Electrically actuated flexible driven bionic wrist, bionic robot

Abstract

The application provides an electrically actuated flexible driving bionic wrist and a bionic robot, comprising a bionic carpal bone skeleton system, a proximal end bionic skeleton member and a distal end bionic skeleton member, the proximal end bionic skeleton member is movably connected with the distal end bionic skeleton member through a bionic wrist joint, forming a multi-degree-of-freedom wrist joint complex; further comprising a plurality of independent flexible driving units and a bionic tendon transmission system, a bionic tendon sheath and a pulley system. The electrically actuated flexible driving bionic wrist and the bionic robot provided by the application realize the unification of multi-degree-of-freedom motion and essential flexibility by adopting a plurality of bionic joints connected by bionic soft tissues and a plurality of independent driving units, effectively solve the problems of limited movement range, lack of flexible adaptation mechanism and insufficient dynamic buffering capacity of traditional rigid wrist mechanisms, have multi-degree-of-freedom motion capability, essential flexibility and wide-range motion capability, can adapt to complex operation environments and provide effective buffering.

Description

Technical Field

[0001] This application relates to the field of bionic robot technology, specifically to an electrically actuated flexible-drive bionic wrist and a bionic robot. Background Technology

[0002] Current bionic wrist designs for robots aim to integrate multi-degree-of-freedom motion capabilities and inherent compliance within a limited volume. However, existing robotic wrists are generally constrained by rigid, interconnected structures, limiting the physical range of motion of the joints and lacking compliant adaptability in unstructured environments, thus restricting operational space. Faced with increasingly complex operational scenarios, developing novel wrist mechanisms with bionic appearance, compact configuration, and full-pose reachability is a crucial approach to solving the current challenges of dexterous robotic manipulation. Summary of the Invention

[0003] The purpose of this application is to provide an electrically actuated flexible drive bionic wrist and a bionic robot, which has multi-degree-of-freedom motion capabilities, inherent compliance and wide-range motion capabilities, and can adapt to complex operating environments.

[0004] This application provides an electrically actuated flexible bionic wrist, the technical solution of which is as follows:

[0005] A bionic wrist bone system includes a proximal bionic bone component and a distal bionic bone component. The proximal and distal bionic bone components are connected by a bionic wrist joint to form a multi-degree-of-freedom wrist joint complex with flexion-extension, radial and ulnar deviation, and pronation and supination degrees of freedom.

[0006] Multiple independent flexible drive units, including at least the following drive groups:

[0007] Wrist flexion drive assembly, used to provide palmar flexion power to the wrist joint;

[0008] Wrist extension drive assembly, used to provide wrist dorsiflexion power;

[0009] The radial deviation drive group is used to provide radial deviation swing force for the wrist joint;

[0010] Ulnar deviation drive assembly, used to provide ulnar deviation swing force for the wrist joint;

[0011] Pronation drive assembly, used to provide forearm pronation power;

[0012] Supination drive assembly, used to provide forearm supination power;

[0013] The flexible drive unit is composed of an electro-actuated functional component, which includes a solid electro-actuated material or an electro-hydraulic conversion unit. The electro-actuated functional component is capable of active deformation under electric field excitation, and its deformation behavior under electric field excitation is at least anisotropic. The wrist flexion drive group and the wrist extension drive group are arranged in antagonistic arrangement, the radial deviation drive group and the ulnar deviation drive group are arranged in antagonistic arrangement, and the pronation drive group and the supination drive group are arranged in antagonistic arrangement.

[0014] The bionic tendon cable transmission system includes multiple bionic tendons. One end of each bionic tendon cable is fixedly connected to the output end of the corresponding flexible drive unit, and the other end is connected to the proximal or distal bionic bone component through a bionic attachment point, so as to transmit the driving force to the multi-degree-of-freedom wrist joint complex through the bionic tendon cable.

[0015] A bionic tendon sheath and trochlear system includes multiple bionic tendon sheath and trochlear structures disposed on the proximal and distal bionic bone components for constraining and guiding the movement path of the bionic tendon chordae.

[0016] According to one embodiment of this application, the electrostatic hydraulic conversion unit generates internal pressure by applying an electric field to an insulating fluid, thereby driving the flexible packaging structure to undergo local buckling to achieve deformation output.

[0017] According to one embodiment of this application, the proximal bionic skeletal component includes a bionic distal radius and a bionic distal ulna, and the distal bionic skeletal component includes at least one bionic carpal bone; the bionic distal radius and the bionic distal ulna are movably connected by a bionic distal radioulnar joint, and the bionic carpal bone is movably connected to the bionic distal radius, the bionic distal ulna, and the hand skeletal component, respectively.

[0018] According to one embodiment of this application, the biomimetic distal radioulnar joint includes a biomimetic triangular fibrocartilage complex; the biomimetic triangular fibrocartilage complex is made of a flexible elastomer material, with its proximal end fixed to the distal end of the biomimetic ulna and its distal end attached to the ulnar notch of the distal end of the biomimetic radius; the biomimetic triangular fibrocartilage complex is used to provide elastic restraint and axial cushioning during wrist joint rotation and lateral swing, and to maintain the stability of the distal radioulnar joint.

[0019] According to one embodiment of this application, the bionic tendon cables of the pronation drive group and the supination drive group are arranged in a cross-spiral manner on the bionic forearm: wherein, the bionic tendon cables of the pronation drive group originate from the ulnar side of the distal end of the bionic ulna and cross obliquely to the palmar side of the distal end of the bionic radius; the bionic tendon cables of the supination drive group originate from the palmar side of the distal end of the bionic radius and cross obliquely to the dorsal side of the distal end of the bionic ulna; the bionic tendon sheath and trochlear system includes cross-guided trochlears respectively provided on the radius and ulna to limit the radial displacement of the bionic tendon cables during rotation.

[0020] According to one embodiment of this application, the electro-actuated flexible bionic wrist further includes a bionic carpal tunnel structure for receiving and guiding bionic tendineae and neurovascular bundles passing through the wrist joint.

[0021] According to one embodiment of this application, the bionic carpal tunnel is internally divided into multiple independent tendon channels, including flexor tendon channels and neurovascular simulated bundle channels; the flexor tendon channels are lined with a low-friction coating; the neurovascular simulated bundle channels are used to arrange bionic nerves or bionic blood vessels.

[0022] According to one embodiment of this application, the electro-actuated flexible bionic wrist further includes a multimodal wrist sensing system, the multimodal wrist sensing system comprising:

[0023] Capacitive or resistive pressure sensors are placed between the distal end of the bionic radius and the bionic lunate to detect axial loads on the wrist joint.

[0024] Angle sensors, respectively installed at the distal radioulnar joint and the radiocarpal joint, are used to detect the wrist flexion-extension angle, radial / ulnar deviation angle, and forearm pronation / supination angle.

[0025] The tendon tension sensor, installed inside the bionic carpal tunnel, is used to monitor the tendon tension of each drive unit in real time.

[0026] The angle sensor and tension sensor, together with the flexible drive unit, form a closed-loop control circuit to achieve coordinated control and impedance regulation of antagonistic muscle groups in compound motion.

[0027] According to one embodiment of this application, the closed-loop control circuit includes:

[0028] The adaptive impedance adjustment module is configured to calculate the joint spatial pose deviation based on the actual joint angle fed back by the angle sensor, and adjust the pulse parameter combination of the pulse drive signal applied to each flexible drive unit in real time according to the rate of change and direction of the pose deviation, so as to achieve adaptive adjustment of joint impedance.

[0029] The pulse parameter combination includes at least the pulse bias level, pulse amplitude, pulse duty cycle, and pulse frequency.

[0030] According to one embodiment of this application, the closed-loop control circuit further includes:

[0031] The force and displacement coordination distribution module is configured to receive the actual tendon tension of each flexible drive unit fed back by the tendon tension sensor, and calculate the target pulse duty cycle and target pulse amplitude required by each flexible drive unit according to the preset desired deformation ratio and the stiffness and damping adjustment amount output by the adaptive impedance adjustment module.

[0032] The target pulse duty cycle and the target pulse amplitude together determine the matching relationship between the desired deformation and the desired output force of each flexible drive unit.

[0033] The force and displacement coordination distribution module also allocates complementary pulse duty cycles to different flexible drive units in the same antagonistic pair according to the coordinated coupling relationship between the drive groups arranged in each antagonistic arrangement, so that both sides of the antagonistic pair maintain active tension within the preset neighborhood of the joint balance position, so as to achieve zero-position stiffness and anti-disturbance capability of the joint.

[0034] According to one embodiment of this application, the electrically actuated flexible drive bionic wrist further includes a bionic wrist joint capsule, which is made of a flexible sealing material and covers the outside of the bionic distal radius joint, the bionic intercarpal joint, and the bionic carpal metacarpophalangeal joint; the bionic wrist joint capsule is filled with a lubricating medium.

[0035] This application also proposes a bionic robot, including any of the above-mentioned electrically actuated flexible-drive bionic wrists.

[0036] The above-mentioned one or more technical solutions in the embodiments of this application have at least one of the following technical effects: by adopting multiple bionic joints and multiple independent drive units connected by bionic soft tissue, the unity of multi-degree-of-freedom motion and inherent compliance is achieved, which effectively solves the problems of limited range of motion, lack of compliance adaptation mechanism and insufficient dynamic buffering capacity of traditional rigid wrist mechanisms. It has multi-degree-of-freedom motion capability, inherent compliance and wide range of motion capability, and can adapt to complex operating environments and provide effective buffering. Attached Figure Description

[0037] Figure 1 A schematic diagram illustrating the radial and ulnar directions of an electrically actuated flexible bionic wrist according to an embodiment of this application;

[0038] Figure 2 This is a schematic diagram illustrating the direction of flexion and extension movements of an electrically actuated flexible bionic wrist according to one embodiment of this application.

[0039] Figure 3 A schematic diagram illustrating the direction of pronation motion of an electrically actuated flexible bionic wrist according to an embodiment of this application;

[0040] Figure 4An exploded view of an embodiment of the electrically actuated flexible bionic wrist provided in this application;

[0041] Figure 5 This is a schematic diagram of the structure of an electrically actuated flexible bionic wrist provided in one embodiment of this application.

[0042] Figure labeling: 1. Proximal bionic skeletal component; 2. Distal bionic skeletal component; 3. Bionic wrist joint; 4. Flexible drive unit; 5. Bionic tendon cable transmission system; 6. Bionic tendon sheath and trochlear system; 11. Bionic distal radius; 12. Bionic distal ulna; 7. Bionic carpal tunnel structure. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are only used to illustrate this application and are not intended to limit the scope of protection of this application.

[0044] For ease of understanding, the following explains some key terms in this embodiment:

[0045] An electro-actuated flexible bionic wrist is a mechanical device that simulates the structure and movement function of the human wrist joint, aiming to achieve multi-degree-of-freedom and highly compliant movement.

[0046] Bionic soft tissue refers to flexible materials used to connect bionic joints. Its function is to provide passive compliance and cushioning between joints, and it can simulate the function of ligaments and joint capsules in living organisms.

[0047] Bionic joints are the basic units that make up the kinetic chain of an electrically actuated flexible bionic wrist. They are interconnected through bionic soft tissues to achieve complex wrist movements.

[0048] The bionic distal radius joint refers to the joint in the bionic wrist that simulates the connection between the distal radius and the carpal bones in the human body. It is mainly responsible for the flexion, extension, and some lateral movements of the wrist.

[0049] The bionic wrist joint refers to the joint in the bionic wrist that simulates the connection between the wrist bones in the human body and is mainly responsible for the lateral movement of the wrist.

[0050] Bionic wrist-metacarpal joints refer to the joints in an electrically actuated, flexibly driven bionic wrist that simulate the connection between the wrist bones and metacarpal bones in the human body, providing further degrees of freedom of movement for the wrist.

[0051] An elliptic joint is a joint whose joint contact surface is elliptical in shape. Its geometric characteristics allow rotational movement in two principal axes while restricting rotation in a third direction, thereby achieving specific movement patterns.

[0052] The drive unit is an independent module that provides motion power for the electrically actuated flexible drive bionic wrist. It transmits power to the bionic joint through bionic tendineae.

[0053] Bionic tendon chords are flexible components that mimic the function of tendons in living organisms. One end is connected to a drive unit, and the other end is connected to a bionic bone structure. They drive the bionic joint by stretching or relaxing.

[0054] Traditional robotic arm wrist mechanisms, due to their rigid serial structure, suffer from limited joint range of motion and lack compliant adaptability in unstructured environments, thus restricting operational space and dexterity. This makes it difficult for existing technologies to meet the demands of increasingly complex work scenarios for full-pose reachability of robots.

[0055] In this regard, the purpose of this application is to provide an electrically actuated flexible drive bionic wrist and bionic robot, which has multi-degree-of-freedom motion capability, inherent compliance and wide range of motion capability, and can adapt to complex operating environments.

[0056] Figure 1 In one embodiment, 'a' represents the stationary state of the electrically actuated flexible bionic wrist. Figure 1 In the figure, 'b' represents the shape of the radial lateral movement of the electrically actuated flexible bionic wrist. Figure 1 In the middle, 'c' represents the ulnar deviation motion of the electrically actuated flexible bionic wrist.

[0057] Figure 2 The d-direction represents the extension movement of the electro-actuated flexible bionic wrist, and the e-direction represents the flexion movement of the electro-actuated flexible bionic wrist.

[0058] Figure 3 In the figure, the direction f is the direction of pronation of an electrically actuated flexible bionic wrist in one embodiment; the direction of supination is opposite to the direction f and is not shown in the figure.

[0059] like Figures 4 to 5 As shown, this application provides an electrically actuated flexible bionic wrist, the technical solution of which is as follows:

[0060] A biomimetic wrist bone system includes a proximal biomimetic bone component 1 and a distal biomimetic bone component 2. The proximal and distal biomimetic bone components 1 and 2 are movably connected via a biomimetic wrist joint 3, forming a multi-degree-of-freedom wrist joint complex with flexion-extension, radial and ulnar deviation, and pronation and supination degrees of freedom. Multiple independent flexible actuation units 4 include at least the following actuation groups: a wrist flexion actuation group for providing palmar flexion power; a wrist extension actuation group for providing dorsiflexion power; a radial deviation actuation group for providing radial deviation swinging force; an ulnar deviation actuation group for providing ulnar deviation swinging force; a pronation actuation group for providing forearm pronation power; and a supination actuation group for providing forearm supination power. Each flexible actuation unit 4 is composed of an electro-actuated functional component, which includes a solid electro-actuated material or an electrostatic fluid. The pressure conversion unit and the electro-actuated functional component are capable of active deformation under electric field excitation, and their deformation behavior under electric field excitation is at least anisotropic. The wrist flexion drive group and the wrist extension drive group are arranged in an antagonistic manner, the radial deviation drive group and the ulnar deviation drive group are arranged in an antagonistic manner, and the pronation drive group and the supination drive group are arranged in an antagonistic manner. The bionic tendon cable transmission system 5 includes multiple bionic tendons, one end of each bionic tendon cable is fixedly connected to the output end of the corresponding flexible drive unit 4, and the other end is connected to the proximal bionic bone component 1 or the distal bionic bone component 2 through a bionic attachment point, so as to transmit the driving force to the multi-degree-of-freedom wrist joint complex through the bionic tendons. The bionic tendon sheath and pulley system 6 includes multiple bionic tendon sheath and pulley structures disposed on the proximal bionic bone component 1 and the distal bionic bone component 2, which are used to constrain and guide the movement path of the bionic tendons.

