End effector and robot based on multi-sensor fusion of bi-stable state

Abstract

A bi-stable multi-sensor fusion end effector and robot includes a pair of sensing grippers, a grasping force control device, a bi-stable control device, and a depth sensing element. The sensing grippers include a sensing membrane and a pressure sensor. The bi-stable control device is coupled to the sensing grippers via an elastic mechanism, and the grasping force control device is coupled to the sensing membrane. The bi-stable control device initially overcomes the elastic force to open the pair of sensing grippers. When the depth sensing element senses that a target object has entered the grasping range, the elastic force is released to close the pair of sensing grippers. Based on the pressure state on the sensing membrane surface sensed by the pressure sensor, the grasping force control device controls the sensing membrane to retract before a successful grasp to achieve non-destructive grasping of the target object. Upon successful grasping, the sensing membrane is released to apply pressure to the target object. This invention offers significant advantages in grasping speed, grasping stability and non-destructiveness, intelligent sensing, and overall miniaturization.

Description

Technical Field

[0001] The present invention relates to a robot grasping technology, and in particular to an end effector and a robot based on bi-stable multi-sensor fusion. Background Art

[0002] In recent years, with the development of robotics and related technologies, gripping devices have been increasingly applied in industries such as agriculture, services, and biomedicine, leading to a surge in their design and research. However, current gripping devices are primarily divided into rigid and flexible grippers, and most employ fully active control designs. These designs fail to achieve ultra-fast grasping, resulting in a low success rate for grasping high-speed objects. Furthermore, existing gripping devices primarily focus on grasping performance, with relatively little research on the perception of the object after grasping.

[0003] In China, a team from Zhejiang University designed a flexible, fast-closing three-finger grasping device modeled on the principles of the Venus flytrap, and a bi-stable device using rubber bands and air pressure differentials. A team from Dalian University of Technology designed a flexible, two-finger grasping device modeled on the human hand skeleton using tension springs and rubber bands. A team from Beijing Institute of Technology designed a fast grasping device for use in space using flexible materials and rope-driven reset. Overseas, FM Naser et al. designed a bi-stable, ultra-fast aerial grasping and adaptive manipulator using the potential energy of torsion springs. These research results can all quickly grasp target objects, but they lack the ability to actively control the grasping force during rapid grasping, failing to effectively ensure the integrity of the grasped object. Furthermore, none of these research projects have a post-grasp object perception system, making it impossible to confirm the various physical properties of the grasped object in an unknown environment, and thus unable to further determine the object's type.

[0004] At IROS-2019, FM Naser et al. proposed a passively closed, adaptive manipulator design capable of ultra-fast mid-air grasping of a wide variety of everyday items. They also investigated alternative uses of structural compliance in developing simple, adaptive robotic grippers and hands, and proposed an appropriate quick-release mechanism to facilitate instantaneous grasping. The quick-release mechanism is triggered by a simple distance sensor. The manipulator utilizes only two actuators to control multiple degrees of freedom across three fingers, maintaining the superior grasping capability of the adaptive grasping mechanism even in uncertainties regarding the object's posture or other environmental factors. The manipulator achieves a grasping time of 96 milliseconds, a maximum grasping force of 56 Newtons, and is capable of securing objects of various shapes at high speeds. The manipulator can serve as an end effector for grasping drone platforms, providing hovering capabilities and facilitating autonomous docking.

[0005] In 2021, a team from Zhejiang University proposed a three-finger soft gripper for the challenges of high-speed dynamic grasping tasks. This gripper, called a high-speed soft gripper (HSG), is based on two basic design concepts. One is the rapid passage through instability, which enables the HSG to sense mechanical stimuli and actuate immediately. The other is a spider-inspired pneumatic control system that makes the triggering process repeatable and controllable. Using a pressure response strategy, the HSG can achieve high-speed perception and grasping, and handle dynamic grasping tasks such as catching a thrown baseball.

[0006] A team from Beijing Institute of Technology designed a rapid grasping device for use in space using flexible materials and rope-driven reset. The device uses purely flexible materials, and the grasping force depends on the recovery characteristics of the flexible material. The grasping force is small and is only suitable for grasping in space.

[0007] The shortcomings of the prior art mainly include:

[0008] 1. It fails to ensure the non-destructiveness of the grasped object, that is, the grasping force cannot be controlled, and most of them are only suitable for grasping objects with strong rigidity.

[0009] 2. Most of the existing fast grasping end effectors are designed with purely mechanical structures, only pursuing fast grasping, and fail to set up perception systems before, during and after grasping, and are insufficiently intelligent.

[0010] 3. Most fast grasping end effectors are designed to grasp a relatively simple object and are unable to adapt to objects of various shapes.

[0011] 4. The design scheme for applying the bi-stable characteristics to the fast grasping end effector is relatively simple.

