Three-dimensional ball rod instrument for measuring tail end error

Abstract

The invention relates to a three-dimensional ball arm instrument for measuring tail end errors. The three-dimensional ball arm instrument is composed of a tool cup, a ball arm instrument body and a ball arm instrument base. The tool cup mounting seat is connected with an execution tail end of a robot or a main shaft of a machine tool, the tool cup is connected with the ball rod instrument body through magnetic attraction, and the ball rod instrument body is connected with the ball rod instrument base through magnetic attraction; the club body has a measuring function in the club length direction, and the club base has measuring functions in the X direction, the Y direction and the Z direction. Compared with the prior art, the three-dimensional ball bar instrument provided by the invention has two measurement modes, is low in cost, convenient to transport, high in precision, strong in operability and high in practical value, and has a function of measuring the tail end error of the robot.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a three-dimensional ballbar for measuring end error. Background Art

[0002] With the continuous development of science and technology, robot arms are widely used in various industries such as textiles, home appliances, and papermaking. At the same time, the intelligent manufacturing field has higher and higher requirements for the positioning accuracy of robots. The accuracy of robots includes repeatable positioning accuracy and absolute positioning accuracy. At present, the repeatable positioning accuracy of robots can reach 0.05mm, while the absolute positioning accuracy of the robot end is mostly 2-3mm, which is difficult to meet the rigid requirements of intelligent manufacturing. Therefore, it is particularly important to improve the absolute positioning accuracy of robots. Among them, the geometric parameter error is the main factor affecting the absolute positioning accuracy of the robot, accounting for about 90% of the total error. Therefore, the parameters of the robot model can be accurately identified by calibration methods, but parameter calibration requires measuring the end error of the robot.

[0003] The existing method of detecting the end error of the robot is mostly to use a laser tracker, but the price of the laser tracker is very expensive. Secondly, the equipment is heavy, generally 40-50kg, and it will consume a lot of manpower costs in use and transportation.

[0004] Among the various existing measuring devices, the ballbar has the advantages of low price, convenient installation, high detection efficiency, etc. compared with other detection devices. Chinese patent CN111638681A provides an inductive wireless ballbar, which is mainly composed of a ballbar host, a center support assembly, a center cup assembly and a setting ball assembly. The ballbar host includes an inductive probe assembly, a battery assembly, a circuit board assembly and a ballbar body. The wireless measurement system includes a ballbar host, a center support and a center cup assembly, which is used to comprehensively detect the accuracy of the motion axis of a CNC machine tool. The invention is simple to operate, has high accuracy and low cost, but the invention can only measure the distance error between the two ball centers, and cannot measure the spatial position of the robot end.

[0005] In view of this, it is urgent to develop a new type of three-dimensional ballbar that can be used to simply measure the end error of the robot. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a three-dimensional ballbar for measuring end error, so as to improve the accuracy of the end error measurement of the robot.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A three-dimensional ballbar for measuring end-point errors, the three-dimensional ballbar consisting of a tool cup, a ballbar body and a ballbar base;

[0009] The tool cup includes a ball positioning seat, a tool cup mounting seat, and a tool cup magnet;

[0010] The ballbar body comprises: a tool cup connecting ball and a ballbar base connecting ball respectively arranged at two ends of the ballbar body, a ballbar body shell, a ballbar body measuring mechanism, a ballbar body data receiving mechanism, and a ballbar body upper shell;

[0011] The tool cup mounting seat is connected to the end effector of the robot or the spindle of the machine tool, the tool cup is magnetically connected to the ballbar body via the tool cup connecting ball, and the ballbar body is magnetically connected to the ballbar base via the ballbar base connecting ball;

[0012] The ballbar body has a measurement function along the length of the bar, and the ballbar base has measurement functions in three directions: X, Y and Z.

[0013] Furthermore, the ball positioning seat is used to match and connect with the spherical surface of the tool cup connecting ball, the tool cup mounting seat is used to connect with the execution end of the robot or the spindle of the machine tool, and the tool cup magnet is used to magnetically fix the tool cup on the ballbar body.

[0014] Furthermore, the ballbar body measuring mechanism is fixedly connected to the tool cup connecting ball via a tool cup ball mounting seat, and the tool cup connecting ball is threadedly connected to the tool cup ball mounting seat;

[0015] The ballbar body measuring mechanism includes a ballbar body magnetic core, a ballbar body coil, a ballbar body leaf spring A fixing, a ballbar body leaf spring A, a ballbar body leaf spring frame, a ballbar body leaf spring support, a fixing pin, a ballbar body leaf spring B, a ballbar body leaf spring B fixing, a damping cavity, and a self-locking screw.

[0016] Furthermore, the ballbar body magnetic core is threadedly connected to the tool cup ball mounting seat, the ballbar body coil is arranged around the ballbar body magnetic core, the ballbar body coil is electrically connected to the ballbar body data receiving mechanism, and when the ballbar body magnetic core moves, the ballbar body coil can conduct the generated electrical signal to the ballbar body data receiving mechanism;

[0017] The ballbar body leaf spring frame is arranged in a ring shape with the ballbar body leaf spring support as the center, the top of the ballbar body leaf spring support is glued to the tool cup ball mounting seat, the bottom of the ballbar body leaf spring support is glued to the damping cavity, the inner circles of the ballbar body leaf spring A and the ballbar body leaf spring B are sleeved on the ballbar body leaf spring support, the outer circle of the ballbar body leaf spring A is arranged between the ballbar body leaf spring A fixed and the ballbar body leaf spring frame, the ballbar body leaf spring A is fixed to the ballbar body leaf spring frame by screws, the outer circle of the ballbar body leaf spring B is arranged between the ballbar body leaf spring B fixed and the ballbar body leaf spring frame, and the ballbar body leaf spring B is fixed to the ballbar body leaf spring frame by screws;

