Flexible gripper based on conductive liquid self-sensing detection

Abstract

The invention relates to the field of mechanical gripper analysis, in particular to a flexible gripper based on conductive liquid self-sensing detection, which comprises a stepping motor, a transmission connecting piece connected with the stepping motor, and at least one pair of flexible fingers connected with the transmission connecting piece, the flexible finger further comprises a plurality of conductive liquid sensors which are installed on the longest non-grabbing working surface in the flexible finger in the mode of being arranged in the length direction, and the bending state of the flexible finger is obtained by detecting the output condition of each conductive liquid sensor. The conductive liquid sensors are embedded into the flexible fingers, the conductive liquid sensors and the flexible gripper are combined into a whole, the conductive liquid sensors can be better matched with the gripper to work during gripping, a gripped object cannot be damaged, and the durability of the gripper is improved; and in addition, the bending state of the fingers of the gripper can be detected in real time, morphological structure parameters of the gripped object are obtained, detection of the gripped object is more accurate, the gripping efficiency is improved, and then the productivity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical gripper analysis, and in particular to a flexible gripper based on self-sensing detection of conductive liquid. Background Art

[0002] Traditionally, objects are grasped by rigid grippers, which have the advantages of accurate grasping, good strength, rigidity and reliability. However, the disadvantage is that they are not flexible enough and are usually used to grasp objects with regular shapes. They have poor adaptability to the grasped objects. At present, the sensors used in flexible grippers are attached to the surface of the grippers. The sensors are easy to slip off, causing damage to the clamped objects, and may impose certain restrictions on the movement of the grippers, and cannot accurately reflect the grasping situation of the grippers in real time. In recent years, due to the huge potential of the use of soft materials in grippers, they can be applied to a variety of complex scenarios. Therefore, the design and manufacture of soft grippers have attracted widespread attention from researchers at home and abroad. Compared with rigid materials, soft materials are more flexible and have better adaptability to materials of different shapes. In addition, soft materials have smaller mass, better safety and better human-computer interaction. Flexible grippers can grasp fragile and complex-shaped objects such as fruits, toys, eggs, and medical equipment. Compared with rigid grippers, they have stronger adaptability and flexibility.

[0003] At present, the research on the driving mode and material preparation of the gripper has achieved certain results, but the research on the perception detection of flexible grippers is still relatively small. The flexible bending sensors for detecting bending are mostly attached to the surface of the gripper. This method may lead to insufficient accuracy due to poor adhesion, and cannot accurately predict the bending state of the gripper in real time, and cannot further process the perception information. In the detection of some fragile items, the items may be damaged, and this problem needs to be solved now. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a flexible gripper based on self-sensing detection of conductive liquid.

[0005] A flexible gripper based on self-sensing detection of conductive liquids, comprising a stepper motor, a transmission connection connected to the stepper motor, at least one pair of flexible fingers connected to the transmission connection, and also comprising a plurality of conductive liquid sensors installed along the length direction on the longest non-grasping working surface of the flexible fingers. The bending state of the flexible fingers is obtained by detecting the output of each conductive liquid sensor.

[0006] The beneficial effects of the present invention are as follows: the flexible fingers of the present invention are embedded with a conductive liquid sensor, and the conductive liquid sensor is integrated with the flexible gripper, which can better cooperate with the gripper when grasping, will not cause damage to the grasped object, and increases the durability of the gripper; in addition, the bending state of the fingers of the gripper can be detected in real time, the morphological structure parameters of the grasped object can be obtained, the detection of the grasped object is more accurate, the grasping efficiency is improved, and thus the productivity is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0008] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0009] Figure 2 A schematic diagram of a flexible finger of the present invention;

[0010] Figure 3 It is a schematic diagram of the bending of the gripper of the present invention;

[0011] Figure 4 It is a schematic diagram of the conductive liquid sensor of the present invention;

[0012] Figure numerals: 1. flexible finger; 2. conductive liquid sensor; 3. connecting side panel; 4. sensor cover; 5. motor base; 6. stepper motor; 7. connecting plate; 8. connecting rod; 9. circular connector. DETAILED DESCRIPTION

[0013] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below.

