Compliance-perception integrated fingertip and robot dexterous hand

Abstract

The invention provides a compliance-perception integrated fingertip and a robot dexterous hand, the compliance-perception integrated fingertip comprises a proximal section rack, a middle section phalanx connecting rod and a rigid fingertip, and the proximal section rack, the middle section phalanx connecting rod and the rigid fingertip are hinged and connected in series to form a rigid connecting rod; the continuous elastic plate and the middle phalanx connecting rod are arranged in a crossed mode, and a plurality of flexible strain sensors are distributed on the surface of the continuous elastic plate. According to the compliance-perception integrated fingertip and the robot dexterous hand, a rigid and elastic mixed plane four-bar mechanism structure is adopted, the driver module drives the elastic plate to drive the four-bar mechanism to move, when no load exists, the fingertip and the finger middle joint can be linked according to a specific transmission proportion, and the movement mode of human fingers is simulated; when loaded, the elastic plate provides passive compliance to adapt to a contact posture, and meanwhile, the strain sensor realizes contact force sensing by detecting deformation of the elastic plate, so that motion transmission, passive compliance and force sensing functions are integrated.

Description

Technical Field

[0001] This invention relates to the field of robotic dexterity hand technology, and more particularly to an accommodative-sensory integrated fingertip and robotic dexterity hand. Background Technology

[0002] Dexterous hands are the core end effectors of humanoid robots, widely used in intelligent manufacturing, precision manipulation, and human-robot interaction. Currently, dexterous hands driven by rigid links have become one of the mainstream solutions due to their advantages of structural stability, precise transmission, and ease of modeling and control. However, when faced with uncertain environments or sudden impacts, such purely rigid mechanisms rely entirely on active control algorithms for force and position adjustments, which limits their response speed and safety, making it difficult to provide reliable passive compliant protection.

[0003] To improve the safety and adaptability of interactions, existing technical solutions are mainly divided into two categories: one is to add force / torque sensors to the outside of rigid mechanisms and achieve compliance through active control; the other is to adopt fully flexible or soft structures and utilize the deformation capacity of the materials themselves.

[0004] However, the aforementioned existing technologies have the following drawbacks: the former usually results in complex structures, bulky sizes, and high costs, and sensor drift may pose safety hazards; the latter generally suffers from complex control models, low motion accuracy, and fatigue after long-term use.

[0005] Therefore, in order to solve the above problems, this invention proposes an compliant-sensing integrated fingertip and robot dexterity hand that can achieve a high degree of integration of driving, passive compliance and force sensing at the mechanics level, in order to maintain the high precision and reliable transmission characteristics of rigid mechanisms while possessing safe compliance and force sensing capabilities. Summary of the Invention

[0006] To address the shortcomings of existing robotic dexterous hands, such as the poor passive compliance of rigid finger mechanisms, the reliance on external sensors for force perception leading to structural complexity, and the difficulty and insufficient precision in controlling fully flexible fingers, this invention provides an integrated compliant-sensing fingertip and robotic dexterous hand.

[0007] According to one objective of the present invention, the present invention provides an accommodative-sensory integrated fingertip, comprising:

[0008] A proximal frame is connected to a middle phalanx link via a revolute joint, and the middle phalanx link is connected to a rigid fingertip via a revolute joint.

[0009] Also includes:

[0010] A continuous elastic plate is connected at both ends to the proximal phalanx frame and the rigid fingertip respectively via a revolute joint, and is arranged in a cross manner on the opposite side of the middle phalanx link. The proximal phalanx frame, the middle phalanx link, the rigid fingertip and the continuous elastic plate form a rigid-elastic hybrid antiparallelogram four-bar linkage. The elastic plate is bent in a way that avoids the singular configuration of the mechanism.

[0011] One end of the elastic plate is provided with a drive component, which is configured to drive the elastic plate to rotate around the hinge connecting it to the near section frame, thereby driving the entire four-bar linkage to move.

[0012] A flexible strain sensor is provided on the elastic plate. The flexible strain sensor is configured to detect the deformation of the elastic plate and calculate contact information based on a strain-load sensing algorithm. The drive component can realize active compliant control of the fingertip through the contact information.

