Anthropomorphic robotic mechanical finger
By employing purely mechanical gear transmission and a wear self-diagnosis method, the problems of complex robot finger structure and difficult maintenance have been solved, enabling stable operation and efficient control in extreme environments, reducing costs and extending service life.
Patent Information
- Application Number
- CN202611077043.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-20
- Publication Date
- 2026-08-25
AI Technical Summary
Existing robotic fingers have complex structures, high costs, and complex controls. They lack self-diagnostic capabilities for wear and tear, have high maintenance costs, and are susceptible to sudden malfunctions.
It adopts pure mechanical gear transmission, drives the three phalanges of the finger to bend synchronously through a single power source, and combines pressure sensors and wear self-diagnosis methods to achieve absolute synchronous movement of mechanical joints and wear condition monitoring.
It can operate stably in extreme environments, reduce control difficulty and maintenance costs, respond quickly, and extend the service life of the robotic finger through self-diagnostic functions.
Smart Images
Figure CN122626280A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bionic robotic hand technology, specifically a humanoid robot mechanical finger. Background Technology
[0002] With the continuous development of AI, humanoid robot technology is also constantly innovating and expanding its application scenarios. Among the complex designs of humanoid robots, hand design is one of the most challenging aspects. The key is that the fingers in the hand need to be able to bend and straighten with the same dexterity as human fingers.
[0003] Existing robotic fingers mostly employ a multi-drive source approach, where each phalanx is driven by an independent motor or electric cylinder, working in conjunction with a complex control system to achieve multi-phalanx linkage. This approach suffers from problems such as complex structure, large size, high cost, and complex control. Some solutions use a planetary gear coupling underactuated method, which simplifies the structure to some extent, but still requires the installation of an independent drive motor inside the finger, and the planetary gear system requires high assembly precision and is also costly.
[0004] In addition, existing mechanical fingers generally lack the ability to self-diagnose wear, making it difficult for users to predict the wear status of gears. Often, it is necessary to stop the machine and disassemble it to determine whether the gears need to be replaced, resulting in high maintenance costs and the equipment being prone to failure due to sudden malfunctions. Summary of the Invention
[0005] The purpose of this invention is to provide a humanoid robot mechanical finger to solve the problems mentioned in the background art.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] A humanoid robotic mechanical finger, comprising;
[0008] The fixing frame is provided with a first directional tooth;
[0009] The proximal phalanx drive rod is rotatably connected to the first position of the fixation frame, and one end of the proximal phalanx drive rod is movably connected to the output end of the telescopic device, while the other end is provided with a second directional tooth and is rotatably connected to the distal phalanx linkage rod.
[0010] The middle phalanx linkage rod is rotatably connected to the second position of the fixation frame;
[0011] The driven gear assembly is rotatably connected between the proximal phalanx drive rod and the middle phalanx linkage rod, and meshes with the first directional tooth;
[0012] The middle phalanx drive rod is rotatably connected between the proximal phalanx drive rod and the middle phalanx linkage rod, and is provided with a third directional tooth, which meshes with the driven gear assembly;
[0013] The distal phalanx swing rod is rotatably connected between the distal phalanx linkage rod and the middle phalanx drive rod, and is provided with a fourth directional tooth, which meshes with the second directional tooth.
[0014] In a further technical solution, the driven gear assembly includes a first driven gear and a second driven gear that mesh with each other, the first driven gear meshing with a first directional tooth, and the second driven gear meshing with a third directional tooth.
[0015] In a further technical solution, the first directional tooth, the first driven gear, the second driven gear, and the third directional tooth have the same width and are aligned in a straight line.
[0016] In a further technical solution, the proximal phalanx drive rod and the middle phalanx linkage rod are connected by the same first fixed shaft;
[0017] A second fixed shaft is provided through the middle phalanx drive rod, and the two ends of the second fixed shaft extend to the proximal phalanx drive rod and the middle phalanx linkage rod, respectively.
