An easy-to-use robotic arm teaching system with force feedback

Abstract

The present invention discloses an easy-to-use mechanical arm teaching system with force feedback, including a teaching frame, a mechanical arm and an extrusion sensor. The teaching frame includes a main controller with a touch screen, a teaching gun, and mechanical joints corresponding to human hand joints. The inverted U hook 1 and the inverted U hook 2 on the mechanical joint are mounted on the forearm of the instructor. The joint as a whole and the arm follow, and the arm movement trajectory can be sensed, and used to teach the mechanical arm. The extrusion sensor can sense the force and direction of the extrusion of the electric tool at the end of the mechanical arm and the workpiece, and the main controller controls the three-degree-of-freedom tail plate on the gun handle of the teaching gun to deflect forward, backward, left, right, and up and down, and feedback the magnitude and direction of the extrusion force to the instructor in real time, so that the feel of the teaching process is similar to the actual manual processing process. For skilled workers, they only need to hold the teaching gun and imitate the working method to quickly complete the teaching. This teaching system does not require programming or computer operation, and achieves efficient teaching with a teaching time close to the processing time of a single workpiece.

Description

Technical Field

[0001] The invention belongs to the technical field related to automated mechanical teaching, and in particular relates to an easy-to-use mechanical arm teaching system with force feedback. Background Art

[0002] Robotic arms have gradually entered all walks of life, replacing manual labor to complete complicated labor and improving productivity. However, when entering small and medium-sized enterprises, there is a big teaching bottleneck. The operation of the robotic arm requires controlling the motion trajectory of the robotic arm and the force of the power tool carried by the robotic arm. Most of the current teaching tools cannot start the power tool for practical teaching. Because the contact force between the power tool and the workpiece cannot be fed back, starting the tool is prone to dangerous situations. Therefore, the teaching process is to first generate a complete teaching trajectory, and then the robotic arm carries the power tool to perform a trial run according to the trajectory, observe the processing effect, and then modify it, and then run it again, and so on, which takes a lot of time. For complex workpieces, it even appears that processing only takes a few minutes, but the actual situation of teaching programming takes several days.

[0003] Small and medium-sized enterprises need teaching tools that can easily convert employees' skilled techniques into robot arm movements. Especially for non-standard components with only dozens or hundreds of them, it can achieve the teaching efficiency of processing workpieces in just a few minutes and the teaching process in just a few minutes, making the robot arm truly practical.

[0004] However, although there are many teaching methods, there are still many difficulties in use, such as:

[0005] The method of teaching by inputting instructions line by line on the keyboard is low-cost and highly compatible, and has been widely used. However, it has high requirements for programmers, who need to systematically learn the usage of various instructions. In actual teaching programming, it is only suitable for occasions where the robot arm has a single action and few trajectory changes. For trajectory programming without specified action rules, such as spraying teaching for workpieces with many dark corners such as fake trees, the teaching efficiency is very low. The programming ability of the instructor and his understanding of the action will also lead to uneven teaching results.

[0006] Patent [CN100581753] proposes a method of building a robot model and teaching by moving the end of the robot model. This method does not require programming and can quickly obtain accurate teaching trajectories. However, the model must have the same degrees of freedom, the same type and number of hinges, the same mechanism size, and the same workspace as the robot. Because the model itself does not have a gravity compensation device, the weight of the model is a serious problem for manual teaching. The teaching handle is on the outside of the end joint. When the end joint needs to be rotated more than 180 degrees by hand, the operation is very difficult or even impossible because the model blocks the hand.

[0007] Patent [CN104552300B] proposes a teaching model based on a base and a number of joint arms arranged in series on the base, and teaching is performed by manually driving the model. Teaching is intuitive, but the teaching model itself has its own weight. In order to prevent sagging, a gravity compensation device and a damper are added. However, these devices also restrict flexibility and are laborious to operate. The joints of the teaching model are not in a one-to-one correspondence with the human arm. The first joint of the model starts from the base, while the first joint of the human arm starts from the shoulder. The joints of the model and the joints of the human hand are not in a follow-up relationship. During the mobile teaching, because it is not completely equivalent to the daily working method, the teaching personnel will feel awkward, the teaching action rhythm is not good, and it is difficult to simply imitate the daily skilled operation process. And this structural difference may cause the human body or arm to be blocked by the model, and the problem of being unable to perform flexible movements. In order to stabilize the teaching, the whole machine must have a heavier chassis or be fixed to the ground, which limits the mobility of the teaching model itself.

[0008] Patent [CN110605721] and others proposed a robot arm dragging teaching method based on a multi-dimensional force sensor at the end. For this method, the instructor directly drags the real working robot arm. The instructor stands next to the robot arm and holds the robot arm in his hand. For safety reasons, the power tools of the robot arm cannot be powered on for practical teaching, because the power tools are at hand and may hurt people. The instructor must teach once, then start the power tool for a trial run to see the processing effect, and then adjust the teaching trajectory, and repeat this many times. During the teaching, people stand in the working space of the robot arm. If the control is improper, it is also easy for the robot arm to injure people. At present, this teaching method has been gradually discontinued for industrial robot arms.

[0009] Patent [CN107309882B] proposes to use high-speed cameras such as Optitrack to capture marking points and teach through moving trajectories. This mode requires the deployment of professional cameras and light sources at fixed points in the teaching environment, as well as a host capable of three-dimensional calculations. The entire system is costly and has many accessories. The environment layout and debugging require professional teaching personnel who are very familiar with the teaching system. This mode is extremely difficult for ordinary low-educated employees. The biggest problem with optical capture is that for workpieces with deeper depressions such as pipes, furniture, sanitary ware, and crafts, they cannot be captured due to line of sight obstruction, which directly affects the versatility of the teaching system.

