3t force-controlled end effector

Abstract

The application provides a 3T force control end effector, which comprises a fixed platform, three motion branches and a movable platform; wherein the three motion branches are arranged on the fixed platform along X, Y and Z directions respectively, and the three motion branches are arranged in parallel between the fixed platform and the movable platform. The three motion branches are arranged in parallel between the fixed platform and the movable platform, and three prismatic degrees of freedom are driven by the three motion branches respectively, so that the end effector has high rigidity and good flexibility; the fixed platform, the motion branches and the movable platform form an isotropic mechanism without singularity, which not only solves the problem that the existing end tool with single degree of freedom is difficult to be applied to complex working conditions, but also reduces the design difficulty of the controller, eliminates the singular pose in the motion process, improves the force transmission performance of the end effector, and is beneficial to improving the force control operation precision of the robot.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot automation, in particular to a 3T force control end effector. BACKGROUND

[0002] With the high-quality development of manufacturing industry, the surface quality requirements of workpieces become more stringent. Polishing and grinding as a key post-process of workpiece finishing, how to improve the processing quality becomes a key problem to improve the quality of workpieces. The traditional manual polishing and grinding mode has the shortcomings of low efficiency, high cost and difficult to guarantee the consistency of product quality. The rapid development of industrial robot technology brings a new solution to the polishing and grinding field. Installing a force control end tool at the end of the industrial robot makes the polishing and grinding system have a relatively flexible working space of the industrial robot, and also has the advantages of low inertia, high response speed and high force control precision of the end effector, which has become the mainstream development trend of current robot automation polishing technology.

[0003] At present, the end tool is mainly a single degree of freedom structure. However, the single degree of freedom structure is difficult to apply to complex working condition requirements. For example, when polishing and grinding the side of the inner hole cavity, lateral force control needs to be realized. Such end effector cannot be used. SUMMARY

[0004] In view of this, the present application provides a 3T force control end effector, which aims to solve the problem that the existing end tool is a single degree of freedom structure and is difficult to apply to complex working condition requirements.

[0005] The present application provides a 3T force control end effector, which comprises a fixed platform, three motion branch chains and a moving platform. The fixed platform serves as a support. Three motion branch chains are arranged on the fixed platform along the X, Y and Z directions respectively, and are arranged in parallel between the fixed platform and the moving platform. The three motion branch chains are used to drive the moving platform to move along the X, Y and Z directions respectively, and enable the moving platform to slide relative to the other two motion branch chains under the driving action of any one of the motion branch chains, so as to realize the uncoupled movement of the moving platform in three orthogonal directions, and further drive the end tool to perform force control operation.

[0006] Further, the 3T force-controlled end effector, the motion branch comprises: a driving P joint for applying driving force along a first preset direction; a passive motion PP joint slidably connected with a power output end of the driving P joint along a second preset direction, and the passive motion PP joint is also slidably connected with the moving platform along a third preset direction, for driving the moving platform to move along the first preset direction under the driving action of the driving P joint, and under the driving of the other two motion branches, the passive motion PP joint can move along the second preset direction relative to the power output end of the driving P joint, or the moving platform can move along the third preset direction relative to the passive motion PP joint; wherein the first preset direction, the second preset direction and the third preset direction are mutually perpendicular directions, and the first preset direction is any one of X, Y and Z directions.

[0007] Further, the 3T force-controlled end effector, the driving P joint comprises: a driving shell; a driving cylinder arranged on the driving shell along the first preset direction; a driving voice coil motor arranged on the driving shell in parallel with the driving cylinder; and a driving plate connected with the power output ends of the driving cylinder and the driving voice coil motor, for moving along the first preset direction under the double driving action of the driving cylinder and the driving voice coil motor.

[0008] Further, the 3T force-controlled end effector, the driving voice coil motor comprises: an outer magnetic yoke, a support plate and a wire holder; wherein the support plate is arranged inside the outer magnetic yoke along the first preset direction, and the support plate plays a supporting role; an inner magnetic yoke is arranged at the middle position of the top wall and / or the bottom wall of the support plate, and magnetic steel is further arranged on both sides of the top wall and / or the bottom wall of the support plate at the inner magnetic yoke; the wire holder is slidably sleeved on the outer periphery of the support plate, and a coil is wound on the outer periphery of the wire holder, and there is an air gap between the inner wall of the wire holder and the magnetic steel, for when the coil is connected with current, the Lorentz force makes the wire holder and the coil move along the axial direction of the wire holder to drive the driving plate to move along the first preset direction.

