Force-controlled universal floating polishing device for robot and control method of force-controlled universal floating polishing device

Abstract

The invention relates to a force-controlled universal floating polishing device for a robot and a control method of the force-controlled universal floating polishing device, and belongs to the technical field of force-controlled polishing devices and robot intelligent control. A sleeve and a polishing motor of the polishing device are connected with a shell, a protecting cover, an adjusting wheel and a supporting wheel which are installed together through rubber springs, and six degrees of freedom of a datum point of a polishing head are limited through the rubber springs. The multi-dimensional movement of the polishing head is regulated and controlled by adjusting the rotating angle of the control motor, and force-controlled universal floating polishing is achieved. According to the control method, an operation model is established, a rubber spring is preferably selected through a machining experiment, the rotating angles of a control motor when a datum point of a grinding head reaches different positions are optimized, the control precision is improved, the grinding effect is enhanced, the machining efficiency is improved, the control method adapts to workpiece blanks of different models, and the grinding effect of different structural features is met. During polishing, the stored rotation angle of the control motor is called only according to the position of the polishing head, and combination of active force control and passive force control can be achieved.

Description

Technical Field

[0001] The present invention relates to a robotic force-controlled grinding device and its control method, belonging to the technical fields of force-controlled grinding devices and robotic intelligent control. Background Technique

[0002] The tolerances of workpiece blanks are relatively large, generally between 0.1 mm and 2 mm, and they also have gates, flash, burrs, parting lines, etc., which need to be ground. The grinding of workpiece blanks generates noise and dust, causing serious environmental pollution. With the rapid development of industrial robots and artificial intelligence technologies, the wave of "replacing humans with robots" has swept through the manufacturing industry. Currently, robots are generally used to replace humans for the grinding operation of workpiece blanks.

[0003] Due to the relatively large tolerances of workpiece blanks, in order to ensure sufficient contact between the grinding head and the workpiece and obtain the required grinding effect, existing grinding robots require force control. The invention patent with the application number 202211626145.3 discloses a three-dimensional force-controlled floating grinding device, including a first frame, a Z-axis component, a Y-axis component, and an X-axis component; the Z-axis component is driven by a first motor and is connected with a first tension-compression sensor, the Y-axis component includes a second frame, a second tension-compression sensor, and a Y-axis hydraulic cylinder, and the X-axis component includes a third frame, a third tension-compression sensor, and an X-axis hydraulic cylinder; it can achieve multi-dimensional constant force grinding and improve the grinding quality. The invention patent with the application number 202310653228.X discloses an electromagnetic direct-drive robotic radial floating grinding end effector, including a stator, a rotor, and a connecting mechanism; it uses the principle of Ampere force to generate a driving torque to drive the rotor to rotate, realizing the radial floating of the end effector along the surface of the workpiece to be processed, improving the force control accuracy and response speed. Applied to grinding robots, it can perform two-degree-of-freedom high-precision grinding on workpieces with different surface shapes, improving the polishing quality, precision, and efficiency. The invention patent with the application number 201710811731.8 discloses a radial constant force floating device, including a cylinder barrel and a piston. The cylinder barrel is sleeved outside the piston and forms an air chamber with the piston. An air inlet is provided on the cylinder barrel, and the air inlet is connected to the air chamber; it makes the grinding pressure constant and can absorb the curve deviation between the processing path and the workpiece blank to be processed. It can be seen that existing workpiece blank grinding robots generally install force control devices and use hydraulic, electromagnetic, and pneumatic principles for force control.

[0004] In order to achieve multi-dimensional force control, research has been carried out, and various technical solutions have been proposed at present. The invention patent with the application number 201610963759.9 discloses a flexible grinding device, which includes a power source unit, an output execution unit and a flexible shaft, and also includes an axial floating unit and / or a radial floating unit to achieve axial floating and / or radial floating; the axial floating unit and / or the radial floating unit are used to absorb the curve deviation between the processing path and the material to be processed; since the flexible shaft can transmit greater power, it can grind flash, gates and welds, increasing the processing range. The invention patent with the application number 202310622022.0 discloses an XYZ three-axis floating force control device, which includes an outer housing, and an inner body is fixedly installed inside the outer housing; a plurality of induction processing components are annularly arranged on the outer surface of the inner body to improve the precise control effect of the contact force between the grinding tool and the casting, and ensure the control of the grinding cutting force. At present, there are also various floating grinding technologies. For example, the utility model patent with the application number 202223140280.5 discloses a floating grinding head for an industrial robot, which includes a tool holder, a fixed holder is arranged below the tool holder, and a hundred-leaf wheel chuck is arranged at the lower end of the fixed holder; a floating guide rod is arranged between the fixed holder and the hundred-leaf wheel chuck; the spring provides floating power, and the elastic force is strong and stable; it reduces the workload of robot automatic grinding teaching and effectively reduces the teaching difficulty; the floating distance is adjustable, which can increase the service life of the hundred-leaf blades (grinding consumables) and reduce the grinding cost; the structure is simple and the consumables are convenient to replace. The invention patent with the application number 202110921558.3 discloses a floating tool holder, which includes a tool holder, a fixed housing and a floating tool rod; it changes with the change of the position of the part blank, automatically avoids, and is used to remove burrs or process chamfers, with a simple structure and good use effect.

[0005] It can be seen that the multi-dimensional force control of existing grinding robots is active, with a complex structure, a wide application range, high control accuracy, and high costs; the existing floating grinding technologies generally use floating tool holders, which are passive, with a relatively simple structure, low control accuracy, and low costs; there is an obvious technical contradiction of "active force control is complex, with high precision and high costs; passive force control is simple, with low precision and low costs". With the rapid development and application of new generation information technologies such as artificial intelligence, the Internet of Things, and cloud computing, the intelligent level of grinding robots is constantly improving; in addition, the workpiece blanks of specific manufacturing enterprises are of a single type, and the grinding robots used are generally targeted at specific scenarios. Therefore, it is necessary to further research and improve the force control floating grinding device of the robot and its control method. Summary of the Invention

[0006] The purpose of the present invention is to provide a force-controlled universal floating grinding device for robots and a control method thereof, which uses a rubber spring to improve the structure of the grinding device to achieve force-controlled universal floating grinding; uses a motor to achieve intelligent control, improves the adjustment ability and control accuracy, enhances the grinding effect, and improves the processing efficiency; combines active force control with passive force control to solve the technical contradiction of "active force control is complex, with high accuracy and cost; passive force control is simple, with low accuracy and cost". The specific technical solutions of the present invention are as follows.

[0007] A force-controlled universal floating grinding device for a robot comprises a grinding head, a housing, a rubber spring, a sleeve, a grinding motor, a control motor, an end cover, a bushing and a sleeve. The housing is installed on the robot's manipulator, the grinding head is installed through the bushing, and universal floating force control is performed through the rubber spring and the control motor to achieve force-controlled universal floating grinding of a workpiece blank. The housing comprises a cylindrical shell and a mounting tube that are perpendicular to each other, and the housing is installed on the robot's manipulator through the mounting tube. The housing has an adjusting wheel and a supporting wheel installed on the housing, the upper end of the rubber spring is pressed by the adjusting wheel, and the supporting wheel is meshed with the adjusting wheel to support the adjusting wheel and adjust its rotation angle, so as to adjust and limit the lateral position of the upper end of the rubber spring and the upper part of the sleeve.

[0008] The adjusting wheel includes a circular eccentric through hole, and the sleeve passes through the eccentric through hole at the upper part. The adjusting wheel can rotate relative to the sleeve, so that the adjusting wheel can adjust and limit the lateral position of the upper part of the sleeve. The shell is an upright cylindrical structure, and a closing is formed at the lower end; so that the rubber spring passes through the closing, and the rubber spring can freely expand and contract. The closing is a longitudinal non-circular through hole, which cooperates with the lower part of the outer surface of the rubber spring to limit the lateral position of the rubber spring and the sleeve at the lower part, and prevent the rubber spring from rotating relative to the shell. The rubber spring is a longitudinal straight cylindrical structure, including an inner hole, and the sleeve is passed through the inner hole; the rubber spring abuts against the adjusting wheel at the upper end and the end cover at the lower end, and is subjected to compression. The sleeve is a longitudinal cylindrical structure, including an inner hole, and the shaft sleeve is passed through the inner hole.