[0010] Patent [CN107363813B] proposes a method for teaching using a mountable inertial sensor device. This method does not have the problem of the motion space being blocked. However, it is currently difficult to achieve millimeter-level spatial positioning accuracy, and the accuracy will increase with the accumulation of time. For robotic arms, the teaching accuracy of less than 0.1mm is generally required, which is difficult to achieve with the inertial sensor tracking method. In addition, the mountable inertial motion capture device needs to be mounted and calibrated complexly each time, which is time-consuming and requires high standards from the instructor.

[0011] The above teaching methods, and other teaching methods in actual work, mostly do not have teaching force feedback and over-force protection mechanisms, so practical teaching cannot be implemented for work that may contact the workpiece; however, in actual work, contact processing is more common than non-contact processing, and the inability to provide practical teaching has limited the further promotion of robotic arms. Summary of the invention

[0012] The purpose of the present invention is to provide an easy-to-use robotic arm teaching system with force feedback to solve the problems of the lack of teaching force feedback and over-force protection mechanism and the inability to perform practical teaching proposed in the above-mentioned background technology.

[0013] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an easy-to-use robotic arm teaching system with force feedback, comprising a teaching frame, a robotic arm and a squeeze sensor, the teaching frame comprising a main controller with a touch screen, a teaching gun, mechanical joints corresponding to human hand joints, and an inverted U hook 1 and an inverted U hook 2, the inverted U hook 1 and the inverted U hook 2 on the mechanical joints are correspondingly mounted on the forearm of the instructor, the joint as a whole and the arm follow, and are used to sense the movement trajectory of the arm, and the squeeze sensor is correspondingly installed at the end of the robotic arm joint.

[0014] Preferably, the touch screen installed on the main controller displays the teaching trajectory and touch buttons in real time, and the main controller is equipped with a voice recognition system and a built-in speaker.

[0015] Preferably, the first inverted U hook and the second inverted U hook are made of flexible metal with a rubber outer layer.

[0016] Preferably, the mechanical joints include arm rotation joint 1, arm swing joint 1, arm rotation joint 2, arm swing joint 2, arm rotation joint 3, arm swing joint 3 and arm swing joint 4, which correspond one-to-one to the arm joints of the instructor.

[0017] Preferably, the intersection of the tripod bracket and the arm swivel joint 1 is the coordinate origin of the teaching frame.

[0018] Preferably, the teaching stand further comprises a tripod bracket with adjustable height, and the tripod bracket is used to support the mechanical joint.

[0019] Preferably, the sensor includes an extrusion sensor fixed at the end of the working end of the robotic arm, and the extrusion sensor can sense the force and direction of the extrusion of the electric tool and the workpiece at the end of the robotic arm, and control the three-degree-of-freedom tail plate on the gun handle of the teaching gun to deflect forward, backward, left, right, up and down through the main controller, and provide real-time feedback on the size and direction of the extrusion force to the instructor. When the extrusion sensor detects an abnormal situation, it can control the robotic arm to stop urgently.

[0020] Preferably, a "proportional reduction extrusion depth teaching" button is provided on the touch screen, and the user starts the "proportional reduction extrusion depth teaching" mode by touching the button. After this mode is started, when the extrusion sensor detects that the extrusion value is greater than 0, this mode starts to start, so that the power tool proportionally reduces the extrusion depth of the workpiece.

[0021] Preferably, the teaching system also includes an "over-extrusion protection mechanism". During teaching, when the extrusion force approaches the safety limit value, the system can adjust the control coordinates to keep the extrusion force close to but not exceeding the limit value.

[0022] Compared with the existing robot arm teaching technology, the present invention provides an easy-to-use robot arm teaching system with force feedback, which has the following beneficial effects:

[0023] 1. The present invention can sense the force and direction of the extrusion between the electric tool at the end of the robot arm and the workpiece through the extrusion sensor, and can control the three-degree-of-freedom tail plate on the gun handle of the teaching gun to deflect forward, backward, left, right, up and down through the main controller, and feedback the magnitude and direction of the extrusion force to the instructor in real time, so that the feel of the teaching process is similar to the actual manual processing process. For skilled workers, they only need to hold the teaching gun and imitate the actual working method to quickly complete the teaching. This teaching system does not require programming or computer operation, and can quickly transmit the skilled worker's method to the robot arm, achieving efficient teaching with a teaching time close to the processing time of a single workpiece;

[0024] 2. The present invention is low-cost, light, portable, high-precision, simple and convenient to operate. Basically, all employees can perform intuitive teaching on the robotic arm teaching system. The outstanding feature is that the robotic arm can highly imitate the movements of human hands, especially the movements of the wrist, has force feedback, and can simultaneously open power tools such as spray guns, grinding heads, and dispensing nozzles to effectively teach the workpiece. The teaching is the actual processing effect of the robotic arm, and the teaching is what is obtained. For daily teaching, it only takes a few minutes to process a single workpiece, and the teaching process only takes a few minutes. Ordinary workers can also complete the teaching very efficiently, solving the problem of fast movement updates and difficult teaching of robotic arms in small and medium-sized enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 This is a practical operation diagram of an easy-to-use mechanical arm teaching system with force feedback proposed by the present invention;

[0027] Figure 2 This is a schematic diagram of the joint distribution structure proposed by the present invention;

[0028] Figure 3 This is a schematic diagram of the overall appearance of the arm swing joint proposed by the present invention;

[0029] Figure 4 This is a schematic diagram of the decomposed structure of the arm swing joint proposed by the present invention;

[0030] Figure 5 This is a schematic diagram of the T-shaped central axis cross-section structure proposed by the present invention;

[0031] Figure 6 This is a schematic diagram of the overall appearance of the arm swivel joint proposed by the present invention;

