Multifunctional grabbing robot based on Mecanum wheel

Abstract

The application discloses a multifunctional grabbing robot based on Mecanum wheels, two mirror image reconfigurable opening and closing mechanisms are symmetrically installed on a base and can rotate horizontally, two mirror image finger centering mechanisms are installed on the base and the reconfigurable opening and closing mechanisms, two mirror image Mecanum wheel moving finger mechanisms are respectively fixedly connected to rotating structures of the reconfigurable opening and closing mechanisms and can rotate around shafts, an under-actuated fixed finger mechanism is rotationally connected to the base and the distance between the under-actuated fixed finger mechanism and the base can be adjusted, the Mecanum wheel moving finger mechanism comprises two knuckles, a left-hand rotating Mecanum wheel is installed on the first knuckle, a right-hand rotating Mecanum wheel is installed on the second knuckle, the first knuckle and the second knuckle are rotationally connected through a joint shaft, and the left-hand rotating Mecanum wheel and the right-hand rotating Mecanum wheel respectively control the rotating direction and the rotating speed through motors. The application can control the position of an object after the object is grabbed, can switch working modes and complete various tasks such as pipeline passing and exploration.

Description

Technical Field

[0001] This invention relates to the fields of pipeline exploration and robotics, and more particularly to a multi-functional grasping robot based on a Mecanum wheel. Background Technology

[0002] The human hand is one of nature's most versatile tools. It can use the covering action of its five fingers to achieve a stable grasping effect on objects of different shapes, and adjust its position and posture within the grasping hand to perform hand manipulations. In robotics research, "dexterity" usually refers to manipulating an object with the hand. Currently, most dexterous hands on the market can only grasp certain objects, and due to their complex drive structures, they suffer from low grasping stability and are unable to perform hand manipulations of objects.

[0003] Furthermore, pipelines are widely used as an effective means of material transportation in general industry, nuclear facilities, oil and gas, and military equipment. To improve pipeline lifespan and prevent leaks and other accidents, effective pipeline inspection and maintenance are essential, leading to the development of pipeline robots. However, current pipeline robots generally suffer from poor pipeline maneuverability and adaptability, limited movement patterns, and complex drive control.

[0004] Currently, most dexterous robotic hands primarily employ a single grasping function. When adjustments to the position and orientation of the grasped object are needed within the hand, other tools must be used for assistance. Furthermore, there is no device capable of detaching from the robotic arm to become a pipeline robot. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a multi-functional grasping robot based on Mecanum wheels.

[0006] The specific technical solution is as follows:

[0007] A multi-functional grasping robot based on Mecanum wheels includes: a base, a Mecanum wheel moving finger mechanism, an underactuated fixed finger mechanism, a reconfigurable opening and closing mechanism, and a finger centering mechanism; two mirror-image reconfigurable opening and closing mechanisms are symmetrically mounted on the base and can rotate horizontally; there are two mirror-image finger centering mechanisms, each mounted on the base and the reconfigurable opening and closing mechanisms; there are two mirror-image Mecanum wheel moving finger mechanisms, each fixedly connected to the rotating structure of the reconfigurable opening and closing mechanism, and the rotating structure can rotate freely around an axis; the underactuated fixed finger mechanism is rotatably connected to the base, and the distance between the fixed finger mechanism and the base can be adjusted; the underactuated fixed finger mechanism and the two Mecanum wheel moving finger mechanisms form a triangular configuration.

[0008] The Mecanum wheel moving finger mechanism includes two finger joints, wherein a left-handed Mecanum wheel is installed on the first finger joint and a right-handed Mecanum wheel is installed on the second finger joint. The first finger joint and the second finger joint are rotatably connected by a joint shaft. The left-handed Mecanum wheel and the right-handed Mecanum wheel are controlled by a motor to control their rotation direction and speed, respectively.

[0009] Furthermore, the Mecanum wheel moving mechanism includes: a first fixed plate, a second fixed plate, a third fixed plate, a fourth fixed plate, a left-handed Mecanum wheel, a right-handed Mecanum wheel, a large synchronous belt pulley, a small synchronous belt pulley, a first synchronous belt, a second synchronous belt, a third synchronous belt, two TT motors, a shaft gear, a joint shaft, a Mecanum wheel shaft, a small spring, a gear, and a synchronous belt pulley fixing plate;

[0010] The first knuckle includes: a first fixing plate, a second fixing plate, a left-handed Mecanum wheel, and a Mecanum wheel axle; the first fixing plate and the second fixing plate are mirror images of each other and are installed opposite each other; the left-handed Mecanum wheel is fixedly connected to the Mecanum wheel axle, one end of the Mecanum wheel axle is mounted on the second fixing plate through a rolling bearing, and the other end is provided with a large synchronous pulley, which is mounted on the first fixing plate through a rolling bearing, and the large synchronous pulley is in close contact with the side of the left-handed Mecanum wheel;

[0011] One end of the joint shaft is mounted on the third fixed plate via a rolling bearing. A small synchronous pulley is fixedly connected to this end. The small synchronous pulley on the joint shaft is connected to the large synchronous pulley corresponding to the left-hand Mecanum pulley via a first synchronous belt. A rolling bearing is fitted and fixedly connected in the middle of the joint shaft. The rolling bearing is embedded in the first fixed plate and the second fixed plate respectively. The other end of the joint shaft passes through the fourth fixed plate and is fixedly connected to one end of the synchronous pulley fixed plate via a rolling bearing. A large synchronous pulley is fixedly connected to this end of the joint shaft. The two ends of the small spring are fixedly connected to two metal optical shafts. The two metal optical shafts are arranged around the joint shaft and parallel to it. The two ends of one metal optical shaft are mounted on the first fixed plate and the second fixed plate via rolling bearings respectively. The two ends of the other metal optical shaft are mounted on the third fixed plate and the fourth fixed plate via rolling bearings respectively.

