An industrial robot three-finger gripper and its grasping method

Abstract

The present invention discloses an industrial robot three-finger gripper and its grasping method, which includes a finger structure, a palm structure and a voice coil drive motor; the finger structure consists of three identical mechanical fingers, and the three identical mechanical fingers are respectively separated at 120° at the bottom of the palm structure. The palm structure contains a voice coil drive motor inside. The voice coil drive motor is installed within the palm structure through a fixed base. The lower end of the voice coil drive motor is fixed with a drive disk, which is connected to the finger structure through a long connecting rod; this three-finger clamping manipulator can change the grasping posture through a servo motor. When facing simple objects, it has good envelopability; when facing complex objects, it can formulate a suitable grasping plan according to the shape and direction of the object, and at the same time, relying on the good soft characteristics of the underactuated structure, it realizes the adaptive grasping of the manipulator within a certain range.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and more specifically, to a three-finger gripper for industrial robots and its grasping method. Background Art

[0002] Traditional manipulators have a simple structure and are easy to control, but they can often only be used for specific objects, with poor applicability and unable to meet various requirements. However, for humanoid manipulators, each joint degree of freedom is controlled by a sensor and a drive, which results in high manufacturing costs, great difficulty, a complex structure and being not easy to control. Moreover, this series structure is not applicable to conventional industrial production. To solve the problem between drive and degree of freedom, and at the same time improve the flexibility and versatility of manipulator design, the under-actuated principle is often adopted.

[0003] For example, after retrieval, a patent with the Chinese patent publication number CN 112970428 B, an under-actuated picking manipulator, includes: a robotic arm connection component, a power transmission component, a frame, at least three picking manipulator components and an inter-finger commutation mechanism; wherein, the head end of the frame is fixedly connected with the robotic arm connection frame component, its tail end is connected with the picking manipulator component, and the power transmission component is located between the robotic arm connection frame component and the picking manipulator component. The inter-finger commutation mechanism is arranged on the frame for controlling the rotation of the picking manipulator component; one of the picking manipulator components is a fixed mechanical finger, and the others are rotatable mechanical fingers.

[0004] The above patent has the following deficiencies: it uses a lead screw as the power transmission component. Although the structure is simple and the reliability is strong, the action response is slow and the movement is sluggish.

[0005] Therefore, the present invention proposes a three-finger gripper for industrial robots and its grasping method. Summary of the Invention

[0006] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a three-finger gripper for industrial robots and its grasping method. It has a more reliable, stable and flexible grasping method, with a fast response speed and is suitable for grasping more complex objects.

[0007] The technical solution of the present invention is: a three-finger gripper for industrial robots, including a finger structure, a palm structure and a voice coil drive motor; the finger structure is composed of three identical mechanical fingers, and the three identical mechanical fingers are respectively separated at 120° at the bottom of the palm structure. The palm structure contains a voice coil drive motor inside, and the voice coil drive motor is installed within the palm structure through a fixed base. The lower end of the voice coil drive motor is fixed with a drive disk, which is connected to the upper left drive piece of the finger structure through a long connecting rod.

[0008] Preferably, the finger structure includes three identical robotic fingers. The three robotic fingers are each at 120°, separated under the lower disc of the palm structure, and are fixed to the finger rotation mechanism by long pin shafts. The upper right drive piece is connected to the finger rotation mechanism by an upper pull spring, and the finger rotation mechanism is connected to a servo motor.

[0009] Preferably, for the robotic finger, the middle joint and the proximal joint of the robotic finger are connected by a medium-long pin shaft, and the middle joint and the distal joint of the robotic finger are connected by a lower long pin shaft. The medium-long pin shaft is connected to the left middle drive piece and the right middle drive piece. The lower long pin shaft is connected to the lower right drive piece. The upper left drive piece is connected to the upper end of the upper left connecting rod by a short pin shaft. The left middle drive piece is connected to the lower end of the upper left connecting rod by a short pin shaft. The left middle drive piece is connected to the upper end of the lower left connecting rod by a short pin shaft. The distal joint of the robotic finger is connected to the lower end of the lower left connecting rod by a short pin shaft. The upper right drive piece is connected to the upper end of the upper right connecting rod by a short pin shaft. The right middle drive piece is connected to the lower end of the upper right connecting rod by a short pin shaft. The right middle drive piece is connected to the upper end of the lower right connecting rod by a short pin shaft. The lower right drive piece is connected to the lower end of the lower right connecting rod by a short pin shaft. The back of the distal joint of the robotic finger is connected to the lower right connecting rod by a lower pull spring. The long pin shaft is fixed to the pin shaft sleeve through a hole. The short pin shaft is fixed to the pin shaft sleeve through a hole. The medium-long pin shaft is fixed to the pin shaft sleeve through a hole. The lower long pin shaft is fixed to the pin shaft sleeve through a hole.