[0032] Figure 7 This is a schematic diagram of the decomposed structure of the arm rotation joint proposed by the present invention;

[0033] Figure 8 This is a schematic diagram of the cross-sectional structure of the arm rotation joint winding bin proposed by the present invention;

[0034] Fig. 9 This is a schematic diagram of the sliding joint structure proposed by the present invention;

[0035] Fig.10 This is a schematic diagram of the overall structure of the teaching gun proposed by the present invention;

[0036] Fig.11 This is a schematic diagram of the cross-sectional structure of the teaching gun proposed by the present invention;

[0037] Fig.12 This is a schematic diagram of the overall structure of the squeeze sensor proposed by the present invention;

[0038] Fig.13 This is a schematic diagram of the cross-sectional structure of the three-dimensional force sensor proposed by the present invention;

[0039] In the figure: M1, teaching frame; M2, mechanical arm; M3, extrusion sensor; M4, tripod bracket; M5, main controller; M6, teaching gun; M11, arm rotation joint 1; M12, arm swing joint 1; M13, arm rotation joint 2; M14, arm swing joint 2; M15, arm rotation joint 3; M16, arm swing joint 3; M17, arm swing joint 4; M18, sliding joint; M19, inverted U hook 1; M20, inverted U hook 2; M30, coordinate origin; Y1, through hole 1; Y2, through hole 2; Y3, through hole 3; Y4, through hole 4; Y5, through hole 5; Y6, through hole 6; Y7, through hole 7; Y8, connecting tube; T1, T-shaped center axis; T2, first code disk supporting magnetic steel; T3A, one outer jacket of the bearing; T4A, one bearing; T5A, one outer ring pressure ring of the bearing; T6A, one inner ring pressure piece of the bearing; T7-L, one Y-type clamp; T8, the first angle sensor code disk; T9A, one outer cover; T3B, two outer jackets of the bearing; T4B, two bearings; T5B, two outer ring pressure rings of the bearing; T6B, two inner ring pressure pieces of the bearing; T7-R, two Y-type clamps; T9B, two outer covers; Q1, raised round table; Q2, circular notch; Q3, screw hole; Q4, groove mouth; Q5, connection port; K1, main support frame; K2, sliding limit card; K3, magnetic steel limit bearing; K4, magnetic torque transmission sheet; K5, magnetic steel fixing rod; K6, second code disk supporting magnetic steel; K7, code disk fixing ring; K8, second angle sensor code disk; K11, stainless steel round tube limit bearing; K12, magnet sliding guide groove; K13, toothed metal magnetic strip; K14, rectangular magnet; K20, wiring card; K21, winding bin; K22, shell; K23, stainless steel round tube; K24, half-open ring; K25, electrical wiring; W1, threaded optical axis one; W2, linear sliding bearing one; W3, first spring; W4, optical axis tail buckle one; W5, displacement sensor; W6, fixing plate; W7, optical axis tail buckle two; W8, second spring; W9, linear sliding bearing two; W10, threaded optical axis two; W11, I-shaped main support frame; S1, teaching gun main shell body; S3, force feedback grip back plate; S4, emergency stop trigger; S5, main board; S6, retractable rubber guard; S7, limit bead; S8, spring limit plate; S9, cam; S11, cross universal joint one; S12, cross universal joint two; S13, cross universal joint three; S14, cross universal joint four; S21, servo motor one; S22, servo motor two; S23, servo motor three; F1, three-dimensional force sensor; F2, spring; F3, fixed plate one; F4, spring cover one; F5, displacement sensor; F6, spring cover two; F7, fixed plate two; F8, pressure sensor one; F9, pressure sensor two; F10, pressure sensor three; F11, shell. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figures 1 to 13 The present invention provides a technical solution: an easy-to-use mechanical arm teaching system with force feedback, comprising a teaching frame M1, a mechanical arm M2 and a squeeze sensor, the teaching frame M1 comprising a main controller M5 with a touch screen, a teaching gun M6, mechanical joints corresponding to human hand joints, and an inverted U hook M19 and an inverted U hook M20, the inverted U hook M19 and the inverted U hook M20 on the mechanical joints are correspondingly mounted on the forearm of the instructor, the joint as a whole and the arm follow-up, and are used to sense the movement trajectory of the arm, and the squeeze sensor is correspondingly installed at the end of the mechanical joint.

[0042] Furthermore, the touch screen installed on the main controller M5 displays the teaching trajectory and touch buttons in real time for the user to view and click. The main controller M5 is equipped with a voice recognition system and a built-in speaker, which can emit alarm buzzers and error voice prompts.

[0043] Furthermore, the inverted U hook 1 M19 and the inverted U hook 2 M20 are made of flexible metal with a rubber outer layer, which can be bent appropriately to change the shape. When teaching, the hook is hung on the forearm of the instructor, and the arm rotation joint M15 can move along with the forearm of the person.

[0044] Furthermore, the mechanical joints include arm rotation joint 1 M11, arm swing joint 1 M12, arm rotation joint 2 M13, arm swing joint 2 M14, arm rotation joint 3 M15, arm swing joint 3 M16 and arm swing joint 4 M17, which correspond one by one to the arm joints of the instructor, and correspond in sequence to the shoulder rotation, shoulder swing, upper arm rotation, elbow swing, forearm rotation, wrist vertical swing, and wrist outward swing of the instructor's arm.

[0045] It should be noted that the teaching stand M1 also includes a tripod bracket M4 with adjustable height. The tripod bracket M4 is used to support the mechanical joints, reduce the operating gravity, and facilitate the operator's operation.

[0046] It is worth noting that the intersection of the tripod bracket M4 and the arm rotation joint M11 is the coordinate origin M30 of the teaching frame M1. During the teaching operation, the coordinates of the end of the teaching gun M6 relative to the origin M30 and the spatial attitude angle of the teaching gun can be obtained through the rotation angle of each joint and the arm length of each arm after kinematics correct solution.