[0014] like Figures 1 to 4 As shown, a flexible gripper based on self-sensing detection of conductive liquid includes a motor base 5, a stepper motor 6 arranged on the motor base 5 as a power source, a transmission connector connected to the stepper motor 6, and at least one pair of flexible fingers 1 connected to the transmission connector. The motor base 5 is connected to an external robot arm by bolts, and also includes a plurality of conductive liquid sensors 2 installed on the longest non-grasping working surface of the flexible finger 1 in an arranged manner along the length direction. By detecting the output of each conductive liquid sensor 2, the bending state of the flexible finger 1 is obtained, and the morphological structure parameters of the grasped object are obtained in real time.

[0015] It is explained here that the side of the flexible finger 1 in the present invention that is used to clamp and contact the grasped object is defined as a grasping working surface, and the side that does not contact the grasped object is defined as a non-grasping working surface, wherein, Figure 1As shown, several conductive liquid sensors 2 are distributed on the longest non-grasping working surface of the flexible finger 1 or the end surface opposite to the grasping working surface of the flexible finger 1, and are arranged along the length direction of the flexible finger 1. In this way, the conductive liquid sensors 2 are basically distributed along the length direction of the flexible finger 1. By monitoring the output of each section of the conductive liquid sensor 2, the posture of each part of the flexible finger 1 can be known, and finally the bending state of the entire flexible finger 1 can be fitted, for example Figure 3 The detection is a form shown, and this detection can reflect the posture of the flexible finger 1 in real time, which is beneficial to the precise control of the flexible finger 1, such as precise control of the opening angle.

[0016] The present invention utilizes the forward and reverse rotation of the stepping motor 6 to transmit power by means of a transmission connection to drive the flexible finger 1 to move, thereby realizing the switching of the opening and closing actions of the flexible gripper.

[0017] As an embodiment of a transmission connection member of the present invention, the transmission connection member specifically includes a connection side plate 3 respectively arranged on each flexible finger 1, a connection plate 7 hinged to the connection side plate 3 and installed on the stepper motor 6, a connection rod 8 respectively hinged to the corresponding connection side plate 3, and a circular connection member 9 arranged between the connection rods 8 and hingedly connected to the connection rods 8, and the stepper motor 6 drives the circular connection member 9 to move up and down. The stepper motor 6 of the present invention is directly connected to the circular connection member 9 by a threaded connection, that is, when the output shaft of the stepper motor 6 rotates, the two sides of the circular connection member 9 are restricted by the connection rod 8 and cannot rotate with the output shaft, so that the circular connection member 9 only moves up and down relative to the stepper motor 6, and with the help of the linkage of the connection rod 8, the connection side plates 3 are rotated around their respective hinge points with the connection plates 7 to synchronously drive the corresponding flexible fingers 1 to swing.

[0018] Specifically, the transmission connecting parts of the present invention are all in the shape of a plate and are made of iron, so the manufacturing cost is low and they are more suitable for long-term use.

[0019] Specifically, the flexible finger 1 is made of silicone material, and the contact area is in line-surface coordination, which is not likely to cause deformation to other workpieces when in use.

[0020] The flexible finger 1 is in the shape of a triangle, hollowed out in the middle, and connected by a crossbeam. When the flexible finger 1 is subjected to force, the main deformation occurs at the front contact point and the rear point of the crossbeam, and the overall structure can be greatly deformed, but the crossbeam can remain relatively unchanged, so that it can adapt to the shapes of different objects and can well adapt to the shape of the object to achieve grasping.

[0021] The conductive liquid sensor 2 is a flexible bending sensor. The present invention obtains the bending condition of the gripper through the output of each section, obtains the deformation of the gripper, and adjusts the force of the gripper. After a number of conductive liquid sensors 2 are connected together, the whole is connected in a multi-section strip shape. When each section is bent, the resistance value of the section changes. The resistance value corresponds to the bending angle. By measuring the resistance value of the section, the deformation of the gripper in the section can be obtained.

[0022] A set of data for a specific application implementation is as follows:

[0023]

[0024] like Figure 4 As shown, the conductive liquid sensor 2 is a sandwich structure, including PDMS 21 arranged on both upper and lower layers, a conductive liquid 22 filled in the middle position, and a wire 23 connected to the end of the PDMS 21 and electrically connected to the outside world. The Chinese name of the PDMS material is polydimethylsiloxane.

[0025] Grooves arranged along the length direction are provided on the longest non-grasping working surface of the flexible finger 1 , and the conductive liquid sensor 2 is embedded in the grooves of the flexible finger 1 .

