Space deployable mechanism comprising symmetrical seven-rod unit and auxetic surface structure

Abstract

The invention discloses a space extensible mechanism comprising a symmetrical seven-rod unit and an auxetic surface structure, and belongs to the technical field of mechanism application. Comprising a rack, a driving connecting rod, a side link, a I-type side link, a II-type connecting rod, an auxiliary connecting rod, a sliding block, a cross-shaped connecting rod, a III-type connecting rod, a IV-type connecting rod, a V-type connecting rod, a VI-type connecting rod, a I-type auxetic structure, a II-type auxetic structure, a III-type auxetic structure and a IV-type auxetic structure. The mechanism is driven through the driving connecting rod, the pulling and expanding structure is carried on the surface of the extensible mechanism composed of the symmetrical seven-rod closed loop, the grabbing capacity of the mechanism for small targets when the mechanism executes a grabbing task is effectively improved, torque is transmitted through the auxiliary connecting rod, and the grabbing efficiency is improved. The whole mechanism has the advantages of being single in freedom degree, convenient to control, good in rigidity, continuous and stable in movement and the like, and has wide application prospects in the fields of space / deep sea exploration, tail end grabbing and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanism application, and in particular relates to a spatially expandable mechanism including a symmetrical seven-bar unit and a tensile expansion surface structure. Background Art

[0002] The spatially expandable mechanism has the property of folding and expanding from a folded state to a predetermined configuration, and has the advantages of high rigidity, high reliability, and high stability. Among them, all components in the single closed-loop mechanism form a closed loop through kinematic pairs, the relative movement between the components is strictly constrained, and the degree of freedom of the system is low. At the same time, since the movement of the components in the single closed-loop mechanism is enclosed in a loop, the motion transmission is more accurate and can effectively reduce errors. This is very consistent with the requirements of the grasping task. Therefore, in the design and development of the grasping mechanism, the spatially expandable mechanism constructed by the single closed-loop mechanism is widely used. However, there are gaps between the connecting rods of the spatially expandable mechanism constructed by the single closed loop. When grasping small targets, the target will slip through the connecting rods of most existing mechanisms, making it impossible to complete the grasping task. Therefore, combined with the advantages of the single closed-loop expandable mechanism, a new technical solution is urgently needed in the existing technology to solve this problem. Summary of the invention

[0003] The technical problem to be solved by the present invention is: to propose a spatial expandable mechanism composed of a seven-rod single closed loop, and to install a tensile surface structure on the inner surface of the mechanism, which can deform with the deformation of the expandable mechanism and always cover the inner surface of the expandable mechanism to protect the grasping target.

