantee consistent grinding pressure and precise grinding paths. Furthermore, the dust and noise generated during grinding pose significant health risks to workers. In addition, for workpieces with complex shapes and structures, the efficiency and precision of manual grinding are insufficient to meet the demands of modern manufacturing.

[0003] While some automated grinding equipment has improved efficiency to a certain extent, it falls short in terms of constant force control and adapting to workpiece surface irregularities. It cannot automatically adjust grinding parameters according to the actual conditions of the workpiece, resulting in inconsistent grinding quality, failing to meet the requirements of high-precision machining, and also causing energy waste and increased scrap. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an active floating grinding unit and grinding method suitable for complex workpieces. Due to the unit's self-adaptability, it can automatically adjust grinding parameters according to the material, shape, and surface condition of different workpieces, making it applicable to grinding workpieces of various complex shapes. Improved processing quality: The constant-force floating grinding unit can achieve a constant grinding force and automatically adjust the position of the grinding head, effectively improving the surface quality and precision of the workpiece and meeting the needs of high-precision machining. Energy saving and environmental protection: The constant-force floating grinding unit can reduce energy consumption and waste generation by precisely controlling the grinding force and position, aligning with the development trend of energy conservation and environmental protection, and at least solving one of the problems in the background technology.

[0005] This invention provides the following technical solution:

[0006] The active floating grinding unit includes an upper connecting flange, which is connected to the robotic arm to transmit the robotic arm's motion commands and power.

[0007] The lower telescopic flange is connected to a grinding mechanism, which is used to perform grinding operations. The grinding mechanism can be configured with different types of grinding tools according to different needs, and can be connected to angle grinders, air grinders, straight grinders, and grinding heads.

[0008] A housing is provided between the upper connecting flange and the lower telescopic flange. A low-friction sliding mechanism is provided inside the housing. The low-friction sliding mechanism provides floating force for the output of force during the grinding process.

[0009] A floating joint is connected below the low-friction sliding mechanism. The floating joint is used to eliminate the jamming of the piston rod extension and retraction of the low-friction cylinder caused by manufacturing errors.

[0010] A displacement detection unit is provided on one side of the low-friction sliding mechanism, and the displacement detection unit provides feedback on the moving distance of the low-friction sliding mechanism;

[0011] The dustproof sealing cloth is equipped with clamps and is connected to the housing through the clamps. The lower end is connected to the lower telescopic flange through the clamps. The dustproof sealing cloth isolates the internal components.

[0012] Preferably, the low-friction sliding mechanism is a low-friction cylinder, which is connected to a pressure regulating valve and a reversing valve. Limiting blocks are provided on both sides of the low-friction cylinder, and the limiting blocks are connected to the housing. The low-friction cylinder is a bidirectional cylinder, which can apply pressure in both directions. The pressure regulating valve adjusts the pressure entering the low-friction cylinder and controls the magnitude of the output force.

[0013] Preferably, the displacement detection unit is a displacement sensor, which is used to detect the extension length of the low-friction cylinder and provide feedback for the pressure regulating valve to compensate for the output and release of pressure. The displacement sensor monitors the displacement of the low-friction cylinder in real time and transmits it back to the host computer through analog signals, which are then fed back to the pressure regulating valve to adjust the pressure in real time. The reversing valve is a two-position solenoid valve, which is used for the reversing operation of the low-friction cylinder to achieve constant push and pull force of the low-friction cylinder.

[0014] Preferably, one side of the low-friction sliding mechanism is provided with a tilt angle detection unit. The tilt angle detection unit adopts an angle sensor. The angle sensor calculates the gravitational component applied to the workpiece based on the current angle of the floating grinding mechanism, and compares and calculates it with the set force to achieve a constant force applied to the workpiece in the 360-degree direction.

[0015] Preferably, the low-friction sliding mechanism is equipped with a breathing silencer, which is used to compensate for the air pressure changes generated inside and outside the low-friction sliding mechanism during floating and to isolate air impurities.

[0016] Preferably, it also includes a data transmission interface, which connects to the pressure regulating valve, the reversing valve, the displacement detection unit, and the tilt detection unit; the data transmission interface inputs and outputs displacement, angle, and air pressure data signals to the host computer.

[0017] Preferably, a polishing method based on an active floating polishing unit, using this floating polishing unit, includes the following steps:

[0018] S1: Stroke calibration. Start the equipment and slowly reduce the stroke of the floating unit cylinder to the minimum value. Set and record the corresponding analog quantity through the equipment control system. Then, reduce the stroke of the low-friction cylinder to the maximum value and set and record the corresponding analog quantity to complete the stroke calibration.

[0019] S2: Angle calibration. Place the floating connector horizontally, read the analog value of the angle sensor at this time and record it as AngleMax; then invert the floating connector horizontally, read the analog value of the angle sensor and record it as AngleMin to complete the angle calibration.

