Two-fingered manipulation hand based on elastic band self-adaptive wrapping and its grasping force estimation method

Abstract

This invention discloses a two-finger manipulator based on adaptive elastic band wrapping and its grasping force estimation method, belonging to the field of robot manipulator technology. It includes: a servo motor mounting frame, with a finger hinged to each of the left and right sides of the frame, and servos driving the fingers to rotate; two miniature reduction motors mounted on the servo motor mounting frame, each with a first gear fixed to its output shaft; two first shafts rotatably connected to the servo motor mounting frame, each with a second gear fixed to and meshing with the first gears; a pressure sensor fixed to each of the two fingers, one end of which is rotatably connected to a second shaft, and the upper ends of each finger rotatably connected to a third shaft; and an elastic band installed on each finger, the elastic band of each finger passing over the third shaft, the second shaft, and the first shaft closest to that finger, thus tensioning the elastic band and improving the flexible control of the grasped object.

Description

Technical Field

[0001] This invention belongs to the field of robot manipulator technology, specifically relating to a two-finger manipulator based on elastic band adaptive wrapping and its grasping force estimation method. Background Technology

[0002] Robotic manipulators are crucial components in industry. Existing robotic manipulators are typically made of rigid materials, which facilitates more precise control in grasping objects and allows for stable gripping of regularly shaped objects. However, due to material limitations, rigid manipulators have poor fit with the grasped object, making them unsuitable for grasping irregularly shaped or soft objects.

[0003] Soft robotic hands, benefiting from the low stiffness and deformability of soft materials, possess strong adaptability and high safety in interacting with the environment. Compared to rigid manipulators, soft robotic hands offer greater gripping stability for complex objects. Current soft robotic hand designs primarily focus on increasing envelope adaptability to objects of different geometries and sizes, but they struggle to simultaneously perform dexterous manipulatory tasks, such as controlling the translation of the grasped object along the horizontal X-axis and vertical Y-axis, as well as rotational motion around the Z-axis.

[0004] Chinese invention patent CN105773607B discloses a two-dimensional movable robot finger unit device, including a base finger segment, an end finger segment, a joint axis, a lateral movement component, and a longitudinal movement component. This device facilitates the picking up of flat objects from a table and uses the finger surface with two-dimensional motion to perform hand manipulation on the grasped object. However, due to its rigid structure and the size of the finger surface, the device cannot achieve compliant grasping of objects of different shapes and sizes.

[0005] Chinese invention patent CN113070896A discloses a soft manipulator based on a gecko toe, which includes a base and three bionic fingers. It can firmly grasp objects with complex shapes and soft objects, but the soft manipulator cannot further perform the task of manipulating the grasped object from within the hand, and its flexibility is poor. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a two-finger manipulator based on elastic band adaptive wrapping and its grasping force estimation method, thereby solving the problems in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The two-finger control hand based on the elastic band adaptive wrapping includes a servo bracket, with a finger hinged to each of the left and right sides of the servo bracket and a servo to drive the finger to rotate; the servo bracket is equipped with two micro geared motors, and a first gear is fixed to the output shaft of each motor; two first shafts are rotatably connected to the servo bracket, and a second gear is fixed to each of the two first shafts and meshes with the two first gears respectively.

[0009] A pressure sensor is fixed on each of the two fingers. One end of the pressure sensor is rotatably connected to a second shaft. The upper ends of the two fingers are rotatably connected to a third shaft. An elastic band is installed on each of the two fingers. The elastic band on each finger passes around the third shaft, the second shaft, and the first shaft near the finger, and the elastic band is stretched.

[0010] Furthermore, a fixed bracket is fixed on each of the front and rear sides of the servo motor mounting bracket, and two miniature geared motors are fixed on the two fixed brackets respectively.

[0011] Furthermore, a clearance groove is provided in the middle of the finger, and the pressure sensor is located in the clearance groove. One end of the pressure sensor is fixed to the finger, and the other end is rotatably connected to a second shaft.

