Variable resistance force feedback hand exoskeleton system and control method

Abstract

The invention relates to a variable resistance force feedback hand exoskeleton system and a control method thereof. The system comprises a thumb base which comprises a thumb fixing support used for fixing the thumb, a plurality of shaft rod fixing bases rigidly connected with the thumb fixing support and a posture sensor used for obtaining the overall relative posture of the hand. The system further comprises a plurality of finger tip moving resistance mechanisms, and each finger tip moving resistance mechanism comprises a shaft rod, a finger tip moving resistance mechanism, a finger tip moving resistance mechanism, a finger tip moving resistance mechanism and a finger tip moving resistance mechanism, wherein the lower end of the shaft rod is rotationally hinged to a corresponding shaft rod fixing base on the thumb base; the finger tip main body is arranged on the shaft rod in a sliding manner; the finger fixing ring is fixed on the finger tip main body and is used for fixing fingertips of an index finger, a middle finger, a ring finger or a little finger; the variable resistance assembly is arranged on the finger tip main body and is used for extruding the shaft rod to generate variable resistance; the position sensor is fixed to the finger tip body and used for detecting the position of the finger tip body relative to the shaft rod in real time. According to the technical scheme, the hand motion freedom degree and the resistance feedback authenticity in virtual reality interaction can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of virtual reality human-computer interaction, and in particular to a variable resistance force feedback hand exoskeleton system and a control method thereof. Background Art

[0002] As the body's most sophisticated motor organ, the hand's tactile feedback capabilities crucially impact the realism of virtual environment interactions. Currently, mainstream hand interaction devices fall into three main categories: data gloves use flexible sensors to capture finger bending angles but fail to provide mechanical feedback; mechanical exoskeletons employ rigid linkage structures, which, while capable of generating resistance, suffer from uneven weight distribution and limited freedom of movement; and traditional force feedback devices, which often utilize direct motor drive, resulting in bulky systems and delayed response times. These devices commonly suffer from technical flaws that interfere with natural user gestures and tactile realism.

[0003] Amid the rapid development of virtual reality technology, existing input devices remain at the level of traditional controllers, failing to achieve a mechanical interaction experience equivalent to the real world. Commercial exoskeleton systems, in particular, face two significant challenges when simulating grasping movements: first, the complex transmission mechanism concentrates the weight of the device on the wrist, compromising comfort during extended use; second, the fixed linkage design restricts the lateral freedom of movement of the fingers, resulting in a noticeable "mechanical feel" when manipulating virtual objects. Furthermore, existing control methods rely on high-precision motion capture systems, resulting in complex data processing and incompatibility with lightweight hardware platforms.

[0004] More critically, traditional approaches to resistance simulation suffer from fundamental flaws: Using a constant damping coefficient results in feedback forces that mismatch the virtual object's properties, while achieving variable resistance through coordinated multi-motor control leads to significant power consumption increases and increased mechanical complexity. These technical bottlenecks severely hinder the naturalness and immersiveness of hand interaction in VR systems. Addressing these issues, existing technologies urgently need improvement. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a variable resistance force feedback hand exoskeleton system and a control method thereof, which has the advantages of improving the freedom of hand movement and the authenticity of resistance feedback in virtual reality interaction.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] The present application provides a variable resistance force feedback hand exoskeleton system, and the technical solution is as follows: A variable resistance force feedback hand exoskeleton system, comprising:

[0008] Thumb base, including:

[0009] o Thumb fixing support, used to fix the thumb;

[0010] oMultiple shaft fixed bases, rigidly connected to the thumb fixed support;

[0011] o Posture sensor, used to obtain the relative posture of the hand as a whole;

[0012] ●Multiple fingertip resistance mechanisms, each of which includes:

[0013] o Axis rod, the lower end of which is rotatably hinged to the corresponding shaft rod fixing base on the thumb base, and a limit block is provided at the upper end;

[0014] oThe fingertip body is slidably mounted on the shaft;

[0015] o Finger fixing ring, fixed on the fingertip body, used to fix the tip of the index finger, middle finger, ring finger or little finger;

[0016] o a variable resistance component, disposed on the fingertip body and used to squeeze the shaft to generate a variable resistance;

[0017] o Position sensor, fixed to the fingertip body, for detecting the position of the fingertip body relative to the shaft in real time.

[0018] This technical solution reduces system complexity through a modular design, while also combining dynamic resistance adjustment with multi-dimensional sensing to achieve precise force feedback. In the thumb base, a rigid connection between the thumb support and the shaft base simplifies the thumb support structure and ensures a stable connection between the thumb base and the fingertip dynamic resistance mechanism. The posture sensor is directly integrated into the shaft base, enabling direct capture of overall hand posture changes. In the fingertip dynamic resistance mechanism, the shaft, through a combination of a rotary hinge and a stopper, allows the fingers to slide on the shaft and rotate relative to the shaft base while also constraining their range of motion. The sliding fit between the fingertip body and the finger fixing ring allows independent movement and free rotation along the shaft, simulating the movement of fingers other than the thumb. The variable resistance component directly compresses the shaft to generate variable resistance, thereby suppressing the resistance during linear motion of the finger and applying a reaction force to the fingertip, thus achieving force feedback. A position sensor monitors the position of the fingertip body relative to the shaft in real time, mapping the physical displacement into motion parameters in the virtual environment and providing a data basis for dynamic resistance adjustment. The synergistic effect of various technical features ultimately achieves a balance between light weight, high degree of freedom and precise force feedback.