[0009] The grinding motor is mounted on the upper end of the sleeve. The grinding motor includes a main shaft, which is fastened to the sleeve through the main shaft to drive the grinding head to perform force-controlled universal floating grinding. The control motor is mounted on the housing; the control motor is connected to the support wheel, drives the support wheel, and drives and adjusts the rotation angle of the adjustment wheel. The end cover is an upward circular cover-shaped structure, which includes a through hole in the center, and is mounted on the lower end of the sleeve using the through hole to prevent the end cover from rotating relative to the sleeve.

[0010] The grinding head includes a head and a shank. The head includes hard abrasives or cutter teeth on its surface. The shank is a straight rod structure for clamping and is also called a tool shank. When the grinding head includes cutter teeth on its head, it is also called a file head. The housing accommodates a rubber spring and a sleeve through the shell. The housing installs a protective cover, an adjusting wheel, and a supporting wheel on the shell. The upper end of the rubber spring is pressed by the adjusting wheel, and its upper horizontal position is adjusted. The supporting wheel meshes with the adjusting wheel to support the adjusting wheel and adjust its rotation angle, so as to adjust and define the horizontal positions of the upper end of the rubber spring and the upper part of the sleeve relative to the housing.

[0011] The shell is a vertical cylindrical structure, inwardly converging at the lower part and including a surrounding groove on the lower part of its outer surface. The sheath is fixedly installed through the groove. The shell forms a constricted opening at the lower end, so that the rubber spring passes through the constricted opening and can freely expand and contract. The shell protrudes outward at the upper end to form a horizontally placed flange. The flange includes a longitudinal shaft hole and fastening holes. The supporting wheel is installed using the shaft hole, and fasteners pass through the fastening holes to achieve the firm installation of the protective cover on the shell.

[0012] The protective cover is an oblong cover, with its outer edge bent downward to form a lower edge, presenting a cover-like structure. The protective cover is firmly installed on the shell by abutting the upper surface of the outer edge of the shell flange through the lower edge. At the horizontal position corresponding to the fastening holes of the shell, the protective cover includes through holes. Fasteners pass through the through holes and the fastening holes of the shell together to achieve the firm installation of the protective cover on the shell. The protective cover includes a longitudinally penetrating middle hole in the middle. The sleeve passes through the middle hole, so that the shell can accommodate the sleeve to avoid interference. The middle hole of the protective cover is circular, coaxial and parallel to the adjusting wheel. The protective cover includes an annular groove on the lower surface of the edge of its middle hole to achieve dynamic sealing relative to the adjusting wheel. Further, at the horizontal position corresponding to the shaft hole of the shell, the protective cover includes a shaft hole, and the supporting wheel is installed using the shaft hole, so that the supporting wheel is supported and can rotate relatively.

[0013] The adjusting wheel is a disc-shaped gear, which includes teeth on its outer circumferential surface and meshes with the supporting wheel through the teeth. An annular sealing ring is fixedly installed outside the upper surface. The sealing ring is an annular structure, coaxial with the adjusting wheel, elastic, and is snapped into the annular groove of the protective cover, so that the adjusting wheel abuts against the protective cover through the sealing ring to achieve dynamic sealing and prevent chips and dust from invading. The adjusting wheel includes a circular eccentric through hole, so that the sleeve passes through the eccentric through hole at the upper part and has a clearance fit with it, and can rotate relatively, so that the adjusting wheel can adjust and limit the lateral position of the upper part of the sleeve by rotating. The lower end of the eccentric through hole of the adjusting wheel preferably has an enlarged diameter to form a flared opening, which cooperates with the upper end of the rubber spring to ensure a clearance fit between the sleeve and the eccentric through hole of the adjusting wheel and a uniform clearance, so that the sleeve is connected to the adjusting wheel through the rubber spring at the upper part to avoid vibration and noise.

[0014] The supporting wheel is a disc-shaped gear, which includes a longitudinal axle in the center and teeth on its outer circumferential surface, and meshes with the teeth of the adjusting wheel through the teeth to support and limit the lateral position of the adjusting wheel, so that the adjusting wheel can adjust and limit the lateral position of the upper part of the sleeve. The axle of the supporting wheel is installed in the axle hole of the protective cover and the axle hole of the housing, so that the supporting wheel is supported and can rotate relatively. Further, there are at least three supporting wheels to limit the lateral position of the adjusting wheel, one of which is used as the driving wheel and the rest are used as driven wheels; the adjusting wheel is driven to rotate by the supporting wheel used as the driving wheel to adjust the lateral position of the upper part of the sleeve. The axle of the supporting wheel used as the driving wheel is connected to the control motor to obtain a driving torque, drive and adjust the rotation angle of the adjusting wheel to adjust and limit the lateral position of the upper part of the sleeve. The groove surrounds the lower part of the outer surface of the housing, is annular and recessed inward to facilitate the fixed installation of the sheath through the groove to prevent the sheath from loosening or falling off.

[0015] The axle hole of the housing is a longitudinal round hole, located on the upper surface of the flange of the housing, and cooperates with the axle of the supporting wheel, so that the supporting wheel is supported. The axle hole for installing the supporting wheel used as the driven wheel is a blind hole. The axle hole for installing the supporting wheel used as the driving wheel is a through hole, which penetrates the flange of the housing up and down, so that the axle of the supporting wheel used as the driving wheel can be connected to the control motor.

[0016] The necking is a longitudinal non-circular through hole, located at the lower end of the housing, passes through the lower part of the rubber spring, and cooperates with the lower part of the outer surface of the rubber spring, so that the rubber spring can pass through the necking, and the rubber spring can freely expand and contract to limit the lateral position of the rubber spring and the sleeve at the lower part and prevent the rubber spring from rotating relative to the housing.

[0017] The fastening hole of the housing vertically penetrates the flange of the housing so as to pass the fastener through to realize the fastening installation of the cover on the housing. When the fastener is a bolt and a nut, the fastening hole is a plain hole; when the fastener is a screw, the fastening hole is a screw hole; the screw hole includes an internal thread, and the internal thread cooperates with the screw to realize fastening.

[0018] The mounting cylinder is a horizontal cylinder, which is fastened to the outer side of the housing at the right end to form an integral body, and includes a flange at the left end, and is fastened to the robot's manipulator through the flange, so that the grinding device is installed on the robot's manipulator. The mounting cylinder includes a through hole on its flange, and a fastener is passed through the through hole to achieve a fastening connection with the robot's manipulator.

[0019] The rubber spring is a longitudinal straight cylindrical structure, including a circular inner hole, through which the sleeve is passed; the rubber spring abuts against the lower surface of the adjusting wheel at the upper end, and abuts against the upper surface of the end cover at the lower end, and is subjected to compression. The rubber spring preferably protrudes upward at the upper end of the inner hole to form a lip, and is inserted into the gap between the sleeve and the flared lower end of the eccentric through hole of the adjusting wheel through the lip, ensuring that the gap is matched and the gap is uniform to avoid vibration and noise.

[0020] The rubber spring contains a cylindrical spiral steel wire inside, and rubber is wrapped around the steel wire to enhance stability and load-bearing capacity, so it is also called a composite spring. The rubber spring contains cut planes evenly distributed along the circumference on the outer surface, so that the rubber spring presents a non-circular cross-section. The lower part of the outer surface of the rubber spring cooperates with the closing of the lower end of the shell, so that the rubber spring can pass through the closing, and the rubber spring can freely expand and contract to limit the lateral position of the rubber spring and the sleeve at the bottom, and prevent the rubber spring from rotating relative to the shell. The rubber spring contains an axial groove on the lower end surface, and the axial groove is used to cooperate with the end cover to prevent the rubber spring from rotating relative to the end cover.

[0021] The sleeve is a longitudinal cylindrical structure, including an inner hole. The shaft sleeve passes through the inner hole, and a flange is formed by bending outward at the upper end. The flange of the sleeve includes a longitudinal through hole, and a fastener passes through the through hole to be fixedly connected with the grinding motor, so that the grinding motor is installed at the upper end of the sleeve to obtain fixation and support. A rubber ring is fixedly installed on the lower surface of the flange of the sleeve, and contacts the upper surface of the adjusting wheel through the rubber ring to avoid impact, noise and damage. The rubber ring is an annular structure and has elasticity, capable of generating a buffering effect. Further, the lower end of the outer surface of the sleeve includes a lower thread, and the end cover is installed using the lower thread to provide fixation and support for the end cover.

