CN107309895B - An underactuated end effector for envelope grabbing and parallel clamping - Google Patents

Abstract

An under-actuated end effector for enveloping and grabbing and parallel clamping relates to an under-actuated end effector and aims to solve the problem that when a traditional under-actuated end effector clamps a target, parallel clamping cannot be guaranteed due to action counterforce of a target object on the effector, and accordingly target grabbing fails; the clamping module comprises two gears and two sets of under-actuated mechanisms; the driving module and the clamping module are arranged on the base; each set of under-actuated mechanism comprises a driving rod, a connecting rod, a clamping finger, an under-actuated finger root, a torsion spring and a finger root; one end of the driving rod is connected with a gear shaft of the gear, the other end of the driving rod is hinged with one end of the connecting rod, the other end of the connecting rod is hinged on the base, one end of the under-actuated finger root is hinged with the clamping finger, the other end of the under-actuated finger root is hinged with one end of the finger root, a torsion spring is arranged between the other end of the under-actuated finger root and the finger root, and the other end of the finger root is. The invention is used for the bionic robot.

Description

Translated fromChinese

一种用于包络抓取和平行夹紧的欠驱动末端执行器An underactuated end effector for envelope grabbing and parallel clamping

技术领域technical field

本发明涉及一种欠驱动执行器，具体涉及一种用于包络抓取和平行夹紧的欠驱动末端执行器。The present invention relates to an underactuated actuator, in particular to an underactuated end effector used for envelope grabbing and parallel clamping.

背景技术Background technique

在仿生机器人领域，欠驱动末端执行器以其驱动数目少、出力大、抓取灵活大特点得到了越来越广泛的应用。传统的欠驱动末端执行器在精确夹紧目标时，由于目标物体给执行器的作用反力，导致欠驱动自由度显现，平行四边形机构被破坏，无法保证平行夹紧，抓取目标容易造成失败。In the field of bionic robots, underactuated end effectors have been more and more widely used because of their small number of drives, large output, and flexible grasping. When the traditional underactuated end effector precisely clamps the target, the underactuated degree of freedom appears due to the reaction force exerted by the target object on the actuator, the parallelogram mechanism is destroyed, parallel clamping cannot be guaranteed, and grasping the target is prone to failure. .

本次发明的目的是改变传统的欠驱动末端执行器的欠驱动关节的位置，从而实现在指尖夹紧目标时，欠驱动关节始终保持刚性，实现平行夹紧的功能；。本次发明的末端执行器包括用于抓取目标的欠驱动执行机构，由微型直流伺服电机、涡轮蜗杆减速器组成的驱动机构以及由弹簧触针组成的连接机构，驱动机构为二指欠驱动机构，左右对称分布，通过减速比为1:1的齿轮对连接传动，保证左右两个手指运动的对称性。微型直流伺服电机中包含有减速比为113:1的行星齿轮减速器，以保证大的输出扭矩；此外，减速比为30:1的涡轮蜗杆减速器在增大转矩的同时，也能够保证机械自锁；连接模块是为了执行器与机械臂的对接，弹簧触针用于电气连接。The purpose of the present invention is to change the position of the underactuated joint of the traditional underactuated end effector, so as to realize that when the fingertip clamps the target, the underactuated joint always maintains rigidity and realizes the function of parallel clamping; The end effector of the present invention includes an underactuated actuator for grasping the target, a drive mechanism composed of a micro DC servo motor, a worm gear reducer, and a connection mechanism composed of a spring contact needle, and the drive mechanism is two-finger underactuated. The mechanism is symmetrically distributed on the left and right, and is connected and driven by a gear pair with a reduction ratio of 1:1 to ensure the symmetry of the movement of the left and right fingers. The miniature DC servo motor contains a planetary gear reducer with a reduction ratio of 113:1 to ensure a large output torque; Mechanical self-locking; the connection module is for the docking of the actuator and the mechanical arm, and the spring contact pin is used for electrical connection.

发明内容SUMMARY OF THE INVENTION

本发明是为解决传统的欠驱动末端执行器在夹紧目标时，由于目标物体给执行器的作用反力，无法保证平行夹紧，造成抓取目标失败的问题，进而提供一种用于包络抓取和平行夹紧的欠驱动末端执行器。The present invention solves the problem of failure to grasp the target due to the fact that the conventional underactuated end effector cannot guarantee the parallel clamping due to the reaction force exerted by the target object on the actuator when clamping the target, and further provides a method for wrapping the target. Underactuated end effector for network gripping and parallel clamping.