[0012] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0013] The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide an end effector and a robot based on bi-stable multi-sensor fusion.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] A bi-stable multi-sensor fusion end effector comprises a pair of sensing gripper devices, a grasping force control device, a bi-stable control device and a depth sensing element. The sensing gripper device comprises a sensing membrane and a pressure sensor. The bi-stable control device is coupled to the sensing gripper device via an elastic mechanism. The grasping force control device is coupled to the sensing membrane. The bi-stable control device initially overcomes the elastic force to open the pair of sensing gripper devices, and releases the elastic force to close the pair of sensing gripper devices when the depth sensing element senses that the target object enters the grasping range. The grasping force control device controls the sensing membrane to retract inward to non-destructively grasp the target object before successful grasping based on the pressure state of the sensing membrane surface sensed by the pressure sensor, and releases the sensing membrane to apply pressure to the target object when the grasping is successful.

[0016] Further:

[0017] The sensing clamping device further includes a first force control plate, a second force control plate, a first force control linear plate, a second force control linear plate, a first ball guide rail, a second roller guide rail and a clamping base; the first ball guide rail is mounted on the front side of the interior of the clamping base, the second ball guide rail is mounted on the rear side of the interior of the clamping base, the first force control plate and the second force control plate are coaxially connected by a rotating pin, and the rotating pin is connected to the moving blocks on the first roller guide rail and the second roller guide rail; one side of the first force control linear plate and the second force control linear plate is connected to the first force control plate and the second force control linear plate The two force control plates are coaxially connected by a rotating pin, and the other side is connected to the upper side and the lower side of the inner part of the clamping jaw base in a linearly movable manner, and the whole is installed on the empty plane of the clamping jaw base; the sensing membrane is installed on the upper side of the first pressure sensor and the second pressure sensor, and coincides with the rectangle formed by the first force control plate and the second force control plate; the movement of the first ball guide and the second roller guide adjusts the degree of retraction of the sensing membrane; the first force control plate and the second force control plate are connected to the edge of the clamping jaw base by an elastic member; preferably, the elastic member is an elastic belt.

[0018] The pressure sensor includes a first pressure sensor and a second pressure sensor. The first pressure sensor is installed on the outside of the first force control plate, and the second pressure sensor is installed on the outside of the second force control plate. The sensing membrane is installed on the upper side of the first pressure sensor and the second pressure sensor.

[0019] The sensing gripper device further includes a visual shape sensing module, which projects pattern light onto the sensing film pressed on the target object and takes a picture to sense the shape of the target object.

[0020] The visual shape perception module includes an endoscopic camera, a red LED light strip, a green LED light strip, and a blue LED light strip; the red LED light strip, the green LED light strip, and the blue LED light strip are installed on the front, upper, and lower slopes inside the clamp base; preferably, it also includes a flat soft mirror film installed on the inner side of the clamp base, and the endoscopic camera is installed on the inner rear side of the clamp base, with a viewing angle sideways looking at the soft mirror film.

[0021] The two grasping force control devices are respectively arranged on the outer back of the two sensing jaws, and the grasping force control devices include a brushless servo motor, a flange connector, a first winding block, a second winding block, a first steel wire rope and a second steel wire rope; the brushless servo motor is directly installed on the outer back of the sensing jaw; the flange connector is installed on the upper side of the brushless servo motor; the first winding block and the second winding block are installed on the outer sides of the two side surfaces of the flange connector; one end of the first steel wire rope is connected to the first winding block and the flange connector, and the other end is connected to the first ball guide rail through the back channel of the sensing jaw; one end of the second steel wire rope is connected to the second winding block and the flange connector, and the other end is connected to the second ball guide rail through the back channel of the sensing jaw. The brushless servo motor is driven to rotate to control the outward pulling amount of the steel wire rope, so that the ball guide rail moves backward to realize the force control operation during grasping.

[0022] The bi-stable control device is arranged at the rear end of the sensing clamping device, and the bi-stable control device includes a cylinder, a first linear guide rail, a second linear guide rail, an electromagnet, a first tension spring, a second tension spring, a first connecting rod, a second connecting rod, a moving block, a magnetic patch, a first variable damping hinge, a second variable damping hinge, a first steering block, a second steering block, a pad and a base;

[0023] The first linear guide and the second linear guide are installed in parallel on the upper side of the bottom plate inside the base, the moving block is installed on the upper side of the first linear guide and the second linear guide slider, and the magnetic patch is installed on the rear side of the moving block, facing the rear end of the base; the cylinder is installed on the front end plate inside the base, the telescopic rod is extended and retracted in the direction of the telescopic rod toward the rear end of the base, and is arranged at the front end of the moving block; the electromagnet is installed on the rear end plate inside the base, facing the magnetic patch; the first variable damping hinge and the second variable damping hinge are installed on the front end surface outside the base and are installed symmetrically on the left and right; the first steering block is connected to the movable end of the first variable damping hinge, the long end of the first connecting rod and the first steering block are coaxially connected by a rotating pin, and the short end and the moving block are coaxially connected by a rotating pin; the second steering block is connected to the movable end of the second variable damping hinge, the long end of the second connecting rod and the second steering block are coaxially connected by a rotating pin, and the short end and the moving block are coaxially connected by a rotating pin; the first tension spring is installed between the tension spring fixings on the upper sides of the two sensing jaws, and the second tension spring is installed between the tension spring fixings on the lower sides of the two sensing jaws.

