Vision-enhanced force-position fusion measurement method and device based on double-link

Abstract

A visually enhanced force-position fusion measurement method and device based on a double-link mechanism relates to the field of robotic mechanical system design. To address the technical issues in the prior art, such as the high cost and complexity of existing dexterous hands, as well as the low measurement accuracy during force and position fusion measurement, the present invention provides a technical solution: a force-position fusion amplification measurement dexterous hand based on a link-slider combination, the dexterous hand comprising: a long, fixed guide rod at one end, two sliders that move radially along the guide rod; a tension spring, the two ends of the spring being connected to one end of the two guide rods; the other ends of the two guide rods being connected to two sliders; the tension spring performing a stretching motion along its own axis; and when the tension spring is pulled and performs a stretching motion, the two guide rods and the slider drive the guide rod to move around its fixed end. This method is suitable for application in the design of dexterous hands.

Description

Technical Field

[0001] The present invention relates to the field of mechanical system design of robots, and specifically to a design scheme and device for a dexterous hand that can efficiently measure force and position. Background Art

[0002] With the continuous advancement of robotics, higher demands are being placed on robots' ability to perform complex interactions with their environments. Dexterous hands, with their anthropomorphic, ultra-high degrees of freedom and dexterity, are poised to gradually replace traditional end-of-line grippers, playing a crucial role in aerospace, manufacturing, warehousing, smart healthcare, robotic services, and other fields. Dexterous hands, in order to achieve dexterous manipulation and control, rely on sensing their own force and position. Traditional solutions often involve installing angle encoders and torque sensors at each joint. However, dexterous hands typically possess numerous degrees of freedom, necessitating the purchase of an equal number of position and force sensors, which is costly. Furthermore, the installation and routing of these sensors requires additional mechanical design, increases power consumption, limits the size of the mechanism, and increases the complexity of the overall control system. Therefore, a new design and device for measuring the force and position of dexterous hands is urgently needed. While some researchers have proposed mechanisms for fused force and position measurement, these approaches suffer from low accuracy and large size. Summary of the Invention

[0003] To solve the technical problems existing in the prior art, such as the high cost and complexity of the existing dexterous hand and the low measurement accuracy in the work of force and position fusion measurement, the technical solution provided by the present invention is as follows:

[0004] A force-position fusion amplification measurement dexterous hand based on a connecting rod-slider combination, the dexterous hand comprising:

[0005] A long guide rod with one end fixed.

[0006] Two sliders moving radially along the guide rod;

[0007] A tension spring, wherein both ends of the spring are respectively connected to one end of the two guide rods;

[0008] The other ends of the two guide rods are connected to two sliders respectively;

[0009] The tension spring performs a stretching motion along its own axis;

[0010] When the tension spring is pulled and performs a stretching movement, the guide rod is driven to move around one of its fixed ends through the two guide rods and the slider.

[0011] Furthermore, a preferred embodiment is provided, which further includes a traction rope for traction of the tension spring.

[0012] Furthermore, a preferred embodiment is provided, which further includes a visual camera for observing the deformation and displacement of the tension spring.

[0013] Furthermore, a preferred embodiment is provided, which further includes two conductive shafts fixedly connected to the two ends of the tension spring respectively, for connecting the guide rod.

[0014] Furthermore, a preferred embodiment is provided, which further includes a motor for pulling the tension spring via a pulling rope.

[0015] A dual-link-based vision-enhanced force-position fusion measurement method, implemented based on the aforementioned dexterous hand, comprises:

[0016] The step of collecting spring deformation and displacement image data;

[0017] The step of obtaining joint torque and angle information of the dexterous hand according to the spring deformation and displacement image data;

[0018] The step of obtaining a control instruction according to the joint torque and angle information of the dexterous hand and sending the control instruction to the execution structure.

[0019] A vision-enhanced force-position fusion measurement device based on a double-link, which is implemented based on the aforementioned dexterous hand, comprises:

[0020] A module for collecting spring deformation and displacement image data;

[0021] A module for obtaining joint torque and angle information of the dexterous hand according to the spring deformation and displacement image data;

[0022] A control instruction is obtained according to the joint torque and angle information of the dexterous hand and sent to a module of an execution structure.