[0004] The technical solution provided by the present invention is: A single-degree-of-freedom expandable mechanism consisting of a single-degree-of-freedom symmetrical seven-bar closed-loop unit and a tensile expansion surface structure, comprising: a frame, a driving connecting rod, a connecting rod, a type I connecting rod, a type II connecting rod, an auxiliary connecting rod, a slider, a cross connecting rod, a type III connecting rod, a type IV connecting rod, a type V connecting rod, a type VI connecting rod, a type I tensile expansion structure, a type II tensile expansion structure, a type III tensile expansion structure and a type IV tensile expansion structure; The frame is provided with a center hole, the frame and the driving connecting rod are hingedly connected at the center hole, and the geometric center of the revolving pair coincides with the center of the center hole. The frame has four branch rods, and the angle between two adjacent branches is 90 degrees, wherein each branch rod is hingedly connected to the connecting rod; The driving connecting rod is hingedly connected to the frame at the center hole. In addition, the driving connecting rod is provided with four branch rods, and the angle between two adjacent branch rods is 90 degrees, wherein each branch rod is hingedly connected to the type I connecting rod; There are four connecting rods, one end of which is hingedly connected to the frame branch rod through a rotating pair, and the other end is hingedly connected to the type III connecting rod through a rotating pair, and the axis angle of the rotating pairs at both ends is 45 degrees; There are eight type I connecting rods, and the included angle between the rotational sub-axes at both ends is 45 degrees. Every two type I connecting rods form a group. In each group structure, one end of a type I connecting rod is hingedly connected to the branch rod of the driving connecting rod through a rotational sub-axle, and the other end is hingedly connected to the type II connecting rod through a rotational sub-axle; one end of another type I connecting rod is hingedly connected to the type II connecting rod, and the other end is hingedly connected to the type VI connecting rod. The connection methods of the other three groups are the same. There are eight type II connecting rods, each having a central rotating pair and two external rotating pairs, wherein the external rotating pair I is parallel to the central rotating pair, and the axis of the external rotating pair II is perpendicular to the axis of the central rotating pair; the external rotating pair I is hingedly connected to the auxiliary connecting rod, the external rotating pair II is hingedly connected to the type I connecting rod, and the central rotating pair is hingedly connected to the cross connecting rod; There are eight auxiliary connecting rods, the revolving pairs at both ends of the connecting rods are parallel, one end of the auxiliary connecting rods is hingedly connected to the II-type connecting rod, and the other end is hingedly connected to the slider; The slider is provided with four, the revolving pairs at both ends of the slider are parallel, and the axis is perpendicular to the axis of the central cylindrical slideway; the two external revolving pairs are respectively hingedly connected to the two auxiliary connecting rods, and the cylindrical slideway is slidably connected to the cylindrical guide rail of the cross connecting rod; There are four cross connecting rods, and the connecting rod has four branch rods, all of which are revolving pairs at the ends. The angle between the branch rods is 90 degrees, forming a cross shape. A cylindrical guide rail is provided at the center of the cross shape, which is slidably connected to the slider; the four branch rods are divided into two groups, wherein two opposite revolving pairs form one group, and the revolving pairs of the branch rods in the same group are parallel, and the axes of the two revolving pairs and the cylindrical guide rails in different groups are perpendicular to each other, and the two cross revolving pairs I are respectively hingedly connected to the two II-type connecting rods, and the two cross revolving pairs II are respectively hingedly connected to the two III-type connecting rods; There are eight type III connecting rods, the axes of the rotating pairs at both ends are perpendicular to each other, and each group of two is a group, one end of which is hingedly connected to the connecting rod and the other end is hingedly connected to the cross connecting rod; another end is hingedly connected to the type IV connecting rod and the other end is hingedly connected to the cross connecting rod, and the connection methods of the other three groups are the same; There are four type IV connecting rods, the included angle of the rotating secondary axis at both ends is 45 degrees, one end is hingedly connected to the type III connecting rod, and the other end is hingedly connected to the type V connecting rod; There are four V-type connecting rods, the rotation axes of the two ends are perpendicular to each other, one end is hingedly connected to the IV-type connecting rod, and the other end is hingedly connected to the VI-type connecting rod; There are four VI-type connecting rods, the rotation axes of the two ends are perpendicular to each other, one end is hingedly connected to the V-type connecting rod, and the other end is hingedly connected to the I-type connecting rod; There are eight type I tensile expansion structures, two in each group, one of which is fixedly connected to the type V connecting rod and the type VI connecting rod; another is fixedly connected to a branch rod of the frame and a branch rod of the driving connecting rod, and the connection methods of the other three groups are the same; There are four type II tensile expansion structures, which are fixedly connected to the type I connecting rod and the type IV connecting rod; The type III tensile expansion structures are provided in four pieces and are fixedly connected to two type II connecting rods and a group of type III connecting rods; There are four type IV tensile expansion structures, which are fixedly connected to the connecting rod and the type I connecting rod; Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: a spatial expandable mechanism based on a single-degree-of-freedom symmetrical seven-bar closed loop and a tensile expansion surface structure of the present invention is driven by a driving connecting rod, and the tensile expansion structure is mounted on the surface of the expandable mechanism composed of a symmetrical seven-bar closed loop, which effectively improves the grasping ability of the mechanism for small targets when performing grasping tasks, and transmits torque through an auxiliary connecting rod, so that the overall mechanism has the advantages of single degree of freedom, easy control, good rigidity, continuous and smooth movement, etc., and has broad application prospects in the fields of space / deep sea exploration, end grasping, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is a schematic diagram of the fully closed structure of the mechanism of the present invention; Figure 2 It is a schematic diagram of the fully expanded structure of the mechanism of the present invention; Figure 3 It is a schematic diagram of the structure of the type II connecting rod, auxiliary connecting rod, slider and cross connecting rod of the present invention; Figure 4 It is a schematic diagram of the frame and driving connecting rod structure of the present invention; Figure 5 It is a schematic diagram of the type II connecting rod structure of the present invention; In the figure, 1-frame, 2-driving connecting rod, 3-connecting rod, 401-type I connecting rod Ⅰ, 402-type I connecting rod Ⅱ, 5-type II connecting rod, 6-auxiliary connecting rod, 7-slider, 8-cross connecting rod, 901-type III connecting rod Ⅰ, 902-type III connecting rod Ⅱ, 10-type IV connecting rod, 11-type V connecting rod, 12-type VI connecting rod, 1301-type I tensile expansion structure Ⅰ, 1302-type I tensile expansion structure Ⅱ, 14-type II tensile expansion structure, 15-type III tensile expansion structure, 16-type IV tensile expansion structure, 101-frame branch rod, 201-driving connecting rod branch rod. DETAILED DESCRIPTION