[0012] The second joint includes: a third fixed plate, a fourth fixed plate, a right-hand Mecanum wheel, and a Mecanum wheel axle; the third fixed plate and the fourth fixed plate are mirror images of each other and are installed opposite each other; between the third fixed plate and the fourth fixed plate, from top to bottom, are arranged a right-hand Mecanum wheel, a gear with a shaft, and a TT motor; two TT motors are fixedly connected to the third fixed plate, wherein the TT motor whose output shaft is away from the joint shaft has a small synchronous pulley fixedly connected to its output shaft, and the small synchronous pulley is fixedly connected to the other end of the synchronous pulley fixed plate through a rolling bearing; the small synchronous pulley on the output shaft of the TT motor and the large synchronous pulley on the joint shaft are connected by a third synchronous belt, which is located between the fourth fixed plate and the synchronous pulley fixed plate;

[0013] The TT motor, with its output shaft close to the joint shaft, has a gear fixedly connected to its output shaft. This gear meshes with a belt-driven gear. One end of the belt-driven gear is fixedly connected to a small synchronous pulley and mounted on a third fixed plate via a rolling bearing. The other end of the belt-driven gear is mounted on a fourth fixed plate via a rolling bearing. The right-hand Mecanum wheel is fixedly connected to a Mecanum wheel shaft. One end of the Mecanum wheel shaft is mounted on the fourth fixed plate via a rolling bearing, and the other end is equipped with a large synchronous pulley, which is mounted on the third fixed plate via a rolling bearing. The large synchronous pulley is in close contact with the side of the right-hand Mecanum wheel. The small synchronous pulley on the belt-driven gear and the corresponding large synchronous pulley on the right-hand Mecanum wheel are connected by a second synchronous belt.

[0014] Furthermore, the first knuckle containing the left-handed Mecanum wheel has an angle in the vertical direction relative to the second knuckle containing the right-handed Mecanum wheel.

[0015] Furthermore, the underactuated fixing mechanism includes: an omnidirectional wheel fixing plate, an omnidirectional wheel, an omnidirectional wheel axle, a first link, a second link, a mirror image of the second link, and a large spring; there are two omnidirectional wheel fixing plates, which are mirror images of each other and installed opposite each other; two omnidirectional wheel axles are installed between the two omnidirectional wheel fixing plates and can rotate freely; the omnidirectional wheel axles are arranged perpendicularly to the omnidirectional wheel fixing plates and are located at the end away from the connection between the underactuated fixing mechanism and the base; an omnidirectional wheel is sleeved on the omnidirectional wheel axle and can rotate freely on the omnidirectional wheel axle;

[0016] One end of the first connecting rod is rotatably connected to the base via a rolling bearing, and the other end is a circular boss on which a slotted rolling bearing is mounted. It is installed in a groove in the middle section of the two omnidirectional wheel fixing plates and can roll freely. The second connecting rod and the mirror image of the second connecting rod are mirror images of each other and are installed close to each other. The middle of the second connecting rod and the mirror image of the second connecting rod are both provided with grooves for installing the first connecting rod. When the second connecting rod and the mirror image of the second connecting rod are installed close to each other, the cavity formed by the two grooves is adapted to the width and thickness of the first connecting rod and allows the first connecting rod to rotate freely. The second connecting rod, the first connecting rod, and the mirror image of the second connecting rod are rotatably connected via a metal optical shaft. One end of the second connecting rod and the mirror image of the second connecting rod are rotatably connected to the base via a metal optical shaft. The other end is rotatably connected to the end of the omnidirectional wheel fixing plate near the connection with the base via a metal optical shaft. One end of a large spring is fitted onto the metal optical shaft at this end, and the other end of the large spring is fixed to the circular boss of the first connecting rod. In the initial state, the first connecting rod is located at the end of the groove away from the omnidirectional wheel.

[0017] Furthermore, holes are made at the intersection of the second link, the first link, and the mirror image of the second link, and rolling bearings are installed thereon. The metal optical shaft passes through these three rolling bearings. The cooperation between the rolling bearings and the metal optical shaft realizes the rotational connection of the first link, the second link, and the mirror image of the second link. The rotational connection between the second link and the mirror image of the second link and the base, and the rotational connection between the second link and the mirror image of the second link and the omnidirectional wheel fixing plate are also realized through the cooperation between the rolling bearings and the metal optical shaft.

[0018] Furthermore, the reconfigurable opening and closing mechanism includes: a first opening and closing gear, a second opening and closing gear, a crossed roller bearing, a servo motor, and a swing arm; the servo motor is fixedly connected to the base, and the first opening and closing gear is fastened to the servo motor's rudder; a countersunk hole is formed on the upper surface of the horizontal portion of the base, and the crossed roller bearing is fixedly connected to the countersunk hole of the base through its outer ring countersunk hole; a countersunk hole is formed on the lower surface of the swing arm at the corresponding position of the crossed roller bearing for installation, and a through hole is formed at the corresponding position of the inner ring of the crossed roller bearing; the second opening and closing gear is close to the upper surface of the swing arm and is fastened to the inner ring threaded hole of the crossed roller bearing through the through hole of the swing arm, and the second opening and closing gear meshes with the first opening and closing gear.

[0019] Furthermore, the servos of the two reconfigurable opening and closing mechanisms always move in opposite directions.