[0018] The fixing pin passes through the leaf spring support of the ballbar body, and both ends of the fixing pin are fixedly connected to the leaf spring frame of the ballbar body, so as to limit the movement direction to the length direction of the ballbar body;

[0019] The flat ends of the self-locking screw are fixed to the two ends of the bottom where the leaf spring B of the ballbar body is fixed, and the tip of the self-locking screw can be inserted into the damping cavity to achieve the locking of the ballbar body. Further, the ballbar base includes an upper shell of the ballbar base, a ballbar base shell, a lower shell of the ballbar base, a first parallel leaf spring mechanism, a second parallel leaf spring mechanism, a third parallel leaf spring mechanism, a gravity balance mechanism, a tightening mechanism, and a ballbar base data receiving mechanism;

[0020] The limited movement direction of the first parallel leaf spring mechanism is defined as the X direction, the limited movement direction of the second parallel leaf spring mechanism is the Y direction, and the limited movement direction of the third parallel leaf spring mechanism is the Z direction;

[0021] The first parallel leaf spring mechanism comprises an XY leaf spring fixing seat, an X-direction leaf spring A, an X-direction leaf spring B, an X-direction coil of a ballbar base, and an X-direction magnetic core of a ballbar base;

[0022] The second parallel leaf spring mechanism comprises an XY leaf spring fixing seat, a Y-direction leaf spring A, a Y-direction leaf spring B, a Y-direction coil of a ballbar base, and a Y-direction magnetic core of a ballbar base;

[0023] The third parallel leaf spring mechanism includes a Z-spring upper fixing plate, a Z-direction leaf spring A, a Z-spring fixing plate A, a Z-spring fixing plate B, a Z-direction leaf spring B, a ballbar base Z-direction coil, and a ballbar base Z-direction magnetic core;

[0024] The XY leaf spring fixing seat is a cube, the X-direction leaf spring A and the X-direction leaf spring B are respectively fixed on the front and rear surfaces of the XY leaf spring fixing seat, and the Y-direction leaf spring A and the Y-direction leaf spring B are respectively fixed on the left and right surfaces of the XY leaf spring fixing seat;

[0025] The upper fixing plate of the Z spring is connected to the bottom of the XY leaf spring fixing seat, the Z-direction leaf spring A and the Z-direction leaf spring B are arranged parallel to the upper fixing plate of the Z spring, the Z-direction leaf spring fixing plate A and the Z-direction leaf spring fixing plate B are arranged vertically to the upper fixing plate of the Z spring, and the Z-direction leaf spring fixing plate A and the Z-direction leaf spring fixing plate B are used to support and fix the Z-direction leaf spring A and the Z-direction leaf spring B.

[0026] The X, Y and Z directions of the ballbar base are respectively provided with X, Y and Z direction magnetic cores and coils matched with the magnetic cores. The X and Y direction coils of the ballbar base are arranged inside the XY leaf spring fixing seat, and the X direction coil is perpendicular to the X direction leaf spring A and the X direction leaf spring B. The X direction magnetic core is arranged at the center of the X direction coil, the Y direction coil is perpendicular to the Y direction leaf spring A and the Y direction leaf spring B, the Y direction magnetic core is arranged at the center of the Y direction coil, the Z direction coil is installed on the Z direction spring fixing plate A, and the Z direction coil is perpendicular to the Z direction leaf spring A and the Z direction leaf spring B, and the Z direction magnetic core is arranged at the center of the Z direction coil. The ballbar base coils are all electrically connected to the ballbar base data receiving mechanism. When the ballbar base magnetic core moves, the ballbar base coil can conduct the generated electrical signal to the ballbar base data receiving mechanism.

[0027] Furthermore, the gravity balancing mechanism includes an overall mounting seat, a bearing mounting plate, two gravity balancing springs, a screw nut, a screw, a motor, a bearing A, and a bearing B;

[0028] The upper ends of the two gravity balance springs are inserted into the two round holes on the Z spring fixing plate B, and the motor is fixedly mounted on the overall mounting seat;

[0029] The outer ring of the bearing A is fixedly mounted on the bearing mounting plate, the upper end of the screw rod can be inserted into the inner ring of the bearing A, and the lower end of the screw rod is connected to the output shaft of the motor, and the motor is used to drive the screw rod to rotate;

[0030] The middle hole of the screw nut is connected with the screw thread, and two cylinders for inserting the gravity balance spring are arranged at both ends of the screw nut. The screw nut abuts against the lower end of the gravity balance spring. The rotation of the motor drives the screw to rotate, so that the threads between the screw and the screw nut are matched. When the screw nut moves upward with the screw, it squeezes the gravity balance spring, so that the two ends of the gravity balance spring respectively support the Z spring fixing plate B and the screw nut to balance the overall weight. Since there is gravity at the measurement point of the ballbar base XY, it will affect the measurement result in the Z direction. After balancing the gravity, the measurement result will be more accurate.

[0031] Preferably, it is characterized in that the motor is a brushed DC motor.