[0020] S3: Weight calibration. Following the weight calibration algorithm steps, the air pressure is gradually adjusted. The budget pressure is recorded each time the low-friction cylinder stroke exceeds a specific length L. The coarse budget air pressure and fine budget air pressure of the load are calculated, and the tool weight G is finally accurately calculated.

[0021] S4: Constant force output. Before the grinding operation, the constant grinding force F applied to the workpiece is set on the control panel of the host computer according to the material, surface condition and other factors of the workpiece. During the grinding process, the angle θ between the axis of the low friction cylinder and the horizontal plane is read in real time. The real-time output pressure of the cylinder is calculated according to the constant force output algorithm. By controlling the air pressure of the proportional valve, the workpiece is always subjected to a constant grinding force F during the grinding process.

[0022] S5: End force compensation. During the movement of the low-friction cylinder, the system monitors the changes in cylinder stroke and current status in real time, determines the direction of friction force according to the end force compensation algorithm, and compensates the output force accordingly to ensure that the output force at the end of the floating joint is constant and improves the grinding quality.

[0023] Preferably, in step S4, the low-friction cylinder operates as follows: a) Gas enters, and the pressure is controlled by a pressure regulating valve; b) If a downward thrust is required, the solenoid valve is not activated, and air pressure is introduced into the rodless chamber of the low-friction cylinder to extend the cylinder downward, providing downward pressure; c) If an upward pull is required, the solenoid valve reverses its operation, and air pressure is introduced into the rod chamber of the low-friction cylinder to pull the cylinder upward, providing upward pull; d) The displacement of the low-friction cylinder is monitored in real time by a displacement sensor, and the analog signal is transmitted back to the host computer to feed back to the pressure regulating valve for real-time pressure adjustment.

[0024] Preferably, the pressure regulating valve is set with the required force on the host computer control panel. After the required force is set, the system is vented, and the venting is greater than the required force setting. The output pressure of the pressure regulating valve is adjusted by the program in the host computer. The system will automatically eliminate the influence of the grinding tool, friction, and its own weight, so that the force when the grinding tool contacts the workpiece is constant and is the required force.

[0025] Preferably, when this technical solution is used, it is used in cooperation with a robotic arm and is connected to the robotic arm through an upper connecting flange.

[0026] Preferably, the specific process of stroke calibration is as follows:

[0027] Press the stroke of the floating unit cylinder to the minimum value, and set it as the analog quantity corresponding to the minimum stroke.

[0028] Press the stroke of the floating unit cylinder to the maximum value, and set it as the analog quantity corresponding to the maximum stroke.

[0029] The specific process of angle calibration is as follows: <000006!>

[0030] Place the floating unit horizontally and obtain the maximum analog quantity AngleMax of the angle sensor; <CO000064>Invert the floating unit horizontally and obtain the minimum analog quantity AngleMin of the angle sensor.

[0032] The specific process of weight calibration is as follows: [[ID=2!]]

[0033] Increase the air pressure with a pressure change step of Step1. When the cylinder stroke exceeds L (unit: mm), stop and record the estimated pressure pressure1 at this time;

[0034] Decrease the air pressure with a pressure change step of Step1. When the cylinder stroke exceeds L (unit: mm), stop and record the estimated pressure pressure2 at this time; [[ID=Z9]]

[0035] The estimated air pressure for the load pressureLoad = (pressure1 + pressure2) / 2;

[0036] Apply the estimated air pressure pressure1 to the floating unit, and the cylinder moves to the position at the end of Step 1. At this time, the floating unit is in a suspended state;

[0037] Replace the suspended air pressure pressure3 = the estimated air pressure for the load pressureLoad.

[0038] Decrease the air pressure with a pressure change step of Step2 (Step2 < Step1). When the cylinder stroke exceeds (unit: mm), stop and record the estimated air pressure pressure4 at this time; [[ID=A0]]

[0039] Increase the air pressure with a pressure change step of Step2 (Step2 < Step1). When the cylinder stroke exceeds L (unit: mm), stop and record the estimated air pressure pressure5 at this time;

[0040] The estimated air pressure for the load pressure6 = (pressure4 + pressure5) / 2; [[ID=4!]]

[0041] The weight of the tool is G = pressure6 / S, where S is the area of ​​the force.

[0042] The specific process of constant force output:

[0043] If the constant grinding force applied to the workpiece is set to F, and the real-time angle between the cylinder axis and the horizontal plane is read as θ, then the real-time component of gravity G in the direction of the cylinder axis is F1=Gxsinθ.

[0044] The calculation of the cylinder's real-time output pressure being greater than 0 involves three cases:

[0045] If the floating unit is facing upwards, i.e., θ is greater than 0, then the real-time output is f = F + F1, and the cylinder is in the extended state.

[0046] If the floating unit is facing downwards, i.e., θ is less than 0 and F is less than F1, then the real-time output force f = F1 - F, and the cylinder is in the extension / retraction state.