[0010] Preferably, the palm structure includes a servo motor, a first column, a finger rotation mechanism, an upper disc of the palm structure, and a lower disc of the palm structure. The three servo motors are each fixed at 120° above the lower disc of the palm structure. The lower disc of the palm structure is connected to the upper disc of the palm structure by three first columns. The finger rotation mechanism is connected to the servo motor. A voice coil driving motor is installed inside the palm structure.

[0011] Preferably, the structure of the voice coil driving motor mainly includes: an armature sleeve wound with coils is connected to a driving disc to form a mover of the voice coil driving motor, and a permanent magnet is installed on a fixed base to form a stator of the voice coil driving motor.

[0012] Preferably, the long pull spring of the voice coil driving motor is connected between the fixed base and the bottom of the armature sleeve. A grating scale is installed on the side of the armature sleeve, and a reading head is fixed at a corresponding position. The armature sleeve is installed on a linear slide rail. The overall structure of the voice coil driving motor makes a linear reciprocating motion through the linear slide rail. After being energized, the armature sleeve with the wound copper coil makes a reciprocating linear motion under the action of the electromagnetic field. The displacement signal of the armature sleeve is measured by the grating scale and the reading head and converted into a digital signal for output.

[0013] Preferably, the voice coil driving motor is mounted under the upper disc of the palm structure through a fixed base. A permanent magnet is fixed under the fixed base. Two long tension springs are connected between the armature sleeve and the fixed base. The armature sleeve moves on a linear slide rail. A driving disc is fixed under the armature sleeve. The driving disc is triangular in shape. The tip of the triangle is connected to a movable link. The end of the movable link is connected to a long link. The end of the long link is connected to the upper left driving piece of the finger structure.

[0014] Preferably, the linear slide rail is fixed on a slide rail fixing platform. The upper end of the slide rail fixing platform is connected to the upper disc of the palm structure. The lower end of the slide rail fixing platform is connected to the lower disc of the palm structure. A reading head is installed on the slide rail fixing platform. A grating scale is installed on the side of the armature sleeve.

[0015] Preferably, the driving disc is restricted by a second column and the slide rail fixing platform and can only move in the vertical direction. By applying a force at the position of the driving disc, the finger structure is driven to rotate. The movable link is connected to the long link and the driving disc, and the movable link rotates horizontally at a certain angle on the driving disc. The proximal phalanx of the mechanical finger is connected to the finger rotating mechanism, and the finger rotating mechanism is connected to the end of the servo motor.

[0016] Preferably, a method for the three-finger gripper of an industrial robot to grasp an object is realized, including the following steps:

[0017] (1) When the voice coil driving motor is powered on and operates, a magnetic field is generated when the coil on the armature sleeve is energized. When the magnetic field generated by the energized coil on the armature sleeve is in the same direction as the magnetic field of the permanent magnet, the armature sleeve moves towards the permanent magnet. When the magnetic field generated by the energized coil on the armature sleeve is in the opposite direction to the magnetic field of the permanent magnet, the armature sleeve moves away from the permanent magnet.

[0018] (2) When the magnetic field generated by the energized coil on the armature sleeve is in the opposite direction to the magnetic field of the permanent magnet, the armature sleeve moves away from the permanent magnet. At the same time, the two long tension springs connected between the armature sleeve and the fixed base are stretched, pulling the armature sleeve.

[0019] (3) When the armature sleeve moves away from the permanent magnet, the armature sleeve pushes the driving disc. The movable link connected to the driving disc pushes the long link, and the long link moves downward. Since the upper end of the proximal phalanx of the mechanical finger is connected to the finger rotating mechanism through a long pin shaft, the long link pushes the upper left driving piece to make the finger close inward.

[0020] (4) The long link pushes the upper left driving piece to make the finger close inward. The force applied to the upper left driving piece pushes the upper left link. The upper left link pushes the middle left driving piece. The middle left driving piece pushes the lower left link. The lower left link pushes the distal phalanx of the mechanical finger to close until an object is grasped.