[0061] In one embodiment, the electro-actuated functional component is a solid electro-actuated material. Exemplarily, this solid electro-actuated material can be a dielectric elastomer actuator (DEA), which includes a dielectric layer and flexible electrode layers disposed on both sides of the dielectric layer; the dielectric layer is made of an elastomer material, and the flexible electrode layers can deform with the dielectric layer. Under the action of an applied electric field, the dielectric layer undergoes compression in the thickness direction and expansion in the planar direction, thereby generating driving force and displacement. In other embodiments, the solid electro-actuated material can also be an electro-actuated polymer, piezoelectric ceramic, or other materials, as long as they can generate active deformation in a specific direction under electric field excitation. By electrode patterning or material pre-stretching treatment, the deformation direction of the above-mentioned solid electro-actuated material can be made anisotropic, that is, generating effective driving force only along the fiber orientation of biomimetic muscles.

[0062] In another embodiment, the electro-actuated functional component can also be an electro-hydraulic conversion unit. Exemplarily, this electro-hydraulic conversion unit includes a flexible encapsulation structure and an insulating fluid filling the interior of the flexible encapsulation structure. Electrode pairs are disposed in localized areas of the flexible encapsulation structure. When an electric field is applied to the electrode pairs, the electric field acts on the insulating fluid, generating internal pressure. This internal pressure drives local buckling deformation of the flexible encapsulation structure in localized weak zones of the electrode region, thereby converting electrical energy into mechanical deformation output. By adjusting the arrangement of the electrode pairs and the geometry of the flexible encapsulation structure, the direction of this localized buckling deformation can be controlled, enabling the overall deformation output of the electro-hydraulic conversion unit to also exhibit anisotropic characteristics, capable of contraction or extension along a target direction. This electro-hydraulic conversion unit, as an alternative to solid electro-actuated materials, can be selected based on specific application requirements such as load conditions or fatigue life. For example, an electro-hydraulic conversion unit can be used in scenarios requiring high driving force or a large stroke, while a solid electro-actuated material can be used in scenarios requiring high response speed.

[0063] In some embodiments, the insulating fluid may be a high dielectric constant insulating oil with a relative dielectric constant ε≥2.5 at room temperature and a kinematic viscosity ≤50 cSt; the insulating oil is selected from any one or more combinations of mineral-based transformer oil, synthetic ester oil, silicone oil or fluorinated liquid.

[0064] In one implementation, the insulating fluid needs to be selected based on the actuator's operating voltage and target frequency response. Specifically, in high-speed gripping scenarios, low-viscosity (e.g., ≤20 cSt) synthetic ester oil or silicone oil is preferred to reduce flow resistance, while in high-voltage, slow-speed, heavy-load scenarios, mineral-based transformer oil is selected and filled into the flexible cavity through a vacuum degassing and potting process to ensure complete removal of air bubbles to avoid partial discharge breakdown. Simultaneously, the chemical inertness of the fluorinated liquid or synthetic ester protects the inner polymer film from swelling corrosion. Based on this, its beneficial effects are reflected in a two-dimensional synergistic improvement: at the energy conversion level, the constraint of ε≥2.5 is directly based on Maxwell's stress formula (…). This ensures the efficiency of converting electric field energy into hydraulic energy, enabling the actuator to obtain sufficient hydraulic pressure under a typical 3~10 kV drive voltage without blindly increasing the pressure, thus balancing power density and electrical safety. In terms of response speed, the kinematic viscosity ≤50 cSt controls the internal shear friction loss of the liquid to an extremely low level, ensuring that during high-frequency dynamic driving (such as rapid grasping and releasing of a bionic hand, with a frequency ≥10 Hz), the internal pressure wave can be instantly transmitted to the buckling weak zone, without causing response lag or action delay due to excessive viscous damping.

[0065] In some embodiments, the electrode pairs disposed in a local area of ​​the flexible packaging structure can be a stretchable conductive coating coated or printed on the outer wall of the flexible packaging structure; wherein, the stretchable conductive coating is a liquid metal coating or a carbon nanotube / graphene composite conductive paste coating.

[0066] In one embodiment, the stretchable conductive coating employs differentiated processes depending on the material type. Liquid metal coatings (such as eutectic gallium-indium alloys) can be applied to the outer wall of the flexible packaging structure via spraying, scraping, or mask printing to form conformal electrodes. The natural oxide layer on its surface maintains the pattern shape without flowing. Carbon nanotube / graphene composite conductive paste is applied via screen printing or gravure printing, supplemented by low-temperature thermal curing to ensure tight adhesion to the polymer shell. Based on the above, the liquid metal, due to its fluid properties, releases localized stress through flow during buckling deformation, and the carbon nanotube network... The three-dimensional flexible contact maintains the conductive permeation path, and both can stably control the sheet resistance change rate within a certain range (such as within ±20%) when the actuator undergoes a large number of cyclic bucklings. This ensures that the electrode will not develop micro-cracks due to wrinkles and folds, thereby maintaining the uniformity of the driving electric field and the stability of the capacitance self-sensing signal. At the same time, the electrode is directly integrated into the outer wall of the shell by printing or coating processes, avoiding the risk of interface shear strain and detachment introduced by additional adhesive film layers. It also significantly reduces the assembly thickness and weight, meeting the needs of lightweight and highly integrated bionic hands.

[0067] In some embodiments, the flexible drive unit array composed of multiple independent flexible drive units may include the following structural types: a first structural type, a second structural type, and a third structural type; wherein, in the first structural type, all flexible drive units in the array are solid electro-actuated materials; in the second structural type, all flexible drive units in the array are electro-hydraulic conversion units; and in the third structural type, the flexible drive units in the array include both solid electro-actuated materials and electro-hydraulic conversion units.

[0068] In one embodiment, based on the above three structural types, in the bionic wrist of this application, each flexible drive unit is distributed in the corresponding area of ​​the bionic wrist in a six-group antagonistic arrangement: wrist flexion drive group, wrist extension drive group, radial deviation drive group, ulnar deviation drive group, pronation drive group, and supination drive group. The output end of each flexible drive unit is fixedly connected to the corresponding bionic tendon chord. Under the constraint and guidance of the bionic tendon sheath and trochlear system, each bionic tendon chord transmits the driving force to each bone component of the bionic wrist bone system, thereby driving the multi-degree-of-freedom wrist joint complex to perform flexion-extension, radial / ulnar deviation, and pronation / supination movements. In the aforementioned structures, the first structural type (all solid-state electro-actuated materials) utilizes the fast response speed and high control precision of solid-state electro-actuated materials, enabling the bionic wrist to achieve rapid response and precise force output in high-frequency reciprocating motion and precise posture adjustment scenarios. Simultaneously, anisotropic deformation achieved through electrode patterning or pre-stretching ensures efficient transmission of driving force along the target direction of the bionic tendons. The second structural type (all electro-hydraulic conversion units) utilizes the large output force and designable stroke of electro-hydraulic conversion units, enabling the bionic wrist to provide sufficient driving force and range of motion in heavy-duty operations and large-range motion scenarios. Furthermore, anisotropic deformation output achieved through adjusting the arrangement of electrode pairs and the geometric configuration of the flexible encapsulation structure ensures concentrated output of driving force in the target direction. The compressibility of insulating fluids provides the bionic wrist with additional passive compliance and shock absorption capabilities. The third structural type (hybrid configuration) differentiates the selection based on the functional requirements of each drive group in the bionic wrist. For example, in antagonistic pairs such as wrist flexion drive group and wrist extension drive group, which need to bear large loads and impacts, electro-hydraulic conversion units are selected to provide sufficient driving force and shock resistance. In antagonistic pairs such as radial deflection drive group and ulnar deflection drive group, which require fine force adjustment, solid electro-actuated materials are selected to achieve high-precision force control. In antagonistic pairs such as pronation drive group and supination drive group, which require both speed and force output, two types of drive units are mixed according to specific load requirements. This allows for multi-dimensional comprehensive optimization of response speed, output force, energy efficiency, and cost in the same bionic wrist.The three structural types mentioned above, by providing three different array structure types, enable the bionic wrist to flexibly select the most suitable drive unit configuration scheme according to the needs of different application scenarios (such as high-speed precision operation, heavy-load operation, or comprehensive performance optimization), significantly improving the applicability and market adaptability of the bionic wrist. By mixing solid-state electro-actuated materials and electro-hydraulic conversion units (the third structural type) in the same bionic wrist, different drive groups can select the optimal drive element type according to their respective functional characteristics and load conditions. This achieves differentiated configuration of internal resources and optimal performance matching of the bionic wrist. The solid-state electro-actuated materials are responsible for drive tasks requiring fast response and high precision, while the electro-hydraulic conversion units are responsible for drive tasks requiring high output and impact resistance. Thus, the bionic wrist achieves multi-dimensional improvements in response speed, load capacity, energy efficiency, and motion accuracy. The two electro-actuated functional components can achieve anisotropic deformation under electric field excitation, and both achieve efficient force transmission through bionic tendon chords and tendon sheath trolley systems. Therefore, when mixed configurations are made in the same bionic wrist, there is no need to change the overall transmission architecture. Performance switching can be achieved by simply replacing or combining at the drive unit level, which greatly reduces the design and manufacturing costs of the bionic wrist under different performance requirements and enhances the versatility and scalability of the product. The compressibility of the insulating fluid in the electro-hydraulic conversion unit and the low elastic modulus of the solid electro-actuated material itself provide the bionic wrist with a dual source of inherent compliance. This makes the bionic wrist have richer passive compliance mechanisms when subjected to external impacts or performing compliant interactions, effectively protecting the bionic skeleton and tendon chord transmission system from impact damage, and significantly improving the operational safety and service life of the bionic wrist in unstructured environments.

[0069] In some embodiments, under the third structural type described above (i.e., a solid electro-actuated material body (such as dielectric elastomer DEA) and an electro-hydraulic conversion unit (such as Peano-HASEL) are arranged in a mixed manner in the bionic hand), two completely independent high-voltage DC-DC boost modules can be used, one dedicated to the solid electro-actuated material body and the other to the electro-hydraulic conversion unit.

[0070] In one embodiment, a current-limiting pre-charge resistor (the resistance value is selected based on the time constant τ=R·C of its equivalent capacitance, typically tens to hundreds of kiloohms) is connected in series in the branch containing the solid-state electro-actuator to suppress the surge current at the moment of power-on. A large-capacity supercapacitor (hundreds of microfarads) is connected in parallel on the bus side of this branch as an instantaneous energy buffer, ensuring that the solid-state electro-actuator will not pull down the voltage through the shared DC bus when charging with high frequency and high current. The branch containing the electrostatic hydraulic conversion unit does not need to add an energy storage capacitor, and only relies on an independent voltage regulation feedback loop to maintain its set voltage. Based on this physical isolation scheme, on the one hand, the interference of the bus voltage drop caused by the charging and discharging of the solid-state electro-actuator on the output force of the electrostatic hydraulic conversion unit is eliminated, so that the latter can still maintain a stable contraction displacement and tension output during rapid gripping and releasing actions. On the other hand, the combination of the current-limiting resistor and the supercapacitor smoothly absorbs the transient current impact of the solid-state electro-actuator, avoiding the electrical stress damage of the high-voltage module switching tube by the large current, thereby significantly improving the electrical reliability of the two types of actuators working together for a long time.

[0071] In some embodiments, under the third structural type described above, at the control signal scheduling level, a hierarchical heterogeneous control architecture can be adopted to completely decouple the high-speed and low-speed drive loops from the physical bus: the position closed-loop command of the electrostatic hydraulic conversion unit is issued by the main control chip through a low-bandwidth CAN bus (the communication rate is set to 125 kbps, and the control refresh rate is ≤100 Hz), and its control cycle is synchronized with the robot motion planning cycle, avoiding continuous occupation of the bus bandwidth; since the mechanical response bandwidth of the electrostatic hydraulic conversion unit is relatively narrow (usually less than 5 Hz), The control commands of the solid-state electro-actuated material do not require high-frequency refresh; while the high-frequency PWM drive signal of the solid-state electro-actuated material does not go through the digital bus at all, but is directly generated in real time by the onboard analog PID circuit (based on operational amplifier and RC network) located near the actuator. This analog circuit uses the high-frequency triangular wave output by the hardware comparator as the carrier wave, and converts the amplitude command given by the main control chip through the independent analog voltage pin into a high-voltage square wave with the corresponding duty cycle. Each update of the drive voltage is completed in microseconds, without the need for CAN or SPI bus scheduling; in addition, the control loops of the two types of actuators are equipped with optocoupler isolators at the physical level to ensure that the digital ground and analog ground are connected at a single point, avoiding high-frequency switching noise from being coupled to the low-speed control signal through the ground loop; based on this control method, the low refresh rate of the CAN bus (100Hz) does not require high-frequency refresh; The high frequency (Hz) makes the control calculation load of the electrostatic hydraulic conversion unit extremely light and the communication delay fixed and controllable, eliminating the risk of bus conflict and data packet loss. The onboard analog PID circuit can respond to the dynamic commands of the solid electro-actuated material in microseconds without bus arbitration, so as to give full play to its high frequency characteristics. At the same time, the main control chip only needs to output two analog voltage values ​​to simultaneously schedule two types of drive units, which greatly reduces the contention for on-chip peripherals and interrupt resources. This allows the entire robot control system to maintain deterministic real-time response capability even with increased complexity, and reserves ample software and hardware resources for future expansion of more drive units.