[0024] The depth sensing element includes a depth camera and a laser ranging sensor; the depth camera is installed at the upper end of the housing of the bi-stable control device; the laser ranging sensor is arranged at the front end of the bi-stable control device, and a gap is formed between the pair of sensing gripper devices to provide a field of view for the laser ranging sensor; preferably, the sensing gripper device includes a photoelectric switch installed at the front end, which is used to determine the timing when the target object enters the grasping range and trigger the laser ranging sensor to work.

[0025] A method for grasping an object using the end effector.

[0026] A robot comprises the above-mentioned end effector.

[0027] The present invention has the following beneficial effects:

[0028] The present invention overcomes the shortcomings of existing grasping end effectors and provides an end effector based on bi-stable multi-sensor fusion. The end effector can grasp moving objects non-destructively and quickly, and perceive the texture, shape, quality and other characteristics of the object after completing the grasp.

[0029] The end effector of the present invention is equipped with a sensing gripper device, a grasping force control device, a bi-stable control device, a shell and a depth sensing element, which can realize fast and non-destructive grasping of high-speed moving objects. After grasping, it can perceive the characteristics of the grasped object through multi-sensor fusion, thereby realizing intelligent grasping of high-speed moving unknown objects.

[0030] Compared with traditional technologies, the end effector of the embodiment of the present invention has significant advantages in terms of grasping speed, grasping stability and non-destructiveness, intelligent perception, and overall miniaturization. Specifically:

[0031] 1. The end effector of the embodiment of the present invention is designed with a sensing gripper device, a grasping force control device, a bi-stable control device, a housing and a depth sensing element. It can combine with the grasping prediction algorithm to perform ultra-fast and non-destructive grasping of high-speed moving objects in the air and perform perception of the grasped objects. The overall design is automated and highly intelligent.

[0032] 2. In the end effector of the embodiment of the present invention, a bi-stable control device is composed of a tension spring, a cylinder, and an electromagnet, which has the characteristics of rapid action and stable maintenance of the bi-stable state. In addition, the tension springs of different wire diameters can be easily replaced according to needs, and the clamping speed of the sensing clamp can be quickly adjusted, and it has good quick-change characteristics.

[0033] 3. In the end effector of the embodiment of the present invention, a grasping force control device is provided on the basis of the sensing gripper device, so that the force exerted by the gripper on the target object can be adjusted in time when the bi-stable characteristic is used for rapid grasping, thereby ensuring the target object is grasped without damage and the quality of the grasping.

[0034] 4. In the end effector of the embodiment of the present invention, the principle of mirror reflection is combined with the design of the visual tactile sensor modeled after a trampoline. Compared with the design of traditional visual tactile sensors, the possibility of damage to the grasped object is reduced and the miniaturization of the end effector is improved.

[0035] 5. The end effector of the embodiment of the present invention combines multiple sensing devices such as depth cameras, laser ranging sensors, pressure sensors, photoelectric switches, and visual and tactile sensors to form a multi-sensor fusion perception system, which improves the level of intelligence before, during, and after grasping.

[0036] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the overall structure of the end effector according to an embodiment of the present invention.

[0038] Figure 2A Schematic diagram of the overall structure of the sensing gripper device according to an embodiment of the present invention.

[0039] Figure 2B Schematic diagram of the concave state of the two force control plates of the sensing clamping device according to an embodiment of the present invention.

[0040] Figure 2C Schematic diagram of the back of the two force control plates of the sensing gripper device according to an embodiment of the present invention.

[0041] Figure 3 Schematic diagram of the internal structure of the sensing gripper device according to an embodiment of the present invention Figure 1 .

[0042] Figure 4 This is a second schematic diagram of the internal structure of the sensing gripper device according to an embodiment of the present invention.

[0043] Figure 5 Schematic diagram of the structure of a gripping force control device according to an embodiment of the present invention.

[0044] Figure 6 Schematic diagram of the structure of a bi-stable control device according to an embodiment of the present invention.

[0045] Figure 7 Schematic diagram of the structure of the housing of an embodiment of the present invention.

[0046] Figure 8 FIG. 4 is a schematic structural diagram of a depth sensing element according to an embodiment of the present invention.

[0047] Figure 9 4 is a flowchart of an embodiment of the present invention.

[0048] Among them, 1-sensing gripper device, 2-grasping force control device, 3-two-stable control device, 4-housing, 5-depth sensing element, 6-gripper base, 7-linear bearing, 8-first force control linear plate, 9-first force control plate, 10-sensing film, 11-photoelectric switch, 12-first roller guide, 13-TPU belt, 14-second force control plate, 15-second force control linear plate, 16-first pressure sensor, 17-second roller guide, 18-second pressure sensor, 19-tension spring support, 20-endoscopic camera, 21-soft mirror film, 22-red LED light strip, 23-green LED light strip, 24 -Blue LED light strip, 25-Brushless servo motor, 26-Flange connector, 27-Wire rope, 28-Winding block, 29-Second winding block, 30-Second wire rope, 31-First damping hinge, 32-First steering block, 33-Cylinder, 34-Second steering block, 35-Second damping hinge, 36-Second connecting rod, 37-Moving block, 38-Linear guide, 39-Electromagnet, 40-Base, 41-Magnetic patch, 42-First connecting rod, 43-First tension spring, 44-Second tension spring, 45-Upper housing, 46-Spacer, 47-Lower housing, 48-Depth camera, 49-Laser ranging sensor. DETAILED DESCRIPTION