本发明为解决上述问题采取的技术方案是：一种用于包络抓取和平行夹紧的欠驱动末端执行器包括基座、对接模块、驱动模块和夹持模块；对接模块安装在基座上，对接模块用于连接机械臂；The technical solution adopted by the present invention to solve the above problems is: an underactuated end effector for enveloping grasping and parallel clamping includes a base, a docking module, a driving module and a clamping module; the docking module is installed on the base , the docking module is used to connect the robotic arm;

夹持模块包括两个齿轮和两套欠驱动机构；驱动模块和夹持模块布置在基座上；每套欠驱动机构包括驱动杆、连杆、连接杆、夹紧指、欠驱动指根、扭簧和指根；驱动模块的输出端连接其中一套欠驱动机构的齿轮，两套欠驱动机构的两个齿轮啮合，驱动杆的一端与齿轮的齿轮轴连接，驱动杆的另一端与连接杆的一端铰接，夹紧指的一端、连接杆的另一端和连杆的一端三者铰接在一起，连杆的另一端铰接在基座上，欠驱动指根的一端与夹紧指铰接，欠驱动指根的另一端与指根的一端铰接且二者之间布置有扭簧，指根的另一端铰接在基座上。The clamping module includes two gears and two sets of under-actuated mechanisms; the driving module and the clamping module are arranged on the base; Torsion spring and finger root; the output end of the drive module is connected to one of the gears of the under-actuated mechanism, the two gears of the two sets of under-actuated mechanisms are meshed, one end of the driving rod is connected with the gear shaft of the gear, and the other end of the driving rod is connected with One end of the rod is hinged, one end of the clamping finger, the other end of the connecting rod and one end of the connecting rod are hinged together, the other end of the connecting rod is hinged on the base, and one end of the underactuated finger is hinged with the clamping finger, The other end of the underactuated finger base is hinged with one end of the finger base with a torsion spring arranged therebetween, and the other end of the finger base is hinged on the base.

本发明与现有技术相比的有益效果是：本发明改变传统的欠驱动末端执行器的欠驱动关节的位置，从而实现在夹紧指夹紧目标时，欠驱动关节始终保持刚性，实现平行夹紧的功能；夹持模块分为驱动杆、连接杆、连杆构成的传动四连杆机构模块，驱动杆作为主动件驱动连杆运动，经过优化后的连杆长度保证了较大的传动角，提高了传动效率；连杆、夹紧指、指根与欠驱动指根构成的刚性体的平行四连杆机构，该平行四连杆机构实现了夹紧指与地面的平行，从而保证了夹紧指始终做平移运动，为平行夹紧提供了条件；指根、欠驱动指根、扭簧构成的欠驱动机构，当夹紧指平行夹紧目标时，产生作用反力，由于指根与欠驱动指根的初始扭转角度保证了欠驱动机构的刚性，平行四边形机构不会被破坏，保证了平行夹紧。通过减速比为1:1的齿轮对连接传动，保证左右两个手指运动的对称性。Compared with the prior art, the present invention has the following beneficial effects: the present invention changes the position of the underactuated joint of the traditional underactuated end effector, so that when the target is clamped by the fingers, the underactuated joint remains rigid and parallelism is achieved. Clamping function; the clamping module is divided into a transmission four-bar linkage module composed of a driving rod, a connecting rod and a connecting rod. The driving rod is used as the active part to drive the movement of the connecting rod. The optimized length of the connecting rod ensures a larger transmission. The parallel four-bar linkage mechanism of the rigid body composed of the connecting rod, the clamping finger, the finger root and the underactuated finger root, the parallel four-bar linkage realizes the parallelism between the clamping finger and the ground, thus ensuring the Therefore, the clamping finger always moves in translation, which provides conditions for parallel clamping; the under-actuated mechanism composed of the finger base, the under-actuated finger base and the torsion spring, when the clamping finger clamps the target in parallel, an acting reaction force is generated. The initial twist angle between the root and the underactuated finger root ensures the rigidity of the underactuated mechanism, the parallelogram mechanism will not be damaged, and parallel clamping is ensured. The transmission is connected by a gear pair with a reduction ratio of 1:1 to ensure the symmetry of the movement of the left and right fingers.