[0047] If the floating unit is facing downwards (θ is less than 0 and F is greater than F1), then the real-time output force is f = F - F1, and the cylinder is in the extended state.

[0048] The calculation of a cylinder's real-time output pressure being less than 0 involves three cases:

[0049] Set the absolute value of the real-time output pressure of the cylinder to F2.

[0050] If the floating unit is facing upwards, i.e., θ is greater than 0 and F2 is less than F1, then the real-time output is f = F1 - F2, and the cylinder is in the extended state.

[0051] If the floating unit is facing upwards, i.e., θ is greater than 0 and F2 is greater than F1, then the real-time output is f = F2 - F1, and the cylinder is in a compressed state.

[0052] If the floating unit is facing downwards, i.e., θ is less than 0, then the real-time output is f = F2 + F1, and the cylinder is in the extended state.

[0053] During the grinding process, the output force is calculated in real time based on the change of the angle between the floating unit and the horizontal plane. By controlling the air pressure of the proportional valve, the grinding force received by the workpiece during the grinding process is always F.

[0054] The specific process of end-effector force compensation:

[0055] Friction is generated during the movement of the cylinder. In order to ensure that the output force at the end of the floating unit is constant, the output needs to be compensated to eliminate the friction.

[0056] This method determines the direction of friction based on the change in cylinder stroke and compensates for the output force according to the current state of the cylinder. The friction force is set as F2, and the real-time output force is f. Based on the cylinder state, the following four cases are considered:

[0057] When the constant grinding force F is greater than 0, the cylinder is in the extended state, the stroke increases, and the real-time output force is f = f + F2.

[0058] When the constant grinding force F is greater than 0, the cylinder is in the extended state, the stroke is reduced, and the real-time output force is f = f - F2.

[0059] When the constant grinding force F is greater than 0, the cylinder is in a compressed state, the stroke increases, and the real-time output force is f = f - F2.

[0060] When the constant grinding force F is greater than 0, the cylinder is in a compressed state, the stroke becomes smaller, and the real-time output force f = f + F2;

[0061] When the grinding constant force F is less than 0, the cylinder is in the extended state, the stroke increases, and the real-time output force f = f + F2;

[0062] When the constant grinding force F is less than 0, the cylinder is in the extended state, the stroke becomes smaller, and the real-time output force f = f - F2;

[0063] When the constant grinding force F is less than 0, the cylinder is in the retracted state and the stroke increases, so the real-time output force f = f - F2;

[0064] When the grinding constant force F is less than 0, the cylinder is in the retracted state, the stroke increases, and the real-time output force f = f + F2.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] This invention relates to an active floating grinding unit and grinding method, with the following technical performance characteristics: Constant force control: The unit maintains a constant force during the grinding process, ensuring consistent grinding pressure and thus improving grinding quality. Floating system: The floating system allows the grinding head to move freely within a certain range to adapt to the irregularities of the workpiece surface. High-precision positioning: The robot itself has high-precision positioning capabilities, accurately controlling the position and path of the grinding head to ensure the repeatability and consistency of the grinding work. Improved product quality: Through constant grinding force and high-precision control, the uniformity and repeatability of the grinding process are ensured, significantly improving the quality of product surface treatment. Reduced labor costs: Automated grinding reduces reliance on manual operation, especially in long-term, repetitive grinding operations, significantly reducing labor costs. Improved working environment: The robotic grinding unit can operate in enclosed or semi-enclosed environments, effectively reducing the impact of dust and noise, improving the working environment, and reducing health risks to workers.

[0067] Adaptable to complex workpieces: Due to its self-adaptive nature, the unit can automatically adjust grinding parameters according to the material, shape, and surface condition of different workpieces, making it suitable for grinding workpieces of various complex shapes. Improved processing quality: The constant force floating grinding unit can achieve constant grinding force and automatically adjust the position of the grinding head, effectively improving the surface quality and precision of the workpiece and meeting the needs of high-precision machining. Energy-saving and environmentally friendly: The constant force floating grinding unit can reduce energy consumption and waste generation by precisely controlling the grinding force and position, which is in line with the development trend of energy conservation and environmental protection. Attached Figure Description

[0068] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0069] Figure 1 This is a schematic diagram of the overall structure of the polishing unit of the present invention.

[0070] Figure 2 This is a schematic diagram of the cross-sectional structure of the present invention.

[0071] Figure 3 This is a schematic diagram of the longitudinal section structure of the present invention. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0073] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0074] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention. Example

[0075] refer to Figure 1-3 The active floating grinding unit includes an upper connecting flange 1, which is connected to the robotic arm and is used to transmit the motion commands and power of the robotic arm.

[0076] The lower telescopic flange 2 is connected to a grinding mechanism, which is used to perform grinding operations. The grinding mechanism can be configured with different types of grinding tools according to different needs, and can be connected to angle grinders, air grinders, straight grinders, and grinding heads by bolts.