[0019] Furthermore, the present application also proposes that the position sensor is a laser ranging sensor, with its emitting end facing the limit block, and the relative position is calculated by measuring the distance between it and the limit block. This technical solution uses a laser ranging sensor as the core component of position detection to achieve high-precision non-contact measurement of the fingertip motion trajectory, ensuring that each movement of the exoskeleton can obtain accurate feedback. The laser emitting end is directly pointed at the limit block at the top of the shaft, and the absolute distance value between the fingertip body and the limit block is obtained in real time using the laser ranging principle. The linear displacement of the fingertip body along the shaft is converted through geometric relationships. Compared with traditional contact displacement sensors, the laser ranging method avoids the influence of mechanical wear on measurement accuracy. At the same time, a stable measurement reference is formed by the directionally emitted laser beam and the reflective surface of the limit block, effectively eliminating measurement interference that may occur in multi-degree-of-freedom motion. As a fixed reference object, the limit block not only assumes the mechanical limit function, but also provides a standard reflective surface for laser ranging, realizing the integrated design of the sensor mounting structure and the mechanical limit device, and simplifying the system complexity.

[0020] Furthermore, the present application proposes that the posture sensor be a multi-axis IMU posture sensor, mounted on a shaft-fixed base. This technical solution achieves high-precision dynamic detection of the hand's overall posture by directly integrating the multi-axis IMU posture sensor onto the shaft-fixed base. The multi-axis IMU posture sensor can simultaneously measure multi-dimensional posture parameters such as pitch angle and roll angle, significantly improving the capture dimension of hand motion posture compared to single-axis sensors.

[0021] Furthermore, the present application also proposes that the fingertip body is provided with a through hole that passes through the upper and lower end surfaces, and the shaft passes through the through hole; the fingertip body can be linearly lifted and lowered along the shaft and can rotate freely in the circumferential direction. This technical solution uses a through hole structure that passes through the upper and lower end surfaces to enable the shaft to pass through the fingertip body, forming a physical basis for sliding fit. The presence of the through hole makes it possible for the fingertip body to move linearly up and down on the shaft, which directly corresponds to the linear displacement requirements of the finger flexion and extension movements. At the same time, the clearance fit between the through hole and the shaft allows the fingertip body to rotate freely in the circumferential direction around the axis of the shaft. This rotational freedom corresponds to the lateral fine-tuning movement naturally generated by the finger during the grasping process. The combined motion mode of linear lifting and circumferential rotation breaks through the limitations of the traditional exoskeleton's single-direction movement, retaining the precise position control of the axial movement, and compensating for the multi-dimensional displacement requirements in the actual movement of the finger joints through the rotational freedom, thereby restoring the natural movement trajectory of the human finger while maintaining the accuracy of force feedback.

[0022] Furthermore, the present application proposes a thumb-fixing support connected to a rigid fixing plate with an arc-shaped outer contour, and a shaft fixing base mounted on the rigid fixing plate, with the shaft fixed perpendicular to each fingertip. This technical solution optimizes the force transmission path and wearability of the hand exoskeleton through the specifically designed rigid fixing plate and shaft layout. The arc-shaped rigid fixing plate is fitted to the physiological curve of the human thumb base, allowing it to fit tightly to the base of the thumb, avoiding the localized compression or displacement caused by shape mismatch in traditional rigid structures. The shaft fixing base is mounted on the rigid fixing plate, maintaining a perpendicular relationship between the shaft and each fingertip. This ensures that the direction of the resistance applied by the shaft aligns with the natural curvature of the fingers when the user grasps, thereby eliminating motion interference caused by deviations in the force feedback direction. This structural design not only ensures the exoskeleton's efficient force transmission during force feedback, but also reduces the foreign body sensation during wear through its ergonomically designed curved shape, achieving a balance between lightweight exoskeleton and freedom of movement.

[0023] Furthermore, the present application also proposes that the rigid fixing plate passes through the side hole of the thumb fixing support and is fixed by a rubber ring; the thumb fixing support is provided with a side hole for the thumb tie to pass through to adjust the length.

[0024] Furthermore, the present application also proposes that the variable resistance component includes:

[0025] ●Variable resistance block, which is movably set on the finger end body next to the shaft;

[0026] ●A driver is connected to the variable resistance block through a transmission structure; the driver drives the variable resistance block toward or away from the shaft, generating a linearly changing resistance through squeezing.

[0027] This technical solution achieves dynamic adjustment of finger movement resistance through the synergistic effect of a variable resistance block and a driver. The variable resistance block is flexibly positioned on the fingertip body next to the shaft, allowing its position to be flexibly adjusted according to driver commands, avoiding the motion interference of traditional rigid structures. The driver is connected to the variable resistance block via a transmission structure, precisely controlling its displacement and thereby varying the contact pressure between the variable resistance block and the shaft. By driving the variable resistance block linearly toward or away from the shaft, a continuous resistance change directly related to the hardness of the virtual object is generated. This not only maintains the structural stability of the shaft as a sliding guide but also enables stepless adjustment of the resistance level. The movable setting of the variable resistance block overcomes the limitations of traditional fixed resistance structures, enabling a continuous resistance adjustment range from free movement to fully locked. The coordination between the driver and transmission structure optimizes the mechanical transmission ratio, ensuring control accuracy while reducing the driver's power requirements.

