Electric drive intelligent constant force radial compensation system

Abstract

The invention is suitable for the technical field of grinding, and provides an electric drive intelligent constant force radial compensation system which comprises an intelligent electric radial floating grinding device, the intelligent electric radial floating grinding device comprises a dust cover and a linear motor in the dust cover, and the linear motor is composed of a motor stator and a motor rotor. A grinding tool is arranged at the output end of the linear motor, a fixing base is installed on one side of the linear motor, a cone swinging device and an adjusting ring are installed on the fixing base, and the grinding tool and the cone swinging device are sealed in a labyrinth mode and provided with a labyrinth sealing outer ring and a labyrinth sealing inner ring. According to the scheme, the stability of driving force is improved, the mechanism design is optimized, the response speed for responding to external force changes and sealing are achieved, meanwhile, the influence on output torque is reduced to the minimum, the yield of high-precision polishing can be greatly improved, the polishing technological process is simplified, and the polishing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polishing, and particularly relates to an electrically-driven intelligent constant-force radial compensation system. BACKGROUND

[0002] In the polishing industry, with the development of the times and the continuous progress of science and technology, the proportion of customized and high-precision product production continues to increase, and the demand for higher precision polishing is also increasing day by day. Traditional manual polishing not only has low efficiency, but also the quality consistency of products is difficult to guarantee, resulting in high rework rate and thus low production efficiency. Compared with manual polishing, the emergence of pneumatic radial floating polishing tool device has improved the polishing efficiency and precision to a certain extent. There are two common ways of robot automatic polishing on the market at present: trajectory polishing and pneumatic constant-force tool flexible polishing. When the robot polishes according to the trajectory, the removal material thickness is inconsistent due to factors such as workpiece manufacturing, assembly and clamping, and robot precision, and thus the polishing effect is unqualified; the dynamic seat of the pneumatic radial floating polishing tool is combined with an electric spindle, a grinding machine and a reciprocating file, and has a radial 360±5° floating function. It can adapt to the curved surface to realize flexible polishing, which is greatly improved compared with trajectory polishing. However, due to the natural problem of low precision of compressed air, the response speed is often greater than 100 ms, and in addition, when the electric spindle, the grinding machine and other tools deflect in the floating seat according to the adaptive curved surface, the contact points of the internal air cylinder will change, and thus the length of the force arm changes, resulting in changes in the polishing torque from the theoretical design, which makes it difficult to maintain stable quality and high precision requirements in the medium and high precision polishing scene.

[0003] The pneumatic radial floating polishing tool is mainly composed of one or more piston cylinders distributed on the upper part or side of the floating disc, and 0.5-6.0 bar compressed air as driving force. The pressure is stabilized through a pressure reducing valve, and then a relatively stable cylinder thrust is obtained. The cylinder rod acts on the mechanism that can do conical motion, and the polishing tool is passively maintained within 0-5° small amplitude change of polishing force. The pneumatic radial floating polishing tool device fixes the cylindrical polishing tools such as electric spindles, grinding machines and reciprocating files through clamping mechanisms. The polishing tool in the pneumatic radial floating polishing tool device usually swings 360±5°, and the internal components such as air cylinders need a relatively clean environment, and dust covers or dust cloths or rubber sleeves are generally provided.

[0004] 1. The thrust generated by the compressed air-driven cylinder is unstable, with dynamic accuracy typically fluctuating between 1-10N. Pneumatic control generally uses 0.5-6 bar compressed air as the driving force. The volume of this compressed air is prone to change and is also affected by temperature, humidity, and other components in the air, leading to inaccurate output force. This is especially true in scenarios where force control requires frequent adjustments. Unsteady pneumatic cylinders often exhibit even larger deviations, typically reaching 1-10N. Pneumatic floating spindles are usually driven by one or more cylinders. The differences between these cylinders further affect the output magnitude and stability, and the magnitude of the force often directly impacts the grinding effect. Fluctuations within this range often result in substandard grinding results.

[0005] 2. Compressed air has a slow dynamic response, typically within the range of 50-300ms. The speed of compressed air propagation in cylinders and valves generally does not exceed the speed of sound (340m / s). After the control system collects signals, calculates and issues valve control signals, the compressed gas driving the cylinder finally reaches the cylinder through valves, pipelines, and connectors, generating force before stabilizing. During grinding, the changes in grinding force are often on the order of milliseconds, requiring the force control to adjust as quickly and promptly as possible, ideally within 10ms. The 50-300ms response speed of pneumatic force control is insufficient for the precision requirements of medium- to high-precision grinding.