[0009] Further, the 3T force-controlled end effector, both ends of the wire holder are provided with bosses, and each of the bosses is connected with the driving plate through a connecting plate, and the connecting plate is provided with a gas path unit for connecting gas to cool the coil.

[0010] Further, the 3T force-controlled end effector, the driving cylinder is provided with a displacement sensor for detecting the driving displacement of the driving P joint along the direction thereof.

[0011] Further, the 3T force-controlled end effector, the two opposite wall surfaces of the passive motion PP joint are respectively provided with a first guide structure and a second guide structure, which are used for guiding the relative movement between the passive motion PP joint and the driving plate and the relative movement between the passive motion PP joint and the moving platform.

[0012] Further, the 3T force-controlled end effector, the moving platform is provided with a pressure sensor, which is used for acquiring the acting force between the moving platform and the end tool on the moving platform, so as to control the driving voice coil motor of the motion branch chain based on the acting force between the moving platform and the end tool on the moving platform, so that the driving voice coil motor outputs a pushing force or a pulling force, and then controls the contact force between the end tool and the workpiece to be machined.

[0013] Further, the 3T force-controlled end effector, the moving platform includes three mutually perpendicular support plates, which are used for connecting three motion branch chains respectively.

[0014] Further, the 3T force-controlled end effector, the fixed platform includes: a plane support plate used for supporting two motion branch chains; and an L-shaped bending plate, a fixed part of which is arranged on the plane support plate, and a support part of which is arranged perpendicular to the plane support plate, and used for supporting another motion branch chain.

[0015] The 3T force-controlled end effector provided by the application has the advantages that three motion branch chains are arranged in parallel between the fixed platform and the moving platform, three translational degrees of freedom are driven and three-direction motion is realized through the three motion branch chains, that is, the three motion branch chains are used to realize the motion of the moving platform in three translational directions, so that the end effector has high rigidity and good flexibility, the fixed platform, the motion branch chain and the moving platform form a non-singular isotropic mechanism, three-direction control can be realized, the existing end tool structure with single degree of freedom can be applied to complex working conditions, the design difficulty of the controller is reduced, singular poses in the motion process are eliminated, the force transmission performance of the end effector is improved, the force control operation precision of the robot is improved, the force control complexity is simplified, and the like.

[0016] Further, the driving P joint adopts parallel connection of a driving air cylinder and a driving voice coil motor to form a pneumatic and electric hybrid driving force control end effector with low inertia, high thrust density, high force control precision, high response speed, shock absorption and impact resistance, and good flexibility. Since the driving air cylinder has good flexible buffering capacity and can realize linear force output, the driving voice coil motor has the advantages of simple structure, high force linearity, fast response speed and simple control, therefore, parallel output of the two can integrate the above advantages, has high force control precision and fast response, and has certain flexibility and shock absorption performance, improves the force control precision and response speed while suppressing vibration in the polishing process, the driving voice coil motor compensates the output force of the driving air cylinder, therefore, the end effector has a large force control range and high working bandwidth, and can solve the problems of poor flexibility, low thrust density, small force control range of a single motor and slow response and low precision of a single air cylinder.

[0017] In particular, the driving voice coil motor adopts a split permanent magnet, and the driving voice coil motor is magnetically conductive through a magnetic yoke. The driving voice coil motor has compact structure, small overall weight, high thrust density and high output linearity, that is, the current given and the force output are in linear relationship, ensures stable power output, and facilitates control of the output force. BRIEF DESCRIPTION OF DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the application. Moreover, the same reference numerals are used throughout the same figures. In the drawings:

[0019] Figure 1 A structural schematic diagram of a 3T force control end effector provided for an embodiment of the application;

[0020] Figure 2 A top view of a 3T force control end effector provided for an embodiment of the application;

[0021] Figure 3 A structural schematic diagram of a 3T force control end effector provided for an embodiment of the application;

[0022] Figure 4 A structural schematic diagram of a motion branch provided for an embodiment of the application;

[0023] Figure 5 A front view of a motion branch provided for an embodiment of the application;

[0024] Figure 6 A structural schematic diagram of a driving voice coil motor provided for an embodiment of the application;

