Multi-degree-of-freedom co-driven humanoid five-finger dexterous hand and control method

Abstract

The invention belongs to the technical field of robots, and discloses a multi-degree-of-freedom co-driven humanoid five-finger dexterous hand and a control method, the multi-degree-of-freedom co-driven humanoid five-finger dexterous hand comprises a palm back plate, a palm front panel and five fingers, the five fingers adopt modular design and have completely same structures, each finger has three active degrees of freedom and one passive degree of freedom, and each active degree of freedom and the corresponding passive degree of freedom are in parallel. Wherein three active degrees of freedom are respectively a base joint bending degree of freedom, a base joint side-sway degree of freedom and a middle joint bending degree of freedom and are cooperatively controlled by three servo motors at the bottom of the finger, and one passive degree of freedom is a far joint bending degree of freedom and is realized by a planetary gear train under-actuated mechanism in the finger. A space wheel train mechanism is introduced, the humanoid five-finger dexterous hand is designed, mutual coupling control over the three active freedom degrees of base joint bending, base joint side swing and middle joint bending is achieved, each active freedom degree is cooperatively controlled by three motors, the finger space is simplified, and the output force is increased.

Description

Technical Field

[0001] The present invention belongs to the field of robotics technology, and in particular relates to a multi-degree-of-freedom co-driven human five-finger dexterous hand and a control method thereof. Background Art

[0002] Robots need end effectors with sufficient degrees of freedom to perform tasks set by humans. In the world we live in, most tools and their application scenarios are designed according to human physiological structure and operating habits. Therefore, imitating the physiological structure and operating functions of human hands has become an important choice for designing robot end effectors.

[0003] Some current robotic five-fingered hands are designed with four or five fingers as a whole, which makes the structural design simpler and more flexible. However, when a problem occurs in one of the finger components, the entire structure needs to be dismantled, greatly increasing the cost of maintenance. During the manufacturing process, the cost of the manufacturing process will also increase due to the complexity of the overall process.

[0004] To mimic the human hand, a five-fingered robotic hand typically needs to construct three active degrees of freedom: bending of the base joint, lateral swing, and bending of the medial joint. A passive coupling drive method is generally used for the distal joints. Some designs employ three separate actuators for the three active degrees of freedom, which simplifies the structural design but makes the overall structure of the finger very bulky. One degree of freedom needs to be attached to another complete degree of freedom structure, which further restricts the already narrow overall design space, making it difficult to complete the design task within the limited size range. It is also not conducive to the subsequent addition of components such as sensors inside the fingers, making the overall five-fingered dexterous hand very bulky.

[0005] In terms of degree of freedom design, some adopt a scheme that couples the bending and lateral freedom of the base joint, such as a differential mechanism structure or a spatial link structure. This design couples the two degrees of freedom and increases the fingertip force, but the degree of freedom of the middle joint is still driven separately, which will also make the overall size of the finger larger.

[0006] Therefore, there is a need for a dexterous hand that can couple the three degrees of freedom of finger base joint bending, side swing and middle joint bending. This can greatly improve the fingertip force of the robot finger and also simplify the finger structure space of the dexterous hand. Summary of the Invention

[0007] The purpose of the present invention is to provide a multi-degree-of-freedom co-driven human-like five-finger dexterous hand to solve the technical problems of large structural size and low output force in existing robot five-finger dexterous hands.

[0008] To solve the above technical problems, the specific technical solutions of the multi-degree-of-freedom co-driven human five-finger dexterous hand and control method of the present invention are as follows: The invention discloses a multi-degree-of-freedom co-driven humanoid five-finger dexterous hand, comprising a palm back plate, a palm front plate and five fingers. The five fingers include a thumb, index finger, middle finger, ring finger and pinky finger. The index finger, middle finger, ring finger and pinky finger are fixedly connected to the palm back plate. The four fingers are staggered at different heights. The thumb lies horizontally in the gap below the middle finger and ring finger and is fixedly connected to the palm back plate. Finally, the palm front plate is covered to form a complete humanoid five-finger dexterous hand. The five fingers have a total of 20 degrees of freedom, 15 of which are active degrees of freedom and 5 are passive degrees of freedom. The five fingers adopt a modular design and have exactly the same structure. Each finger has 3 active degrees of freedom and 1 passive degree of freedom. The 3 active degrees of freedom are base joint bending degree of freedom, base joint lateral swing degree of freedom and middle joint bending degree of freedom, which are collaboratively controlled by three servo motors at the bottom of the finger. The 1 passive degree of freedom is distal joint bending degree of freedom, which is realized by a planetary gear under-driven mechanism inside the finger.