[0006] 3. The radial floating grinding tools in applications 201610842593.5 and 202411152471.4 consist of one or more cylinders acting on a mechanism capable of oscillating 360±5°. The piston rods of the multi-cylinder structure have spherical ends. When the grinding tool oscillates adaptively, the length of the lever arm of the cylinder piston rod changes due to the oscillation. Because the output force of the compressed air-driven cylinders is unstable and the response is slow, it is difficult to adjust the changes in air pressure compensation torque accurately in real time. Changes in grinding torque often cause overcutting and undercutting, resulting in parts that do not achieve the desired machining effect.

[0007] 4. Radial floating grinding tools with application numbers 201610842593.5 and 202411152471.4 are typically used at the end effector of robots. When their posture changes, gravity often significantly impacts the output force. The pistons of cylinders composed of one or more cylinders are usually cylindrical steel bars. Since the effective area of ​​a single cylinder is typically small, in scenarios requiring low grinding force, gravity often accounts for more than 50% of the force generated by the working air pressure. In this case, the effect of gravity becomes significant, leading to large variations in grinding force and consequently, failing to achieve the desired processing effect.

[0008] 5. The radial floating grinding tools with application numbers 201610842593.5 and 202411152471.4 use multiple small cylinders as the driving force, which are evenly distributed above or to the side of the conical oscillating mechanism. Regardless of their density, there will always be gaps between the evenly distributed cylinders. When the grinding tool oscillates, because it can oscillate 360° around the central axis of the grinding tool, the output torque of the floating seat is obtained by integrating the torques of multiple cylinders. When the grinding tool rotates once around the axis of the floating seat at the same oscillation angle, the integral of the torques exerted by the multiple cylinders at different positions is different, resulting in a polygonal variation in the grinding force. This, in turn, leads to unstable quality on the workpiece.

[0009] 6. Poor dust protection or resistance from the dustproof structure affects the accuracy of the grinding force. Since radial floating grinding tools typically contain sliding mechanisms, rotating mechanisms, and cylinders, grinding often takes place in high-dust and high-humidity environments. Poor dust protection directly impacts the output accuracy of the force control. Non-metallic protective covers effectively prevent dust by deforming to meet motion requirements while simultaneously providing a seal. However, the deformation direction of the non-metallic protective cover is often opposite to the output force direction. The deformation output force of moving non-metallic materials is non-linear; as the angular velocity increases, the force required for the same deformation increases accordingly and remains opposite to the output force direction. Therefore, it affects the accuracy of the force control, typically within the range of 0-2N. Due to this non-linear resistance, it is difficult for the force control to balance or compensate for it in the initial stage, affecting the dynamic accuracy of the radial floating grinding tool's output force and leading to poor grinding results.

[0010] In summary, this application proposes an electric drive intelligent constant force radial compensation system. Summary of the Invention

[0011] The purpose of this invention is to provide an electric drive intelligent constant force radial compensation system to solve the problems mentioned in the background art.

[0012] To achieve the above objectives, the present invention provides the following technical solution: an electrically driven intelligent constant force radial compensation system, comprising an intelligent electric radial floating grinding device, the intelligent electric radial floating grinding device comprising a dust cover, an internal linear motor of the dust cover, the linear motor comprising a stator and a mover, a grinding tool at the output end of the linear motor, a fixed base mounted on one side of the linear motor, a conical swing device and an adjusting ring mounted on the fixed base, the grinding tool and the conical swing device employing a labyrinth seal, and having an outer labyrinth seal outer ring and an inner labyrinth seal inner ring, the linear motor electrically connected to an IMU sensor and a displacement sensor, a display screen on the outer wall of the dust cover, the IMU sensor and the displacement sensor both electrically connected to the display screen, the displacement sensor being used to detect the moving distance and speed of the adjusting ring, the IMU sensor being fixed on the adjusting ring, and being used to detect the angle between the intelligent electric radial floating grinding device and gravity and the acceleration of the adjusting ring.

[0013] Preferably, the ball joint device in the conical swing device provides rotational motion in three directions. The conical swing device includes a ball joint inner ring, and steel balls are provided on both sides of the conical swing device and embedded in the ball joint inner ring to limit the rotation of the ball joint inner ring as the grinding tool rotates.

[0014] Preferably, the bottom of the adjusting ring is an annular spherical surface, which contacts the inner ring plane of the ball joint in the cone swing device.