[0021] (5) When the magnetic field generated by the energized coil on the armature sleeve is in the same direction as the magnetic field of the permanent magnet, under the action of the long pull spring and the magnetic force, the armature sleeve moves towards the permanent magnet. The armature sleeve drives the drive disk, the drive disk drives the movable link and the long link, and the long link moves upward to pull the finger structure outward to stretch, completing the action of releasing the object;

[0022] (6) The grating ruler and the reading head convert the detected displacement data into digital signals and send them to the processor for processing;

[0023] (7) When grasping a complex object, the servo motor rotates to drive the mechanical finger, and rotates to the corresponding position before performing the grasping action.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The present invention selects the voice coil linear motor as the main structure of the drive system, making the overall structure simple, small in size, high in precision, and high in frequency response.

[0026] (2) The present invention is suitable for grasping more types of objects. The palm mechanism is designed as a circle, and a rotating mechanism is installed at the end of each finger. Controlled by the servo motor, its function can facilitate the replacement of the finger mechanism and also realize various different grasping methods of underactuated fingers.

[0027] (3) The present invention directly controls the rotation of the finger structure through the servo motor, with small power loss. The three servo motors are each placed at 120°, and each controls a mechanical finger. The finger structure has various postures and is more suitable for grasping complex objects.

[0028] (4) The present invention adopts an underactuated three-finger clamping structure. The finger structure is simple and mainly includes three modules: the finger mechanism, the palm mechanism, and the voice coil drive motor. Except for the voice coil drive motor, each part can be printed and assembled by a 3D printer, with low usage cost. Description of the Drawings

[0029] Figure 1 is a schematic diagram of the overall mechanical hand structure of the three-finger gripper of the industrial robot of the present invention.

[0030] Figure 2 is a schematic diagram of the finger structure of the three-finger gripper of the industrial robot of the present invention.

[0031] Figure 3 is a three-dimensional schematic diagram of the finger structure of the three-finger gripper of the industrial robot of the present invention.

[0032] Figure 4 is a schematic diagram of the palm structure of the three-finger gripper of the industrial robot of the present invention.

[0033] Figure 5It is a schematic diagram of the overall structure of the voice coil drive motor of the three-finger gripper of the industrial robot of the present invention.

[0034] Figure 6 It is a schematic diagram of the partial structure of the voice coil drive motor of the three-finger gripper of the industrial robot of the present invention.

[0035] Figure 7 It is a schematic diagram of the grasping of the three-finger gripper of the industrial robot of the present invention.

[0036] In the figure: 1 - finger structure; 2 - palm structure; 3 - voice coil drive motor; 4 - long connecting rod; 5 - upper pull spring; 1000 - mechanical finger; 1001 - end joint of mechanical finger; 1002 - middle joint of mechanical finger; 1003 - proximal joint of mechanical finger; 1004 - lower pull spring; 1005 - upper left connecting rod; 1006 - upper right connecting rod; 1007 - lower left connecting rod; 1008 - lower right connecting rod; 1009 - upper left drive plate; 1010 - upper right drive plate; 1011 - middle left drive plate; 1012 - middle right drive plate; 1013 - lower right drive plate; 1014 - long pin shaft; 1015 - short pin shaft; 1016 - lower long pin shaft; 1017 - middle long pin shaft; 1018 - pin shaft sleeve; 2001 - upper disc of palm structure; 2002 - first column; 2003 - steering gear; 2004 - lower disc of palm structure; 2005 - finger rotation mechanism; 3001 - reading head; 3002 - grating scale; 3003 - armature sleeve; 3004 - long pull spring; 3005 - fixed base; 3006 - permanent magnet; 3007 - movable connecting rod; 3008 - drive disc; 3009 - second column; 3010 - linear slide rail; 3011 - slide rail fixing platform. Specific embodiments

[0037] Please refer to Figure 1-7, the present invention provides a technical solution: an industrial robot three-finger gripper and its grasping method, including finger structure 1, palm structure 2, voice coil drive motor 3, long connecting rod 4, upper pull spring 5, mechanical finger 1000, mechanical finger end joint 1001, mechanical finger middle joint 1002, mechanical finger proximal joint 1003, lower pull spring 1004, upper left connecting rod 1005, upper right connecting rod 1006, lower left connecting rod 1007, lower right connecting rod 1008, upper left drive piece 1009, upper right drive piece 1010, left middle drive piece 1011, right middle drive piece 1012, lower right drive piece 1013, long pin shaft 1014, short pin shaft 1015, lower long pin shaft 1016, middle long pin shaft 1017, pin shaft sleeve 1018, upper disk of palm structure 2001, first column 2002, servo motor 2003, lower disk of palm structure 2004, finger rotation mechanism 2005, reading head 3001, grating scale 3002, armature sleeve 3003, long pull spring 3004, fixed base 3005, permanent magnet 3006, movable connecting rod 3007, drive disk 3008, second column 3009, linear slide rail 3010, slide rail fixing platform 3011.