[0009] Furthermore, the base joint bending degree of freedom and base joint lateral swing degree of freedom structure of a single finger include a motor fixing frame, three servo motors, a motor shaft bevel gear, a transmission bevel gear, a motor fixing frame small plate, a lateral swing shaft and a bending shaft. The motor fixing frame is fixedly mounted on the back panel of the palm, the three servo motors are fixedly mounted on the motor fixing frame, the end of the motor shaft is fixedly connected to the motor shaft bevel gear, the motor shaft bevel gear is meshed with the respective transmission bevel gears, and the finger movement is controlled by the transmission bevel gear. The motor fixing frame small plate is fixedly mounted on the far end of the motor fixing frame, and a bearing hole is each opened at the inner end of the motor fixing frame and the motor fixing frame small plate. Bearings are respectively placed on both ends of the lateral swing shaft and placed in the bearing holes. A hole is dug in the middle of the lateral swing shaft, and the bending shaft passes through it and is fixed, so that the two shafts are fixedly connected as one to form a cross rod. The movement of the base joint is based on this cross rod.

[0010] Furthermore, the three servo motors are, from left to right, the first drive motor, the second drive motor, and the third drive motor, and the corresponding motor shaft bevel gears are the first motor shaft bevel gear, the second motor shaft bevel gear, and the third motor shaft gear, and the matching transmission bevel gears are the first duplex gear, the second duplex gear, and the third duplex gear. Each degree of freedom of movement is controlled by the three motors.

[0011] Furthermore, the end of the motor shaft of the first drive motor is fixedly connected to the first motor shaft bevel gear with a flange and locked with a top screw on the first motor shaft bevel gear, and the first motor shaft bevel gear is then engaged with the first duplex gear; the first duplex gear is composed of two bevel gears of the same specification installed back to back, and the end faces of the two bevel gears are fixedly connected together to form a duplex gear.

[0012] Furthermore, the end of the motor shaft of the second drive motor is fixedly connected to the second motor shaft bevel gear, and the second motor shaft bevel gear is meshed with the second duplex gear. The second duplex gear is composed of two large and small bevel gears. The flange shaft of the small gear passes through the hole of the large gear and is fixedly connected together to form a duplex gear.

[0013] Furthermore, the end of the motor shaft of the third drive motor is fixedly connected to the third motor shaft gear, and the third motor shaft gear is meshed with the third duplex gear. The third duplex gear is composed of a cylindrical gear and a bevel gear. The end face of the cylindrical gear and the end face of the bevel gear are fixedly connected together to form a duplex gear, which is mounted on the shaft of the second drive motor through a rolling bearing. The third duplex gear is meshed with the third bevel gear, and the third bevel gear is mounted on the side swing shaft through a rolling bearing. The third bevel gear is then meshed with the third single output bevel gear on the left.

[0014] Furthermore, the finger realizes base joint bending and lateral swing through a base joint differential mechanism. The base joint differential mechanism includes a first duplex gear, a second duplex gear, an output bevel gear, a third bevel gear and a third single output bevel gear. The output bevel gear is sleeved on the bending shaft, and the other end of the bending shaft passes through the third single output bevel gear.

[0015] Furthermore, the middle joint bending freedom structure includes a third single output bevel gear, an output bevel gear, a planetary carrier, a middle joint shaft, a left cylindrical gear and a right side plate. The planetary carrier is a bent connecting rod, one end of which is sleeved on the bent shaft of the base joint through a rolling bearing, and the other end is sleeved on the middle joint shaft through a rolling bearing. The left side of the middle joint shaft is bonded and fixed to the left cylindrical gear, and the left cylindrical gear is meshed with the small half internal gear at the upper end of the third single output bevel gear. The right side of the middle joint shaft is fixed to the right side plate, and the right side plate is fixed to the output The small half of the external gear at the upper end of the output bevel gear is meshed. When the small half of the external gear at the upper end of the rightmost output bevel gear and the small half of the internal gear at the upper end of the third single-fold output bevel gear on the left rotate in the same direction, the planetary gear revolves. At this time, the proximal knuckle and the middle knuckle rotate together around the bending axis of the base joint as a rigid whole; when the small half of the external gear at the upper end of the rightmost output bevel gear and the small half of the internal gear at the third single-fold output bevel gear on the left rotate in opposite directions, the planetary carrier remains stationary and the planetary gear rotates on its own. At this time, the proximal knuckle remains stationary, and the middle knuckle bends around the middle knuckle axis.