[0025] Figure 7 A front view of a driving voice coil motor provided for an embodiment of the application;

[0026] Figure 8 A schematic diagram of driving a voice coil motor is provided for the embodiment of the present application;

[0027] Figure 9 Another schematic diagram of driving a voice coil motor is provided for the embodiment of the present application;

[0028] Figure 10 A structural schematic diagram of a wire frame is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0029] Exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and the scope of the present disclosure can be accurately conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0030] Referring to Figures 1-2 which shows a preferred structure of a 3T force-controlled end effector provided by the embodiment of the present application. As shown in the figure, the end effector comprises a fixed platform 1, three motion branches 2 and a moving platform 3; wherein,

[0031] The fixed platform 1 serves as a support. Specifically, the fixed platform 1 can be connected at the end of a robot hand (not shown in the figure) to make preliminary position adjustment at the end of the robot hand, thereby driving the end tool 4 provided on the moving platform 3 to make preliminary position adjustment. The end tool 4 can be a polishing tool, or other tools, which is not limited in the present embodiment.

[0032] Three movement branches 2 are arranged on the fixed platform 1 along the X, Y and Z directions respectively, and the three movement branches 2 are arranged in parallel between the fixed platform 1 and the movable platform 3, for driving the movable platform 3 to move along the X, Y and Z directions respectively, and enabling the movable platform 3 to slide relative to the other two movement branches 2 under the driving action of any one movement branch 2, so as to realize the uncoupled movement of the movable platform 3 in three orthogonal directions, and further drive the end tool 4 to perform force control operation. Specifically, the movable platform 3 is used for supporting the end tool 4 to drive the end tool 4 to adjust the position and adjust and control the force. The three movement branches 2 can be an X movement branch 201, a Y movement branch 202 and a Z movement branch 203 respectively, the X movement branch 201, the Y movement branch 202 and the Z movement branch 203 are arranged on the fixed platform 1 along the X, Y and Z directions respectively, and the power output ends of the X movement branch 201, the Y movement branch 202 and the Z movement branch 203 can reciprocate linearly along the X, Y and Z directions respectively. The movable platform 3 is connected with the power output ends of the X movement branch 201, the Y movement branch 202 and the Z movement branch 203 respectively, for moving along the X, Y and Z directions under the driving action of the X movement branch 201, the Y movement branch 202 and the Z movement branch 203, and the movable platform 3 can slide relative to the other two movement branches 2 under the driving action of any one movement branch 2, for example, when the X movement branch 201 drives, that is, the power output end of the X movement branch 201 drives the movable platform 3 to reciprocate linearly along the X direction, the movable platform 3 synchronously reciprocates linearly along the X direction with the power output end of the X movement branch 201, and in this process, the movable platform 3 also slides relative to the Y movement branch 202 and the Z movement branch 203, that is, the Y movement branch 202 and the Z movement branch 203 are stationary, and the movable platform 3 also reciprocates linearly along the X direction relative to the power output ends of the Y movement branch 202 and the Z movement branch 203, so as to realize the uncoupled movement of the movable platform 3 in three orthogonal directions, and improve the force transmission and flexibility of the structure. Among them, the three orthogonal directions are the X, Y and Z directions.

[0033] In the embodiment, the three movement branches 2 each have three translational degrees of freedom, can realize driving of the corresponding translational degrees of freedom, can realize that the movable platform 3 has three translational degrees of freedom, has high flexibility, and has more widely application scenarios, and can be applicable to end face, inner hole and cavity surface polishing and grinding.

[0034] It can be known that, in the embodiment, the three movement branches 2 are arranged in parallel between the fixed platform 1 and the movable platform 3, the three movement branches 2 drive the three translational degrees of freedom respectively and realize three-direction movement, such as Figure 3As shown, three motion branch chains 2 are adopted to realize the movement of the moving platform 3 in three translational directions, so that the end effector has high rigidity and good flexibility. The fixed platform 1, the moving platform 3 and the motion branch chain 2 form a non-singular isotropic mechanism. The existing end tool with single degree of freedom can be applied to complex working conditions. Meanwhile, the design difficulty of the controller is reduced, the singular pose in the movement process is eliminated, the rigidity and force transmission performance of the end effector are improved, the force control complexity is simplified, and the force control operation precision of the robot is improved.