[0038] The finger structure 1 is composed of three identical mechanical fingers 1000. The three identical mechanical fingers 1000 are respectively separated at 120° at the bottom of the palm structure 2. The inside of the palm structure 2 contains a voice coil drive motor 3. The voice coil drive motor 3 is installed inside the palm structure 2 through a fixed base 3005. The lower end of the voice coil drive motor 3 is fixed with a drive disk 3008, which is connected to the upper left drive piece 1009 of the finger structure 1 through a long connecting rod 4.

[0039] The finger structure 1 includes three identical mechanical fingers 1000. The three mechanical fingers 1000 are respectively separated at 120° under the lower disk 2004 of the palm structure. They are fixed on the finger rotation mechanism 2005 through a long pin shaft 1014. The upper right drive piece 1010 is connected to the finger rotation mechanism 2005 through an upper pull spring 5. The finger rotation mechanism 2005 is connected to the servo motor 2003.

[0040] The mechanical finger 1000 has its middle finger segment 1002 and proximal finger segment 1003 connected by a middle long pin shaft 1017, and its middle finger segment 1002 and distal finger segment 1001 connected by a lower long pin shaft 1016. The middle long pin shaft 1017 is connected to the left middle driving piece 1011 and the right middle driving piece 1012. The lower long pin shaft 1016 is connected to the lower right driving piece 1013. The upper left driving piece 1009 is connected to the upper end of the upper left connecting rod 1005 through a short pin shaft 1015. The left middle driving piece 1011 is connected to the lower end of the upper left connecting rod 1005 through a short pin shaft 1015, and is also connected to the upper end of the lower left connecting rod 1007 through a short pin shaft 1015. The distal finger segment 1001 is connected to the lower end of the lower left connecting rod 1007 through a short pin shaft 1015. The upper right driving piece 1010 is connected to the upper end of the upper right connecting rod 1006 through a short pin shaft 1015. The right middle driving piece 1012 is connected to the lower end of the upper right connecting rod 1006 through a short pin shaft 1015, and is also connected to the upper end of the lower right connecting rod 1008 through a short pin shaft 1015. The lower right driving piece 1013 is connected to the lower end of the lower right connecting rod 1008 through a short pin shaft 1015. The back of the distal finger segment 1001 is connected to the lower right connecting rod 1008 through a pull-down spring 1004. The long pin shaft 1014 is fixed to the pin shaft sleeve 1018 through a hole, the short pin shaft 1015 is fixed to the pin shaft sleeve 1018 through a hole, the middle long pin shaft 1017 is fixed to the pin shaft sleeve 1018 through a hole, and the lower long pin shaft 1016 is fixed to the pin shaft sleeve 1018 through a hole.

[0041] The palm structure 2 includes a servo motor 2003, a first column 2002, a finger rotation mechanism 2005, an upper palm structure disc 2001 and a lower palm structure disc 2004. Three servo motors 2003 are respectively fixed on the lower palm structure disc 2004 at 120°. The lower palm structure disc 2004 is connected to the upper palm structure disc 2001 through three first columns 2002. The finger rotation mechanism 2005 is connected to the servo motor 2003. A voice coil driving motor 3 is installed inside the palm structure 2.

[0042] The structure of the voice coil driving motor 3 includes an armature sleeve 3003 wound with coils, which is connected to a driving disc 3008 to form the mover of the voice coil driving motor 3, and a permanent magnet 3006 installed on a fixed base 3005 to form the stator of the voice coil driving motor 3.