[0047] It should be understood that the arm swing joint 1 M12, arm swing joint 2 M14 and arm swing joint 3 M16 and arm swing joint 4 M17 have the same structure, and their components are generally symmetrical from the middle to the two sides, specifically: outer cover 1 T9A, angle sensor code disk T8, Y-type clamp 1 T7-L, bearing inner ring pressure plate 1 T6A, bearing outer ring pressure ring 1 T5A, bearing 1 T4A, bearing outer jacket 1 T3A, first code disk supporting magnetic steel T2, T-type center shaft T1, bearing outer jacket The first and second Y-type clamps T7-L and T7-R are actually an integral part. For the sake of convenience, they are schematically divided into two parts of a part. The Y-type clamp T7 is used to represent them. The A and B of other parts represent two separate devices, but the structures are the same. The T-shaped central axis T1 is shown in the cross-sectional view. Figure 5 As shown, there are raised cones Q1 on the left and right sides of the axis of this part, which can be used to sleeve bearing 1 T4A and bearing 2 T4B. There is a circular recess Q2 on the left side for fixing the first code disk supporting magnetic steel T2, and a recess Q4 on the right side, which is divided into two paths. The interior is hollow and connected to the lower tail and bottom of the T-shaped center axis T1 respectively, to achieve internal hollow wiring, avoid the unsightly wiring exposure, and prevent the problem of electrical wiring breaking when the joint rotates. There are screw holes Q3 on the raised cones Q1 on the left and right sides of the T-shaped center axis T1. When assembling, the screws are passed through the through holes Y5 of the bearing inner ring pressure plate 1 T6A and the bearing inner ring pressure plate 2 T6B and screwed to the screw holes Q3 to clamp the inner rings of bearing 1 T4A and bearing 2 T4B respectively, so that bearing 1 T4A and bearing 2 The inner ring T4B and the T-shaped middle axis T1 are connected as a whole. The outer sleeve T3A of the bearing and the outer sleeve T3B of the bearing are circular rings with an inward step at the tail and a threaded hole Y1. During assembly, the screws are passed through the through holes Y3 of the outer cover T9A and the outer cover T9B and the through holes Y2 of the Y-shaped clamp T7 and screwed to the screw holes Y1. At the same time, the Y-shaped clamp T7 and the outer rings of the bearing T4A and the bearing T4B are connected as a whole through the extrusion of the inner ring pressure plate T6A and the inner ring pressure plate T6B. After the arm swing joint is assembled as a whole, the Y-shaped clamp T7 and the T-shaped middle axis T1 can make relative rotational motion around the bearing axis, and the rotation angle of the entire joint can be obtained by detecting the relative angle between the angle sensing code disk T8 and the matching magnetic steel T2 of the first code disk.

[0048] It is worth noting that arm rotation joint 1 M11, arm rotation joint 2 M13 and arm rotation joint 3 M15 have the same structure. Figure 6As shown, the specific components are: main support frame K1, stainless steel round tube K23, code disk fixing ring K7, angle sensor code disk K8, magnetic steel limit bearing K3, stainless steel round tube limit bearing K11, limit card K2, magnetic steel fixing rod K5, second code disk matching magnetic steel K6, rectangular magnet K14, magnet torque transmission sheet K4, toothed metal magnetic strip K13, magnet sliding guide groove K12, wiring card K20 and winding bin K21 and shell K22, wherein the main support frame K1 has two semi-open rings K24, which are fastened by spring screws to control the contraction force of the rings, and the inner surface of the rings is coated with solid stone Ink lubricating powder achieves the effect of linear sliding bearing, so that the stainless steel round tube K23 can slide freely inside and rotate around the axis. The magnetic steel limit bearing K3 is assembled in the end circular groove of the main support frame K1 and clamped by the code disc fixing ring K7. The magnetic steel fixing rod K5 is inserted into the magnetic steel limit bearing K3 and clamped by the retaining spring and the magnetic steel limit bearing K3. There is a groove on the right end of the magnetic steel fixing rod K5. The second code disc supporting magnet K6 is fixed in the groove. The angle sensor code disc K8 is fixed in the code disc fixing ring K7 and is clamped by the T-shaped central axis T1 after assembly. The magnet sliding guide groove K12 is nested in the stainless steel round tube K23. After assembly, it is clamped by the stainless steel round tube K23. The toothed metal magnetic strip K13 is made of spring steel and is a long strip that can be attracted by the rectangular magnet K14. There are serrations on both sides of the long strip. After assembly, the toothed metal magnetic strip K13 is clamped by the magnet sliding guide groove K12. The rectangular magnet K14 is fixed to the magnet torque transmission sheet K4 by screws. The magnet torque transmission sheet K4 is fixed to the magnetic steel fixing rod K5 by screws. The whole system after assembly can realize the seamless transmission of the rotation of the stainless steel round tube K23 to the second code disk supporting magnetic steel K6. The torque transmission order is: stainless steel round tube K23àmagnet sliding Guide groove K12àtoothed metal magnetic strip K13àrectangular magnet K14àmagnet torque transmission sheet K4àmagnet fixing rod K5àsecond code disk supporting magnet K6. When the stainless steel round tube K23 rotates relative to the main support frame K1, the angle sensing code disk K8 can detect the angle of rotation, which is also the rotation angle of the entire joint. The wiring card K20 is fixed on the main support frame K1. There is a groove in the wiring card K20 for electrical wiring and clamping the electrical wiring. The winding bin K21 ensures that the electrical wiring is not exposed and protects the electrical wiring K25 from breaking when the joint rotates. The principle is shown in the cross-sectional view. Figure 8As shown, the electrical wiring K25 is inserted from the tail of the winding bin K21, and after being wound twice in the winding bin K21, it is led out from the gap between the main support frame K1 and the wiring card K20. When the joint rotates, the winding bin K21 and the stainless steel round tube K23 rotate synchronously, and the main support frame K1 and the wiring card K20 rotate synchronously. At this time, because the electrical wiring has been wound loosely twice in the winding bin K21, when the stainless steel round tube K23 and the main support frame K1 have a relative rotation of no more than 360 degrees around the axis, the head and tail of the electrical wiring will follow the safe movement, and the electrical wiring will not be broken as a whole. The outer shell K22 is for protection. After the stainless steel round tube limit bearing K11 is assembled, the inner ring of the bearing and the stainless steel round tube K23 form a whole, and the outer ring of the bearing and the limit The card K2 is formed as a whole. The limit card K2 has screws that can be fixed on the main support frame K1. The contact surfaces of the main support frame K1 and the limit card K2 have multiple equally spaced reserved screw holes along the axial direction of the bearing. By sliding the limit card K2 left and right and fixing it on different reserved screw holes with screws, the depth of the stainless steel round tube K23 inserted into the main support frame K1 can be adjusted, thereby adjusting the arm length of the entire arm rotation joint. The function of adjusting the joint arm length is an optional function. It is only necessary to adjust it when the user's height and arm length differ greatly for ease of use. In the teaching frame M1, only the arm rotation joint M15 is attached to the human arm. When the body shape is not much different, the arm movement can be kept from being blocked by the joint by adjusting the height of the tripod bracket M4.