[0016] Furthermore, the distal joint bending freedom includes a left side plate, four gears and a fingertip. The four gears include a first gear, a second gear, a third gear and a fourth gear. The four gears are meshed in sequence. The first gear is fixed on the planetary frame of the middle joint, which can be regarded as a fixed frame in this mechanism. The second gear and the third gear are fixed on the left side plate through bearings. The left side plate serves as the planetary frame of the distal finger joint planetary gear system. The lower end of the left side plate is fixedly connected to the middle joint shaft, and the top fourth gear is integrated with the fingertip.

[0017] The present invention also discloses a control method for the multi-degree-of-freedom co-drive imitating human five-finger dexterous hand, comprising the following steps: Coordinated control of base joint bending and lateral freedom: When the base joint needs to swing sideways, the first drive motor rotates forward or reverse, and the second drive motor rotates in the same direction as the first drive motor. After passing through their respective transmission chains, the first duplex gear and the second duplex gear also rotate in the same direction. After passing through the differential mechanism, since the two input gears of the differential mechanism rotate in the same direction, the two ends of the output bevel gear will be subjected to the same circumferential force, and then revolve, and the finger will rotate around the side swing axis. The differential mechanism has achieved the effect of applying the forces of the first and second drive motors to the output bevel gear. At this time, the force of the third drive motor is added by the bent axis to achieve triple torque superposition. The third drive motor rotates in the opposite direction to the first drive motor, driving the third single output bevel gear to rotate around the side swing axis. The upper part of the entire finger remains as a rigid whole and does not move, and only rotates around the side swing axis. When the base joint needs to bend, the first drive motor rotates forward or reverse, and the second drive motor rotates in the opposite direction to the first drive motor. After passing through their respective transmission chains, the first duplex gear and the second duplex gear also rotate in the opposite direction. After passing through the differential mechanism, due to the opposite rotation of the two input gears of the differential mechanism, the two ends of the output bevel gear will be subjected to two equal and opposite circumferential forces, and then rotate around its own axis. At this time, the third drive motor is controlled to control the third single output bevel gear to rotate at the same angular velocity after passing through the transmission chain. Then, the upper part of the entire finger remains rigid and motionless, and only rotates around the bending axis. Coordinated control of the bending degrees of freedom in the joints: When the middle joint needs to bend, the first drive motor rotates forward or reverse, and the second drive motor rotates in the opposite direction to the first drive motor. After passing through their respective transmission chains, the first duplex gear and the second duplex gear also rotate in the opposite direction. After passing through the differential mechanism, since the two input gears of the differential mechanism rotate in opposite directions, the two ends of the output bevel gear will be subjected to two equal and opposite circumferential forces, and then rotate around its own axis. At this time, the third drive motor is controlled to control the third single output bevel gear to rotate at the opposite angular velocity after passing through the transmission chain. Then, at the middle joint, the output bevel gear of the differential mechanism and the third single output bevel gear rotate in opposite directions, causing the planetary gear to rotate, that is, the bending of the middle joint. Distal joint coupling control: When the left side plate rotates an angle, the first gear remains stationary, and the fourth gear rotates a corresponding angle according to the coupling ratio.

[0018] The multi-degree-of-freedom co-driven humanoid five-finger dexterous hand and control method of the present invention have the following advantages: the present invention introduces a spatial gear train mechanism to design a humanoid five-finger dexterous hand, which realizes the mutual coupling control of three active degrees of freedom: base joint bending, base joint lateral swing, and middle joint bending. Each active degree of freedom is coordinated by three motors, which simplifies the finger space and increases the output force. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the multi-degree-of-freedom co-driven human five-finger dexterous hand of the present invention; Figure 2 This is a schematic diagram of the internal structure of the multi-degree-of-freedom co-driven human five-finger dexterous hand of the present invention; Figure 3 This is a schematic diagram of the structure in which a single finger of the present invention is fixed to the back plate through a screw hole; Figure 4 A schematic diagram of a single finger structure of the present invention; Figure 5 Schematic diagram of the base joint structure of the present invention; Figure 6 This is a schematic diagram of the control states of three motors of the present invention; Figure 7 This is a schematic structural diagram of the first transmission chain of the present invention; Figure 8 Schematic diagram of the second transmission chain structure of the present invention; Figure 9 This is a schematic diagram of the third transmission chain structure of the present invention; Figure 10 Schematic diagram of the base joint differential mechanism structure of the present invention; Figure 11 This is a schematic structural diagram of the other side of the base joint differential mechanism of the present invention; Figure 12This is a schematic diagram of the motion of the base joint differential mechanism of the present invention; Figure 13 Schematic diagram of the structure of the middle joint mechanism of the present invention; Figure 14 This is a schematic structural diagram of the distal phalanx underdrive mechanism of the present invention; Explanation of the marks in the figure: 1. Palm back plate; 2. Palm front plate; 3. Finger; 31. Motor fixing frame; 32. Servo motor; 33. Motor shaft bevel gear; 34. Transmission bevel gear; 35. Motor fixing frame small plate; 36. Side swing axis; 37. Bending axis; 321. First drive motor; 322. Second drive motor; 323. Third drive motor; 331. First motor shaft bevel gear; 332. Second motor shaft bevel gear; 333. Third motor shaft gear; 341. First duplex gear; 342. Second duplex gear; 343. Third duplex gear; 344. Third bevel gear; 345. Third single output bevel gear; 346. Output bevel gear; 38. Planet carrier; 39. Middle joint shaft; 40. Left cylindrical gear; 41. Right side plate; 42. Left side plate; 43. Gear; 44, fingertip; 431, first gear; 432, second gear; 433, third gear; 434, fourth gear. DETAILED DESCRIPTION