[0028] Furthermore, the present application also proposes that the variable resistance block is hinged to the fingertip body, and its side facing the shaft is an outwardly convex curved surface covered with a flexible material; the driver drives the variable resistance block to rotate around the hinge axis to adjust the distance from the shaft. This technical solution achieves smooth resistance adjustment and comfortable human-computer interaction through the coordinated design of the articulated variable resistance block and the curved flexible contact structure. Specifically, the variable resistance block is hingedly connected to the fingertip body, allowing the variable resistance block to rotate around a fixed axis rather than linear displacement. This movement mode not only reduces the complexity of the drive mechanism, but also avoids the jamming phenomenon that may occur in linear motion. The contact surface of the variable resistance block adopts an outwardly convex curved surface shape and is covered with a flexible material, so that when the variable resistance block rotates close to the shaft, the curved surface structure can gradually increase the contact area. The purpose of the curve is to linearly control the contact area between the flexible material and the target plane, resulting in a continuous resistance change directly related to the hardness of the virtual object, and realizing stepless adjustment of the resistance size. The flexible material layer absorbs impact energy through elastic deformation and also exhibits a high coefficient of friction. This dual effect ensures that resistance increases linearly with displacement while effectively reducing the vibration and noise generated by rigid contact. The actuator precisely adjusts the distance from the shaft by controlling the rotation angle of the variable resistance block. This rotational adjustment method facilitates micro-distance control compared to linear propulsion, improving the resolution of resistance gradient changes. Furthermore, the tangential friction generated by the rotational motion is converted into normal pressure on the shaft, optimizing the mechanical transmission path.

[0029] Furthermore, the present application proposes that the variable resistance assembly also includes a slider and a connecting rod connecting the slider and the variable resistance block; the driver is a drive motor, whose output end is connected to a screw, and the slider meshes and sleeves with the screw to form a screw structure. This technical solution, by introducing a mechanical transmission structure of the slider and connecting rod, converts the rotational motion of the drive motor into linear displacement of the slider, thereby precisely controlling the degree of compression of the variable resistance block on the shaft. The screw structure formed by the meshing of the slider and screw has a self-locking characteristic, which can prevent displacement deviation caused by external force interference and ensure the stability of resistance adjustment. The design of directly connecting the output end of the drive motor to the screw simplifies the power transmission path and reduces energy loss in intermediate transmission components, making the position control of the variable resistance block faster and more accurate. The structure of the connecting rod connecting the slider and the variable resistance block converts linear thrust into the clamping action of the variable resistance block, achieving a mechanical force amplification effect, allowing even a small power motor to generate sufficient clamping force. The precise thread matching of the screw structure can achieve micron-level displacement resolution, thereby accurately matching the resistance gradient required for objects of different hardness in the virtual environment.

[0030] Furthermore, the present application also proposes a variable resistance force feedback hand exoskeleton control method, which uses the above system to perform:

[0031] (a) The distance between each fingertip and the thumb support is collected in real time by using a position sensor;

[0032] (b) Collecting the pitch and roll angles of the hand through the posture sensor;

[0033] (c) Controller execution:

[0034] Map distance values ​​to finger bending angles;

[0035] Perform Kalman filtering on the attitude data to extract stable angle information;

[0036] (d) synchronizing the bend angle, pitch angle, and roll angle outputted in step (c) to the hand model in the virtual environment;

[0037] (e) When any fingertip enters the collision range of an object in the virtual environment, a resistance control command is generated; the collision range is a tolerance zone formed by the object mesh face offset in the normal direction -mm;

[0038] (f) The corresponding actuator is driven according to the resistance control instruction, pushing the variable resistance block to squeeze the shaft to generate a resistance that is positively correlated with the hardness of the virtual object.

[0039] This technical solution integrates sensor data acquisition, data processing, virtual environment synchronization, and dynamic resistance feedback to form a closed-loop control loop. First, position sensors directly measure the dynamic distance between the fingertips and the thumb base, simplifying the complex model required for traditional hand flexion angle calculation. Attitude sensors collect pitch and roll angles, and combined with Kalman filtering to eliminate noise interference, ensure the stability of the overall hand posture. The controller maps the distance values ​​to flexion angles, eliminating the computational burden of multi-joint angle calculations. The filtered attitude data also enhances the motion coherence of the virtual hand model. The processed data is synchronized with the virtual environment, achieving low-latency matching between physical movements and the virtual model. The collision range is offset by the object mesh normal to create a tolerance zone, preventing false positives and improving collision detection accuracy. Resistance control commands dynamically adjust the driver output based on the hardness of the virtual object, ensuring that the pressure exerted by the variable resistance block on the shaft is linearly proportional to the object's hardness. This ensures that the resistance experienced by the user more closely matches the real-world physical characteristics of virtual interaction.

[0040] From the above, it can be seen that the variable resistance force feedback hand exoskeleton system and its control method provided by this application achieve dynamic resistance adjustment while maintaining natural hand movement through the synergistic effect of the sliding fingertip body and the variable resistance component, solving the problems of uneven weight distribution, limited freedom of movement, and mismatch between feedback force and virtual object properties in traditional equipment, and has the advantage of improving the authenticity of virtual reality interaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a three-dimensional schematic diagram of the variable resistance force feedback hand exoskeleton system provided by the present invention.

[0042] Figure 2 A frontal schematic diagram of the variable resistance force feedback hand exoskeleton system.

[0043] Figure 3 It is a cross-sectional schematic diagram of the fingertip dynamic resistance mechanism.

[0044] Figure 4 Schematic diagram of the overall wearing of the variable resistance force feedback hand exoskeleton system.

[0045] Figure 5 This is a schematic diagram of the overall wearing and use of the variable resistance force feedback hand exoskeleton system.