[0022] The grinding motor is installed downward and includes a main shaft and a mounting seat. The main shaft is fixedly connected with the shaft sleeve to drive the grinding head installed at the lower end of the shaft sleeve for force-controlled universal floating grinding. The main shaft is a longitudinal round rod, and an external thread is included at the lower end. The main shaft is fixedly connected with the shaft sleeve through the external thread, so that the shaft sleeve is installed at the main shaft of the grinding motor at the upper end. The mounting seat is a horizontally placed disk-shaped structure and includes a longitudinal through hole. The through hole of the mounting seat and the through hole of the flange of the sleeve together pass through a fastener to be fixedly connected with the flange of the sleeve, so that the grinding motor is installed at the upper end of the sleeve using the mounting seat to obtain fixation and support.

[0023] The control motor includes an upward main shaft, which is installed upward on the lower surface of the upper-end flange of the housing. The main shaft of the control motor is connected with the wheel shaft of the support wheel serving as a driving wheel to drive the support wheel and drive and adjust the rotation angle of the adjusting wheel.

[0024] The end cover is an upward round cover-shaped structure, with an outer upper edge formed by bending upward at the outer edge, and radial ribs are included on the upper surface. The ribs are snapped into the axial groove at the lower end of the rubber spring to prevent the rubber spring from rotating relative to the end cover. The ribs are radial straight-bar structures and are connected to the outer upper edge of the end cover at the outer end, capable of increasing the structural strength. The diameter of the end cover is larger than the circumscribed circle diameter of the cross-sectional shape of the necking of the housing, preventing the end cover from entering the interior of the housing through the necking and preventing the rubber spring from being overcompressed and damaged. The end cover includes a through hole at the center, and an inner lower edge is formed by protruding downward at the edge of the through hole. A transverse screw hole is included on the inner lower edge. An internal thread is included on the inner surface of the through hole of the end cover, and the internal thread is matched with the lower thread at the lower end of the sleeve, so that the end cover is installed at the lower end of the sleeve using the through hole. The screw hole includes an internal thread, and a screw is installed using the internal thread, so that the screw abuts against the sleeve, having a locking effect to prevent the end cover from rotating relative to the sleeve to prevent the end cover from loosening and falling off.

[0025] The bushing is a longitudinal cylindrical structure, with an inner hole in the center. The upper end of the inner hole includes an internal thread, which is matched with the external thread of the main shaft of the grinding motor through the internal thread, so that the bushing is installed at the upper end on the main shaft of the grinding motor. The lower end of the outer surface of the bushing includes an external thread, and the lower end of the inner hole includes a tapered hole. A collet is installed by using the tapered hole, a nut is installed by using the external thread, and the shank of the grinding head is clamped by using the collet, so that the bushing is installed with the grinding head at the lower end. The tapered hole is a conical inner hole, the diameter of the lower end is larger than that of the upper end, and the upper end communicates with the inner hole of the bushing. The collet adopts a conical cylinder structure, the outer surface is conical, and includes an axial inner hole, also known as a spring collet. Radial through slots are included on the barrel wall, which can elastically contract inward and expand outward. The conical outer surface is matched with the tapered hole of the bushing, and the shank of the grinding head is inserted and clamped through the inner hole, so that the bushing is installed with the grinding head at the lower end. The nut includes a threaded hole, also known as a tool holder nut or a collet nut. The inner surface of the threaded hole includes an internal thread, which is matched with the external thread of the bushing through the internal thread, driving the collet to axially move and elastically contract inward, so that the collet clamps and fixes the shank of the grinding head.

[0026] The sheath is a longitudinal conical cylinder structure, with a circular upper mouth at the upper end and a circular lower mouth at the lower end; the diameter of the upper mouth is larger than that of the lower mouth, presenting a longitudinal conical cylinder structure. The upper mouth turns outwards, so that the sheath includes a flange at the upper end, and a clamp is installed below the flange, which can prevent the clamp from coming off. The sheath penetrates into the housing of the outer shell through its upper mouth, and by tightening the clamp, the upper end of the sheath is snapped into the groove of the housing, so that the sheath is installed at the upper end on the housing of the outer shell, preventing the sheath from loosening or falling off. The lower end of the sheath is inwardly retracted, and the inner lower edge of the end cover passes through its lower mouth. The outer surface of the sheath is corrugated, which can elastically expand and contract longitudinally, so that the lower end of the sheath tightly adheres to the lower surface of the end cover upwards, preventing chips and dust from invading, ensuring that the rubber spring can freely expand and contract, and having a protective effect.

[0027] An intelligent universal floating control method is used for a robot equipped with the grinding device of the present invention to perform universal floating force control grinding. The following operation models are established and stored in the control system of the robot in the control method, preferably established before leaving the factory.

[0028] First, the grinding device is produced by customization. The model numbers of the workpiece blanks that the customer needs to grind and process are numbered and recorded as m ; when the robot performs grinding and processing, point position control is carried out with the grinding head as the reference. Therefore, the position coordinates of the reference point of the grinding head are recorded as ( x, y, z ); where x is the abscissa,y is the vertical coordinate, z is the vertical coordinate. The model of the workpiece blank refers to the classification based on the structural characteristics, forming method, specifications, and dimensions of the workpiece blank; thus, workpiece blanks with the same structural characteristics, forming method, specifications, and dimensions have the same number m ; the specifications refer to the tolerance, material, and surface quality of the workpiece blank; the dimensions refer to the dimensional characteristics such as the length, width, thickness, and diameter of the workpiece blank; The control motor of the grinding device can drive and adjust the rotation angle of the adjusting wheel, and through the eccentric through-hole of the adjusting wheel, adjust and limit the horizontal position of the upper part of the sleeve, and control the horizontal position of the reference point of the grinding head; therefore, the rotation angle of the control motor is denoted as θ . When conducting the grinding processing experiment, the grinding device installs a force sensor using the mounting cylinder of the housing, and then installs it on the manipulator of the robot through the force sensor; the cutting force obtained by the force sensor is denoted as f ; Open a storage space in the storage medium of the robot control system to record and store θ ( i, m, x, y, z ) and f ( i, m, x, y, z ); among them, i is the coordinate serial number; θ ( i, m, x, y, z ) is the rotation angle of the control motor when the reference point of the grinding head reaches the m th position with the coordinate of ( i ) during the grinding process of the workpiece blank with the grinding processing number x, y, z , and the initial value is 0°; f ( i, m, x, y, z ) is the cutting force value obtained by the force sensor when the reference point of the grinding head reaches the m th position with the coordinate of ( i ) during the grinding process of the workpiece blank with the grinding processing number x, y, z .

[0029] Second, write a processing program for the workpiece blank with the number m to obtain the processing route and related processing parameters, at least including the coordinate sequence { i , m , x , y , z} where the reference point of the grinding head moves during the processing. The processing program is stored in the storage medium of the robot control system. To avoid programming errors, it is preferably to conduct a first-piece trial cut.

[0030] Third, use a robot installed with the grinding device to conduct a grinding experiment on the workpiece blank numbered m , observe the grinding effect and record f ( i , m , x , y , z ), and obtain the maximum and minimum cutting forces, denoted as maxf ( m ) and minf ( m ).

[0031] Fourth, use a robot installed with the grinding device to continue conducting multiple grinding experiments on the workpiece blank numbered m , adjust θ ( i , m , x , y , z ), replace the rubber spring to reduce the value of ( maxf ( m ) - minf ( m )) and improve the control accuracy, enhance the grinding effect, and improve the processing efficiency. When the cutting force is insufficient, it is preferred to replace the rubber spring with a larger elastic modulus and free length; a rubber spring with a larger elastic modulus can generate a greater elastic force when being squeezed and deformed; a rubber spring with a larger free length can generate a greater pre-tightening force after installation.

[0032] The control method includes the following steps: First step, the robot installed with the grinding device conducts grinding on the workpiece blank numbered m . Before the grinding starts, the control system of the robot starts and initializes, sets the initial value of i to 0; sets variables tempx , tempy and tempz , and sets their initial values to the values of m , x , y , z in x , y and z respectively; the control system of the robot issues a control instruction to adjust the rotation angle of the control motor to 0°.

[0033] Second step, the robot starts the grinding operation on the workpiece blank numbered m ; the grinding motor starts.