[0049] It should be noted that the sliding joint M18 is composed of an I-shaped main support frame W11, a threaded optical axis W1 and an optical axis W10, a linear sliding bearing W2 and a linear sliding bearing W9, a spring W3 and a spring W8, an optical axis tail buckle W4 and an optical axis tail buckle W7, a fixed plate W6, and a displacement sensor W5. The tails of the optical axis W1 and the optical axis W10 are fixed by the optical axis tail buckle W4 and the optical axis tail buckle W7. The optical axis W1 and the optical axis W10 pass through the linear sliding bearing W2 and the linear sliding bearing W9 respectively, and can move forward and backward along the axial direction to an appropriate amount. The heads of the optical axis W1 and the optical axis W10 are threaded and fixed to the upper and lower ends of the main housing S1 of the teaching gun M6 respectively. There is a fixing plate W6 on the I-beam main support frame W11, and the threaded holes on it can fix the I-beam main support frame W11 and the arm swing joint M17 as a whole. The displacement sensor W5 is used to detect the sliding amount of the optical axis W1. Through the relatively fixed relationship, it can be known that the detection result of the displacement sensor W5 ultimately represents the movement amount of the teaching gun M6 relative to the arm swing joint M17. During the teaching process, the last arm swing joint M17 of the teaching frame M1 is located on the outside of the human wrist joint and rotates with the wrist, but the two are not coaxial. When the teaching gun M6 is swung outward, the distance between the teaching gun M6 and the human wrist joint is basically fixed, but the distance from the arm swing joint M17 is variable. The installation of the sliding joint can better solve this problem.

[0050] It is worth noting that the overall appearance of the teaching gun M6 Fig.10 As shown, it is mainly composed of a teaching gun main shell S1, an emergency stop trigger S4, a main trigger S5, a force feedback grip back plate S3, a servo motor 1 S21, a servo motor 2 S22, a servo motor 3 S23, a cross universal joint 1 S11, a cross universal joint 2 S12, a cross universal joint 3 S13, a cross universal joint 4 S14, and a retractable rubber guard S6. The emergency stop trigger S4 is used to control the robot arm M2 to stop and start the following movement, and releasing all of them is used to control the robot arm M2 to stop all movements including the electric tool. , Pulling the main trigger S5 to the initial position or above starts the follow-up. The teaching gun M6 is equipped with an angle sensor inside, which can transmit the trigger pull signal to the main controller M5, and control the overall movement and stop of the robot arm M2 through the main controller M5. The main trigger S5 is the trigger for controlling the force of the power tool. During teaching, the angle sensor built into this trigger transmits the angle signal to the main controller M5, which records the control force in real time and sends commands to control the rotation force of the power tool carried by the robot arm M2. Sectional view Fig.11 The internal connection relationship is shown. The teaching gun main shell S1 and the force feedback grip back plate S3 are two physically separated parts, which are elastically connected together by a limit bead S7 with a spring and a limit plate S8 with a spring. The servo motor 1 S21, servo motor 2 S22, servo motor 3 S23 and cross universal joint 1 S11, cross universal joint 2 S12, cross universal joint 3 S13, and cross universal joint 4 S14 together constitute a three-degree-of-freedom force feedback device. The servo motor 1 S21, servo motor 2 S22, and servo motor 3 S23 are all equipped with a reducer and an angle sensor encoder. The main shafts of the servo motor 1 S21 and servo motor 2 S22 are equipped with screws. The cross universal joint 4 S14 and cross universal joint 3 S13 have screw nuts. The servo motor 1 S21 When the main shaft of servo motor 2 S22 rotates, it can drive cross universal joint 4 S14 and cross universal joint 3 S13 to move forward and backward, thereby driving the power feedback grip back plate S3 to move forward and backward. The end of servo motor 3 S23 is provided with cam S9. When the motor rotates, cam S9 can drive the tail of power feedback grip back plate S3 to move forward and backward. During teaching, main controller M5 sends moving position commands to servo motor 1 S21, servo motor 2 S22 and servo motor 3 S23, which can make the force feedback grip back plate S3 achieve appropriate upward, downward, left, right and overall forward and backward movement. The retractable rubber guard plate S6 connects the teaching gun main shell S1 and the force feedback grip back plate S3 from the surface to protect the palm from being clamped due to the forward and backward movement of the back plate during teaching.