[0018] A third fixed shaft is provided through the distal phalanx swing rod, and the two ends of the third fixed shaft extend to the middle phalanx drive rod and the distal phalanx linkage rod, respectively.
[0019] At least one fourth fixed shaft is provided in the driven gear assembly, and the two ends of the fourth fixed shaft extend to the proximal phalanx drive rod and the middle phalanx linkage rod.
[0020] A further technical solution involves installing a pressure sensor at the end of the distal phalanx swing rod.
[0021] The beneficial effects of this invention are:
[0022] This invention uses pure mechanical gear transmission and does not rely on elastic elements, steel wire ropes, rubber seals and other components that are prone to aging or affected by temperature / radiation. It can work stably for a long time in extreme environments such as high temperature, low temperature, vacuum and radiation.
[0023] The movement trajectory of the three phalanges is fixed, and the movements are absolutely synchronized. There are no additional degrees of freedom or movement uncertainties introduced by any elastic elements or variable coupling mechanisms.
[0024] Because gear meshing has unidirectional force transmission characteristics, and each directional tooth always maintains contact with the gear, the entire transmission chain has a definite force transmission path in any load direction, and there is no risk of dead point position or self-locking failure.
[0025] This invention uses a single power source. Since the motion trajectory is fixed, only the extension and retraction of the telescopic device needs to be controlled to achieve the bending amount of the mechanical joint. This makes it easy to control, requires low computing power, and can respond quickly.
[0026] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0027] Figure 1 : First three-dimensional structural diagram of the present invention.
[0028] Figure 2 : Second three-dimensional structural diagram of the present invention.
[0029] Figure 3 : Disassembly diagram of the present invention.
[0030] Figure 4 : A first bending structure diagram of the present invention.
[0031] Figure 5 : A second bending structure diagram of the present invention.
[0032] Reference numerals: 1-Fixed frame, 11-First directional tooth, 2-Proximal phalanx drive rod, 21-Curved nozzle, 22-Second directional tooth, 3-Telescopic device, 4-Distal phalanx linkage rod, 5-Middle phalanx linkage rod, 6-Driven gear assembly, 61-First driven gear, 62-Second driven gear, 7-Middle phalanx drive rod, 71-Third directional tooth, 8-Distal phalanx swing rod, 81-Fourth directional tooth, 82-Distal phalanx tip linkage rod, 91-First fixed shaft, 92-Second fixed shaft, 93-Third fixed shaft, 94-Fourth fixed shaft. Detailed Implementation
[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
[0034] Please refer to Figure 1-5 ;
[0035] In existing bionic joints, separate drive devices are usually set up at each joint to obtain greater degrees of freedom. However, in daily application scenarios, multi-degree-of-freedom extension and contraction of each joint is not required. Instead, it makes the structure bulky and the manufacturing and maintenance costs high. This invention provides a low-cost bionic mechanical finger joint that enables the simultaneous rotation and bending of each joint of the bionic finger through strong constraint relationships, so as to meet most application scenarios and is more in line with the movement habits of human fingers.
[0036] Specifically, it includes a fixation frame 1, a proximal phalanx drive rod 2, a middle phalanx drive rod 7, and a distal phalanx swing rod 8; the fixation frame 1 is provided with a first directional tooth 11; when several bionic finger joints are combined to form a bionic mechanical hand, the fixation frame 1 should be installed on the skeleton of the bionic hand.
[0037] The proximal phalanx drive rod 2 is rotatably connected to the first position of the fixing frame 1, and the middle phalanx linkage rod 5 is rotatably connected to the second position of the fixing frame 1. Preferably, the proximal phalanx drive rod 2 and the middle phalanx linkage rod 5 are arranged opposite to each other on the fixing frame 1 and are connected by passing through the fixing frame 1 through the same first fixing shaft 91. In addition, one end of the proximal phalanx drive rod 2 is provided with a curved nozzle 21, which is movably connected to the output end of the telescopic device 3 through the curved nozzle 21, and the other end is provided with a second directional tooth 22. The distal phalanx linkage rod 4 is rotatably connected to the end near the second directional tooth 22. It should be noted that the telescopic device 3 can be installed on the external frame or on the fixing frame 1. In order to optimize the assembly process, it is preferred to install it on the fixing frame 1 as an integral module.