[0032] Further, the tightening mechanism includes an air intake valve, a SY114 solenoid valve, a SY114 connecting seat, an air pipe connecting piece, an air pipe joint, a first air cylinder, a second air cylinder, and a cylinder mounting seat;

[0033] The SY114 solenoid valve and the SY114 connecting seat are arranged on the overall mounting seat, the air intake valve and the air pipe connecting piece are fixedly connected to the SY114 connecting seat, an air pipe joint is fixedly installed on the upper end of the air pipe connecting piece, the first cylinder and the second cylinder are arranged at the bottom of the cylinder mounting seat, and the two cylinders are arranged oppositely;

[0034] When the SY114 solenoid valve is opened, the gas enters the SY114 connection seat through the intake valve, then enters the trachea joint through the trachea connector, passes through the connected trachea cylinder mounting seat, and finally enters the first cylinder and the second cylinder;

[0035] The guide rod tops of the first cylinder and the second cylinder can contact the ballbar base housing to fix the ballbar base.

[0036] Further, the cylinder mounting seat includes a cylinder connecting seat, a ballbar base connecting ball positioning seat, and a ballbar base magnet;

[0037] The cylinder connection seat is a cylindrical rod body, which is used to be connected to the first cylinder and the second cylinder. The ballbar base connection ball positioning seat and the ballbar base magnet are arranged on the upper part of the cylinder connection seat. The ballbar base connection ball positioning seat is used to match and fix with the spherical surface of the ballbar base connection ball. The ballbar base magnet is arranged below the ballbar base connection ball positioning seat. The ballbar base magnet is used to magnetically fix the ballbar base on the ballbar body.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The three-dimensional ballbar provided by the present invention is low-cost, easy to transport, highly accurate, easy to operate, and of high practical value, and has the function of measuring the end error of a robot.

[0040] (2) The three-dimensional ballbar of the present invention has two measurement modes: when the ballbar base is ventilated and clamped, and only the ballbar body is used for measurement, the three-dimensional ballbar can be used to measure the distance error along the length of the ballbar; when the ballbar body is self-locking and the ballbar base is not ventilated, the ballbar body can be regarded as a bar of fixed length, and the three-dimensional ballbar can be used to measure the position error in the three directions of X, Y and Z. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the overall structure of a three-dimensional ballbar provided in Example 1 of the present invention;

[0042] Figure 2 A cross-sectional view of a tool cup device of a three-dimensional ballbar provided in Example 1 of the present invention;

[0043] Figure 3 A schematic diagram of the structure of a ballbar main body device of a three-dimensional ballbar provided in Embodiment 1 of the present invention with the ballbar main body shell removed;

[0044] Figure 4 A cross-sectional view of a ballbar body device of the three-dimensional ballbar provided in Embodiment 1 of the present invention with the ballbar body shell removed;

[0045] Figure 5 A schematic diagram of a self-locking state of a ballbar body device of a three-dimensional ballbar provided in Embodiment 1 of the present invention;

[0046] Figure 6 A schematic diagram of a ballbar body device of a three-dimensional ballbar provided in embodiment 1 of the present invention in a non-self-locking state;

[0047] Figure 7 A schematic structural diagram of a ballbar body leaf spring A of a ballbar body device of a three-dimensional ballbar provided in Embodiment 1 of the present invention;

[0048] Figure 8 A schematic structural diagram of a ballbar body leaf spring B of a ballbar body device of a three-dimensional ballbar provided in Embodiment 1 of the present invention;

[0049] Fig. 9 A front view of the structure of the ballbar base device of the three-dimensional ballbar provided in Embodiment 1 of the present invention after removing the ballbar base shell and the ballbar base upper shell;

[0050] Fig.10 A rear view of the structure of the ballbar base device of the three-dimensional ballbar provided in Embodiment 1 of the present invention after removing the ballbar base shell and the ballbar base upper shell;

[0051] Fig.11 A cross-sectional view of a gravity balance device of a ballbar base device of a three-dimensional ballbar provided in Embodiment 1 of the present invention;

[0052] Fig.12 A schematic structural diagram of a gravity balancing device of a ballbar base device of a three-dimensional ballbar provided in Embodiment 1 of the present invention;

[0053] Fig.13 A schematic diagram of the structure of a clamping mechanism of a ballbar base device of a three-dimensional ballbar provided in Example 1 of the present invention;

[0054] Fig.14 A cross-section view of the cylinder mounting assembly of the ballbar base assembly of the provided 3D ballbar.

[0055] The names corresponding to the reference numerals in the accompanying drawings are: 1- tool cup; 2- ballbar body; 3- ballbar base; 4- tool cup connecting ball; 5- ballbar body shell; 6- ballbar base connecting ball; 7- ballbar base upper shell; 8- ballbar base shell; 9- air inlet valve; 10- ballbar base lower shell; 11- ball positioning seat; 12- tool cup mounting seat; 13- tool cup magnet; 14- tool cup ball mounting seat; 15- ballbar body magnetic core; 16- ballbar body leaf spring A fixed; 17- ballbar body leaf spring A; 18- ballbar body leaf spring frame; 19- ballbar body coil; 20- ballbar body leaf spring support; 21- fixing pin; 22- ballbar body leaf spring B; 23- ballbar body leaf spring B fixed; 24- damping cavity; 25- self-locking screw; 26- ballbar body data receiver structure; 27-ballbar body upper shell; 28-cylinder connection seat; 29-first cylinder; 30-XY leaf spring fixing seat; 31-Y direction leaf spring A; 32-Y direction leaf spring B; 33-X direction leaf spring A; 34-Z leaf spring upper fixing plate; 35-Z direction leaf spring A; 36-Z leaf spring fixing plate A; 37-Z leaf spring fixing plate B; 38-Z direction leaf spring B; 39-overall mounting seat; 40-tracheal joint; 41- Air pipe connector; 42-bearing mounting plate; 43-gravity balance spring; 44-screw nut; 45-screw; 46-SY114 connecting seat; 47-SY114 solenoid valve; 48-motor; 49-X-direction leaf spring B; 50-bearing A; 51-bearing B; 52-second cylinder; 53-ballbar base connecting ball positioning seat; 54-ballbar base magnet; 55-ballbar base data receiving mechanism. DETAILED DESCRIPTION

