Universal joint mortise and tenon plate type electronic control memory alloy wire variable stiffness structure

Abstract

A universal joint mortise and tenon plate type electronic control memory alloy wire variable stiffness structure is mainly composed of tenon-shaped plates, the two ends of each tenon-shaped plate are in end-to-end joggling connection to form an integral plate structure, the plates are connected through universal joints, relative rotation between the plates is allowed, the position of a center point is kept unchanged, and the rigidity of the tenon-shaped plates is improved. The smooth bending motion of the two-dimensional structure in the two-degree-of-freedom direction is achieved. The tenon-shaped plates in the structure are connected through the universal joint connecting shafts, the memory alloy wires serve as inhaul cables in the structure, the length and rigidity of the memory alloy wires can be changed after the memory alloy wires are powered on, and therefore the change of the rigidity of the structure is controlled. According to the structure, tree topology can be carried out on the periphery in a joggle joint combination mode so as to meet actual requirements of different projects. The shape and rigidity controllable structure has the advantages of being clear in principle, convenient to assemble, accurate in control, high in unit structure block universality and the like.

Description

Technical Field

[0001] The invention relates to an electrically controlled variable stiffness structure, in particular to a universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure. Background Art

[0002] Shape memory alloy is a new type of smart material that can undergo phase change under the action of stress or temperature, and has a shape memory effect. The shape memory effect means that under certain conditions, the memory alloy material can be deformed, and when certain conditions are met, it can return to its original shape.

[0003] Variable stiffness design is a structural design that allows the structure to change its stiffness while maintaining smooth transmission. In recent years, deformation stiffness design has been a hot topic in the field of mechanical structure research, but most of the variable stiffness structures currently designed have problems such as structural instability, unstable transmission, difficulty in stiffness control, and high processing costs.

[0004] In summary, a universal joint tenon plate type electrically controlled memory alloy wire variable stiffness structure changes the temperature of the memory alloy wire by energizing both ends of the memory alloy wire, thereby changing the length and stiffness of the memory alloy wire. At the same time, the change in resistance of the memory alloy wire is fed back to the host computer through a measuring device. Since the wire length of the memory alloy wire has a fixed functional relationship with the resistance, the strain of the memory alloy wire can be obtained by measuring the resistance change of the memory alloy wire, thereby obtaining the wire length information of the SMA wire, and at the same time, a geometric theoretical model of the wire length and the relative movement between the plates in the module is established. Therefore, the relative displacement and relative deflection angle within and between the modules of the unit can be controlled by adjusting the input current, so that the designed variable stiffness two-dimensional structure is converted into a spatial three-dimensional structure with a controllable shape. Two tenon plates are connected into a single module through a universal joint, and the tenons and tenons at both ends of the single module are mortised to form a variable stiffness two-dimensional structure in a tree-like topology around. The tree-like topology structure can be deformed and locked under the cooperation of the shape changes of each unit module to control the overall shape and structure. The module is simple to manufacture, easy to install, compact in structure and small in weight. In the process of practical application, its stiffness can be selected and the deformation range can be adjusted in a variety of ways, which has great research value and application value.

[0005] Design content

[0006] The purpose of the present invention is to provide a universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure, which is mainly composed of a plurality of mortise plates, and the two ends of the mortise plates are mortised to form a circular overall plate structure. The circular mortise and tenon plate structure schematic diagram is taken as an example in the attached drawings of the specification. The mortise plates in a single module are connected by universal joints, so that the relative position of the center point remains unchanged when the position between the plates changes, so that the two-dimensional plate structure can be smoothly bent in two degrees of freedom, and a certain angle of torsion occurs in the topological structure, which is convenient for control, positioning and measurement. The mortise plate passes through two groups of memory alloy wires with different faces at four corner points centered on the through hole of the universal joint connection shaft, and the two sides are fixed with aluminum tubes. By energizing the memory alloy wire, the memory alloy wire is heated, and the stiffness and length of the memory alloy wire are changed. At the same time, the applied current is different, and the unit length change of the memory alloy wire is also different. The different length changes of the memory alloy wire will cause the two-dimensional structure to have a position offset, and the overall structural shape will change. The tenon-shaped plate can be topologically arbitrarily topologically arranged in four directions during topology, and can be topologically formed into a two-dimensional plate structure of a certain shape. When the input current is controlled, the two-dimensional plate structure of the topology can be changed into a spatial three-dimensional structure of a preset shape.

[0007] The single module part is composed of a tenon plate, a memory alloy wire, a universal joint, a universal joint connecting shaft and a ceramic tube. Two tenon plates are placed symmetrically, and the two plates are connected by a universal joint assembled on the universal joint connecting shaft in the middle. The ceramic insulation tube is built into the tenon plate, and the memory alloy wire passes through the ceramic insulation tube, and is fixed on both sides with aluminum tubes. The ceramic tube has the function of heat insulation and insulation, which prevents the plate body from melting and damaging the body due to the excessive temperature of the memory alloy wire.