[0043] The long pull spring 3004 of the voice coil drive motor 3 is connected to the fixed base 3005 and the bottom position of the armature sleeve 3003. A grating scale 3002 is installed on the side of the armature sleeve 3003, and a reading head 3001 is fixed at the corresponding position. The armature sleeve 3003 is installed on the linear slide rail 3010. The overall structure of the voice coil drive motor 3 makes a linear reciprocating motion through the linear slide rail 3010. After being energized, the armature sleeve 3003 of the wound copper coil makes a reciprocating linear motion through the linear slide rail 3010 under the action of the electromagnetic field. The displacement signal of the armature sleeve 3003 is measured by the grating scale 3002 and the reading head 3001 and converted into a digital signal for output.

[0044] The voice coil drive motor 3 is loaded under the upper disc 2001 of the palm structure through the fixed base 3005. A permanent magnet 3006 is fixed under the fixed base 3005. The armature sleeve 3003 and the fixed base 3005 are connected by two long pull springs 3004. The armature sleeve 3003 moves on the linear slide rail 3010. A drive disc 3008 is fixed under the armature sleeve 3003. The drive disc 3008 is triangular in shape, and the tip of the triangle is connected to the movable connecting rod 3007. The end of the movable connecting rod 3007 is connected to the long connecting rod 4, and the end of the long connecting rod 4 is connected to the upper left drive piece 1009 of the finger structure 1.

[0045] The linear slide rail 3010 is fixed on the slide rail fixing platform 3011. The upper end of the slide rail fixing platform 3011 is connected to the upper disc 2001 of the palm structure, and the lower end of the slide rail fixing platform 3011 is connected to the lower disc 2004 of the palm structure. The reading head 3001 is installed on the slide rail fixing platform 3011, and the grating scale 3002 is installed on the side of the armature sleeve 3003.

[0046] The drive disc 3008 is restricted by the second column 3009 and the slide rail fixing platform 3011 and can only move in the vertical direction. By applying a force at the position of the drive disc 3008, the finger structure 1 is driven to rotate. Among them, the movable connecting rod 3007 is connected to the long connecting rod 4, and the movable connecting rod 3007 is connected to the drive disc 3008, and the movable connecting rod 3007 rotates horizontally at a certain angle on the drive disc 3008. The proximal phalanx 1003 of the mechanical finger is connected to the finger rotation mechanism 2005, and the finger rotation mechanism 2005 is connected to the end of the servo motor 2003.

[0047] Due to the use of the underactuated finger structure 1, when clamping an object, it has a certain range of adaptability. For example: when clamping an object with a height only the size of the distal phalanx 1001 of the mechanical finger, the manipulator will adapt to pinch; when clamping an object with a height larger than the distal phalanx 1001 of the mechanical finger, the manipulator will adapt to envelope grasping.

[0048] Adopt a voice coil drive motor 3 structure to drive the finger structure. Add a finger rotation mechanism 2005 to the end position of each mechanical finger 1000 and connect it to the end of the servo 2003. Control the finger rotation angle through the servo 2003. Refer to Figure 7 Change the grasping posture through the servo 2003, such as three-finger centering grasping, three-finger opposing grasping, two-finger grasping and other modes.

[0049] After being powered on, the armature sleeve 3003 of the wound copper coil moves in a reciprocating linear motion through the linear slide rail 3010 under the action of the electromagnetic field. Measure the displacement signal of the armature sleeve 3001 through the grating scale 3002 and the reading head 3001 and convert it into a digital signal for output. After signal processing by the control chip, the grasping force of the manipulator is monitored and measured in real time. The grating scale 3002 converts the detected displacement data into a digital signal and sends it to the processor for processing. At the same time, the grating scale 3002 can also measure the displacement magnitude within a unit period, and the running speed of the voice coil drive motor 3 can be obtained.

[0050] The grating scale 3002 and the reading head 3001 measure linear displacement or angular displacement based on the formation principle of Moiré fringes, that is, realize data measurement through the diffraction effect of the grating, convert the detected displacement data into a digital signal, and send it to the processor for processing.

[0051] When two-finger grasping, by default, the servos 2003 are each installed at 120° on the lower disc 2004 of the palm structure. When two-finger grasping, two of the servos 2003 rotate to opposite positions, and the rotation of the servos 2003 drives the mechanical fingers 1000, and then the grasping action is performed.

