A linkage wrist action mechanism
By using a linkage structure and harmonic deceleration unit, the problem that existing bionic wrist devices cannot simulate human wrist movements has been solved, achieving highly bionic wrist movement simulation and enhancing the flexibility and precision of the wrist.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SICHUAN TLIBOT CO LTD
- Filing Date
- 2023-09-20
- Publication Date
- 2026-06-30
AI Technical Summary
Existing bionic wrist devices cannot simulate the up-and-down and left-and-right swinging of the human wrist, lack bionic characteristics, and cannot realistically simulate the movements of the human wrist.
It adopts a linkage structure, which drives the linkage to move in the same or opposite directions through two rotary power devices. Combined with the cross shaft and wrist rotation mechanism, it realizes the compound motion of the wrist swinging up and down and swinging left and right. It uses a harmonic deceleration unit and flexible bearings for power transmission and angle amplification.
It achieves highly biomimetic wrist movements, capable of simulating the up-and-down, left-and-right rotations of the human wrist, or a combination of both, thus improving the flexibility and precision of wrist movements.
Smart Images
Figure CN117283601B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bionic wrist technology, and specifically relates to a linkage-type wrist action mechanism. Background Technology
[0002] A bionic hand structure refers to a bionic machine that is powered to mimic the morphology, structure, and movements of biological organisms. It has an adaptive grasping function and can adapt to grasping various objects. It can be used in different situations to reduce the need for complex sensing and real-time control, and improve the stability and accuracy of grasping. It can be widely used in industrial, agricultural, and service industry robots or as a prosthetic hand for people with disabilities.
[0003] Patent application CN201922237905.1 discloses an underactuated bionic wrist device, including a wrist disc base, a prosthetic hand disc base, and a steering bracket. The steering bracket includes a first support rod group and a second support rod group arranged in a cross configuration. Each of the first and second support rod groups contains at least one support rod. The support rods in the first and second support rod groups are located in different parallel vertical planes. The support rods in the first and second support rod groups have the same inclination angle, and both ends of each support rod are rotatably hinged to the upper end face of the wrist disc base and the lower end face of the prosthetic hand disc base, respectively. Traction ropes passing through the wrist disc base are provided on both the first and second support rod groups for pulling the support rods to rotate. This invention can realistically simulate human wrist movement, achieving large-angle rotational movements, facilitating connection with a prosthetic hand, and providing greater flexibility.
[0004] However, a real wrist cannot rotate on its own axis, so the aforementioned wrist device lacks biomimicry. Furthermore, the device cannot simulate up-and-down or left-and-right wrist movements, thus failing to mimic real wrist actions. Summary of the Invention
[0005] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a linkage wrist action mechanism that can simulate the up-and-down and left-and-right swinging of the human wrist.
[0006] The technical solution adopted in this invention is as follows:
[0007] A linkage-type wrist action mechanism includes a forearm structure, a cross shaft, and a wrist rotation mechanism. The forearm structure is rotatably connected to the cross shaft, and the wrist rotation mechanism is rotatably connected to both sides of the cross shaft. The rotation axes between the forearm structure and the cross shaft, and between the cross shaft and the wrist rotation mechanism, are perpendicular. Two rotary power devices are mounted on the forearm structure. The outer edge of the output end of each rotary power device is rotatably connected to a connecting rod. The other end of the connecting rod is connected to the corresponding side of the wrist rotation mechanism via a ball joint. The connection point between the connecting rod and the wrist rotation mechanism is offset from the rotation axis of the wrist rotation mechanism.
[0008] When the two rotary power devices of this invention drive the two connecting rods to move in the same direction and at the same speed, the wrist rotation mechanism has no torque relative to the vertical axis of the cross shaft, and the wrist rotation mechanism only rotates up and down, simulating the up-and-down swinging of the human wrist. When the two rotary power devices drive the two connecting rods to move in opposite directions and at the same speed, the torque of the wrist rotation mechanism relative to the horizontal axis of the cross shaft cancels out, and the wrist rotation mechanism only rotates left and right, simulating the left-and-right swinging of the human wrist. Under other driving conditions, the wrist rotation mechanism performs a combined up-and-down and left-and-right swinging motion. The wrist action mechanism of this invention can simulate the up-and-down rotation, left-and-right rotation, or a combination of both of the human wrist, exhibiting a high degree of biomimicry.