[0077] A housing is provided between the upper connecting flange 1 and the lower telescopic flange 2. A low-friction sliding mechanism 5 is provided inside the housing. The low-friction sliding mechanism 5 provides floating force for the output of force during the grinding process. A floating joint 9 is connected below the low-friction sliding mechanism 5. The floating joint 9 is used to eliminate the jamming of the piston rod of the low-friction cylinder caused by manufacturing errors. A displacement detection unit 4 is provided on one side of the low-friction sliding mechanism 5. The displacement detection unit 4 provides feedback on the movement distance of the low-friction sliding mechanism 5.

[0078] The dustproof sealing cloth 12 is equipped with a clamp 13. The dustproof sealing cloth 12 is connected to the housing through the clamp 13, and the lower end is connected to the lower telescopic flange 2 through the clamp 13. The dustproof sealing cloth 12 isolates the internal components.

[0079] The low-friction sliding mechanism 5 is a low-friction cylinder. The low-friction cylinder is connected to the pressure regulating valve 3 and the reversing valve 8. Limiting blocks 6 are provided on both sides of the low-friction cylinder. The limiting blocks 6 are connected to the housing. The low-friction cylinder is a bidirectional cylinder. The low-friction cylinder can apply pressure in both directions. The pressure regulating valve 3 regulates the pressure entering the low-friction cylinder and controls the magnitude of the output force.

[0080] The displacement detection unit 4 is a displacement sensor, which is used to detect the extension length of the low-friction cylinder and provide feedback. This feedback is used by the pressure regulating valve 3 to compensate for the output and release of pressure. The displacement sensor monitors the displacement of the low-friction cylinder in real time and transmits it back to the host computer through analog signals, which then feeds back to the pressure regulating valve 3 to adjust the pressure in real time. The reversing valve 8 is a two-position solenoid valve, which is used for the reversing operation of the low-friction cylinder to achieve constant push and pull force of the low-friction cylinder.

[0081] One side of the low-friction sliding mechanism 5 is equipped with a tilt angle detection unit 7. The tilt angle detection unit 7 uses an angle sensor. Based on the current angle of the floating grinding mechanism, the angle sensor calculates the gravitational component force applied to the workpiece and compares it with a set force to achieve a constant force applied to the workpiece in a 360-degree direction. The low-friction sliding mechanism 5 is equipped with a breathing silencer 11, which is used to compensate for the air pressure changes generated inside and outside the low-friction sliding mechanism 5 during floating and to isolate air impurities.

[0082] It also includes a data transmission interface 10, which connects to the pressure regulating valve 3, the reversing valve 8, the displacement detection unit 4, and the tilt detection unit 7; the data transmission interface 10 inputs and outputs displacement, angle, and air pressure data signals to the host computer.

[0083] As one possible implementation method, a polishing method based on an active floating polishing unit includes the following steps:

[0084] S1: Stroke calibration. Start the equipment and slowly reduce the stroke of the floating unit cylinder to the minimum value. Set and record the corresponding analog quantity through the equipment control system. Then, reduce the stroke of the low-friction cylinder to the maximum value and set and record the corresponding analog quantity to complete the stroke calibration.

[0085] S2: Angle calibration. Place the floating connector horizontally, read the analog value of the angle sensor at this time and record it as AngleMax; then invert the floating connector horizontally, read the analog value of the angle sensor and record it as AngleMin to complete the angle calibration.

[0086] S3: Weight calibration. Following the weight calibration algorithm steps, the air pressure is gradually adjusted. The budget pressure is recorded each time the low-friction cylinder stroke exceeds a specific length L. The coarse budget air pressure and fine budget air pressure of the load are calculated, and the tool weight G is finally accurately calculated.

[0087] S4: Constant force output. Before the grinding operation, the constant grinding force F applied to the workpiece is set on the control panel of the host computer according to the material, surface condition and other factors of the workpiece. During the grinding process, the angle θ between the axis of the low friction cylinder and the horizontal plane is read in real time. The real-time output pressure of the cylinder is calculated according to the constant force output algorithm. By controlling the air pressure of the proportional valve, the workpiece is always subjected to a constant grinding force F during the grinding process.

[0088] S5: End force compensation. During the movement of the low-friction cylinder, the system monitors the changes in cylinder stroke and current status in real time, determines the direction of friction force according to the end force compensation algorithm, and compensates the output force accordingly to ensure that the output force at the end of the floating joint is constant and improves the grinding quality.