[0052] Implement a three-finger gripper grasping method for industrial robots, including the following steps:

[0053] (1) When the voice coil drive motor 3 is powered on and operates, the coil on the armature sleeve 3003 is energized to generate a magnetic field. When the magnetic field generated by the coil on the armature sleeve 3003 is in the same direction as the magnetic field of the permanent magnet 3006, the armature sleeve 3003 moves towards the direction close to the permanent magnet 3006. When the magnetic field generated by the coil on the armature sleeve 3003 is in the opposite direction to the magnetic field of the permanent magnet 3006, the armature sleeve 3003 moves towards the direction away from the permanent magnet 3006;

[0054] (2) When the magnetic field generated by the coil on the armature sleeve 3003 is in the opposite direction to the magnetic field of the permanent magnet 3006, the armature sleeve 3003 moves towards the direction away from the permanent magnet 3006. At the same time, the two long tension springs 3004 connected between the armature sleeve 3003 and the fixed base 3005 are stretched, pulling the armature sleeve 3003;

[0055] (3)When the armature sleeve 3003 moves away from the permanent magnet 3006, the armature sleeve 3003 pushes the drive disk 3008, and the movable connecting rod 3007 connected to the drive disk 3008 pushes the long connecting rod 4. The long connecting rod 4 moves downward. Since the upper end of the proximal phalanx 1003 of the mechanical finger is connected to the finger rotating mechanism 2005 through the long pin shaft 1014, the long connecting rod 4 pushes the upper left drive piece 1009 to make the fingers close inward;

[0056] (4)The long connecting rod 4 pushes the upper left drive piece 1009 to make the fingers close inward. The force applied to the upper left drive piece 1009 pushes the upper left connecting rod 1005. The upper left connecting rod 1005 pushes the middle left drive piece 1011. The middle left drive piece 1011 pushes the lower left connecting rod 1007. The lower left connecting rod 1007 pushes the distal phalanx 1001 of the mechanical finger to close until an object is grasped;

[0057] (5)When the magnetic field generated by the energized coil in the armature sleeve 3003 is in the same direction as the magnetic field of the permanent magnet 3006, under the action of the long tension spring 3004 and the magnetic force, the armature sleeve 3003 moves toward the permanent magnet 3006. The armature sleeve 3003 drives the drive disk 3008. The drive disk 3008 drives the movable connecting rod 3007 and the long connecting rod 4. The long connecting rod 4 moves upward to pull the finger structure 1 outward to complete the action of releasing the object;

[0058] (6)The grating scale 3002 and the reading head 3001 convert the detected displacement data into digital signals and send them to the processor for processing;

[0059] (7)When grasping a complex object, the servo motor 2003 rotates to drive the mechanical finger 1000, rotates to the corresponding position and then performs the grasping action.

Claims

1. An industrial robot three-finger gripper, characterized in that, The three-finger gripper of the industrial robot includes a finger structure (1), a palm structure (2), and a voice coil drive motor (3); The finger structure (1) includes three identical mechanical fingers (1000). The three mechanical fingers (1000) are respectively separated at 120° at the bottom of the palm structure (2). The inside of the palm structure (2) contains a voice coil drive motor (3). The voice coil drive motor (3) is installed inside the palm structure (2) through a fixed base (3005). The lower end of the voice coil drive motor (3) is fixed with a drive disk (3008), which is connected to the upper left drive piece (1009) of the finger structure (1) through a long connecting rod (4); The structure of the voice coil drive motor (3) includes an armature sleeve (3003) wound with coils, which is connected to the drive disk (3008) to form the mover of the voice coil drive motor (3), and a permanent magnet (3006) is installed on the fixed base (3005) to form the stator of the voice coil drive motor (3); The long pull spring (3004) of the voice coil drive motor (3) is connected to the bottom position of the fixed base (3005) and the armature sleeve (3003). A grating scale (3002) is installed on the side of the armature sleeve (3003), and a reading head (3001) is fixed at the corresponding position. The armature sleeve (3003) is installed on a linear slide rail (3010). The overall structure of the voice coil drive motor (3) makes a linear reciprocating motion through the linear slide rail (3010). After being energized, the armature sleeve (3003) of the wound copper coil makes a reciprocating linear motion through the linear slide rail (3010) under the action of the electromagnetic field. The displacement signal of the armature sleeve (3003) is measured by the grating scale (3002) and the reading head (3001) and converted into a digital signal for output; The voice coil drive motor (3) is loaded under the upper disk (2001) of the palm structure through a fixed base (3005). A permanent magnet (3006) is fixed under the fixed base (3005). The armature sleeve (3003) and the fixed base (3005) are connected by two long pull springs (3004). The armature sleeve (3003) moves on the linear slide rail (3010). The drive disk (3008) is fixed under the armature sleeve (3003). The drive disk (3008) is triangular in shape, and the tip of the triangle is connected to a movable connecting rod (3007). The end of the movable connecting rod (3007) is connected to the long connecting rod (4), and the end of the long connecting rod (4) is connected to the upper left drive piece (1009) of the finger structure (1); The driving disk (3008) is constrained by the second column (3009) and the slide rail fixing platform (3011), and can only move in the vertical direction. By applying a force at the position of the driving disk (3008), the finger structure (1) is driven to move. Among them, the movable connecting rod (3007) is connected to the long connecting rod (4), the movable connecting rod (3007) is connected to the driving disk (3008), and the movable connecting rod (3007) rotates horizontally at a certain angle on the driving disk (3008). The upper end of the proximal phalanx (1003) of the mechanical finger is connected to the finger rotating mechanism (2005), and the finger rotating mechanism (2005) is connected to the end of the servo motor (2003).