[0009] In a preferred embodiment of the present invention, the wrist rotation mechanism includes a wrist connector rotatably connected to a cross shaft, a palm connector rotatably connected to the wrist connector, and a rotation amplification component for driving the palm connector to rotate relative to the wrist connector is disposed between the palm connector and the wrist connector. When the wrist connector rotates up and down relative to the cross shaft, the palm connector rotates with the wrist connector. The rotation amplification component can drive the palm connector to rotate further relative to the wrist connector, thus amplifying the rotation angle of the palm connector and simulating the actual rotation angle of the human wrist.
[0010] In a preferred embodiment of the present invention, the rotation amplification assembly includes a fixed gear, which is fixed relative to the cross shaft, and a driven gear is provided on the palm connector. The fixed gear and the driven gear mesh. Since the fixed gear is fixed relative to the cross shaft, when the palm connector rotates with the wrist connector, the driven gear on it will mesh with the driving gear for transmission, and the palm connector will rotate further relative to the wrist connector, thereby amplifying the rotation angle of the palm connector.
[0011] As a preferred embodiment of the present invention, the rotary power device includes a central shaft, a motor stator connected to the central shaft, a motor rotor sleeved on the motor stator, a harmonic reduction unit connected to the motor rotor, the output end of the harmonic reduction unit being rotatably connected to the central shaft, the output end of the harmonic reduction unit being meshed with a harmonic rigid wheel, the harmonic rigid wheel being fixed to the forearm structure, and a rear cover being fixed to one end of the central shaft, the rear cover being fixed to the harmonic rigid wheel.
[0012] The output speed of the harmonic reducer is significantly lower than that of the cam, resulting in a stable and low-speed output for the harmonic reducer. The harmonic reducer meshes with the harmonic gear, providing high transmission accuracy at the output compared to the cam. The output of the harmonic reducer is rotatably connected to the central shaft, ensuring stable support for its output.
[0013] As a preferred embodiment of the present invention, the harmonic reduction unit includes a cam, which is fixed on the motor rotor. A flexible bearing is mounted on the cam, and a flexible wheel is sleeved on the outer ring of the flexible bearing. The flexible wheel meshes with the harmonic rigid wheel. The number of teeth on the flexible wheel is less than the number of teeth on the harmonic rigid wheel. An output flange is fixed on the flexible wheel, and the outer edge of the output flange is rotatably connected to the connecting rod.
[0014] When the motor is powered on, the motor rotor rotates relative to the motor stator. The motor rotor drives the cam to rotate, and the cam drives the flex wheel to mesh with the harmonic rigid wheel through a flexible bearing. If the number of teeth on the flex wheel is N less than the number of teeth on the harmonic rigid wheel, then when the cam rotates one revolution, the flex wheel rotates N teeth relative to the harmonic rigid wheel. This results in a greater speed reduction for the output flange connected to the flex wheel, ensuring a stable output force, and ensuring transmission accuracy through gear transmission.
[0015] As a preferred embodiment of the present invention, the flexible wheel is rotatably connected to the central shaft, so that the flexible wheel can be supported by the central shaft and the stability of the flexible wheel during rotation is guaranteed.
[0016] In a preferred embodiment of the present invention, the inner side of the cam is connected to the central shaft via a rolling bearing. The central shaft reliably supports the cam, and the central shaft and the cam can rotate relative to each other.
[0017] In a preferred embodiment of the present invention, both the cam and the flexible bearing are elliptical in shape, and the flexible wheel meshes with the harmonic rigid wheel at two positions. The flexible bearing pushes the flexible wheel to engage with the harmonic rigid wheel from two points, ensuring stable transmission between the flexible wheel and the harmonic rigid wheel.
[0018] In a preferred embodiment of the present invention, the rotary power device further includes a crossed roller bearing, wherein the inner ring of the crossed roller bearing is integrally formed or fixedly connected to the output flange, and the outer ring of the crossed roller bearing is integrally formed or fixedly connected to the harmonic rigid wheel. The outer ring of the crossed roller bearing provides stable support for the harmonic rigid wheel.
[0019] In a preferred embodiment of the present invention, a wiring hole is provided on the central shaft, through which the stator wiring of the motor passes. The wiring passing through the wiring hole facilitates wiring. The beneficial effects of the present invention are:
[0020] When the two rotary power devices of this invention drive the two connecting rods to move in the same direction and at the same speed, the wrist rotation mechanism has no torque relative to the vertical axis of the cross shaft, and the wrist rotation mechanism only rotates up and down, simulating the up-and-down swinging of the human wrist. When the two rotary power devices drive the two connecting rods to move in opposite directions and at the same speed, the torque of the wrist rotation mechanism relative to the horizontal axis of the cross shaft cancels out, and the wrist rotation mechanism only rotates left and right, simulating the left-and-right swinging of the human wrist. Under other driving conditions, the wrist rotation mechanism performs a combined up-and-down and left-and-right swinging motion. The wrist action mechanism of this invention can simulate the up-and-down rotation, left-and-right rotation, or a combination of both of the human wrist, exhibiting a high degree of biomimicry. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of the present invention;
[0022] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;
[0023] Figure 3 This is a cross-sectional view of a rotary power unit;
[0024] Figure 4 This is a partial structural diagram of the rotating power unit.