[0035] In the embodiment, a pressure sensor (not shown in the figure) can be arranged on the moving platform 3 to obtain the acting force between the moving platform 3 and the end tool 4 on the moving platform 3. The voice coil motor 214 of the motion branch chain 2 is controlled based on the acting force between the moving platform 3 and the end tool 4 on the moving platform 3, so that the voice coil motor 214 outputs a pushing force or a pulling force, and the contact force between the end tool 4 and the workpiece to be machined is controlled. Specifically, the pressure sensor can be connected with a controller. The controller is used to receive the acting force between the moving platform 3 and the end tool 4 on the moving platform 3, and control the three motion branch chains 2 based on the acting force between the moving platform 3 and the end tool 4 on the moving platform 3, so as to control the movement output of the three directions of the three motion branch chains 2, and realize the movement control of the moving platform 3, so that the end tool 4 outputs with a preset output force. The preset output force can be determined based on the actual situation, which is not limited in the embodiment.

[0036] Continuing to refer to Figure 1 The fixed platform 1 includes a plane support plate 11 and an L-shaped bent plate 12. The plane support plate 11 is used to support two motion branch chains 2. The fixed part 121 of the L-shaped bent plate 12 is arranged on the plane support plate 11, and the support part 121 thereof is arranged perpendicular to the plane support plate 11, and is used to support the other motion branch chain 2.

[0037] Specifically, the plane support plate 11 is a flat plate structure, and a gap is arranged at the plane support plate 11. The L-shaped bent plate 12 is arranged at the gap, and the fixed part 121 of the L-shaped bent plate 12 is arranged flat and fixed on the plane support plate 11 by bolts. Of course, the two can also be connected by bolt connection and the like, and the connection mode is not limited in the embodiment. The support part 121 of the L-shaped bent plate 12 is arranged perpendicular to the plane support plate 11, that is, the support part 121 is arranged perpendicular to the plane support plate 11. The fixed seat of the X motion branch chain 201 and the Y motion branch chain 202 can be fixed on the plane support plate 11, and the fixed seat of the Z motion branch chain 203 can be fixed on the fixed part 121. The fixed mode can adopt bolt connection, or other fixed mode connection, which is not limited in the embodiment.

[0038] Referring to Figures 4-5 , it shows the preferred structure of the motion branch provided by the embodiment of the application. As shown in the figure, the motion branch 2 comprises: a driving P joint 21 and a passive motion PP joint 22; wherein the driving P joint 21 is used to apply a driving force along a first preset direction to the passive motion PP joint 22, so as to drive the passive motion PP joint 22 to move the moving platform 3 along the first preset direction; the passive motion PP joint 22 is connected to the power output end of the driving P joint 21 along a second preset direction in a slidable manner, and the passive motion PP joint 22 is also connected to the moving platform 3 along a third preset direction in a slidable manner, for driving the moving platform 3 to move along the first preset direction under the driving of the driving P joint 21, and under the driving of the other two motion branches 2, the passive motion PP joint 22 can move along the second preset direction relative to the power output end of the driving P joint 21, or the moving platform 3 can move along the third preset direction relative to the passive motion PP joint 22; wherein the first preset direction, the second preset direction and the third preset direction are three mutually perpendicular directions, and the first preset direction is any one of the X, Y and Z directions.