[0089] In step S4, the low-friction cylinder operates as follows: a) Gas enters, and the pressure is controlled by the pressure regulating valve; b) If a downward thrust is required, the solenoid valve is not activated, and air pressure is supplied to the rodless chamber of the low-friction cylinder, causing the cylinder to extend downward and providing downward pressure; c) If an upward pull is required, the solenoid valve reverses its operation, and air pressure is supplied to the rod chamber of the low-friction cylinder, causing the cylinder to pull upward and providing upward pull; d) The displacement of the low-friction cylinder is monitored in real time by a displacement sensor, and the analog signal is transmitted back to the host computer, which then feeds back to the pressure regulating valve to adjust the pressure in real time.

[0090] The pressure regulating valve is set with the required force on the host computer control panel. After the required force is set, the system is vented, and the venting is greater than the required force setting. The output pressure of the pressure regulating valve is adjusted by the program in the host computer. The system will automatically eliminate the influence of the grinding tool, friction, and its own weight, so that the force when the grinding tool contacts the workpiece is constant and is the required force.

[0091] When using this technical solution, it is used in conjunction with a robotic arm and is connected to the robotic arm via the upper connecting flange.

[0092] This technical solution employs an adaptive adjustment mechanism at the hardware level: the active floating grinding unit utilizes a low-friction cylinder and a floating joint to achieve physical self-adaptation. The low-friction cylinder provides stable floating force, and when the workpiece surface has irregularities such as unevenness, the floating joint eliminates processing errors, allowing the grinding mechanism to move freely within a certain range and automatically conform to the workpiece surface, ensuring a smooth grinding process. For example, in the scenario of grinding body weld seams, the variations in weld seam height are maintained by the cooperation of the floating joint and the cylinder, ensuring that the grinding tool always maintains appropriate contact with the weld seam surface, thus maintaining grinding stability.

[0093] The sensor-feedback-based parameter adjustment scheme: The unit is equipped with multiple sensors. A displacement sensor monitors the cylinder extension and feeds the signal back to the pressure proportional valve for real-time pressure control. Angle sensors calculate the angle of the floating grinding mechanism, determining the gravitational component applied to the workpiece and comparing it with the set force to ensure a constant grinding force across 360 degrees. During actual grinding, if the workpiece surface is tilted, the angle sensor detects the angle change, and the system adjusts the pressure proportional valve accordingly, altering the cylinder output force to compensate for the grinding force deviation caused by the angle change.

[0094] Software algorithms enable precise parameter adjustments: The axial floating unit grinding software algorithm encompasses functions such as stroke, angle, and weight calibration. Stroke calibration determines the analog quantities corresponding to the minimum and maximum cylinder strokes, providing a foundation for precise stroke control; angle calibration obtains the maximum and minimum analog values ​​of the angle sensor when the cylinder is horizontally placed and inverted, calibrating angle measurements; weight calibration accurately calculates the tool's gravity, providing accurate parameters for constant force output calculation. In the constant force output stage, based on the real-time angle between the cylinder axis and the horizontal plane and the set grinding constant force, the real-time output pressure of the cylinder is calculated under various conditions. For example, when the floating unit is facing upwards and the real-time angle is θ, the component of gravity in the cylinder axis direction is F1=Gsinθ. If the set grinding constant force is F, then the real-time output force f=F+F1 (cylinder extended state). By controlling the proportional valve air pressure, a constant grinding force is achieved. Regarding end-effector force compensation, the direction of friction is determined based on changes in cylinder stroke and the current state, compensating for the output force to ensure stable grinding force.

[0095] In the specific grinding process, the frequency of grinding parameter adjustment is determined by taking into account factors such as workpiece characteristics, grinding process requirements, and equipment performance, in order to ensure grinding quality, efficiency, and stable equipment operation.

[0096] 1. Based on the workpiece surface condition: If the workpiece surface has significant variations in flatness, such as obvious undulations at the weld seam of a welded part, the grinding mechanism experiences drastic force changes when contacting different areas, requiring frequent adjustments to grinding parameters. A displacement sensor monitors changes in cylinder extension; if it exceeds the set range, the system responds quickly, adjusting the air pressure via a pressure proportional valve to change the cylinder output force, allowing the grinding mechanism to adapt to surface changes and ensuring constant grinding pressure. This process may involve adjustments several times per second or even more. If the workpiece surface is relatively flat, the parameter adjustment frequency can be significantly reduced. In some high-precision flat surface grinding scenarios, fine-tuning of parameters may only be needed every few seconds or tens of seconds.

[0097] 2. Grinding Stage: In the initial stage of grinding, the workpiece has a large amount of material to remove, requiring relatively stable grinding force and low parameter adjustment frequency. As grinding nears completion, to achieve high-precision surface quality, fine control of grinding force and position is necessary, increasing the adjustment frequency. In the grinding of optical lenses with extremely high precision requirements, near the polishing stage, parameters may need to be adjusted every few millimeters of grinding stroke to ensure the flatness and smoothness of the lens surface.