[0072] In another implementation, under the third structural type described above, at the control signal scheduling level, the drive signals of the two types of actuators can be unified into pulse width modulation (PWM) form. However, the carrier frequency and duty cycle adjustment strategies are set differently according to their respective physical characteristics. Specifically, the PWM carrier frequency of the solid electro-actuated material is set to above 10 kHz (far higher than its mechanical natural frequency). Utilizing its capacitive load characteristics, the effective average voltage applied to the thin film is equivalently changed by adjusting the duty cycle, thereby controlling its in-plane expansion strain. Meanwhile, the PWM carrier frequency of the electrostatic hydraulic conversion unit is set to 500 Hz~2 Hz. The high-frequency pulse sequence, at kHz (far higher than its liquid pressure transmission cutoff frequency but lower than the frequency band of solid-state units), utilizes the viscous damping of the insulating fluid and the mechanical inertia of the shell's elastic buckling as a natural low-pass filter to smoothly demodulate the duty cycle information contained in the high-frequency pulse sequence into a stable internal liquid pressure, which is then converted into the corresponding axial contraction displacement. Both types of PWM signals are generated by the advanced timer module of the main control chip and drive the corresponding high-voltage switching transistor arrays through independent GPIO pins and optocoupler isolation. Fully digital pulse width command issuance can be achieved without going through a CAN bus or analog PID circuit. Under this architecture, the main control chip no longer outputs analog voltage reference values, but directly updates the comparison registers (CCR values) of the two PWM channels. The duty cycle update of each channel can be synchronized with the robot's motion planning cycle (typically 1 kHz), and the drive instructions of the two types of actuators are output in complete parallel at the timer hardware level without occupying CPU interrupt resources.Under this control method, firstly, the electrostatic hydraulic conversion unit no longer relies on a high-precision digital-to-analog converter (DAC) to generate an analog reference voltage, completely eliminating the problems of temperature drift, zero drift, and noise coupling in the analog signal link. This allows the control accuracy of the contraction displacement to be entirely determined by the digital pulse width resolution (e.g., 16-bit PWM corresponding to 65536 levels of adjustment), significantly improving the repeatability and anti-interference capability of open-loop control. Secondly, the two types of actuators share the same high-voltage DC bus (e.g., uniformly boosted to 5 kV), distributing energy only through two independent PWM chopper switches. This simplifies the high-voltage power supply module from a "dual-channel isolated output" to a "single-channel centralized power supply + dual-channel time-division chopper" topology, significantly reducing the size, weight, and hardware cost of the power system, while improving the dynamic allocation flexibility of energy at the bus level. Furthermore, since the PWM carrier frequencies of the two types of actuators belong to different frequency bands (solid-state unit > 10 kHz, electrostatic hydraulic unit < 2 kHz), the control accuracy is significantly improved. The two do not produce frequency aliasing or beat frequency interference at the electrical level. Moreover, the electrostatic hydraulic unit can obtain smooth hydraulic output without the need for additional analog filters due to the mechanical low-pass filtering characteristics of the liquid itself, avoiding the high-frequency ripple excitation of undesirable parasitic oscillations in the shell structure. Finally, this full-pulse control scheme unifies the control interface of the high-speed dynamic unit and the low-speed heavy-load unit into a digital pulse width register, enabling the main control chip to schedule two types of actuators with different physical mechanisms with the same instruction format (period, duty cycle). This provides a standardized drive abstraction layer for the control algorithm of the bionic wrist, and also reserves sufficient digital control expansion space for future implementation of more complex stepping micro-motion or impact fast response by changing the pulse sequence timing (such as pulse count, burst pulse train and other advanced modulation modes).

[0073] In other embodiments, the flexible actuation unit 20 may also employ other non-electrically actuated actuation elements such as shape memory alloys or pneumatic artificial muscles, as long as they can generate the required contraction or tension force and transmit it to the joint through tendineae.

[0074] Those skilled in the art will understand that the aforementioned solid electro-actuated material and electro-hydraulic conversion unit are specific implementations of the electro-actuated functional component described in this application. As long as the electro-actuated functional component can generate anisotropic active deformation under electric field excitation and transmit the deformation to the joint through biomimetic tendons, it is acceptable.

[0075] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: by employing multiple bionic joints connected by bionic soft tissue and multiple independent drive units, a unity of multi-degree-of-freedom motion and inherent compliance is achieved, effectively solving the problems of limited range of motion, lack of compliance adaptation mechanism, and insufficient dynamic cushioning capacity of traditional rigid wrist mechanisms. It possesses multi-degree-of-freedom motion capability, inherent compliance, and wide-range motion capability, and can adapt to complex operating environments while providing effective cushioning. Through this bionic design, this application aims to break through the limitations of traditional rigid structures and achieve high degree of freedom, inherent compliance, and full-posture reachable wrist motion.

[0076] This embodiment of the electro-actuated flexible bionic wrist is constructed by connecting multiple independent bionic joints using bionic soft tissue. For example, the bionic soft tissue can be an elastic membrane or flexible fiber bundle, directly connecting the rigid portions of adjacent bionic joints. This connection method allows for relative movement between the bionic joints and provides a degree of passive compliance. As an optional implementation, the bionic soft tissue can consist of multiple independent elastic connectors distributed circumferentially around the bionic joints to simulate the restraining effect of ligaments.

[0077] In one embodiment, the biomimetic distal radius joint is specifically designed as an elliptical joint. This means that the contact surfaces of the two main moving parts of the joint are shaped into ellipses. For example, one part may have a convex elliptical surface, while the other part has a matching concave elliptical surface. This geometry allows the joint to rotate in two orthogonal directions, such as flexion and extension and partial yaw of the wrist, while limiting rotation along the long axis, thus providing a stable motion trajectory.

[0078] According to one embodiment of this application, the proximal bionic skeletal component 1 includes a bionic distal radius 11 and a bionic distal ulna 12, and the distal bionic skeletal component 2 includes at least one bionic carpal bone. The bionic distal radius 11 and the bionic distal ulna 12 are movably connected via a bionic distal radioulnar joint, and the bionic carpal bone is movably connected to the bionic distal radius 11, the bionic distal ulna 12, and the hand skeletal component, respectively. The use of at least one bionic carpal bone at the distal end, which is movably connected to the distal radius, the distal ulna, and the hand skeletal component, more closely resembles the anatomical morphology of a real wrist joint with "multiple bone blocks and multiple articular surfaces," thus facilitating the reproduction of multi-degree-of-freedom complex movements of the wrist joint.

[0079] In one embodiment, the proximal bionic skeletal component specifically includes a bionic distal radius and a bionic distal ulna, wherein the bionic distal radius is the distal portion of the bone near the thumb in the bionic forearm, and the bionic distal ulna is the distal portion of the bone near the little finger in the bionic forearm. The two respectively simulate the double-bone structure of the human forearm and together form the proximal support base of the bionic wrist joint; the distal bionic skeletal component includes at least one bionic carpal bone (such as including at least one of the bionic lunate, bionic scaphoid, and bionic triquetrum), which is movably connected to the bionic distal radius, the bionic distal ulna, and hand skeletal components (such as metacarpals). More specifically, the distal ends of the bionic radius and ulna are connected by a bionic distal radioulnar joint, which allows relative rotation between the two during the rotation of the bionic wrist joint, thereby enabling pronation and supination of the forearm. The movable connection between the bionic wrist bones and the distal ends of the bionic radius and ulna forms the radiocarpal joint, providing the flexion, extension, and radial / ulnar deviation degrees of freedom of the bionic wrist joint. The movable connection between the bionic wrist bones and the skeletal components of the hand enables the linkage between the bionic wrist bones and the skeletal components of the hand. Based on the aforementioned skeletal structure, a flexible actuation unit (e.g., made of dielectric elastomer material) undergoes active deformation under electric field excitation, and its output end pulls the bionic tendon cable fixedly connected to it. Under the constraint and guidance of the bionic tendon sheath and trochlear system (e.g., passing through the bionic trochlear structure or tendon sheath channel set on each bionic skeletal component), the bionic tendon cable slides along a predetermined path, preventing the bionic tendon cable from buckling like a bowstring or shifting laterally during bionic joint movement. The end of the bionic tendon cable is connected to the distal end of the bionic radius, the distal end of the bionic ulna, or the bionic carpal bone through bionic attachment points (e.g., anchoring structures or movable connection structures, the movable connection structures including but not limited to groove connections or sliding attachment points), transmitting the driving force to the corresponding bionic skeletal component. Under the tension of the bionic tendon cable, each bionic skeletal component rotates around the corresponding bionic joint axis, thereby driving the multi-degree-of-freedom wrist joint complex in single-degree-of-freedom or multi-degree-of-freedom compound movements in the flexion-extension, radial / ulnar deviation, and pronation / supination directions.Based on this skeletal structure, by setting the bionic distal radius and distal ulna as a double-bone structure connected by a bionic distal radioulnar joint, the bionic wrist can simulate the natural movement law of the bionic distal radius rotating around the bionic distal ulna in the human forearm during pronation / supination movements, solving the defect of traditional single-axis joints that cannot achieve axial rotation. In addition, by setting at least one bionic carpal bone as a transitional force transmission component between the bionic distal radius, distal ulna and hand skeletal components, the driving force from the forearm is smoothly transmitted to the hand skeletal components after mechanical redistribution through the bionic carpal bone, avoiding stress concentration caused by the driving force acting directly on the hand skeletal components, thus improving the load-bearing capacity and service life of the bionic wrist. Through the path constraint of the bionic tendon sheath and pulley system, it is ensured that the bionic tendon slides in close contact with the bionic bone surface during multi-degree-of-freedom compound movements, which not only improves the force transmission efficiency, but also avoids the interference of the bionic tendon with other structures, thus significantly improving the structural compactness and motion reliability of the entire bionic wrist.

[0080] For example, in the field of industrial bionic robots, this bionic wrist can serve as the end-effector of a robotic arm, working in conjunction with a bionic hand to achieve multi-angle posture adjustments during assembly, sorting, and handling operations. Specifically, in confined workstations, the end-effector tool or bionic hand can be adjusted to the target orientation using flexion / extension and radial / ulnar degrees of freedom, while pronation / supination degrees of freedom enable tool or material flipping operations, effectively reducing the frequency of robot body movement and large-amplitude arm swings, thus improving work efficiency and positioning accuracy. In humanoid robots designed for precision operations, this bionic wrist can be used for operations requiring high positional accuracy and force control, such as electronic component insertion and wire harness terminal docking. Its inherent flexible drive characteristics and impedance adjustment capabilities can adaptively adjust wrist stiffness according to different operational tasks: for example, providing higher stiffness to ensure positioning accuracy during precision insertion, and switching to a lower stiffness mode when contacting fragile workpieces. This design provides smooth force control interaction, avoiding workpiece damage and significantly improving operational safety. In service-oriented bionic robots, this bionic wrist can be integrated into domestic service or elderly / disabled assistance robot platforms to perform daily tasks involving multi-angle wrist adjustment, such as holding water cups, delivering tools, and opening and closing doors and windows. Its bionic skeletal structure and drive method make the robot's movements more natural and smooth when performing these operations, enhancing the friendliness of human-computer interaction and the smoothness of task execution. In the field of special bionic robots, this bionic wrist, with its compact structure, multi-degree-of-freedom motion capability, and flexible drive's impact / overload resistance characteristics, can perform delicate operations such as valve rotation, cable plugging and unplugging, and tool switching in confined, complex, and high-risk working environments. It also utilizes its joint self-sensing capability to achieve real-time perception of the contact force during operation, providing force feedback to remote operators and improving the safety and success rate of remote operation.

[0081] According to one embodiment of this application, the bionic distal radioulnar joint includes a bionic triangular fibrocartilage complex; the bionic triangular fibrocartilage complex is made of a flexible elastomer material, with its proximal end fixed to the distal end 12 of the bionic ulna and its distal end attached to the ulnar notch of the distal end 11 of the bionic radius; the bionic triangular fibrocartilage complex provides elastic restraint and axial cushioning during wrist rotation and lateral swing, and maintains the stability of the distal radioulnar joint. Using a bionic triangular fibrocartilage complex made of a flexible elastomer material allows the bionic wrist to provide a near-human-like nonlinear damping sensation during rotation, making the bionic wrist appear more natural during rotation and avoiding the abruptness of mechanical structures.

[0082] In one embodiment, the bionic distal radioulnar joint includes a bionic triangular fibrocartilage complex disposed between the distal end of the bionic ulna and the ulnar notch of the distal end of the bionic radius. Specifically, the distal end of the bionic ulna is the end of the bone near the little finger in the bionic forearm, and the distal end of the bionic radius is the end of the bone near the thumb in the bionic forearm. The two are arranged side by side and rotatably connected by the bionic distal radioulnar joint; the ulnar notch is a concave structure on the medial side of the distal end of the bionic radius (i.e., the side near the distal end of the bionic ulna) to accommodate and limit the distal portion of the bionic triangular fibrocartilage complex. The biomimetic triangular fibrocartilage composite is made of a flexible elastomer material (such as silicone rubber, polyurethane elastomer or thermoplastic elastomer). Its proximal end is fixedly connected to the area near the ulnar styloid process of the distal end of the biomimetic ulna, and its distal end is attached to the edge of the ulnar notch of the distal end of the biomimetic radius, thereby forming a flexible connection between the distal end of the biomimetic radius and the distal end of the biomimetic ulna. During operation, when the bionic wrist joint performs pronation or supination, the distal end of the bionic radius needs to rotate relative to the distal end of the bionic ulna. At this time, the bionic triangular fibrocartilage complex undergoes elastic deformation due to stretching or compression, providing guidance and limitation for the relative movement between the two bones and preventing the distal end of the bionic radius from deviating excessively from its movement trajectory during rotation. When the bionic wrist joint performs lateral swing (radial deviation / ulnar deviation) or flexion and extension movements, the external force is transmitted to the distal ends of the bionic radius and ulna through the bionic wrist bones. In this process, the bionic triangular fibrocartilage complex acts as an elastic buffer element, absorbing and dissipating part of the impact load, while limiting the excessive separation or displacement of the distal end of the bionic radius relative to the distal end of the bionic ulna. Based on the above structure, a biomimetic triangular fiber cartilage composite made of flexible elastomer material is used to establish a flexible elastic constraint between the distal ends of the biomimetic radius and ulna. This ensures the flexibility of axial rotation during simulated forearm rotation while preventing impact or dislocation of the two bone ends, significantly improving the stability and structural integrity of the biomimetic wrist joint. The elastic cushioning function provided by the biomimetic triangular fiber cartilage composite during lateral swing and flexion-extension movements effectively absorbs the impact load in the complex movements of the wrist joint and buffers the axial load, preventing excessive impact force from directly acting on the articular surface of the biomimetic distal radioulnar joint, thereby extending the service life of the biomimetic wrist joint. The elastic constraint of the biomimetic distal radioulnar joint by the biomimetic triangular fiber cartilage composite ensures that the distal ends of the biomimetic radius and ulna maintain the correct relative position during static load and dynamic movement of the wrist joint, maintaining the stability of the distal radioulnar joint and providing a stable support platform for subsequent precise movements of the biomimetic wrist bones and hand.