[0034] In the third step, the control system of the robot controls the movement of the grinding head, and the reference point of the grinding head moves, and its coordinates { x , y , z} change; Judge whether the reference point of the grinding head reaches the i th coordinate point; if ([[]] tempx == x and tempy == y and tempz = =z ) is true, then it reaches; otherwise it does not reach.

[0035] In the fourth step, if it reaches, then: {The control system of the robot issues a control instruction to adjust the rotation angle of the control motor to θ ( i , m , x , y , z ) to ensure the required grinding effect and processing efficiency; i = i +1; Set the values of the variables tempx , tempy and tempz to be { i , m , x , y , z} in x , y and z ; Go to the third step}.

[0036] In the fifth step, judge whether the processing is finished. If not, go to the third step; The grinding motor stops; End.

[0037] Supplementary description: (1) The support wheel is installed on the housing and the cover through its wheel shaft and can rotate relatively; there are at least three support wheels, and their teeth are engaged with the teeth of the adjusting wheel to support and limit the lateral position of the adjusting wheel. The adjusting wheel includes an eccentric through hole, and the sleeve passes through the eccentric through hole and has a clearance fit with it and can rotate relatively. Therefore, the support wheel can drive the adjusting wheel to adjust its rotation angle by adjusting its rotation angle, and adjust and limit the lateral position of the upper part of the sleeve relative to the housing.

[0038] (2) A sealing ring is fixedly installed on the upper surface of the adjusting wheel. The sealing ring abuts against the protective cover installed on the housing to achieve dynamic sealing. The rubber spring passes through the sleeve with its inner hole, abuts against the lower surface of the adjusting wheel at the upper end, and abuts against the upper surface of the end cover at the lower end to bear the compression force. The end cover is installed at the lower end of the outer surface of the sleeve. The protective sheath can elastically expand and contract longitudinally, is installed at the upper end on the housing of the outer shell, and tightly adheres to the lower surface of the end cover at the lower end to prevent chips and dust from invading.

[0039] Therefore, there is a gap between the lower surface of the adjusting wheel and the upper surface of the flange of the housing, which can effectively avoid contact and wear. In addition, during the grinding operation process, the grinding head installed on the bushing contacts the workpiece blank located below the housing, generating a feed reaction force, which can cause the rubber spring to compress and increase the acting force generated by the abutment on the lower surface of the adjusting wheel. Therefore, the feed reaction force generated during the grinding operation process with the workpiece blank can cause the adjusting wheel to maintain a gap between the lower surface and the upper surface of the flange of the housing, avoiding contact and wear.

[0040] (3) The bushing is installed on the main shaft of the grinding motor at the upper end and a grinding head is installed at the lower end. The grinding motor is installed on the upper end of the sleeve by using the mounting seat. The sleeve is a longitudinal cylindrical structure, passes through the bushing with its inner hole, and the end cover is installed at the lower end of the outer surface. The sleeve forms a flange at the upper end, and a rubber ring is fixedly installed on the lower surface of the flange, and contacts the adjusting wheel through the rubber ring. The rubber spring passes through the sleeve with its inner hole, abuts against the lower surface of the adjusting wheel at the upper end, and abuts against the upper surface of the end cover at the lower end to bear the compression force. Therefore, during the grinding operation process, the grinding head installed on the bushing contacts the workpiece blank located below the housing, generating a feed reaction force, which can cause the rubber spring to compress and achieve floating grinding in the longitudinal movement dimension.

[0041] (4)The lower end of the housing is closed by a longitudinal non-circular through-hole. The rubber spring is fitted with the lower-end closing of the housing on the lower part of its outer surface, enabling the rubber spring to pass through the closing and freely expand and contract, so as to define the lateral position of the rubber spring and the sleeve at the lower part and prevent relative rotation. The housing is connected to the sleeve on which the grinding motor is installed through the rubber spring at the lower-end closing. In addition, the rubber spring has axial grooves on its lower end face and is fitted with the end cover by using the axial grooves to prevent the rubber spring from rotating relative to the end cover. During the grinding operation, the grinding head installed on the bushing contacts the workpiece blank located below the housing, and the grinding motor rotates to generate a cutting torque. Therefore, the lower end of the housing can resist the cutting torque through the rubber spring, which can cause the rubber spring to produce torsional deformation and achieve floating grinding in the longitudinal rotation dimension.

[0042] (5)The housing is connected to the sleeve on which the grinding motor is installed through the rubber spring at the lower-end closing; the sleeve passes through the eccentric through-hole of the adjusting wheel at the upper part and has a clearance fit with it. Therefore, during the grinding operation, the housing can resist the lateral movement and lateral torsion effects generated by the vibration of the grinding head through the rubber spring at the lower end; the housing restricts the six degrees of freedom of the reference point of the grinding head through the rubber spring, and can achieve force-controlled universal floating grinding.

[0043] (6)Preferably before leaving the factory, for different models of workpiece blanks that the customer needs to grind, the control method of the present invention establishes an operation model, stores the rotation angles of the control motor when the reference point of the grinding head reaches different positions with coordinates of ( x , y , z ); writes a processing program, conducts a grinding experiment, adjusts θ ( i , m , x , y , z ), replaces the rubber spring to reduce the value of ( maxf ( m ) - minf ( m )) to improve the control accuracy, enhance the grinding effect, and improve the processing efficiency. In the third step of the control method, it is judged whether the reference point of the grinding head reaches the i th coordinate point stored in the operation model; if it reaches, then in the fourth step, the rotation angle of the control motor is adjusted to θ ( i , m , x , y , z) to ensure the required grinding effect and processing efficiency. Therefore, the control method utilizes processing experiments to preferably select rubber springs and optimize the rotation angle of the control motor when the grinding head reaches different positions. The optimal selection of the rubber springs can generate optimal elastic force and pre-tightening force to adapt to different models of workpiece blanks that customers need to grind and process. Optimizing the rotation angle of the control motor when the grinding head reaches different positions can actively regulate the cutting force horizontally, achieve active force control horizontally, improve the control accuracy, and make up for the shortcomings of the rubber springs with relatively small lateral floating amount and insufficient passive force control horizontally. The rubber springs are longitudinally cylindrical structures; therefore, relative to the longitudinal direction, the grinding device has a relatively small lateral floating amount and insufficient passive force control horizontally.

[0044] The control method utilizes processing experiments to preferably select rubber springs to adapt to different models of workpiece blanks that customers need to grind and process; and optimizes the rotation angle of the control motor when the grinding head reaches different positions to improve the control accuracy and meet the grinding effect and processing efficiency of different structural characteristics of the workpiece blanks. During grinding and processing, only the rotation angle of the control motor stored in the operation model is called according to the position of the grinding head; without using a sensor for active force control, the combination of active force control and passive force control can be achieved, and the technical contradiction of "complicated active force control, high precision and cost; simple passive force control, low precision and cost" can be solved. Since workpieces of the same model have the same structural characteristics, forming methods, specifications and dimensions, the control method preferably establishes and stores an operation model before leaving the factory, writes and stores a processing program, and only by preferably selecting rubber springs and optimizing the rotation angle of the control motor when the grinding head reaches different positions, realizes force-controlled universal floating grinding to adapt to the tolerance and surface quality changes of the workpiece blanks at the processing site. Therefore, during the grinding and processing process, the control method no longer uses a sensor to regulate the movement route and processing parameters of the grinding head and does not adopt closed-loop control, greatly reducing the difficulty and cost of active force control and improving the control accuracy.

[0045] The beneficial effects of the present invention are as follows: (1) The bushing of the present invention is installed on the main shaft of the grinding motor at the upper end and a grinding head at the lower end; the grinding motor is installed on the upper end of the sleeve by using the mounting seat; the sleeve is a longitudinally cylindrical structure, and its inner hole passes through the bushing, and the end cover is installed at the lower end of the outer surface; the rubber spring passes through the sleeve with its inner hole, abuts against the lower surface of the adjusting wheel at the upper end, and abuts against the upper surface of the end cover at the lower end, bearing the compression effect.

[0046] In addition, the support wheels are mounted on the housing and the protective cover through their axles and can rotate relatively; there are at least three support wheels, which are meshed with the teeth of the adjusting wheel through their teeth to support and define the lateral position of the adjusting wheel. The adjusting wheel includes an eccentric through hole, and the sleeve passes through the eccentric through hole and is in clearance fit with it, and can rotate relatively. The control motor of the grinding device can drive and adjust the rotation angle of the adjusting wheel, and through the eccentric through hole of the adjusting wheel, adjust and define the lateral position of the upper part of the sleeve, and regulate the lateral position of the reference point of the grinding head. The necking at the lower end of the housing is connected to the sleeve mounting the grinding motor through the rubber spring.