[0015] Preferably, a locking device is provided between the inner ring of the ball joint and the grinding tool, and the two are fixed together by the locking device.

[0016] Preferably, the side wall of the dust cover is provided with a cable quick connector and an air circuit quick connector, and the two sides of the grinding tool are provided with counterweight rings.

[0017] Preferably, a motor connecting plate is connected between the motor actuator and the adjusting ring, and a linear motion device is connected between the adjusting ring and the fixed base.

[0018] Preferably, the ball joint structure in the conical swing device enables a swing of 360±10°. The top and bottom of the inner ring of the ball joint are provided with limiting plates to limit the swing angle to within 0-10°, preventing excessive angles from causing the grinding tool to collide with other components and be damaged.

[0019] Preferably, the top of the inner labyrinth seal ring is provided with a dust-proof groove, and a gap is reserved between the inner labyrinth seal ring and the outer labyrinth seal ring.

[0020] Preferably, the outer wall of the dust cover is provided with a heat dissipation device, which consists of a fan and an air duct, and the linear motor is provided with a temperature sensor.

[0021] Preferably, the dynamic model equations for the grinding tool are as follows:

[0022] ①;

[0023] ②;

[0024] ③;

[0025] ④;

[0026] in: The swing angle of the grinding tool can be obtained through geometric relationship ①;

[0027] The distance from the center of the adjusting ring to the initial plane of the ball joint is obtained by a displacement sensor in the cross-section of the plane between the contact point of the inner ring plane of the ball joint and the adjusting ring and the central axis plane of the grinding tool.

[0028] Design dimensions to adjust the radius of the central circle of the annular sphere at the end of the ring;

[0029] Design dimensions to adjust the radius of the annular sphere at the end of the ring;

[0030] Design the dimension of the distance between the inner ring of the ball joint and the plane symmetrical about the center point of the ball joint, and the parallel distance between the inner ring of the ball joint and the plane in contact with the adjusting ring.

[0031] The perpendicular distance from the line of elastic force at the contact point between the inner ring plane of the ball joint and the adjusting ring to the center of rotation of the ball joint is obtained through geometric relationship ②;

[0032] The thrust output by the linear motor is obtained by fitting the relationship between the current and the output force.

[0033] The elastic force at the contact point between the inner ring plane of the ball joint and the adjusting ring is derived from relation ④ using the theorem of angular momentum.

[0034] The frictional force between the linear guides is determined by both theoretical calculations and actual test data.

[0035] The frictional torque between the ball joints is determined by both theoretical calculations and actual test data.

[0036] The set grinding torque is the initial setting, which is confirmed by the actual grinding process parameters and input into the system.

[0037] The angular inertia of the component rotating about the center of the ball joint is determined by both theoretical calculations and actual test data.

[0038] The angular acceleration of the component rotating around the center of the ball joint is obtained by combining the second derivative of the geometric relationship with the velocity and acceleration from the displacement sensor.

[0039] It is the acceleration due to gravity;

[0040] The angle between the linear motor's direction of motion and the direction of gravity is measured by an IMU sensor.

[0041] This invention has at least the following beneficial effects:

[0042] (1) This solution will greatly improve the yield of medium and high precision grinding, simplify the grinding process and improve grinding efficiency by improving the stability of the driving force, optimizing the mechanism design, responding to changes in external force and sealing, and minimizing the impact on the output torque.

[0043] (2) The high-precision constant torque output of this solution will make the polished surface more consistent, the amount of material removed is uniform and controllable, and thus the finished product yield of the polished product is higher.

[0044] (3) This solution can respond to changes in external force. In the same amount of time, force control can make more adjustments, allowing the process to be polished with faster parameters, such as increasing the grinding feed speed and robot posture change speed, which can effectively shorten the grinding time and improve grinding efficiency.

[0045] (4) For complex curved surfaces, this solution selects appropriate grinding tools and combines them with the high-speed and stable automatic compensation function of electric power control. This can simplify complex contouring trajectories into simple straight lines, arcs, reciprocating swings, spirals, etc., which greatly simplifies the process. Attached Figure Description

[0046] Figure 1 This is a layout diagram of the internal structure of the present invention;

[0047] Figure 2 This is a top view of the layout of the present invention;

[0048] Figure 3 This is a schematic diagram illustrating the appearance layout and movement of the present invention;

[0049] Figure 4 This is a schematic diagram of the labyrinth seal of the present invention;

[0050] Figure 5 This is a schematic diagram of the force analysis of the present invention.