[0046] Figure 6 This is a flow chart of the variable resistance force feedback hand exoskeleton control method provided by the present invention. DETAILED DESCRIPTION

[0047] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0050] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0052] Existing hand exoskeleton systems commonly suffer from uneven weight distribution due to complex structures. They often utilize rigid connecting rods and motor-driven structures, which restrict the freedom of finger movement. For example, during VR grasping operations, users often struggle with precise gestures due to interference from the exoskeleton with joint movement. Furthermore, insufficient force feedback accuracy leads to distorted tactile perception of virtual objects. Traditional devices improve feedback by increasing the number of drive components, but this increases the weight and size of the device, making it difficult to maintain for extended wear.

[0053] Example 1:

[0054] In order to solve the above problems, Figure 1-5 As shown, the present application proposes a variable resistance force feedback hand exoskeleton system, including a thumb base and multiple fingertip dynamic resistance mechanisms. The thumb base includes a thumb fixed support 9, a shaft fixed base 8 and a posture sensor. The fingertip dynamic resistance mechanism includes a shaft 6, a fingertip body 1, a finger fixing ring 4, a variable resistance assembly and a position sensor 5. The lower end of the shaft 6 is rotationally hinged to the shaft fixed base 8, and a limit block 7 is provided at the upper end. The fingertip body 1 is slidably set on the shaft 6, and the finger fixing ring 4 is used to fix the fingertip. The variable resistance assembly generates variable resistance by squeezing the shaft 6, and the position sensor 5 detects the relative position of the fingertip body 1.

[0055] The thumb support 9 is a rigid shell that encases the proximal phalanx of the thumb. It can be manufactured using an injection molding process, with its inner wall conforming to ergonomic curves. Its function is to ensure a stable thumb posture through rigid fixation and provide a reliable support point for the shaft 6. The shaft support base 8 is a metal connector integrally formed with the thumb support 9. This base eliminates backlash errors between moving parts through a rigid connection, ensuring the accuracy of the shaft 6's motion trajectory. The posture sensor is a miniature electronic component capable of detecting three-dimensional posture, specifically an IMU module integrating a gyroscope and accelerometer. It is directly mounted on the shaft support base 8 to capture real-time overall hand motion data. The shaft 6 is a smooth cylindrical guide rod, specifically made of stainless steel. Its rotary hinge design allows the fingertip mechanism to rotate with the palm, while a stopper 7 prevents the fingertip body 1 from slipping. The fingertip body 1 is a sliding component with a through-hole 23, the inner wall of which can be provided with a low-friction bushing. This design allows the finger to both slide along the shaft 6 and rotate freely, maintaining a natural motion state. The variable resistance component is a device that changes the resistance to movement through mechanical contact. Specifically, it can be an electromagnetic brake or pneumatic damper. Its force is applied perpendicular to the axis of the shaft 6, and linear resistance is achieved by adjusting the contact pressure. The position sensor 5 is a non-contact displacement detection device. Specifically, it can be an infrared ranging module, with the transmitter pointing toward the stop block 7 for distance measurement. This sensor converts physical displacement into an electrical signal, providing a data source for virtual environment mapping.

[0056] Specifically, the thumb base is rigidly connected to form a stable support structure, and each of the four finger mechanisms is independently mounted on a corresponding shaft 6. When a user performs a grasping motion, the fingers drive the fingertip body 1 to slide along the shaft 6, and the position sensor 5 records the distance moved in real time. When collision detection is triggered in the virtual environment, the controller sends a command to the variable resistance component, causing it to squeeze the shaft 6 to generate the corresponding resistance. The posture sensor simultaneously collects the hand's rotation angle, which, together with the displacement data, constitutes a complete motion parameter. The rotary articulation design of the shaft 6 allows for natural palm rotation, and the free rotation of the fingertip body 1 avoids constraints on the finger joints. This modular design separates the thumb from the four finger mechanisms, reducing mechanical linkage components while maintaining the independent movement of each finger. Through the above technical solutions, this application effectively reduces the overall weight of the exoskeleton system and makes the center of gravity distribution of the device more ergonomic. The independent movement of each finger avoids mechanical interference, enhancing the freedom of movement during virtual manipulation. Direct measurement of fingertip displacement combined with real-time resistance adjustment enhances the accuracy and responsiveness of force feedback. The modular design simplifies the assembly process, reducing manufacturing costs while improving device reliability.

[0057] In a specific implementation scheme, the position sensor 5 is a laser ranging sensor, the transmitting end of which is facing the limit block 7, and the relative position is calculated by measuring the distance between the sensor and the limit block 7. The laser ranging sensor refers to a measuring device that calculates the distance by using the time difference or phase difference between the emission and reception of the laser beam. Specifically, it can be implemented by a pulsed or phase-type laser sensor, and the displacement between the fingertip body 1 and the limit block 7 is obtained in a non-contact manner. The limit block 7 refers to a mechanical stop structure fixed to the top of the shaft 6. Specifically, it can be made of a reflective surface with a regular geometric shape made of metal or high-hardness plastic, which is used to provide a stable reflection reference for laser ranging and limit the maximum displacement range of the fingertip body 1. Specifically, the laser ranging sensor is mounted on the fingertip body 1, and its transmitting end is aligned with the limit block 7 at the top of the shaft 6 at a preset angle. When the fingertip body 1 slides along the shaft 6, the laser beam continuously illuminates the reflective surface of the limit block 7, and the sensor measures the change in the distance between the two in real time by receiving the reflected light signal. Because the limit block 7 is rigidly connected to the shaft fixing base 8 and its position remains fixed relative to the thumb base, the linear displacement of the fingertip body 1 along the shaft 6 can be directly converted into an increase or decrease in the laser ranging value. Through the above technical solution, this application achieves high-precision detection of the finger motion trajectory, ensuring that the exoskeleton system can accurately sense the linear displacement of the fingertip along the shaft 6. At the same time, the integrated design reduces the complexity of sensor installation and improves the long-term stability of the system.