[0047] It can be seen that the integrally mounted sleeve and grinding motor are connected to the housing, the protective cover, the adjusting wheel, and the support wheel mounted together through the rubber spring; during the grinding operation process, the housing of the outer shell resists the feed reaction force, the cutting torque, the lateral movement and lateral torsion of the grinding head caused by vibration through the rubber spring; the housing of the outer shell restricts the six degrees of freedom of the reference point of the grinding head through the rubber spring, and can realize force-controlled universal floating grinding. Therefore, compared with the existing multi-dimensional force-controlled floating grinding technology, the outer shell of the grinding device of the present invention restricts the six degrees of freedom of the reference point of the grinding head through the rubber spring, and can realize force-controlled universal floating grinding; the grinding device of the present invention does not need to use precision parts such as spherical bearings, has a simple structure and low cost.

[0048] In addition, the rubber spring of the present invention includes a cylindrical helical steel wire inside and is wrapped with rubber around the steel wire, also known as a composite spring. Therefore, compared with the existing floating tool shanks using metal springs, the grinding device of the present invention can bear multi-directional loads simultaneously and realize universal floating; it can absorb vibration energy and avoid generating noise, so the shock absorption, vibration reduction and noise reduction effects are good; it has strong bearing capacity, stable operation and long service life.

[0049] (2) The control motor of the grinding device of the present invention is connected to the axle of the support wheel as the driving wheel to drive the support wheel, drive and adjust the rotation angle of the adjusting wheel; and through the eccentric through hole of the adjusting wheel, adjust and define the lateral position of the upper part of the sleeve, and regulate the lateral position of the reference point of the grinding head. Therefore, the grinding device of the present invention can realize force-controlled universal floating grinding only by adjusting the rotation angle of the control motor; utilize the one-dimensional rotational motion of the control motor to regulate the multi-dimensional motion of the reference point of the grinding head. Compared with the existing force control devices using hydraulic, electromagnetic and pneumatic principles, the grinding device of the present invention has strong control ability, simple control principle, few control links and few components, so it has a simple structure and low cost.

[0050] In addition, the rubber spring of the present invention is a longitudinal cylindrical structure; relative to the longitudinal direction, the floating amount of the grinding device in the transverse direction is small, and the passive force control in the transverse direction is insufficient. The grinding device of the present invention utilizes the rotational movement of the control motor to adjust and define the transverse position of the upper part of the sleeve, achieving active force control in the transverse direction and improving the control accuracy; it can compensate for the disadvantages of the small floating amount of the rubber spring in the transverse direction and the insufficient passive force control in the transverse direction.

[0051] (3) The rubber spring passes through the sleeve with its inner hole, abuts against the lower surface of the adjusting wheel at the upper end, and preferably uses its lip to snap into the gap between the sleeve and the flared opening of the eccentric through-hole of the adjusting wheel to ensure its clearance fit and uniform clearance. The grinding device of the present invention utilizes the control motor to regulate the transverse position of the upper part of the sleeve, and also simultaneously regulates the transverse position of the upper end of the rubber spring. The grinding device of the present invention achieves active force control in the transverse direction and utilizes the rubber spring to achieve universal floating grinding. Therefore, the grinding device of the present invention combines active force control and passive force control by using the rubber spring, solving the technical contradiction of "complicated active force control, high precision and cost; simple passive force control, low precision and cost".

[0052] In addition, the adjusting wheel of the present invention regulates the transverse position of the upper end of the rubber spring, only regulates the transverse position of the upper part of the sleeve, does not limit the position of the upper end of the sleeve, and does not affect the longitudinal movement of the sleeve. Therefore, the grinding device of the present invention combines active force control and passive force control by using the rubber spring, with a large regulation and floating range.

[0053] (4) The control method of the present invention preferably establishes an operation model before leaving the factory, stores the rotation angles of the control motor when the reference point of the grinding head reaches different positions; writes a machining program and conducts a grinding machining experiment. The control method preferably selects the rubber spring by using the machining experiment and optimizes the rotation angle of the control motor when the grinding head reaches different positions; preferably selecting the rubber spring can generate the optimal elastic force and pre-tightening force to adapt to different types of workpiece blanks that the customer needs to grind and process; optimizing the rotation angle of the control motor when the grinding head reaches different positions can actively regulate the cutting force in the transverse direction and improve the control accuracy; it can compensate for the disadvantages of the small floating amount of the rubber spring in the transverse direction and the insufficient passive force control in the transverse direction.

[0054] Therefore, compared with the existing multi-dimensional force control technology, the control method of the present invention uses the method of processing experiments to adapt to different types of workpiece blanks that customers need to grind and process, and optimizes the control of the rotation angle of the motor when the grinding head reaches different positions, improving the control accuracy and meeting the grinding effect and processing efficiency of different structural characteristics of the workpiece blanks. During grinding and processing, only the rotation angle of the control motor stored in the operation model is called according to the position of the grinding head. Without using a sensor for active force control, the combination of active force control and passive force control can be achieved, solving the technical contradiction of "active force control is complex, with high precision and cost; passive force control is simple, with low precision and cost".

[0055] (5)The control method of the present invention only through processing experiments, preferably selects rubber springs, and optimizes the control of the rotation angle of the motor when the grinding head reaches different positions, realizing force-controlled universal floating grinding to adapt to the tolerance and surface quality changes of the workpiece blank at the processing part. Compared with the existing multi-dimensional force control technology, during the grinding and processing process, the control method no longer uses a sensor to regulate the movement route and processing parameters of the grinding head, and does not adopt closed-loop control, greatly reducing the difficulty and cost of active force control and improving the control accuracy.

[0056] In addition, the control method of the present invention adopts open-loop control and is integrated into the control system of the robot, which can reduce the development difficulty; the control method establishes an operation model through processing experiments, simplifies the control process during processing, opens up a new channel for intelligent control in the field of force-controlled grinding technology, can promote the intelligent development of grinding robots, and also promotes the application and development of the new generation of information technology.

[0057] (6)The workpiece blanks of specific manufacturing enterprises are of a single type, and the grinding robots used are generally targeted at specific scenarios. Therefore, the grinding device of the present invention establishes and stores an operation model for different types of workpiece blanks of customers, writes and stores processing programs, and conducts grinding processing experiments; adopts customized production for specific customers, which can improve the control accuracy, enhance the grinding effect, improve the processing efficiency, and increase customer satisfaction. The present invention discovers and makes full use of the characteristic that the workpiece blanks that need to be ground and processed by specific manufacturing enterprises are of a single type, which can reduce production and operation risks and increase economic and social benefits. Description of the Drawings

[0058] Figure 1 is the overall structural schematic diagram of the grinding device; Figure 2 is Figure 1 the partial enlarged view of the dotted circle part in; Figure 3 is the rubber spring 2 at Figure 1 the bottom view of the position; Figure 4 is the housing 11 atFigure 1 A top view of the location; Figure 5 It is a schematic diagram of the cooperation principle between the adjusting wheel 13 and the supporting wheel 14.

[0059] Explanation of the accompanying drawings: outer shell 1, shell 11, protective cover 12, annular groove 121, adjusting wheel 13, sealing ring 131, eccentric through hole 132, supporting wheel 14, groove 15, axial hole 16, closing 17, fastening hole 18, mounting tube 19, rubber spring 2, steel wire 21, chamfered surface 22, axial groove 23, sleeve 3, rubber ring 31, lower thread 32, grinding motor 4, spindle 41, mounting seat 42, control motor 5, end cover 6, rib 61, screw 62, screw hole 63, internal thread 64, sleeve 7, external thread 71, tapered hole 72, sleeve 8, clamp 81. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods: the orientation described in this specification is based on the working position of the grinding device; the vertical direction is the longitudinal direction, and the direction perpendicular to the longitudinal direction is the transverse direction; other directions are similar. Figure 1 In the diagram, the up-down direction is the vertical direction, and the other directions are similar. Figure 1 The overall structure diagram of the grinding device includes a housing 1, a rubber spring 2, a sleeve 3, a grinding motor 4, a control motor 5, an end cover 6, a sleeve 7 and a sleeve 8; the grinding head is a universal standard part, and there is no Figure 1 Draw in; Figure 2 for Figure 1 A partial enlarged view of the area indicated by the dotted circle.