[0023] A computer storage medium is used to store a computer program. When the computer program is read by a computer, the computer executes the method.

[0024] A computer includes a processor and a storage medium. When the processor reads the computer program stored in the storage medium, the computer executes the method.

[0025] The computer program product, as a computer program, implements the method described above when the computer program is read.

[0026] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[0027] The force-position fusion amplification and measurement dexterous hand based on the connecting rod and slider combination provided by the present invention can observe the torque and angle information of all joints through the visual unit with only one monocular camera, saving the cost of purchasing and installing multiple force sensors and angle sensors.

[0028] The force-position fusion amplification and measurement dexterous hand based on the connecting rod and slider combination provided by the present invention solves the problems of multiple sensors and complex wiring, reduces the complexity of circuit design and power supply, and thus simplifies the overall structure.

[0029] The force-position fusion amplification measurement dexterous hand based on the connecting rod and slider combination provided by the present invention improves the accuracy of displacement and torque measurement through a visual unit and a data fusion algorithm, amplifies the displacement of the spring, and improves the minimum resolution.

[0030] The present invention provides a force-position fusion amplification measurement dexterous hand based on a connecting rod and slider combination. The design of the connecting rod and slider combination makes the measurement system more compact, reduces the space occupied by sensors and connecting wires, and thus reduces the volume of the overall mechanism.

[0031] The force-position fusion amplification and measurement dexterous hand based on the connecting rod and slider combination provided by the present invention reduces the number of sensors and complex circuit connections, thereby reducing the overall energy consumption of the system.

[0032] The force-position fusion amplification measurement dexterous hand based on a connecting rod-slider combination provided by the present invention realizes high-precision force and position information measurement in a compact system, significantly improving the performance and application prospects of the dexterous hand mechanism.

[0033] The force-position fusion amplification measurement dexterous hand based on a connecting rod-slider combination provided by the present invention is suitable for application in the design of dexterous hands. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the overall dexterous hand;

[0035] Figure 2 Schematic diagram of the force-position fusion measurement structure based on the connecting rod-slider combination;

[0036] Figure 3 for Figure 2 Schematic diagram of the guide rod and connecting rod structure;

[0037] Figure 4 Schematic diagram of the slider motion relationship when θ0 = 85°;

[0038] Figure 5 Schematic diagram of the slider motion relationship when θ0 = 80°;

[0039] Figure 6 Schematic diagram of the slider motion relationship when θ0=70°.

[0040] Among them, 1 represents the main structure of the dexterous hand, 2 represents the measurement unit, 3 represents the conduction axis, 4 represents the slider, 5 represents the spring, 6 represents the motor, 7 represents the traction rope, and 8 represents the camera. DETAILED DESCRIPTION

[0041] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0042] Embodiment 1: This embodiment provides a force-position fusion amplification measurement dexterous hand based on a connecting rod and slider combination 4, the dexterous hand comprising:

[0043] A long guide rod with one end fixed.

[0044] Two sliders 4 that move radially along the guide rod;

[0045] A tension spring 5, wherein both ends of the spring 5 are respectively connected to one end of the two guide rods;

[0046] The other ends of the two guide rods are respectively connected to two sliders 4;

[0047] The tension spring 5 performs a stretching motion along its own axis;

[0048] When the tension spring 5 is pulled and performs a stretching movement, the guide rod is driven to move around its fixed end through the two guide rods and the slider 4 .

[0049] Specifically:

[0050] include:

[0051] Motor 6

[0052] Function: Provide driving force to drive other components to move through the traction rope 7.

[0053] Connected to the tension spring 5, connected to the traction rope 7 through the winding drum.

[0054] Slider 4

[0055] Function: Sliding guide, achieving displacement amplification through the connecting rod mechanism.

[0056] Each group of two sliders 4 is located at both ends of the guide rod, connecting the tension spring 5 and the guide rod.

[0057] guide rod

[0058] Function: Provide a guide path for the slider 4.

[0059] The slider 4 slides along the guide rod.

[0060] Extension spring 5

[0061] Function: Measure the change of force and calculate the tension of the rope through the deformation.