[0058] In a specific embodiment, the attitude sensor is a multi-axis IMU attitude sensor, mounted on the shaft-mounted base 8. A multi-axis IMU attitude sensor is an integrated sensor capable of detecting acceleration, angular velocity, and magnetic field in three-dimensional space. Specifically, it can be implemented using a chip module containing a three-axis gyroscope, a three-axis accelerometer, and a three-axis magnetometer. It outputs attitude data such as pitch and roll angles through a fusion algorithm. The sensor is rigidly connected to the thumb base to maintain synchronized movement, avoiding measurement errors caused by independent installation. Specifically, the multi-axis IMU attitude sensor is directly embedded in the internal cavity of the shaft-mounted base 8, with its data acquisition direction aligned with the extension direction of the shaft 6. When the hand flexes, extends, or rotates, the sensor senses the spatial attitude changes of the thumb base in real time through the rigid connection to the shaft-mounted base 8 and transmits the raw data to a controller for Kalman filtering. Because the sensor and thumb base form an integrated structure, vibrations generated during hand movement are directly transmitted to the sensor housing through the rigid connection, avoiding signal delays or distortion caused by flexible installation. At the same time, the sensors are integrated within the shaft fixing base 8, eliminating the need for additional surface space on the exoskeleton, thereby preventing external brackets from interfering with the range of motion of the finger joints. Through the above technical solution, the present application can accurately capture the multi-dimensional posture changes during the overall movement of the hand, eliminate the measurement deviation caused by the independent installation of sensors, and reduce the spatial interference of the exoskeleton with the natural movement of the fingers, thereby improving the accuracy of hand posture mapping in the virtual environment and the user's wearing comfort.

[0059] like Figure 3 As shown, the fingertip body 1 is provided with a through hole 23 extending through the upper and lower end surfaces. The shaft 6 passes through the through hole 23, and the fingertip body 1 can be raised and lowered linearly along the shaft 6 and can freely rotate circumferentially. The through hole 23 extending through the upper and lower end surfaces refers to a cylindrical channel extending through the upper and lower surfaces of the fingertip body 1. Specifically, this can be achieved by using a hole formed by precision machining with an inner diameter slightly larger than the outer diameter of the shaft 6. This structure provides physical constraints for the fingertip body 1 to slide axially and rotate circumferentially. Circumferential free rotation refers to the fingertip body 1 being able to rotate 360 ​​degrees without restriction around the axis of the shaft 6. Specifically, this can be achieved by providing a layer of low-friction material between the inner wall of the through hole 23 and the surface of the shaft 6. This feature enables the finger to adaptively adjust the contact angle during the gripping process.

[0060] Specifically, the clearance between the through hole 23 and the shaft 6 forms a sliding substructure. When the finger flexes and extends, the fingertip body 1 moves linearly along the shaft 6 to simulate the displacement trajectory of the fingertip, and the position sensor 5 accurately measures the displacement by detecting the distance change of the limit block 7. When the finger twists laterally or fine-tunes the gripping posture, the fingertip body 1 rotates freely around the shaft 6 to eliminate the motion interference caused by the traditional rigid connection. The rotational freedom and the linear movement form a composite motion mode, which completely restores the three-dimensional motion characteristics of the finger joint. Through the above technical solution, the present application realizes the simulated motion trajectory of the finger's grasping action in a virtual environment. The composite freedom of axial movement and circumferential rotation compensates for the limitation of the traditional exoskeleton on lateral movement, so that the user does not need to resist the additional resistance generated by the device structure during operation, which significantly improves the flexibility and naturalness of the finger movement.

[0061] like Figure 1 and 2 As shown, the thumb support 9 is connected to a rigid fixing plate with an arc-shaped outer contour. A shaft fixing base 8 is mounted on the rigid fixing plate, and the shaft 6 fixed thereto is perpendicular to each fingertip. The rigid fixing plate with a curve-shaped outer contour refers to a support structure that adapts its morphology to the physiological curve of the palm in its natural state. Specifically, this can be achieved by using CNC machining or 3D scanning modeling to generate an arc-shaped surface that matches the palm's natural state. This structure reduces localized pressure concentration by adapting to human anatomical features. The shaft fixing base 8 is mounted on the rigid fixing plate, integrating the mounting base of the shaft 6 onto the surface of the arc-shaped fixing plate. This layout ensures that the mounting position of the shaft 6 is spatially aligned with the plane of finger motion. The shaft 6 being perpendicular to each fingertip means that the extension direction of the shaft 6 is orthogonal to the longitudinal axis of the finger when naturally extended. This can be achieved by adjusting the mounting angle of the shaft fixing base 8. This directional configuration ensures that the direction of resistance applied aligns with the trajectory of finger motion. Specifically, by designing the outer contour of the rigid fixing plate into an arc-shaped structure that fits the physiological curve of the palm in its natural state, the fixing plate can fit tightly to the thumb base area, improving the comfort of wearing and use. The shaft fixing base 8 is integrated into a specific position of the rigid fixing plate, so that the extension direction of the shaft 6 after installation forms a perpendicular relationship with the longitudinal axis of each fingertip. When the user performs a grasping action, the fingers move along a natural curved trajectory. At this time, the direction of the resistance generated by the shaft 6 forms an orthogonal effect with the direction of finger movement, thereby eliminating the joint movement interference caused by the deviation of the force feedback direction in traditional exoskeleton systems. This spatial layout optimizes the force transmission path, so that the direction of resistance application matches the biomechanical characteristics of the human body. At the same time, the fitting design of the arc-shaped fixing plate reduces the pressure of the device on the thumb area.