[0012] Furthermore, bushings are fixedly fitted onto the first, second, and third shafts, and the bushings are in contact with the elastic band.

[0013] Furthermore, the third axis is rotatably connected to the finger via a bearing.

[0014] Furthermore, a flange is fixed at the base of the finger, and the output shaft of the servo motor is fixedly connected to the flange.

[0015] Furthermore, the flange is secured to the base of the finger using bolts.

[0016] Furthermore, the elastic band is made of silicone or rubber.

[0017] The above-mentioned method for estimating the grasping force of an adaptive two-finger manipulator based on an elastic band wrapping, where the object to be grasped is a cylindrical object, includes the following steps:

[0018] S1, Calculate the connection length Connection length Length of the contact portion between the elastic band and each bushing This allows for the calculation of the initial length of the elastic band before it contacts the cylindrical object being gripped. At this point, the initial tension of the elastic band measured by the pressure sensor is recorded as... ;

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] In the formula, They represent the lines respectively The length of the point These represent the center points of the second axis and the first axis, respectively. They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction; Indicates a connection The length of the point Indicates the center point of the third axis; express Connecting and The angle between the lines; They represent Connecting and The angle between the lines, Connecting and The angle between the lines; Indicates the radius of the bushings for shafts number one, two, and three;

[0026] S2, the pressure is obtained based on the relationship between the tension and pressure of the elastic band. The resultant force vector is obtained. Magnitude of the resultant force And calculate the tensile force vector at the upper contact point between the elastic band and the pressure sensor. ,count and The resultant force vector ,size This allows for the calculation of the pulling force when the operator is gripping the cylindrical object. Combined with grasping force Relationship:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035] In the formula, This indicates the tension force exerted on the elastic band at the left contact point with the third axis; R represents the radius of the bottom surface of the cylindrical object being gripped. , They represent points respectively , , A definite angle, , , These represent the upper and lower boundary points of the elastic band and the cylindrical object being gripped, as well as the point on the horizontal line; They represent arrive shaft and Distance between axes; This indicates the tensile force at the upper contact point between the elastic band and the pressure sensor; Indicates tension The angle with the horizontal direction; Indicates the measurement of tensile force The tension at the lower contact point between the elastic band and the pressure sensor The included angle;

[0036] S3, using the initial length obtained from S1 Calculate the actual gripping force when in the vertical gripping state. size:

[0037]

[0038]

[0039]

[0040]

[0041] In the formula, This refers to the increase in length when the elastic band moves to the vertical clamping position. This is the total length of the elastic band when it is in the vertical clamping position. The added tension to the elastic band The elastic coefficient of the elastic band;

[0042] S4, Calculate the actual grasping force when the object is manipulated and moved within the fingers. size:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051] In the formula, This refers to the length of the elastic band when an object is grasped and manipulated within the fingers. To obtain the connection using S1 Length, To obtain the connection using S1 Length, The arc length is obtained for S1; They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction; These represent the states when the object is grasped and manipulated within the fingers. Connecting and Angle between the lines Connecting and Angle between the lines Connecting and The angle of the connecting line; This refers to the increased tension of the elastic band when grasping an object and manipulating it within the fingers, compared to the vertical gripping state.

[0052] A robot comprising the aforementioned two-finger manipulator based on an elastic band adaptive wrapping.

[0053] The beneficial effects of this invention are:

[0054] 1. The two-finger manipulator of this invention utilizes the flexibility and elasticity of the wrapping band itself. When gripping a target object, the robot can control the opening and closing of its fingers to grasp the object, and then use a motor to drive the elastic band to rotate, thereby achieving the process of gradually engulfing the object from contact until it is effectively wrapped. This manipulator has strong grasping flexibility and can fully wrap objects of various complex shapes within the range of the fingers, thus producing a reliable grip.

[0055] 2. The two-finger manipulator of the present invention can flexibly adjust the magnitude of the gripping force applied to the object by controlling the degree of opening and closing of the fingers; through the measuring device, the magnitude of the force applied to the object can be measured, and the magnitude of the gripping force required to grasp the object can be calculated through kinematic and static analysis, providing feedback for the gripping force control of flexible and fragile objects.