[0049] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0050] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0051] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0052] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0053] See Figures 1 to 9 An embodiment of the present invention provides an end effector based on bi-stable multi-sensor fusion, comprising a pair of sensing gripper devices 1, a grasping force control device 2, a bi-stable control device 3 and a depth sensing element 5, wherein the sensing gripper device 1 comprises a sensing film 10 and a pressure sensor (such as 16, 18), the bi-stable control device 3 is coupled to the sensing gripper device 1 through an elastic mechanism, and the grasping force control device 2 is coupled to the sensing film 10, the bi-stable control device 3 initially overcomes the elastic force to open the pair of sensing gripper devices 1, and releases the elastic force to close the pair of sensing gripper devices 1 when the depth sensing element 5 senses that the target object enters the grasping range, realizing bi-stable operation of opening and closing through elastic energy storage characteristics, and quickly switching between two stable states, the grasping force control device 2 controls the sensing film 10 to retract before the grasping is successful to perform non-destructive grasping of the target object according to the pressure state of the surface of the sensing film 10 sensed by the pressure sensor, and releases the sensing film 10 to apply pressure to the target object when the grasping is successful.

[0054] An embodiment of the present invention further provides a robot, comprising the end effector.

[0055] An embodiment of the present invention also provides a method for grasping an object using the end effector.

[0056] The end effector of the embodiment of the present invention can utilize the characteristics of bi-stable rapid closing grasping, ensure that the grasped object is not damaged, and sense various physical properties of the object after grasping.

[0057] Specific embodiments of the present invention are further described below.

[0058] like Figure 1As shown, this embodiment provides an end effector based on bi-stable multi-sensor fusion, which includes a sensing gripper device 1, a grasping force control device 2, a bi-stable control device 3, a shell 4 and a depth sensing element 5. There are two sensing gripper devices 1, which are symmetrically arranged at the front end of the bi-stable control device 3. The opening and closing of the two sensing gripper devices 1 are controlled by the bi-stable control device 3. There are two grasping force control devices 2, which are respectively arranged on the back of the sensing gripper device 1. The shell 4 is arranged on the outside of the bi-stable control device 2 to surround the bi-stable control device 2. The depth sensing element 5 is arranged at the upper end and the front end of the shell 4 to sense the depth of the long distance and the depth information of the close distance.

[0059] After the end effector of this embodiment adopts the above structure, it can realize the rapid and non-destructive grasping of highly moving objects and the perception of various physical properties of the objects after grasping, and has a high degree of automation and intelligence.

[0060] like Figures 1 to 4 As shown, the sensing gripper device 1 is used to grasp high-speed moving objects and perceive the physical properties of the grasped objects. There are two sensing gripper devices 1, and the two sensing gripper devices 1 are symmetrically arranged. Each sensing gripper device 1 includes a force control component and other components. The force control component includes a linear bearing 7, a first force control linear plate 8, a first force control plate 9, a sensing film 10, a first roller guide 12, a TPU belt 13, a second force control plate 14, a second force control linear plate 15, a first pressure sensor 16, a second roller guide 17 and a second pressure sensor 18; the other components include a gripper base 6, a photoelectric switch 11, a tension spring support 19, an endoscope camera 20, a soft mirror film 21, a red LED light strip 22, a green LED light strip 23 and a blue LED light strip 24, and the viewing direction of the endoscope camera 20 is facing the soft mirror film 21, and the two sensing gripper devices 1 are independent of each other.