[0061] The housing 11 is an upright cylindrical structure, which is inwardly contracted at the lower part and includes a surrounding groove 15 at the lower part of the outer surface; the housing 11 is inwardly contracted at the lower end to form a closing mouth 17, and is convex at the upper end to form a flat flange; the housing 11 and its above-mentioned structural features are preferably formed by die-casting of aluminum alloy material. The longitudinal shaft hole 16 and the fastening hole 18 included in the housing 11 on the flange are preferably formed by cutting.

[0062] The protective cover 12 is an oblong cover, with the outer edge bent downward to form a lower edge, and a longitudinally through-hole in the middle, wherein the lower surface of the hole edge includes a circular annular groove 121; the protective cover 12 and the above-mentioned structural features are preferably formed by forging an aluminum alloy sheet. The protective cover 12 includes a through hole at a lateral position corresponding to the fastening hole 18 of the housing 11, and an axial hole at a lateral position corresponding to the axial hole 16 of the housing 11; the through hole and the axial hole of the protective cover 12 are preferably formed by cutting.

[0063] The adjusting wheel 13 is a disc-shaped gear, with teeth on its outer circumferential surface, and includes a circular eccentric through-hole 132, and the eccentric through-hole 132 preferably has an enlarged diameter at the lower end to form a flared opening; the adjusting wheel 13, its teeth, the eccentric through-hole 132, and the flared opening at the lower end of the eccentric through-hole 132 are preferably formed by machining an aluminum alloy plate. A circular sealing ring 131 is fixedly installed outside the upper surface of the adjusting wheel 13; the sealing ring 131 is a circular structure and has elasticity, and is preferably realized by an existing sealing ring product. The fixed installation of the sealing ring 131 outside the upper surface of the adjusting wheel 13 is preferably by bonding with an existing resin glue.

[0064] The supporting wheel 14 is a disc-shaped gear, includes a longitudinal axle in the center, and has teeth on its outer circumferential surface; the supporting wheel 14 and its above structural features are formed by using the materials and processes of existing gears, and engineering plastics, aluminum alloy or stainless steel materials are preferred. The installation cylinder 19 is a horizontal cylinder, is fixedly connected to the outer side surface of the housing 11 at the right end to become an integral body, and includes a flange at the left end; it is preferably made of the same material as the housing 11 and is integrally die-cast. The through-hole included in the flange of the installation cylinder 19 is preferably formed by machining.

[0065] Figure 3 For the rubber spring 2 at Figure 1 The bottom view of the position shows the structural features of its lower end surface, and the dotted line in the figure represents the cylindrical helical steel wire 21 included inside. The rubber spring 2 is a longitudinal straight cylindrical structure, includes a circular inner hole, and bears compression; the rubber spring 2 preferably protrudes upward at the upper end of the inner hole to form a lip. The rubber spring 2 includes a cylindrical helical steel wire 21 inside, and rubber is wrapped around the steel wire 21; the rubber spring 2 has plane cuts 22 evenly distributed along the circumference on its outer surface, presenting a non-circular cross-section; and has an axial groove 23 on the lower end surface. The rubber spring 2 and its above structural features are preferably formed by using the materials and processes of existing composite springs, and can also be realized by selecting existing composite spring products.

[0066] As Figure 1 and Figure 2 As shown, the sleeve 3 is a longitudinal cylindrical structure, includes an inner hole, and forms a flange at the upper end, and is preferably formed by forging an aluminum alloy pipe. The lower thread 32 included at the lower end of the outer surface of the sleeve 3 is preferably formed by machining. The rubber ring 31 is a circular structure and has elasticity, and is preferably realized by an existing rubber ring product; the fixed installation of the rubber ring 31 on the lower surface of the flange of the sleeve 3 is preferably by bonding with an existing resin glue.

[0067] As Figure 1As shown, the grinding motor 4 includes a main shaft 41 and a mounting base 42, preferably realized by using existing motor products. The external thread included at the lower end of the main shaft 41 is preferably formed by cutting. The control motor 5 includes an upward main shaft, drives the support wheel 14, and drives and adjusts the rotation angle of the adjusting wheel 13, preferably realized by using existing servo motor products. The main shaft of the control motor 5 is connected to the axle of the support wheel 14 which serves as a driving wheel. Preferably, the main shaft of the control motor 5 is directly used as the axle of the support wheel 14 to be connected to the support wheel 14; and preferably, it is mechanically connected to facilitate disassembly, assembly and maintenance. The installation of the control motor 5 on the lower surface of the flange of the housing 11 is preferably realized by using well-known fasteners to facilitate disassembly, assembly and maintenance.

[0068] As Figure 1 and Figure 2 As shown, the end cover 6 is a circular cover-shaped structure facing upward, with an outer upper edge formed at the outer edge and radial ribs 61 on the upper surface; the ribs 61 are radial straight bar-shaped structures and are connected to the outer upper edge of the end cover 6 at the outer ends; the end cover 6 includes a through hole in the center and an inner lower edge is formed at the edge of the through hole; the end cover 6 and its above-mentioned structural features are preferably formed by die-casting of aluminum alloy materials. The transverse screw holes 63 and their internal threads included in the end cover 6, and the internal threads 64 included on the inner surface of the through hole are all preferably formed by cutting. The screw holes 63 are used to install screws 62 with their internal threads; the screws 62 are preferably realized by using existing set screw standard parts.

[0069] As Figure 1 As shown, the bushing 7 is a longitudinal cylindrical structure, includes an inner hole in the center, has an internal thread at the upper end of the inner hole, has an external thread 71 at the lower end of the outer surface, and has a tapered hole 72 at the lower end of the inner hole, preferably formed by cutting an aluminum alloy pipe. The bushing 7 installs a spring collet by using the tapered hole 72, installs a nut by using the external thread 71, and clamps the shank of the grinding head by using the spring collet, so that the bushing 7 installs the grinding head at the lower end.

[0070] The spring collet has a conical barrel structure with a conical outer surface, includes an axial inner hole, and has radial through slots on the barrel wall, enabling elastic inward contraction and outward expansion. It is fitted with the tapered hole 72 of the sleeve 7 through the conical outer surface, and the shank of the grinding head is inserted and clamped through the inner hole. It is preferably realized by using an existing spring chuck product. The nut includes a threaded hole, and the inner surface of the threaded hole has an internal thread, which is fitted with the external thread 71 of the sleeve 7 to drive the spring collet to move axially and elastically contract, so that the spring collet clamps and fixes the shank of the grinding head; the nut is preferably realized by using an existing tool holder nut or collet nut product. The grinding head includes a head and a shank. The head has hard abrasives or cutting teeth on its surface; the shank has a straight rod structure for clamping and is also called a tool holder; the grinding head is preferably realized by using a well-known grinding head or file head product according to the material of the workpiece blank to be ground and the structural characteristics of the processing part.

[0071] As Figure 1 shown, the sheath 8 has a longitudinal conical barrel structure, has a circular upper opening at the upper end, a circular lower opening at the lower end, has a flanging at the upper end, and has a corrugated shape on the outer surface, enabling elastic longitudinal expansion and contraction. It is preferably realized by using an existing corrugated expansion rubber sleeve product. The sheath 8 is installed with a clamp 81 below the flanging; the clamp 81 is preferably realized by using an existing stainless steel clamp product to facilitate fastening, installation, disassembly, and maintenance.

[0072] Figure 4 is the top view of the housing 11 at the Figure 1 position, expressing the structural characteristics of the flat flange formed by the outward protrusion at the upper end of the housing 11. The oblong cover 12 is fastened to the housing 11 by abutting the lower edge against the upper surface of the outer edge of the flange of the housing 11, so the flange of the housing 11 is oblong. At Figure 4 the described embodiment, the upper surface of the outer edge of the flange of the housing 11 is preferably subjected to grinding processing to facilitate the cooperation with the lower edge of the cover 12. At Figure 4 the described embodiment, there are four holes around the shaft hole 16 for passing through fasteners to realize the installation of the control motor 5 on the lower surface of the flange of the housing 11. In addition, the flanges of the cover 12 and the housing 11 are preferably further changed and optimized in shape to facilitate lightweighting.