[0056] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are implemented based on the above technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0057] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0058] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0059] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limitations on this patent: in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0060] In the following implementation modes or examples, unless otherwise specified, features such as structure / module name, control mode, algorithm, process or composition ratio are deemed to be common technical features disclosed in the prior art.

[0061] Example 1

[0062] See also Figure 1-8 , this embodiment provides a three-dimensional ballbar for measuring end error, characterized in that the three-dimensional ballbar consists of three parts: a tool cup 1, a ballbar body 2 and a ballbar base 3;

[0063] The tool cup 1 includes a ball positioning seat 11, a tool cup mounting seat 12, and a tool cup magnet 13;

[0064] The ballbar body 2 comprises: a tool cup connecting ball 4 and a ballbar base connecting ball 6 respectively arranged at both ends of the ballbar body 2, a ballbar body housing 5, a ballbar body measuring mechanism, a ballbar body data receiving mechanism 26, and a ballbar body upper housing 27;

[0065] The tool cup mounting base 12 is connected to the end effector of the robot or the spindle of the machine tool, the tool cup 1 is magnetically connected to the ballbar body 2 via the tool cup connecting ball 4, and the ballbar body 2 is magnetically connected to the ballbar base 3 via the ballbar base connecting ball 6;

[0066] The ballbar body 2 has a measurement function along the length of the bar, and the ballbar base 3 has a measurement function in three directions: X, Y, and Z.

[0067] See also Figure 2 The ball positioning 11 is used to match and connect with the spherical surface of the tool cup connecting ball 4, the tool cup mounting seat 12 is used to connect with the end of the robot or the spindle of the machine tool, and the tool cup magnet 13 is used to magnetically fix the tool cup 1 on the ballbar body 2.

[0068] See also Figure 3-8 The ballbar body measuring mechanism is fixedly connected to the tool cup connecting ball 4 via the tool cup ball mounting seat 14, and the tool cup connecting ball 4 is threadedly connected to the tool cup ball mounting seat 14;

[0069] The ballbar body measuring mechanism includes a ballbar body magnetic core 15, a ballbar body coil 19, a ballbar body leaf spring A fixing 16, a ballbar body leaf spring A17, a ballbar body leaf spring frame 18, a ballbar body leaf spring support 20, a fixing pin 21, a ballbar body leaf spring B22, a ballbar body leaf spring B fixing 23, a damping cavity 24, and a self-locking screw 25.

[0070] The ballbar body magnetic core 15 is threadedly connected to the tool cup ball mounting seat 14, and the ballbar body coil 19 is arranged around the ballbar body magnetic core 15. The ballbar body coil 19 is electrically connected to the ballbar body data receiving mechanism 26. When the ballbar body magnetic core 15 moves, the magnetic flux in the ballbar body coil 19 is changed, thereby inducing a current and an induced voltage in the ballbar body coil 19. Then, the ballbar body coil 19 can conduct the generated electrical signal to the ballbar body data receiving mechanism 26.

[0071] The ballbar body leaf spring frame 18 is arranged in a ring shape with the ballbar body leaf spring support 20 as the center. The top of the ballbar body leaf spring support 20 is glued to the tool cup ball mounting seat 14, and the bottom of the ballbar body leaf spring support 20 is glued to the damping cavity 24. The inner circles of the ballbar body leaf spring A17 and the ballbar body leaf spring B22 are sleeved on the ballbar body leaf spring support 20. The outer circle of the ballbar body leaf spring A17 is arranged between the ballbar body leaf spring A fixing 16 and the ballbar body leaf spring frame 18. The ballbar body leaf spring A17 is fixed to the ballbar body leaf spring frame 18 by screws. The outer circle of the ballbar body leaf spring B22 is arranged between the ballbar body leaf spring B fixing 23 and the ballbar body leaf spring frame 18. The ballbar body leaf spring B22 is fixed to the ballbar body leaf spring frame 18 by screws.

[0072] The fixing pin 21 passes through the leaf spring support 20 of the ballbar body, and both ends of the fixing pin 21 are fixedly connected to the leaf spring frame 18 of the ballbar body, so as to limit the movement direction to the length direction of the ballbar body;

[0073] The flat ends of the self-locking screw 25 are fixed to the two ends of the bottom of the ballbar body leaf spring B fixing 23 , and the tip of the self-locking screw 25 can be inserted into the damping cavity 24 to achieve locking of the ballbar body 2 .