[0062] In a specific embodiment, a rigid stator passes through a first hole 20 in the thumb support 9 and is secured in place by a rubber ring. The thumb support 9 is provided with a second hole 22 for a thumb tie to pass through for length adjustment. The lateral hole refers to a through-hole structure provided on the side of the thumb support 9 and extending through its inner and outer walls. It can be fabricated by machining or injection molding, providing a path for the rigid stator and tie to pass through. The rubber ring, in particular, utilizes a rubber ring to radially constrain the rigid stator as it passes through the hole. This can be achieved by vulcanizing the rubber ring to the inner wall of the hole. The elastic deformation of the rubber compensates for assembly play and dampens vibration. The thumb tie is a flexible ribbon designed to secure the thumb. It can be made of nylon webbing or silicone. Its end can be adjusted in length using a Velcro or snap-on mechanism. Specifically, during assembly, the rigid stator passes through the first hole 20. The rubber ring wraps around the outer surface of the stator with an interference fit, maintaining the stator's axial position while allowing for minimal deformation, thereby avoiding stress concentration caused by rigid contact. The thumb tie passes through another set of second holes 22 and wraps around the user's thumb. Adjusting the length of the tie within the holes changes the circumferential size of the mounting bracket to accommodate varying thumb sizes. The inner walls of the holes guide the tie's sliding path, preventing it from shifting or twisting during adjustment.

[0063] like Figure 1 and 3As shown, the variable resistance assembly includes a variable resistance block 2 movably mounted on a fingertip body 1 adjacent to a shaft 6, and a driver 3 connected to the variable resistance block 2 via a transmission structure. The driver 3 drives the variable resistance block 2 toward or away from the shaft 6, generating a linearly varying resistance through compression. The variable resistance block 2 is a movable or rotatable component that contacts the shaft 6 and generates frictional resistance. Specifically, it can be implemented using a hinged or slider structure, with its contact surface covered with a flexible material to reduce sliding wear. The driver 3 is a power device that outputs linear or rotational motion. Specifically, it can be implemented using a micromotor or linear motor, achieving precise displacement control through transmission ratio adjustment. The transmission structure is a mechanical device that converts the output of the driver 3 into linear motion of the variable resistance block 2. Specifically, it can be implemented using a screw, rack and pinion, or connecting rod mechanism, amplifying the driving force and improving adjustment accuracy. Specifically, after receiving a control signal, the driver 3 propels the variable resistance block 2 along a predetermined trajectory through the transmission structure. When the variable resistance block 2 approaches the shaft 6, the contact pressure between it and the shaft 6 increases, generating a motion resistance proportional to the pressure through friction. The resistance changes linearly with the displacement of the variable resistance block 2, and the resistance can be continuously adjusted by adjusting the output of the driver 3. In the virtual object interaction scene, when it is detected that the finger contacts the virtual object, the control system generates a corresponding drive instruction based on the object hardness parameter, so that the variable resistance block 2 moves accurately to the target position, thereby generating real-time resistance feedback that matches the physical characteristics of the virtual object. Through the above technical solution, the present application can dynamically generate a linear resistance that matches the hardness of the object according to the virtual scene, and adjust the resistance gradient in real time during the bending of the finger, which not only ensures the low friction characteristics during free movement, but also provides accurate force feedback when contacting the object. The modular design of the variable resistance block 2 and the driver 3 simplifies the mechanical structure, so that the exoskeleton system has a high response speed while maintaining its lightweight, effectively solving the problems of adjustment hysteresis and lack of flexibility of traditional devices.

[0064] In a specific embodiment, the variable resistor block 2 is hinged to the fingertip body 1. Its side facing the shaft 6 has an outwardly convex curved surface covered with a flexible material. The driver 3 rotates the variable resistor block 2 about the hinge axis to adjust the distance from the shaft 6. The term "hinged" refers to the connection between the variable resistor block 2 and the fingertip body 1 via a rotating axis, enabling the variable resistor block 2 to rotate about a fixed axis. This can be achieved using a pin-and-bearing structure, which reduces the required degrees of freedom of movement required by the drive mechanism. The term "curved surface" refers to the continuously curved geometric shape of the contact surface of the variable resistor block 2, which can be achieved using a circular arc or parabolic profile. This shape gradually increases the contact area as it approaches the shaft 6. The term "flexible material" refers to the elastic material covering the contact surface of the variable resistor block 2, which can be implemented using silicone or rubber. This material absorbs impact energy and increases the coefficient of friction through deformation. Specifically, when the driver 3 rotates the variable resistor block 2 about the hinge axis, the curved surface gradually contacts the surface of the shaft 6. As the rotation angle increases, the contact area between the flexible material layer and the shaft 6 gradually expands, thereby generating a linearly increasing frictional resistance. The rotational motion avoids the common seizure in linear propulsion mechanisms and optimizes the force transfer path by converting tangential friction into normal pressure. The elastic deformation of the flexible material provides a buffer during initial contact, reducing vibrations from rigid collisions and maintaining a stable friction coefficient during continued extrusion.