[0073] At Figure 4In the illustrated embodiment, the cross-sectional shape of the necking 17 is a closed figure formed by the intersection of a concentric equilateral triangle and a circle, which includes three circular arcs and three line segments evenly distributed along the circumference. The necking 17 passes through the lower part of the rubber spring 2 and mates with the lower part of the outer surface of the rubber spring 2 to avoid relative rotation. Therefore, it is only a preferred embodiment that the outer surface of the rubber spring 2 includes the flattened planes 22 evenly distributed along the circumference. The necking 17 and the rubber spring 2 may also adopt other structural features that can cooperate with each other and avoid relative rotation.

[0074] Figure 5 FIG. is a schematic diagram of the cooperation principle between the adjusting wheel 13 and the supporting wheel 14, which shows the relative positional relationship in the horizontal direction among the adjusting wheel 13, the supporting wheel 14 and the flange of the housing 11. Figure 5 The structure of the flange of the housing 11 is expressed by double-dashed lines; the cylindrical inner wall of the housing 11 extends upward to form the circular inner edge of the flange of the housing 11. The flange of the housing 11 is offset to the right relative to the cylinder of the housing 11, wider on the right and narrower on the left, so as to facilitate the installation of the control motor 5 on the lower surface on the right side to avoid interference. The diameter of the adjusting wheel 13 is larger than the inner diameter of the cylinder of the housing 11, that is, larger than the diameter of the inner edge of the flange of the housing 11, to realize the longitudinal limit of the adjusting wheel 13 and prevent the adjusting wheel 13 from falling into the cylinder of the housing 11. The adjusting wheel 13 is eccentric to the right relative to the circular inner edge of the flange of the housing 11, and the eccentric through hole 132 of the adjusting wheel 13 is eccentric relative to the adjusting wheel 13; this can increase the eccentricity of the eccentric through hole 132 relative to the inner edge of the flange of the housing 11, that is, increase the eccentricity relative to the inner wall of the cylinder of the housing 11, so as to increase the adjustment range of the grinding device in the horizontal direction. During the design implementation, the wall thickness of the rubber spring 2 should be considered to avoid interference.

[0075] Preferably, before leaving the factory, an operation model is established and stored in the control system of the robot for the control method. The grinding device is produced by customization, and the number of the workpiece blank model that the customer needs to grind and process is recorded as m . The existing grinding robot includes a fuselage, a large arm, a small arm, a manipulator and a control system, and a control program is stored in the control system; the control program preferably performs point control based on the position of the grinding head to form a processing program including the processing route and related processing parameters; the processing route is preferably expressed based on the reference point position of the grinding head and at least includes the coordinate sequence { i , m , x , y , z}。The reference point of the grinding head is preferably the rotation center of the head of the grinding head close to the cutting position. During the implementation of the machining program, according to the tool compensation method of the existing numerical control program, the cutting position is calculated based on the structural characteristics of the workpiece blank at the machining site, that is, the contact position between the grinding head and the workpiece blank. The relevant machining parameters at least include technical parameters related to cutting machining such as cutting force, cutting speed, and feed rate, all of which adopt existing machining technologies and will not be elaborated in detail.

[0076] The control method records the rotation angle of the control motor 5 as θ ; θ Preferably, the connecting line position between the spindle axis of the control motor 5 and the axis of the adjusting wheel 13 in the transverse plane is used as the reference, that is, as 0°; as Figure 4 shown, the cylindrical axis of the housing 11, the axis of the mounting cylinder 19, the axis of the adjusting wheel 13, and the axis of the spindle of the control motor 5 are preferably in the same longitudinal plane.

[0077] When the control method conducts a grinding experiment, the grinding device installs a force sensor using the mounting cylinder 19 of the housing 1, and then installs it on the manipulator of the robot through the force sensor; the force sensor is preferably realized by a known six-dimensional force sensor. The cutting force obtained by the force sensor f ( i , m , x , y , z ) is preferably the sensor value of the dimension with the largest numerical change obtained in the grinding experiment. When the reference point of the grinding head reaches the i th coordinate of ([[]] x , y , z ), the structural characteristics of the workpiece blank to be machined make the dimension with the largest change in the sensor value express the most sensitive change in the cutting force value; it is also possible to comprehensively calculate the sensor values of multi-dimensional changes using mathematical methods. When performing grinding, due to the removal of the force sensor, the change in the structural dimensions of the robot, and the change in the clamping position of the workpiece blank, etc., the machining route needs to be adjusted, which is realized based on existing programming technologies and machining technologies and will not be elaborated in detail; after adjustment and change, it is preferably to conduct a first-piece trial cut to ensure safety.

[0078] When the control method conducts multiple grinding experiments on the workpiece blank numbered m , it is necessary to conduct multiple grinding experiments on the same workpiece blank and also conduct multiple grinding experiments on different workpiece blanks with the same number m . In order to improve the control accuracy, enhance the grinding effect, and improve the machining efficiency, through multiple grinding experiments, the rubber spring 2 is preferably optimized, and θ (i , m , x , y , z ) When, it is preferred to write an intelligent control program for human-machine collaborative operation; and it is preferred to utilize artificial intelligence, big data and other new generation information technologies to extract and accumulate relevant knowledge.

[0079] For the control method of the present invention, for the workpiece blank model that the customer needs to polish and process, the polishing device is customized and produced. The types of workpiece blanks of a specific manufacturing enterprise are single, that is, the number of workpiece blank models for polishing and processing by an enterprise is very small; a polishing robot is only used to polish one or several models of workpiece blanks. Therefore, the workload of adjusting the processing program and the polishing device is very small. The adjustment of the polishing device preferably replaces the rubber spring 2 of the polishing device in the machine, and it is not necessary to replace the polishing device as a whole, which is simple and convenient. When replacing the rubber spring 2, it is only necessary to disassemble the sheath 8, the end cover 6 and the polishing head in the machine for replacement, which is simple and convenient. It is not necessary to disassemble the polishing device as a whole from the robot manipulator, and it is also convenient for automated operation, which can promote the application and development of service robots.

[0080] The control method opens up a storage space in the storage medium of the robot control system, establishes and stores an operation model, writes and stores a processing program, all of which are based on the development technology of existing industrial robots and are implemented using existing programming software; the start-stop control of the polishing motor 4 and the rotation angle regulation of the control motor 5 are all realized based on the development technology of existing industrial robots, and will not be elaborated in detail.

[0081] The above embodiments are only the preferred embodiments of the present invention and do not constitute a limitation to the present invention. Under the conditions of meeting the structural and performance requirements of the present invention, changing the materials and manufacturing processes are all within the protection scope of the present invention.

Claims

1. A force-controlled universal floating grinding device for a robot, comprising a grinding head, characterized in that: It includes a housing (1), a rubber spring (2), a sleeve (3), a grinding motor (4), a control motor (5), an end cover (6), and a bushing (7). It is installed on the manipulator of the robot through the housing (1), the grinding head is installed through the bushing (7), and universal floating force control is performed through the rubber spring (2) and the control motor (5) to achieve force-controlled universal floating grinding of the workpiece blank; The housing (1) includes a cylindrical housing (11) and a mounting cylinder (19) that are perpendicular to each other, and is installed on the manipulator of the robot through the mounting cylinder (19); The housing (1) installs an adjusting wheel (13) and a supporting wheel (14) on the housing (11). The upper end of the rubber spring (2) is pressed through the adjusting wheel (13), and the supporting wheel (14) meshes with the adjusting wheel (13) to support the adjusting wheel (13) and adjust its rotation angle, so as to adjust and define the lateral position of the upper end of the rubber spring (2) and the upper part of the sleeve (3); The adjusting wheel (13) includes a circular eccentric through hole (132). The sleeve (3) passes through the eccentric through hole (132) at the upper part. The adjusting wheel (13) can rotate relative to the sleeve (3); so that the adjusting wheel (13) can adjust and define the lateral position of the upper part of the sleeve (3); The housing (11) is a vertical cylindrical structure, and a necking (17) is formed at the lower end; so that the rubber spring (2) passes through the necking (17), and the rubber spring (2) can freely expand and contract; The necking (17) is a longitudinal non-circular through hole, which cooperates with the lower part of the outer surface of the rubber spring (2) to define the lateral position of the rubber spring (2) and the sleeve (3) at the lower part, and prevent the rubber spring (2) from rotating relative to the housing (11); The rubber spring (2) is a longitudinal straight cylindrical structure, including an inner hole, and the sleeve (3) passes through the inner hole; the rubber spring (2) abuts against the adjusting wheel (13) at the upper end and abuts against the end cover (6) at the lower end, and bears the compression effect; The sleeve (3) is a longitudinal cylindrical structure, including an inner hole, and the bushing (7) passes through the inner hole; The grinding motor (4) is installed at the upper end of the sleeve (3); the grinding motor (4) includes a main shaft (41), and is fixedly connected to the bushing (7) through the main shaft (41) to drive the grinding head for force-controlled universal floating grinding; The control motor (5) is installed on the housing (11); the control motor (5) is connected to the supporting wheel (14), drives the supporting wheel (14), and drives and adjusts the rotation angle of the adjusting wheel (13); The end cover (6) is an upwardly facing circular cover structure, and includes a through hole in the center. It is installed at the lower end of the sleeve (3) through the through hole to prevent the end cover (6) from rotating relative to the sleeve (3).