[0020] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of a multi-degree-of-freedom co-driven human five-finger dexterous hand and a control method of the present invention in conjunction with the accompanying drawings.

[0021] like Figure 1 As shown, a multi-degree-of-freedom co-driven human-like five-finger dexterous hand of the present invention comprises a palm back panel 1, a palm front panel 2, and five fingers 3. The five fingers 3 have a total of 20 degrees of freedom, of which 15 are active degrees of freedom and 5 are passive degrees of freedom. The five fingers 3 adopt a modular design and have exactly the same structure, which is convenient for manufacturing and replacement, and reduces the cost of subsequent maintenance. Each finger has 3 active degrees of freedom and 1 passive degree of freedom, of which the 3 active degrees of freedom are the base joint bending degree of freedom, the base joint lateral swing degree of freedom, and the middle joint bending degree of freedom, which are coordinated by three servo motors at the bottom of the finger, and the 1 passive degree of freedom is the distal joint bending degree of freedom, which is realized by the planetary gear train under-driven mechanism inside the finger.

[0022] like Figure 2 As shown, the five fingers 3 include the thumb, index finger, middle finger, ring finger, and little finger. The index finger, middle finger, ring finger, and little finger are fixedly connected to the palm back plate 1 through four screw holes on the back of the fingers. The four fingers are staggered at different heights. The thumb lies horizontally in the gap below the middle finger and ring finger and is also fixed through four screw holes. Finally, the palm front plate 2 is covered to form a complete humanoid five-finger dexterous hand.

[0023] The structure of the base joint bending freedom and base joint sideways freedom of a single finger 3 is as follows: Figure 3-5 As shown, it includes a motor fixing frame 31, three servo motors 32, a motor shaft bevel gear 33, a transmission bevel gear 34, a motor fixing frame small plate 35, a side swing shaft 36 and a bending shaft 37. The motor fixing frame 31 is fixedly mounted on the palm back plate 1 by screws, and the three servo motors 32 are fixedly mounted on the motor fixing frame 31 by screws. The end of the motor shaft is fixedly connected to the motor shaft bevel gear 33, and the motor shaft bevel gear 33 is engaged with the respective transmission bevel gears 34. The movement of the finger 3 is controlled by the transmission bevel gear 34. The motor fixing frame small plate 35 is fixedly mounted on the far end of the motor fixing frame 31. A bearing hole is respectively opened at the inner end of the motor fixing frame 31 and the motor fixing frame small plate 35. Bearings are respectively put on both ends of the side swing shaft 36 and placed in the bearing holes. A hole is dug in the middle of the side swing shaft 36, and the bending shaft 37 passes through it and is fixed with structural adhesive, so that the two shafts are fixedly connected as one to form a cross rod. The movement of the base joint is based on this cross rod.

[0024] The three servo motors 32 are respectively the first drive motor 321, the second drive motor 322, and the third drive motor 323 from left to right. The corresponding motor shaft bevel gears 33 are respectively the first motor shaft bevel gear 331, the second motor shaft bevel gear 332, and the third motor shaft gear 333. The matched transmission bevel gears 34 are respectively the first duplex gear 341, the second duplex gear 342, and the third duplex gear 343. Each degree of freedom of motion is controlled by the three motors together. The control state is as follows: Figure 6 As shown: 1 represents the state of the first drive motor.

[0025] like Figure 7 As shown, the motor shaft end of the first drive motor 321 is securely connected to the flanged first motor shaft bevel gear 331, locked with a set screw on the first motor shaft bevel gear 331. The first motor shaft bevel gear 331 then meshes with the first duplex gear 341. The first duplex gear 341 consists of two identical bevel gears mounted back-to-back. The end faces of the two bevel gears are bonded together with structural adhesive to form the duplex gear.