[0025] In the diagram: 1-Forearm structure; 2-Cross shaft; 3-Wrist rotation mechanism; 4-Rotation power unit; 5-Connecting rod; 31-Wrist connector; 32-Palm connector; 33-Fixed gear; 34-Driven gear; 41-Central shaft; 42-Motor stator; 43-Motor rotor; 44-Harmonic reduction unit; 45-Harmonic rigid wheel; 441-Cam; 442-Flexible bearing; 443-Flexible wheel; 444-Output flange; 411-Rolling bearing; 46-Cross roller bearing; 47-Rear cover. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.
[0028] like Figure 1 and Figure 2 As shown, the linkage-type wrist action mechanism of this embodiment includes a forearm structure 1, a cross shaft 2, and a wrist rotation mechanism 3. The forearm structure 1 is rotatably connected to the cross shaft 2, and the wrist rotation mechanism 3 is rotatably connected to both sides of the cross shaft 2. The rotation axis between the forearm structure 1 and the cross shaft 2, and the rotation axis between the cross shaft 2 and the wrist rotation mechanism 3 are perpendicular. Two rotational power devices 4 are installed on the forearm structure 1. The outer edge of the output end of the rotational power device 4 is rotatably connected to a connecting rod 5. The other end of the connecting rod 5 is connected to the corresponding side of the wrist rotation mechanism 3 through a ball joint. The connection point between the connecting rod 5 and the wrist rotation mechanism 3 is offset from the rotation axis of the wrist rotation mechanism 3.
[0029] When the two rotating power devices 4 drive the two connecting rods 5 to move in the same direction and at the same speed, the wrist rotation mechanism 3 has no torque relative to the vertical axis of the cross shaft 2, and the wrist rotation mechanism 3 only rotates up and down, simulating the up-and-down swinging of the human wrist. When the two rotating power devices 4 drive the two connecting rods 5 to move in opposite directions and at the same speed, the torque of the wrist rotation mechanism 3 relative to the horizontal axis of the cross shaft 2 cancels out, and the wrist rotation mechanism 3 only rotates left and right, simulating the left-and-right swinging of the human wrist. Under other driving conditions, the wrist rotation mechanism 3 performs a combined up-and-down swinging and left-and-right swinging motion. The wrist action mechanism of the present invention can simulate the up-and-down rotation, left-and-right rotation, or a combination of both of the human wrist, and its biomimeticity is high.
[0030] Specifically, the wrist rotation mechanism 3 includes a wrist connector 31, which is rotatably connected to the cross shaft 2. A palm connector 32 is rotatably connected to the wrist connector 31. A rotation amplification component is provided between the palm connector 32 and the wrist connector 31 to drive the palm connector 32 to rotate relative to the wrist connector 31. When the wrist connector 31 rotates up and down relative to the cross shaft 2, the palm connector 32 rotates with the wrist connector 31. The rotation amplification component can drive the palm connector 32 to rotate further relative to the wrist connector 31, thus amplifying the rotation angle of the palm connector 32 and simulating the actual rotation angle of the human wrist.
[0031] The rotation amplification component includes a fixed gear 33, which is fixed relative to the cross shaft 2. A driven gear 34 is provided on the palm connector 32, and the fixed gear 33 and the driven gear 34 mesh. Because the fixed gear 33 is fixed relative to the cross shaft 2, when the palm connector 32 rotates with the wrist connector 31, the driven gear 34 on it will mesh with the driving gear, causing the palm connector 32 to rotate further relative to the wrist connector 31, thus amplifying the rotation angle of the palm connector 32.
[0032] Specifically, such as Figure 3 and Figure 4 As shown, the rotary power device 4 includes a central shaft 41, a motor stator 42 connected to the central shaft 41, a motor rotor 43 sleeved on the motor stator 42, a harmonic reduction unit 44 connected to the motor rotor 43, the output end of the harmonic reduction unit 44 being rotatably connected to the central shaft 41, the output end of the harmonic reduction unit 44 being meshed with a harmonic rigid wheel 45, the harmonic rigid wheel 45 being fixed on the forearm structure 1, and a rear cover 47 being fixed to one end of the central shaft 41, the rear cover 47 being fixed to the harmonic rigid wheel 45.