[0013] Preferably, the rigid-elastic hybrid antiparallelogram four-bar linkage is configured as follows:

[0014] When the rigid fingertip is not subjected to external load, the elastic plate participates in the movement as a rigid link, realizing the bionic phalanx linkage between the middle phalanx link and the rigid fingertip;

[0015] When the rigid fingertip is subjected to an external load, the elastic plate bends and deforms, causing the rigid fingertip to rotate additionally about the hinge point with the middle phalanx link in accordance with the load.

[0016] Preferably, the driving component includes:

[0017] A connecting terminal is disposed at one end of the elastic plate, which is used to receive external drive and directly drive the elastic plate to rotate around the connecting hinge between it and the near section frame, thereby driving the entire four-bar linkage to move.

[0018] Preferably, the driving component further includes:

[0019] A driver module is connected to the connection terminal. When the rigid fingertip is loaded, the load forces the elastic plate to produce elastic deformation. The flexible strain sensor detects the deformation and calculates contact information based on a strain-load sensing algorithm. The driver module is configured to drive the driver module connection terminal based on the contact information to form active compliance control of the fingertip.

[0020] Preferably, the flexible strain sensor is electrically connected to an external processor, and the processor controls the connection to the driver module;

[0021] When the rigid fingertip is subjected to an external contact load, the flexible strain sensor detects the deformation distribution of the elastic plate in real time. The processor calculates the magnitude, direction and contact point location information of the contact force on the rigid fingertip based on the strain-load sensing algorithm, and controls the driver module to drive the elastic plate through the connection terminal to realize the active compliant control of the rigid fingertip in the four-bar linkage.

[0022] A robotic dexterous hand is also provided, including at least one of the aforementioned compliant-sensory integrated fingertips.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This adaptive-sensing integrated fingertip utilizes a single elastic plate to simultaneously achieve three major functions: force / motion transmission, passive adaptation under load, and contact force sensing. It eliminates the need for external sensors and their complex wiring, greatly improving the compactness and reliability of the fingertip structure.

[0025] This compliant-sensory integrated fingertip adopts a rigid-elastic hybrid antiparallelogram mechanism, which can reproduce the natural finger joint linkage of the human hand when unloaded, and provides inherent passive compliance through the bending deformation of the elastic plate when loaded, greatly improving the inherent safety of human-computer interaction.

[0026] This compliant-sensing integrated fingertip system uses force sensing signals directly derived from the deformation of the elastic plate, a core component of the transmission chain. Its mechanical relationship is clear, calibration is simple, and the sensing signal forms an internal closed loop with the drive control, enabling high-bandwidth force-position hybrid control with rapid response.

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a three-dimensional schematic diagram of an integrated compliant-sensory fingertip as described in this invention;

[0029] Figure 2 This is a frontal view of the compliant-sensory integrated fingertip assembly described in this invention;

[0030] Figure 3 This is a schematic diagram of one embodiment of the compliant-sensory integrated fingertip driving component described in this invention;

[0031] Figure 4 This is a schematic diagram of another embodiment of the compliant-sensory integrated fingertip driving component described in this invention. Detailed Implementation

[0032] The following description is intended to provide a detailed account of the invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0033] This invention provides an integrated compliant-sensing fingertip, the core of which lies in employing a unique rigid-elastic hybrid anti-parallelogram four-bar linkage, and innovatively using a single continuous elastic plate 300 simultaneously as a transmission link, a passive compliant element, and a force-sensing carrier. For a general overview, see [link to related documentation]. Figure 1-4 This compliant-sensory integrated fingertip includes:

[0034] The proximal frame 100 serves as the fixed base for the fingertip mechanism;

[0035] The middle phalanx connecting rod 200 has one end connected to the proximal phalanx frame 100 via a first revolute joint;

[0036] A rigid fingertip 500, one end of which is connected to the other end of the middle phalanx connecting rod 200 via a second revolute joint;

[0037] A continuous elastic plate 300, which is the only elastic element in the mechanism, is arranged in a cross manner on the opposite side of the middle phalanx link 200; the first end of the elastic plate 300 is connected to the proximal frame 100 through a third revolute joint, and the second end is connected to the rigid fingertip 500 through a fourth revolute joint, thereby forming a rigid-elastic hybrid antiparallelogram four-bar linkage together with the middle phalanx link 200 and the proximal frame 100.

[0038] The elastic plate 300 has a non-linear initial bending configuration to avoid the singular motion configuration of the mechanism and ensure that it produces stable and controllable elastic deformation under load.