[0038] Driven gear assembly 6 is rotatably connected between proximal phalanx drive rod 2 and middle phalanx linkage rod 5, and meshes with first directional tooth 11. It should be noted that driven gear assembly 6 can be a single gear or a combination of multiple gears. Preferably, driven gear assembly 6 includes a first driven gear 61 and a second driven gear 62 that mesh with each other. The first driven gear 61 meshes with the first directional tooth 11, and the second driven gear 62 meshes with the third directional tooth 71. At least one fourth fixed shaft 94 passes through driven gear assembly 6. The two ends of the fourth fixed shaft 94 extend to the proximal phalanx drive rod 2 and the middle phalanx linkage rod 5. Since the driven gear assembly consists of two gears, there should be two fourth fixed shafts 94.
[0039] The middle phalanx drive rod 7 is rotatably connected between the proximal phalanx drive rod 2 and the middle phalanx linkage rod 5, and is provided with a third directional tooth 71, which meshes with the driven gear assembly 6; a second fixed shaft 92 is provided through the middle phalanx drive rod 7, and the two ends of the second fixed shaft 92 extend to the proximal phalanx drive rod 2 and the middle phalanx linkage rod 5 respectively.
[0040] The distal phalanx swing rod 8 is rotatably connected between the distal phalanx linkage rod 4 and the middle phalanx drive rod 7, and is provided with a fourth directional tooth 81, which meshes with the second directional tooth 22. A third fixed shaft 93 passes through the distal phalanx swing rod 8, with both ends of the third fixed shaft 93 extending to the middle phalanx drive rod 7 and the distal phalanx linkage rod 4, respectively. The other end of the distal phalanx swing rod 8 is the fingertip, which can be fitted with a fingertip sleeve or a tactile sensor to simulate the distal phalanx of a human finger. In addition, to improve stability, a distal phalanx tip linkage rod 82 is provided on one side of the middle phalanx drive rod 7, and the distal phalanx tip linkage rod 82 is connected to the distal phalanx swing rod 8.
[0041] It should be noted that bearings connected to the fixed shaft are provided at each rotating connection point, which is a common technical means to improve the smoothness of rotation.
[0042] In addition, each tooth is evaluated during the design process. Through calculation, the value of the tooth gap between each tooth and the precision machining can be known to ensure tight meshing and prevent loosening. Initial calibration is performed sequentially as a benchmark for intelligent control. However, how to calculate this is no longer an improvement point of this application. Please refer to the existing technology for details, which will not be elaborated here.
[0043] The mechanical joint in this embodiment adopts the principle of "single power source and pure gear forced meshing linkage" to achieve synchronous bending and straightening of three phalanges.
[0044] Initial state: When the telescopic rod of the telescopic device 3 is in the retracted state, the proximal phalanx drive rod 2 is in the extended position, and the entire mechanical joint is in the extended state.
[0045] Bending process: When the telescopic rod of the telescopic device 3 extends, it pushes the bend 21 of the proximal phalanx drive rod 2, causing the proximal phalanx drive rod 2 to swing clockwise around the first fixed axis 91. At this time:
[0046] Proximal phalanx segment: The swing of the proximal phalanx drive rod 2 directly simulates the bending motion of the human proximal phalanx.