[0074] See also Fig. 9 and 10 The ballbar base 3 includes a ballbar base upper shell 7, a ballbar base shell 8, a ballbar base lower shell 10, a first parallel leaf spring mechanism, a second parallel leaf spring mechanism, a third parallel leaf spring mechanism, a gravity balance mechanism, a tightening mechanism, and a ballbar base data receiving mechanism 55;

[0075] In this embodiment, the limited movement direction of the first parallel leaf spring mechanism is defined as the X direction, the limited movement direction of the second parallel leaf spring mechanism is the Y direction, and the limited movement direction of the third parallel leaf spring mechanism is the Z direction;

[0076] The first parallel leaf spring mechanism comprises an XY leaf spring fixing seat 30, an X-direction leaf spring A33, an X-direction leaf spring B49, an X-direction coil of a ballbar base, and an X-direction magnetic core of a ballbar base;

[0077] The second parallel leaf spring mechanism comprises an XY leaf spring fixing seat 30, a Y-direction leaf spring A31, a Y-direction leaf spring B32, a Y-direction coil of a ballbar base, and a Y-direction magnetic core of a ballbar base;

[0078] The third parallel leaf spring mechanism includes a Z-spring upper fixing plate 34, a Z-direction leaf spring A35, a Z-spring fixing plate A36, a Z-spring fixing plate B37, a Z-direction leaf spring B38, a ballbar base Z-direction coil, and a ballbar base Z-direction magnetic core;

[0079] The XY leaf spring fixing seat 30 is a cube, the X-direction leaf spring A33 and the X-direction leaf spring B49 are respectively fixed on the front and rear surfaces of the XY leaf spring fixing seat 30, and the Y-direction leaf spring A31 and the Y-direction leaf spring B32 are respectively fixed on the left and right surfaces of the XY leaf spring fixing seat 30;

[0080] The Z spring upper fixing plate 34 is connected to the bottom of the XY leaf spring fixing seat 30, the Z-direction leaf spring A35 and the Z-direction leaf spring B38 are arranged parallel to the Z spring upper fixing plate 34, the Z spring fixing plate A36 and the Z spring fixing plate B37 are arranged vertically to the Z spring upper fixing plate 34, and the Z spring fixing plate A36 and the Z spring fixing plate B37 are used to support and fix the Z-direction leaf spring A35 and the Z-direction leaf spring B38;

[0081] Each of the three groups of parallel leaf spring mechanisms is composed of a group of parallel movable plates and a group of parallel leaf springs. Since the middle of the leaf spring is thicker than the two sides close to the fixed plate and the movable plate, the stiffness of the middle of the leaf spring is greater than the two sides close to the fixed plate and the movable plate. Therefore, the leaf spring in the middle part no longer undergoes elastic deformation; the cylinder connecting seat 28 drives the movable plate to move under the action of external force. Since the stiffness of the cylinder connecting seat 28 is much greater than the stiffness of the leaf spring, the parallel leaf spring mechanism is deformed under the action of external force, resulting in relative movement between the movable plate and the fixed plate. Within ±3mm, the deformation of the leaf spring is linear deformation.

[0082] The X, Y and Z directions of the ballbar base 3 are respectively provided with X, Y and Z direction magnetic cores and coils matched with the magnetic cores. The X and Y direction coils of the ballbar base are arranged inside the XY leaf spring fixing seat 30, and the X direction coil is perpendicular to the X direction leaf spring A33 and the X direction leaf spring B49. The X direction magnetic core is arranged at the center of the X direction coil. The Y direction coil is perpendicular to the Y direction leaf spring A31 and the Y direction leaf spring B32. The Y direction magnetic core is arranged at the center of the Y direction coil. The Z direction coil is installed on the Z direction spring fixing plate A36, and the Z direction coil is perpendicular to the Z direction leaf spring A35 and the Z direction leaf spring B38. The Z direction magnetic core is arranged at the center of the Z direction coil. The ballbar base coils are all electrically connected to the ballbar base data receiving mechanism 55. When the ballbar base magnetic core moves, the ballbar base coil can transmit the generated electrical signal to the ballbar base data receiving mechanism 55.

[0083] See also Fig.11 and 12 The gravity balance of the gravity balance mechanism of the three-dimensional ballbar base 3 is achieved by the elastic force of the compression spring. The gravity balance mechanism includes an overall mounting seat 39, a bearing mounting plate 42, two gravity balance springs 43, a screw nut 44, a screw 45, a motor 48, a bearing A50, and a bearing B51;

[0084] The upper ends of the two gravity balance springs 43 are inserted into the two round holes on the Z spring fixing plate B37, and the motor 48 is fixedly mounted on the overall mounting seat 39;

[0085] The outer ring of the bearing A50 is fixedly mounted on the bearing mounting plate 42, the upper end of the screw rod 45 can be inserted into the inner ring of the bearing A50, and the lower end of the screw rod 45 is connected to the output shaft of the motor 48, and the motor 48 is used to drive the screw rod 45 to rotate;

[0086] The middle hole of the screw nut 44 is threadedly connected to the screw 45. Two cylinders for inserting the gravity balance spring 43 are provided at both ends of the screw nut 44. The screw nut 44 abuts against the lower end of the gravity balance spring 43. When the ballbar accessories are replaced, the gravity changes, and the Z-direction indication changes at this time. The rotation of the motor 48 drives the screw 45 to rotate, thereby making the threads between the screw 45 and the screw nut 44 cooperate. When the screw nut 44 moves upward with the screw 15, it squeezes the gravity balance spring 43, so that the two ends of the gravity balance spring 43 respectively support the Z spring fixing plate B37 and the screw nut 44 to balance the overall weight.

[0087] In this embodiment, the motor 48 is a brushed DC motor.