[0020] Furthermore, the finger centering mechanism includes: a first centering gear, a second centering gear, a third centering gear, a crossed roller bearing, and a servo motor; the servo motor is fixedly connected to the base, and the first centering gear is fastened to the servo motor's rudder, with the first centering gear located directly above the second opening / closing gear; a two-section stepped shaft is fixedly connected to the middle of the swing arm, the stepped shaft does not interfere with the second opening / closing gear, the diameter of the section of the stepped shaft near the swing arm is larger than the other section, and the height is the same as the second opening / closing gear; the second centering gear is installed on the section of the stepped shaft of the swing arm away from the swing arm, and the second centering gear meshes with the first centering gear; the crossed roller bearing is fixedly connected to a countersunk hole opened on the upper surface of the swing arm through its outer ring countersunk hole, the third centering gear is fixedly connected to the crossed roller bearing and meshes with the second centering gear; the upper surface of the third centering gear has an integrally designed connector for fixedly connecting with the Mecanum wheel finger movement mechanism.

[0021] Furthermore, the servos of the two finger-aligning mechanisms always move in opposite directions.

[0022] The beneficial effects of this invention are:

[0023] (1) The present invention incorporates the Mecanum wheel mechanism into the Mecanum wheel moving finger mechanism, which can grasp objects of regular shape and perform position control within the robot arm, thereby improving the robot's operation efficiency.

[0024] (2) This invention can be carried out independently of the robotic arm. By rotating the Mecanum wheel to move the orientation of the finger mechanism, the working mode can be switched to complete various tasks such as passage and exploration in the pipeline.

[0025] (3) The device of the present invention has a simple and complete structure, high efficiency and good reliability. Attached Figure Description

[0026] Figure 1 This is a three-dimensional schematic diagram of the multi-functional grasping robot based on the Mecanum wheel of the present invention from one angle.

[0027] Figure 2 This is a three-dimensional schematic diagram of the multi-functional grasping robot based on the Mecanum wheel of the present invention from another angle.

[0028] Figure 3 This is a three-dimensional schematic diagram of the Mecanum wheel moving finger mechanism of the present invention.

[0029] Figure 4 This is a three-dimensional schematic diagram of the tire connection relationship inside the Mecanum wheel moving finger mechanism of the present invention.

[0030] Figure 5 This is a three-dimensional schematic diagram of the underactuated fixed finger mechanism of the present invention.

[0031] Figure 6 This is a schematic diagram of the internal connection relationship of the underactuated fixed finger mechanism of the present invention.

[0032] Figure 7 This is a three-dimensional schematic diagram of the reconfigurable opening and closing mechanism of the present invention after installation.

[0033] Figure 8 This is a three-dimensional schematic diagram of the reconfigurable opening and closing mechanism of the present invention when the swing arm on one side is installed.

[0034] Figure 9 This is a three-dimensional schematic diagram of the finger alignment mechanism of the present invention after installation.

[0035] In the diagram, the components are: base 1, Mecanum wheel moving mechanism 2, first fixed plate 2-1, second fixed plate 2-2, third fixed plate 2-3, fourth fixed plate 2-4, left-hand Mecanum wheel 2-5, right-hand Mecanum wheel 2-6, large synchronous belt pulley 2-7, small synchronous belt pulley 2-8, first synchronous belt 2-9, second synchronous belt 2-10, third synchronous belt 2-11, TT motor 2-12, belt-driven gear 2-13, joint shaft 2-14, motor output shaft 2-15, Mecanum wheel shaft 2-16, small spring 2-17, gear 2-18, and synchronous... 2-19 Pulley fixing plate, 3 underactuated fixed finger mechanism, 3-1 Omnidirectional wheel fixing plate, 3-2 Omnidirectional wheel, 3-3 Omnidirectional wheel axle, 3-4 First link, 3-5 Second link, 3-6 Second link mirror image, 3-7 Large spring, 4 Reconfigurable opening and closing mechanism, 4-1 First opening and closing gear, 4-2 Second opening and closing gear, 5 Finger centering mechanism, 5-1 First centering gear, 5-2 Second centering gear, 5-3 Third centering gear, 6 Metal optical shaft, 7 Rolling bearing, 8 In-groove rolling bearing, 9 Crossed roller bearing, 10 Servo, 11 Swing arm, 12 Shim. Detailed Implementation

[0036] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The objectives and effects of the present invention will become clearer as a result. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0037] like Figure 1 and Figure 2 As shown, a multi-functional grasping robot based on Mecanum wheels includes: a base 1, a Mecanum wheel moving finger mechanism 2, an underactuated fixed finger mechanism 3, a reconfigurable opening and closing mechanism 4, and a finger alignment mechanism 5. The base 1 includes two detachable upper and lower parts. Two mirror-image reconfigurable opening and closing mechanisms 4 are symmetrically installed on the lower half of the base 1 and can rotate horizontally. Two mirror-image finger alignment mechanisms 5 are symmetrically installed on the upper half of the base 1 and the reconfigurable opening and closing mechanisms 4. Two mirror-image Mecanum wheel moving finger mechanisms 2 are respectively installed on the end rotating structure of the finger alignment mechanism 5 and can rotate around an axis and achieve joint bending. The underactuated fixed finger mechanism 3 is installed in the rear bearing groove of the base 1 through bearing cooperation, and the underactuated fixed finger mechanism 3 and the two Mecanum wheel moving finger mechanisms 2 form a triangular state.

[0038] like Figure 3 , Figure 4As shown, each Mecanum wheel moving mechanism 2 includes: a first fixed plate 2-1, a second fixed plate 2-2, a third fixed plate 2-3, a fourth fixed plate 2-4, a left-hand Mecanum wheel 2-5, a right-hand Mecanum wheel 2-6, a large synchronous belt pulley 2-7, a small synchronous belt pulley 2-8, a first synchronous belt 2-9, a second synchronous belt 2-10, a third synchronous belt 2-11, a TT motor 2-12, a belt-driven gear 2-13, a joint shaft 2-14, a motor output shaft 2-15, a Mecanum wheel shaft 2-16, a small spring 2-17, a gear 2-18, and a synchronous belt pulley fixing plate 2-19.