[0062] One end is connected to the traction rope 7, and the other end is transmitted to the guide rod through the slider 4.

[0063] Traction rope 7

[0064] Function: Transmit force and displacement, connect motor 6 and tension spring 5.

[0065] One end is connected to the motor 6 and the other end is connected to the tension spring 5.

[0066] Vision Camera 8

[0067] Function: Observe the deformation and displacement changes of the tension spring 5.

[0068] Fixed in place, covering the entire field of view of the spring 5.

[0069] connecting rod mechanism

[0070] Function: Convert the axial displacement of the spring 5 into a lateral displacement under the field of view of the camera 8, and amplify the displacement.

[0071] Connects the slider 4 and the tension spring 5 to transmit force and displacement.

[0072] These components work together to achieve high-precision measurement and amplification of the force and displacement of the dexterous hand mechanism, and the torque and angle information of all joints can be observed through a monocular camera 8.

[0073] Implementation method 2: This implementation method further limits the force-position fusion amplification measurement dexterous hand based on the connecting rod slider 4 combination provided in implementation method 1, and further includes a traction rope 7 for pulling the tension spring 5.

[0074] Implementation method three: This implementation method further limits the force-position fusion amplification measurement dexterous hand based on the connecting rod slider 4 combination provided in implementation method one, and also includes a visual camera 8 for observing the deformation and displacement of the tension spring 5.

[0075] Implementation method 4: This implementation method further limits the force-position fusion amplification measurement dexterous hand based on the combination of the connecting rod and slider 4 provided in implementation method 1, and also includes two conduction shafts 3, which are respectively fixedly connected to the two ends of the tension spring 5 for connecting the guide rod.

[0076] Implementation method 5: This implementation method further limits the force-position fusion amplification measurement dexterous hand based on the connecting rod slider 4 combination provided in implementation method 1, and also includes a motor 6 for pulling the tension spring 5 through the traction rope 7.

[0077] Embodiment 6: This embodiment provides a dual-link vision-enhanced force-position fusion measurement method, which is implemented based on the dexterous hand provided in embodiment 1 and includes:

[0078] The step of collecting deformation and displacement image data of the spring 5;

[0079] The step of obtaining joint torque and angle information of the dexterous hand according to the deformation amount and displacement image data of the spring 5;

[0080] The step of obtaining a control instruction according to the joint torque and angle information of the dexterous hand and sending the control instruction to the execution structure.

[0081] The core technical problem to be solved in this implementation is the force and position sensing of a dexterous hand, particularly in terms of cost, space, and complexity. To this end, the document proposes a force-position fusion amplification measurement dexterous hand mechanism based on a connecting rod-slider combination. The software portion of the technical approach is divided into the following steps in chronological order:

[0082] Visual measurement preparation

[0083] Force and displacement data acquisition

[0084] Data processing and fusion

[0085] Output and Feedback

[0086] Detailed description

[0087] Visual measurement preparation

[0088] Output: Initial parameter settings and system calibration.

[0089] Step Description:

[0090] The initial position and focal length of the camera 8 are set to cover the field of view of all measuring springs 5 ​​.

[0091] The system is calibrated to ensure that the camera 8 can accurately identify the deformation and displacement of the spring 5.

[0092] Force and displacement data acquisition

[0093] Input: Image data captured by camera 8. Output: Deformation and displacement data of spring 5.

[0094] Step Description:

[0095] The camera 8 is used to capture the deformation image of the spring 5 in real time.

[0096] The deformation of the spring 5 is calculated by an image processing algorithm, and then the tension of the traction rope 7 is obtained.

[0097] The displacement of the top end of the spring 5 (the end connected to the tendon) relative to the initial moment is measured, and the joint rotation angle is obtained by conversion.

[0098] Data processing and fusion

[0099] Input: Deformation and displacement data of spring 5. Output: Joint torque and angle information of the dexterous hand.

[0100] Step Description:

[0101] The deformation of spring 5 is converted into joint torque information, and the torque value of each joint is obtained by calculation.

[0102] The displacement data of the top end of spring 5 is converted into the rotation angle information of the joint.

[0103] Using data fusion algorithms, data from multiple joints are comprehensively processed to improve overall measurement accuracy and stability.