[0047] Middle phalanx segment: When the proximal phalanx drive rod 2 swings, it synchronously drives the middle phalanx linkage rod 5 to move, which in turn drives the fourth fixed shaft 94 mounted on it to move. This causes the first driven gear 61 to roll and mesh along the first directional tooth 11 of the fixed frame 1. Since the first directional tooth 11 is fixed and its center of curvature coincides with the first fixed shaft 91, the first driven gear 61 is forced to rotate. This rotation is transmitted to the third directional tooth 71 of the middle phalanx drive rod 7 through the second driven gear 62, causing the middle phalanx drive rod 7 to swing relative to the proximal phalanx drive rod 2, thereby achieving the bending of the middle phalanx. Throughout the process, the widths of the first directional tooth 11, the first driven gear 61, the second driven gear 62, and the third directional tooth 71 are consistent and aligned in a straight line, ensuring smooth transmission.
[0048] Distal phalanx segment: When the middle phalanx drive rod 7 swings, its front end drives the distal phalanx swing rod 8 through the third fixed shaft 93. At the same time, since the fourth directional tooth 81 of the distal phalanx swing rod 8 is always engaged with the second directional tooth 22 of the proximal phalanx drive rod 2, and the two satisfy the aforementioned geometric constraint conditions, the fourth directional tooth 81 can only move along the tooth track of the second directional tooth 22, thereby forcing the distal phalanx swing rod 8 to generate additional swing relative to the proximal phalanx drive rod 2 during the movement, realizing the bending of the distal phalanx.
[0049] Straightening process: When the telescopic rod of telescopic device 3 retracts, the above transmission process is reversed, and the three phalanges straighten synchronously.
[0050] It should be noted that each fixed shaft should be located at the curvature center of the corresponding gear to satisfy the corresponding constraint relationship.
[0051] This invention uses pure mechanical gear transmission and does not rely on elastic elements, steel wire ropes, rubber seals and other components that are prone to aging or affected by temperature / radiation. It can work stably for a long time in extreme environments such as high temperature, low temperature, vacuum and radiation.
[0052] The mechanical joints of this invention achieve linkage through a strong constraint relationship. From a kinematic perspective, there is no redundancy in the three phalanges of this invention. The motion trajectory and angular change rate of the middle phalanx relative to the proximal phalanx are precisely determined by the ratio of the number of teeth of the fixed directional teeth, the driven gear assembly 6, and the third directional teeth 71. The motion trajectory and angular change rate of the distal phalanx relative to the middle phalanx are precisely determined by the ratio of the number of teeth of the second directional teeth 22 and the fourth directional teeth 81. The motion trajectory of the three phalanges is fixed, and the movements are absolutely synchronous. There are no additional degrees of freedom or motion uncertainties introduced by any elastic elements or variable coupling mechanisms.
[0053] From a static perspective, under any equilibrium position, the external load borne by the three phalanges is transmitted to the fixed frame 1 through gear meshing, and is ultimately borne by the fixed frame 1. Since gear meshing has unidirectional force transmission characteristics and each directional tooth always maintains contact with the gear, the entire transmission chain has a definite force transmission path in any load direction, and there is no risk of dead point position or self-locking failure.
[0054] This invention uses a power source with one pole. Since the motion trajectory is fixed, only the extension and retraction of the telescopic device 3 needs to be controlled to achieve the bending amount of the mechanical joint. It is easy to control, has low computing power requirements, and can respond quickly.
[0055] In this embodiment of the invention, a pressure sensor is provided at the end of the distal phalanx swing rod. The pressure sensor is preferably a thin-film pressure sensor or a MEMS pressure sensor, used to detect the pressure of the mechanical finger contacting the object when it grasps the object.
[0056] Because the structure of this invention uses a full gear for forced constraint, the teeth will wear under long-term use or long-term stress, resulting in increased tooth gaps and loose meshing. This causes changes in the bending angle at the joint, and the fingertip cannot reach the reference position under the same extension amount, leading to decreased accuracy and inability to grip objects. To address this, a gear wear self-diagnosis method is proposed, including a control system, a current sensor, and at least one position sensor. Since this technical solution uses a strongly constrained associated structure, wear at any one tooth will eventually be reflected in the rotation angle of the distal phalanx swing rod 8. Therefore, it is only necessary to measure the final rotation angle of the distal phalanx swing rod 8. For this reason, it is preferable to install the position sensor at the third fixed shaft 93.