[0051] In the attached diagram, the following are the reference numerals: 1. Grinding tool; 2. Motor connecting plate; 3. Counterweight ring; 4. Quick-connect cable; 5. Dust cover; 6. Fixing base; 7. Linear movement device; 8. Limiting plate; 9. Conical swing device; 10. Inner ring of ball joint; 11. Outer ring of labyrinth seal; 12. Inner ring of labyrinth seal; 13. Gap; 14. Quick-connect air passage; 15. Motor stator; 16. Motor mover; 17. Adjusting ring; 18. Locking device; 19. Heat dissipation device; 20. IMU sensor; 21. Displacement sensor; 22. Display screen; 23. Dust shielding groove. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] The grinding tool of this invention employs a linear motor with high dynamic response characteristics. Through a low-friction conical oscillation mechanism, and utilizing sensors such as force sensors, displacement sensors, and IMU sensors, it achieves precise closed-loop control via a microcomputer or PLC through dynamic modeling. This results in a 360±10° oscillation and a constant grinding torque output of 0-100 N·m, with an accuracy of 0.03-0.5%FS. The moving parts utilize a labyrinth seal.

[0054] Based on the above technical solutions, the following embodiments are provided in this regard:

[0055] Example

[0056] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5This invention provides a technical solution: an electrically driven intelligent constant force radial compensation system, including an intelligent electric radial floating grinding device. The intelligent electric radial floating grinding device includes a dust cover 5, an internal linear motor of the dust cover 5, the linear motor consisting of a motor stator 15 and a motor mover 16, and a grinding tool 1 at the output end of the linear motor. Specifically, the grinding tool 1 is an electric spindle, a reciprocating file, a grinding machine, etc. A fixed base 6 is installed on one side of the linear motor, and a conical swing device 9 and an adjusting ring 17 are installed on the fixed base 6. The grinding tool 1 and the conical swing device 9 adopt a labyrinth seal, and are provided with a labyrinth seal outer ring 11 and a labyrinth seal inner ring 12. The linear motor is electrically connected to an IMU sensor 20 and a displacement sensor 21. A display screen 22 is provided on the outer wall of the dust cover 5, and both the IMU sensor 20 and the displacement sensor 21 are electrically connected to the display screen 22.

[0057] This electrically driven intelligent constant force radial compensation system consists of a grinding tool such as an electric spindle / reciprocating file / grinding machine 1, a linear motor mover 16 and a motor stator 15, a counterweight ring 3, an adjusting ring 17 and an adjusting ring seat, a locking mechanism 18, a linear movement device 7, a displacement sensor 21, an IMU sensor 20, a heat dissipation device 19, a display screen 22, a cable quick connector 4, an air circuit quick connector 14, and a dust cover 5. Figure 1 , Figure 2 and Figure 3 As shown. The fixed base 6 is used to fix the linear motor and linear movement device 7, the conical swing device 9 and the adjusting ring 17, etc. The dust cover 5 serves to prevent dust and protect the internal parts. The conical swing motion between the grinding tool 1 and the body adopts a labyrinth seal.

[0058] The linear motor consists of a motor mover 16 and a motor stator 15, controlled by a dedicated driver, serving as the power source for electrodynamic control. Parameters output from IMU sensor 20 and displacement sensor 21 directly influence the position, force, and speed control of the linear motor. Displacement sensor 21 detects the moving distance and speed of the adjustment ring 17. IMU sensor 20, fixed to the adjustment ring 17, detects the angle between the intelligent electric radial floating grinding device and gravity, as well as the acceleration of the adjustment ring 17, under different postures at the robot's end effector. Heat dissipation device 19 is used for cooling the motor and the entire radial floating grinding device. The motor mover 16 and adjustment ring 17 of the linear motor are connected via motor connecting plate 2 to transmit power.

[0059] The ball joint mechanism in the cone-shaped swing provides rotational motion in three directions. Steel balls on both sides are embedded in the inner ring 10 of the ball joint to limit the rotation of the inner ring 10 as the grinding tool 1 rotates. The expansion ring in the locking device 18 fixes the grinding tool 1 to the inner ring 10 of the ball joint.