2. The force control universal floating grinding device for a robot according to claim 1, wherein: The rubber spring (2) includes an axial groove (23) on the lower end face; The end cap (6) includes radial ribs (61) on the upper surface. By using these ribs (61) to snap into the axial groove (23) at the lower end of the rubber spring (2), rotation of the rubber spring (2) relative to the end cap (6) is avoided. The end cap (6) forms an inner lower edge at the edge of the through hole, and includes a transverse screw hole (63) on the inner lower edge. The screw hole (63) includes internal threads, and a screw (62) is installed using these internal threads such that the screw (62) abuts against the sleeve (3), providing a locking function to prevent the end cap (6) from rotating relative to the sleeve (3).

3. A force control universal floating grinding device for a robot according to claim 1, characterized in that: A protective cover (12) is installed on the housing (1) on the housing body (11). The housing body (11) forms a flange protruding outward at the upper end. The flange includes a longitudinal shaft hole (16) and fastening holes (18). The support wheel (14) is installed using the shaft hole (16), and fasteners are passed through the fastening holes (18) to achieve the firm installation of the protective cover (12) on the housing body (11). The protective cover (12) includes through holes at the transverse positions corresponding to the fastening holes (18) of the housing body (11). By passing fasteners through these holes, the firm installation of the protective cover (12) on the housing body (11) is achieved.

4. The force control universal floating grinding device for a robot according to claim 3, characterized in that: The protective cover (12) includes a longitudinally penetrating middle hole in the middle. The sleeve (3) passes through this middle hole to avoid interference. The middle hole of the protective cover (12) is circular, coaxial and parallel to the adjusting wheel (13). The protective cover (12) includes an annular groove (121) on the lower surface at the edge of its middle hole. By using this annular groove (121), dynamic sealing relative to the adjusting wheel (13) is achieved. The protective cover (12) includes a shaft hole at the transverse position corresponding to the shaft hole (16) of the housing body (11). The support wheel (14) is installed using this shaft hole, enabling the support wheel (14) to be supported and rotate relative to it.

5. A force control universal floating grinding device for a robot according to claim 1, characterized in that: There are at least three support wheels (14) to define the transverse position of the adjusting wheel (13), with one of them being the driving wheel. The support wheel (14) acting as the driving wheel is connected to the control motor (5) to obtain a driving torque, driving and adjusting the rotation angle of the adjusting wheel (13) to adjust and define the transverse position of the upper part of the sleeve (3).

6. The force control universal floating grinding device for a robot according to claim 4, characterized in that: The adjusting wheel (13) is a disc-shaped gear, and an annular sealing ring (131) is fixedly installed on the outer part of the upper surface. The sealing ring (131) has an annular structure, is coaxial with the adjusting wheel (13), is elastic, and snaps into the annular groove (121) of the protective cover (12), enabling the adjusting wheel (13) to abut against the protective cover (12) through the sealing ring (131) to achieve dynamic sealing and prevent chips and dust from entering.

7. A force-controlled universal floating grinding device for a robot according to claim 1, characterized in that: The rubber spring (2) has a non-circular cross-section. The lower part of the outer surface of the rubber spring (2) cooperates with the necking (17) at the lower end of the housing body (11), enabling the rubber spring (2) to pass through the necking (17) and freely expand and contract, defining the transverse position of the rubber spring (2) and the sleeve (3) at the lower part and preventing the rubber spring (2) from rotating relative to the housing body (11).

8. A force-controlled universal floating grinding device for a robot according to claim 1, characterized in that: The sleeve (3) forms a flange at the upper end; The flange of the sleeve (3) includes a longitudinal through-hole, and a fastener passes through the through-hole to be fixedly connected to the grinding motor (4), so that the grinding motor (4) is installed at the upper end of the sleeve (3); The sleeve (3) fixedly installs a rubber ring (31) on the lower surface of its flange, and contacts the upper surface of the adjusting wheel (13) through the rubber ring (31); The rubber ring (31) is of an annular structure and has elasticity, capable of generating a buffering effect.

9. A force-controlled universal floating grinding device for a robot according to claim 1, characterized in that: It includes a sheath (8); The lower part of the housing (11) is inwardly recessed and includes a surrounding groove (15) on the lower part of the outer surface; The sheath (8) is of a longitudinal conical tube structure, includes a circular upper opening at the upper end, and includes a circular lower opening at the lower end; The sheath (8) penetrates into the housing (11) of the outer shell (1) through its upper opening; The upper end of the sheath (8) is snapped into the groove (15) of the housing (11), so that the sheath (8) is installed at the upper end of the housing (11) of the outer shell (1); The lower end of the sheath (8) is inwardly recessed, and the inner lower edge of the end cover (6) passes out of its lower opening; The outer surface of the sheath (8) is corrugated and can elastically expand and contract longitudinally, so that the sheath (8) tightly adheres to the lower surface of the end cover (6) upward at the lower end, preventing chips and dust from invading and having a protective effect.

10. An intelligent universal floating control method for a robot equipped with the grinding device according to any one of claims 1-9, for performing universal floating force-controlled grinding, characterized in that: Establish and store the following operation models: First, number the workpiece blank model, denoted as m ; Denote the position coordinates of the reference point of the grinding head as ([[]] x, y, z ); Denote the rotation angle of the control motor (5) as θ ; The grinding device installs a force sensor by using the mounting cylinder (19) of the housing (1), and then installs it on the manipulator of the robot through the force sensor; the cutting force obtained by the force sensor is denoted as f ; Record and store θ ( i , m , x , y , z ) and f ( i, m, x, y, z ) Among them, i is the coordinate serial number; θ ( i, m, x, y, z ) is the rotation angle of the control motor (5) when the reference point of the grinding head reaches the position with the m th coordinate of ( i ) during the rough machining process of the workpiece with the grinding process number x, y, z ; f ( i, m, x, y, z ) is the cutting force value obtained by the force sensor when the reference point of the grinding head reaches the position with the m th coordinate of ( i ) during the rough machining process of the workpiece with the grinding process number x, y, z ; Second, write a machining program for the workpiece blank numbered m , including at least the coordinate sequence { i, m, x, y, z } of the movement of the reference point of the grinding head during machining; Third, conduct a grinding experiment on the workpiece blank numbered m , observe the grinding effect and record f ( i, m, x, y, z ), obtain the maximum and minimum cutting forces, which are respectively denoted as maxf ( m ) and minf ( m ); Fourth, continue with the grinding experiment and adjust θ ( i, m, x, y, z ), replace the rubber spring (2) to reduce( maxf ( m )) – minf ( m )) value and improve the control accuracy; The control method includes the following steps: Step 1: Setup i The initial value is 0; set the variable tempx, tempy and tempz , and let their initial values ​​be { 0, m, x, y, z }middle x, y, and z The value of; adjust the rotation angle of the control motor (5) to 0°; Step 2: The robot starts the grinding operation on the workpiece blank numbered m ; the grinding motor (4) is started; In the third step, the reference point of the grinding head moves, and its coordinates { x, y, z } change; Determine whether the reference point of the grinding head has reached the i th coordinate point; if ( tempx == x and tempy == y and tempz = =z ) is true, then it has reached; otherwise it has not reached; Fourth step, if reached, then: Adjust the rotation angle of the control motor (5) to θ ( i, m, x, y, z ) to ensure the required grinding effect and processing efficiency; i = i + 1 ； Set the values of variables tempx , tempy and tempz to the values in { i, m, x, y, z }; x, y, and z respectively. Go to the third step}; Fifth step, judge whether the processing is finished; if not, go to the third step; The grinding motor (4) stops; End.

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