[0083] For example, when a robot needs to install circuit board components in a confined space, its end effector, the bionic wrist, needs to perform a combined motion of wrist flexion and radial deviation while suspended to tilt and insert the electronic components into designated holes. During this process, the distal radius and distal ulna of the bionic wrist generate significant axial torque and shear force due to the end-load and combined joint motion. If there is a lack of elastic constraint between them, it will cause unintended relative movement of the distal radioulnar joint, thus affecting the positioning accuracy of the end effector and even causing the force transmission direction of the bionic tendon drive system to deviate and the transmission efficiency to decrease. By incorporating a biomimetic triangular fibrocartilage complex, a flexible and elastic connection is established between the distal ends of the biomimetic radius and ulna. On the one hand, the elastic deformation generated under axial torsion can absorb some of the impact energy, and automatically restore the initial relative positions of the distal ends of the biomimetic radius and ulna after the torsion is released. This ensures that the distal radioulnar joint can be reset to the precise reference position after each movement, thereby guaranteeing the repeatability of the biomimetic hand in multi-degree-of-freedom compound motion and significantly improving the success rate of assembly operations. On the other hand, when the biomimetic wrist is accidentally subjected to an unexpected impact exceeding the rated load during operation (such as component jamming during assembly or collision between the hand and the fixture), the biomimetic triangular fibrocartilage complex can preferentially undergo large deformation to absorb the impact energy, effectively protecting the articular surfaces of the distal radioulnar joint and the biomimetic tendineae transmission system from overload damage. This reduces the failure rate and maintenance costs of the biomimetic wrist and significantly improves the reliability and environmental adaptability of the humanoid robot in continuous precision working environments.

[0084] According to one embodiment of this application, the bionic tendon cables of the pronation drive group and the supination drive group are arranged in a cross-spiral manner on the bionic forearm: wherein, the bionic tendon cables of the pronation drive group originate from the ulnar side of the bionic ulna distal end 12 and cross obliquely to the palmar side of the bionic radius distal end 11; the bionic tendon cables of the supination drive group originate from the palmar side of the bionic radius distal end 11 and cross obliquely to the dorsal side of the bionic ulna distal end 12; the bionic tendon sheath and trochlear system 6 includes cross-guided trochlears respectively provided on the radius and ulna to limit the radial displacement of the bionic tendon cables during rotation.

[0085] In one embodiment, the distal end of the bionic ulna is the bone end of the bionic forearm near the little finger, and the distal end of the bionic radius is the bone end of the bionic forearm near the thumb. The two are arranged side by side and are rotatably connected by the bionic distal radioulnar joint. The ulnar side refers to the side of the distal end of the bionic ulna facing the distal end of the bionic radius (i.e., the side closer to the little finger), the palmar side refers to the surface of the distal end of the bionic radius facing the palm (i.e., the flexor side), and the dorsal side refers to the surface of the distal end of the bionic ulna facing the back of the hand (i.e., the extensor side). During operation, the pronation-driven group of bionic tendons originates from the ulnar side of the distal end of the bionic ulna, crosses the interosseous region between the bionic radius and ulna in an oblique direction, and crosses to the palmar side of the distal end of the bionic radius; the supination-driven group of bionic tendons originates from the palmar side of the distal end of the bionic radius, crosses the interosseous region in the opposite direction in an oblique path, and crosses to the dorsal side of the distal end of the bionic ulna; the two tendons form a cross-spiral configuration in the interosseous region of the bionic forearm, and their directions of travel are opposite, forming a pair of mirror-symmetrical spiral driving paths. In the aforementioned path, each bionic tendon cable passes through a cross-guided trolley disposed on the bionic radius and bionic ulna. The cross-guided trolley is located on the surface of the bionic radius and bionic ulna and has a guide groove or guide ring structure. The bionic tendon cable passes through the guide groove or guide ring to define the lateral position of the tendon cable on the bone surface. Thus, when the bionic wrist joint performs pronation or supination movements, the bionic tendon cable is always constrained to slide on a predetermined oblique path and will not slip radially or dislodge due to relative rotation of the bones. Through the aforementioned cross-spiral arrangement, when the pronation drive group actively contracts (i.e., its flexible drive unit undergoes active deformation under electric field excitation, pulling the corresponding bionic tendineae), the bionic tendineae apply an oblique pulling force from the distal end of the bionic ulna to the distal end of the bionic radius. This pulling force generates a torque around the axis of the bionic forearm, driving the distal end of the bionic radius to rotate relative to the distal end of the bionic ulna, thus realizing the forearm pronation action. When the supination drive group actively contracts, the bionic tendineae apply an oblique pulling force in the opposite direction from the distal end of the bionic radius to the distal end of the bionic ulna, driving the distal end of the bionic radius to rotate in the opposite direction, thus realizing the forearm supination action. When the two drive groups work together (for example, maintaining a certain tension simultaneously during grasping), the opposing torques generated by the two groups are superimposed or canceled out, which can achieve precise control of the forearm pronation / supination angle and provide stiffness and damping against axial rotation when disturbed by external forces.In the above structure, by setting the pronation and supination drive groups of bionic tendons as mirror-symmetric paths of cross-spirals, the two groups of tendons form antagonistic oblique tension lines between the distal ends of the bionic radius and ulna. This achieves independent driving and precise control of the forearm's pronation and supination rotational movements, solving the technical problems of difficult axial rotational freedom drive force arrangement, small driving torque, and imprecise control in traditional bionic wrists. By setting cross-guided pulleys on the bionic radius and ulna respectively, the lateral position of the cross-spiral bionic tendons during movement is forcibly constrained, ensuring that the bionic tendons always follow the predetermined oblique path during the large-range rotational movements of the distal radioulnar joint. The sliding mechanism effectively prevents radial displacement, slippage, or interference with other structures caused by relative bone rotation of the chordae tendineae, ensuring the stability and transmission efficiency of the force transmission path. The cross-spiral arrangement allows the pronation and supination drive groups of bionic chordae tendineae to form spatially intersecting but non-interfering travel paths in the interosseous region, making full use of the narrow internal space of the bionic forearm. It achieves the parallel arrangement of two sets of independently driven chordae tendineae within a limited space, improving the structural compactness and integration of the bionic wrist. Through the coordinated control of the two antagonistic drive groups in the pronation / supination direction, the bionic wrist joint can generate controllable rotational stiffness when bearing axial loads, providing stable posture support for the subsequent precise operation of the bionic hand.

[0086] For example, when a robot needs to screw in a cable connector plug in a space-constrained environment such as a cabinet back panel, its end effector bionic wrist needs to maintain the gripping posture of the bionic hand while performing a forearm supination movement of approximately 90° to align the cable plug with the socket and rotate it to lock it in place. In traditional bionic wrists, the pronation / supination driving force is usually achieved by a single drive group located on the back of the forearm through linear traction. In this method, the lever arm length changes significantly with the joint angle during the driving process, resulting in a non-linear decrease in rotational torque output. Furthermore, the single drive group cannot provide reverse damping during the forearm supination movement. When there is axial resistance caused by misalignment between the cable plug and the socket, the bionic wrist is prone to unexpected rebound or jitter in the pronation direction, causing the plug to fail to lock in place accurately. In this invention, when the robot control center issues a supination command to the bionic wrist, the flexible drive unit of the supination drive group actively contracts under electric field excitation, pulling its bionic tendineae along a cross-spiral path from the palmar side of the distal end of the bionic radius to the dorsal side of the distal end of the bionic ulna. The resulting oblique pulling force forms a rotational torque around the axis of the bionic forearm, driving the distal end of the bionic radius to rotate relative to the distal end of the bionic ulna, thus achieving a smooth supination movement of the forearm. At the same time, the control center monitors the tension of the bionic tendineae of the pronation drive group in real time through a tension sensor, and maintains the drive group to output a counter-torque (i.e., coordinated contraction) that is opposite to the direction of supination but smaller in value. This counter-torque provides controllable rotational damping for the bionic wrist joint during the forearm supination movement, resisting the unexpected axial force impact caused by misalignment of the connector plug and socket, and preventing unexpected rebound and jitter. Throughout the entire supination process, the cross-guided pulleys set on the bionic radius and bionic ulna always constrain the two sets of bionic tendineae on their respective predetermined oblique paths. Even when the bionic distal radioulnar joint undergoes a wide range of rotational movements, the bionic tendineae will not experience radial slippage or dislodgement due to the relative rotation of the bones, ensuring the stability of the force transmission path. This allows the driving force of the supination drive group to be transmitted accurately and efficiently to the distal end of the bionic radius. Even if the cable plug generates additional pronation resistance due to manufacturing tolerances or installation angle deviations, this resistance is transmitted to the two sets of cross-spiral bionic tendineae via the bionic distal radius and ulna. This resistance is balanced by the controllable reverse torque provided by the synergistically contracting pronation drive group and the stable tension generated by the bionic tendineae under the constraint of the cross-guided trolley. This prevents the plug locking angle from shifting or the connection from being incomplete, thus effectively reducing the risk of poor signal contact due to an improperly locked plug while ensuring operational success. Furthermore, after the plug is screwed in, both drive groups can simultaneously increase their output to significantly improve rotational stiffness, effectively resisting the loosening torque caused by cable elasticity or vibration, ensuring the connector remains locked throughout subsequent operations. The above process fully demonstrates the core technological advantages of the cross-spiral bionic tendineae arrangement in achieving precise pronation / supination drive and stiffness self-adjustment through antagonistic synergistic control.

[0087] In some of the solutions described above in this application, a pronation drive group and a supination drive group are proposed to provide pronation and supination power for the bionic distal radius joint. However, in the actual bionic tendine cord arrangement process, if the tendine cord path of the drive group is not properly designed, it is easy to cause tendine cord interference, path redundancy or torque output imbalance when performing rotational movements, which in turn affects the smoothness of the wrist mechanism's rotational movement and space utilization.

[0088] In this regard, this application further proposes that the bionic tendons of the pronation-driven group and the supination-driven group are arranged in a mutually crossing manner. This arrangement means that the movement paths or lines of action of the bionic tendons of the pronation-driven group and the supination-driven group intersect or cross within the electrically actuated flexible bionic wrist, especially near the bionic distal radius joint. Specifically, this can be achieved by physically overlapping or interlacing the two groups of tendons in space; for example, one group of tendons passes above or below the other. Another implementation method is that the attachment points and guiding paths of the tendons are designed so that during pronation or supination movements of the bionic distal radius joint, the tendons can spiral or wrap around the joint axis, thus naturally forming intersecting mechanical action paths.

[0089] In one embodiment, the distal end of the bionic ulna is the bone end of the bionic forearm near the little finger, and the distal end of the bionic radius is the bone end of the bionic forearm near the thumb. The two are arranged side by side and are rotatably connected by the bionic distal radioulnar joint. The ulnar side refers to the side surface of the distal end of the bionic ulna facing the little finger (i.e., the outer surface away from the distal end of the bionic radius), the palmar side refers to the surface of the distal ends of the bionic radius and ulna facing the palm (i.e., the flexor side), and the dorsal side refers to the surface of the distal ends of the bionic radius and ulna facing the back of the hand (i.e., the extensor side). Under the above orientation definition, the pronation-driven group of bionic tendons originates from the ulnar side (i.e., the little finger side surface) of the distal end of the bionic ulna, crosses the interosseous region between the bionic radius and the bionic ulna in an oblique direction, and crosses to the palmar side (i.e., the palmar side surface) of the distal end of the bionic radius; the supination-driven group of bionic tendons originates from the palmar side of the distal end of the bionic radius, crosses the interosseous region in an oblique path in the opposite direction, and crosses to the dorsal side (i.e., the dorsal side surface) of the distal end of the bionic ulna; the two bundles of bionic tendons form a cross-spiral configuration in the interosseous region of the bionic forearm, and their directions of travel are opposite, forming a pair of mirror-symmetrical spiral driving paths. In the aforementioned path, each bionic tendon cable passes through a cross guide trolley disposed on the bionic radius and bionic ulna. The cross guide trolley is fixedly disposed on the surface of the bionic radius and bionic ulna, and each cross guide trolley has a guide groove or guide ring structure. The bionic tendon cable passes through the guide groove or guide ring and slides along it, so that when the bionic wrist joint performs pronation or supination movements, the bionic tendon cable is always constrained to slide on a predetermined oblique path and will not cause radial slippage or dislodgement due to the relative rotation between the bionic radius and bionic ulna. Through the aforementioned cross-spiral arrangement, when the pronation drive group actively contracts (i.e., its flexible drive unit undergoes active deformation under electric field excitation, pulling the corresponding bionic tendineae), the bionic tendineae apply an oblique pulling force from the ulnar side of the distal bionic ulna to the palmar side of the distal bionic radius. Since the line of action of this pulling force does not pass through the rotation axis of the bionic forearm, a torque is generated around this axis, driving the distal bionic radius to rotate relative to the distal bionic ulna, thus achieving forearm pronation. When the supination drive group actively contracts, the bionic tendineae apply a reverse oblique pulling force from the palmar side of the distal bionic radius to the dorsal side of the distal bionic ulna, similarly generating a reverse torque around the rotation axis, driving the distal bionic radius to rotate in the opposite direction, thus achieving forearm supination. When the two drive groups work together, the opposite torques generated by them are superimposed or canceled out, enabling precise control of the forearm pronation / supination angle and providing stiffness and damping against axial rotation when subjected to external force disturbances.In the above structure, by setting the pronation and supination drive groups of bionic tendons as mirror-symmetric paths of cross-spirals, the two sets of bionic tendons form mutually antagonistic oblique tension lines between the distal ends of the bionic radius and ulna. This achieves independent driving and precise control of the forearm's pronation and supination rotational movements, solving the technical problems of difficult axial rotational freedom drive force arrangement, small driving torque, and imprecise control in traditional bionic wrists. By setting cross-guide pulleys on the bionic radius and ulna respectively, the lateral position of the cross-spiral bionic tendons is forcibly constrained during movement, ensuring that the bionic tendons always slide along the predetermined oblique path during the large-range rotational movements of the distal radioulnar joint, effectively preventing the bionic tendons from sliding. The radial offset, slippage, or interference with other structures caused by the relative rotation between the bionic radius and bionic ulna ensures the stability and transmission efficiency of the force transmission path. The cross-spiral arrangement allows the bionic tendons of the pronation and supination drive groups to form spatially intersecting but non-interfering travel paths in the interosseous region, making full use of the narrow internal space of the bionic forearm. It achieves the parallel arrangement of two sets of independent drive tendons within a limited space, improving the structural compactness and integration of the bionic wrist. Through the coordinated control and simultaneous contraction of the two antagonistic drive groups in the pronation / supination direction, the bionic wrist joint can generate controllable rotational stiffness and damping when bearing axial loads, providing stable posture support and anti-disturbance capability for the subsequent precise operation of the bionic hand.