[0104] Output and Feedback

[0105] Input: Joint torque and angle information of the dexterous hand. Output: Feedback signal of the control system.

[0106] Step Description:

[0107] Generate control instructions based on the processed joint torque and angle information.

[0108] Control instructions are sent to the actuators of the dexterous hand to adjust the movements of each joint.

[0109] Monitor the system status in real time and make necessary adjustments and optimizations to ensure stable operation of the dexterous hand.

[0110] These steps ensure that the dexterous hand mechanism can efficiently and accurately sense and control its own force and position in complex environments.

[0111] Embodiment 7: This embodiment provides a vision-enhanced force-position fusion measurement device based on a double-link. The device is implemented based on the dexterous hand provided in embodiment 1, and includes:

[0112] A module for collecting deformation and displacement image data of spring 5;

[0113] A module for obtaining joint torque and angle information of the dexterous hand according to the deformation and displacement image data of the spring 5;

[0114] A control instruction is obtained according to the joint torque and angle information of the dexterous hand and sent to a module of an execution structure.

[0115] Embodiment 8: This embodiment provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the method provided in embodiment 6.

[0116] Implementation method 9: This implementation method provides a computer, including a processor and a storage medium. When the processor reads the computer program stored in the storage medium, the computer executes the method provided in implementation method 6.

[0117] Embodiment 10: This embodiment provides a computer program product, which is a computer program. When the computer program is read, it implements the method provided in Embodiment 6.

[0118] Implementation Method 11: Combination Figure 1-6 This embodiment further describes the above technical solution in detail and completely through specific examples, specifically:

[0119] In order to solve the problems of dexterous hand force and position perception in traditional solutions, this embodiment has the problems of high cost of measurement unit 2, large space occupation, complex mechanism design, increased power consumption, reduced control stability, etc., and similar solutions proposed by existing researchers have not yet been applied in actual robot systems. Therefore, this embodiment mainly proposes a high-precision, compact five-finger dexterous hand system solution and device for force and position fusion measurement.

[0120] Figure 1 This is an overall schematic diagram of the dexterous hand, in which the dexterous hand main body structure 1 is connected to the measurement unit 2.

[0121] This embodiment proposes a new design for a tendon-driven dexterous hand system. First, a dexterous hand mechanism with 13 degrees of freedom is designed. Each joint is stretched by a tendon. A tension spring 5 is connected in series between the tendon and the motor 6. The deformation of all springs 5 ​​is transmitted through a linkage mechanism, converting the axial displacement of the spring 5 into a lateral displacement within the field of view of a camera 8, which can be observed by the camera 8. The deformation of the spring 5 is then measured visually to calculate the rope tension, which in turn provides the corresponding joint torque. Simultaneously, the displacement of the top of the spring 5 (the end connected to the tendon) relative to the initial moment can be measured visually, and the joint rotation angle can be obtained through conversion. By specially arranging the routing of all tendons, the visual unit's field of view can ultimately include all springs 5 ​​of the dexterous hand, thereby simultaneously measuring the torque and position information of all joints. This new dexterous hand design requires only a single monocular camera 8 to obtain torque and angle information for all joints of the dexterous hand, eliminating the need for angle sensors, torque sensors, and other devices on the 13 finger joints, saving mechanical costs and reducing the size of the mechanism.

[0122] The measuring device proposed in this embodiment is composed of a motor 6, a slider 4, a guide rod, a tension spring 5, a rope, and a visual camera 8. Each group of two sliders 4 is located at both ends of the guide rod. Figure 2 As shown, through this mechanism, the displacement is amplified.

[0123] The steps for deriving the relationship between the movement distances of each group of two sliders 4 are as follows:

[0124] Step 1: The end where the spring 5 is connected to the traction rope 7 is recorded as the tail end of the spring 5, and the end where the spring 5 is connected to the winding drum fixed with the traction rope 7 is recorded as the head end of the spring 5. Figure 2 As shown, the angle between the connecting rod and the guide rod is θ0 at the initial moment, and the angle is θ after moving a certain distance. At the same time, the length of the connecting shaft connecting the slider 4 connecting rod to the lower transverse connecting rod is L1, and the length of the connecting shaft connecting the slider 4 connecting rod to the lower transverse connecting rod is L2.