[0039] The elastic plate 300 is provided with a connection terminal 400 at the first end or near the first end for receiving the output of the external driver module 600 to directly drive the elastic plate 300 to rotate around the axis of the third rotating joint, thereby driving the entire four-bar linkage to move.

[0040] The surface of the elastic plate 300 is integrated with multiple flexible strain sensors, which are electrically connected to an external processor.

[0041] The agency is configured to operate in two modes:

[0042] Free transmission mode: When the rigid fingertip 500 is not subjected to external load, the elastic plate 300 participates in the movement as a rigid link. The driver module 600 drives the elastic plate 300 to make the entire mechanism move like a rigid four-bar linkage, realizing a specific, human-like finger joint linkage between the middle phalanx link 200 and the rigid fingertip 500.

[0043] Passive Compliance-Sensing Mode: When the rigid fingertip 500 is subjected to an external contact load, the load will force the elastic plate 300 to undergo controllable bending deformation around its own axis, thereby breaking the rigid transmission chain and providing the rigid fingertip 500 with an additional degree of freedom, enabling it to passively adjust its posture in accordance with the external load; at the same time, the flexible strain sensor detects the deformation distribution of the elastic plate 300 in real time, and based on the pre-established strain-load mapping relationship (strain-load sensing algorithm), the processor calculates the magnitude, direction and contact point position information of the contact force on the rigid fingertip 500, and uses it to realize the active compliance control of the fingertip.

[0044] For details, please refer to Figure 1 and Figure 2 This embodiment provides an compliant-sensing integrated fingertip driven by a rigid-elastic hybrid four-bar linkage.

[0045] The fingertip is mainly composed of a proximal phalanx frame 100, a middle phalanx link 200, a continuous elastic plate 300, and a rigid fingertip 500, which are connected in series via four revolute joints. The proximal phalanx frame 100 serves as a fixed base, with one end connected to one end of the middle phalanx link 200 via a first revolute joint, and the other end connected to one end of the elastic plate 300 via a second revolute joint. The other end of the middle phalanx link 200 is connected to the proximal end of the rigid fingertip 500 via a third revolute joint. The other end of the elastic plate 300 is connected to the distal end of the rigid fingertip 500 via a fourth revolute joint. Thus, the middle phalanx link 200 and the elastic plate 300 are arranged in a cross configuration in space, forming an anti-parallelogram four-bar linkage together with the proximal phalanx frame 100 and the rigid fingertip 500.

[0046] The core innovation of this invention lies in the fact that the continuous elastic plate 300 in the mechanism is designed as an integrated component that simultaneously undertakes the triple functions of transmission, passive compliance and force sensing.

[0047] The elastic plate 300 is preferably made of a metal or composite material (such as spring steel, titanium alloy, or glass fiber reinforced composite material) with high fatigue strength, good elasticity, and excellent stress-strain linearity. Figure 1 and Figure 2As shown, its initial form is a non-linear bending configuration. The core purpose of this specific configuration is to avoid the singular motion configuration that may occur in traditional linear linkages from a mechanistic perspective, thereby ensuring smooth transmission throughout the entire range of motion and laying the geometric foundation for stable, controllable, and easily decoupled elastic bending deformation under subsequent loads.

[0048] A connection terminal 400 is integrally formed or fixedly connected to the elastic plate 300 near its hinge point with the proximal frame 100, i.e., at the position of the second rotary joint. This terminal 400 is used to connect to the output terminal of an external driver module 600. Optionally, the driver module 600 is as follows: Figure 3 The linear electric cylinder shown, or, as... Figure 4 The rotary motor shown is an example. During operation, the driver module 600 acts directly on the terminal 400, driving the elastic plate 300 to rotate around its hinge axis with the proximal frame 100. This drive input is transmitted through the elastic plate 300, thereby driving the entire rigid-elastic hybrid four-bar linkage to move, ultimately realizing the flexion and extension movement of the rigid fingertip 500.

[0049] Flexible strain sensors can be selected from flexible strain gauges based on metal foil or semiconductor materials, or printed flexible sensing circuits, etc. Multiple flexible strain sensors are attached to key areas on the surface of the elastic plate 300 in an optimized topological layout. These areas are determined based on finite element simulation, specifically by selecting locations on the plate where the strain gradient is significant under the expected load or where the load is sensitive. All flexible strain sensors are electrically connected to an external processor or control unit.