[0090] For example, when a robot needs to perform the screw-in installation of an RF coaxial connector in a space-constrained environment such as a cabinet back panel, its end-effector wrist needs to perform a forearm supination motion of about 90° while maintaining the posture of the bionic hand holding the connector plug to align the plug with the socket and rotate to lock it. During this operation, when the robot control center issues a supination command to the bionic wrist, the flexible drive unit of the supination drive group actively contracts under electric field excitation, pulling its bionic tendineae along a cross-spiral path from the palmar side of the distal end of the bionic radius to the dorsal side of the distal end of the bionic ulna. The resulting oblique pulling force forms a rotational torque around the axis of the bionic forearm, driving the distal end of the bionic radius to rotate relative to the distal end of the bionic ulna, achieving a smooth supination of the forearm and gradually screwing the connector plug into the socket thread. At the same time, the control center monitors the tension of the pronation drive group's bionic tendineae in real time through a tension sensor and maintains the drive group to output a moderate counter-torque opposite to the supination direction. This counter-torque provides controllable rotational damping for the bionic wrist joint during the forearm supination movement to resist unexpected axial resistance impacts caused by misalignment of the plug and socket threads or differences in the lead of the thread start section, preventing the bionic wrist from experiencing unexpected pronation rebound or jitter, and ensuring that the plug can be screwed into the threaded hole at a stable angular velocity. Throughout the entire supination process, the cross-guided pulleys set on the bionic radius and bionic ulna always constrain the two sets of bionic tendineae on their respective predetermined oblique paths. Even when the bionic distal radioulnar joint undergoes a large range of rotational movements (for example, in the middle stage of the supination process, when the bionic distal radius and bionic distal ulna have undergone a relative rotation of about 45°, at which point the geometry of the interosseous region changes significantly), the bionic tendineae can still maintain a stable lateral position under the constraint of the guide grooves of the cross-guided pulleys. They will not experience radial slippage, dislodgement, or jamming due to relative bone rotation, thus ensuring the stability of the force transmission path. This allows the driving force of the supination drive group to be transmitted accurately and efficiently to the bionic distal radius. After the connector plug is fully screwed into the bottom of the socket thread, the control center instructs the pronation drive group and the supination drive group to simultaneously increase the output tension. Under the constraint of the cross-guided trolley, the two sets of cross-helical bionic tendons apply opposite oblique pulling forces to the distal ends of the bionic radius and ulna along their respective predetermined paths. These forces form a pair of balanced torques on the bionic wrist joint, switching the forearm rotational stiffness from a compliant mode in motion to a high-stiffness holding mode in the locked state. This effectively resists the loosening torque caused by cable elasticity, equipment vibration, or external force contact, ensuring that the connector maintains a reliable locked state throughout subsequent operations. During the above operation, the cross-helical arrangement provides sufficient rotational drive torque and a smooth torque output curve, effectively avoiding the torque attenuation problem caused by the shortening of the lever arm when the rotation angle increases, as seen in traditional straight-pull tendon arrangements. This significantly improves the assembly success rate and extends the service life of the bionic wrist.

[0091] Through the above technical solution, this application effectively solves the problem that improper design of the tendon cable path in the drive group during the arrangement of bionic tendon cables can easily lead to tendon cable interference, path redundancy, or torque output imbalance during rotational movements. Specifically, the bionic tendon cables of the pronation drive group and the supination drive group are arranged in a cross-shaped manner, optimizing the rotational power transmission path of the electro-actuated flexible drive bionic wrist. This cross-layout can make full use of the limited internal space of the wrist, allowing the tendon cables to maintain a more reasonable tension distribution during movement, thereby effectively avoiding unexpected mutual compression or entanglement of the tendon cables when performing pronation or supination tasks, and improving the reliability of the mechanism. In addition, by changing the force vector direction of the tendon cables, the driving force can act more directly and smoothly on the bionic distal radius joint, thereby significantly improving the control accuracy and response stability of rotational movements. Overall, this solution enhances the structural compactness of the drive mechanism and ensures that the bionic wrist has better kinematic characteristics and higher space utilization when performing complex rotational tasks.

[0092] According to one embodiment of this application, the electro-actuated flexible actuation bionic wrist further includes a bionic carpal tube structure 7, which is used to accommodate and guide bionic tendineae and neurovascular simulated bundles passing through the wrist joint. During large-scale flexion, extension, and rotation of the wrist joint, the bionic tendineae passing through the joint will generate complex spatial displacements; therefore, the bionic curved tube can provide a closed channel, isolating the tendineae from the edges of other structures, significantly reducing wear rate and extending the service life of the actuation system; for bionic wrists with integrated sensors, the bionic carpal tube structure 7 can also accommodate signal lines, power lines, or even hydraulic / pneumatic hoses.

[0093] In one embodiment, the bionic carpal tunnel structure is formed by the palmar surface of bionic carpal bones (including bionic lunate, bionic scaphoid, and bionic triquetrum, etc.) and the bionic transverse carpal ligament. The bionic transverse carpal ligament is a band-like structure that crosses the palmar surface of the bionic carpal bones, with its two ends fixed to the radial and ulnar edges of the bionic carpal bones, respectively, thereby forming a closed or semi-closed tubular channel between the palmar surface of the bionic carpal bones and the bionic transverse carpal ligament. Inside this tubular channel, multiple bionic tendineae (including wrist flexion drive groups, wrist extension drive groups, and flexor tendineae extending to the hand, etc.) and neurovascular simulated bundles (e.g., flexible cable bundles used to transmit sensory or control signals) run in parallel. The bionic carpal tunnel structure spatially gathers and constrains these bionic tendineae and neurovascular simulated bundles to prevent them from being scattered, entangled, or interfering with other skeletal structures during bionic wrist joint movement. Furthermore, the bionic transverse wrist ligament is made of pre-stretched elastic fiber composite material (such as pre-stretched silicone rubber-based fiber-reinforced composite material or polyurethane elastomer composite film), which bears a certain pre-stretching stress in the initial installation state, thereby applying a slight radial compressive force to the bionic tendineae and neurovascular simulated bundles in the bionic carpal tunnel, so that they have a definite arrangement position and appropriate sliding damping when the bionic wrist joint is in a neutral position. During operation, when the bionic wrist joint performs palmar flexion, the angle between the bionic wrist bones and the hand skeletal components decreases, compressing the space on the palmar side of the bionic carpal tunnel. The bionic transverse carpal ligament, due to the compression from the palmar side of the bionic wrist bones, adaptively protrudes outward along the palmar direction (i.e., undergoes flexion deformation), resulting in a corresponding increase in the internal volume of the bionic carpal tunnel. This prevents the bionic tendineae and neurovascular simulated bundles inside the tunnel from being excessively compressed due to space compression. When the bionic wrist joint performs dorsiflexion, the angle between the bionic wrist bones and the hand skeletal components increases, stretching the space on the palmar side of the bionic carpal tunnel. The bionic transverse carpal ligament automatically retracts and resets due to the pre-tension stress, resulting in a corresponding decrease in the internal volume of the bionic carpal tunnel while still maintaining sufficient sliding clearance. This maintains appropriate constraint on the bionic tendineae and neurovascular simulated bundles, preventing them from loosening or swinging due to excessive space inside the bionic carpal tunnel. Through the adaptive deformation of the aforementioned bionic transverse carpal ligament, the pressure within the bionic carpal tunnel can be dynamically adjusted within the full range of motion of the bionic wrist joint, ensuring that it remains within the optimal working range that effectively constrains and guides the bionic tendineae and neurovascular simulated bundles without causing them to be excessively compressed.The aforementioned structure, through the establishment of a bionic carpal tunnel formed by the bionic carpal bones and the bionic transverse carpal ligament, centralizes and orderly guides multiple bionic tendineae and neurovascular bundles within the wrist joint region. This effectively avoids the loose distribution, entanglement, or interference with the skeletal structure among the bionic tendineae and between the bionic tendineae and the neurovascular bundles within the confined space of the bionic wrist joint, significantly improving the orderliness and compactness of the internal structure of the bionic wrist. By using pre-stretched elastic fiber composite material to fabricate the bionic transverse carpal ligament, the ligament can undergo reversible adaptive deformation in response to the flexion and extension movements of the bionic wrist joint, thereby dynamically adjusting the bionic carpal tunnel within the full range of motion of the bionic wrist joint. The pressure on the wrist joint allows the bionic tendon cable to slide smoothly at different wrist joint angles without excessive friction or jamming. This effectively prevents problems such as decreased transmission efficiency, reduced control precision, or premature wear of the bionic tendon cable caused by compression, significantly improving the transmission reliability and service life of the bionic wrist during long-term reciprocating motion. The bionic wrist tube structure also provides an independent space and sliding guide for the neurovascular simulation bundle, allowing the sensor signal cable or control cable to bend and stretch smoothly during wrist joint movement. This avoids the risk of breakage or poor contact caused by repeated bending or pulling of the signal cable, ensuring the signal transmission stability of the sensing system and the electrical reliability of the entire device.

[0094] For example, when a robot needs to continuously perform the operation of grasping small electronic components from a conveyor belt and placing them into a designated tray while operating at high speed, its end effector bionic wrist needs to rapidly perform palmar flexion-dorsiflexion reciprocating motions in each grasping cycle (e.g., palmar flexion during grasping to bring the bionic hand close to the conveyor belt surface, and dorsiflexion during placement to adjust the posture of the bionic hand). During this process, multiple flexor and extensor tendons running through the bionic carpal tunnel frequently slide with the rapid reciprocating motion of the bionic wrist joint, and there is a risk of friction and interference between the bionic tendons and between the bionic tendons and the surrounding skeletal structures due to relative motion. By employing the bionic carpal tunnel structure of this invention, multiple flexor and extensor tendons are centrally collected and arranged in an orderly manner within the bionic carpal tunnel. The tendons maintain a defined relative position through the internal separation and guidance of the bionic carpal tunnel, preventing entanglement or knotting during rapid reciprocating palmar flexion and dorsiflexion of the bionic wrist joint. This ensures the independent sliding freedom of each tendon, enabling the bionic hand to respond quickly and accurately to control commands during grasping and releasing actions. Simultaneously, when the bionic wrist joint rapidly switches from its palmar flexion limit to its dorsiflexion limit, the bionic transverse carpal ligament automatically retracts and resets under the stretching effect of the palmar side of the bionic carpal bone. The internal pressure of the bionic carpal tunnel is dynamically adjusted to a suitable level, effectively preventing the tendons from becoming stuck due to excessive pressure or loosening and wobbling due to insufficient pressure during high-speed sliding. This ensures smooth force transmission and rapid response of the bionic tendons. Furthermore, during the high-speed cycle of sorting operations, the parallel neurovascular simulation bundles (such as signal cables connecting the tactile sensors of the bionic hand) within the bionic carpal tube are always constrained in a predetermined position by the bionic carpal tube structure. Even under the high-frequency reciprocating flexion and extension movements of the bionic wrist joint, the signal cables smoothly bend and return to their original positions. The cables will not suffer fatigue fractures or poor contact due to repeated bending, pulling, or friction with the bionic tendineae, thus ensuring the stable transmission of tactile sensing signals. This allows the bionic hand to accurately sense contact force and slippage state when grasping small electronic components, and then adjust the grasping force in real time to prevent components from slipping or being damaged, significantly improving the success rate of sorting operations and the reliability of the robot's long-term operation.

[0095] According to one embodiment of this application, the bionic carpal tube 7 is internally divided into multiple independent tendon channels, including flexor tendon channels and neurovascular simulated bundle channels; the flexor tendon channels are lined with a low-friction coating; the neurovascular simulated bundle channels are used to arrange bionic nerves or bionic blood vessels.

[0096] In one embodiment, the flexor tendon channel is a sub-channel within the bionic carpal tunnel for the passage of flexor tendon chordaes (i.e., bionic tendon chordaes corresponding to the wrist flexion drive group and the finger flexion drive group). It extends from the proximal end to the distal end along the length direction of the bionic carpal tunnel, and its inner wall surface is coated or composited with a low-friction coating (e.g., polytetrafluoroethylene (PTFE) coating, diamond-like carbon (DLC) coating, or ultra-high molecular weight polyethylene lining). The low-friction coating provides a smooth sliding contact interface during the passage of the bionic tendon chordae, enabling the bionic tendon chordae to slide back and forth along the channel with extremely low frictional resistance during the flexion and extension movements of the bionic wrist joint. At the same time, the low-friction coating also has a certain degree of wear resistance, which can resist the wear of the bionic tendon chordae during long-term reciprocating sliding and maintain the surface smoothness of the inner wall of the channel. The neurovascular simulated bundle channel is a sub-channel within the bionic wrist tube for arranging bionic nerves or bionic blood vessels. The bionic nerves are, for example, flexible signal cables or fiber optic bundles for transmitting sensor or control signals, and the bionic blood vessels are, for example, flexible conduits for delivering hydraulic media or cooling fluid. This channel is physically isolated from the flexor tendon channel by a separating structure, allowing the bionic nerves and blood vessels to be arranged independently of the flexor tendons, without contact or interference. During operation, when the bionic wrist joint performs flexion, extension, or lateral swing movements, the flexor tendons slide along the low-friction coating surface within the flexor tendon channel. Due to the presence of the low-friction coating, the sliding friction between the flexor tendons and the channel wall is significantly reduced, allowing the output force of the flexible drive unit to be transmitted to the target skeletal component with higher efficiency. Simultaneously, the neurovascular simulated bundle bends or stretches within the independent neurovascular simulated bundle channel with the movement of the bionic wrist joint. However, because it is physically isolated from the flexor tendons, friction, entanglement, or compression with the sliding flexor tendons are avoided, thus maintaining its structural integrity and the continuity of signal / medium transmission. In addition, the setting of multiple independent channels allows the bionic tendineae or neurovascular simulated bundles in each channel to have a definite arrangement position and movement trajectory inside the bionic carpal tube. Even when the bionic wrist joint performs multi-degree-of-freedom compound movements (such as performing palmar flexion and radial deviation at the same time), the flexible strip elements in each channel can still slide or bend independently in their respective channel space, and will not be misaligned, crossed or stuck due to deformation of the internal space of the bionic carpal tube.The aforementioned structure, by dividing the interior of the bionic carpal tunnel into multiple independent tendon chordae channels, spatially classifies and physically isolates bionic tendon chordae and neurovascular simulated bundles with different functions. This fundamentally avoids the entanglement, friction, or interference of various flexible long strip components within the bionic carpal tunnel, significantly improving the orderliness and motion reliability of the internal structure of the bionic wrist joint region. By setting a low-friction coating on the inner wall of the flexor tendon channel, the frictional resistance of the flexor tendon chordae during sliding is greatly reduced. This reduces the additional driving force required by the flexible drive unit to overcome frictional losses, and also reduces heat accumulation and wear debris generation caused by friction, thereby improving energy utilization efficiency and extending the service life of the bionic tendon chordae and bionic carpal tunnel. Furthermore, by setting independent... The neurovascular simulation bundle channel ensures that the bionic nerves or blood vessels are not mechanically interfered with by the sliding of flexor tendons during the reciprocating motion of the bionic wrist joint. This avoids the risk of insulation damage, signal crosstalk, or breakage of signal cables due to repeated friction, and also avoids the risk of unstable flow or leakage of fluid conduits due to external pressure. This ensures the long-term stable operation of the bionic wrist sensing system and energy / medium transmission system. The separation structure of multiple independent channels makes maintenance and replacement inside the bionic wrist tube more convenient. For example, when a flexor tendon needs to be replaced due to wear, the old tendon can be pulled out from the corresponding flexor tendon channel and a new tendon can be inserted without disassembling or disturbing the neurovascular simulation bundle in other channels, which significantly reduces the difficulty and cost of maintenance.