[0098] 3. Equipment Response Speed: The accuracy of sensors, data transmission speed, and the processing speed of control algorithms all affect the adjustment frequency. High-precision, fast-response sensors can accurately collect data in real time, and advanced algorithms can quickly process and issue adjustment commands, enabling the equipment to adjust parameters frequently. If the equipment response is slow, frequent adjustments may lead to over-correction of parameters, affecting the grinding quality. In this case, the adjustment frequency needs to be reduced to ensure that the equipment responds stably with each adjustment. For example, some early automated grinding equipment typically had a lower adjustment frequency due to hardware performance limitations.

[0099] 4. Process Stability: Stable grinding processes allow for relatively low-frequency adjustments, while parameter-sensitive processes require high-frequency adjustments. In traditional metal grinding processes, parameter fluctuations within a certain range have a relatively small impact on the final quality, allowing for low adjustment frequencies. However, in grinding new composite materials, even minor parameter changes can affect the material's structural integrity. To ensure process stability, grinding parameters need to be adjusted frequently based on real-time monitoring data. Currently, the given document does not directly mention how to determine the frequency of grinding parameter adjustments. However, based on the working principle and related technologies of active floating grinding units, the method for determining this frequency can be analyzed from the following aspects:

[0100] The grinding unit is equipped with displacement and angle sensors, which continuously collect data such as the workpiece surface condition and the position and angle of the grinding tool. The sensor feedback frequency directly affects the adjustment frequency of grinding parameters. A high sensor feedback frequency allows for more timely detection of minute changes on the workpiece surface, thus increasing the frequency of grinding parameter adjustments and ensuring grinding accuracy and quality. Conversely, a low sensor feedback frequency results in a lower adjustment frequency, potentially leading to insufficient responsiveness to changes in the workpiece surface during grinding.

[0101] Workpiece surface complexity: When a workpiece surface has many undulations, curvature variations, or irregular shapes, the contact between the grinding tool and the workpiece will frequently change during the grinding process. In this case, to ensure constant grinding force and stable grinding quality, grinding parameters need to be adjusted more frequently, resulting in a higher adjustment frequency. For example, when grinding molds with complex textures, high-frequency parameter adjustments are required.

[0102] For simple surfaces: If the workpiece surface is relatively flat and the contact state between the grinding tool and the workpiece changes little, then there is no need to adjust the grinding parameters too frequently, and the adjustment frequency can be appropriately reduced. For example, when grinding flat plates, the adjustment frequency can be lower than that for complex molds.

[0103] Grinding processes require high precision: For workpieces with extremely high surface quality requirements, such as aerospace components and precision instrument parts, even minute deviations in grinding parameters can affect the workpiece's performance and quality. To meet these high-precision grinding requirements, grinding parameters need to be monitored and adjusted in real time, resulting in a relatively high adjustment frequency.

[0104] General precision requirements: For some workpieces where surface quality requirements are not particularly stringent, such as the rough grinding process of ordinary mechanical parts, the adjustment frequency can be appropriately reduced to improve grinding efficiency.

[0105] The system response speed, the processing speed of the grinding unit's control system to sensor feedback signals, and the response speed of the actuators (such as pressure proportional valves) also affect the adjustment frequency. If the system response speed is fast and can quickly adjust the grinding parameters based on sensor feedback, then the adjustment frequency can be increased; conversely, if the system response speed is slow, an excessively high adjustment frequency may cause the system to fail to respond in time, thus affecting the grinding effect. In this case, the adjustment frequency needs to be appropriately reduced.

[0106] As one possible implementation method, the specific process of stroke calibration is as follows:

[0107] When the stroke of the floating unit cylinder is reduced to the minimum value, it is set as the analog quantity corresponding to the minimum stroke.

[0108] When the stroke of the floating unit cylinder reaches its maximum value, set it as the analog quantity corresponding to the maximum stroke.

[0109] Specific process of angle calibration:

[0110] The floating unit is placed horizontally to obtain the maximum analog value AngleMax from the angle sensor.

[0111] The floating unit is horizontally inverted to obtain the minimum value of the analog signal from the angle sensor, AngleMin.

[0112] The specific process of weight calibration:

[0113] Increase the air pressure, with a pressure change step size Step1. Stop when the cylinder stroke exceeds L (in mm). Record the estimated pressure at this point, pressure1.

[0114] Decrease the air pressure, with a pressure change step size Step1. Stop when the cylinder stroke exceeds L (in mm). Record the estimated pressure at this time, pressure2.

[0115] Coarse budget air pressure of load pressureLoad = (pressure1 + pressure2) / 2;

[0116] Give the floating unit a budget air pressure of pressure1, and the cylinder moves to the end position of step 1. At this time, the floating unit is in a suspended state;

[0117] Replace the suspended air pressure pressure3 = the coarse budget air pressure of load pressureLoad.