[0088] See also Fig.13The overall self-locking of the ballbar base 3 is pneumatic. The tightening mechanism includes an air inlet valve 9, a SY114 solenoid valve 47, a SY114 connection seat 46, an air pipe connector 41, an air pipe joint 40, a first air cylinder 29, a second air cylinder 52, and a cylinder mounting seat;

[0089] The SY114 solenoid valve 47 and the SY114 connecting seat 46 are arranged on the overall mounting seat 39, the air intake valve 9 and the air pipe connecting piece 41 are fixedly connected to the SY114 connecting seat 46, and the air pipe joint 40 is fixedly installed on the upper end of the air pipe connecting piece 41, and the first cylinder 29 and the second cylinder 52 are arranged at the bottom of the cylinder mounting seat, and the two cylinders are arranged opposite to each other;

[0090] When the SY114 solenoid valve 47 is opened, the gas enters the SY114 connection seat 46 through the intake valve 9, and then enters the gas pipe joint 40 through the gas pipe connector 41. The gas is connected to the cylinder mounting seat by the gas, and finally enters the first cylinder 29 and the second cylinder 52 to push the piston;

[0091] The guide rod tops of the first cylinder 29 and the second cylinder 52 can contact the ball bar base housing 8 so that the ball bar base 3 is fixed.

[0092] When the SY114 solenoid valve 47 is closed, the spring system of the cylinder discharges the gas from the cylinder, through the air pipe connector 41 and then through the exhaust port of the SY114 connector 46, releasing the self-locking of the ballbar base 3.

[0093] See also Fig.14 The cylinder mounting seat includes a cylinder connecting seat 28, a ballbar base connecting ball positioning seat 53, and a ballbar base magnet 54;

[0094] The cylinder connection seat 28 is a cylindrical rod body, which is used to connect with the first cylinder 29 and the second cylinder 52. The ballbar base connection ball positioning seat 53 and the ballbar base magnet 54 are arranged on the upper part of the cylinder connection seat 28. The ballbar base connection ball positioning seat 53 is used to match and fix with the spherical surface of the ballbar base connection ball 6. The ballbar base magnet 54 is arranged below the ballbar base connection ball positioning seat 53. The ballbar base magnet 54 is used to magnetically fix the ballbar base 3 on the ballbar body 2.

[0095] It should be noted that the ballbar body data receiving mechanism 26 and the ballbar base data receiving mechanism 55 in this embodiment are specifically signal analysis boards; and the gases are all dry air.

[0096] The two measurement modes of the 3D ballbar provided in this embodiment are as follows:

[0097] (1) The ballbar base 3 is self-locking and only the ballbar body 2 is used for measurement: Figure 6 As shown, at this time, the self-locking screw 25 of the ballbar is not inserted into the damping cavity 24, the air is passed into the air inlet valve 9, and the cylinder squeezes the ballbar base shell 8. When the cylinder is inflated, the push rods at both ends are pushed out and frictionally contact with the shell to make the ballbar base 3 self-locking. The three-dimensional ballbar can be used to measure the distance error along the length of the rod. When an error occurs at the end of the robot, the distance between the center of the tool cup connecting ball 4 and the ball bar base connecting ball 6 provided at both ends of the ball bar body 2 changes, and the tool cup 1 generates tension. Since the stiffness of the ball bar body leaf spring A17 and the ball bar body leaf spring B22 is relatively small, the middle part of the ball bar body leaf spring A17 and the ball bar body leaf spring B22 can deform accordingly when the tool cup ball mounting seat 14 is subjected to force. The fixing pin 21 is inserted in the middle of the ball bar body leaf spring support 20 to limit the movement direction to the rod length direction. At this time, the ball bar body magnetic core 15 and the ball bar body coil 19 move relative to each other to generate an electrical signal. The ball bar body coil 19 transmits the generated electrical signal to the ball bar body data receiving mechanism 26. The distance error of the robot end can be recorded by the ball bar body data receiving mechanism 26.

[0098] (2) The ballbar body 2 is self-locking and only uses the X, Y, Z measurement method of the ballbar base 3: Figure 5 As shown, at this time, the self-locking screw 25 of the ballbar is inserted into the damping cavity 24, and the ballbar base 3 is not ventilated, the linear movement of the ballbar body 2 will be restricted, the ballbar body 2 can be regarded as a rod of fixed length, the cylinder connector 28 of the ballbar base 3 can move, and the three-dimensional ballbar can be used to measure position errors in the three directions of X, Y, and Z. When an error occurs at the end of the robot, the length of the ballbar body 2 is constant, the tool cup 1 pulls the ballbar body 2, and the ballbar body 2 pulls the cylinder connector 28 of the ballbar base 3. After the cylinder connector 28 is subjected to force, it pulls the leaf springs in the X, Y, and Z directions and deforms. The ballbar base 3 has X, Y, and Z magnetic cores and coils in the X, Y, and Z directions, respectively, which cause relative movement of the three groups of ballbar base coils and the magnetic cores around the ballbar base and generate electrical signals. The ballbar base coils transmit the generated electrical signals to the ballbar base data receiving mechanism 55, and the position error of the robot end can be recorded by the ballbar base data receiving mechanism 55.