[0125] Step 2: Calculate the relationship between the displacement Δl1 of the slider 4 and the displacement Δy1 of the tail end of the spring 5, and the relationship between the displacement Δl2 of the slider 4 and the displacement Δy2 of the head end of the spring 5. The displacement Δl1 of the slider 4 reflects the displacement Δy1 of the tail end of the spring 5, and the displacement Δl2 of the slider 4 reflects the displacement Δy2 of the head end of the spring 5. It is easy to get:

[0126]

[0127] Step 3: Based on the formula obtained in step 2, after calculation, we can get the motion relationship between the two sliders 4 under different conditions of θ0 as follows: Figure 3-6 It is found that when the difference between θ and θ0 is within a certain range, the mechanism can always play the role of amplifying the displacement of the slider 4.

[0128] The steps for measuring joint torque (equivalent to providing the function of joint torque sensor) are as follows:

[0129] Step 1: A tension spring 5 is installed at one end of the traction rope 7. The elongation Δl of the tension spring 5 is observed visually (such as by a camera 8). The calculation formula is as follows:

[0130] Δl=Δy2-Δy1,

[0131] Step 2: The stiffness k of the tension spring 5 is a known quantity. Since the tension spring 5 is connected to the traction rope 7, the force F exerted on the tension spring 5 is k The pulling force F on the traction rope 7 l Equal, the calculation formula is as follows:

[0132] F=F=k ·Δl

[0133] Step 3: The traction rope 7 is subjected to a tension Fl When , the torque transmission wheel will be driven to rotate. The radius of the torque transmission wheel is known to be r, and the calculation formula of the rope-driven joint torque τ is:

[0134] τ=F l ·r,

[0135] The steps to measure joint angles (equivalent to providing the function of joint angle encoders) are as follows:

[0136] Step 1: The end of the spring 5 connected to the traction rope 7 is recorded as the tail end of the spring 5. At the initial time t0, the position y10 of the tail end of the spring 5 relative to the world coordinate system can be measured by a visual device (such as a camera 8);

[0137] Step 2: After the joint rotates by angle θ, at time t1, the position y of the end of the spring 5 relative to the world coordinate system can be measured by a visual device (such as camera 8). 11 ;

[0138] Step 3: Since the traction rope 7 (its length is fixed) is connected to the end of the spring 5, the distance the end of the spring 5 moves is the distance the traction rope 7 drives the torque transmission wheel to rotate. The distance the end of the spring 5 moves during the process of t0 to t1 is y 11 -y 10 ,, under the condition of ignoring the strain of the rope itself, the joint angle θ and y 11 -y 10 The relationship is:

[0139] y 11 -y 10 ,

[0140] Where r is the radius of the torque transmission wheel. The calculation formula of the joint angle can be obtained by transformation:

[0141]

[0142] The steps for measuring the rotation angle of motor 6 (equivalent to providing the function of a servo encoder) are as follows:

[0143] Step 1: The end of the spring 5 connected to the winding drum fixed traction rope 7 is recorded as the head end of the spring 5. At the initial time t0, the position y of the head end of the spring 5 relative to the world coordinate system can be measured by a visual device (such as a camera 8). 20 ;

[0144] Step 2: After the joint rotates by angle θ, at time t1, the position y of the head end of the spring 5 relative to the world coordinate system can be measured by a visual device (such as camera 8). 21 ;

[0145] Step 3: Since the winding drum is connected to the head end of spring 5 by a rope, ignoring the strain of the rope itself, the distance the head end of spring 5 moves is the angular displacement of the servo. The distance the head end of spring 5 moves during t0 to t1 is y 21 -y 20 , given that the radius of the winding drum is R, the rotation angle φ of the motor 6 can be deduced as:

[0146]