[0006] The present invention will be further described below in conjunction with the embodiments: A spatially deployable mechanism with a single-degree-of-freedom symmetrical seven-bar closed loop and a tensile expansion surface structure, such as Figure 1 , Figure 2 , Figure 3 , including a frame 1, a driving connecting rod 2, a connecting rod 3, a type I connecting rod Ⅰ401, a type I connecting rod Ⅱ402, a type II connecting rod 5, an auxiliary connecting rod 6, a slider 7, a cross connecting rod 8, a type III connecting rod Ⅰ901, a type III connecting rod Ⅱ902, a type IV connecting rod 10, a type V connecting rod 11, a type VI connecting rod 12, a type I tensile expansion structure Ⅰ1301, a type I tensile expansion structure Ⅱ1302, a type II tensile expansion structure 14, a type III tensile expansion structure 15, a type IV tensile expansion structure 16, a frame branch rod 101, and a driving connecting rod branch rod 201; The frame 1 is provided with a center hole, and the frame 1 is hingedly connected to the driving connecting rod 2 at the center hole, and the geometric center of the revolving pair coincides with the center of the center hole. The frame 1 has four branch rods, and the angle between two adjacent branch rods 101 is 90 degrees, wherein each branch rod 101 is hingedly connected to the connecting rod 3; The driving connecting rod 2 is hingedly connected to the frame 1 at the center hole. In addition, the driving connecting rod 2 is provided with four branch rods, and the angle between two adjacent branch rods 201 is 90 degrees, wherein each branch rod 201 is hingedly connected to the type I connecting rod I 401; The connecting rods 3 are provided with four, one end of which is hingedly connected to the branch rod of the frame 1 through a rotating pair, and the other end is hingedly connected to the type III connecting rod II 902 through a rotating pair, and the axis angle of the rotating pairs at both ends is 45 degrees; There are four type I connecting rods Ⅰ401, and the included angle between the rotational axes at both ends is 45 degrees. One end is hingedly connected to the branch rod 201 of the driving connecting rod 2 through a rotational pair, and the other end is hingedly connected to the type II connecting rod 5 through a rotational pair. The said type III connecting rod II 902 is provided with four, one end of which is hingedly connected to the connecting rod 2, and the other end of which is hingedly connected to the cross connecting rod 8; There are eight type II connecting rods 5, each having a central rotating pair and two external rotating pairs, wherein the external rotating pair I is parallel to the central rotating pair, and the axis of the external rotating pair II is perpendicular to the axis of the central rotating pair; the external rotating pair I is hingedly connected to the auxiliary connecting rod 6, the external rotating pair II is hingedly connected to the type I connecting rod I401, and the central rotating pair is hingedly connected to the cross connecting rod 8; The auxiliary connecting rods 6 are provided with eight, the revolving pairs at both ends of the connecting rods are parallel, one end of the auxiliary connecting rods 6 is hingedly connected to the II-type connecting rod 5, and the other end is hingedly connected to the slider 7; The slider 7 is provided with four, the revolving pairs at both ends of the slider 7 are parallel, and the axis is perpendicular to the axis of the central cylindrical slideway; the two revolving pairs are respectively hingedly connected to the two auxiliary connecting rods 6, and the cylindrical slideway is slidably connected to the cylindrical guide rail of the cross connecting rod 8; The cross connecting rod 8 is provided with four, and the connecting rod has four branch rods, and the ends are all rotating pairs. The angle between the branch rods is 90 degrees, forming a cross shape. A cylindrical guide rail is provided at the center of the cross, which is slidably connected with the slider 7; the