[0039] The first fixing plate 2-1 and the second fixing plate 2-2 are mirror images of each other and installed opposite each other. The third fixing plate 2-3 and the fourth fixing plate 2-4 are also mirror images of each other and installed opposite each other. Between the first fixing plate 2-1 and the third fixing plate 2-3 on the same side and the second fixing plate 2-2 and the fourth fixing plate 2-4 on the other side, a left-hand Mecanum wheel 2-5, a joint shaft 2-14, a right-hand Mecanum wheel 2-6, a shaft gear 2-13, and two TT motors 2-12 are arranged sequentially from top to bottom. The left-hand Mecanum wheel 2-5 is fitted and fixedly connected to the Mecanum wheel shaft 2-16. One end of the Mecanum wheel shaft 2-16 is mounted on the second fixing plate 2-2 through a rolling bearing 7. The other end of the Mecanum wheel shaft 2-16 is mounted on the first fixing plate 2-1 through a rolling bearing 7, and a large synchronous pulley 2-7 is fitted and fixedly connected to the outer circumference of this end. The large synchronous pulley 2-7 is in close contact with the side of the left-hand Mecanum wheel 2-5. One end of the joint shaft 2-14 is mounted on the third fixed plate 2-3 via a rolling bearing 7. A small synchronous pulley 2-8 is fitted and fixedly connected to this end. The small synchronous pulley 2-8 on the joint shaft 2-14 is connected to the large synchronous pulley 2-7 corresponding to the left-hand Mecanum pulley 2-5 via a first synchronous belt 2-9. The first synchronous belt 2-9 cooperates with the small synchronous pulley 2-8 and the large synchronous pulley 2-7 corresponding to the left-hand Mecanum pulley 2-5 on the joint shaft 2-14, thereby realizing the synchronous rotation of the small synchronous pulley 2-8 and the large synchronous pulley 2-7. A rolling bearing 7 is fitted and fixedly connected to the middle of the joint shaft 2-14. The rolling bearing 7 is embedded in the first fixed plate 2-1 and the second fixed plate 2-2 respectively. The other end of the joint shaft 2-14 passes through the fourth fixed plate 2-4 and is fixedly connected to one end of the synchronous pulley fixed plate 2-19 via the rolling bearing 7. A large synchronous pulley 2-7 is fitted and fixedly connected to this end of the joint shaft 2-14. The first knuckle containing the left-handed Mecanum wheel 2-5 is set to have a certain angle in the vertical direction compared to the second knuckle containing the right-handed Mecanum wheel 2-6.

[0040] The two ends of the small spring 2-17 pass through two metal optical shafts 6 respectively. The two metal optical shafts 6 are arranged around and parallel to the joint shaft 2-14. The two ends of one metal optical shaft 6 are respectively mounted on the first fixed plate 2-1 and the second fixed plate 2-2 through rolling bearings 7. The two ends of the other metal optical shaft 6 are respectively mounted on the third fixed plate 2-3 and the fourth fixed plate 2-4 through rolling bearings 7. The rolling bearings 7 are used to reduce rotational friction.

[0041] There are two TT motors 2-12, fixed in opposite parallel directions within a groove on the inner side of the third fixed plate 2-3. The TT motor 2-12 whose output shaft is away from the joint shaft 2-14 has a small synchronous pulley 2-8 fixedly mounted on its output shaft 2-15. The motor output shaft 2-15 transmits torque to the small synchronous pulley 2-8, which is fixed to the other end of the synchronous pulley fixing plate 2-19 via a rolling bearing 7. The small synchronous pulley 2-8 on the motor output shaft 2-15 and the large synchronous pulley 2-7 on the joint shaft 2-14 are connected by a third synchronous belt 2-11, located between the fourth fixed plate 2-4 and the synchronous pulley fixing plate 2-19. The third synchronous belt 2-11, in conjunction with the small synchronous pulley 2-8 on the motor output shaft 2-15 and the large synchronous pulley 2-7 on the joint shaft 2-14, enables synchronous rotation of the small synchronous pulley 2-8 and the large synchronous pulley 2-7.

[0042] The TT motor 2-12, whose output shaft is close to the joint shaft 2-14, has a gear 2-18 fixedly connected to its output shaft. The gear 2-18 meshes with the shaft gear 2-13. A small synchronous pulley 2-8 is fitted and fixedly connected to one end of the shaft gear 2-13. This end is mounted on the third fixed plate 2-3 through a rolling bearing 7. The other end of the shaft gear 2-13 is mounted on the fourth fixed plate 2-4 through a rolling bearing 7. Since the gear 2-18 meshes with the shaft gear 2-13, the torque of the TT motor 2-12 is transmitted to the shaft gear 2-13, thereby realizing the control of the small synchronous pulley 2-8 on the shaft gear 2-13. A right-hand Mecanum pulley 2-6 is positioned between the shaft gear 2-13 and the joint shaft 2-14. The right-hand Mecanum pulley 2-6 is fitted and fixedly connected to the Mecanum pulley shaft 2-16. One end of the Mecanum pulley shaft 2-16 is mounted on the fourth fixed plate 2-4 via a rolling bearing 7, and the other end is mounted on the third fixed plate 2-3 via a rolling bearing 7. A large synchronous pulley 2-7 is fitted and fixedly connected to the outer circumference of this end, and the large synchronous pulley 2-7 is in close contact with the side of the right-hand Mecanum pulley 2-6. The small synchronous pulley 2-8 on the shaft gear 2-13 and the corresponding large synchronous pulley 2-7 of the right-hand Mecanum pulley 2-6 are connected via a second synchronous belt 2-10. The second synchronous belt 2-10 engages with the small synchronous pulley 2-8 on the shaft gear 2-13 and the corresponding large synchronous pulley 2-7 of the right-hand Mecanum pulley 2-6, thereby achieving synchronous rotation of the small synchronous pulley 2-8 and the large synchronous pulley 2-7.