[0060] The motor mover 16 and adjusting ring 17 of the linear motor are connected by the motor connecting plate 2, and the adjusting ring 17 and the fixed base 6 are connected by the linear moving device 7. The bottom of the adjusting ring 17 is an annular spherical surface, which contacts the plane of the inner ring 10 of the conical swing device 9. The inner ring 10 of the ball joint and the grinding tool 1 are fixed together by the locking device 18. The motor mover 16 and the adjusting ring 17 of the linear motor share a set of moving devices. The electromagnetic force generated by the linear motor is transmitted to the inner ring 10 of the conical swing through the contact force of the annular spherical surface at the end of the adjusting ring 17. The grinding tool 1 is fixed to the inner ring 10 of the ball joint. When the grinding tool 1 is subjected to grinding force, the inner ring 10 of the ball joint will deflect. The force is transmitted to the linear motor through the contact point between the annular spherical surface at the end of the inner ring 10 and the plane of the inner ring 10 of the ball joint. The linear motor adjusts the output force of the motor in real time according to the set grinding torque to ensure the constant torque under various swing angles. The ball joint structure in the conical swing device 9 enables a swing of 360±10°. Limiting plates 8 are provided at the top and bottom of the inner ring 10 of the ball joint, thus limiting the swing angle to within 0-10° and preventing damage caused by excessive angles leading to collisions between the grinding tool 1 and other components. Since the grinding tool 1 is cylindrical, its center of gravity is generally on the central axis. The grinding tool 1 is mounted on the inner ring 10 of the ball joint, and its center of gravity must coincide with the center of the ball joint. The counterweight ring 2 effectively solves the problem of the tool's position not coinciding with its center of gravity. When the grinding tool 1 and the center of the ball joint coincide, the lever arm affecting the grinding torque is 0. Therefore, under different postures, the gravity of the grinding tool 1 will no longer affect the grinding torque; only the effect of its rotational inertia needs to be considered.

[0061] When the grinding tool 1 is not under force, the electromagnetic force between the motor mover 16 and the motor stator 15 of the linear motor will press the adjusting ring 17 onto the plane of the inner ring 10 of the ball joint. At this time, the adjusting ring 17 and the inner ring 10 of the ball joint are in line contact, and the swing angle of the grinding tool 1 is 0. When the end of the grinding tool 1 is under force, the inner ring 10 of the ball joint will deflect under the action of torque. At this time, the adjusting ring 17 and the inner ring 10 of the ball joint will change from line contact to point contact. Moreover, no matter which direction the swing occurs within 360°, it will still be point contact. As long as the swing angle is the same, the distance between the contact point and the center of the ball joint will not change, thus ensuring the accurate theoretical design basis. The annular spherical structure at the end of the adjusting ring 17 can be considered as being formed by countless balls rotating in a circle. When the swing angle of the inner ring 10 of the ball joint changes, the contact point will change, which will affect the length of the force arm. At this time, the change of the force arm is calculated according to the geometric relationship. According to the torque balance principle, the linear motor can complete the adjustment of the motor output force at the millimeter level, thus ensuring the constant grinding torque. The gravity of the motor mover 16, motor connecting plate 2, adjusting ring 17 and linear motion device 7 will affect the magnitude of the actual output force. The IMU sensor 20 can measure the angle between the linear motor's motion direction and gravity in real time. By adjusting the output force of the linear motor, the influence of gravity can be compensated.

[0062] The heat dissipation device 19 typically consists of a fan and air ducts. The system uses a temperature sensor inside the linear motor to adjust the airflow for heat dissipation, ensuring continuous motor operation. The grinding tool 1 performs a conical oscillation; to ensure smooth movement and minimize resistance from the seal, a labyrinth seal is used. Figure 1 As shown. The labyrinth seal outer ring 11 is a frustum thin-walled structure, fixed to a stationary conical oscillating mechanism, and the labyrinth seal inner ring 12 is a spherical thin-walled structure, fixed to the grinding tool 1. When the grinding tool 1 oscillates within the range of 0-10°, the sealing gap 13 does not change significantly; when the labyrinth seal outer ring 11 opens downwards, the positive pressure formed by compressed air inside the electrically driven intelligent constant force radial compensation system makes it difficult for dust and water to enter the device through the gap; when the labyrinth seal outer ring 11 opens upwards, even if a small amount of dust or water enters the device through the gap 13, it will be blocked by the annular retaining ring at the end of the labyrinth seal inner ring 12; when the labyrinth seal outer ring 11 opens downwards again, the dust and water will be expelled from the device under the action of airflow and gravity, such as Figure 4 .