[0050] Working principle and process:

[0051] The fingertip has two inherently coupled operating states, which are switched by whether the rigid fingertip 500 is subjected to an external contact load:

[0052] 1. Free transmission state (no external load):

[0053] In this state, the actuator module 600 drives the elastic plate 300 to rotate via the terminal 400. Since the rigid fingertip 500 is not in contact with any external object, the mechanism is not subjected to external loads, and the elastic plate 300 participates in the movement only as an effective "rigid link." At this time, the entire mechanism behaves as a standard, rigid anti-parallelogram four-bar linkage with defined motion relationships. The rigid fingertip 500 and the middle phalanx link 200 will follow the unique kinematic laws of this mechanism, moving in a specific, non-linear transmission ratio. This motion mode can well simulate the natural flexion and extension relationship between human finger joints.

[0054] 2. Passive compliance and force-sensing state (under external load):

[0055] When the rigid fingertip 500 comes into contact with an object and is subjected to an external load, the contact force is transmitted to the four-bar linkage through the rigid fingertip 500. In this situation, the continuous elastic plate 300, as the only elastic element in the mechanism, undergoes controlled bending deformation. This deformation process achieves two key functions:

[0056] a) Passive compliance: The deformation of the elastic plate 300 essentially provides the system with an additional, passive degree of freedom. It "absorbs" part of the motion displacement caused by the conflict between the input of the driver module 600 and external constraints, so that the rigid fingertip 500 can deviate relative to the trajectory preset by the pure rigid transmission, thereby passively conforming to the geometry of the object surface or offsetting part of the impact, providing inherent safety.

[0057] b) Real-time force sensing: The bending deformation of the elastic plate 300 is detected in real-time and distributedly by a flexible strain sensor array integrated on its surface. The strain signals output by the sensors are transmitted to the processor. The processor contains a strain-load mapping database calibrated through experimental or computational mechanical models (i.e., a strain-load sensing algorithm). By solving the real-time signals from the sensor array, the algorithm can reconstruct the magnitude of the contact force acting on the rigid fingertip 500 and further estimate the position of the contact point. This sensing information can be fed back to the control system of the actuator module 600.

[0058] c) Implementation of control closed loop:

[0059] The calculated real-time contact force information can be immediately used to construct a high-bandwidth force-position hybrid control closed loop. For example, the control system can precisely adjust the output of the actuator module 600 based on the sensed contact force to achieve constant force gripping; or when a sudden impact force exceeds the safety threshold, it can quickly instruct the actuator module 600 to perform protective actions (such as rapid retraction or force relief). Thus, through the mechanical behavior of a single elastic plate 300, full-function integration from drive input, motion transmission, passive safety compliance to high-bandwidth force sensing is achieved.

[0060] Please see Figure 3 Based on the aforementioned accommodative-sensory integrated fingertip, this invention also provides a modular robotic finger. This finger includes all the components of the aforementioned accommodative-sensory integrated fingertip, and further includes a proximal finger mechanism and a actuator module 600. The proximal finger mechanism can be considered as the connection and drive transmission segment between the palm and the fingertip. The connection terminal 400 can be connected to proximal finger transmission links of different specifications or functions. This modular design allows the accommodative and sensing fingertip to be flexibly adapted to various existing robotic dexterous hand platforms, or used to construct novel multi-fingered hand systems.

[0061] The present invention also provides a robotic dexterous hand, including at least one of the aforementioned accommodative-sensory integrated fingertips, wherein the connection terminal 400 is configured to be embedded in the proximal joint drive link of the robotic dexterous hand, and the accommodative-sensory integrated fingertips are configured to be interconnected or to mount circuit elements.

[0062] In summary, this compliant-sensory integrated fingertip adopts a planar cross four-bar linkage consisting of rigid and elastic links. The elastic link is composed of an elastic plate 300, and the rigid link is composed of a middle rigid finger bone 200. The connection between the two links is a revolute joint.

[0063] The actuator module 600 drives the rigid-elastic hybrid planar cross four-bar linkage through the elastic plate 300, which can realize the flexion and extension movement of the robot's fingers and the compliant grasping of objects. By arranging sensors on the elastic plate 300, the sensor can perceive the fingertip contact force, contact position and finger flexion and extension state in real time when the finger conforms to the shape of the interactive object, and actively control the grasping force of the finger to adapt to different operation requirements, thereby realizing the control of the finger flexion and extension configuration and contact force.