[0118] Reduce the air pressure, with an air pressure change step of Step2 (Step₂ < Step₁). Stop when the cylinder stroke exceeds (unit: mm). Record the budget air pressure pressure4 at this time;

[0119] Increase the air pressure, with an air pressure change step of Step2 (Step₂ < Step₁). Stop when the cylinder stroke exceeds L (unit: mm). Record the budget air pressure pressure5 at this time; <000***Fine budget air pressure of load pressure6 = (pressure4 + pressure5) / 2;

[0121] Tool gravity G = pressure6 / S, where S is the acting force area. <000***Specific process of constant force output:

[0123] Set the constant grinding force applied to the workpiece as F, and read the real-time angle between the cylinder axis and the horizontal plane as θ. Then the real-time component force of the gravity G in the direction of the cylinder axis is F1 = G × sinθ.<000***<000***Calculation of the cylinder's real-time output pressure greater than 0 is divided into three cases: <000***If the floating unit faces upward, that is, θ > 0, the real-time output f = F + F1, and the cylinder is in the extended state; <000***If the floating unit faces downward, that is, θ < 0 and F < F1, the real-time output force f = F1 - F, and the cylinder is in the telescopic state; <000***If the floating unit faces downward, that is, θ < 0 and F > F1, the real-time output force f = F - F1, and the cylinder is in the extended state. <000***Calculation of the cylinder's real-time output pressure less than 0 is divided into three cases: <000***Set the absolute value of the cylinder's real-time output pressure as F2. <000***If the floating unit is facing upwards, i.e., θ is greater than 0 and F2 is less than F1, then the real-time output is f = F1 - F2, and the cylinder is in the extended state.

[0131] If the floating unit is facing upwards, i.e., θ is greater than 0 and F2 is greater than F1, then the real-time output is f = F2 - F1, and the cylinder is in a compressed state.

[0132] If the floating unit is facing downwards, i.e., θ is less than 0, then the real-time output is f = F2 + F1, and the cylinder is in the extended state.

[0133] During the grinding process, the output force is calculated in real time based on the change of the angle between the floating unit and the horizontal plane. By controlling the air pressure of the proportional valve, the grinding force received by the workpiece during the grinding process is always F.

[0134] The specific process of end-effector force compensation:

[0135] Friction is generated during the movement of the cylinder. In order to ensure that the output force at the end of the floating unit is constant, the output needs to be compensated to eliminate the friction.

[0136] This method determines the direction of friction based on the change in cylinder stroke and compensates for the output force according to the current state of the cylinder. The friction force is set as F2, and the real-time output force is f. Based on the cylinder state, the following four cases are considered:

[0137] When the constant grinding force F is greater than 0, the cylinder is in the extended state, the stroke increases, and the real-time output force is f = f + F2.

[0138] When the constant grinding force F is greater than 0, the cylinder is in the extended state, the stroke is reduced, and the real-time output force is f = f - F2.

[0139] When the constant grinding force F is greater than 0, the cylinder is in a compressed state, the stroke increases, and the real-time output force is f = f - F2.

[0140] When the constant grinding force F is greater than 0, the cylinder is in a compressed state, the stroke becomes smaller, and the real-time output force f = f + F2;

[0141] When the grinding constant force F is less than 0, the cylinder is in the extended state, the stroke increases, and the real-time output force f = f + F2;

[0142] When the constant grinding force F is less than 0, the cylinder is in the extended state, the stroke becomes smaller, and the real-time output force f = f - F2;

[0143] When the constant grinding force F is less than 0, the cylinder is in the retracted state and the stroke increases, so the real-time output force f = f - F2;

[0144] When the grinding constant force F is less than 0, the cylinder is in the retracted state, the stroke increases, and the real-time output force f = f + F2.

[0145] Other technical solutions not described in detail in this invention are all existing technologies in the field and will not be elaborated here.