[0063] Typically, there is a stable linear relationship between the output force and the current of a linear motor. By controlling the current through the linear motor driver, the output force of the motor can be precisely controlled. Its coefficients can be obtained by fitting the measured motor current and output force data. The displacement sensor 21 can measure the displacement of the linear motor. ,speed and acceleration The IMU sensor 20 can measure the angle between the direction of linear motor motion and gravity. This allows us to calculate the gravitational component in the direction of linear motor motion. To obtain a constant output torque for the grinding tool 1, it is necessary to control the output force of the motor to balance the changing forces in the system. These changing forces mainly include the gravitational component along the direction of motion, the inertial force of the linear motor, and the elastic force at the contact point between the adjusting ring 17 and the inner ring 10 of the ball joint. And the sliding friction of the linear motion device Frictional torque of ball joint rotation Equal resistance, such as Figure 5 Based on the geometric dimensional relationships, the equations for equilibrium of concurrent forces, the theorem of angular momentum, and the equations for dynamic equilibrium, the dynamic model equations for grinding tool 1 are constructed as follows:

[0064] ①;

[0065] ②;

[0066] ③;

[0067] ④;

[0068] in: The swing angle of the grinding tool 1 can be obtained through geometric relationship ①;

[0069] The distance from the center of the adjustment ring 17 to the initial plane of the ball joint in the cross section of the plane between the contact point of the inner ring 10 of the ball joint and the adjustment ring 17 and the central axis plane of the grinding tool 1 is obtained by displacement sensor 21.

[0070] Design dimensions to adjust the radius of the central circle of the annular spherical surface at the end of ring 17;

[0071] To adjust the radius of the annular spherical sphere at the end of ring 17, design the dimensions;

[0072] Design dimension for the distance between the inner ring 10 of the ball joint and the plane of the ball joint inner ring 10 that is symmetrical about the center point of the ball joint and the plane of the ball joint inner ring 10 that contacts the adjusting ring 17;

[0073] The perpendicular distance from the line of elastic force at the contact point between the inner ring 10 plane of the ball joint and the adjusting ring 17 to the center of rotation of the ball joint is obtained through geometric relationship ②.

[0074] The thrust output by the linear motor is obtained by fitting the relationship between the current and the output force.

[0075] The elastic force at the contact point between the inner ring 10 plane of the ball joint and the adjusting ring 17 is derived from relation ④ using the theorem of angular momentum.

[0076] The frictional force between the linear guides is determined by both theoretical calculations and actual test data.

[0077] The frictional torque between the ball joints is determined by both theoretical calculations and actual test data.

[0078] The set grinding torque is the initial setting, which is confirmed by the actual grinding process parameters and input into the system.

[0079] The angular inertia of the component rotating about the center of the ball joint is determined by both theoretical calculations and actual test data.

[0080] The angular acceleration of the component rotating around the center of the ball joint is obtained by combining the second derivative of the geometric relationship with the velocity and acceleration of the displacement sensor 21.

[0081] It is the acceleration due to gravity;

[0082] The angle between the linear motor's direction of motion and the direction of gravity is measured by IMU sensor 20.

[0083] Based on the above data and relationships, the current required by the linear motor is calculated in real time using a microcomputer and PLC computing unit, and the linear motor driver maintains a constant output grinding torque. Because uncertain deviations may occur in the system, it is also necessary to compare the torque calculated from multiple sensor parameters with the set force, and perform negative feedback adjustment based on the deviation.

[0084] The response speed of linear motors is often in the microsecond range. Since electricity travels at the speed of light, the current loop of a linear motor can often complete the response in just 100-1000 ns. This response speed is more than a thousand times that of the pneumatic circuit. Therefore, electrodynamic control can complete the control in the millisecond range, which plays a decisive role in the dynamic accuracy of the output constant force.

[0085] Compared with common pneumatic radial floating grinding devices, the intelligent electric radial floating grinding device has higher static and dynamic accuracy, smoother operation, faster response speed, and less impact of sealing on output torque. The specific key points of this invention are as follows:

[0086] ① Replace one or more cylinder power systems with one or more linear motor power systems. Linear motors include, but are not limited to, coreless linear motors, cored linear motors, and magnetic shaft motors. The highly linear relationship between the current and output force of linear motors solves the problem of unstable linear relationship between cylinder output force and air pressure. The advantages of intelligent electric radial floating grinding devices are particularly evident in dynamic adjustment processes. Typically, the dynamic accuracy of pneumatic radial floating grinding tools is affected by temperature, resistance, etc., with output force fluctuations ranging from 1-5 N·m (based on data from tests and evaluations of multiple brands and models on the market). Linear motors, with their high response frequency, high stability, and theoretically precise design, allow output torque fluctuations ranging from 0-0.5 N·m (theoretical calculations and prototype evaluations). In grinding applications, intelligent electric radial floating grinding devices can output more stable grinding torque, resulting in better, more stable, and controllable surface quality after grinding.