[0065] This solution achieves a smooth transition in resistance change through the synergistic effect of rotational adjustment and flexible contact with the curved surface. The vibration noise and operational discomfort generated by rigid contact in existing technologies are absorbed by the flexible material layer and converted into controllable elastic deformation, significantly improving user comfort.

[0066] Furthermore, the variable resistance assembly also includes a slider 31 and a connecting rod 32 connecting the slider 31 and the variable resistance block 2. The driver 3 is a drive motor, whose output end is connected to a screw 33. The slider 31 is meshed and sleeved with the screw 33 to form a screw structure. The slider 31 refers to a mechanical component that meshes with the screw 33 and moves along the axis of the screw 33. Specifically, it can be implemented by a metal block with internal threads. The threaded engagement converts the rotational motion of the drive motor into linear displacement. The connecting rod 32 refers to a rigid connector with its ends hinged to the slider 31 and the variable resistance block 2, respectively. Specifically, it can be implemented by an aluminum alloy rod. It is used to transmit the linear thrust of the slider 31 to the variable resistance block 2 and convert it into a clamping action. The drive motor refers to an actuator that outputs rotational power. Specifically, it can be implemented by a stepper motor or a servo motor. The displacement of the slider 31 is precisely adjusted by controlling the motor's rotation angle. The screw 33 refers to a cylindrical transmission component with a threaded surface. Specifically, it can be implemented by turning stainless steel. It cooperates with the slider 31 to form a screw structure to achieve high-precision linear motion. Among them, the screw structure refers to a spiral transmission mechanism composed of a screw 33 and a slider 31, which can be specifically realized by a precision ball screw or a trapezoidal screw, and has a self-locking function to prevent position deviation caused by external interference. Specifically, when the drive motor is started, it drives the screw 33 to rotate, and the slider 31 moves along the axis of the screw 33 under the action of the thread engagement, pushing the variable resistance block 2 towards or away from the shaft 6 through the connecting rod 32. The linear displacement of the slider 31 is linearly related to the rotation angle of the drive motor, so that the degree of extrusion of the variable resistance block 2 on the shaft 6 can be precisely controlled. The self-locking characteristics of the screw structure can prevent the slider 31 from retreating due to external forces, ensuring the stability of the resistance adjustment. The leverage of the connecting rod 32 amplifies the linear thrust of the slider 31, so that even a small power motor can generate sufficient clamping force.

[0067] Example 2:

[0068] This application further proposes a variable resistance force feedback hand exoskeleton control method, which uses the variable resistance force feedback hand exoskeleton system described in Example 1 and includes the following steps:

[0069] (a) The distance between each fingertip and the thumb fixed support 9 is collected in real time by the position sensor 5;

[0070] (b) collecting the pitch angle and roll angle of the hand as a whole through the posture sensor 8;

[0071] (c) Controller execution:

[0072] -Map distance value to finger bending angle;

[0073] -Perform Kalman filtering on the attitude data to extract stable angle information;

[0074] (d) synchronizing the bend angle, pitch angle, and roll angle outputted in step (c) to the hand model in the virtual environment;

[0075] (e) generating a resistance control instruction when any fingertip enters the collision range of an object in the virtual environment; the collision range is a tolerance zone formed by a 2-5 mm offset in the normal direction of the object's mesh surface;

[0076] (f) The corresponding driver 3 is driven according to the resistance control instruction, pushing the variable resistance block 2 to squeeze the shaft 6 to generate a resistance that is positively correlated with the hardness of the virtual object.

[0077] The position sensor is a device used to detect the position of the fingertip relative to the shaft. Specifically, it can be implemented using a laser rangefinder. By measuring the distance to the stop block and calculating the relative position, this device directly acquires fingertip displacement data, avoiding the computational burden of traditional multi-joint angle calculations. The posture sensor is a device used to capture the overall spatial orientation of the hand. Specifically, it can be implemented using a multi-axis IMU posture sensor. It uses a Kalman filter algorithm to eliminate noise interference and ensure the stability of posture data. A Kalman filter is a signal processing algorithm that extracts valid angle information by recursively predicting and correcting the raw data output by the posture sensor. This algorithm can suppress the impact of environmental vibration or instantaneous jitter on data accuracy. The collision range is the detection area in the virtual environment that triggers resistance feedback. Specifically, this can be achieved by expanding the object mesh surface along the normal direction to create a tolerance zone, for example, offset by 2-5mm. This design avoids false triggers and improves collision detection sensitivity. The resistance control command is a drive signal generated based on the hardness of the virtual object. By adjusting the driver output power, the pressure of the variable resistance block on the shaft is varied, creating a linear relationship between the resistance and the object's hardness.

[0078] Specifically, the position sensor measures the dynamic distance between the fingertip and the thumb base in real time, and converts it into the finger bending angle through a linear mapping relationship. The pitch and roll angle data collected by the posture sensor are processed by the Kalman filter, which can effectively remove small hand tremors or instantaneous interference and ensure the motion continuity of the virtual hand model. The processed bending angle and posture data are synchronized to the virtual environment in real time, so that the physical action and the virtual model can be matched with low latency. When the virtual fingertip enters the fault tolerance area formed by the offset of the object mesh normal, the system generates a resistance control instruction based on the preset object hardness parameters. The driver pushes the variable resistance block to squeeze the shaft, generating resistance feedback that matches the physical characteristics of the virtual object.