[0056] 3. The two-finger manipulator of this invention can drive the rotation of an elastic band through the rotation of a micro-reduction motor. The rotation of the elastic band allows the manipulator to move the object being grasped from the fingertips inwards. The rotation of the elastic band can also cause the object to rotate. Furthermore, in conjunction with the swinging of the fingers, it achieves three degrees of freedom control over the grasped object: two translational movements and one rotational movement within the hand. This enables the manipulator to flexibly control the grasped object. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the operator's hand according to the present invention;

[0059] Figure 2 This is a side view of the overall structure of the operator's hand according to the present invention;

[0060] Figure 3 This is a cross-sectional view of the third axis system of the fingertips of the operator's hand in this invention;

[0061] Figure 4 This is a schematic diagram illustrating the calculation of the elastic band circumference in the initial state of the operator's hand before grasping an object, according to the present invention.

[0062] Figure 5 This is a static analysis diagram of the kinematics calculation of the operator's gripping state when grasping a cylindrical object according to the present invention;

[0063] Figure 6 This is a schematic diagram illustrating the calculation of the elastic band circumference when the operator of the present invention is in a translating state while grasping a cylindrical object;

[0064] Figure 7 This is a schematic diagram of the operator's fingertips contacting the bottom of the cylindrical object before grasping it;

[0065] Figure 8 This is a schematic diagram showing the fingers of the operator hand of the present invention spread out when grasping a cylindrical object;

[0066] Figure 9 This is a schematic diagram showing the fingers closing when the operator of the present invention grasps a cylindrical object;

[0067] Figure 10 This is a schematic diagram of the operator of the present invention fully grasping the cylindrical clamping object;

[0068] Figure 11 This is a schematic diagram of the operator hand of the present invention moving to the left while holding the cylindrical object;

[0069] Figure 12 This is a schematic diagram of the operator holding a square object in the present invention.

[0070] Figure 13 This is a schematic diagram of the operator holding the square object and rotating it counterclockwise by 15°.

[0071] Figure 14 This is a schematic diagram of the operator's hand gripping a square object and rotating it counterclockwise by 45°.

[0072] Figure 15 This is a schematic diagram of the operator's hand gripping a square object and rotating it counterclockwise by 80°.

[0073] Figure 16 This is a schematic diagram of the operator gripping a star-shaped, non-convex polyhedral object according to the present invention;

[0074] Figure 17 This is a schematic diagram of the operator holding a star-shaped non-convex polyhedral geometric shape and translating it to the right.

[0075] Figure 18 This is a schematic diagram of the operator grasping and manipulating the object using the sphere according to the present invention.

[0076] In the diagram: 1-Servo motor; 2-Servo motor mounting bracket; 3-Mounted bracket; 4-Miniature geared motor; 5-First gear; 6-Second gear; 7-First shaft; 8-Pressure sensor; 9-Finger; 10-Second shaft; 11-Elastic band; 12-Third shaft; 13-Flange; 14-Busset; 15-Bearing; 16-Cylindrical gripper; 17-Square gripper; 18-Star gripper; 19-Spherical gripper. Detailed Implementation

[0077] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0078] Example 1

[0079] like Figure 1 and Figure 2 As shown, the two-finger control hand based on the adaptive wrapping of the elastic band includes a servo bracket 2, with a finger 9 hinged to each of the left and right sides of the servo bracket 2, and a servo motor 1 fixedly installed on each of the left and right sides of the servo bracket 2. The two servo motors 1 drive the two fingers 9 to rotate around their base, thereby realizing the opening and closing of the fingers.