[0099] The above description of the embodiments is to facilitate the understanding and use of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A three-dimensional ballbar for measuring end-point error, characterized in that: The three-dimensional ballbar is composed of three parts: a tool cup (1), a ballbar body (2) and a ballbar base (3); The tool cup (1) comprises a ball positioning seat (11), a tool cup mounting seat (12), and a tool cup magnet (13); The ballbar body (2) comprises: a tool cup connecting ball (4) and a ballbar base connecting ball (6) respectively arranged at two ends of the ballbar body (2), a ballbar body shell (5), a ballbar body measuring mechanism, a ballbar body data receiving mechanism (26), and a ballbar body upper shell (27); The tool cup mounting seat (12) is connected to the execution end of the robot or the main shaft of the machine tool, the tool cup (1) is magnetically connected to the ballbar body (2) via the tool cup connecting ball (4), and the ballbar body (2) is magnetically connected to the ballbar base (3) via the ballbar base connecting ball (6); The ballbar body (2) has a measurement function along the length direction of the bar, and the ballbar base (3) has a measurement function in three directions: X, Y and Z.

2. A three-dimensional ballbar for measuring end-point error according to claim 1, characterized in that: The ball positioning seat (11) is used to match and connect with the spherical surface of the tool cup connecting ball (4), the tool cup mounting seat (12) is used to connect with the execution end of the robot or the main shaft of the machine tool, and the tool cup magnet (13) is used to magnetically fix the tool cup (1) on the ballbar body (2).

3. A three-dimensional ballbar for measuring end-point error according to claim 1, characterized in that: The ballbar body measuring mechanism is fixedly connected to the tool cup connecting ball (4) via a tool cup ball mounting seat (14), and the tool cup connecting ball (4) is threadedly connected to the tool cup ball mounting seat (14); The ballbar body measuring mechanism comprises a ballbar body magnetic core (15), a ballbar body coil (19), a ballbar body leaf spring A fixing (16), a ballbar body leaf spring A (17), a ballbar body leaf spring frame (18), a ballbar body leaf spring support (20), a fixing pin (21), a ballbar body leaf spring B (22), a ballbar body leaf spring B fixing (23), a damping cavity (24), and a self-locking screw (25).

4. A three-dimensional ballbar for measuring end-point error according to claim 3, characterized in that: The ballbar body magnetic core (15) is threadedly connected to the tool cup ball mounting seat (14); the ballbar body coil (19) is arranged around the ballbar body magnetic core (15); the ballbar body coil (19) is electrically connected to a ballbar body data receiving mechanism (26); when the ballbar body magnetic core (15) moves, the ballbar body coil (19) can conduct the generated electrical signal to the ballbar body data receiving mechanism (26); The ballbar body leaf spring frame (18) is arranged in a ring shape with the ballbar body leaf spring support (20) as the center. The top of the ballbar body leaf spring support (20) is glued to the tool cup ball mounting seat (14), and the bottom of the ballbar body leaf spring support (20) is glued to the damping cavity (24). The inner circles of the ballbar body leaf spring A (17) and the ballbar body leaf spring B (22) are sleeved on the ballbar body leaf spring support (20). The outer circle of the ballbar body leaf spring A (17) is arranged between the ballbar body leaf spring A fixing (16) and the ballbar body leaf spring frame (18), the ballbar body leaf spring A (17) is fixed to the ballbar body leaf spring frame (18) by screws, the outer circle of the ballbar body leaf spring B (22) is arranged between the ballbar body leaf spring B fixing (23) and the ballbar body leaf spring frame (18), the ballbar body leaf spring B (22) is fixed to the ballbar body leaf spring frame (18) by screws; The fixing pin (21) passes through the leaf spring support (20) of the ballbar body, and the two ends of the fixing pin (21) are fixedly connected to the leaf spring frame (18) of the ballbar body, so as to limit the movement direction to the length direction of the ballbar body; The flat ends of the self-locking screw (25) are fixed to the two ends of the bottom of the ballbar body leaf spring B fixing (23), and the tip of the self-locking screw (25) can be inserted into the damping cavity (24) to achieve locking of the ballbar body (2).

5. The three-dimensional ballbar for measuring end-point error according to claim 1, characterized in that: The ballbar base (3) comprises a ballbar base upper shell (7), a ballbar base shell (8), a ballbar base lower shell (10), a first parallel leaf spring mechanism, a second parallel leaf spring mechanism, a third parallel leaf spring mechanism, a gravity balancing mechanism, a tightening mechanism, and a ballbar base data receiving mechanism (55).

