CN-118579278-B - Triangular prism space stretching arm combining Sarrus mechanism and scissor mechanism

CN118579278BCN 118579278 BCN118579278 BCN 118579278BCN-118579278-B

Abstract

The invention discloses a triangular prism space stretching arm combining a Sarrus mechanism and a scissor mechanism, which belongs to the field of aerospace, and the whole stretching arm is formed by longitudinally superposing a plurality of stretching units and has a regular triangular prism structure in a stretching state. The plane scissors elements are combined in a space triangular prism layout and are arranged on three sides of each triangular prism-shaped unfolding unit, so that weak bending resistance of the single plane scissors elements when bearing lateral force is avoided, and the ends of the scissors elements are connected by the sliding rail, so that bending strength of the unfolding arms is improved. Simultaneously, two hinged longitudinal Sarrus connecting rods are respectively added to three edges of the unfolding unit, and after the unfolding unit is completely unfolded, deadlock on the movement of the tail end of the stretching arm is formed by utilizing the characteristic that the transmission angle of the longitudinal Sarrus connecting rods is 0, so that the longitudinal bearing capacity of the whole stretching arm is improved. The stretching arm has the characteristics of high stretching ratio, high longitudinal bearing capacity, relatively simple structure and synchronous stretching.

Inventors

XU KUN
CHEN CHENG
HOU MINGXUAN
LI LONG
DING XILUN

Assignees

北京航空航天大学

Dates

Publication Date: 20260508
Application Date: 20240627

Claims (7)

1. A triangular prism space stretching arm combining a Sarrus mechanism and a scissor mechanism is characterized by comprising a plurality of stretching units, a driving unit, a driving motor and a fixed base which are longitudinally overlapped and connected, wherein the stretching units are right triangular prism-shaped in a stretching state; The three circumferential side surfaces of the unfolding unit are provided with three groups of plane shearing fork mechanisms, and the three circumferential included angles of the top surface are provided with middle connecting pieces, and adjacent connecting pieces are connected through middle sliding rails; Two ends of the bottoms of the three groups of plane scissor mechanisms in the upper unfolding unit are respectively connected with two middle connecting pieces on the same side face in the lower unfolding unit to form a revolute pair; the bottom parts of the three groups of plane scissor mechanisms in the unfolding unit at the lowest layer are respectively connected with three base connecting pieces circumferentially arranged on the top surface of the fixed base to form a revolute pair, and the bottom ends of the three groups of Sarrus connecting rods are respectively connected with the three base connecting pieces to form a revolute pair; The driving unit is provided with a driving screw rod fixedly arranged at the center of the base through threads, the end part of the driving screw rod is coaxially and fixedly connected with the output shaft of the driving motor, and screw nuts on the driving screw rod are connected with three base connecting pieces through three driving rods which are circumferentially and equiangularly arranged.
2. The triangular prism space extension arm combining the Sarrus mechanism and the scissor mechanism as claimed in claim 1, wherein the three sliding rails are respectively embedded and fixed in three grooves formed on the base.
3. The triangular prism space extension arm combining the Sarrus mechanism and the scissor mechanism according to claim 1, wherein the driving screw is coaxially arranged in the central hole of the fixed base and is fixed with the fixed base through a connecting flange sleeved on the driving screw through coaxial threads.
4. The triangular prism space stretching arm combining the Sarrus mechanism and the scissor mechanism according to claim 1, wherein the base connecting piece is a double-revolute pair connecting piece and is provided with a base sliding rail connected with a base, the upper surface of the base is provided with a V-shaped connecting piece formed by a left side plate and a right side plate and a U-shaped connecting piece connected with the base at the inner side of the V-shaped connecting piece, the middle branching line of the included angle of the two side plates of the V-shaped connecting piece is arranged along the sliding direction of a sliding block of a driving unit, is vertically parallel to the U-shaped middle branching line of the cross section of the U-shaped connecting piece and is positioned in a plane vertical to the base, the U-shaped connecting piece is used for connecting a driving screw through a driving rod, and the V-shaped connecting piece is used for connecting a stretching unit through a revolute pair.
5. The triangular prism space extension arm combining the Sarrus mechanism and the scissor mechanism according to claim 1, wherein the middle connecting piece is a double-revolute pair connecting piece, a V-shaped connecting piece formed by a left side plate and a right side plate, a branching intersection point in an included angle of the two side plates is positioned on the axis of the triangular prism, through holes are formed in the upper and lower corresponding positions of the two side plates of the middle connecting piece, and the plane scissor mechanism in an unfolding unit of the upper layer and the lower layer is connected through a revolute pair respectively.
6. The triangular prism space extension arm combining the Sarrus mechanism and the scissor mechanism is characterized in that the middle sliding rail consists of an outer sliding rail and an inner sliding rail, the bottoms of the two sliding rails are connecting plates, the upper parts of the two sliding rails are U-shaped section tracks, the tracks of the outer sliding rail are embedded in the tracks of the inner sliding rail and are connected in a sliding fit mode, one end of the connecting plate of the outer sliding rail is fixedly connected with one middle connecting piece, and a boss is designed at the opposite end of the connecting plate of the inner sliding rail and is fixedly connected with the other middle connecting piece.
7. The triangular prism space extension arm combining the Sarrus mechanism and the scissor mechanism as claimed in claim 1, wherein the unfolding process is as follows: The driving motor drives the driving screw rod to rotate, the screw rod nut ascends relative to the fixed base, the driving rod drives the three base connecting pieces to move towards the center direction of the fixed base, so that the three groups of scissor mechanisms of the lowest-level unfolding unit hinged with the base connecting pieces are driven to fold, the whole unfolding unit longitudinally stretches, the upper plane of the triangular prism ascends, along with the ascending of the upper surface of the triangular prism, the included angles of the three groups of Sarrus connecting rods gradually become larger, the top ends of the three groups of scissor mechanisms simultaneously drive the three groups of scissor mechanisms of the upper level to synchronously fold, the three groups of Sarrus connecting rods synchronously stretch, and the like, the folding movement of the three groups of scissor mechanisms in the lower level unfolding unit can be used as the driving of folding of the three groups of scissor mechanisms in the upper level unfolding unit, finally, when the included angles of all Sarrus connecting rods are 180 degrees, the stretching arms stretch to the maximum length, the stretching action is completed, the horizontal distance between adjacent middle connecting pieces in the unfolding unit is shortened, and the middle sliding rail between the two units is contracted.