[0033] The output speed of the harmonic reduction unit 44 is significantly lower than that of the cam 441, resulting in a stable and low-speed output from the harmonic reducer. The harmonic reduction unit 44 meshes with the harmonic rigid wheel 45, thus providing high transmission accuracy at the output of the harmonic reducer relative to the cam 441. The output of the harmonic reduction unit 44 is rotatably connected to the central shaft 41, ensuring stable support for its output.
[0034] The harmonic reduction unit 44 includes a cam 441 fixed to the motor rotor 43. A flexible bearing 442 is mounted on the cam 441, and a flexible wheel 443 is fitted around the outer ring of the flexible bearing 442. The flexible wheel 443 meshes with a harmonic rigid wheel 45, with the number of teeth on the flexible wheel 443 being less than the number of teeth on the harmonic rigid wheel 45. An output flange 444 is fixed to the flexible wheel 443, which is rotatably connected to the central shaft 41. The outer edge of the output flange 444 is rotatably connected to the connecting rod 5. Both the cam 441 and the flexible bearing 442 are elliptical in shape. The flexible wheel 443 meshes with the harmonic rigid wheel 45 in two positions. The flexible bearing 442 pushes the flexible wheel 443 to mesh with the harmonic rigid wheel 45 from two points, ensuring stable transmission between the flexible wheel 443 and the harmonic rigid wheel 45.
[0035] The motor stator 42 and the electronic rotor 43 are built into the flexible wheel 443, which can effectively utilize space, reduce the volume of the rotating power unit 4, and simplify the structure.
[0036] The reduction principle of the harmonic reducer utilizes the relative motion of the flexure 443, the harmonic rigid wheel 45, and the cam 441, primarily through the controllable elastic deformation of the flexure 443 to achieve motion and power transmission. The elliptical cam 441 rotates within the flexure 443, causing the flexure 443 to deform. When the teeth of the flexure 443 at both ends of the major axis of the elliptical cam 441 engage with the teeth of the harmonic rigid wheel 45, the teeth of the flexure 443 at both ends of the minor axis disengage from the teeth of the harmonic rigid wheel 45. For the teeth between the major and minor axes of the cam 441, the gradual engagement (partial engagement) along different sections of the circumference of the flexure 443 and the harmonic rigid wheel 45 is called engagement. The gradual disengagement (partial engagement) is called disengagement. As cam 441 rotates continuously, flexure 443 undergoes continuous deformation, causing the teeth of the two gears to constantly change their original working states in four motions: engagement, disengagement, and retraction, resulting in a tooth-shifting motion. This achieves motion transmission between cam 441 and flexure 443. The harmonic reducer offers smooth transmission, low noise, high motion accuracy, and a backlash of less than 10 arcseconds.
[0037] When the motor is powered on, the motor rotor 43 rotates relative to the motor stator 42. The motor rotor 43 drives the cam 441 to rotate, and the cam 441 drives the flexure wheel 443 to mesh with the harmonic rigid wheel 45 through the flexible bearing 442. The flexible bearing 442 is also elliptical and rotates synchronously with the cam 441. The flexure wheel 443 is made of flexible material and is sleeved on the cam. When the flexible bearing 442 rotates, the teeth of the harmonic rigid wheel 45 block the teeth of the flexure wheel 443, causing the flexure wheel 443 to slide on the flexible bearing 442. Due to the pressing action of the flexible bearing 442, the meshing position of the flexure wheel 443 and the harmonic rigid wheel 45 changes continuously. Since the number of teeth of the flexure wheel 443 is less than the number of teeth of the harmonic rigid wheel 45, the meshing position of the flexure wheel 443 and the harmonic rigid wheel 45 does not change by one revolution when the cam 441 rotates one revolution. If the number of teeth of the flexible wheel 443 is N less than the number of teeth of the harmonic rigid wheel 45, then when the cam 441 rotates one revolution, the flexible wheel 443 rotates N teeth relative to the harmonic rigid wheel 45, thereby the output flange 444 connected to the flexible wheel 443 is greatly decelerated, ensuring a stable output force, and the transmission accuracy is ensured through gear transmission. Figure 4 In the process, the number of teeth of the flexible wheel 443 is two fewer than the number of teeth of the harmonic rigid wheel 45. When the cam 441 rotates one revolution, the flexible wheel 443 rotates two teeth, and the output flange 444 rotates by the corresponding angle with the cam 441.