[0026] like Figure 1 As shown, in order to achieve protection of the conductive liquid sensor 2, the present invention has been optimized and improved, and the flexible finger 1 is connected with a sensor cover 4 for encapsulating the conductive liquid sensor 2. Of course, in order to adapt to the shape adjustment of the flexible finger 1, the sensor cover 4 of the present invention can also be made of flexible materials, such as silicone materials.

[0027] In practical applications, the stepper motor 6 may be a lead screw stepper motor, or other components that achieve equivalent or similar working performance, such as a cylinder, etc. The present invention can be powered by an external power supply connected to the stepper motor 6, and has a good driving stability effect.

[0028] As a further optimized design, the connecting plate 7 is configured as a large C-shape to facilitate connection with other components in the present invention. Of course, it can also be made into other shapes according to actual application scenarios.

[0029] As a further optimized design, the circular connecting member 9 is in the shape of a segmented cylinder.

[0030] As a further optimized design, the connecting side plate 3 is provided with a plurality of groups of weight-reducing holes for reducing weight. The weight-reducing holes are increased or decreased according to actual needs. The weight-reducing holes of the present invention are not limited to cylindrical shapes, but can also be other shapes.

[0031] As an embodiment of the present invention, Figure 1As shown, the flexible fingers 1 are a pair. When in use, the output shaft of the stepper motor 6 starts to rotate forward / reverse through an external power supply, driving the circular connecting member 9 to move up / down, and the up / down movement of the circular connecting member 9 drives the connecting rod 8 to swing, so as to drive the connecting side plate 3 to rotate around the hinge point with the connecting plate 7, thereby driving the flexible fingers 1 to swing, and the pair of flexible fingers 1 can form an opening and closing effect.

[0032] Of course, the number of the flexible fingers 1 of the present invention can also be optimized and adjusted according to the actual occasion or the shape and structure of the grasped object, and such adjustment should fall within the protection scope of the present invention.

[0033] The above shows and describes 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 above embodiments and descriptions only describe the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A flexible gripper based on self-sensing detection of conductive liquid, characterized in that: The invention comprises a stepping motor (6), a transmission connection connected to the stepping motor (6), at least one pair of flexible fingers (1) connected to the transmission connection, and also comprises a plurality of conductive liquid sensors (2) installed on the longest non-grasping working surface of the flexible fingers (1) in an arranged manner along the length direction, and the bending state of the flexible fingers (1) is obtained by detecting the output of each conductive liquid sensor (2).

2. According to claim 1, a flexible gripper based on conductive liquid self-sensing detection is characterized in that: The transmission connecting member comprises a connecting side plate (3) respectively arranged on each flexible finger (1), a connecting plate (7) hinged to the connecting side plate (3), a connecting rod (8) respectively hinged to the corresponding connecting side plate (3), and a circular connecting member (9) arranged between the connecting rods (8) and connected to the connecting rods (8) by a hinged connection. The stepping motor (6) drives the circular connecting member (9) to move up and down.

3. According to claim 1, a flexible gripper based on conductive liquid self-sensing detection is characterized in that: The flexible finger (1) is made of silicone material.

4. The flexible gripper based on conductive liquid self-sensing detection according to claim 1, characterized in that: The flexible finger (1) is in the shape of a triangle, is hollowed out in the middle, and is connected by a crossbeam.

5. The flexible gripper based on conductive liquid self-sensing detection according to claim 1 is characterized in that: The conductive liquid sensor (2) is a flexible bending sensor, and a plurality of conductive liquid sensors (2) are connected to form a multi-segment long strip shape.

6. The flexible gripper based on conductive liquid self-sensing detection according to claim 1, characterized in that: The conductive liquid sensor (2) is a sandwich structure, comprising PDMS (21) arranged on both upper and lower layers, a conductive liquid (22) filled in the middle, and a wire (23) connected to the end of the PDMS (21) and electrically connected to the outside.

7. The flexible gripper based on conductive liquid self-sensing detection according to claim 1 is characterized in that: A groove arranged along the length direction is provided on the longest non-grasping working surface of the flexible finger (1), and the conductive liquid sensor (2) is embedded in the groove of the flexible finger (1).

8. The flexible gripper based on conductive liquid self-sensing detection according to claim 1, characterized in that: The flexible finger (1) is connected to a sensor cover plate (4) for encapsulating a conductive liquid sensor (2).

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