[0087] ② The intelligent electric radial floating grinding device can achieve a millisecond-level response, which is thousands of times faster than the response speed of pneumatic control. The speed of compressed air in the cylinder and valve is no higher than the speed of sound (340m / s), while the current in the linear motor propagates at the speed of light (3.0x10⁻¹⁰). 5 (m / s). High response speed not only improves dynamic accuracy but also shortens process time, increasing grinding efficiency by 1-10 times. Because the response of electrodynamic control is in the millisecond range, compared to the tens or even hundreds of milliseconds of pneumatic control, the grinding process can improve efficiency through faster feed and quicker robot posture switching.

[0088] ③ The intelligent electric radial floating grinding device can achieve precise torque control in real time. Utilizing the high stability and response speed of linear motors, the device can adjust the output force of the linear motor within milliseconds when torque changes. Since millisecond-level changes in mechanical position are typically greater than but less than micrometers, the output torque can maintain high precision. In contrast, pneumatic control offers a response time of hundreds of milliseconds. By the time the adjusted air pressure stabilizes, the lever arm may have already changed by millimeters. Furthermore, compressed air is affected by many factors, limiting the effectiveness of real-time adjustment for pneumatic radial floating grinding tools.

[0089] ④ The intelligent electric radial floating grinding device can compensate for the influence of gravity in real time. Equipped with an IMU sensor, the electric radial floating device can monitor the tool's posture at the robot's end effector in real time, obtaining the angle between the linear motor's direction of motion and gravity. Based on the weight of the moving part and the cosine of the angle, the component of gravity can be obtained. Then, through linear motor compensation, the influence of gravity on the device can be effectively avoided. In contrast, the weight of the cylinder piston in a pneumatic radial floating grinding tool device is usually negligible, which results in significant fluctuations when outputting small grinding torques (0.1-0.5 Nm), rendering it unusable.

[0090] ⑤ The intelligent electric radial floating grinding device outputs a stable and consistent torque during its 360° conical motion around the center of the ball joint. The intelligent electric radial floating grinding device uses a ring-shaped spherical structure to transmit torque through point contact with the ball joint plane. Regardless of the direction, the force state within the plane passing through the contact point and the outer ring axis of the ball joint is consistent. In contrast, pneumatic control systems, due to their multiple cylinder distribution, exhibit a significant polygonal effect.

[0091] ⑥ Labyrinth sealing method for moving parts. External gases, dust, or droplets must pass through narrow, elongated gaps to enter the interior, resulting in significant resistance and making entry difficult. Furthermore, positive airflow through the labyrinth channels further increases resistance to dust or gas entry, ensuring a tight seal. Because there is no contact, the impact on torque is minimized. Grinding environments are often characterized by high dust, high humidity, and high debris levels. Sealing components rely on the deformation of non-metallic materials, providing good sealing, but the friction between the seal and the sealing surface affects the constant torque output. Dust covers rely on their own deformation for sealing, offering good sealing, but the resistance to deformation is often influenced by various factors, directly affecting the constant force output.

[0092] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all changes falling within the meaning and scope of the equivalents of the claims be included within the present invention, and no reference numerals in the claims should be regarded as limiting the scope of the claims.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electrically driven smart constant force radial compensation system, characterized in that, The application relates to an intelligent electric radial floating polishing device, which comprises a dustproof cover (5), an internal linear motor of the dustproof cover (5), wherein the linear motor is composed of a motor stator (15) and a motor rotor (16), the output end of the linear motor is provided with a polishing tool (1), one side of the linear motor is provided with a fixing base (6), the fixing base (6) is provided with a conical body oscillating device (9) and an adjusting ring (17), the polishing tool (1) and the conical body oscillating device (9) adopt labyrinth sealing and are provided with a labyrinth sealing outer ring (11) and a labyrinth sealing inner ring (12), the linear motor is electrically connected with an IMU sensor (20) and a displacement sensor (21), the outer wall of the dustproof cover (5) is provided with a display screen (22), the IMU sensor (20) and the displacement sensor (21) are electrically connected with the display screen (22), the displacement sensor (21) is used for detecting the moving distance and speed of the adjusting ring (17), the IMU sensor (20) is fixed on the adjusting ring (17) and is used for detecting the included angle between the intelligent electric radial floating polishing device and gravity and the acceleration of the adjusting ring (17).