2. The three-finger gripper of the industrial robot according to claim 1, characterized in that: The three mechanical fingers (1000) are separated under the lower disk (2004) of the palm structure and are fixed to the finger rotating mechanism (2005) through the long pin shafts (1014). The upper right driving piece (1010) is connected to the finger rotating mechanism (2005) through the upper pulling spring (5), and the finger rotating mechanism (2005) is connected to the servo motor (2003).

3. The three-finger gripper of the industrial robot according to claim 2, characterized in that: For the mechanical finger (1000), the middle phalanx (1002) and the proximal phalanx (1003) of the mechanical finger are connected through the middle long pin shaft (1017), the middle phalanx (1002) and the distal phalanx (1001) of the mechanical finger are connected through the lower long pin shaft (1016). The middle long pin shaft (1017) is connected to the left middle driving piece (1011), the middle long pin shaft (1017) is connected to the right middle driving piece (1012), the lower long pin shaft (1016) is connected to the lower right driving piece (1013). The upper left driving piece (1009) is connected to the upper end of the upper left connecting rod (1005) through the short pin shaft (1015), the left middle driving piece (1011) is connected to the lower end of the upper left connecting rod (1005) through the short pin shaft (1015), the left middle driving piece (1011) is connected to the upper end of the lower left connecting rod (1007) through the short pin shaft (1015), the distal phalanx (1001) of the mechanical finger is connected to the lower end of the lower left connecting rod (1007) through the short pin shaft (1015). The upper right driving piece (1010) is connected to the upper end of the upper right connecting rod (1006) through the short pin shaft (1015), the right middle driving piece (1012) is connected to the lower end of the upper right connecting rod (1006) through the short pin shaft (1015), the right middle driving piece (1012) is connected to the upper end of the lower right connecting rod (1008) through the short pin shaft (1015), the lower right driving piece (1013) is connected to the lower end of the lower right connecting rod (1008) through the short pin shaft (1015). The back of the distal phalanx (1001) of the mechanical finger is connected to the lower right connecting rod (1008) through the lower pulling spring (1004). The long pin shaft (1014) is fixed to the pin shaft sleeve (1018) through the hole, the short pin shaft (1015) is fixed to the pin shaft sleeve (1018) through the hole, the middle long pin shaft (1017) is fixed to the pin shaft sleeve (1018) through the hole, and the lower long pin shaft (1016) is fixed to the pin shaft sleeve (1018) through the hole.

4. The three-finger gripper of the industrial robot according to claim 1, wherein: The palm structure (2) includes a servo motor (2003), a first column (2002), a finger rotation mechanism (2005), an upper disk (2001) of the palm structure, and a lower disk (2004) of the palm structure. Three servo motors (2003) are respectively fixed on the lower disk (2004) of the palm structure at 120°. The lower disk (2004) of the palm structure is connected to the upper disk (2001) of the palm structure through three first columns (2002). The finger rotation mechanism (2005) is connected to the servo motor (2003). A voice coil drive motor (3) is installed inside the palm structure (2).

5. The three-finger gripper of an industrial robot according to claim 1, wherein: The linear slide rail (3010) is fixed on a slide rail fixing platform (3011). The upper end of the slide rail fixing platform (3011) is connected to the upper disk (2001) of the palm structure, and the lower end of the slide rail fixing platform (3011) is connected to the lower disk (2004) of the palm structure. A reading head (3001) is installed on the slide rail fixing platform (3011).

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