[0097] For example, the bionic hand has multiple built-in tactile and force sensors. The sensor signals need to be transmitted back to the robot's control center via bionic nerves (i.e., flexible signal cables) within the bionic carpal tunnel. Simultaneously, the bionic tendons of the wrist flexion and finger flexion actuators of the bionic wrist need to slide frequently within the bionic carpal tunnel to perform grip force application and release actions. In this application scenario, if the bionic tendons and signal cables are not physically isolated within the bionic carpal tunnel, during grip force testing cycles (e.g., the bionic hand repeatedly performs grip-relaxation actions, while the bionic wrist joint simultaneously performs small-amplitude palmar flexion-dorsiflexion adjustments), the flexor tendons slide at high frequency with the drive commands, easily causing friction with the parallel signal cables. This leads to gradual wear of the signal cable sheath, introducing sensor signal noise or causing intermittent signal interruptions. Consequently, the control center cannot accurately obtain the subject's grip force feedback value, severely affecting the reliability of the evaluation results. By employing the bionic carpal tunnel internal partition structure of this invention, the flexor tendons are constrained within the flexor tendon channel lined with a low-friction coating. During the repetitive flexion and extension of the bionic wrist joint and the grip-relaxation cycle of the bionic hand, they consistently slide smoothly along the low-friction coating surface with low frictional resistance. Simultaneously, the flexible signal cable (i.e., the bionic nerve) connecting the bionic hand's tactile and force sensors is independently arranged within the neurovascular simulation bundle channel, physically isolated from the flexor tendon channel. Even when the bionic wrist performs complex movements common in grip strength testing (e.g., applying grip force simultaneously in a 10° palmar flexion position), the sliding of the flexor tendons and the bending of the signal cables occur within independent channel spaces, without contacting each other. The signal cables are not subjected to frictional wear or positional disturbance due to the reciprocating sliding of the flexor tendons, thus ensuring real-time and stable transmission of tactile and force signals. This allows the control center to obtain high signal-to-noise ratio grip force curves and contact force distribution data, providing accurate and reliable quantitative evidence for rehabilitation assessment. After the test, if a flexor tendon chord is found to be worn due to long-term testing, maintenance personnel can directly pull out the old tendon chord from the corresponding flexor tendon channel and insert a new tendon chord without touching the signal cable channel. The replacement process is simple and quick, without the need for rewiring or recalibrating the sensor, which significantly reduces the maintenance time and operating costs of the equipment, enabling the bionic robot platform to serve clinical rehabilitation assessment work stably for a long time.

[0098] According to one embodiment of this application, the electrically actuated flexible drive bionic wrist further includes a multimodal wrist sensing system. The multimodal wrist sensing system includes: a capacitive or resistive pressure sensor disposed between the distal radius 11 and the bionic lunate, for detecting axial loads on the wrist joint; angle sensors disposed at the distal radioulnar joint and the radiocarpal joint, respectively, for detecting wrist flexion / extension angles, radial / ulnar deviation angles, and forearm pronation / supination angles; and a chordae tendineae tension sensor disposed within the bionic carpal tunnel 7, for real-time monitoring of the chordae tendineae tension of each drive unit. The angle sensors and tension sensors, together with the flexible drive unit 4, form a closed-loop control circuit to achieve coordinated control and impedance modulation of antagonistic muscle groups during compound movements. The pressure sensor disposed between the distal radius and the lunate can directly sense vertical pressure (such as grip strength and support reaction force) on the hand. This allows the bionic wrist to not only "move to a certain position" but also "sense how much force was used," which is the foundation for achieving compliant control. The angle sensor does not only measure the "end position" but is directly installed on the anatomical joint surface to measure the relative rotation angle of the joint itself, which is more reflective of the real joint movement state than the solution that relies solely on the motor encoder.

[0099] In one embodiment, the pressure sensor is a capacitive or resistive pressure sensor, which is disposed at the articular surface between the distal end of the bionic radius and the bionic lunate. Specifically, the pressure sensor is embedded in the wrist joint surface of the distal end of the bionic radius (i.e., the load-bearing surface in contact with the bionic lunate) or in the proximal articular surface of the bionic lunate. When the bionic wrist joint is subjected to axial load (e.g., the vertical pressure transmitted from the bionic hand to the bionic wrist joint when grasping a heavy object), the pressure sensor detects the contact pressure between the distal end of the bionic radius and the bionic lunate in real time. The magnitude of the contact pressure directly reflects the axial load currently borne by the bionic wrist joint. Angle sensors are respectively set at the bionic distal radioulnar joint and the radiocarpal joint. Specifically, the first angle sensor (e.g., a magnetic rotary encoder or a capacitive angle sensor) set at the bionic distal radioulnar joint is used to detect the rotation angle of the distal radius relative to the distal ulna around the forearm axis, i.e., the forearm pronation / supination angle; the second angle sensor set at the radiocarpal joint (i.e., between the distal radius and the bionic carpal bones, and between the distal ulna and the bionic carpal bones) is used to detect the flexion-extension angle and radial / ulnar deviation angle of the bionic carpal bones relative to the distal radius and distal ulna, thereby obtaining the real-time pose information of the bionic wrist joint in the flexion-extension and lateral swing directions. The tension sensor is located inside the bionic wrist tube. Specifically, the tension sensor is a strain gauge tension sensor or a fiber Bragg grating tension sensor, which is connected in series on the path of each bionic tendon (for example, an annular strain sensing element fitted on the surface of the tendon when the bionic tendon passes through the bionic wrist tube) or fixed on the tendon guide structure on the inner wall of the bionic wrist tube, for real-time monitoring of the tension value of the bionic tendon corresponding to each flexible drive unit.Based on the aforementioned multimodal sensing system, the angle sensor and tension sensor, together with the flexible actuation unit, form a closed-loop control circuit. The workflow is as follows: The angle sensor detects the actual pose of the bionic wrist joint in real time (including flexion / extension angles, radial / ulnar deviation angles, and pronation / supination angles); the tension sensor detects the actual tension values ​​of each bionic tendinus in real time; the control unit compares the actual pose fed back by the angle sensor with the desired pose and calculates the pose deviation; simultaneously, based on the actual tension values ​​fed back by the tension sensor, it determines whether the current tension distribution of each actuation group meets the desired antagonistic balance; based on the pose deviation and tension deviation, the control unit uses a preset control algorithm (e.g., a force / position hybrid control algorithm or an impedance control algorithm). The required drive signal adjustment amount for each flexible drive unit is calculated and output to the corresponding flexible drive unit to adjust its output force. During compound movements, such as when performing a compound movement of palmar flexion and radial deviation of the wrist joint simultaneously, the wrist flexion drive group and the radial deviation drive group need to contract in coordination to achieve the target posture. At the same time, the wrist extension drive group and the ulnar deviation drive group, as antagonists, need to adjust their outputs accordingly to provide appropriate damping and stiffness. During this process, the angle sensor and tension sensor continuously provide real-time feedback information, and the control unit continuously adjusts the output of each drive group accordingly, so that the wrist joint always maintains the desired motion trajectory and appropriate impedance characteristics during compound movements, thereby achieving coordinated control and impedance regulation of antagonistic muscle groups. The aforementioned structure, through a pressure sensor positioned between the distal radius and the lunate bone, enables real-time direct measurement of the axial load of the bionic wrist joint. This allows the control system to sense the load status of the wrist joint and take timely protective measures (such as reducing drive output or triggering an overload alarm) when the load exceeds a safe threshold, effectively preventing mechanical damage to the bionic wrist due to overload. Angle sensors positioned at the distal radioulnar joint and radiocarpal joint, respectively, enable independent real-time detection of the three degrees of freedom (flexion / extension, radial / ulnar deviation, pronation / supination) of the bionic wrist joint, providing precise motion feedback information to the control system. This allows the bionic wrist to achieve precise position control and trajectory tracking. By using chordae tendineae tension sensors installed within the bionic carpal tunnel, direct monitoring of the output force of each flexible actuation unit is achieved. This enables the control system to accurately perceive the actual tension state of each bionic chordae tendineae, providing reliable feedback for the coordinated control and force distribution of the antagonistic actuation groups. By forming a closed-loop control circuit with the angle and tension sensors and the flexible actuation units, the bionic wrist can achieve dual closed-loop control of posture and force in compound movements. This involves position correction based on posture deviation and force distribution optimization based on tension deviation, thereby achieving precise coordinated control of antagonistic muscle groups and adaptive adjustment of impedance characteristics. This significantly improves the motion accuracy, anti-disturbance capability, and compliance of the bionic wrist in multi-degree-of-freedom compound movements.

[0100] For example, when a robot needs to perform dust-free clamping and installation of micro-optical lenses under a microscope, its end effector, the bionic wrist, needs to simultaneously perform a compound movement of approximately 15° of wrist dorsiflexion and approximately 8° of radial deviation in a space-constrained assembly station to align the micro-lens held by the bionic hand with the lens mount mounting hole at a specific angle. During this operation, after the robot control center issues a compound movement command to the bionic wrist, the angle sensor located at the radiocarpal joint detects in real time the actual flexion-extension angle and radial deviation angle of the bionic wrist bone relative to the distal end of the bionic radius, and feeds back the actual angle value to the control unit. The control unit compares the actual angle with the desired angle. If it finds that the actual dorsiflexion angle is 14.5° (deviation of approximately 0.5°) and the actual radial deviation angle is 8.2° (deviation of approximately 0.2°), it calculates that the wrist extension drive group needs to increase its output force to compensate for the 0.5° insufficient dorsiflexion, and at the same time calculates that the ulnar deviation drive group needs to slightly increase its output to offset the 0.2° excessive radial deviation. Meanwhile, tension sensors installed within the bionic carpal tunnel monitor the actual tension values ​​of each bionic tendon in real time. If the current tension of the bionic tendon in the wrist extension drive group is 2.8N while the desired tension is 3.2N (a 0.4N tension deficiency), and the tension in the wrist flexion drive group (as the antagonist) is 1.2N, the control unit instructs the wrist extension drive group to increase its output to raise the tension to the desired value based on this tension deviation. Simultaneously, the control unit adjusts the output of the wrist flexion drive group to maintain antagonistic balance. During adjustment, a pressure sensor located between the distal radius and the lunate bone simultaneously detects an axial reaction force of 0.8N generated by the contact between the lens and the base. This value is within the safe threshold range, and the control system determines that the current load allows the installation operation to continue. After comprehensively calculating the angle and tension deviations, the control unit generates the drive signal adjustment amount for each flexible drive unit, adjusting the outputs of the wrist extension drive group, wrist flexion drive group, and ulnar deviation drive group respectively. This ensures that the dorsiflexion angle of the bionic wrist is precisely restored to 15°, the radial deviation angle is precisely converged to 8°, and the tension of each bionic tendon is restored to the target antagonistic balance state. During this closed-loop adjustment process, the output force of each drive group is precisely controlled within the desired range due to the real-time feedback from the tension sensor. This prevents the bionic wrist from impacting the microlens due to instantaneous over-force when adjusting its posture, thus avoiding squeezing damage to the lens edge. Simultaneously, as the bionic hand carrying the lens gradually approaches the lens mount, if the lens edge makes slight contact with the lens mount hole wall due to alignment deviation, generating additional axial resistance, this resistance is transmitted through the bionic wrist bone to the area between the distal end of the bionic radius and the bionic lunate. The pressure sensor immediately detects the abnormal increase in axial load (e.g., from 0.8N to 1.5N). Upon detecting this increase, the control system immediately adjusts the direction of the bionic wrist's movement speed, causing the bionic wrist to slightly adjust its posture along the direction of least resistance to complete automatic alignment. This avoids the risk of lens breakage or scratches caused by forced insertion.Ultimately, throughout the lens assembly process, the three types of sensors in the multimodal sensing system work together: the angle sensor ensures the bionic wrist reaches the target position with a precise posture, the tension sensor ensures the output force of each drive group is smooth and balanced, and the pressure sensor ensures that the contact force remains within a safe and controllable range during installation. Together, these three sensors guarantee high precision, high success rate, and high safety in the assembly of the micro-optical lens. Furthermore, in subsequent lens position fine-tuning processes, if the bionic wrist needs to maintain a suspended posture for an extended period (e.g., for several seconds while waiting for the adhesive to cure), the multimodal sensing system, through continuous closed-loop feedback from the angle and tension sensors, enables the bionic wrist to counteract pose drift caused by its own weight and minor external vibrations. This ensures the lens maintains a precise position throughout the adhesive curing process, significantly improving the yield and consistency of the micro-assembly process.

[0101] According to one embodiment of this application, the closed-loop control loop includes:

[0102] The adaptive impedance adjustment module is configured to calculate the joint spatial pose deviation based on the actual joint angle feedback from the angle sensor, and adjust the pulse parameter combination of the pulse drive signal applied to each flexible drive unit 4 in real time according to the rate and direction of change of the pose deviation, so as to achieve adaptive adjustment of the joint impedance. The pulse parameter combination includes at least the pulse bias level, pulse amplitude, pulse duty cycle, and pulse frequency. Existing technologies typically adjust only a single parameter (such as voltage amplitude). This solution achieves comprehensive control of the flexible drive unit 4 by combining and adjusting the bias level (maintaining preload), amplitude (providing driving force), duty cycle (adjusting average power), and frequency (adjusting response bandwidth).