[0026] like Figure 8 As shown, the motor shaft end of the second drive motor 322 is fixedly connected to the second motor shaft bevel gear 332, secured with structural adhesive. The second motor shaft bevel gear 332 meshes with the second duplex gear 342. The second duplex gear 342 consists of two bevel gears, one small and one small. The flange shaft of the small gear passes through the hole of the large gear and is fixed together with structural adhesive to form the duplex gear.

[0027] like Figure 9As shown, the motor shaft end of the third drive motor 323 is securely connected to the third motor shaft gear 333, secured with structural adhesive. The third motor shaft gear 333 meshes with a third duplex gear 343. The third duplex gear 343 consists of a cylindrical gear and a bevel gear. The end faces of the cylindrical gear and the bevel gear are securely bonded with structural adhesive to form a duplex gear. This duplex gear is mounted on the shaft of the second drive motor 322 via a rolling bearing. The third duplex gear 343 meshes with a third bevel gear 344, which is mounted on the side swing shaft 36 via a rolling bearing. The third bevel gear 343 further meshes with the third single-bevel output bevel gear 345 on the left side.

[0028] The three transmission chains are: First drive motor 321 → first motor shaft bevel gear 331 → first double gear 341 Second drive motor 322 → second motor shaft bevel gear 332 → second double gear 342 Third drive motor 323 → third motor shaft gear 333 → third double gear 343 → third bevel gear 344 → third single output bevel gear 345 Finger 3 realizes base joint bending and side swing through base joint differential mechanism. Figure 10 、 11 As shown, it includes a first double gear 341, a second double gear 342, an output bevel gear 346, a third bevel gear 344 and a third single output bevel gear 345. The motion diagram of the base joint differential mechanism is shown in FIG. Figure 12 As shown, the dotted arrow indicates the rotation direction of the motor shaft bevel gear 33. A circle with a cross indicates that the motor shaft bevel gear 33 orbits inward perpendicular to the paper, and a circle with a dot indicates that the motor shaft bevel gear 33 orbits outward perpendicular to the paper. The inner gears in the figure are the first duplex gear 341, the second duplex gear 342, and the output bevel gear 346. The outer gears are the third bevel gear 344 and the third single-bevel output bevel gear 345. The output bevel gear 346 is mounted on a curved shaft 37, the other end of which passes through the third single-bevel output bevel gear 345.

[0029] The coordinated control principle of the base joint bending degree of freedom and the base joint lateral degree of freedom is as follows: When the base joint needs to swing laterally, the first drive motor 321 rotates forward or reverse, while the second drive motor 322 rotates in the same direction as the first drive motor 321. After passing through their respective transmission chains, the first and second double gears 341 and 342 also rotate in the same direction. After passing through the differential mechanism, the two input gears rotate in the same direction, and the output bevel gear 346 is subjected to the same circumferential force at both ends, causing it to revolve, causing the finger to rotate about the lateral swing axis 36. The differential mechanism already applies the forces of the first and second drive motors 321 and 322 to the output bevel gear 346. At this point, the force of the third drive motor 323 is added via the curved shaft 37 to achieve triple torque superposition. At this point, the third drive motor 324 rotates in the opposite direction to the first drive motor 321, driving the third single output bevel gear 345 to rotate about the lateral swing axis 36. The upper portion of the entire finger remains rigid and stationary, rotating only about the lateral swing axis 36.

[0030] When the base joint needs to bend, the first drive motor 321 rotates forward or reverse, and the second drive motor 322 rotates in the opposite direction to the first drive motor 321. After passing through their respective transmission chains, the first duplex gear 341 and the second duplex gear 342 also rotate in the opposite direction. After passing through the differential mechanism, due to the opposite rotation of the two input gears of the differential mechanism, the two ends of the output bevel gear 346 are subjected to two equal and opposite circumferential forces, thereby rotating about its own axis. At this time, the third drive motor 323 is controlled to control the third single output bevel gear 345 to rotate at the same angular velocity after passing through the transmission chain. The upper part of the entire finger remains rigid and motionless, rotating only about the bending axis.