[0008] The advantages of the present invention are: by energizing the memory alloy wire, measuring the change in resistance, applying a control current to it, and controlling the change in the shape and stiffness of the plate structure in sections, the shape of the overall topological plate structure changes in an orderly manner. The connection using a universal joint can make the bending movement of the two tenon-shaped plate structures smooth, with a simple structure and high transmission efficiency. The plate body adopts a hollow design to reduce the structural mass, improve the structural sensitivity, and facilitate the heat dissipation of the structure. The shape and stiffness controllable structure has the advantages of clear principles, convenient assembly, simple control, and topological structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the circular mortise and tenon plate structure.

[0010] Figure 2 This is a three-dimensional assembly drawing of a single module structure.

[0011] Figure 3 A schematic cross-section diagram of a single module.

[0012] Figure 4 This is a schematic diagram of the overall assembly of the structure.

[0013] Figure 5 It is a three-dimensional schematic diagram of structural deformation. DETAILED DESCRIPTION

[0014] The present invention is further described below in conjunction with the accompanying drawings

[0015] refer to Figure 1 The present invention discloses a universal joint tenon plate-type electrically controlled memory alloy wire variable stiffness structure. The overall structure is a plate-type two-dimensional structure. By applying a control current to the memory alloy wire, the stiffness and length of the memory alloy wire are controlled to change, thereby achieving the purpose of controlling the shape change of the overall structure. The components thereof are a tenon plate (1), a memory alloy wire (2), a universal joint connecting shaft (3), a universal joint (4) and a ceramic sleeve (5).

[0016] refer to Figure 2 and Figure 3 There are machined grooves at both ends of the tenon-shaped plate for mortise and tenon with other plates, so that the topology is carried out in all directions along the two-dimensional plane through the mortise and tenon of a single module structure; two groups of memory alloy wires on opposite sides of each module are supported by aluminum tubes, connecting the SMA wire power supply and resistance measurement device and the host computer. There are four through holes in the tenon-shaped plate, with a built-in ceramic sleeve, and a hollow structure is used to reduce weight and reduce costs.

[0017] Reference Figure 1 and Figure 4 There are two ways to design the overall structure: one is to provide a group of tenon plates in each row or column of the large overall structure, and connect an SMA wire power supply and resistance measurement device and a host computer at one end of each row or column to control the row or column, so as to achieve the purpose of controlling the shape and stiffness of the entire structure; the other is to control each plate of the small overall structure, and connect an SMA wire power supply and resistance measurement device at both ends to finely control a single module, so that the control of the small overall structure is more precise and the sensitivity is higher.

[0018] Reference Figure 4 and Figure 5 When the device is powered on, the shape of the two-dimensional plate-like structure changes, and a three-dimensional structure with controllable shape deformation occurs.

[0019] The above examples illustrate the structural features of the patent of the present invention, and the purpose is to enable scientific researchers and engineering technicians conducting research in this field to understand the patent of the present invention and to implement the product accordingly.

Claims

1. A universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure, characterized in that: The universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure comprises a mortise-shaped plate (1), a memory alloy wire (2), a universal joint connecting shaft (3), a universal joint (4) and a ceramic sleeve (5).

2. The universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure according to claim 1, characterized in that: The tenon-shaped plate (1) has four through holes on both sides of the center point for installing the memory alloy wire (2), which is clamped and fixed at both ends of the plate by aluminum tubes; based on the shape memory effect of the memory alloy, when the memory alloy wire (2) is energized, the length and resistance of the memory alloy wire (2) change, and by controlling the input current, the wire length contraction amount of the memory alloy wire (2) is controlled, and the variable stiffness structure is driven to rotate or lock, thereby achieving the purpose of controlling the stiffness of the overall plate-type structure.

3. The universal joint mortise and tenon plate type electrically controlled memory alloy wire variable stiffness structure according to claim 1, characterized in that: A through hole is provided at the center point of the outer side of the tenon-shaped plate (1), and a universal joint connecting shaft (3) can be installed at the through hole. The two tenon-shaped plates (1) in the unit module are connected to the two ends of the universal joint (4) by means of the universal joint connecting shaft (3) to form a unit module; the two tenon-shaped plates (1) in the module can rotate relative to each other in two degrees of freedom, and the tenon-shaped plates (1) have tenons and tenon grooves at both ends of the plates, and can be tenoned with other plates to form a complete plate connected end to end; the modules are matched with mortise and tenon structures, so that the unit module can be arbitrarily tree-shaped topology in all directions in a two-dimensional plane.

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