four branch rods can be divided into two groups, wherein two opposite rotating pairs form one group, and the rotating pairs of the branch rods in the same group are parallel, and the axes of the two rotating pairs and the cylindrical guide rails in different groups are perpendicular to each other, and the two cross rotating pairs I are respectively hingedly connected to the two II-type connecting rods 5, and the two cross rotating pairs II are respectively hingedly connected to the III-type connecting rod I901 and the III-type connecting rod II902; The said type III connecting rods Ⅰ901 are provided with four, the axes of the rotating pairs at both ends are perpendicular to each other, one end is hingedly connected to the type IV connecting rod 10, and the other end is hingedly connected to the cross connecting rod 8; There are four type I connecting rods II 402, the included angle of the rotation secondary axis of the two ends of which is 45 degrees, one end is hingedly connected to the type II connecting rod 5, and the other end is hingedly connected to the type VI connecting rod 12; There are four type IV connecting rods 10, with the included angle of the rotating secondary axis at both ends being 45 degrees, one end of which is hingedly connected to the type III connecting rod I901, and the other end of which is hingedly connected to the type V connecting rod 11; There are four V-type connecting rods 11, the rotation axes of the two ends are perpendicular to each other, one end is hingedly connected to the IV-type connecting rod 10, and the other end is hingedly connected to the VI-type connecting rod 12; There are eight type I expansion structures 13, two in each group, wherein the type I expansion structure I 1301 is fixedly connected to a branch rod 101 of the frame 1 and a branch rod 201 of the driving connecting rod 2; the type I expansion structure II 1302 is fixedly connected to the type V connecting rod 11 and the type VI connecting rod 12, and the connection methods of the other three groups are the same; The said type II tensile expansion structure 14 is provided with four, and is fixedly connected with the type I connecting rod II 402 and the type IV connecting rod 10; The said type III tensile expansion structure 15 is provided with four, and is fixedly connected with two type II connecting rods 5, one type III connecting rod I 901, and one type III connecting rod II 902; The IV-type tensile expansion structures 16 are provided in four pieces and are fixedly connected to the connecting rod 3 and the I-type connecting rod I401; The spatially expandable mechanism is a single degree of freedom, and is driven by the rotation of the driving link around the center hole of the frame, thereby switching the folding and unfolding states of the mechanism. The specific process is as follows: the rotation of the driving link 2 is transmitted to the type II link 5 through four type I links I401, so that it rotates around its own central rotation pair, and the type II link 5 is transmitted to the type II link 5 on the opposite side through the auxiliary link 6 and the slider 7, and finally transmitted to the type V link 11 and the type VI link 12 through the type I link II402, completing the unfolding / folding of the mechanism; Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: a spatial expandable mechanism of the present invention with a single-degree-of-freedom symmetrical seven-bar closed loop and a tensile expansion surface structure is driven by a driving connecting rod, and the tensile expansion structure is mounted on the surface of the expandable mechanism, which effectively improves the mechanism's grasping ability for small targets when performing grasping tasks, and transmits torque through an auxiliary connecting rod, so that the overall mechanism has the advantages of single degree of freedom, easy control, good rigidity, continuous and smooth movement, etc., and has broad application prospects in the fields of space / deep sea exploration, end grasping, etc.