[0043] like Figure 5 , Figure 6 As shown, the underactuated fixing mechanism 3 includes: an omnidirectional wheel fixing plate 3-1, an omnidirectional wheel 3-2, an omnidirectional wheel axle 3-3, a first connecting rod 3-4, a second connecting rod 3-5, a mirror image of the second connecting rod 3-6, and a large spring 3-7. There are two omnidirectional wheel fixing plates 3-1, which are mirror images of each other and installed opposite each other. Two omnidirectional wheel axles 3-3 are mounted between the two omnidirectional wheel fixing plates 3-1 via bearings, and are arranged perpendicularly to the omnidirectional wheel fixing plates 3-1, located at the end furthest from the connection point between the underactuated fixing mechanism 3 and the base 1. The omnidirectional wheel axles 3-3 can rotate freely. Each omnidirectional wheel axle 3-3 is fitted with an omnidirectional wheel 3-2 and two washers 12. The washers 12 are tightly attached to both sides of the omnidirectional wheel 3-2. The function of the washers 12 is to prevent friction between the omnidirectional wheel 3-2 and the omnidirectional wheel fixing plate 3-1, allowing the omnidirectional wheel 3-2 to rotate freely on the omnidirectional wheel axle 3-3.

[0044] One end of the first connecting rod 3-4 is rotatably connected to the base 1 via a rolling bearing 7, and the other end is a circular boss on which a grooved rolling bearing 8 is mounted and installed in the groove opened in the middle section of the left and right omnidirectional wheel fixing plates 3-1. The left and right omnidirectional wheel fixing plates 3-1 are fastened, and the grooved rolling bearings 8 on both sides of the circular boss can roll freely in the groove. The second link 3-5 and the mirror image of the second link 3-6 are mirror images of each other and are installed close to each other. Grooves are formed in the middle of both the second link 3-5 and the mirror image of the second link 3-6 for mounting the first link 3-4. Holes are made at the intersections of the first link 3-4, the second link 3-5, and the mirror image of the second link 3-6, and rolling bearings 7 are installed at each. A metal shaft 6 passes through these three rolling bearings 7. The cooperation between the rolling bearings 7 and the metal shaft 6 enables the rotational connection of the first link 3-4, the second link 3-5, and the mirror image of the second link 3-6, and reduces rolling friction, making rotation smoother. When the second link 3-5 and the mirror image of the second link 3-6 are installed close to each other, the cavity formed by the two grooves matches the width and thickness of the first link 3-4, allowing the first link 3-4 to rotate freely. One end of the second link 3-5 and the mirror image of the second link 3-6 are rotatably connected to the base 1 through the cooperation of the rolling bearing 7 and the metal optical shaft 6; the other end is rotatably connected to the end of the omnidirectional wheel fixing plate 3-1 near the connection with the base 1 through the cooperation of the rolling bearing 7 and the metal optical shaft 6. One end of the large spring 3-7 is fitted onto the metal optical shaft 6 at this end, and the other end of the large spring 3-7 hooks onto the circular boss of the first link 3-4. In the initial state, the first link 3-4 is located at the end of the groove away from the omnidirectional wheel 3-2.

[0045] like Figure 7 , Figure 8As shown, two mirror-image reconfigurable opening and closing mechanisms 4 are symmetrically mounted on the lower half of the base 1. Each reconfigurable opening and closing mechanism 4 includes: a first opening and closing gear 4-1, a second opening and closing gear 4-2, a crossed roller bearing 9, a servo motor 10, and a swing arm 11. The servo motor 10 is fixedly mounted on the base 1 via a threaded hole pre-drilled at the top of the lower half of the base 1. The movement directions of the servo motors 10 in the two reconfigurable opening and closing mechanisms 4 are always opposite. The first opening and closing gear 4-1 is securely mounted on the servo disc of the servo motor 10. A countersunk hole is formed on the upper surface of the horizontal part of the base 1, and the crossed roller bearing 9 is fixed in the countersunk hole of the base 1 through the countersunk hole of its outer ring. A countersunk hole is formed on the lower surface of the rocker arm 11 at the corresponding position of the crossed roller bearing 9 for installation, and a through hole is formed at the corresponding position of the inner ring of the crossed roller bearing 9. The second opening and closing gear 4-2 is close to the upper surface of the rocker arm 11 and is fastened to the threaded hole of the inner ring of the crossed roller bearing 9 through the through hole of the rocker arm 11. The second opening and closing gear 4-2 meshes with the first opening and closing gear 4-1. When the servo motor 10 of the reconfigurable opening and closing mechanism 4 rotates, it drives the first opening and closing gear 4-1 to rotate, and transmits torque to the second opening and closing gear 4-2 through meshing. Since the second opening and closing gear 4-2 is fastened to the rocker arm 11, it drives the rocker arm 11 to rotate around the rotation direction of the crossed roller bearing 9. A two-section stepped shaft is fixedly connected to the middle of the swing arm 11, and the stepped shaft does not interfere with the second opening gear 4-2. The diameter of the section of the stepped shaft closest to the swing arm 11 (i.e., the lower section) is larger than that of the other section (i.e., the upper section), and the height is the same as that of the second opening gear 4-2. A countersunk hole adapted to the size of the crossed roller bearing 9 is formed on the upper surface of the end of the swing arm 11 away from the servo motor 10.