[0039] Specifically, the driving P joint 21 can be arranged on the fixed platform 1 along the first preset direction, and the fixed seat of the driving P joint 21 can be fixed on the fixed platform 1 by bolts or other fixing means, and the power output end of the driving P joint 21 can move reciprocatingly along the direction along which it is arranged, i.e. the first preset direction, so as to realize the driving of the movement in the first preset direction, and also to apply a driving force along the first preset direction, so that the passive motion PP joint 22 moves accordingly and realizes the control of the acting force of the moving platform 3 in the first preset direction. The passive motion PP joint 22 can be arranged on the power output end of the driving P joint 21, and a first guide structure 23 can be arranged between the first wall surface (such as the left wall surface as shown in the figure) of the passive motion PP joint 22 and the power output end of the driving P joint 21, for guiding the relative linear motion of the passive motion PP joint 22 relative to the power output end of the driving P joint 21 along the second preset direction, so that the passive motion PP joint 22 can reciprocate linearly along the second preset direction relative to the power output end of the driving P joint 21 of the other motion branch 2 under the driving of the driving P joint 21 of the motion branch 2, synchronously with the moving platform 3. Further preferably, a second guide structure 24 can be arranged between the second wall surface (such as the right wall surface as shown in the figure) of the passive motion PP joint 22 and the moving platform 3, for guiding the relative linear motion of the passive motion PP joint 22 relative to the moving platform 3 along the third preset direction, so that the moving platform 3 can reciprocate linearly along the third preset direction relative to the passive motion PP joint 22 under the driving of the passive motion PP joint 22 of the motion branch 2, synchronously with the passive motion PP joint 22. Figure 5 Figure 5 ​The second guide structure 24 can be arranged on the left side wall surface shown) for guiding the relative linear motion of the movable platform 3 along the third preset direction relative to the passive motion PP joint 22, so that the movable platform 3 can reciprocate linearly along the third preset direction relative to the power output end of the driving P joint 21 of the motion branch 2 and the passive motion PP joint 22 under the driving of the driving P joint 21 of the motion branch 2. In the embodiment, the first guide structure 23 and the second guide structure 24 are arranged on the two opposite wall surfaces of the passive motion PP joint 22, and can be guided by the motion of the passive motion PP joint 22 relative to the power output end of the driving P joint 21 and the motion of the movable platform 3 relative to the passive motion PP joint 22. The first guide structure 23 and the second guide structure 24 are both two groups to ensure the stability of the motion. That is, the movable platform 3 has three translational degrees of freedom, one degree of freedom of the current motion branch 2 is driven by the driving P joint 21 of the motion branch 2, and the other two degrees of freedom are driven by the other two motion branches 2. The degrees of freedom of each motion branch 2 are guided by the first guide structure 23 and the second guide structure 24 to ensure that the end effector has high flexibility, reduce the complexity of control design, and improve the force transmission performance between the branches.

[0040] In the embodiment, when the motion branch 2 is the X motion branch 201, the first preset direction is the X direction, the second preset direction can be the Y direction, and the third preset direction is the Z direction. Of course, the second preset direction can also be the Z direction, and the third preset direction can also be the Y direction, which is not limited in the embodiment. When the motion branch 2 is the Y motion branch 202, the first preset direction is the Y direction, the second preset direction can be the X direction, and the third preset direction is the Z direction. Of course, the second preset direction can also be the Z direction, and the third preset direction can also be the X direction, which is not limited in the embodiment. When the motion branch 2 is the Z motion branch 203, the first preset direction is the Z direction, the second preset direction can be the X direction, and the third preset direction is the Y direction. Of course, the second preset direction can also be the Y direction, and the third preset direction can also be the X direction, which is not limited in the embodiment.

[0041] Continuing to refer to Figures 4-5 , the driving P joint 21 comprises a driving shell 211, a driving cylinder 212, a driving voice coil motor 213 and a driving plate 214. The driving cylinder 212 is arranged on the driving shell 211 along the first preset direction. The driving voice coil motor 213 is arranged on the driving shell 211 in parallel with the driving cylinder 212. The driving plate 214 is connected with the power output ends of the driving cylinder 212 and the driving voice coil motor 213 respectively, and is used to move along the first preset direction under the double driving of the driving cylinder 212 and the driving voice coil motor 213.

[0042] Specifically, the driving shell 211 can be a support seat, as a fixed seat of the kinematic chain 2, which can be fixedly connected to the fixed platform 1 by bolts or the like. The driving shell 211 is a U-shaped shell structure, as shown in Figure 5 The driving shell 211 is a U-shaped shell structure, as shown in Figure 5 The driving shell 211 is a U-shaped shell structure, as shown in

[0043] It can be seen that the driving P joint 21 adopts parallel connection of the driving cylinder 212 and the driving voice coil motor 213, forming a kind of pneumatic and electric hybrid driving force control end effector with low inertia, high force control precision, high response speed, shock absorption, impact resistance and good flexibility. Since the driving cylinder 212 has good flexible buffering capability and can realize linear force output, the driving voice coil motor 213 has the advantages of simple structure, high force linearity, fast response speed and easy control, therefore, parallel output of the two can integrate the above advantages, not only has the characteristics of high force control precision and fast response, but also has certain flexibility and shock absorption performance, improves the force control precision and response speed while suppressing vibration in the polishing process, the driving voice coil motor 213 compensates the output force of the driving cylinder 212, therefore, the end effector has a large force control range and a high working bandwidth, which can solve the problems of low thrust density, poor driving flexibility of a single motor and slow response and low precision of a single cylinder drive.