[0103] In one implementation, the adaptive impedance adjustment module first receives the actual joint angles (including flexion / extension angles, radial / ulnar deviation angles, and pronation / supination angles) of the bionic wrist joint in each degree of freedom direction from the angle sensor in real time, and compares the actual angles with the preset desired joint angles to calculate the joint spatial pose deviation (i.e., pose error vector). Subsequently, the module performs time differentiation on the pose deviation to calculate its rate of change (i.e., joint angular velocity deviation) and determines the direction of the deviation (i.e., the sign of the deviation, indicating whether the joint deviates in a positive or negative direction). Based on the aforementioned pose deviation, deviation rate of change, and deviation direction, this module determines the required impedance adjustment amount for each flexible drive unit according to a preset adaptive adjustment law (such as PD control law, fuzzy control law, or control law based on impedance model), and converts it into adjustment instructions for the pulse parameter combination of the pulse drive signal. The pulse parameter combination includes at least the pulse bias level, pulse amplitude, pulse duty cycle, and pulse frequency. The pulse bias level refers to the DC bias voltage component superimposed in the pulse signal, and its amplitude determines the static pre-stretching degree of the dielectric elastomer film, thereby determining the intrinsic stiffness base value of each flexible drive unit. The pulse amplitude refers to the peak voltage of the high-level pulse signal, and its magnitude determines the peak electric field intensity per unit time of each flexible drive unit, thereby affecting the maximum output force. The pulse duty cycle refers to the proportion of the high-level duration to the pulse period, and its magnitude determines the average charge injection amount per unit time of each flexible drive unit, thereby affecting the average output force. The pulse frequency refers to the repetition frequency of the pulse signal, and its magnitude affects the dynamic response bandwidth and viscoelastic damping characteristics of each flexible drive unit. The adaptive impedance adjustment module adjusts the four pulse parameters based on the calculated impedance adjustment amount. For example, when the pose deviation increases and the rate of change of deviation increases, it indicates that the joint is deviating from the target pose and is still accelerating away. In this case, the equivalent stiffness of the joint needs to be increased to generate a greater restoring force. The module correspondingly increases the pulse bias level and pulse duty cycle to increase the intrinsic stiffness and average output force of each flexible drive unit. When the pose deviation decreases and the rate of change of deviation approaches zero, it indicates that the joint is approaching the target pose. In this case, the equivalent stiffness of the joint needs to be reduced to avoid overshoot and oscillation. The module correspondingly reduces the pulse bias level and pulse duty cycle to reduce the intrinsic stiffness and average output force of the drive unit. At the same time, when the direction of the pose deviation changes rapidly, it indicates that the joint is in a high-frequency vibration state. The module correspondingly increases the pulse frequency to increase the equivalent damping of the dielectric elastomer film, and adjusts the combination of pulse amplitude and duty cycle to make the drive unit output a damping force opposite to the vibration phase, thereby quickly suppressing oscillation. The aforementioned adaptive impedance adjustment process continues during the movement of the bionic wrist joint. That is, in each control cycle, the angle sensor updates the actual joint angle in real time, the adaptive impedance adjustment module recalculates the pose deviation and its rate of change, dynamically adjusts the pulse parameter combination and applies it to each flexible drive unit, thereby forming a continuous real-time closed-loop adjustment.The aforementioned structure, along with the adaptive impedance adjustment module that adjusts the pulse bias level in real time based on pose deviation and its rate of change, achieves direct physical modulation of the intrinsic stiffness of the dielectric elastomer drive unit. Increasing the bias level compresses the dielectric elastomer film more tightly in the thickness direction, significantly increasing its axial stiffness; conversely, decreasing the bias level relaxes the film, reducing its axial stiffness. This stiffness adjustment can be completed within microseconds without requiring additional variable stiffness mechanical structures or adjustment elements, avoiding the complex structure and response delay of traditional mechanical stiffness adjustment devices. This allows the bionic wrist to adapt to changes in the external environment and operational tasks with extremely high response speed. By using pulse amplitude and pulse duty cycle as independent adjustment parameters, decoupled control of the maximum and average output forces of the flexible drive unit is achieved. The pulse amplitude determines the instantaneous peak force, and the pulse duty cycle determines the cumulative effect of force per unit time. Their combined effect allows the drive unit to change the peak force while maintaining the average force (i.e., changing the pulse characteristics of the force), or to maintain the peak force while... By adjusting the average force under different conditions, the bionic wrist can be equipped with a wider range of force output modes to adapt to different movement requirements. By using the pulse frequency as an independent damping adjustment parameter and taking advantage of the physical properties of dielectric elastomer materials exhibiting different viscoelastic responses under electric field excitation at different frequencies, frequency-dependent adjustment of the damping characteristics of the bionic wrist joint is achieved. That is, high damping is provided during low-frequency vibration to quickly suppress large disturbances, and damping is reduced during high-frequency micro-vibration to ensure flexibility. This achieves optimal matching of stiffness and damping across the entire frequency range, significantly improving the motion stability and anti-disturbance capability of the bionic wrist joint. Through the coordinated adjustment of four pulse parameters, the bionic wrist joint can achieve independent decoupled adjustment of stiffness and damping within a unified pulse drive framework. That is, stiffness is adjusted by pulse bias level, damping is adjusted by pulse frequency, and force / displacement balance is adjusted by pulse amplitude and duty cycle. This overcomes the inherent defects of coupled stiffness and damping adjustment in traditional rigid drive systems, enabling the bionic wrist to respond to changes in the external environment with optimal impedance characteristics at different operation stages.

[0104] For example, the bionic wrist needs to lift the end cap vertically from above the feeding platform with high stiffness; secondly, during the process of moving the end cap towards the reducer housing, the bionic wrist needs to switch to medium stiffness to maintain posture stability; finally, during the process of aligning the end cap with the housing end face and pressing it in, the bionic wrist needs to switch to low stiffness mode to accommodate the alignment deviation between the end cap and the housing, avoiding the end cap from getting stuck or scratching the sealing surface due to rigid alignment. In the above three-stage operation, the adaptive impedance adjustment module adjusts the parameter combination of the pulse drive signal in real time: when the first stage (vertical lifting of the end cap) is started, the actual joint angle fed back by the angle sensor is basically consistent with the expected angle, and the posture deviation is zero. However, at the moment the end cap is lifted, due to the sudden loading of the end cap's gravity onto the bionic wrist, an instantaneous wrist joint drooping posture deviation of about 1.5° is generated. The adaptive impedance adjustment module detects the sudden appearance of the posture deviation and the increasing rate of change of the deviation (in the drooping direction), and immediately adjusts the wrist joint according to the preset control law. The pulse bias level of the wrist extension drive group is increased from 150V to 280V (to increase its intrinsic stiffness to counteract the load), the pulse amplitude is increased from 800V to 1000V (to provide sufficient peak force to overcome gravity), and the pulse duty cycle is increased from 30% to 55% (to increase the average output force). At the same time, the pulse frequency is set to 120Hz (a higher frequency to obtain a fast response). The combined effect of these three parameters enables the wrist extension drive group to pull the wrist joint back to the desired balance position within about 40ms, completing the stable lifting of the end cap. When entering the second stage (moving the end cap towards the housing), the posture deviation has converged to within 0.2° and the rate of change of deviation is close to zero. The adaptive impedance adjustment module determines that the joint is stable and then automatically reduces the pulse bias level of the wrist extension drive group to 200V (reducing the stiffness to a medium level to reduce motion energy consumption caused by excessive stiffness), and reduces the pulse amplitude to 850V and the duty cycle to 40%, so that the bionic wrist can move with lower mechanical impedance while maintaining posture stability, thereby reducing the energy consumption of each drive group.When entering the third stage (end cap aligned with and pressed into the housing end face), the contact force generated between the end cap sealing ring and the housing end face is transmitted to the bionic wrist joint through the bionic hand. The angle sensor detects a slight passive deflection of about 0.8° in the bionic wrist joint under the action of the contact force (caused by the non-uniform compression of the end cap sealing ring). The direction of this positional deviation changes twice at the moment of contact (-0.3°→+0.2°→-0.7°), indicating that the end cap is undergoing adaptive alignment adjustment with the housing end face. After detecting this alternating positional deviation, the adaptive impedance adjustment module determines that the joint stiffness needs to be reduced to conform to the natural alignment process of the end cap. It immediately instructs to significantly reduce the pulse bias level of each drive group from 200V to 120V (significantly reducing the voltage). (Low intrinsic stiffness), and to improve anti-oscillation capability, the pulse frequency is increased from 120Hz to 300Hz (increasing viscoelastic damping to absorb impact oscillations during alignment), and the pulse amplitude is maintained at 900V with the duty cycle adjusted to 35%. This allows the bionic wrist joint to respond to the contact force between the end cap and the housing in a compliant mode with low stiffness and high damping. Under the compliant support of the bionic wrist, the end cap automatically slides into the correct position along the end face of the housing. The adaptive impedance adjustment module continuously monitors the positional deviation and its rate of change during the pressing process. When the end cap is fully in place, the positional deviation converges back to near zero. The module determines that the pressing is complete and automatically increases the pulse bias level to 250V again to restore the high stiffness holding mode, ensuring that the end cap maintains a precise position in subsequent fastening processes. Throughout the three-stage operation described above, the adaptive impedance adjustment module requires no manual intervention. It autonomously completes three stiffness switches and dynamic adjustments to the pulse parameter combinations based entirely on the rate and direction of change of the actual joint angle and posture deviation fed back by the angle sensor. This allows the same bionic wrist to operate with optimal impedance characteristics in three operations with different impedance requirements: lifting, moving, and pressing. If a traditional rigid drive system were used, achieving the different stiffness requirements of the three stages would require a mechanical stiffness switching device or a complex force / position switching control strategy. This not only results in complex structures and delayed switching responses but also makes it difficult to provide the continuous compliance required for end cap alignment during the pressing stage. In contrast, this invention, through the adaptive impedance adjustment module's joint real-time adjustment of pulse bias level, pulse amplitude, pulse duty cycle, and pulse frequency, smoothly achieves a complete impedance switch from high stiffness to medium stiffness, then to low stiffness, and finally back to high stiffness within the same drive system and control framework. The response speed is fast, and the switching process is continuous and shock-free, significantly improving the success rate and task adaptability of the bionic wrist in multi-stage complex assembly tasks, while effectively protecting the operated workpiece from rigid impact damage.

[0105] According to one embodiment of this application, the closed-loop control loop further includes: a force and displacement coordinated allocation module, configured to receive the actual tendon tension of each flexible drive unit 4 fed back by the tendon tension sensor, and calculate the target pulse duty cycle and target pulse amplitude required by each flexible drive unit 4 according to the preset desired deformation ratio and the stiffness and damping adjustment amount output by the adaptive impedance adjustment module; wherein, the target pulse duty cycle and target pulse amplitude jointly determine the matching relationship between the desired deformation and the desired output force of each flexible drive unit 4; the force and displacement coordinated allocation module also allocates complementary pulse duty cycles to different flexible drive units 4 in the same antagonistic pair according to the coordinated coupling relationship between each antagonistic drive group, so that both sides of the antagonistic pair maintain active tension within the preset neighborhood of the joint equilibrium position, so as to achieve zero-position stiffness and anti-disturbance capability of the joint.

[0106] In one implementation, the force and displacement coordination distribution module first receives three types of input information: the first is the actual tendon tension value of each flexible drive unit, which is fed back in real time by the tendon tension sensor. This value reflects the real-time tensile state currently borne by each bionic tendon. The second is the preset expected deformation ratio, which is predetermined based on the expected motion task of the bionic wrist joint (for example, when the wrist joint is expected to perform palmar flexion, the expected deformation ratio of the wrist flexion drive group to the wrist extension drive group is 3:1, that is, the wrist flexion drive group needs to contract by 3 units of deformation while the wrist extension drive group needs to extend by 1 unit of deformation to generate a net palmar flexion torque; when the wrist flexion and radial deviation combined motion is expected to be performed simultaneously, the expected deformation ratio between the wrist flexion drive group, wrist extension drive group, wrist radial deviation drive group, and wrist ulnar deviation drive group is jointly determined according to the motion components on each degree of freedom according to the kinematic distribution matrix). The third is the stiffness and damping adjustment amount output by the adaptive impedance adjustment module, which determines the equivalent stiffness and damping characteristics that the bionic wrist joint should exhibit in the current motion state. The force and displacement coordinated allocation module comprehensively calculates the above three aspects of information: First, it determines the target deformation ratio of each flexible drive unit based on the desired deformation ratio. Then, it determines the target output force level that each flexible drive unit needs to provide based on the stiffness and damping adjustment (the stiffness adjustment determines the ratio between position deviation and restoring force, and the damping adjustment determines the ratio between velocity deviation and damping force; the sum of these two determines the total target force that each drive unit needs to provide under the current pose and velocity deviations). Next, using the actual tendineae tension of each drive unit as feedback, it calculates the deviation between the actual tension and the target output force and converts this deviation into an adjustment amount for the drive parameters. Finally, based on the combined requirements of the target deformation and target output force of each drive unit, the module calculates the required output force level for each flexible drive unit. The target pulse duty cycle and target pulse amplitude are used to determine the desired deformation and force control. The target pulse duty cycle mainly controls the average charge injection amount per unit time of each drive unit, thereby controlling its average output force and average deformation. The target pulse amplitude mainly controls the instantaneous peak electric field intensity of each drive unit, thereby controlling its peak output force and maximum deformation. Together, they determine the matching relationship between the desired deformation and desired output force of each flexible drive unit. That is, the same drive unit can achieve the same deformation but different output forces under different load conditions through different duty cycle-amplitude combinations (high duty cycle + low amplitude can achieve large deformation but small force output, suitable for fast movement but light load scenarios; low duty cycle + high amplitude can achieve small deformation but large force output, suitable for precision positioning but heavy load scenarios), thereby achieving decoupling of deformation control and force control.Based on this, the force and displacement coordination allocation module further allocates complementary pulse duty cycles to different flexible drive units in the same antagonistic pair according to the coordinated coupling relationship between the antagonistic drive groups (i.e., the kinematic complementarity between the two drive groups in the antagonistic pair, for example, the wrist flexion drive group and the wrist extension drive group generate torques in opposite directions around the same rotation axis): Specifically, when the target pulse duty cycle of the wrist flexion drive group is D_flexor, the target pulse duty cycle of the wrist extension drive group is set to D_extensor = D_base - D_flexor + D_bias, where D_base The baseline duty cycle is 50%, and D_bias is the bias determined based on the stiffness adjustment. When joint stiffness needs to be increased, D_bias is increased, which increases the sum of the duty cycles of the two opposing forces, thus maintaining higher active tension for both. When joint stiffness needs to be decreased, D_bias is decreased, which decreases the sum of the duty cycles of the two opposing forces, thus maintaining lower active tension for both. The difference between D_flexor and D_extensor determines the direction and magnitude of the net output torque of the joint, while the sum of D_flexor and D_extensor determines the active stiffness and disturbance resistance of the joint. Through the aforementioned complementary pulse duty cycle allocation strategy, within the preset neighborhood of the joint's equilibrium position (i.e., the deviation between the actual pose and the desired pose is within a preset threshold range, such as a small neighborhood with an angle deviation of less than ±2°), both the wrist flexion drive group and the wrist extension drive group maintain non-zero active tension. This ensures that the bionic wrist joint always has a definite zero-position stiffness and anti-disturbance capability near the equilibrium position. When an external disturbance attempts to pull the joint away from the equilibrium position, the tension of one drive group increases while the tension of the other drive group decreases. The difference between the two generates a restoring torque that resists the disturbance, and the magnitude of the restoring torque increases linearly with the increase of the deviation distance (similar to the linear restoring force characteristic of a spring), thereby effectively suppressing the influence of external disturbances on the joint's pose.The aforementioned structure, through a force and displacement collaborative allocation module, jointly converts the desired deformation ratio and stiffness / damping adjustment into the target pulse duty cycle and pulse amplitude, effectively decoupling the "deformation-force" coupling characteristics of the dielectric elastomer flexible actuation unit. Even within the same flexible actuation unit, the deformation (through a combination of duty cycle and amplitude) and output force (through deviation correction with the target force via tension feedback) can be adjusted separately according to task requirements. This solves the technical challenge of strong coupling and difficulty in independent control of deformation and output force in traditional DEA actuation, significantly improving the motion control accuracy and adaptability of the bionic wrist under different load conditions. By allocating complementary pulse duty cycles to different flexible actuation units within the same antagonistic pair, both antagonistic pairs maintain an active contraction state near the joint equilibrium position (rather than one being completely relaxed). This achieves independent adjustment of the joint's zero-position stiffness (joint stiffness can be changed by adjusting the offset of the complementary duty cycle without altering the joint's equilibrium position) and enables the joint to respond quickly and generate restoring force when subjected to external disturbances, significantly improving the bionic wrist joint. The improved anti-disturbance capability and positional accuracy effectively avoid joint degree of freedom issues or response delays caused by drive unit slack. The coordinated setting of the target pulse duty cycle and target pulse amplitude allows each flexible drive unit to flexibly adjust its operating point according to different matching requirements of desired deformation and desired output force. When rapid movement is required, a high duty cycle + low amplitude mode is selected to obtain large deformation and fast response; when precise force control is required, a low duty cycle + high amplitude mode is selected to obtain small deformation and large output force; and when energy-saving standby is required, a low duty cycle + low amplitude mode is selected to reduce energy consumption. This multi-mode operating point adjustment capability enables the bionic wrist to adaptively switch to the optimal drive mode at different operation stages, significantly improving energy utilization efficiency and task adaptability. The existence of the force and displacement coordinated distribution module means that the impedance control of the bionic wrist no longer relies on complex mechanical variable stiffness mechanisms or external force sensors, but can achieve continuous adjustment of joint stiffness and damping entirely through algorithm-level adjustment of pulse duty cycle and amplitude. The structure is simplified, the response is fast, and there is no mechanical wear, which greatly improves the reliability and service life of the system.