[0046] like Figure 9As shown, two mirror-image finger alignment mechanisms 5 are symmetrically mounted on the upper half of the base 1 and the reconfigurable opening / closing mechanism 4. Each finger alignment mechanism 5 includes: a first alignment gear 5-1, a second alignment gear 5-2, a third alignment gear 5-3, a crossed roller bearing 9, and a servo motor 10. The servo motor 10 is fixedly mounted on the base 1 via a threaded hole pre-drilled at the top of the upper half of the base 1. The movement directions of the servo motors 10 in the two finger alignment mechanisms 5 are always opposite (it should be noted that the multi-functional grasping robot based on the Mecanum wheel has four servo motors; the servo motors 10 in the two finger alignment mechanisms 5 and the servo motors 10 in the two reconfigurable opening / closing mechanisms 4 are of the same specifications, but they are not shared). The first alignment gear 5-1 is fastened to the servo disk of the servo motor 10, and the first alignment gear 5-1 is located directly above the second opening / closing gear 4-2. The second centering gear 5-2 is mounted on the upper section of the stepped shaft of the swing arm 11, and meshes with the first centering gear 5-1. A rolling bearing 7 and a shim 12 are provided between the second centering gear 5-2 and the stepped shaft. The rolling bearing 7 is used to reduce rotational friction, and the shim 12 is used to prevent the rolling bearing 7 from disengaging from the stepped shaft. The crossed roller bearing 9 is fixed to the countersunk hole on the upper surface of the swing arm 11 through its outer ring countersunk hole. The third centering gear 5-3 is fixed to the crossed roller bearing 9 and meshes with the second centering gear 5-2. When the servo 10 of the finger centering mechanism 5 rotates, it drives the first centering gear 5-1 to rotate, and transmits torque to the second centering gear 5-2 and the third centering gear 5-3 through meshing. When the third centering gear 5-3 is subjected to torque, it rotates around the rotation direction of the crossed roller bearing 9. The upper surface of the third centering gear 5-3 has an integrally designed connector for fixing to the Mecanum wheel finger movement mechanism 2.

[0047] In practical applications, for the reconfigurable opening and closing mechanism 4, when the two servo motors 10 are powered on and receive a signal, the output shaft of the servo motor 10 rotates and resets to the initial position. The servo disk, which is fastened to the output shaft of the servo motor 10, drives the first opening and closing gear 4-1 to rotate. The first opening and closing gear 4-1 meshes with the second opening and closing gear 4-2, which drives the swing arm 11, which is fastened to it, to rotate. The movement directions of the left and right servo motors 10 are always opposite, so that the left and right swing arms 11 can perform symmetrical opening and closing movements.

[0048] For the finger centering mechanism 5, when the two servo motors 10 are powered on and receive a signal, the output shaft of the servo motor 10 rotates and resets to the initial position. The servo disk, which is fastened to the output shaft of the servo motor 10, drives the first centering gear 5-1 to rotate. The first centering gear 5-1 meshes with the second centering gear 5-2. The second centering gear 5-2 plays a reversing role, driving the third centering gear 5-3, which meshes with it, to rotate. This causes the Mecanum wheel moving finger mechanism 2, which is fixed to it, to rotate. The movement directions of the left and right servo motors 10 are always opposite, so that the Mecanum wheel moving finger mechanism 2 can rotate and center symmetrically with the object being grasped, ensuring effective contact with the object being grasped.

[0049] For the Mecanum wheel movement mechanism 2, when the TT motor 2-12 is energized and receives a signal, the output shafts of the four TT motors 2-12 can rotate radially in different directions at different speeds. The TT motor 2-12 whose output shaft is away from the joint shaft 2-14 operates, driving the small synchronous pulley 2-8 on its output shaft to rotate, which in turn drives the third synchronous belt 2-11, which cooperates with the small synchronous pulley 2-8, to move, transmitting torque to the large synchronous pulley 2-7 on the joint shaft 2-14, and then to the joint shaft 2-14. The rotation of the joint shaft 2-14 drives the small synchronous pulley 2-8 on the joint shaft 2-14 to rotate; the small synchronous pulley 2-8 on the joint shaft 2-14 transmits torque through the first synchronous belt 2-9, which cooperates with it, to the large synchronous pulley 2-7 corresponding to the left-hand Mecanum wheel 2-5, further driving the left-hand Mecanum wheel 2-5 to rotate. In this way, the TT motor 2-12 controls the rotation of the top-positioned left-hand Mecanum wheel 2-5, and achieves a reduction ratio of 1:4. The TT motor 2-12, whose output shaft is close to the joint shaft 2-14, runs, driving the gear 2-18 on its output shaft to rotate. The gear 2-18 transmits torque to the shaft gear 2-13 through gear meshing. The small synchronous pulley 2-8, which is fastened to the other end of the shaft gear 2-13, also rotates. Through the second synchronous belt 2-10, the torque is transmitted to the large synchronous pulley 2-7 corresponding to the right-hand Mecanum pulley 2-6, further driving the right-hand Mecanum pulley 2-6 to rotate. This achieves the rotation control of the right-hand Mecanum pulley 2-6 located in the middle by the TT motor 2-12, and also achieves a reduction ratio of 1:4.

[0050] During operation, because the first knuckle of the Mecanum wheel moving finger mechanism 2 has a certain tilt angle in the vertical direction compared to the second knuckle, the left-hand Mecanum wheel 2-5 will contact the object first. After the Mecanum wheel moving finger mechanism 2 receives external force, it will trigger the underactuated structure at the finger joint, namely the small spring 2-17. The small spring 2-17 is stretched (or compressed), and the tilt angle of the first knuckle relative to the second knuckle will decrease until the right-hand Mecanum wheel 2-6 of the second knuckle also contacts the object. After ensuring that each Mecanum wheel effectively releases from the object, by controlling the rotation direction and speed of the four TT motors 2-12, the rotation direction and speed of the left-hand Mecanum wheel 2-5 and the right-hand Mecanum wheel 2-6 are changed. This changes the relative position of the grasped object with respect to the robot hand through effective contact, thus realizing the in-hand operation of the grasped object.