[0057] The control system includes a microcontroller (MCU) or digital signal processor (DSP) and a storage module. A current sensor is used to detect the operating current of the telescopic device; preferably, the current sensor is a current sampling resistor integrated inside the telescopic device, used to detect the phase current or bus current of the motor. A position sensor is used to obtain the position change of the meshing position. Since a single drive source is used and the meshing points in the transmission chain are connected in series, there is a direct mapping relationship between the load characteristics of the telescopic device and the wear degree of each meshing point. Of course, a benchmark calibration process is performed before the mechanical joint leaves the factory or during initial installation and commissioning to establish a reference benchmark for subsequent diagnosis. This calibration process is carried out under no-load and constant temperature conditions; the specific steps are as follows:
[0058] Step S1: Control the telescopic device to perform at least one forward stroke and at least one reverse stroke;
[0059] The control system controls the telescopic device to extend from its initial position to its maximum bending angle (forward stroke) at the same speed as during the calibration phase (preferably 1 mm / s), and then retract to its initial position (reverse stroke). The diagnostic process is performed under no-load conditions, and the triggering conditions for the diagnostics include, but are not limited to, any of the following:
[0060] Condition a: The mechanical joint is automatically triggered after completing a preset number of bending / straightening action cycles (e.g., triggered once every 1000 cycles).
[0061] Condition b: Automatic triggering after the cumulative running time of the mechanical joint reaches a preset time threshold (e.g., triggering once every 50 hours);
[0062] Condition c: The telescopic device is automatically triggered each time it is powered on.
[0063] Condition d: Triggered when a diagnostic command is received from an external host computer.
[0064] Step S2: During the forward and reverse strokes, the actual angle detection value is obtained through the position sensor, and the drive current detection value is obtained through the current sensor;
[0065] During the forward and reverse strokes, when the finger bone moves to the preset detection angle... When using the same angle during the calibration phase, record the following:
[0066] Arrival in the forward direction The actual angle detection value at that time;
[0067] : Reverse journey to arrive The actual angle detection value at that time;
[0068] Simultaneously, within the stable interval of the middle section of the forward stroke, multiple sampling points of the drive current are collected, and their arithmetic mean is calculated. .
[0069] Step S3: Calculate the angle deviation between the forward and reverse travel at the same target angle based on the actual angle detection value, and use it as a comprehensive backlash characterization quantity;
[0070] Calculate the current angle deviation value:
[0071]
[0072] This angular deviation value It directly reflects the combined angular deviation of the forward and reverse travel under the current gear wear condition.
[0073] Step S4: Calculate the current increment between the current driving current and the reference driving current based on the detected driving current value, and use it as a measure of meshing resistance.
[0074] Temperature compensation for drive current:
[0075]
[0076] in This is the temperature coefficient of the motor winding resistance (0.00393 / °C for copper windings). The current temperature. The temperature at which the calibration was performed.
[0077] Calculate the current increment value:
[0078]
[0079] The current increment It directly reflects the change in meshing resistance.
[0080] Step S5: Determine the gear wear state based on the comprehensive backlash characterization and / or the meshing resistance characterization;
[0081] First, calculate the increment of the angle deviation:
[0082]
[0083] Then, the wear status is determined based on the following collaborative diagnostic logic:
[0084]
[0085] Step S6: Perform the corresponding processing operation according to the gear wear condition;
[0086] (a) Normal state: No processing is performed, and the diagnostic data is recorded.
[0087] (b) Uniform wear on tooth surfaces:
[0088] Based on the increment of angle deviation The drive quantity of the drive source is automatically corrected to compensate for positional deviations caused by gear wear.
[0089] Perform directional adaptive compensation:
[0090] During forward stroke (bending):
[0091] During the reverse stroke (straightening):
[0092] in The angle-position compensation coefficient (determined during the calibration phase) ranges from 0.5 to 1.0, with 0.8 being preferred.
[0093] Automatic compensation function only When activated, it records current wear data.