[0061] The clamping jaw base 6 is connected to the front end of the two-stable control device 3, the soft mirror film 21 is installed on the inner side plane of the clamping jaw base 6, and the endoscope camera 20 is installed on the inner rear side of the clamping jaw base 6. The viewing angle is sideways to the soft mirror film. The use of the mirror reflection principle is conducive to reducing the space occupied by the endoscope camera 20, thereby reducing the overall size of the clamp; the red LED light strip 22, the green LED light strip 23, and the blue LED light strip 24 are installed on the front, upper, and lower slopes of the inside of the clamping jaw base 6; the first ball guide rail 12 is installed on the inner front side of the clamping jaw base 6, and the second ball guide rail 17 is installed on the inner rear side of the clamping jaw base 6. The first force control plate 9 and the second force control plate 14 are coaxially connected through a rotating pin, and the rotating The pin is connected to the moving block on the first roller guide 12 and the second roller guide 17; one side of the first force-controlled linear plate 8 and the second force-controlled linear plate 15 is coaxially connected to the first force-controlled plate 9 and the second force-controlled plate 14 through a rotating pin, and the other side is connected to the upper and lower sides of the inner part of the clamping jaw base 6 through a linear bearing 7 with a protruding outlet so that it can move linearly. The whole is installed on the empty plane of the clamping jaw base 6. A protruding cylinder is provided in the middle of each of the two force-controlled linear plates to cooperate with the corresponding linear bearing. In addition, two protruding rectangular blocks can be provided on both sides of the cylinder to cooperate with the two rectangular openings of the upper and lower side plates of the clamping jaw base 6 to achieve a supporting effect and ensure the linear motion of the force-controlled linear plate; the first roller guide 12 When the moving block on the first and second roller guide rails 17 is controlled by the grasping force control device 2 to move in the direction of opening the clamping jaws, the first force control plate 9 and the second force control plate 14 can rotate around the coaxial connection (the rotation axis is parallel to the upper and lower sides of the clamping jaw base 6) under the drive of the moving block, so that the first force control plate 9 and the second force control plate 14 form an inwardly concave angle (concave toward the back of the sensing clamping jaw device 1); an elastic member such as a TPU belt 13 connects the first force control plate 9 and the second force control plate 14 to the edge of the clamping jaw base 6 and is bonded by glue. When the grasping force control device 2 releases the action on the moving block, the first force control plate 9 and the second force control plate 14 are reset to a flat state under the elastic force of the TPU belt 13. In this process, A force-controlled linear plate 8 and a second force-controlled linear plate 15 respectively perform linear motions toward or away from each other on the upper and lower sides to coordinate with the rotation of the first force-controlled plate 9 and the second force-controlled plate 14; a first pressure sensor 16 is mounted on the outside of the long strip of the first force-controlled plate 9, and a second pressure sensor 18 is mounted on the outside of the long strip of the second force-controlled plate 14; a sensing membrane 10 is mounted on the upper side of the first pressure sensor 16 and the second pressure sensor 18, and overlaps with the rectangle formed by the first force-controlled plate 9 and the second force-controlled plate 14; a photoelectric switch 11 is mounted on the outermost front end of the gripper base 6 to determine when the target enters the grasping range; a tension spring support 19 is mounted on the upper rear end and the lower rear end of the gripper base, and is coaxially mounted up and down.

[0062] After the sensing gripper device 1 of this embodiment adopts the above structure, it can realize the integration of the grasping and intelligent sensing capabilities of the sensing gripper 1, and cooperate with other devices to realize fast and lossless grasping and sensing.

[0063] like Figure 1 and Figure 5 As shown, the grasping force control device 2 is used to control the retraction and recovery of the force control component inside the sensing clamping device 1 during the grasping operation. There are two grasping force control devices 2, and the two grasping force control devices are respectively arranged on the back of the two sensing clamping devices 1. The grasping force control device 2 includes a brushless servo motor 25, a flange connector 26, a first steel wire rope 27, a first winding block 28, a second winding block 29 and a second steel wire rope 30.

[0064] The brushless servo motor 25 is directly installed on the outer back of the sensing clamping device 1; the flange connector 26 is installed on the upper side of the brushless servo motor 25; the first winding block 28 and the second winding block 29 are installed on the outer sides of the two side surfaces of the flange connector 26; one end of the first steel wire rope 27 is connected to the first winding block 28 and the flange connector 26 with screws, and the other end enters the interior of the clamping base 6 through the back channel of the sensing clamping device 1 and is connected to the moving block on the first ball guide rail 12. One end of the second steel wire rope 30 is connected to the second winding block 29 and the flange connector 26 with screws, and the other end enters the interior of the clamping base 6 through the back channel of the sensing clamping device 1 and is connected to the moving block on the second ball guide rail 17. By driving the brushless servo motor 25 to rotate, the outward pulling amount of the first steel wire rope 27 and the second steel wire rope 30 is controlled, so that the moving blocks on the first ball guide rail 12 and the second roller guide rail 17 are moved to realize force control operation during grasping. When the brushless servo motor 25 rotates to tighten the wire rope, it pulls the wire rope outward, thereby pulling the moving block of the roller guide toward the back of the clamping jaw base 6, so that the first force control plate 9 and the second force control plate 14 form an inwardly concave angle. When the brushless servo motor 25 relaxes the wire rope, the first force control plate 9 and the second force control plate 14 can restore to a straight state under the action of the elastic member, thereby switching the first force control plate 9 and the second force control plate 14 between the straight state and the concave state.

[0065] After the grasping force control device 2 of this embodiment adopts the above structure, it can adjust the grasping force of the sensing clamping device 1 performing the grasping work, ensuring the demand for lossless grasping, and the overall degree of intelligence is high.

[0066] like Figure 1 and Figure 6As shown, the bi-stable control device 3 is used to control the rapid opening and closing of the sensing clamping device 1. The bi-stable control device 3 is arranged at the rear end of the sensing clamping device 1 and is symmetrical with the two sensing clamping devices. The bi-stable control device includes a first damping hinge 31, a first steering block 32, a cylinder 33, a second steering block 34, a second damping hinge 35, a second connecting rod 36, a moving block 37, a linear guide rail 38, an electromagnet 39, a base 40, a magnetic patch 41, a first connecting rod 42, a first tension spring 43 and a second tension spring 44.