[0044] In the embodiment, the displacement sensor 215 can be arranged on the driving cylinder 212 to detect the driving stroke of the driving P joint 21 along the direction in which the driving P joint 21 is located, so as to perform driving closed-loop control based on the driving stroke. Specifically, the displacement sensor 215 is also connected to the controller, and the driving cylinder 212 can be controlled in a closed loop by reading the driving stroke of the driving cylinder 212 along the direction in which the driving cylinder 212 is located based on the controller. In addition, the controller also reads the acting force between the moving platform 3 and the end tool 4 on the moving platform 3 based on the pressure sensor to control the driving voice coil motor 213, that is, the controller mainly controls the output force of the cylinder, controls the current size and direction of the driving voice coil motor 213, so that the driving voice coil motor 213 can output both outward thrust and inward pull, so that the actual contact force quickly approaches the preset contact force, and the output contact force control is realized. That is, the output of the active joint is adjusted through the feedback signals of the pressure sensor and the displacement sensor to realize the expected force output.

[0045] Referring to Figures 6-9 , a preferred structure of the driving voice coil motor provided by the embodiment of the application is shown. As shown in the figure, the driving voice coil motor 213 comprises: an outer magnetic yoke 2131, a support plate 2132, an inner magnetic yoke 2133, a magnetic steel 2134, and a bobbin 2135; wherein the support plate 2132 is arranged inside the outer magnetic yoke 2131 along a first preset direction, and the support plate 2132 plays a supporting role; the inner magnetic yoke 2133 is arranged at the middle position (relative to the position shown in the figure) of the top wall and / or the bottom wall of the support plate 2132, and the magnetic steel 2134 is further arranged on both sides of the inner magnetic yoke 2133 of the top wall and / or the bottom wall of the support plate 2132; the bobbin 2135 is slidably sleeved on the outer periphery of the support plate 2132, and the outer periphery of the bobbin 2135 is wound with a coil 2136, and the inner wall of the bobbin 2135 and the magnetic steel 2134 have an air gap therebetween; when the coil 2136 is passed through a current, the Lorentz force makes the bobbin 2135 and the coil 2136 move along the axial direction (such as the direction perpendicular to the paper surface shown in the figure) of the bobbin 2135, so as to drive the driving plate 214 to move along the first preset direction. Figure 8 Figure 8

[0046] Specifically, in order to improve the symmetry of the structure and further realize the balance of the motor output, preferably, the support plate 2132 is arranged at the center position of the outer magnetic yoke 2131, the magnetic steel 2134 is a plurality of and symmetrically arranged on the upper and lower two wall surfaces of the support plate 2132, and the inner magnetic yoke 2133 is installed between the magnetic steels 2134 to form a closed circuit. The outer magnetic yoke 2131 can be a shell structure arranged with openings on both sides, and the openings on both sides facilitate the protrusion of the bobbin 2135 to connect the driving plate 214 and realize the driving of the driving plate 214. The outer magnetic yoke 2131 is arranged along the first preset direction (such as the direction perpendicular to the paper surface shown in the figure), and the inner magnetic yoke 2133 is arranged along the second preset direction (such as the direction parallel to the paper surface shown in the figure). Figure 7 ​​The outer magnetic yoke 2131 is provided with a clamping groove 21311 on the inner wall of the two vertically arranged support plates, which is used for clamping the two ends of the support plate 2132, so that the support plate 2132 is clamped at the middle position of the outer magnetic yoke 2131. The support plate 2132 is provided with a limiting protruding structure for positioning the inner magnetic yoke 2133 and the magnetic steel 2134. The limiting protruding structure can divide the top wall and the bottom wall of the support plate 2132 into eight accommodation parts for respectively mounting eight magnetic steels 2134. The inner magnetic yoke 2133 can be four, two by two, and the two groups of inner magnetic yokes 2133 are respectively arranged at the middle positions of the top wall and the bottom wall of the support plate 2132. The two inner magnetic yokes 2133 in each group are arranged in parallel along the same line on the support plate 2132 in the width direction (perpendicular to the paper surface direction) of the support plate 2132. Figure 8 The magnetic steel 2134 can be eight, which is arranged in the eight accommodation parts divided by the limiting protruding structure, and the magnetic steel 2134 can be attached to the support plate 2131. The outer magnetic yoke 2131, the inner magnetic yoke 2133 form a closed magnetic circuit, and a uniformly distributed radial magnetic field is formed in the inside of the driving voice coil motor 213. The outer magnetic yoke 2131, the support plate 2132, the inner magnetic yoke 2133, and the magnetic steel 2134 form the stator part of the driving voice coil motor 213. The rotor part of the driving voice coil motor 213 includes the bobbin 2135 and the coil 2136 wound on the bobbin 2135. The cross section of the bobbin 2135 is a ring joint, and the coil 2136 can be uniformly wound on the bobbin by a winding machine. The bobbin and the coil together constitute the rotor of the driving voice coil motor 213. The bobbin 2135 can be sleeved around the magnetic steel 2134 with a predetermined air gap by using a gasket. When a certain current is input into the coil 2136, the Lorentz force makes the rotor of the driving voice coil motor 213 produce axial movement. Among them, Figure 8 The arrowed line represents the coil magnetic force line, Figure 9 The arrowed line represents the magnetic steel magnetic force line.