Description

Triangular prism space stretching arm combining Sarrus mechanism and scissor mechanism Technical Field The invention relates to a space expanding and contracting mechanism in the field of aerospace, in particular to a triangular prism space expanding arm combining a Sarrus mechanism and a scissor mechanism. Background The space-deployable mechanism generally refers to a mechanism in which each component is deployed step by step from an original closed state in an operating state, and a designated tool is supported to a designated position or stretched to a specific position by the rest of the mechanism, and is a key device in the field of space exploration. Space boom has been used in large numbers as an important component of space retractable mechanisms in space robotic arms, solar panels, and deployable antennas. Therefore, the method has wide application prospect in the fields of space platforms, space detection equipment, various scientific research test satellites and the like. In the background that people pay more attention to space exploration activities, space exploration activities are increasing year by year, demands for extending arms are increasing, and use requirements for the extending arms are also increasing. This type of mechanism is often required to have a high spread-out ratio to save space inside the spacecraft, thereby facilitating the carrying of more payloads and scientific instrumentation. Meanwhile, the high-reliability high-rigidity high-strength bending-resistant load-bearing device is required to have high reliability and high rigidity strength and bending resistance so as to ensure the normal operation of the load-bearing device. As more large equipment enters the space, this means that the extension arm is exposed to greater load loading and longer deployment distances. This presents further challenges for the turnup ratio and strength index of the new extension arm. Existing deployable institution solutions face the risk of instability and even breakage under these challenges, such risks being serious threatens to the proper performance of aerospace tasks. Disclosure of Invention Aiming at the problem that the longitudinal load of the existing extending arm formed by a plurality of scissor units is borne by the scissor rods after the extending arm is fully unfolded, larger force can be generated at the hinging position, and the longitudinal bearing capacity of the mechanism is weaker, the invention provides a triangular prism space extending arm combining a Sarrus mechanism and the scissor mechanism, which is a novel space one-dimensional extending arm designed by combining the scissor units based on space triangular prism layout and the Sarrus mechanism. For each triangular prism shearing unit, a Sarrus mechanism with virtual constraint is added to the edges of the three triangular prisms to improve the longitudinal bearing capacity of the shearing mechanism. The expansion arm mechanism is formed by longitudinally stacking the scissor units incorporating the Sarrus mechanism in one dimension. The stretching arm has the characteristics of high stretching ratio, high longitudinal bearing capacity, relatively simple structure and synchronous stretching. The triangular prism space stretching arm combining the Sarrus mechanism and the scissor mechanism consists of a plurality of stretching units, a driving unit, a driving motor and a fixed base which are longitudinally overlapped and connected, wherein the stretching units are right triangular prism-shaped in a stretching state. Three groups of plane shearing fork mechanisms are arranged on three side surfaces in the circumferential direction of the unfolding unit, meanwhile, middle connecting pieces are arranged at three included angles in the circumferential direction of the top surface, and adjacent connecting pieces are connected through middle sliding rails. The two ends of the top of each plane shearing fork mechanism are respectively connected with two middle connecting pieces positioned on the same side face to form a revolute pair. The three prisms in the circumferential direction of the unfolding unit are provided with three groups of Sarrus connecting rods, and the top ends of the three groups of Sarrus connecting rods are respectively hinged with the three middle connecting pieces to form a revolute pair. Two ends of the bottom of the three groups of plane scissor mechanisms in the upper unfolding unit are respectively connected with two middle connecting pieces on the same side face in the lower unfolding unit to form a revolute pair. The bottoms of the three groups of plane scissor mechanisms in the unfolding unit at the lowest layer are respectively connected with three base connecting pieces circumferentially arranged on the top surface of the fixed base to form a revolute pair. The bottom ends of the three groups of Sarrus connecting rods are respectively connected with three base connecting pieces to form a re