[0067] There are two linear guide rails 38, which are installed in parallel on the upper side of the bottom plate inside the base 40. The moving block 37 is installed on the upper side of the sliders of the two linear guide rails 38. The magnetic patch 41 is installed on the rear side of the moving block 37, facing the rear end of the base 40; the cylinder 33 is installed on the front end plate inside the base 40, and the telescopic rod is extended and retracted toward the rear end of the base and is set at the front end of the moving block 37; the electromagnet 39 is installed on the rear end plate inside the base 40, facing the magnetic patch 41; the first variable damping hinge 31 and the second variable damping hinge 35 are installed on the front end surface of the outside of the base 40, and are installed symmetrically on the left and right; the first steering block 32 and the first variable The movable end of the damping hinge 31 is connected, the long end of the first connecting rod 42 and the first steering block 32 are coaxially connected through a rotating pin, and the short end and the moving block 37 are coaxially connected through a rotating pin; the second steering block 34 and the second variable damping hinge 35 are connected at the movable end, the long end of the second connecting rod 36 and the second steering block 34 are coaxially connected through a rotating pin, and the short end and the moving block are coaxially connected through a rotating pin; the first tension spring 43 is installed between the tension spring pillars 19 on the upper side of the two sensing clamping devices 1, and the second tension spring 44 is installed between the tension spring pillars 19 on the lower side of the two sensing clamping devices 1, and the bi-stable state operation is realized through the energy storage characteristics of the tension spring.

[0068] After the bi-stable control device 3 of this embodiment adopts the above structure, it can enable the sensing gripper device 1 to quickly switch between the two stable states of the bi-stable state, thereby realizing the rapid closing of the sensing gripper device 1 and grasping high-speed moving objects.

[0069] like Figure 1 and Figure 7 As shown, the shell 4 is used to wrap the bi-stable control device 3 and to install the depth sensing element 5. The shell 4 is arranged outside the bi-stable control device 3 and is arranged as a whole at the rear end of the sensing clamping device 1. The shell 4 includes an upper shell 45, a pad 46 and a lower shell 47.

[0070] The upper shell 45 is installed on the upper outer side of the bistable control device 3 and is connected to the front and front end plates of the base 40 by screws; the lower shell 47 is installed on the lower outer side of the bistable control device 3 and is connected to the front and front end plates of the base 40 by screws, and the upper shell 45 and the lower shell 47 are locked and connected by screws at the rear side; the pad 46 is installed on the outer side of the front end plate of the base 40 and is connected to the lower shell 47 by screws.

[0071] After the housing 4 of this embodiment adopts the above structure, it can wrap the bi-stable control device 3, reducing the interference of the external environment on the bi-stable control device 3. The overall design is simple and beautiful, and provides an installation position for the depth sensing element 5.

[0072] like Figure 1 and Figure 8 As shown, the depth sensing element 5 is used to sense the position information of the target object being grasped. The depth sensing element 5 includes a depth camera 48 and a laser ranging sensor 49. The depth camera 48 is screwed to the upper end of the upper housing 45 and is used to sense the position of a high-speed moving object before it enters the grasping range of the sensing gripper 1. The laser ranging sensor 49 is screwed to the front end of the pad 46 and is used to sense the position of a high-speed object after it enters the grasping range of the sensing gripper 1. At this time, the depth camera 48 cannot observe the target object.

[0073] The depth sensing element 5 of this embodiment adopts the above structure, which can realize the position perception of the long-distance and close-distance grasping target objects, and has higher grasping accuracy.

[0074] The end effector of this embodiment operates as follows: it utilizes robotic arm control, coupled with a sensing gripper device, a grasping force control device, a bi-stable control device, a housing, and a depth sensing element, making it suitable for grasping and sensing various objects and possessing high grasping capabilities and a high degree of intelligence. A sensing gripper device with a concave grasping surface designed to mimic a trampoline and a pressure sensor can change the point, magnitude, and direction of force applied during rapid grasping, ensuring non-destructive grasping. The concave surface, combined with a TPU belt and a grasping force control device, controls the degree of concavity of the grasping surface and facilitates post-grasp sensing. A visual-tactile sensor is provided to sense the shape and texture of the grasped object after grasping, enhancing the end effector's intelligence. A tension spring, a pneumatic cylinder, and an electromagnet enable the sensing gripper device to rapidly switch between open and closed states, achieving bi-stable states and ensuring rapid grasping. A depth camera and a laser ranging sensor, combined with the robotic arm's motion prediction and planning algorithms, enable positioning and control of high-speed moving objects in midair, achieving a high degree of intelligence.

[0075] The end effector of the embodiment of the present invention can realize a non-destructive grasping method for high-speed moving objects, and the process may include:

[0076] In the preparation stage, the end effector is installed at the end of the robotic arm, and the electromagnet is energized to attract the moving block, so that the sensing gripper is in the maximum open state. At this time, the first tension spring and the second tension spring are in the stretched state;

[0077] During the grasping phase, the depth camera acquires the position information of high-speed moving objects, predicts the grasping position, and controls the robotic arm to drive the end effector to the predicted position. When the object to be grasped passes the front end of the intelligent gripper, that is, the infrared ray monitoring area of ​​the photoelectric switch, the electromagnet is de-energized, and the gripper quickly closes under the elastic potential energy of the first and second tension springs. At this time, the depth camera is in a blind spot for detecting high-speed moving objects, and the position data obtained by the laser ranging sensor is used to compensate for the movement of the robotic arm.