[0047] In this embodiment, the magnetic steel 2134 can be a neodymium iron boron permanent magnet, the bobbin 2135 and the support plate 2132 are ordinary aluminum alloy materials, and the coil 2136 is selected from enameled copper wire.

[0048] It can be seen that the driving voice coil motor 213 adopts a split type permanent magnet, and the magnetic yoke is used for magnetic conduction. The driving voice coil motor 213 has compact structure, small overall weight, high thrust density and high output linearity, that is, the current given and the force output are in linear relationship, which ensures the stability of power output and facilitates the control of output force.

[0049] Continuing to refer to Figure 6 and Figure 10 , the two ends (such as the left and right ends shown in Figure 10 ) of the bobbin 2135 are provided with bosses 21351 for realizing power output.Figure 4 As shown, each boss 21351 is connected with the driving plate 214 through the connecting plate 2137, and the connecting plate 2137 is provided with a gas path unit (not shown in the figure), which can form a hollow closed gas path for passing in gas to dissipate heat for the coil 2136. Specifically, the mounting bosses 21351 are designed on the front end face and the side face of the yoke 2135, and the bolts are threadedly connected with the bosses 21351 through the mounting plate 2137, so as to realize the force output of the driving voice coil motor 213 and improve the stability of the force output of the driving voice coil motor 213 and the flexibility of the later application.

[0050] In summary, the 3T force-controlled end effector provided in the embodiment is based on a parallel mechanism configuration, and three movement branches 2 are arranged in parallel between the fixed platform 1 and the moving platform 3, and three translational degrees of freedom are realized through the three movement branches 2, as shown in the figure. Figure 3 That is, the three movement branches 2 are used to realize the movement of the moving platform 3 in three translational directions, so that the end effector has high rigidity and good flexibility. The movement branches 2 form a non-singular isotropic mechanism, which not only solves the problem that the existing end tool with single degree of freedom is difficult to be applied to complex working conditions, but also reduces the design difficulty of the controller, eliminates the singular pose in the movement process, improves the rigidity and force transmission performance of the end effector, and simplifies the force control complexity.

[0051] Further, the driving P joint 21 adopts parallel connection of the driving cylinder 212 and the driving voice coil motor 213 to form a gas-electric hybrid driving force-controlled end effector with low inertia, high thrust density, high force control accuracy, high response speed, shock absorption and impact resistance, and good flexibility. Since the driving cylinder 212 has good flexible buffering capacity and can realize linear force output, the driving voice coil motor 213 has the advantages of simple structure, high force linearity, fast response speed and simple control, therefore, the parallel output of the two can integrate the above advantages, has the characteristics of high force control accuracy and fast response, and has certain flexibility and shock absorption performance, improves the force control accuracy and response speed while suppressing vibration in the polishing process. The driving voice coil motor 213 compensates the output force of the driving cylinder 212, so that the end effector has a large force control range and a high working bandwidth, and can solve the problems of poor flexibility, low thrust density, small force control range of a single motor drive, and slow response and low accuracy of a single cylinder drive.