[0107] According to one embodiment of this application, the electro-actuated flexible-drive bionic wrist further includes a bionic wrist joint capsule. The bionic wrist joint capsule is made of a flexible sealing material and covers the outside of the bionic distal radius 11, the bionic intercarpal joint, and the bionic carpal metacarpophalangeal joint. The bionic wrist joint capsule is filled with a lubricating medium. The flexible-sealed bionic wrist joint capsule can completely cover the joint structure, preventing external dust, sweat, and foreign objects from entering the interior of the joint structure, thus improving the reliability and durability of the device in a human-like operating environment. The lubricating medium filled inside the joint capsule can form a continuous lubricating film when the components move relative to each other, significantly reducing the frictional resistance between the joint contact surface and the flexible drive unit 4, making multi-degree-of-freedom movements such as pitch, lateral bending, and rotation smoother and more compliant, and closer to the natural movement characteristics of the human wrist joint.

[0108] Specifically, a bionic wrist joint capsule is a protective structure that mimics a biological joint capsule. It can be molded in one piece, for example, through injection molding or 3D printing technology, to form an integral structure that can completely cover all bionic joints; or it can be composed of multiple flexible segments connected by a seal to adapt to complex joint movements.

[0109] Flexible sealing materials are crucial for ensuring the functionality of the bionic wrist joint capsule. These materials must possess excellent elasticity, flexibility, and sealing performance to deform without mechanical interference during multi-degree-of-freedom movements of the bionic joint and maintain a continuous internal seal. Optionally, high-performance elastomers such as medical-grade silicone rubber, thermoplastic polyurethane (TPU), or fluororubber can be used as flexible sealing materials, as these materials exhibit good wear resistance, fatigue resistance, and chemical corrosion resistance. Alternatively, composite materials can be employed, such as embedding high-strength fibers within an elastomer matrix, to further enhance tear resistance and durability.

[0110] In one embodiment, the biomimetic tendon chord is equipped with a flexible sensor array. A flexible sensor array is a collection of multiple flexible sensor units capable of conforming to irregular surfaces and sensing various physical quantities, such as pressure, strain, and friction. Its function is to acquire the tension distribution and sliding resistance data of the biomimetic tendon chord in real time and non-invasively. The flexible sensor array can employ piezoresistive or piezoelectric sensor units, fabricated by embedding conductive materials (such as carbon nanotubes, graphene, or conductive polymers) into a flexible substrate (such as polyimide or PDMS). When pressure is applied to the tendon chord or it deforms, the resistance or charge of the sensor units changes, thereby reflecting the tension or sliding state of the tendon chord. Alternatively, the flexible sensor array can also employ fiber Bragg grating (FBG) sensors, integrating multiple FBG sensors on a flexible substrate. By monitoring changes in the wavelength of reflected light in the optical fiber, the strain of the tendon chord is sensed, and the tension is calculated.

[0111] Monitoring the tension distribution of bionic tendons aims to obtain the force conditions along their length or in different drive groups, ensuring coordinated operation of each drive group and avoiding local overload or underload. Flexible sensor arrays can be arranged along the length of the bionic tendon or at the connection point between the tendon and the bionic bone structure. Multiple sensor units simultaneously measure strain or pressure at different points to construct a tension distribution map of the tendon. Alternatively, the flexible sensor array can be integrated into the surface or interior of the bionic tendon, using distributed sensing technology to acquire real-time dynamic tension changes during movement and transmit the data to the control system for analysis.

[0112] Monitoring chordae tendineae sliding resistance aims to assess the smoothness of movement of bionic chordae tendineae within chordae tendineae channels or sheaths, and to promptly detect problems such as jamming, excessive friction, or lubrication failure. A flexible sensor array can be integrated onto the contact surface between the bionic chordae tendineae and the chordae tendineae channel, measuring the shear force or friction generated during chordae tendineae sliding to assess sliding resistance. Alternatively, the flexible sensor array can be positioned on the inner wall of the chordae tendineae channel; as the chordae tendineae slides, the sensor array can sense minute deformations or pressure changes between the chordae tendineae and the channel wall, thus indirectly reflecting the magnitude of the sliding resistance.

[0113] By connecting a flexible sensor array to a bionic tendon chord using the above technical solution, real-time and precise monitoring of the tension distribution and sliding resistance of the bionic tendon chord is achieved. When the bionic tendon chord drives the bionic joint movement, the flexible sensor array can closely adhere to the surface of the tendon chord, sensing its stress state and friction with the surrounding environment in real time. By monitoring the tension distribution, the control system can obtain precise load information for each drive group, thereby enabling refined torque control and motion planning, effectively avoiding the decrease in joint movement accuracy caused by uneven tension. Simultaneously, monitoring the sliding resistance of the tendon chord can promptly detect abnormalities such as jamming, wear, or insufficient lubrication of the tendon chord in the bionic carpal tunnel structure 7 or the bionic tendon sheath, thus providing early warning of potential mechanical failures, extending the service life of the bionic tendon chord, and ensuring the long-term stable operation of the electrically actuated flexible-driven bionic wrist in complex working environments. This closed-loop feedback mechanism significantly improves the reliability, motion accuracy, and durability of the electrically actuated flexible-driven bionic wrist.

[0114] This application also proposes a biomimetic robot, including any of the aforementioned electro-actuated flexible-drive biomimetic wrists. A robot is an automated machine capable of performing tasks autonomously or semi-autonomously, typically composed of a mechanical structure, a drive mechanism, sensors, and a control system. Its mechanical structure can be serial, parallel, or hybrid; the drive mechanism can be a motor, hydraulic, or pneumatic system; sensors are used to perceive the environment and its own state; and the control system is responsible for planning motion, executing tasks, and processing feedback information. Robots can be designed in various forms, such as industrial robots, service robots, medical robots, collaborative robots, or humanoid robots, depending on their application scenarios and functional requirements.

[0115] By incorporating the aforementioned electro-actuated flexible bionic wrist as a core component of the robot's end effector, a deep integration of biological principles and mechanical structure is achieved. Through the integration of bionic distal radius joints, bionic intercarpal joints, and bionic carpal metacarpophalangeal joints, coupled with independent chordae tendineae actuation units, the robot achieves a degree of freedom and compliance approaching that of the human wrist. Applying the electro-actuated flexible bionic wrist to the robot allows it to overcome the physical limitations of traditional rigid serial structures, achieving full-posture accessibility in unstructured environments through tension adjustment of bionic chordae tendineae and multi-joint coordination. This integration not only endows the robot with stronger environmental adaptability but also ensures the motion accuracy and stability of the mechanism when performing complex tasks through auxiliary structures such as bionic tendon sheaths, flexible sensor arrays, and lubricating media. By introducing the electro-actuated flexible bionic wrist as a whole functional unit into the robot, the problems of limited operating space and lack of compliance in complex operations are solved, providing a hardware foundation for achieving highly dexterous robot operations.

[0116] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electrically actuated flexible bionic wrist, characterized in that, include: A bionic wrist bone system includes a proximal bionic bone component and a distal bionic bone component. The proximal and distal bionic bone components are connected by a bionic wrist joint to form a multi-degree-of-freedom wrist joint complex with flexion-extension, radial and ulnar deviation, and pronation and supination degrees of freedom. Multiple independent flexible drive units, including at least the following drive groups: Wrist flexion drive assembly, used to provide palmar flexion power to the wrist joint; Wrist extension drive assembly, used to provide wrist dorsiflexion power; The radial deviation drive group is used to provide radial deviation swing force for the wrist joint; Ulnar deviation drive assembly, used to provide ulnar deviation swing force for the wrist joint; Pronation drive assembly, used to provide forearm pronation power; Supination drive assembly, used to provide forearm supination power; The flexible drive unit is composed of an electro-actuated functional component, which includes a solid electro-actuated material or an electro-hydraulic conversion unit. The electro-actuated functional component is capable of active deformation under electric field excitation, and its deformation behavior under electric field excitation is at least anisotropic. The wrist flexion drive group and the wrist extension drive group are arranged in antagonistic arrangement, the radial deviation drive group and the ulnar deviation drive group are arranged in antagonistic arrangement, and the pronation drive group and the supination drive group are arranged in antagonistic arrangement. The bionic tendon cable transmission system includes multiple bionic tendons. One end of each bionic tendon cable is fixedly connected to the output end of the corresponding flexible drive unit, and the other end is connected to the proximal or distal bionic bone component through a bionic attachment point, so as to transmit the driving force to the multi-degree-of-freedom wrist joint complex through the bionic tendon cable. A bionic tendon sheath and trochlear system includes multiple bionic tendon sheath and trochlear structures disposed on the proximal and distal bionic bone components for constraining and guiding the movement path of the bionic tendon chordae.

2. The electro-actuated flexible actuated bionic wrist according to claim 1, characterized in that, The proximal bionic skeletal component includes a bionic distal radius and a bionic distal ulna, and the distal bionic skeletal component includes at least one bionic wrist bone; the bionic distal radius and the bionic distal ulna are movably connected by a bionic distal radioulnar joint, and the bionic wrist bone is movably connected to the bionic distal radius, the bionic distal ulna, and the hand skeletal component, respectively.

3. The electro-actuated flexible actuated bionic wrist according to claim 2, characterized in that, The biomimetic distal radioulnar joint includes a biomimetic triangular fibrocartilage complex; the biomimetic triangular fibrocartilage complex is made of a flexible elastomer material, with its proximal end fixed to the distal end of the biomimetic ulna and its distal end attached to the ulnar notch of the distal end of the biomimetic radius; the biomimetic triangular fibrocartilage complex is used to provide elastic restraint and axial cushioning during wrist rotation and lateral swing, and to maintain the stability of the distal radioulnar joint.

4. The electro-actuated flexible actuated bionic wrist according to claim 1, characterized in that, The bionic tendons of the pronation drive group and the supination drive group are arranged in a cross-spiral manner on the bionic forearm: the bionic tendons of the pronation drive group start from the ulnar side of the distal end of the bionic ulna and cross obliquely to the palmar side of the distal end of the bionic radius; the bionic tendons of the supination drive group start from the palmar side of the distal end of the bionic radius and cross obliquely to the dorsal side of the distal end of the bionic ulna; the bionic tendon sheath and trochlear system includes cross-guided trochlears respectively set on the radius and ulna to limit the radial displacement of the bionic tendons during rotation.

5. The electro-actuated flexible actuated bionic wrist according to claim 1, characterized in that, It also includes a bionic carpal tunnel structure for accommodating and guiding bionic tendineae and neurovascular bundles passing through the wrist joint.

6. The electro-actuated flexible actuated bionic wrist according to claim 5, characterized in that, The bionic carpal tunnel structure is internally divided into multiple independent tendon channels, including flexor tendon channels and neurovascular simulated bundle channels; the flexor tendon channels are lined with a low-friction coating; the neurovascular simulated bundle channels are used to arrange bionic nerves or bionic blood vessels.

7. The electro-actuated flexible actuated bionic wrist according to claim 5 or 6, characterized in that, It also includes a multimodal wrist sensing system, which comprises: Capacitive or resistive pressure sensors are placed between the distal end of the bionic radius and the bionic lunate to detect axial loads on the wrist joint. Angle sensors, respectively installed at the distal radioulnar joint and the radiocarpal joint, are used to detect the wrist flexion-extension angle, radial / ulnar deviation angle, and forearm pronation / supination angle. The tendon tension sensor installed in the bionic carpal tunnel structure is used to monitor the tendon tension of each drive unit in real time. The angle sensor and tension sensor, together with the flexible drive unit, form a closed-loop control circuit to achieve coordinated control and impedance regulation of antagonistic muscle groups in compound motion.

8. The electro-actuated flexible actuated bionic wrist according to claim 7, characterized in that, The closed-loop control circuit includes: The adaptive impedance adjustment module is configured to calculate the joint spatial pose deviation based on the actual joint angle fed back by the angle sensor, and adjust the pulse parameter combination of the pulse drive signal applied to each flexible drive unit in real time according to the rate of change and direction of the pose deviation, so as to achieve adaptive adjustment of joint impedance. The pulse parameter combination includes at least the pulse bias level, pulse amplitude, pulse duty cycle, and pulse frequency.

9. The electro-actuated flexible actuated bionic wrist according to claim 8, characterized in that, The closed-loop control circuit also includes: The force and displacement coordination distribution module is configured to receive the actual tendon tension of each flexible drive unit fed back by the tendon tension sensor, and calculate the target pulse duty cycle and target pulse amplitude required by each flexible drive unit according to the preset desired deformation ratio and the stiffness and damping adjustment amount output by the adaptive impedance adjustment module. The target pulse duty cycle and the target pulse amplitude together determine the matching relationship between the desired deformation and the desired output force of each flexible drive unit. The force and displacement coordination distribution module also allocates complementary pulse duty cycles to different flexible drive units in the same antagonistic pair according to the coordinated coupling relationship between the drive groups arranged in each antagonistic arrangement, so that both sides of the antagonistic pair maintain active tension within the preset neighborhood of the joint balance position, so as to achieve zero-position stiffness and anti-disturbance capability of the joint.

10. The electro-actuated flexible actuated bionic wrist according to claim 2, characterized in that, It also includes a bionic wrist joint capsule, which is made of a flexible sealing material and covers the outside of the bionic distal radius joint, the bionic intercarpal joint, and the bionic carpal metacarpal joint; the inside of the bionic wrist joint capsule is filled with a lubricating medium.

11. A biomimetic robot, characterized in that: Including the electrically actuated flexible-drive bionic wrist as described in any one of claims 1-10.

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