[0080] The servo mount 2 has a fixed bracket 3 on its front and rear sides respectively. A micro gear motor 4 is fixed on each of the two fixed brackets 3. A first gear 5 is fixed on the output shaft of each of the two micro gear motors 4. Two first shafts 7 are rotatably connected to the servo mount 2. A second gear 6 is fixed on each of the two first shafts 7. The two second gears 6 mesh with the two first gears 5 respectively. The micro gear motor 4 transmits power to the first shafts 7 through the first gears 5 and the second gears 6, thereby realizing the rotation operation of the elastic belt.

[0081] A clearance groove is provided in the middle of each of the two fingers 9. A pressure sensor 8 is installed in each of the two clearance grooves. One end of the pressure sensor 8 is rotatably connected to a second shaft 10, and the other end is fixed to the finger 9. A third shaft 12 is rotatably connected to the upper end of each of the two fingers 9.

[0082] Two elastic bands 11 are installed on each of the two fingers 9. The elastic bands 11 on each finger 9 pass around the third axis 12, the second axis 10 and the first axis 7 near the finger, and can tighten the elastic bands 11. When the elastic bands 11 wrap around an object, the elastic bands 11 are squeezed by the object, which in turn generates tension at the second axis 10. The tension of the elastic bands 11 can be measured by the pressure sensor 8, and the pressure on the object can be calculated.

[0083] In this embodiment, as Figure 3As shown, the third shaft 12 is rotatably connected to the finger 9 through the bearing 15. A bushing 14 is fixed on the third shaft 12, and the elastic band 11 contacts the bushing 14. Similarly, bushings are also fixed on the first shaft 7 and the second shaft 10 to contact the elastic band 11. By means of the friction between the bushing and the surface of the elastic band 11, it can be ensured that the bushing does not slip with the elastic band 11 when rotating.

[0084] In this embodiment, a flange 13 is fixed to the base of the finger 9, and the output shaft of the servo motor 1 is fixedly connected to the flange 13, so that the servo motor 1 can provide power for the opening and closing of the finger 9. In addition, the flange 13 is fixed to the base of the finger 9 by bolts, which ensures that the finger 9 provides reliable support when performing hand operations on the grasped object, and at the same time facilitates the disassembly and installation of the finger 9.

[0085] It is worth mentioning that in this embodiment, the elastic band 11 is made of silicone with a high tensile breaking rate. Of course, in some embodiments, the elastic band 11 can also be made of elastic materials such as rubber with a high tensile breaking rate.

[0086] Example 2

[0087] like Figures 4 to 6 As shown, in this embodiment, for the object to be grasped as a cylindrical gripper 16, a method for estimating the gripping force of the operating hand in Embodiment 1 is proposed, which specifically includes the following steps:

[0088] S1, the initial length of the elastic band 11 when it is not in contact with the cylindrical clamp 16 is calculated using kinematics:

[0089] S11, use the Law of Cosines to obtain the connecting line. length :

[0090] (1)

[0091] In equation (1), They represent the lines respectively The length of the point These represent the center points of axis 10 (second axis) and axis 7 (first axis), respectively. They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction;

[0092] S12, using equation (1) and the law of cosines, we obtain the connecting line. length :

[0093] (2)

[0094] In equation (2), Indicates a connection The length of the point Indicates the center point of axis 12 (number 3); express Connecting and The angle between the lines;

[0095] S13, the length of the contact portion between the elastic band 11 and each bushing is obtained using the arc length formula. :

[0096] (3)

[0097] (4)

[0098] (5)

[0099] In equations (3), (4), and (5), These represent the center point of axis 10 (second axis) and the center point of axis 7 (first axis), respectively. They represent Connecting and The angle between the lines, Connecting and The angle between the lines; Indicates the radius of the bushings for shafts number one, two, and three;

[0100] S14, calculate the total length of the elastic band 11 in its initial state before it grabs any objects. :

[0101] (6)

[0102] S15, record the initial tension of the elastic band measured by the pressure sensor at this time as... ;

[0103] S2, Calculation Figure 5 The operator of the present invention measures the pulling force when gripping the cylindrical object 16. Combined with grasping force Relationship:

[0104] S21, the pressure is obtained based on the relationship between the tension and pressure of the elastic band 11. :

[0105] (7)

[0106] In equation (7), R represents the tensile force exerted on the elastic band 11 at the left contact point with the third shaft 12; R represents the radius of the bottom surface of the cylindrical clamping object 16.