[0052] Especially, the driving voice coil motor 213 adopts a split type permanent magnet which is magnetically guided through a magnetic yoke. The driving voice coil motor 213 has compact structure, small overall weight, high thrust density and high output linearity, that is, the current given and the force output are in linear relationship, which ensures the stability of power output and is convenient for controlling the output force.

[0053] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0054] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A 3T force-controlled end effector, characterized in that, include: Fixed platform, three motion chains, and moving platform; among them, The fixed platform serves a supporting function; The three kinematic branches are respectively arranged along the X, Y, and Z directions on the fixed platform, and are connected in parallel between the fixed platform and the moving platform. They are used to drive the moving platform to move along the X, Y, and Z directions, and enable the moving platform to slide relative to the other two kinematic branches under the driving action of any one of the kinematic branches, so as to realize the uncoupled movement of the moving platform in three orthogonal directions, thereby driving the end tool to perform force control operation. The kinematic branch includes: Drive joint P to apply a driving force in a first preset direction; A passive motion PP joint is slidably connected to the power output end of the driving P joint along a second preset direction, and also slidably connected to the moving platform along a third preset direction. This passive motion PP joint, under the driving action of the driving P joint, drives the moving platform to move along a first preset direction. Furthermore, when the other two motion chains are driven, the passive motion PP joint can move relative to the power output end of the driving P joint along the second preset direction, or the moving platform can move relative to the passive motion PP joint along the third preset direction. The first, second, and third preset directions are three mutually perpendicular directions, and the first preset direction is any one of the X, Y, and Z directions.

2. The 3T force-controlled end effector according to claim 1, characterized in that, The drive P joint includes: Drive housing; A drive cylinder is disposed on the drive housing along the first preset direction; A voice coil motor is connected in parallel with the drive cylinder and mounted on the drive housing. A drive plate, which is connected to the power output terminals of the drive cylinder and the drive voice coil motor respectively, is used to move along the first preset direction under the dual drive action of the drive cylinder and the drive voice coil motor.

3. The 3T force-controlled end effector according to claim 2, characterized in that, The driving voice coil motor includes: an outer magnetic yoke, a support plate, and a wire frame; wherein... The support plate is disposed inside the outer magnetic yoke along the first preset direction, and the support plate serves a supporting function. An inner magnetic yoke is provided at the middle position of the top wall and / or bottom wall of the support plate, and magnets are also provided on both sides of the inner magnetic yoke on the top wall and / or bottom wall of the support plate. The wire frame is slidably sleeved on the outer periphery of the support plate, and a coil is wound around the outer periphery of the wire frame. There is an air gap between the inner wall of the wire frame and the magnet, so that when current is passed through the coil, the Lorentz force causes the wire frame and the coil to move along the axial direction of the wire frame, thereby driving the drive plate to move along the first preset direction.

4. The 3T force-controlled end effector according to claim 3, characterized in that, Both ends of the coil frame are provided with bosses, and each boss is connected to the drive plate through a connecting plate. Furthermore, the connecting plate is provided with an air passage unit for introducing gas to dissipate heat from the coil.

5. The 3T force-controlled end effector according to claim 2, characterized in that, The drive cylinder is equipped with a displacement sensor for detecting the drive displacement of the drive P joint along its direction.

6. The 3T force-controlled end effector according to claim 2, characterized in that, The passive motion PP joint has two opposing walls respectively provided with a first guide structure and a second guide structure, which are used to guide the relative movement between the passive motion PP joint and the drive plate, and the relative movement between the passive motion PP joint and the moving platform.

7. The 3T force-controlled end effector according to any one of claims 1 to 6, characterized in that, The moving platform is equipped with a pressure sensor to obtain the force between the moving platform and the end tool on the moving platform. Based on the force between the moving platform and the end tool on the moving platform, the voice coil motor driving the motion chain is controlled so that the voice coil motor outputs a thrust outward or a pull inward, thereby controlling the contact force between the end tool and the workpiece.

8. The 3T force-controlled end effector according to any one of claims 1 to 6, characterized in that, The moving platform includes three support plates arranged perpendicularly to each other, which are used to connect the three motion chains respectively.

9. The 3T force-controlled end effector according to any one of claims 1 to 6, characterized in that, The fixed platform includes: A planar support plate is used to support two of the motion chains; The L-shaped bending plate has its fixing part set on the flat support plate, and its supporting part arranged perpendicular to the flat support plate to support another moving chain.

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