[0051] It should be noted that the squeeze sensor M3 Fig.12As shown, it is composed of a spring F2, a displacement sensor F5 embedded in the spring F2, a three-dimensional force sensor F1 including a pressure sensor F8, a pressure sensor F9 and a pressure sensor F10, a fixed plate F3 and a fixed plate F7, a spring cover F6 with a spline shaft and a spring cover F4 with a spline sleeve can generate coaxial relative displacement, and the torque is transmitted by the sleeve connection of the spline shaft and the spline sleeve. When the sensor is squeezed, the displacement sensor F5 can detect the squeezed amount of the spring F4, and convert it into a digital signal and transmit it to the main controller M5 in real time. Fig.13 The internal structure of the three-dimensional force sensor F1 is shown. The pressure sensor F8, the pressure sensor F9 and the pressure sensor F10 together form a 360-degree radial pressure sensor. The sensor housing F11 is a thin-walled housing pressed from an elastic metal material. The contact surface between the housing and the fixed plate F3 can produce a small deformation when squeezed. The pressure sensor F8, the pressure sensor F9 and the pressure sensor F10 sense the squeeze change and convert it into a digital signal in real time and transmit it to the main controller M5. The housing F11 also has The torque of the fixed plate F3 and the spring cover F4 is transmitted to protect the sensor from torque damage. The extrusion sensor M3 is installed as a whole between the end joint flange of the robot arm M2 and the power tool flange. The main controller M5 records the data of the displacement sensor F5, the pressure sensor F8, the pressure sensor F9 and the pressure sensor F10 in real time, and converts them into the rotation amount of the servo motor S21, the servo motor S22 and the servo motor S23, so that the instructor can feel the squeezing of the power tool on the robot arm M2 in real time during the teaching process.

[0052] A method for using an easy-to-use robotic arm teaching system with force feedback comprises the following steps:

[0053] Step 1: Fix the workpiece to be processed firmly in front of the robot arm M2.

[0054] Step 2, install the extrusion sensor M3 between the end flange of the robot arm M2 and the power tool, and connect the sensor signal to the main controller M5. The main controller M5 is connected to the host of the robot arm M2 through a TCP / UDP communication link, so that the main controller M5 can send commands through the communication link to control the robot arm M2 to move and read the coordinates of the end of the power tool.

[0055] Step 3: The touch screen displays arrow keys that can control the movement of the robot arm M2. The instructor clicks the keys to move the end tool of the robot arm M2 to an initial position that is convenient for teaching.

[0056] Step 4: The instructor stands behind the teaching stand, inserts his forearms into the inverted U-hook 1 M19 and the inverted U-hook 2 M20, and holds the teaching gun M6.

[0057] Step 5: The instructor raises his elbow joint to a horizontal position and starts teaching by clicking the “Start Teaching” button on the touch screen.

[0058] Step 6: The instructor slightly pulls the emergency stop trigger S4, and the teaching gun M6 and the robot arm M2 enter the synchronization state. The main controller M5 calculates the coordinates and attitude angle of the teaching gun M6 at this time, and reads the current coordinates and attitude angle of the end of the power tool of the robot arm M2 through the communication link. The offset of the two sets of coordinates is calculated and the coordinates are matched.

[0059] The specific matching process is as follows: the main controller M5 calculates the current coordinates X”Y”Z” and the posture angle A”B”C of the teaching gun M6, and reads the current coordinates X at the end of the power tool of the robot arm M2 through the communication link. D Y D Z D and A D B D C D , calculate the position offset ΔX=X between the two D –X”, ΔY=Y D -Y”, ΔZ=Z D -Z”, ΔA=A D -A”, ΔB=B D -B”, ΔC=C D -C".

[0060] After calculating the position offset, the new coordinates X'Y'Z' and attitude angles A'B'C' of the teaching gun M6 are calculated in real time at a cycle of 10ms or faster. s = X'+ΔX,Y s =Y'+ΔY,Z s =Z' +ΔZ,A s =A' + ΔA, B s =B' + ΔB, C s =C'+ΔC calculate the schematic coordinates X s Y s Z s and A s B s C s When the special protection function of the main controller M5 is not triggered and no special processing is required for the schematic coordinates, the schematic coordinates are equal to the final control coordinates of the robot arm, that is, the control coordinates X k Y k Z k A k B k C k Equal to the schematic coordinate X s Y s Z s A s Bs C s , the main controller M5 sends the control coordinate X k Y k Z k A k B k C k The corresponding control commands control the motion of the robot arm M2.

[0061] At this time, when the instructor moves the teaching gun M6 in various postures, the robot arm M2 will also follow the action.

[0062] Step 7: The instructor observes the effect of the electric tool on the real robot arm M2 on the workpiece, and moves the teaching gun M6 and pulls the main trigger S5 to control the actual action of the robot arm M2 and the electric tool as needed. During the process, the force feedback of the teaching gun M6 and the grip back plate S3 are used to sense the force and direction of the squeeze, adjust the gestures, and teach step by step.

[0063] Step 8, when the teaching is finished, the instructor releases the main trigger S5 and the emergency stop trigger S4, the robot arm M2 and the power tool stop moving, and then ends the teaching by clicking the "End Teaching" button on the touch screen.

[0064] During the teaching process, the main controller M5 reads the real-time coordinates of the end of the power tool of the robot arm M2 and the data of the main trigger S5 through the communication link at a certain time interval, such as once every 5ms, and converts and generates commands that can be executed by the physical robot arm line by line. When the teaching is completed, the command set generated line by line is the final teaching data.