[0079] This solution directly measures fingertip displacement using a position sensor and maps it to a bending angle, significantly simplifying the data processing process. Existing collision detection often uses fixed thresholds or simple geometric judgments, which can easily lead to false triggers or delayed responses. This solution constructs a dynamic tolerance zone based on the object's mesh normal direction, improving detection accuracy and reducing computational load. Traditional force feedback control relies on a preset fixed resistance curve, which cannot adapt to the physical characteristics of different virtual objects. This solution achieves dynamically adjustable resistance feedback by establishing a linear relationship between the hardness parameter and the actuator output. Through this technical solution, this application solves the device integration difficulties caused by complex data acquisition and computation. By directly collecting and mapping position and posture data, the controller's computational load is reduced, making it suitable for deployment on small embedded platforms. Kalman filtering and dynamic tolerance zone design improve data stability and collision detection accuracy, ensuring real-time and realistic virtual interactions. By linearly linking the hardness parameter with the actuator, the resistance feedback intensity is precisely matched to the characteristics of the virtual object, enhancing the consistency of the user's tactile perception when grasping objects of varying hardness.

[0080] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0081] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A variable resistance force feedback hand exoskeleton system, characterized in that: include: - Thumb base, containing: - a thumb fixing support (9) for fixing the thumb; - a plurality of shaft fixing bases (8) rigidly connected to the thumb fixing support (9); - Posture sensor, used to obtain the relative posture of the whole hand; - Multiple fingertip resistance mechanisms, each fingertip resistance mechanism comprising: - a shaft (6), the lower end of which is rotatably hinged to a corresponding shaft fixing base (8) on the thumb base, and a limit block (7) is provided at the upper end; - a fingertip body (1) slidably mounted on a shaft (6); - a finger fixing ring (4), fixed to the fingertip body (1), for fixing the tip of the index finger, middle finger, ring finger or little finger; - a variable resistance component, arranged on the fingertip body (1) and used for squeezing the shaft (6) to generate a variable resistance; - A position sensor (5), fixed on the fingertip body (1), for detecting the position of the fingertip body (1) relative to the shaft (6) in real time.

2. The variable resistance force feedback hand exoskeleton system according to claim 1, characterized in that: - The position sensor (5) is a laser distance measuring sensor, the emission end of which is directed toward the limit block (7), and the relative position is calculated by measuring the distance between the sensor and the limit block (7).

3. The variable resistance force feedback hand exoskeleton system according to claim 1, characterized in that: -The attitude sensor is a multi-axis IMU attitude sensor, which is arranged on the shaft fixed base (8).

4. The variable resistance force feedback hand exoskeleton system according to claim 1, characterized in that: - the fingertip body (1) is provided with a through hole (23) penetrating the upper and lower end surfaces, and the shaft (6) passes through the through hole (23); -The fingertip body (1) can be lifted and lowered linearly along the shaft (6) and can freely rotate in the circumferential direction.

5. The variable resistance force feedback hand exoskeleton system according to claim 1, characterized in that: - the thumb fixing support (9) is connected to a rigid fixing plate having an outer contour of a fitting curve, and the curve is in the shape of an arc; -The shaft fixing base (8) is arranged on the rigid fixing plate, and the shaft (6) fixed thereto is perpendicular to each fingertip.

6. The variable resistance force feedback hand exoskeleton system according to claim 5, characterized in that: - The rigid fixing plate passes through the first hole (20) of the thumb fixing support (9) and is fixed in place by a rubber ring; - The thumb fixing support (9) is provided with a second hole (22) for the thumb tie to pass through to adjust the length.

7. The variable resistance force feedback hand exoskeleton system according to claim 1, characterized in that: -The variable resistance component includes: - a variable resistance block (2), movably arranged on the fingertip body (1) next to the shaft (6); - a driver (3), connected to the variable resistance block (2) via a transmission structure; - The driver (3) drives the variable resistance block (2) to move closer to or away from the shaft (6), generating a linearly changing resistance by squeezing.

8. The variable resistance force feedback hand exoskeleton system according to claim 7, characterized in that: - the variable resistance block (2) is hinged to the fingertip body (1), and the side thereof facing the shaft (6) is an outwardly convex curved surface and is covered with a flexible material; - The driver (3) drives the variable resistance block (2) to rotate around the hinge axis to adjust the distance from the shaft (6).

9. The variable resistance force feedback hand exoskeleton system according to claim 7, characterized in that: - the variable resistance assembly further comprises a slider (31) and a connecting rod (32) connecting the slider and the variable resistance block (2); - The driver (3) is a driving motor, the output end of which is connected to the screw (33), and the slider (31) is engaged and sleeved on the screw (33) to form a screw structure.

10. A variable resistance force feedback hand exoskeleton control method, characterized in that Using the system according to any one of claims 1 to 9, performing: (a) collecting the distance value between each fingertip and the thumb fixed support (9) in real time through the position sensor (5); (b) Collecting the pitch and roll angles of the hand through the posture sensor; (c) Controller execution: -Map distance value to finger bending angle; -Perform Kalman filtering on the attitude data to extract stable angle information; (d) synchronizing the bend angle, pitch angle, and roll angle outputted in step (c) to the hand model in the virtual environment; (e) generating a resistance control instruction when any fingertip enters the collision range of an object in the virtual environment; the collision range is a tolerance zone formed by a 2-5 mm offset in the normal direction of the object's mesh surface; (f) driving the corresponding driver (3) according to the resistance control instruction, pushing the variable resistance block (2) to squeeze the shaft (6) to generate a resistance that is positively correlated with the hardness of the virtual object.

Images