[0078] During the rapid closing of the sensing gripper, the pressure state of the sensing membrane surface is sensed by the pressure sensor, and the brushless servo motor of the grasping force control device is controlled to make the sensing membrane concave, dispersing the pressure on the target object to ensure non-destructive grasping.

[0079] After the grasping process is completed, the object sensing process is carried out. By controlling the brushless servo motor of the grasping force control device, the first and second steel wire ropes are relaxed. Under the action of the TPU tape, the sensing membrane returns to a flat state as the steel wire ropes relax. Pressure is applied to the object, and the texture and shape of the object are observed through the endoscopic camera. The weight is sensed by the pressure sensor to further determine the characteristics of the grasped object.

[0080] After finishing the grasping and sensing work, the cylinder extends the rod and pushes the moving block to the front of the electromagnet. At this time, the electromagnet is energized to attract the magnetic patch, maintain the end position of the moving block, and restore the sensing gripper to the open state.

[0081] like Figures 1 to 9 As shown, this embodiment also provides a grasping method, which is implemented based on the above-mentioned end effector and may include the following steps:

[0082] Step 1: The staff starts the end effector, the end effector is powered on, and initialization is performed: the cylinder extension rod is extended, pushing the moving block to the end, at which time the electromagnet is energized, adsorbing the magnetic patch installed on the rear end face of the moving block, fixing the moving block, opening the two sensing claws to the maximum angle, and stretching the tension spring; then the brushless servo motor of the grasping force control device returns to zero position, so that the wire rope is in a relaxed state; the red, green, and blue LED light strips are powered on and light up, completing initialization.

[0083] Step 2: The staff throws a random target object toward the end effector. The end effector's depth camera works to detect the position of the target object and feeds the position data information back to the industrial computer of the robotic arm. It predicts the grasping position and plans the movement path of the robotic arm, and controls the robotic arm to move to the target point.

[0084] Step 3: The end effector begins grasping. When the target object passes through the detection area between the two photoelectric switches at the front end of the sensing gripper, the laser ranging sensor activates, detecting the distance to the target object. This distance data is fed back to the robotic arm's industrial computer, which controls the robotic arm to adjust its posture so that the target object is centered in the gripper. Simultaneously, the electromagnet is de-energized, and the two sensing grippers, utilizing the elastic potential energy released by the tension spring, quickly close to grasp the object. When the object touches the sensing membrane, its trampoline-like design causes it to concave. The pressure sensor receives the pressure information, and the grasping force control device activates. The brushless servo motor rotates, tightening or loosening the wire rope, and the ball guide moves inward or outward of the sensing gripper, adjusting the degree of retraction of the gripping surface of the sensing gripper, controlling the pressure on the target surface, and ensuring non-destructive grasping.

[0085] Step 4: After the grasping is completed, the data feedback from the pressure sensor is used to determine whether the target object has been grasped successfully. If there is no pressure value feedback, the grasping is unsuccessful, and the first step of reset operation is performed to grasp again. If there is a pressure value in the feedback, the grasping is successful, and the target object perception work is carried out.

[0086] Step 5: The physical properties of the target object are sensed, the grasping force control device works, the brushless servo motor loosens the wire rope, and the sensing membrane is pressed against the surface of the target object. The endoscopic camera works and uses mirror reflection to capture the texture and shape of the pressed surface on the sensing membrane. The pressure sensor then feeds back the pressure value to estimate the weight of the object and make a judgment on the object.

[0087] Step 6: After completing the object perception and judgment, control the robotic arm to place the object at the specified location, perform the first step of initialization, and prepare for the next grasping work.

[0088] In summary, the end effector of the present invention is equipped with a sensing gripper device, a grasping force control device, a bi-stable control device, a shell and a depth sensing element, which can realize fast and non-destructive grasping of high-speed moving objects, and after grasping, it can perceive the characteristics of the grasped object through multi-sensor fusion, thereby realizing intelligent grasping of high-speed moving unknown objects.

[0089] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the inclusion of content in the background section is not an admission by the applicant that the prior art is present.