[0065] In addition, during the teaching process, the main controller M5 activates the over-extrusion protection mechanism. Before teaching, the maximum extrusion force and the automatic retraction limit are set through the touch screen. During teaching, when the extrusion force is close to the maximum value, the main controller M5 controls the coordinate X k Y k Z k A k B k C k The backoff value Δ1 is superimposed as the new control coordinate X k2 Y k2 Z k2 A k2 B k2 C k2 , now no longer with X k Y k Z k A k B k C k Generate control commands for the robot arm, but with X k2 Y k2 Z k2A k2 B k2 C k2 Generate the control command of the robot arm for the benchmark. The superposition method is 1) A k2 B k2 C k2 Equal to A k B k C k , 2) Set the coordinate point X k Y k Z k Along A k B k C k The three-dimensional space coordinates are moved in the opposite direction of the linear distance Δ1 to obtain the coordinates of the coordinate point after the movement, and this coordinate is set as X k2 Y k2 Z k2 . The value of Δ1 is a variable value, which is given by the system PID algorithm. The PID algorithm continuously detects the size of the extrusion force and adjusts the value of Δ1 to keep the extrusion force close to but not exceeding the maximum value. At the same time, the main controller M5 emits a buzzer alarm with a proportional frequency according to the size of the backoff value Δ1. When the backoff value Δ1 exceeds the preset automatic backoff limit, the main controller M5 controls the robot arm M2 to stop moving and issues a voice warning to the instructor. When the instructor adjusts the posture of the teaching gun M6 and the backoff value Δ1 returns to the limit again, the main controller M5 controls the robot arm M2 to continue teaching.

[0066] Additionally, during teaching, when the instructor does not click the "End Teaching" button on the touch screen, but only releases the main trigger S5 and the emergency stop trigger S4, the main controller M5 collects the current coordinates of the end of the power tool of the robot arm M2, and issues a command to stop the operation of the robot arm M2 and the power tool. The instructor can freely move the teaching gun M6 to other positions. When the emergency stop trigger S4 is pressed again, the main controller M5 will recalculate the offset values ​​ΔX, ΔY, ΔZ, ΔA, ΔB, ΔC using the method of step 6, and calculate the control coordinates with the new offset values. The teaching gun M6 and the robot arm M2 are synchronized again, and the instructor can continue teaching. The teaching data will be accumulated under the previous data. The instructor can stop and follow again multiple times until the "End Teaching" command on the touch screen is clicked. The entire teaching process is finally ended.

[0067] Additionally, during teaching, under any conditions, when the main controller M5 detects that the squeezing force fed back by the sensor M3 exceeds the set limit value, it unconditionally controls the robot arm M2 and the power tool to stop running for safety protection.

[0068] Optionally, the user can press the "Proportional reduction extrusion depth teaching" button on the touch screen so that after the power tool touches the workpiece, the extrusion depth of the power tool toward the workpiece is not equal to the depth indicated by the teaching gun, but a reduced value of the indicated depth. Before teaching, set the reduction ratio S on the touch screen. uo After this mode is started, when the squeeze sensor M3 detects that the squeeze value is greater than 0, this mode starts. The main controller M5 sets the control coordinate A k B k C k Equal to the schematic coordinates A s B s C s , then for the schematic coordinate X s Y s Z s According to A s B s C s The reverse direction of the move back value J T The distance obtained is the coordinate point as the control coordinate X k Y k Z k Among them, the fallback value J T The calculation steps are as follows: 1) The main controller M5 obtains the actual spatial coordinates X of the electric tool at the end of the current robot arm M2 through the communication link D Y D Z D A D B D C D , and the extrusion length J fed back by the displacement sensor F5 on the extrusion sensor M3 D . 2) The main controller M5 coordinates point X D Y D Z D Along A D B D C D The length of the reverse direction is J D The three-dimensional space coordinates are moved to obtain the new coordinate point X N Y N Z N 3) Calculate the schematic coordinates X of the teaching gun M6 S Y S Z S 4) Calculate X N Y N Z N With X S Y S Z S The straight-line distance between the two N , 5) Calculate the fallback value J T =J N *(1-Suo ).

[0069] Optionally, the existing teaching stand M1 has only one hand, but is not limited to being extended to two hands;

[0070] Optionally, this teaching stand M1 is not limited to use in the industrial robot arm industry, but is also suitable for teaching and direct control in industries such as telemedicine, space operation robots, underwater robot arms, rescue robots, dual-arm robots, robots working in harmful environments such as radiation, virtual reality games, and three-dimensional simulation training.