[0146] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations; any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An active floating polishing unit, characterized in that, It includes an upper connecting flange (1), which is connected to the robotic arm and is used to transmit the motion commands and power of the robotic arm; The lower telescopic flange (2) is connected to a grinding mechanism, which is used to perform grinding operations. A housing is provided between the upper connecting flange (1) and the lower telescopic flange (2), and a low-friction sliding mechanism (5) is provided inside the housing. The low-friction sliding mechanism (5) provides floating force for the output of force during the grinding process. The low-friction sliding mechanism (5) is connected to a floating joint (9) below. The floating joint (9) is used to eliminate the jamming of the piston rod extension and retraction of the low-friction cylinder caused by manufacturing errors. A displacement detection unit (4) is provided on one side of the low-friction sliding mechanism (5), and the displacement detection unit (4) provides feedback on the moving distance of the low-friction sliding mechanism (5); Dustproof sealing cloth (12), the dustproof sealing cloth (12) is provided with clamp (13), the dustproof sealing cloth (12) is connected to the shell through clamp (13), and the lower end is connected to the lower telescopic flange (2) through clamp (13). The dustproof sealing cloth (12) isolates the internal components. The low-friction sliding mechanism (5) is a low-friction cylinder. The low-friction cylinder is connected to the pressure regulating valve (3) and the reversing valve (8). Limiting blocks (6) are provided on both sides of the low-friction cylinder. The limiting blocks (6) are connected to the housing. The low-friction cylinder is a bidirectional cylinder. The low-friction cylinder can apply pressure in both directions. The pressure regulating valve (3) regulates the pressure entering the low-friction cylinder and controls the magnitude of the output force. The displacement detection unit (4) is a displacement sensor. The displacement sensor is used to detect the extension length of the low friction cylinder and provide feedback. It is used by the pressure regulating valve (3) to compensate for the output and release of pressure. The displacement sensor monitors the displacement of the low friction cylinder in real time and transmits it back to the host computer through analog signals. It is fed back to the pressure regulating valve (3) to adjust the pressure in real time. The reversing valve (8) is a two-position solenoid valve. It is used for the reversing operation of the low friction cylinder to realize the constant push and pull force of the low friction cylinder. The low-friction sliding mechanism (5) is provided with a tilt angle detection unit (7) on one side. The tilt angle detection unit (7) adopts an angle sensor. The angle sensor calculates the gravitational component applied to the workpiece based on the current angle of the floating grinding mechanism, and compares and calculates it with the set force to achieve a constant force applied to the workpiece in the 360-degree direction.

2. The active floating polishing unit according to claim 1, characterized in that, The low-friction sliding mechanism (5) is equipped with a breathing silencer (11). The breathing silencer (11) is used to compensate for the air pressure changes generated inside and outside the low-friction sliding mechanism (5) during floating and to isolate air impurities.

3. The active floating polishing unit according to claim 1, characterized in that, It also includes a data transmission interface (10), which connects to the pressure regulating valve (3), the reversing valve (8), the displacement detection unit (4), and the tilt detection unit (7); the data transmission interface (10) inputs and outputs displacement, angle, and air pressure data signals to the host computer.

4. A polishing method based on an active floating polishing unit, characterized in that, Using the active floating polishing unit as described in any one of claims 1-3 includes the following steps: S1: Stroke calibration. Start the equipment and slowly reduce the stroke of the floating unit cylinder to the minimum value. Set and record the corresponding analog quantity through the equipment control system. Then, reduce the stroke of the low-friction cylinder to the maximum value and set and record the corresponding analog quantity to complete the stroke calibration. S2: Angle calibration. Place the floating connector horizontally, read the analog value of the angle sensor at this time and record it as AngleMax; then invert the floating connector horizontally, read the analog value of the angle sensor and record it as AngleMin to complete the angle calibration. S3: Weight calibration. Following the weight calibration algorithm steps, the air pressure is gradually adjusted. The budget pressure is recorded each time the low-friction cylinder stroke exceeds a specific length L. The coarse budget air pressure and fine budget air pressure of the load are calculated, and the tool weight G is finally accurately calculated. S4: Constant force output. Before the grinding operation, the constant grinding force F applied to the workpiece is set on the control panel of the host computer according to the material, surface condition and other factors of the workpiece. During the grinding process, the angle θ between the axis of the low friction cylinder and the horizontal plane is read in real time. The real-time output pressure of the cylinder is calculated according to the constant force output algorithm. By controlling the air pressure of the proportional valve, the workpiece is always subjected to a constant grinding force F during the grinding process. S5: End force compensation. During the movement of the low-friction cylinder, the system monitors the changes in cylinder stroke and current status in real time, determines the direction of friction force according to the end force compensation algorithm, and compensates the output force accordingly to ensure that the output force at the end of the floating joint is constant and improves the grinding quality.

5. A polishing method based on an active floating polishing unit according to claim 4, characterized in that, In step S4, the working process of the low-friction cylinder is as follows: a) Gas enters and the gas pressure is controlled by the pressure regulating valve; b) If a downward thrust is required in this state, the solenoid valve does not work, and the gas pressure is introduced into the rodless chamber of the low-friction cylinder to make the cylinder extend downward and provide downward pressure. c. If upward pulling force is required in this state, the solenoid valve reverses its operation, and air pressure is introduced into the rod chamber of the low-friction cylinder to pull the cylinder upward and provide upward pulling force; d. The displacement of the low-friction cylinder is monitored in real time by a displacement sensor, and the analog signal is transmitted back to the host computer to feed back to the pressure regulating valve to adjust the pressure in real time.

6. A polishing method based on an active floating polishing unit according to claim 5, characterized in that, The pressure regulating valve is set with the required force on the host computer control panel. After the required force is set, the system is vented, and the venting is greater than the required force setting. The output pressure of the pressure regulating valve is adjusted by the program in the host computer. The system will automatically eliminate the influence of the grinding tool, friction, and its own weight, so that the force when the grinding tool contacts the workpiece is constant and is the required force.

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