[0147] This embodiment utilizes a unique joint transmission and tendon arrangement design, combined with a specially designed connecting rod transmission relationship, to convert the axial displacement of the spring 5 into a lateral displacement within the field of view of the camera 8. Identifying the axial displacement of the spring 5 typically requires using a binocular camera 8 to extract depth information or a monocular camera 8 to directly detect the axial distance (expressed as a change in pixel size). Binocular cameras 8 are limited by size and lens spacing in mechanisms with strict size constraints (such as robotic arms). While monocular cameras 8 can detect changes in the deformation at both ends of the spring 5, the pixel coordinate changes caused by the axial distance within the field of view of the camera 8 are far smaller than the actual axial distance. More importantly, if the monocular camera 8 directly detects the axial displacement of the markings at the two ends of the spring 5, the markings at the two ends are often not in the same plane (they would obscure the markings behind them if they were in the same plane), making it difficult for the monocular camera 8 to obtain the actual deformation of the spring 5. Therefore, converting the axial displacement into lateral displacement through a connecting rod transmission effectively solves this problem. The measurement unit 2 (e.g., camera 8) can simultaneously detect the deformation of all tension springs 5, thereby calculating the torque and angle of each joint. This solution uses a single monocular camera 8 to replace the force and position information that can only be observed by multiple sets of force (or torque) and angle sensors. Therefore, it can solve the problems of high cost, complex circuit connections, increased power consumption, and increased control complexity of the measurement unit 2 in traditional solutions. Furthermore, compared to existing force and position measurement solutions in the prior art, this embodiment can amplify the displacement of the spring 5, thereby greatly improving measurement accuracy and reducing the size of the mechanism. Furthermore, a single camera 8 can be used to achieve all sensing functions.

[0148] The above further describes the technical solution provided by the present invention in detail through several specific embodiments in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific embodiments described above are not intended to limit the present invention. Any reasonable modification and improvement of the present invention, combination of embodiments and equivalent replacement based on the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A force-position fusion amplification measurement dexterous hand based on a connecting rod-slider combination, characterized by: The dexterous hand comprises: A long guide rod with one end fixed. Two sliders moving radially along the guide rod; A tension spring, wherein both ends of the spring are respectively connected to one end of the two connecting rods; The other ends of the two connecting rods are respectively connected to two sliders; The tension spring performs a stretching motion along its own axis; When the tension spring is pulled and performs a stretching movement, the two connecting rods and the slider drive the long strip guide rod to move around its fixed end; Also included is a traction rope for pulling the tension spring; Also included is a visual camera for observing the deformation and displacement of the extension spring; Convert the axial displacement of the spring deformation into a lateral displacement under the camera's field of view to amplify the displacement; The connecting slider and tension spring are used to transmit force and displacement, realizing high-precision measurement and amplification of the force and displacement of the dexterous hand mechanism. The visual camera observes the torque and angle information of all joints. The visual camera is a monocular camera.

2. The force-position fusion amplification measurement dexterous hand based on the connecting rod and slider combination according to claim 1 is characterized in that: It also includes two conduction shafts, which are fixedly connected to the two ends of the tension spring respectively and are used to connect the long strip guide rod.

3. The force-position fusion amplification measurement dexterous hand based on the connecting rod-slider combination according to claim 1 is characterized in that: The utility model further comprises a motor for pulling the extension spring via a pulling rope.

4. A visually enhanced force-position fusion measurement method based on a double-link, characterized in that: The method is implemented based on the dexterous hand according to claim 1, comprising: The step of collecting spring deformation and displacement image data; The step of obtaining joint torque and angle information of the dexterous hand according to the spring deformation and displacement image data; The step of obtaining a control instruction according to the joint torque and angle information of the dexterous hand and sending the control instruction to the execution structure.

5. A visually enhanced force-position fusion measurement device based on a double-link, characterized in that: The device is implemented based on the dexterous hand according to claim 1, and includes: A module for collecting spring deformation and displacement image data; A module for obtaining joint torque and angle information of the dexterous hand according to the spring deformation and displacement image data; A control instruction is obtained according to the joint torque and angle information of the dexterous hand and sent to a module of an execution structure.

6. A computer storage medium for storing a computer program, characterized in that When the computer program is read by a computer, the computer executes the method according to claim 4 .

7. A computer comprising a processor and a storage medium, characterized in that When the processor reads the computer program stored in the storage medium, the computer executes the method according to claim 4 .

8. A computer program product, being a computer program, characterized in that When the computer program is read, the method according to claim 4 is implemented.

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