[0071] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An easy-to-use robotic arm teaching system with force feedback, comprising a teaching frame (M1), a robotic arm (M2) and a squeeze sensor, characterized in that: The teaching stand (M1) comprises a main controller (M5) with a touch screen, a teaching gun (M6), mechanical joints corresponding to human hand joints, and an inverted U hook 1 (M19) and an inverted U hook 2 (M20), wherein the inverted U hook 1 (M19) and the inverted U hook 2 (M20) on the mechanical joints are correspondingly mounted on the forearms of the instructor, and the joint as a whole moves with the arm to sense the movement trajectory of the arm, and the squeeze sensor is correspondingly mounted at the end of the mechanical arm joint; The mechanical joints include arm rotation joint 1 (M11), arm swing joint 1 (M12), arm rotation joint 2 (M13), arm swing joint 2 (M14), arm rotation joint 3 (M15), arm swing joint 3 (M16) and arm swing joint 4 (M17), which correspond to the arm joints of the instructor one by one, and correspond to the shoulder rotation, shoulder swing, upper arm rotation, elbow swing, forearm rotation, wrist vertical swing and wrist outward swing of the arm in sequence; The arm swing joint 1 (M12), arm swing joint 2 (M14) and arm swing joint 3 (M16) and arm swing joint 4 (M17) have the same structure, specifically: outer cover 1 (T9A), first angle sensor code disk (T8), Y-type clamp 1 (T7-L), bearing inner ring pressure plate 1 (T6A), bearing outer ring pressure ring 1 (T5A), bearing 1 (T4A), bearing outer jacket 1 (T3A), first code disk matching magnetic steel (T2), T-type middle shaft (T1), bearing outer jacket 2 (T 3B), bearing 2 (T4B), bearing outer ring pressure ring 2 (T5B), bearing inner ring pressure piece 2 (T6B), Y-type clamp 2 (T7-R) and outer cover 2 (T9B) are connected in sequence. After the overall assembly, Y-type clamp 1 (T7-L), Y-type clamp 2 (T7-R) and T-type center axis (T1) can perform relative rotation around the bearing axis, and the first angle sensor code disc (T8) detects the relative angle with the first code disc matching magnetic steel (T2) to obtain the rotation angle of the entire joint; The arm rotation joint 1 (M11), arm rotation joint 2 (M13) and arm rotation joint 3 (M15) have the same structure, and are specifically composed of: main support frame (K1), stainless steel round tube (K23), code disk fixing ring (K7), second angle sensor code disk (K8), magnetic steel limit bearing (K3), stainless steel round tube limit bearing (K11), limit card (K2), magnetic steel fixing rod (K5), second code disk supporting magnetic steel (K6), rectangular magnet (K14), magnet torque transmission sheet (K4), belt The main support frame (K1) has two semi-open rings (K24), so that the stainless steel tube (K23) can slide freely inside and rotate around the axis. The magnetic steel limit bearing (K3) is assembled in the end groove of the main support frame (K1) and clamped by the code disk fixing ring (K7). The magnetic steel fixing rod (K5) is inserted into the magnetic steel limit bearing (K3). , and is clamped by a retaining spring and a magnetic steel limit bearing (K3). The right end of the magnetic steel fixing rod (K5) has a groove. The second code disk matching magnetic steel (K6) is fixed in the groove. The second angle sensor code disk (K8) is fixed in the code disk fixing ring (K7). After assembly, it is clamped by the T-shaped central axis (T1). The magnet sliding guide groove (K12) is nested in the stainless steel round tube (K23). After assembly, it is clamped by the stainless steel round tube (K23). The wiring clamp (K20) is fixed on the main support frame (K1). The winding bin (K2 1) The electrical wiring is not exposed and the electrical wiring (K25) is protected from being broken when the joint rotates. When the joint rotates, the winding bin (K21) and the stainless steel tube (K23) rotate synchronously, the main support frame (K1) and the wiring clamp (K20) rotate synchronously, and after the stainless steel tube limit bearing (K11) is assembled, the inner ring of the bearing and the stainless steel tube (K23) form a whole, the outer ring of the bearing and the limit clamp (K2) form a whole, and the limit clamp (K2) is fixed on the main support frame (K1); The sliding joint (M18) is composed of an I-shaped main support frame (W11), a threaded optical axis 1 (W1) and an optical axis 2 (W10), a linear sliding bearing 1 (W2) and a linear sliding bearing 2 (W9), a spring 1 (W3) and a spring 2 (W8), an optical axis tail buckle 1 (W4) and an optical axis tail buckle 2 (W7), a fixed plate (W6), and a displacement sensor (W5). The tails of the optical axis 1 (W1) and the optical axis 2 (W10) are fixed by the optical axis tail buckle 1 (W4) and the optical axis tail buckle 2 (W7). Fixed, optical axis one (W1) and optical axis two (W10) pass through linear sliding bearing one (W2) and linear sliding bearing two (W9) respectively, optical axis one (W1) and optical axis two (W10) have threads on their heads, which are fixed on the teaching gun (M6) respectively, and the I-shaped main support frame (W11) is provided with a fixed plate (W6), and the I-shaped main support frame (W11) and arm swing joint four (M17) are fixed as a whole through the threaded holes above, and the displacement sensor (W5) is used to detect the sliding amount of optical axis one (W1).

2. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The touch screen installed on the main controller (M5) displays the teaching trajectory and touch buttons in real time. The main controller (M5) is equipped with a voice recognition system and a built-in speaker.

3. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The first inverted U hook (M19) and the second inverted U hook (M20) are made of flexible metal with a rubber outer layer.

4. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The teaching stand (M1) further comprises a tripod bracket (M4) with adjustable height, and the tripod bracket (M4) is used to support a mechanical joint.

5. The easy-to-use robotic arm teaching system with force feedback according to claim 4, characterized in that: The intersection of the tripod bracket (M4) and the arm rotation joint 1 (M11) is the coordinate origin (M30) of the teaching frame (M1).

6. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The sensor comprises an extrusion sensor (M3) fixed at the end of the working end of the robot arm (M2). The extrusion sensor (M3) can sense the force and direction of the extrusion between the electric tool at the end of the robot arm and the workpiece, and control the three-degree-of-freedom tail plate on the gun handle of the teaching gun to deviate forward, backward, left, right, up and down through the main controller (M5), and feedback the magnitude and direction of the extrusion force to the instructor in real time. When the extrusion sensor detects an abnormal situation, it can control the robot arm (M2) to stop urgently.

7. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The touch screen is provided with a proportional reduction extrusion depth teaching button, and the user starts the proportional reduction extrusion depth teaching mode by touching the button. After this mode is started, when the extrusion sensor (M3) detects that the extrusion value is greater than 0, this mode starts to start, so that the electric tool extrudes the workpiece with proportional reduction.

8. The easy-to-use robotic arm teaching system with force feedback according to claim 1, characterized in that: The teaching system also includes an over-extrusion protection mechanism. During teaching, when the extrusion force approaches the safety limit value, the system can adjust the control coordinates to keep the extrusion force close to but not exceeding the limit value.

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