[0051] For the underactuated fixed finger mechanism 3, when the omnidirectional wheel 3-2 is squeezed by the force from inside the robot, due to the length limitation of the groove in the middle section of the omnidirectional wheel fixing plate 3-1, the inner wall will abut against the side of the rolling bearing 8 in the groove, so that the linkage mechanism composed of the first link 3-4, the second link 3-5 and the mirror image of the second link 3-6 cannot continue to change, and the structure remains stationary. At this time, the two identical omnidirectional wheels 3-2 can apply a supporting force to the object inside the robot.

[0052] When the omnidirectional wheel 3-2 is squeezed by a force from outside the robot arm, the inner rolling bearing 8 is confined within the groove. The outer wall of the inner rolling bearing 8 contacts the inner wall of the groove inside the omnidirectional wheel fixing plate 3-1, causing rolling. This opens the linkage mechanism composed of the first link 3-4, the second link 3-5, and the mirror image of the second link 3-6. The greater the external force, the larger the opening angle, and the smaller the distance between the omnidirectional wheel fixing plate 3-1 and the outer surface of the base 1. The entire underactuated fixing finger mechanism 3 is closer to the base 1. When the external force is removed, the large spring 3-7 connecting the first link 3-4, the second link 3-5, and the mirror image of the second link 3-6 rebounds and contracts, causing the linkage mechanism to contract and the underactuated fixing finger mechanism 3 to return to its initial position. The underactuated fixing finger mechanism 3 has a reserved distance to move closer to the base 1, enabling the robot of this invention to be better suited for grasping objects with regular shapes (i.e., objects with arc or flat surfaces) and for inspecting pipes of different specifications.

[0053] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A multi-functional grasping robot based on Mecanum wheels, characterized in that, include: The system comprises a base, a Mecanum wheel moving finger mechanism, an underactuated fixed finger mechanism, a reconfigurable opening and closing mechanism, and a finger centering mechanism. Two mirror-image reconfigurable opening and closing mechanisms are symmetrically mounted on the base and can rotate horizontally. There are two mirror-image finger centering mechanisms, each mounted on the base and the reconfigurable opening and closing mechanisms. Two mirror-image Mecanum wheel moving finger mechanisms are fixedly connected to the rotating structure of the reconfigurable opening and closing mechanism, and the rotating structure can rotate freely around an axis. The underactuated fixed finger mechanism is rotatably connected to the base, and the distance between the fixed finger mechanism and the base is adjustable. The underactuated fixed finger mechanism and the two Mecanum wheel moving finger mechanisms form a triangular configuration. The Mecanum wheel moving finger mechanism includes two finger joints, wherein a left-handed Mecanum wheel is installed on the first finger joint and a right-handed Mecanum wheel is installed on the second finger joint. The first finger joint and the second finger joint are rotatably connected by a joint shaft. The left-handed Mecanum wheel and the right-handed Mecanum wheel are controlled by a motor to control their rotation direction and speed, respectively. The Mecanum wheel moving mechanism includes: a first fixed plate, a second fixed plate, a third fixed plate, a fourth fixed plate, a left-handed Mecanum wheel, a right-handed Mecanum wheel, a large synchronous belt pulley, a small synchronous belt pulley, a first synchronous belt, a second synchronous belt, a third synchronous belt, two TT motors, a shaft gear, a joint shaft, a Mecanum wheel shaft, a small spring, a gear, and a synchronous belt pulley fixing plate; The first knuckle includes: a first fixing plate, a second fixing plate, a left-handed Mecanum wheel, and a Mecanum wheel axle; the first fixing plate and the second fixing plate are mirror images of each other and are installed opposite each other; the left-handed Mecanum wheel is fixedly connected to the Mecanum wheel axle, one end of the Mecanum wheel axle is mounted on the second fixing plate through a rolling bearing, and the other end is provided with a large synchronous pulley, which is mounted on the first fixing plate through a rolling bearing, and the large synchronous pulley is in close contact with the side of the left-handed Mecanum wheel; One end of the joint shaft is mounted on the third fixed plate via a rolling bearing. A small synchronous pulley is fixedly connected to this end. The small synchronous pulley on the joint shaft is connected to the large synchronous pulley corresponding to the left-hand Mecanum pulley via a first synchronous belt. A rolling bearing is fitted and fixedly connected in the middle of the joint shaft. The rolling bearing is embedded in the first fixed plate and the second fixed plate respectively. The other end of the joint shaft passes through the fourth fixed plate and is fixedly connected to one end of the synchronous pulley fixed plate via a rolling bearing. A large synchronous pulley is fixedly connected to this end of the joint shaft. The two ends of the small spring are fixedly connected to two metal optical shafts. The two metal optical shafts are arranged around the joint shaft and parallel to it. The two ends of one metal optical shaft are mounted on the first fixed plate and the second fixed plate via rolling bearings respectively. The two ends of the other metal optical shaft are mounted on the third fixed plate and the fourth fixed plate via rolling bearings respectively. The second joint includes: a third fixed plate, a fourth fixed plate, a right-hand Mecanum wheel, and a Mecanum wheel axle; the third fixed plate and the fourth fixed plate are mirror images of each other and are installed opposite each other; between the third fixed plate and the fourth fixed plate, from top to bottom, are arranged a right-hand Mecanum wheel, a gear with a shaft, and a TT motor; two TT motors are fixedly connected to the third fixed plate, wherein the TT motor whose output shaft is away from the joint shaft has a small synchronous pulley fixedly connected to its output shaft, and the small synchronous pulley is fixedly connected to the other end of the synchronous pulley fixed plate through a rolling bearing; the small synchronous pulley on the output shaft of the TT motor and the large synchronous pulley on the joint shaft are connected by a third synchronous belt, which is located between the fourth fixed plate and the synchronous pulley fixed plate; The TT motor, with its output shaft close to the joint shaft, has a gear fixedly connected to its output shaft. This gear meshes with a belt-driven gear. One end of the belt-driven gear is fixedly connected to a small synchronous pulley and mounted on a third fixed plate via a rolling bearing. The other end of the belt-driven gear is mounted on a fourth fixed plate via a rolling bearing. The right-hand Mecanum wheel is fixedly connected to a Mecanum wheel shaft. One end of the Mecanum wheel shaft is mounted on the fourth fixed plate via a rolling bearing, and the other end is equipped with a large synchronous pulley, which is mounted on the third fixed plate via a rolling bearing. The large synchronous pulley is in close contact with the side of the right-hand Mecanum wheel. The small synchronous pulley on the belt-driven gear and the corresponding large synchronous pulley on the right-hand Mecanum wheel are connected by a second synchronous belt.