[0107] S22, by integrating the pressure, the force caused by the pressure of the elastic band 11 can be calculated. arrive Total force The resultant force vector is obtained. :

[0108] (8)

[0109] In equation (8), , They represent points respectively , , A definite angle, , , These represent the upper and lower boundary points of the elastic band 11 and the cylindrical clamping object 16, as well as the point on the horizontal line, respectively.

[0110] S23, the resultant force vector is obtained using equation (8). Size :

[0111] (9)

[0112] S24, Calculate the tensile force vector at the upper contact point between the elastic band 11 and the pressure sensor 8. :

[0113] (10)

[0114] In equation (10), They represent arrive shaft and Distance between axes; This indicates the tensile force at the upper contact point between the elastic band 11 and the pressure sensor 8; Indicates tension The angle with the horizontal direction;

[0115] S25, utilizing and If they are equal in size, calculate and The resultant force vector :

[0116] (11)

[0117] S26, obtained using equation (11) and The combined force size:

[0118] (12)

[0119] S27, using force measurement The horizontal component is The relationship between the two can be obtained as follows:

[0120] (13)

[0121] In equation (13), Indicates the measurement of tensile force The tension at the lower contact point between the elastic band 11 and the pressure sensor 8 The included angle;

[0122] S28, utilizing tension and Given that the sizes are equal and equations (9) and (13) are also equal, we get:

[0123] (14)

[0124] Recorded as:

[0125] (15)

[0126] S3, using the initial elastic band length 11 obtained from S1, calculate Figure 5 Actual gripping force in the vertical gripping state shown size:

[0127] S31, calculate the increase in length of elastic band 11 compared to equation (6) at this time. :

[0128] (16)

[0129] S32, Calculation Figure 5 The total length of the elastic band 11 in the vertical clamping state shown :

[0130] (17)

[0131] S33, treating the elastic band 11 as a linear spring, calculate the increased tension. :

[0132] (18)

[0133] In equation (18), The elastic modulus of elastic band 11;

[0134] S34, using equations (15), (18) and S15, we obtain Figure 5 Actual gripping force in the vertical gripping state shown :

[0135] (19)

[0136] S4, Calculation Figure 6 The figure shows the actual grasping force when the object is manipulated and moved within the fingers. size:

[0137] S41, Calculation Figure 6 The length of the elastic band 11 :

[0138] S411, using S11 to obtain the connection. length :

[0139] (20)

[0140] In equation (20), They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction;

[0141] S412, using S12 to obtain the connection. length :

[0142] (twenty one)

[0143] S413, using S13 to obtain the length :

[0144] (twenty two)

[0145] (twenty three)

[0146] (twenty four)

[0147] In equations (22), (23), and (24), They represent Figure 6 hour Connecting and The angle between the lines, Connecting and The angle between the lines, Connecting and The angle of the connecting line;

[0148] S414, Calculation Figure 6 The total length of the elastic band 11 :

[0149] (25)

[0150] S42, calculate the elastic band 11 relative to ( Figure 5 (The) vertical clamping state, move to the right to control (such as) Figure 6 Increased tension during () :

[0151] (26)

[0152] S43, Calculation Figure 6 Actual gripping force :

[0153] Using equations (15) and (26), we obtain Figure 6 Actual gripping force :

[0154] (27).