2. The electrically driven smart constant force radial compensation system of claim 1, wherein: The ball hinge device in the conical body oscillating device (9) provides three-direction rotating movement, the conical body oscillating device (9) is provided with steel balls on two sides and is embedded into the ball hinge inner ring (10) and is used for limiting the rotation of the ball hinge inner ring (10) with the polishing tool (1).

3. The electrically driven smart constant force radial compensation system of claim 2, wherein: The bottom of the adjusting ring (17) is an annular spherical surface which is in plane contact with the ball hinge inner ring (10) in the conical body oscillating device (9).

4. The electrically driven smart constant force radial compensation system of claim 1, wherein: The ball hinge inner ring (10) and the polishing tool (1) are provided with a locking device (18) and are fixed together through the locking device (18).

5. The electrically driven smart constant force radial compensation system of claim 1, wherein: The side wall of the dustproof cover (5) is provided with a cable quick plug (4) and an air path quick plug (14), and the two sides of the polishing tool (1) are provided with counterweight rings (3).

6. The electrically driven smart constant force radial compensation system of claim 1, wherein: The motor rotor (16) and the adjusting ring (17) are connected with a motor connecting plate (2), and the adjusting ring (17) and the fixing base (6) are connected with a linear moving device (7).

7. The electrically driven smart constant force radial compensation system of claim 1, wherein: The ball hinge structure in the conical body oscillating device (9) realizes 360+-10 DEG oscillation, the top and bottom of the ball hinge inner ring (10) are provided with limiting plates (8), so that the oscillation angle is limited within 0-10 DEG, and damage of the polishing tool (1) and other components caused by collision is prevented.

8. The electrically driven smart constant force radial compensation system of claim 1, wherein: The top of the labyrinth sealing inner ring (12) is provided with a dustproof groove (23), and a gap (13) is reserved between the labyrinth sealing inner ring (12) and the labyrinth sealing outer ring (11).

9. The electrically driven smart constant force radial compensation system of claim 1, wherein: The outer wall of the dustproof cover (5) is provided with a heat dissipation device (19), the heat dissipation device (19) is composed of a fan and an air path, and the linear motor is internally provided with a temperature sensor.

10. The electrically driven smart constant force radial compensation system of claim 1, wherein: The kinetic model equation of the polishing tool (1) is as follows: ①； ②； ③； ④； in: The swing angle of the grinding tool (1) can be obtained through geometric relationship ①; The distance from the center of the adjustment ring (17) to the initial plane of the spherical hinge, in the cross section of the plane of contact of the inner ring (10) of the spherical hinge with the adjustment ring (17) and the central axis of the polishing tool (1), is obtained by means of the displacement sensor (21); To adjust the radius of the spherical center circle of the annular spherical surface at the end of the ring (17), design the size; To adjust the radius of the annular spherical ball at the end of ring (17), design the dimensions; Design the dimension for the parallel distance between the distance from the spherical hinge inner ring (10) to the center point symmetry plane of the spherical hinge and the plane of the spherical hinge inner ring (10) in contact with the adjusting ring (17). The vertical distance of the elastic straight line from the contact point of the plane of the inner ring (10) of the spherical hinge to the center of rotation of the spherical hinge is obtained by geometric relationship ②. The thrust force output by the linear motor is obtained by fitting the relationship between the current and the output force. The relationship ④ is derived from the momentum theorem, which is the elastic force of the contact point between the inner ring (10) of the spherical hinge and the adjusting ring (17). The friction force between the linear guide rails is confirmed by theoretical calculation and actual test data. The friction torque between the spherical hinges is obtained by theoretical calculation and actual test data. For the set polishing torque, the initial set amount is confirmed by the actual polishing process parameters and input into the system; The angular moment of inertia of the component rotating around the center of the spherical hinge is obtained from the theoretical calculation and the actual test data. For the angular acceleration of the part rotating with the center of the spherical hinge, the second derivative of the geometric relationship is combined with the speed and acceleration of the displacement sensor (21) and the like to obtain; g is the gravitational acceleration; is the angle between the direction of motion of the linear motor and the direction of gravity, measured by the IMU sensor (20).

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