2. The multi-functional grasping robot based on Mecanum wheels according to claim 1, characterized in that, The first knuckle containing the left-handed Mecanum wheel is tilted at an angle in the vertical direction compared to the second knuckle containing the right-handed Mecanum wheel.

3. The multi-functional grasping robot based on Mecanum wheels according to claim 1, characterized in that, The underactuated fixing mechanism includes: an omnidirectional wheel fixing plate, an omnidirectional wheel, an omnidirectional wheel axle, a first link, a second link, a mirror image of the second link, and a large spring; there are two omnidirectional wheel fixing plates, which are mirror images of each other and installed opposite each other; two omnidirectional wheel axles are installed between the two omnidirectional wheel fixing plates and can rotate freely; the omnidirectional wheel axles are arranged perpendicularly to the omnidirectional wheel fixing plates and are located at the end away from the connection between the underactuated fixing mechanism and the base; an omnidirectional wheel is sleeved on the omnidirectional wheel axle and can rotate freely on the omnidirectional wheel axle; One end of the first connecting rod is rotatably connected to the base via a rolling bearing, and the other end is a circular boss on which a slotted rolling bearing is mounted. It is installed in a groove in the middle section of the two omnidirectional wheel fixing plates and can roll freely. The second connecting rod and the mirror image of the second connecting rod are mirror images of each other and are installed close to each other. The middle of the second connecting rod and the mirror image of the second connecting rod are both provided with grooves for installing the first connecting rod. When the second connecting rod and the mirror image of the second connecting rod are installed close to each other, the cavity formed by the two grooves is adapted to the width and thickness of the first connecting rod and allows the first connecting rod to rotate freely. The second connecting rod, the first connecting rod, and the mirror image of the second connecting rod are rotatably connected via a metal optical shaft. One end of the second connecting rod and the mirror image of the second connecting rod are rotatably connected to the base via a metal optical shaft. The other end is rotatably connected to the end of the omnidirectional wheel fixing plate near the connection with the base via a metal optical shaft. One end of a large spring is fitted onto the metal optical shaft at this end, and the other end of the large spring is fixed to the circular boss of the first connecting rod. In the initial state, the first connecting rod is located at the end of the groove away from the omnidirectional wheel.

4. The multi-functional grasping robot based on Mecanum wheels according to claim 3, characterized in that, Holes are made at the intersection of the second link, the first link, and the mirror image of the second link, and rolling bearings are installed thereon. The metal optical shaft passes through these three rolling bearings. The cooperation between the rolling bearings and the metal optical shaft realizes the rotational connection of the first link, the second link, and the mirror image of the second link. The rotational connection between the second link and the mirror image of the second link and the base, and the rotational connection between the second link and the mirror image of the second link and the omnidirectional wheel fixing plate are also realized through the cooperation between the rolling bearings and the metal optical shaft.

5. The multi-functional grasping robot based on Mecanum wheels according to claim 1, characterized in that, The reconfigurable opening and closing mechanism includes: a first opening and closing gear, a second opening and closing gear, a crossed roller bearing, a servo motor, and a swing arm; the servo motor is fixedly connected to the base, and the first opening and closing gear is fastened to the servo motor's rudder; a countersunk hole is formed on the upper surface of the horizontal part of the base, and the crossed roller bearing is fixedly connected to the countersunk hole of the base through its outer ring countersunk hole; a countersunk hole is formed on the lower surface of the swing arm at the corresponding position of the crossed roller bearing for installation, and a through hole is formed at the corresponding position of the inner ring of the crossed roller bearing; the second opening and closing gear is close to the upper surface of the swing arm and is fastened to the inner ring threaded hole of the crossed roller bearing through the through hole of the swing arm, and the second opening and closing gear meshes with the first opening and closing gear.

6. The multi-functional grasping robot based on Mecanum wheels according to claim 5, characterized in that, The servos of the two reconfigurable opening and closing mechanisms always move in opposite directions.

7. The multi-functional grasping robot based on Mecanum wheels according to claim 5, characterized in that, The finger centering mechanism includes: a first centering gear, a second centering gear, a third centering gear, a crossed roller bearing, and a servo motor. The servo motor is fixed to the base, and the first centering gear is fastened to the servo motor's rudder. The first centering gear is located directly above the second opening / closing gear. A two-section stepped shaft is fixed to the middle of the swing arm. The stepped shaft does not interfere with the second opening / closing gear. The diameter of the section of the stepped shaft closer to the swing arm is larger than that of the other section, and its height is the same as that of the second opening / closing gear. The second centering gear is installed on the section of the stepped shaft of the swing arm away from the swing arm, and the second centering gear meshes with the first centering gear. The crossed roller bearing is fixed to a countersunk hole on the upper surface of the swing arm through its outer ring countersunk hole. The third centering gear is fixed to the crossed roller bearing and meshes with the second centering gear. The upper surface of the third centering gear has an integrally designed connector for fixed to the Mecanum wheel finger movement mechanism.

8. The multi-functional grasping robot based on Mecanum wheels according to claim 7, characterized in that, The servos of the two finger-aligning mechanisms always move in opposite directions.

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