附图说明Description of drawings

图1为本发明的整体结构示意图；Fig. 1 is the overall structure schematic diagram of the present invention;

图2为图1的剖视图；Fig. 2 is the sectional view of Fig. 1;

图3为本发明的爆炸图；Fig. 3 is the exploded view of the present invention;

图4为本发明夹紧指受力分析简图；4 is a schematic diagram of the force analysis of the clamping finger of the present invention;

图5为本发明抓取球状目标示意图。FIG. 5 is a schematic diagram of grasping a spherical target according to the present invention.

具体实施方式Detailed ways

下面结合附图及具体实施方式对本发明的技术方案作进一步地说明。The technical solutions of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

参见图1和图3说明，一种用于包络抓取和平行夹紧的欠驱动末端执行器包括基座15、对接模块14、驱动模块13和夹持模块12；对接模块14安装在基座15上，对接模块14用于连接机械臂；Referring to Figures 1 and 3, an underactuated end effector for enveloping grasping and parallel clamping includes abase 15, adocking module 14, adriving module 13 and aclamping module 12; thedocking module 14 is installed on the base On theseat 15, thedocking module 14 is used to connect the robotic arm;

夹持模块12包括两个齿轮1和两套欠驱动机构；驱动模块13和夹持模块12布置在基座15上；每套欠驱动机构包括驱动杆8、连杆7、连接杆6、夹紧指5、欠驱动指根4、扭簧3和指根2；驱动模块13的输出端连接其中一套欠驱动机构的齿轮1，两套欠驱动机构的两个齿轮1啮合，驱动杆8的一端与齿轮1的齿轮轴连接，驱动杆8的另一端与连接杆6的一端铰接，夹紧指5的一端、连接杆6的另一端和连杆7的一端三者铰接在一起，连杆7的另一端铰接在基座15上，欠驱动指根4的一端与夹紧指5铰接，欠驱动指根4的另一端与指根2的一端铰接且二者之间布置有扭簧3，指根2的另一端铰接在基座15上。Theclamping module 12 includes twogears 1 and two sets of under-actuated mechanisms; thedriving module 13 and theclamping module 12 are arranged on thebase 15; each under-actuated mechanism includes adriving rod 8, aconnecting rod 7, a connectingrod 6, a clamp Thetight finger 5, the underactuatedfinger base 4, thetorsion spring 3 and thefinger base 2; the output end of thedrive module 13 is connected to thegear 1 of one set of underactuated mechanisms, the twogears 1 of the two sets of underactuated mechanisms mesh, and thedrive rod 8 One end of the pin is connected with the gear shaft of thegear 1, the other end of thedriving rod 8 is hinged with one end of the connectingrod 6, one end of the clampingfinger 5, the other end of the connectingrod 6 and one end of the connectingrod 7 are hinged together. The other end of therod 7 is hinged on thebase 15, one end of the underactuatedfinger base 4 is hinged with the clampingfinger 5, the other end of the underactuatedfinger base 4 is hinged with one end of thefinger base 2, and a torsion spring is arranged between the two. 3. The other end of thefinger root 2 is hinged on thebase 15 .

对接模块用于与机械臂末端连接；驱动模块中，电机输出力矩经过涡轮蜗杆减速器减速后，传到夹持模块的驱动杆，为了保持两侧的对称性，夹持模块的齿轮以1:1的减速比传动；驱动杆、基座、连接杆、连杆构成四连杆机构，驱动连杆左右转动；连杆、基座以及指根、扭簧、欠驱动指根构成的刚性体的平行四连杆机构，保证指尖在连杆的驱动下做平移运动，从而为指尖始终垂直抓取目标提供保证；当指尖触及到目标产生作用反力时，由于该欠驱动机构的创新性，能够保证指根与欠驱动指根指尖永远保持刚性，平行四边形机构不会被破坏，从而保证垂直抓取目标。如图5为利用本发明抓取球状目标示意图。The docking module is used to connect with the end of the robotic arm; in the driving module, the output torque of the motor is decelerated by the worm gear reducer, and then transmitted to the driving rod of the clamping module. In order to maintain the symmetry on both sides, the gears of the clamping module are 1:1: 1 reduction ratio transmission; the driving rod, base, connecting rod and connecting rod form a four-bar linkage mechanism, and the driving rod rotates left and right; The parallel four-bar linkage mechanism ensures that the fingertips move in translation under the driving of the connecting rods, thus ensuring that the fingertips always grab the target vertically; It can ensure that the base of the finger and the tip of the underactuated finger base remain rigid forever, and the parallelogram mechanism will not be damaged, thereby ensuring vertical grasping of the target. FIG. 5 is a schematic diagram of grabbing a spherical target using the present invention.