[0064] This integrated compliant-sensory fingertip is simple to manufacture and easy to assemble, meeting the needs of experiments and operations in the field of robotic dexterity.

[0065] The embodiments described above are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The scope of patent application of the present invention should not be limited by these embodiments. That is, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention still fall within the patent scope of the present invention.

Claims

1. An adaptive-sensory integrated fingertip, comprising: A proximal frame (100) is connected to a middle phalanx link (200) via a revolute joint, and the middle phalanx link (200) and a rigid fingertip (500) are connected via a revolute joint. Its characteristic is that it further includes: A continuous elastic plate (300) is connected at both ends to the proximal phalanx frame (100) and the rigid fingertip (500) respectively via a revolute joint, and is arranged in a cross manner on the opposite side of the middle phalanx link (200). The proximal phalanx frame (100), the middle phalanx link (200), the rigid fingertip (500) and the continuous elastic plate (300) form a rigid-elastic hybrid anti-parallelogram four-bar linkage. The elastic plate (300) is bent in a way that avoids the singular configuration of the mechanism. One end of the elastic plate (300) is provided with a driving component, which is configured to drive the elastic plate (300) to rotate around the hinge connecting it to the near section frame (100), thereby driving the entire four-bar linkage to move. A flexible strain sensor (500) is provided on the elastic plate (300). The flexible strain sensor (500) is configured to detect the deformation of the elastic plate (300) and calculate contact information based on a strain-load sensing algorithm. The drive component can realize active compliant control of the fingertip through the contact information.

2. The compliant-sensory integrated fingertip according to claim 1, characterized in that, The rigid-elastic hybrid antiparallelogram four-bar linkage is configured as follows: When the rigid fingertip (500) is not subjected to external load, the elastic plate (300) participates in the movement as a rigid link, realizing the bionic phalanx linkage between the middle phalanx link (200) and the rigid fingertip (500); When the rigid fingertip (500) is subjected to an external load, the elastic plate (300) bends and deforms, causing the rigid fingertip (500) to rotate additionally in accordance with the load about its hinge point with the middle phalanx link (200).

3. The compliant-sensory integrated fingertip according to claim 1, characterized in that, The driving component includes: A connecting terminal (400) is disposed at one end of the elastic plate (300) for receiving external drive and directly driving the elastic plate (300) to rotate around its connecting hinge with the near-section frame (100), thereby driving the entire four-bar linkage to move.

4. The compliant-sensory integrated fingertip according to claim 3, characterized in that, The connecting terminal (400) drives the elastic plate (300) via a linkage or direct drive.

5. The compliant-sensory integrated fingertip according to claim 3, characterized in that, The driving component also includes: A driver module (600) is connected to the connection terminal (400). When the rigid fingertip (500) is loaded, the load forces the elastic plate (300) to produce elastic deformation. The flexible strain sensor (500) detects the deformation and calculates the contact information based on the strain-load sensing algorithm. The driver module (600) is configured to drive the connection terminal (400) based on the contact information to form active compliance control of the fingertip.

6. The compliant-sensory integrated fingertip according to claim 5, characterized in that, The driver module (600) is either a linear driver module (600) or a rotary driver module (600).

7. The compliant-sensory integrated fingertip according to claim 5, characterized in that, The flexible strain sensor is electrically connected to an external processor, and the processor controls the connection to the driver module (600). When the rigid fingertip (500) is subjected to an external contact load, the flexible strain sensor detects the deformation distribution of the elastic plate (300) in real time. The processor calculates the magnitude, direction and contact point position information of the contact force on the rigid fingertip (500) based on the strain-load sensing algorithm, and controls the driver module (600) to drive the elastic plate (300) through the connection terminal (400) to realize the active compliant control of the rigid fingertip (500) in the four-bar linkage.

8. The compliant-sensory integrated fingertip according to claim 1, characterized in that, The elastic plate (300) integrates multiple flexible strain sensors (500), enabling the elastic plate (300) to simultaneously serve as a transmission link, a passive compliant element, and a force sensing carrier.

9. The accommodative-sensory integrated fingertip according to claim 1, characterized in that, The flexible strain sensor (500) is arranged on the elastic plate (300) to predict areas with large strain, and is used to optimize the sensing accuracy and decoupling capability of force and torque.

10. A robotic dexterous hand, characterized in that, Including at least one compliant-sensory integrated fingertip as described in any one of claims 1-9.

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