[0094] (c) Tooth surface damage:
[0095] Output a tooth surface damage alarm signal and reduce the maximum workload to 50% of the rated value.
[0096] (d) Severe integrated wear:
[0097] Output an emergency stop signal to halt the operation of the mechanical joint and maintain its current posture. Upload a complete diagnostic report to the host computer and request immediate maintenance.
[0098] The diagnostic process takes only a few seconds (one complete forward and reverse stroke) and can be completed automatically during robot material changes or standby intervals. There is no need to remove the finger and send it to the testing station, so it does not affect the normal production cycle.
[0099] Pure gear forced linkage is a rigid transmission, without the hysteresis and nonlinear effects of elastic elements. It maintains a stable transmission ratio during long-term operation. Combined with the automatic position compensation function in wear self-diagnosis, even when the gears are gradually worn, the system can still maintain position accuracy by correcting the drive amount, which significantly extends the effective high-precision service life of the fingers.
[0100] Based on the above diagnostic methods, there may be many additional influencing factors, such as bearing wear and lubrication effects after long-term use. However, the ultimate goal of the robotic finger is to achieve a standard bending amount with the same extension amount of the extension device. Assuming that the gears are not worn but the bearings are damaged, resulting in the inability to achieve the standard bending amount, the self-diagnosis method can indirectly reflect that there is a defect in the middle finger of the robotic finger, which requires maintenance.
[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0102] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A humanoid robot mechanical finger, characterized in that: include; A fixing frame (1) is provided with a first directional tooth (11); The proximal phalanx drive rod (2) is rotatably connected to the first position of the fixation frame (1), and one end of the proximal phalanx drive rod (2) is movably connected to the output end of the telescopic device (3), and the other end is provided with a second directional tooth (22), and is rotatably connected to the distal phalanx linkage rod (4). The middle phalanx linkage rod (5) is rotatably connected to the second position of the fixation frame (1); The driven gear assembly (6) is rotatably connected between the proximal phalanx drive rod (2) and the middle phalanx linkage rod (5), and meshes with the first directional tooth (11); The middle phalanx drive rod (7) is rotatably connected between the proximal phalanx drive rod (2) and the middle phalanx linkage rod (5), and is provided with a third directional tooth (71), which meshes with the driven gear assembly (6); The distal phalanx swing rod (8) is rotatably connected between the distal phalanx linkage rod (4) and the middle phalanx drive rod (7), and is provided with a fourth directional tooth (81), which meshes with the second directional tooth (22).
2. The humanoid robot mechanical finger according to claim 1, characterized in that: The driven gear assembly (6) includes a first driven gear (61) and a second driven gear (62) that mesh with each other. The first driven gear (61) meshes with a first directional tooth (11), and the second driven gear (62) meshes with a third directional tooth (71).
3. The humanoid robot mechanical finger according to claim 2, characterized in that: The first directional tooth (11), the first driven gear (61), the second driven gear (62), and the third directional tooth (71) have the same width and are aligned in a straight line.
4. The humanoid robot mechanical finger according to claim 1, characterized in that: The proximal phalanx drive rod (2) and the middle phalanx linkage rod (5) are connected by the same first fixed shaft (91); A second fixed shaft (92) is provided through the middle phalanx drive rod (7), and the two ends of the second fixed shaft (92) extend to the proximal phalanx drive rod (2) and the middle phalanx linkage rod (5), respectively. A third fixed shaft (93) is provided in the distal phalanx swing rod (8), and the two ends of the third fixed shaft (93) extend to the middle phalanx drive rod (7) and the distal phalanx linkage rod (4), respectively. At least one fourth fixed shaft (94) is provided in the driven gear assembly (6), and the two ends of the fourth fixed shaft (94) extend to the proximal phalanx drive rod (2) and the middle phalanx linkage rod (5).
5. The humanoid robot mechanical finger according to claim 1, characterized in that: A pressure sensor is provided at the end of the distal phalanx swing rod (8).