参见图2和图3说明，为了以高驱动的可靠性，采用蜗轮蜗杆减速器为夹持模块12提供动力。驱动模块13包括电机11、蜗杆10和蜗轮9；蜗杆10的一端安装在电机11的输出端上，蜗杆10与蜗轮9啮合，蜗轮9的蜗轮轴上和蜗杆10上各安装有一个齿轮1和一个驱动杆8。如此设置，增大转矩的同时，也能够保证机械自锁。Referring to FIGS. 2 and 3 , for high driving reliability, a worm gear reducer is used to power theclamping module 12 . Thedrive module 13 includes amotor 11, aworm 10 and aworm wheel 9; one end of theworm 10 is mounted on the output end of themotor 11, theworm 10 meshes with theworm wheel 9, and agear 1 and a gear are installed on the worm wheel shaft of theworm wheel 9 and on theworm 10 respectively. Adrive rod 8. In this way, while increasing the torque, it can also ensure the mechanical self-locking.

参见图2说明，为了保证夹持的可靠性，所述夹紧指5为∟形夹紧指，夹紧指5的一个臂的端部、连接杆6的另一端和连杆7的一端三者铰接在一起，欠驱动指根4的一端与夹紧指5的两臂交汇点铰接。如此设置，保证夹紧指在连杆的驱动下做平移运动，从而为夹紧指始终垂直抓取目标提供保证，从而保证垂直抓取目标。Referring to FIG. 2 , in order to ensure the reliability of clamping, the clampingfinger 5 is a ∟-shaped clamping finger, and the end of one arm of the clampingfinger 5 , the other end of the connectingrod 6 and one end of the connectingrod 7 are three They are hinged together, and one end of the underactuatedfinger base 4 is hinged with the junction of the two arms of the clampingfinger 5 . This arrangement ensures that the clamping finger performs translational movement under the driving of the connecting rod, thereby providing a guarantee for the clamping finger to always grasp the target vertically, thereby ensuring that the target is vertically grasped.

优选低，齿轮材质为40Cr。如此使用，强度极限达到700MPa；屈服强度达到500MPa，硬度241-286HBW，精度6级。Preferably low, the gear material is 40Cr. In this way, the strength limit reaches 700MPa; the yield strength reaches 500MPa, the hardness is 241-286HBW, and the precision isgrade 6.

电机11采用微型直流伺服电机，所述微型直流伺服电机包含有减速比为113:1的行星齿轮减速器。保证了较大的输出扭矩；蜗轮9和蜗杆10的减速比为30:1。在增大转矩的同时，也能够保证机械自锁；连接模块是为了执行器与机械臂的对接，弹簧触针用于电气连接。基座15包括上座体15-1和下座体15-2；上座体15-1通过螺栓与下座体15-2可拆卸连接，驱动模块13布置在下座体15-2上，夹持模块12布置在上座体15-1上。如此设置，连接可靠，使用方便。Themotor 11 adopts a micro DC servo motor, and the micro DC servo motor includes a planetary gear reducer with a reduction ratio of 113:1. A large output torque is guaranteed; the reduction ratio of theworm gear 9 and theworm 10 is 30:1. While increasing the torque, it can also ensure mechanical self-locking; the connection module is for the connection between the actuator and the mechanical arm, and the spring contact pin is used for electrical connection. Thebase 15 includes an upper base body 15-1 and a lower base body 15-2; the upper base body 15-1 is detachably connected to the lower base body 15-2 through bolts, and thedrive module 13 is arranged on the lower base body 15-2 to clamp themodule 12 is arranged on the upper base body 15-1. In this way, the connection is reliable and the use is convenient.