[0155] Working principle:

[0156] The in-hand control movement mode of the operator as described in Example 1:

[0157] This invention introduces the working principle of the grasping operation of the device, combined with... Figures 7 to 10 The description is as follows:

[0158] The operator's initial position is as follows: Figure 7 As shown, the two servo motors 1 control the fingers 9 to open. When the fingertips of the fingers 9 touch the sides of the cylindrical gripper 16, the two micro geared motors 4 start simultaneously, driving the corresponding first shaft 7 to rotate. This causes the two elastic bands 11 to move along the fingertips, which in turn causes the contact surfaces of the elastic bands 11 and the cylindrical gripper 16 to rotate simultaneously towards the fingertips. Under the action of the friction of the elastic bands 11, the cylindrical gripper 16 moves inward towards the fingers. Figure 8 As shown. Finally, it completely enters the interior of finger 9, as... Figure 9 As shown. The elastic band 11 wraps around the cylindrical gripper 16 to achieve the gripping operation, as shown. Figure 10 As shown.

[0159] The working principle of the translation operation of the invention device, combined with Figure 10 and Figure 11 The description is as follows:

[0160] The operator's initial position is as follows: Figure 10 As shown, after the cylindrical gripper 16 is wrapped by the two elastic bands 11, the two servo motors 1 control the fingers 9 to move counterclockwise simultaneously. At this time, the elastic bands 11 drive the cylindrical gripper 16 to move to the left in the XY plane, realizing the translation operation, as shown. Figure 11 As shown. During the movement, the elastic band 11 always wraps around the cylindrical object 16.

[0161] The working principle of the in-hand rotation operation of the device of the present invention, combined with Figures 12 to 15 The object to be gripped is a square object 17, described as follows:

[0162] The operator's initial position is as follows: Figure 12 As shown, the square gripper 17 undergoes the aforementioned grasping motion. The servo motor 1 adjusts the position of the finger 9, ensuring that the elastic band 11 provides a suitable gripping force on the square gripper 17, allowing for rotational friction. Two miniature geared motors 4 drive the corresponding first shaft 7 to rotate, causing one elastic band 11 to rotate along the fingertip direction while the other rotates in the opposite direction. At this time, the two elastic bands 11 provide frictional forces in opposite directions to the square gripper 17. This causes the square gripper 17 to rotate around the Z-axis, thereby achieving rotations of 15°, 40°, and 80° within the hand, as shown below. Figure 13 , Figure 14 and Figure 15 As shown. When the square gripper 17 reaches the target position, the micro reduction motor 4 stops, realizing the rotation operation inside the hand. During the operation, the elastic band 11 can still stably grip the square gripper 17.

[0163] like Figure 16 and Figure 17 The initial position of the operator is as follows: Figure 16 As shown, at this time, the operator performs a grasping operation to grasp the star-shaped gripper 18. Relying on the active surface of its elastic band 11, it can adapt to the complex surface shape of the star-shaped gripper 18 and form a stable envelope while completing the rightward translational movement, as shown. Figure 17 As shown, this demonstrates the operator's excellent adaptability.

[0164] like Figure 18 At this time, the operator performs a grasping operation to grasp the ball and hold the object 19. Relying on the active surface of its elastic band 11, it can adapt to the surface shape of the ball and hold the object 19, and still form a stable envelope when completing the translational movement, which demonstrates the good adaptability of the operator.

[0165] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions 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 one or more embodiments or examples.