[0090] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these 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. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. An end effector based on bi-stable multi-sensor fusion, characterized in that: The invention comprises a pair of sensing claw devices, a grasping force control device, a bi-stable control device and a depth sensing element, wherein the sensing claw device comprises a sensing membrane and a pressure sensor, the bi-stable control device is coupled to the sensing claw device through an elastic mechanism, the grasping force control device is coupled to the sensing membrane, the bi-stable control device overcomes the elastic force to open the pair of sensing claw devices at the beginning, and releases the elastic force to close the pair of sensing claw devices when the depth sensing element senses that the target object enters the grasping range, and the grasping force control device controls the sensing membrane to retract before the grasping is successful so as to grasp the target object non-destructively according to the pressure state of the sensing membrane surface sensed by the pressure sensor, and releases the sensing membrane when the grasping is successful. The membrane applies pressure to the target object; the bi-stable control device is arranged at the rear end of the sensing clamping device, and the bi-stable control device includes a cylinder, a first linear guide rail, a second linear guide rail, an electromagnet, a first tension spring, a second tension spring, a first connecting rod, a second connecting rod, a moving block, a magnetic patch, a first variable damping hinge, a second variable damping hinge, a first steering block, a second steering block, a pad and a base; the first linear guide rail and the second linear guide rail are installed in parallel on the upper side of the bottom plate inside the base, the moving block is installed on the upper side of the first linear guide rail and the second linear guide rail slider, and the magnetic patch is installed on the rear side of the moving block, facing the rear end of the base; the cylinder is installed on the front end plate inside the base, the telescopic rod is telescopically extended toward the rear end of the base, and is arranged at the front end of the moving block; The electromagnet is installed on the rear end plate inside the base, facing the magnetic patch; the first variable damping hinge and the second variable damping hinge are installed on the front end surface outside the base, and are installed symmetrically on the left and right; the first steering block is connected to the movable end of the first variable damping hinge, the long end of the first connecting rod and the first steering block are coaxially connected by a rotating pin, and the short end and the moving block are coaxially connected by a rotating pin; the second steering block is connected to the movable end of the second variable damping hinge, the long end of the second connecting rod and the second steering block are coaxially connected by a rotating pin, and the short end and the moving block are coaxially connected by a rotating pin; the first tension spring is installed between the tension spring fixings on the upper sides of the two sensing jaws, and the second tension spring is installed between the tension spring fixings on the lower sides of the two sensing jaws.

2. The end effector according to claim 1, wherein: The sensing clamping device also includes a first force control plate, a second force control plate, a first force control linear plate, a second force control linear plate, a first ball guide, a second ball guide and a clamping base; the first ball guide is installed on the front side of the interior of the clamping base, and the second ball guide is installed on the rear side of the interior of the clamping base, the first force control plate and the second force control plate are coaxially connected by a rotating pin, and the rotating pin is connected to the moving blocks on the first ball guide and the second ball guide; one side of the first force control linear plate and the second force control plate is coaxially connected to the first force control plate and the second force control plate by a rotating pin, and the other side is connected to the upper side and the lower side of the interior of the clamping base in a linearly movable manner, and the whole is installed on the empty plane of the clamping base; the sensing membrane is installed on the upper side of the first pressure sensor and the second pressure sensor, and coincides with the rectangle formed by the first force control plate and the second force control plate; The movement of the first ball guide rail and the second ball guide rail adjusts the retraction degree of the sensing film; the first force control plate and the second force control plate are connected to the edge of the clamping claw base through an elastic member.

3. The end effector according to claim 2, wherein: The elastic member is an elastic band.

4. The end effector according to claim 2, wherein: The pressure sensor includes a first pressure sensor and a second pressure sensor. The first pressure sensor is installed on the outside of the first force control plate, and the second pressure sensor is installed on the outside of the second force control plate. The sensing membrane is installed on the upper side of the first pressure sensor and the second pressure sensor.

5. The end effector according to any one of claims 1 to 4, characterized in that: The sensing gripper device further includes a visual shape sensing module, which projects pattern light onto the sensing film pressed on the target object and takes a picture to sense the shape of the target object.

6. The end effector according to claim 5, wherein: The visual shape perception module includes an endoscopic camera, a red LED light strip, a green LED light strip, and a blue LED light strip; the red LED light strip, the green LED light strip, and the blue LED light strip are installed on the front, upper, and lower slopes inside the gripper base.

7. The end effector according to claim 6, wherein: It also includes a flat soft mirror film installed on the inner side of the clamping jaw base, and the endoscope camera is installed on the inner rear side of the clamping jaw base, with a viewing angle sideways to the soft mirror film.

8. The end effector according to any one of claims 2 to 4, characterized in that: The two grasping force control devices are respectively arranged on the outer back of the two sensing jaws, and the grasping force control devices include a brushless servo motor, a flange connector, a first winding block, a second winding block, a first steel wire rope and a second steel wire rope; the brushless servo motor is directly installed on the outer back of the sensing jaw; the flange connector is installed on the upper side of the brushless servo motor; the first winding block and the second winding block are installed on the outer sides of the two side surfaces of the flange connector; one end of the first steel wire rope is connected to the first winding block and the flange connector, and the other end is connected to the first ball guide rail through the back channel of the sensing jaw; one end of the second steel wire rope is connected to the second winding block and the flange connector, and the other end is connected to the second ball guide rail through the back channel of the sensing jaw. The brushless servo motor is driven to rotate to control the outward pulling amount of the steel wire rope, so that the ball guide rail moves backward to realize the force control operation during grasping.

9. The end effector according to any one of claims 1 to 4, characterized in that: The depth sensing element includes a depth camera and a laser ranging sensor; the depth camera is installed at the upper end of the housing of the bi-stable control device; the laser ranging sensor is arranged at the front end of the bi-stable control device, and a gap is formed between the pair of sensing clamping devices to provide a field of view for the laser ranging sensor.

10. The end effector according to claim 9, wherein: The sensing gripper device includes a photoelectric switch installed at the front end, which is used to judge the timing when the target object enters the grasping range and trigger the laser ranging sensor to work.

11. A robot, characterized in that: The device comprises the end effector according to any one of claims 1 to 10.

12. A method for grasping an object using the end effector according to any one of claims 1 to 10.

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