Claims

1. A spatially deployable mechanism comprising a symmetrical seven-bar unit and a tensile expansion surface structure, characterized in that: include: Frame, driving connecting rod, connecting rod, type I connecting rod, type II connecting rod, auxiliary connecting rod, slider, cross connecting rod, type III connecting rod, type IV connecting rod, type V connecting rod, type VI connecting rod, type I tensile expansion structure, type II tensile expansion structure, type III tensile expansion structure and type IV tensile expansion structure; The frame is provided with a center hole, the frame and the driving connecting rod are hingedly connected at the center hole, and the geometric center of the revolving pair coincides with the center of the center hole; The driving connecting rod is hingedly connected to the frame at the center hole. In addition, the driving connecting rod is provided with four branch rods, and the angle between two adjacent branch rods is 90 degrees, wherein each branch rod is hingedly connected to the type I connecting rod; There are four connecting rods, one end of which is hingedly connected to the frame branch rod through a rotating pair, and the other end is hingedly connected to the type III connecting rod through a rotating pair, and the axis angle of the rotating pairs at both ends is 45 degrees; There are eight type I connecting rods, and the included angle between the rotational sub-axes at both ends is 45 degrees. Every two type I connecting rods form a group. In each group structure, one end of a type I connecting rod is hingedly connected to the branch rod of the driving connecting rod through a rotational sub-axle, and the other end is hingedly connected to the type II connecting rod through a rotational sub-axle; one end of another type I connecting rod is hingedly connected to the type II connecting rod, and the other end is hingedly connected to the type VI connecting rod. The connection methods of the other three groups are the same. There are eight type II connecting rods, each having a central rotating pair and two external rotating pairs, wherein the external rotating pair I is parallel to the central rotating pair, and the axis of the external rotating pair II is perpendicular to the axis of the central rotating pair; the external rotating pair I is hingedly connected to the auxiliary connecting rod, the external rotating pair II is hingedly connected to the type I connecting rod, and the central rotating pair is hingedly connected to the cross connecting rod; There are eight auxiliary connecting rods, the revolving pairs at both ends of the connecting rods are parallel, one end of the auxiliary connecting rods is hingedly connected to the II-type connecting rod, and the other end is hingedly connected to the slider; The slider is provided with four, the revolving pairs at both ends of the slider are parallel, and the axis is perpendicular to the axis of the central cylindrical slideway; the two external revolving pairs are respectively hingedly connected to the two auxiliary connecting rods, and the cylindrical slideway is slidably connected to the cylindrical guide rail of the cross connecting rod; There are four cross connecting rods, and the connecting rod has four branch rods, all of which are revolving pairs at the ends. The angle between the branch rods is 90 degrees, forming a cross shape. A cylindrical guide rail is provided at the center of the cross shape, which is slidably connected to the slider; the four branch rods are divided into two groups, wherein two opposite revolving pairs form one group, and the revolving pairs of the branch rods in the same group are parallel, and the axes of the two revolving pairs and the cylindrical guide rails in different groups are perpendicular to each other, and the two cross revolving pairs I are respectively hingedly connected to the two II-type connecting rods, and the two cross revolving pairs II are respectively hingedly connected to the two III-type connecting rods; There are eight type III connecting rods, the axes of the rotating pairs at both ends are perpendicular to each other, and two of them form a group. One end of a type III connecting rod in each group is hingedly connected to the connecting rod, and the other end is hingedly connected to the cross connecting rod; one end of another type III connecting rod is hingedly connected to the type IV connecting rod, and the other end is hingedly connected to the cross connecting rod; There are four type IV connecting rods, the included angle of the rotating secondary axis at both ends is 45 degrees, one end is hingedly connected to the type III connecting rod, and the other end is hingedly connected to the type V connecting rod; There are four V-type connecting rods, the rotation axes of the two ends are perpendicular to each other, one end is hingedly connected to the IV-type connecting rod, and the other end is hingedly connected to the VI-type connecting rod; There are four VI-type connecting rods, the rotation axes of the two ends are perpendicular to each other, one end is hingedly connected to the V-type connecting rod, and the other end is hingedly connected to the I-type connecting rod; There are eight type I tensile expansion structures, two of which form a group, one type I tensile expansion structure in each group is fixedly connected to the type V connecting rod and the type VI connecting rod; another type I tensile expansion structure is fixedly connected to a branch rod of the frame and a branch rod of the driving connecting rod; There are four type II tensile expansion structures, which are fixedly connected to the type I connecting rod and the type IV connecting rod; There are four type III tensile expansion structures, which are fixedly connected to two type II connecting rods and a group of type III connecting rods.

2. The spatially expandable mechanism comprising a symmetrical seven-bar unit and a tensile expansion surface structure according to claim 1, characterized in that: There are four type IV tensile expansion structures, which are fixedly connected to the connecting rod and the type I connecting rod; The frame has four branches, and the angle between two adjacent branches is 90 degrees, wherein each branch is hingedly connected to the connecting rod.

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