[0166] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for estimating the grasping force of a two-fingered adaptive wrapping hand based on an elastic band, the grasped object being a cylindrical grasped object (16), characterized in that, The two-finger control hand includes a servo mount (2), with a finger (9) hinged to each of the left and right sides of the servo mount (2), and a servo (1) is set to drive the finger (9) to rotate; two micro geared motors (4) are set on the servo mount (2), and a first gear (5) is fixed on the output shaft of each motor; two first shafts (7) are rotatably connected to the servo mount (2), and a second gear (6) is fixed on each of the two first shafts (7) and meshes with the two first gears (5); A pressure sensor (8) is fixed on each of the two fingers (9). One end of the pressure sensor (8) is rotatably connected to a second shaft (10). The upper ends of the two fingers (9) are rotatably connected to a third shaft (12). An elastic band (11) is installed on each of the two fingers (9). The elastic band (11) on each finger (9) passes around the third shaft (12), the second shaft (10), and the first shaft (7) near the finger (9), and tensions the elastic band (11). A bushing is fixedly fitted on the first shaft (7), the second shaft (10) and the third shaft (12), and the bushing is in contact with the elastic band (11); The gripping force estimation method includes the following steps: S1, the length of the connecting line , the length of the connecting line , the length of the contact part of the elastic band (11) and the shaft sleeve , so as to calculate the initial length of the elastic band (11) when it does not contact the cylindrical clamped object (16) At this time, the initial tension of the elastic band measured by the pressure sensor is recorded as ;​​ （1） （2） （3） （4） （5） （6） In the formula, They represent the lines respectively The length of the point These represent the center points of the second axis (10) and the first axis (7), respectively. They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction; Indicates a connection The length of the point Indicates the center point of the third axis (12); express Connecting and The angle between the lines; They represent Connecting and The angle between the lines, Connecting and The angle between the lines; Indicates the radius of the bushings for shafts number one, two, and three; S2, the pressure is obtained based on the relationship between the tension and pressure of the elastic band (11). The resultant force vector is obtained. Magnitude of the resultant force And calculate the tensile force vector at the upper contact point between the elastic band (11) and the pressure sensor (8). ,count and The resultant force vector ,size Thus, the tension is measured when the operator is in the state of grasping the cylindrical object (16). Combined with grasping force Relationship: （7） （8） （9） （10） （11） （12） （13） （14） In the formula, R represents the tension force on the elastic band (11) at the left contact point with the third shaft (12); R represents the radius of the bottom surface of the cylindrical clamp (16); , They represent points respectively , , A definite angle, , , These represent the upper and lower boundary points of the elastic band (11) and the cylindrical clamping object (16), as well as the points on the horizontal line, respectively. They represent arrive shaft and Distance between axes; This indicates the tension at the upper contact point between the elastic band (11) and the pressure sensor (8); Indicates tension The angle with the horizontal direction; Indicates the measurement of tensile force The tension at the lower contact point between the elastic band (11) and the pressure sensor (8) The included angle; S3, using the initial length obtained from S1 Calculate the actual gripping force when in the vertical gripping state. size: （16） （17） （18） （19） In the formula, The increase in length when the elastic band (11) moves to the vertical clamping state. The total length of the elastic band (11) in the vertical clamping state. The added tension to the elastic band (11), is the elastic coefficient of the elastic band (11); S4, Calculate the actual grasping force when the object is manipulated and moved within the fingers. size: （20） （21） （22） （23） （24） （25） （26） （27） In the formula, The length of the elastic band (11) when the object is grasped and manipulated within the fingers is being moved. To obtain the connection using S1 Length, To obtain the connection using S1 Length, The arc length is obtained for S1; They represent the lines respectively The angle between the horizontal direction and the line connecting them The angle between the horizontal direction and the horizontal direction; These represent the states when the object is grasped and manipulated within the fingers. Connecting and Angle between the lines Connecting and Angle between the lines Connecting and The angle of the connecting line; The elastic band (11) provides increased tension when grasping an object in a manipulative state within the fingers, compared to the vertical gripping state.

2. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 1, characterized in that, A fixed bracket (3) is fixed on the front and rear sides of the servo mounting bracket (2), and two micro geared motors (4) are fixed on the two fixed brackets (3) respectively.

3. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 1, characterized in that, A relief groove is provided in the middle of the finger (9), and the pressure sensor (8) is located in the relief groove. One end of the pressure sensor (8) is fixed to the finger (9), and the other end is rotatably connected to the second shaft (10).

4. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 1, characterized in that, The third shaft (12) is rotatably connected to the finger (9) via a bearing (15).

5. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 1, characterized in that, A flange (13) is fixed at the base of the finger (9), and the output shaft of the servo motor (1) is fixedly connected to the flange (13).

6. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 5, characterized in that, The flange (13) is fixed to the base of the finger (9) by bolts.

7. The grasping force estimation method for a two-finger manipulator based on adaptive elastic band wrapping according to claim 1, characterized in that, The elastic band (11) is made of silicone or rubber.

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