[0031] The bending freedom of the middle joint of a single finger 3 is as follows Figure 13As shown, the middle joint is a planetary gear train structure, the output bevel gear 346 of the differential mechanism serves as the first center gear, the third single-fold output bevel gear 345 serves as the second center gear, and the middle knuckle serves as the planetary gear. Both the first center gear and the second center gear are engaged with the planetary gears, and the three constitute a planetary gear train. The reverse rotation of the first center gear (the output bevel gear 346 of the differential mechanism) and the second center gear (the third single-fold output bevel gear 345) causes the planetary gears to rotate, that is, the bending of the middle joint. Specifically, the middle joint bending degree of freedom structure includes the third single-bevel output bevel gear 345, the output bevel gear 346, the planet carrier 38, the middle joint shaft 39, the left cylindrical gear 40, and the right side plate 41. The planet carrier 38 is a curved connecting rod, one end of which is mounted on the base joint's bending shaft 37 via a rolling bearing, and the other end is mounted on the middle joint shaft 39 via a rolling bearing. The left side of the middle joint shaft 39 is bonded to the left cylindrical gear 40 with structural adhesive, and the left cylindrical gear 40 meshes with the small half of the internal gear at the top of the third single-bevel output bevel gear 345. The right side of the middle joint shaft 39 is bonded to the right side plate 41 with structural adhesive, and the right side plate 41 meshes with the small half of the external gear at the top of the output bevel gear 346 below. When the small half of the external gear on the upper end of the rightmost output bevel gear 346 and the small half of the internal gear on the upper end of the third single-fold output bevel gear 345 on the left rotate in the same direction, the planetary gear revolves, and at this time the proximal phalanx and the middle phalanx rotate together around the bending axis 37 of the base joint as a rigid whole; when the small half of the external gear on the upper end of the rightmost output bevel gear 346 and the small half of the internal gear on the leftmost third single-fold output bevel gear 345 rotate in opposite directions, the planetary carrier remains stationary and the planetary gear rotates on its own, and at this time the proximal phalanx does not move, while the middle phalanx bends around the middle phalanx axis.

[0032] The principle of coordinated control of the bending degrees of freedom of the joint is as follows: When the middle joint needs to bend, the first drive motor 321 rotates forward or reverse, and the second drive motor 322 rotates in the opposite direction to the first drive motor 321. After passing through their respective transmission chains, the first duplex gear 341 and the second duplex gear 342 also rotate in the opposite direction. After passing through the differential mechanism, due to the opposite rotation of the two input gears of the differential mechanism, the two ends of the output bevel gear 346 will be subjected to two equal and opposite circumferential forces, thereby rotating about its own axis. At this time, the third drive motor 323 is controlled to control the third single-bevel output bevel gear 345 to rotate at the opposite angular velocity after passing through the transmission chain. At the middle joint, the opposite rotation of the first center gear (the output bevel gear 346 of the differential mechanism) and the second center gear (the third single-bevel output bevel gear 345) causes the planetary gear to rotate, which is the bending of the middle joint.

[0033] Distal joint bending freedom structure Figure 14As shown, the mechanism comprises a left side plate 42, four gears 43, and a fingertip 44. The four gears 43 include a first gear 431, a second gear 432, a third gear 433, and a fourth gear 434. The four gears mesh sequentially, with the bottom first gear 431 serving as the first center gear, the middle second gear 432 and third gear 433 serving as planetary gears, and the top fourth gear 434 serving as the second center gear. The distal phalanx moves in a coupled, underdriven manner through a planetary gear system. When the middle phalanx rotates an angle, the distal phalanx also rotates a corresponding angle according to a certain coupling ratio, which is determined by the gear ratio of the four gears 43. The first gear 431 is bonded to the planetary carrier 38 of the central joint described above with structural adhesive and can be considered a fixed frame in this mechanism. The second and third gears 432, 433 are fixed to the left side plate 42 via bearings. The left side plate 42 serves as the planetary carrier of the distal phalanx planetary gear system. The lower end of the left side plate 42 is fixedly connected to the central joint shaft 39. The top fourth gear 434 is integral with the fingertip 44.

[0034] Distal joint coupling control: When the middle phalanx (left side plate 42) rotates an angle, that is, the planetary carrier of the distal phalanx planetary gear system rotates an angle, the first center wheel (first gear 431) does not move, so the second center wheel (fourth gear 434) will rotate a corresponding angle according to the coupling ratio. The middle phalanx and distal phalanx of the human hand have the same bending direction, so this mechanism is equipped with two planetary gears in the middle to adjust the rotation direction of the distal phalanx so that it is consistent with the rotation direction of the middle phalanx.

[0035] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A multi-degree-of-freedom co-driven humanoid five-finger dexterous hand, comprising a palm back plate (1), a palm front plate (2) and five fingers (3), wherein the five fingers (3) include a thumb, an index finger, a middle finger, a ring finger and a little finger, the index finger, the middle finger, the ring finger and the little finger are fixedly connected to the palm back plate (1), the four fingers are staggered in height, the thumb lies horizontally in the gap below the middle finger and the ring finger and is fixedly connected to the palm back plate (1), and finally the palm front plate (2) is covered to form a complete humanoid five-finger dexterous hand, characterized in that: The five fingers (3) have a total of 20 degrees of freedom, of which 15 are active degrees of freedom and 5 are passive degrees of freedom. The five fingers (3) adopt a modular design and have exactly the same structure. Each finger has 3 active degrees of freedom and 1 passive degree of freedom. The 3 active degrees of freedom are base joint bending freedom, base joint lateral swing freedom, and middle joint bending freedom, which are controlled by three servo motors at the bottom of the finger. The 1 passive degree of freedom is the distal joint bending freedom, which is realized by the planetary gear under-actuated mechanism inside the finger.

2. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 1, characterized in that: The base joint bending freedom and base joint lateral swing freedom structure of a single finger (3) comprises a motor fixing frame (31), three servo motors (32), a motor shaft bevel gear (33), a transmission bevel gear (34), a motor fixing frame small plate (35), a lateral swing shaft (36) and a bending shaft (37), wherein the motor fixing frame (31) is fixedly mounted on the palm back plate (1), the three servo motors (32) are fixedly mounted on the motor fixing frame (31), the motor shaft end is fixedly connected to the motor shaft bevel gear (33), and the motor shaft bevel gear (33) is connected to the respective transmission bevel gears. The movable bevel gear (34) is engaged, and the movement of the finger (3) is controlled by the transmission bevel gear (34). The motor fixing frame small plate (35) is fixedly installed on the far end of the motor fixing frame (31). The inner end of the motor fixing frame (31) and the motor fixing frame small plate (35) each have a bearing hole. The two ends of the side swing shaft (36) are respectively covered with bearings and placed in the bearing holes. The middle of the side swing shaft (36) is dug with a hole, and the bending shaft (37) passes through it and is fixed, so that the two shafts are fixedly connected as one, forming a cross rod. The movement of the base joint is based on this cross rod.

3. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 2, characterized in that: The three servo motors (32) are respectively a first drive motor (321), a second drive motor (322), and a third drive motor (323) from left to right; the corresponding motor shaft bevel gears (33) are respectively a first motor shaft bevel gear (331), a second motor shaft bevel gear (332), and a third motor shaft gear (333); the matched transmission bevel gears (34) are respectively a first double gear (341), a second double gear (342), and a third double gear (343); and each degree of freedom of motion is controlled by the three motors.

4. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 3, characterized in that: The motor shaft end of the first drive motor (321) is fixedly connected to the first motor shaft bevel gear (331) with a flange and locked with a top screw on the first motor shaft bevel gear (331). The first motor shaft bevel gear (331) is then meshed with the first duplex gear (341); the first duplex gear (341) is composed of two bevel gears of the same specification installed back to back, and the end faces of the two bevel gears are fixedly connected together to form a duplex gear.

5. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 4, characterized in that: The motor shaft end of the second drive motor (322) is fixedly connected to the second motor shaft bevel gear (332), and the second motor shaft bevel gear (332) is meshed with the second duplex gear (342). The second duplex gear (342) is composed of two large and small bevel gears. The flange shaft of the small gear passes through the hole of the large gear and is fixedly connected together to form a duplex gear.

6. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 5, characterized in that: The motor shaft end of the third drive motor (323) is fixedly connected to the third motor shaft gear (333), and the third motor shaft gear (333) is meshed with the third duplex gear (343). The third duplex gear (343) is composed of a cylindrical gear and a bevel gear. The end face of the cylindrical gear and the end face of the bevel gear are fixedly connected together to form a duplex gear. The third duplex gear (343) is mounted on the shaft of the second drive motor (322) through a rolling bearing. The third duplex gear (343) is meshed with the third bevel gear (344). The third bevel gear (344) is mounted on the side swing shaft (36) through a rolling bearing. The third bevel gear (343) is then meshed with the third single-output bevel gear (345) on the left side.

7. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 6, characterized in that: The finger (3) realizes base joint bending and lateral swing through a base joint differential mechanism, wherein the base joint differential mechanism comprises a first double gear (341), a second double gear (342), an output bevel gear (346), a third bevel gear (344) and a third single output bevel gear (345), wherein the output bevel gear (346) is sleeved on a bending shaft (37), and the other end of the bending shaft (37) passes through the third single output bevel gear (345).

8. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 7, characterized in that: The middle joint bending freedom structure comprises a third single-fold output bevel gear (345), an output bevel gear (346), a planetary carrier (38), a middle joint shaft (39), a left cylindrical gear (40) and a right side plate (41). The planetary carrier (38) is a bent connecting rod, one end of which is sleeved on the bending shaft (37) of the base joint through a rolling bearing, and the other end is sleeved on the middle joint shaft (39) through a rolling bearing. The left side of the middle joint shaft (39) is bonded and fixed to the left cylindrical gear (40). The left cylindrical gear (40) is meshed with the small half internal gear at the upper end of the third single-fold output bevel gear (345). The right side of the middle joint shaft (39) is fixed to the right side plate (41). Together, the right side plate (41) meshes with the small half external gear on the upper end of the output bevel gear (346) below. When the small half external gear on the upper end of the rightmost output bevel gear (346) and the small half internal gear on the upper end of the third single-fold output bevel gear (345) on the left rotate in the same direction, the planetary gear revolves, and at this time, the proximal phalanx and the middle phalanx act as a rigid whole and rotate together around the bending axis (37) of the base joint; when the small half external gear on the upper end of the rightmost output bevel gear (346) and the small half internal gear on the third single-fold output bevel gear (345) on the left rotate in opposite directions, the planetary carrier remains stationary and the planetary gear rotates. At this time, the proximal phalanx remains stationary and the middle phalanx bends around the middle phalanx axis.

9. The multi-degree-of-freedom co-driven five-finger dexterous hand according to claim 8, characterized in that: The distal joint bending freedom comprises a left side plate (42), four gears (43) and a fingertip (44); the four gears (43) comprise a first gear (431), a second gear (432), a third gear (433) and a fourth gear (434); the four gears are meshed in sequence; the first gear (431) is fixed on the planetary frame (38) of the middle joint and can be regarded as a fixed frame in this mechanism; the second gear (432) and the third gear (433) are fixed on the left side plate (42) through bearings; the left side plate (42) serves as the planetary frame of the distal finger joint planetary gear system; the lower end of the left side plate (42) is fixedly connected to the middle joint shaft (39); the top fourth gear (434) is integrated with the fingertip (44).

10. A control method for a multi-degree-of-freedom co-drive human five-finger dexterous hand according to any one of claims 1 to 9, characterized in that: The steps include: Coordinated control of base joint bending and lateral freedom: When the base joint needs to swing sideways, the first drive motor (321) rotates forward or reverse, and the second drive motor (322) rotates in the same direction as the first drive motor (321). After passing through their respective transmission chains, the first double gear (341) and the second double gear (342) also rotate in the same direction. After passing through the differential mechanism, since the two input gears of the differential mechanism rotate in the same direction, the two ends of the output bevel gear (346) will be subjected to the same circumferential force, and then revolve, and the finger will rotate around the side swing shaft (36). The differential mechanism has been realized. The invention realizes that the forces of the first drive motor (321) and the second drive motor (322) are both applied to the output bevel gear (346). At this time, the force of the third drive motor (323) is added by using the bending shaft (37) to realize triple torque superposition. The third drive motor (324) rotates in the opposite direction to the first drive motor (321), driving the third single-fold output bevel gear (345) to rotate around the side swing shaft (36). The upper part of the entire finger remains as a rigid whole and does not move, and only rotates around the side swing shaft (36). When the base joint needs to bend, the first drive motor (321) rotates forward or reverse, and the second drive motor (322) rotates in the opposite direction to the first drive motor (321). After passing through their respective transmission chains, the first double gear (341) and the second double gear (342) also rotate in the opposite direction. After passing through the differential mechanism, due to the opposite rotation of the two input gears of the differential mechanism, the two ends of the output bevel gear (346) are subjected to two equal and opposite circumferential forces, and then rotate around its own axis. At this time, the third drive motor (323) is controlled to control the third single output bevel gear (345) to rotate at the same angular velocity after passing through the transmission chain. Then, the upper part of the entire finger remains as a rigid whole and does not move, and only rotates around the bending axis. Coordinated control of the bending degrees of freedom in the joints: When the middle joint needs to bend, the first drive motor (321) rotates forward or reverse, and the second drive motor (322) rotates in the opposite direction to the first drive motor (321). After passing through their respective transmission chains, the first double gear (341) and the second double gear (342) also rotate in the opposite direction. After passing through the differential mechanism, due to the opposite rotation of the two input gears of the differential mechanism, the two ends of the output bevel gear (346) are subjected to two equal and opposite circumferential forces, and then rotate around its own axis. At this time, the third drive motor (323) is controlled to control the third single output bevel gear (345) to rotate at the opposite angular velocity after passing through the transmission chain. Then, at the middle joint, the opposite rotation of the output bevel gear (346) of the differential mechanism and the third single output bevel gear (345) causes the planetary gear to rotate, that is, the bending of the middle joint. Distal joint coupling control: When the left side plate (42) rotates an angle, the first gear (431) remains stationary, and the fourth gear (434) rotates a corresponding angle according to the coupling ratio.

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