6. A three-dimensional ballbar for measuring end-point error according to claim 5, characterized in that: The first parallel leaf spring mechanism, the second parallel leaf spring mechanism, and the third parallel leaf spring mechanism are parallelogram mechanisms in three directions respectively, the limited movement direction of the first parallel leaf spring mechanism is defined as the X direction, the limited movement direction of the second parallel leaf spring mechanism is the Y direction, and the limited movement direction of the third parallel leaf spring mechanism is the Z direction; The first parallel leaf spring mechanism comprises an XY leaf spring fixing seat (30), an X-direction leaf spring A (33), an X-direction leaf spring B (49), an X-direction coil of a ballbar base, and an X-direction magnetic core of a ballbar base; The second parallel leaf spring mechanism comprises an XY leaf spring fixing seat (30), a Y-direction leaf spring A (31), a Y-direction leaf spring B (32), a Y-direction coil of a ballbar base, and a Y-direction magnetic core of a ballbar base; The third parallel leaf spring mechanism comprises a Z-spring upper fixing plate (34), a Z-direction leaf spring A (35), a Z-spring fixing plate A (36), a Z-spring fixing plate B (37), a Z-direction leaf spring B (38), a ballbar base Z-direction coil, and a ballbar base Z-direction magnetic core; The XY leaf spring fixing seat (30) is a cube, the X-direction leaf spring A (33) and the X-direction leaf spring B (49) are respectively fixed on the front and rear surfaces of the XY leaf spring fixing seat (30), and the Y-direction leaf spring A (31) and the Y-direction leaf spring B (32) are respectively fixed on the left and right surfaces of the XY leaf spring fixing seat (30); The Z-spring upper fixing plate (34) is connected to the bottom of the XY leaf spring fixing seat (30); the Z-direction leaf spring A (35) and the Z-direction leaf spring B (38) are arranged parallel to the Z-spring upper fixing plate (34); the Z-spring fixing plate A (36) and the Z-spring fixing plate B (37) are arranged perpendicular to the Z-spring upper fixing plate (34); the Z-spring fixing plate A (36) and the Z-spring fixing plate B (37) are used to support and fix the Z-direction leaf spring A (35) and the Z-direction leaf spring B (38); The ballbar base (3) has X, Y, and Z direction magnetic cores and coils matched with the magnetic cores in the X, Y, and Z directions respectively. The ballbar base X and Y direction coils are arranged inside an XY leaf spring fixing seat (30), and the X direction coil is perpendicular to an X direction leaf spring A (33) and an X direction leaf spring B (49). The X direction magnetic core is arranged at the center of the X direction coil. The Y direction coil is perpendicular to a Y direction leaf spring A (31) and a Y direction leaf spring B (32). The Y direction magnetic core is arranged at the center of the Y direction coil. The Z direction coil is installed on a Z direction leaf spring fixing plate A (36), and the Z direction coil is perpendicular to a Z direction leaf spring A (35) and a Z direction leaf spring B (38). The Z direction magnetic core is arranged at the center of the Z direction coil. The ballbar base coils are all electrically connected to a ballbar base data receiving mechanism (55). When the ballbar base magnetic core moves, the ballbar base coil can transmit the generated electrical signal to the ballbar base data receiving mechanism (55).

7. A three-dimensional ballbar for measuring end-point error according to claim 5, characterized in that: The gravity balancing mechanism comprises an overall mounting seat (39), a bearing mounting plate (42), two gravity balancing springs (43), a screw nut (44), a screw (45), a motor (48), a bearing A (50), and a bearing B (51); The upper ends of the two gravity balance springs (43) are inserted into the two circular holes on the Z spring fixing plate B (37), and the motor (48) is fixedly mounted on the overall mounting seat (39); The outer ring of the bearing A (50) is fixedly mounted on the bearing mounting plate (42), the upper end of the screw rod (45) can be inserted into the inner ring of the bearing A (50), and the lower end of the screw rod (45) is connected to the output shaft of the motor (48), and the motor (48) is used to drive the screw rod (45) to rotate; The middle hole of the screw nut (44) is threadedly connected to the screw rod (45), and two cylinders for inserting the gravity balance spring (43) are provided at both ends of the screw nut (44). The screw nut (44) abuts against the lower end of the gravity balance spring (43). The rotation of the motor (48) drives the screw rod (45) to rotate, thereby making the threads between the screw rod (45) and the screw nut (44) match. When the screw rod (45) moves upward, the screw nut (44) presses the gravity balance spring (43), so that the two ends of the gravity balance spring (43) respectively support the Z spring fixing plate B (37) and the screw nut (44) to balance the overall weight.

8. A three-dimensional ballbar for measuring end-point error according to any one of claim 7, characterized in that: The motor (48) is a direct current brushed motor.

9. A three-dimensional ballbar for measuring end-point error according to claim 5, characterized in that: The tightening mechanism comprises an air intake valve (9), a SY114 solenoid valve (47), a SY114 connecting seat (46), an air pipe connecting piece (41), an air pipe joint (40), a first air cylinder (29), a second air cylinder (52), and a cylinder mounting seat; The SY114 solenoid valve (47) and the SY114 connecting seat (46) are arranged on the overall mounting seat (39), the air intake valve (9) and the air pipe connecting piece (41) are fixedly connected to the SY114 connecting seat (46), the upper end of the air pipe connecting piece (41) is fixedly mounted with an air pipe joint (40), the first cylinder (29) and the second cylinder (52) are arranged at the bottom of the cylinder mounting seat, and the two cylinders are arranged opposite to each other; When the SY114 solenoid valve (47) is opened, the gas enters the SY114 connection seat (46) through the intake valve (9), then enters the trachea joint (40) through the trachea connection piece (41), and finally enters the first cylinder (29) and the second cylinder (52) through the connected trachea cylinder mounting seat; The guide rod tops of the first cylinder (29) and the second cylinder (52) can contact the ballbar base housing (8) so that the ballbar base (3) is fixed.

10. A three-dimensional ballbar for measuring end-point error according to claim 9, characterized in that: The cylinder mounting seat comprises a cylinder connecting seat (28), a ballbar base connecting ball positioning seat (53), and a ballbar base magnet (54); The cylinder connection seat (28) is a cylindrical rod body, used to be connected to the first cylinder (29) and the second cylinder (52); the ballbar base connection ball positioning seat (53) and the ballbar base magnet (54) are arranged on the upper part of the cylinder connection seat (28); the ballbar base connection ball positioning seat (53) is used to match and fix with the spherical surface of the ballbar base connection ball (6); the ballbar base magnet (54) is arranged below the ballbar base connection ball positioning seat (53); the ballbar base magnet (54) is used to magnetically fix the ballbar base (3) to the ballbar body (2).

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