[0038] To provide support for the cam 441, the inner side of the cam 441 is connected to the central shaft 41 via a rolling bearing 411. The central shaft 41 reliably supports the cam 441, and the central shaft 41 and the cam 441 can rotate relative to each other.
[0039] To support the harmonic rigid wheel 45, the rotary power device further includes a crossed roller bearing 46. The inner ring of the crossed roller bearing 46 is integrally formed or fixedly connected to the output flange 444, and the outer ring of the crossed roller bearing 46 is integrally formed or fixedly connected to the harmonic rigid wheel 45. The outer ring of the crossed roller bearing 46 provides stable support for the harmonic rigid wheel 45.
[0040] A rear cover 47 is fixedly connected to the central shaft 41. The rear cover 47 is fixed to the forearm structure 1. The rear cover 47 and the output flange 444 are respectively located on both sides of the central shaft 41.
[0041] The central shaft 41 is provided with a wiring hole, through which the wiring of the motor stator 42 passes.
[0042] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.
Claims
1. A linkage-type wrist action mechanism, characterized in that: The device includes a forearm structure (1), a cross shaft (2), and a wrist rotation mechanism (3). The forearm structure (1) is rotatably connected to the cross shaft (2), and the wrist rotation mechanism (3) is rotatably connected to both sides of the cross shaft (2). The shafts between the forearm structure (1) and the cross shaft (2) and between the cross shaft (2) and the wrist rotation mechanism (3) are perpendicular. Two rotary power devices (4) are installed on the forearm structure (1). A connecting rod (5) is rotatably connected to the outer edge of the output end of the rotary power device (4). The other end of the connecting rod (5) is connected to the corresponding side of the wrist rotation mechanism (3) through a ball joint. The connection point between the connecting rod (5) and the wrist rotation mechanism (3) is offset from the shaft of the wrist rotation mechanism (3). The wrist rotation mechanism (3) includes a wrist connector (31), which is rotatably connected to a cross shaft (2). A palm connector (32) is rotatably connected to the wrist connector (31). A rotation amplification component for driving the palm connector (32) to rotate relative to the wrist connector (31) is provided between the palm connector (32) and the wrist connector (31). The rotation amplification assembly includes a fixed gear (33) which is fixed relative to the cross shaft (2), and a driven gear (34) is provided on the palm connector (32), and the fixed gear (33) and the driven gear (34) mesh with each other.
2. The linkage-type wrist action mechanism according to claim 1, characterized in that: The rotating power device (4) includes a central shaft (41), a motor stator (42) is connected to the central shaft (41), a motor rotor (43) is sleeved on the motor stator (42), a harmonic reduction unit (44) is connected to the motor rotor (43), the output end of the harmonic reduction unit (44) is rotatably connected to the central shaft (41), the output end of the harmonic reduction unit (44) is meshed with a harmonic rigid wheel (45), the harmonic rigid wheel (45) is fixed on the forearm structure (1), and a rear cover (47) is fixed to one end of the central shaft (41), the rear cover (47) is fixed to the harmonic rigid wheel (45).
3. The linkage-type wrist action mechanism according to claim 2, characterized in that: The harmonic deceleration unit (44) includes a cam (441), which is fixed on the motor rotor (43). A flexible bearing (442) is installed on the cam (441). A flexible wheel (443) is sleeved on the outer ring of the flexible bearing (442). The flexible wheel (443) meshes with the harmonic rigid wheel (45). The number of teeth of the flexible wheel (443) is less than the number of teeth of the harmonic rigid wheel (45). An output flange (444) is fixed on the flexible wheel (443). The outer edge of the output flange (444) is rotatably connected to the connecting rod (5).
4. The linkage-type wrist action mechanism according to claim 3, characterized in that: The flexible wheel (443) is rotatably connected to the central shaft (41).
5. The linkage-type wrist action mechanism according to claim 3, characterized in that: The inner side of the cam (441) is connected to the central shaft (41) by a rolling bearing (411).
6. The linkage-type wrist action mechanism according to claim 3, characterized in that: The cam (441) and the flexible bearing (442) are both elliptical in shape, and the flexible wheel (443) meshes with the harmonic rigid wheel (45) in two positions.
7. The linkage-type wrist action mechanism according to claim 3, characterized in that: The rotary power unit also includes a crossed roller bearing (46), the inner ring of which is integrally formed or fixedly connected to the output flange (444), and the outer ring of which is integrally formed or fixedly connected to the harmonic rigid wheel (45).
8. The linkage-type wrist action mechanism according to claim 3, characterized in that: The central shaft (41) is provided with a wiring hole, through which the wiring of the motor stator (42) passes.