对欠驱动机构受力分析如图4所示，箭头表示部件之间相互作用力。夹紧指5向外拉欠驱动指根4，指根2与欠驱动指根4有被拉长的趋势，欠驱动指根4相对于指根2有顺势针旋转的趋势，但由于指根2和欠驱动指根4之间存在机械限位，所以指根2和欠驱动指根4仍然保持刚性，平行四边形结构不会被破坏，指尖仍然相互保持平衡。The force analysis of the underactuated mechanism is shown in Figure 4, and the arrows indicate the interaction force between the components. The clampingfinger 5 pulls the underactuatedfinger base 4 outward, and thefinger base 2 and the underactuatedfinger base 4 tend to be elongated. There is a mechanical limit between 2 and the underactuatedfinger base 4, so thefinger base 2 and the underactuatedfinger base 4 still remain rigid, the parallelogram structure will not be damaged, and the fingertips still maintain balance with each other.

本发明已以较佳实施案例揭示如上，然而并非用以限定本发明，任何熟悉本专业的技术人员，在不脱离本发明技术方案范围内，当可以利用上述揭示的结构及技术内容做出些许的更动或修饰为等同变化的等效实施案例，但是凡是未脱离本发明技术方案的内容，依据本发明的技术实质对以上实施案例所做的任何简单修改、等同变化与修饰，均仍属本发明技术方案范围。The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make use of the structure and technical content disclosed above to make some The modification or modification is equivalent to the equivalent implementation case of the equivalent change, but any simple modification, equivalent change and modification made to the above implementation case according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still belong to The scope of the technical solution of the present invention.

Claims (6)

1. An under-actuated end effector for envelope capture and parallel clamping, comprising: the device comprises a base (15), a butt joint module (14), a driving module (13) and a clamping module (12); the docking module (14) is arranged on the base (15), and the docking module (14) is used for connecting the mechanical arm;

the clamping module (12) comprises two gears (1) and two sets of under-actuated mechanisms; the drive module (13) and the clamping module (12) are arranged on a base (15); each set of under-actuated mechanism comprises a driving rod (8), a connecting rod (7), a connecting rod (6), a clamping finger (5), an under-actuated finger root (4), a torsion spring (3) and a finger root (2); the output end of a driving module (13) is connected with one set of gears (1) of the under-actuated mechanism, two gears (1) of the two sets of under-actuated mechanisms are meshed, one end of a driving rod (8) is connected with a gear shaft of the gears (1), the other end of the driving rod (8) is hinged with one end of a connecting rod (6), one end of a clamping finger (5), the other end of the connecting rod (6) and one end of a connecting rod (7) are hinged together, the other end of the connecting rod (7) is hinged on a base (15), one end of an under-actuated finger root (4) is hinged with the clamping finger (5), the other end of the under-actuated finger root (4) is hinged with one end of a finger root (2), a torsion spring (3) is arranged between the two ends of the finger root (2) and the base (15), and the driving module (13) comprises a motor (11), a worm (; one end of a worm (10) is arranged at the output end of a motor (11), the worm (10) is meshed with a worm wheel (9), and a gear (1) and a driving rod (8) are respectively arranged on a worm wheel shaft of the worm wheel (9) and the worm (10).

2. An under-actuated end effector for envelope capture and parallel clamping according to claim 1, wherein: the clamping finger (5) is a L-shaped clamping finger, the end part of one arm of the clamping finger (5), the other end of the connecting rod (6) and one end of the connecting rod (7) are hinged together, and one end of the underactuated finger root (4) is hinged with the intersection point of the two arms of the clamping finger (5).

3. An under-actuated end effector for envelope capture and parallel clamping according to claim 2, wherein: the material of the gear (1) is 40 Cr.

4. An under-actuated end effector for envelope capture and parallel clamping according to claim 1 or 3, wherein: the motor (11) adopts a miniature direct current servo motor which comprises a planetary gear reducer with the reduction ratio of 113: 1.

5. An under-actuated end effector for envelope capture and parallel clamping according to claim 4, wherein: the reduction ratio of the worm wheel (9) and the worm (10) is 30: 1.

6. An under-actuated end effector for envelope capture and parallel clamping according to claim 1, 3 or 5, wherein: the base (15) comprises an upper base body (15-1) and a lower base body (15-2); the upper seat body (15-1) is detachably connected with the lower seat body (15-2) through bolts, the driving module (13) is arranged on the lower seat body (15-2), and the clamping module (12) is arranged on the upper seat body (15-1).

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