CN106226012A - A kind of device testing parallel institution tension and compression rigidity - Google Patents

Abstract

The invention discloses a device for testing the tensile and compressive stiffness of a parallel mechanism, which comprises a loading device frame body, a disc spring loaded component, a tension and pressure sensor, a force loading rod and a pull rope displacement sensor. The bottom of the pull rope displacement sensor is fixedly connected to the bracket fixed on the ground, the pull rope end of the pull rope displacement sensor is fixedly connected to the top connecting piece of the moving platform of the parallel mechanism to be tested, and one end of the force loading rod is fixed to the top connecting piece of the moving platform of the parallel mechanism. Connected, the other end of the force loading rod is connected with the tension and pressure sensor, one end of the butterfly spring loaded component is connected with the loading device frame, and the other end is connected with the tension and pressure sensor, and the loading device frame is fixed on the support arranged on the ground. The invention solves the problems in the prior art that output compound force/moment, cannot apply linearly independent independent load in a certain direction, and cannot realize continuous change and graded change of loaded load.

Description

A device for testing tension and compression stiffness of parallel mechanism

technical field

The invention relates to the field of stiffness testing, in particular to a device for testing the tension-compression stiffness of a parallel mechanism.

Background technique

Compared with the series mechanism, the parallel mechanism has the characteristics of large rigidity, stable structure, strong bearing capacity, high precision, small motion inertia, and strong real-time controllability. Parallel mechanisms are widely used in various industrial production and practical activities, such as aerospace, precision manufacturing, automobile processing and assembly, health care and many other aspects. To master the performance of parallel mechanism, it is necessary to analyze the mechanical characteristics of the mechanism in depth, and the stiffness of parallel mechanism is an important index of the mechanical characteristics of the mechanism.

Patent No. 200510050822.1 discloses a parallel six-dimensional force sensor calibration device. Patent No. 200510050834.4 discloses a stepless lifting six-dimensional force sensor calibration device. The angle between the rope and the horizontal plane is continuously obtained, and a large reduction ratio reducer is used to apply a load to the six-dimensional force sensor. The disadvantages of both are: the rope pulley mechanism is prone to directional error when applying the load, the rope can only output tension in one direction, and cannot output pressure in the opposite direction; output compound force/torque, and cannot realize independent load loading in one direction.

Chinese patent CN101936797A discloses a six-dimensional force sensor calibration device and its calibration method. The six-dimensional force sensor is loaded by replacing weights with different weights. Loading the weights cannot achieve continuous changes in the loading load. This device can only Apply compound forces/torques.

Chinese patent CN103604561A discloses a six-dimensional force/torque sensor calibration device and its calibration method. Pulleys, wire ropes, and weights are used to load, and a turntable is designed to calibrate the sensor in multiple directions. The disadvantage is that weight loading cannot realize continuous change of loading load.

The common disadvantage of the above patents is that a corresponding workbench needs to be designed, and the cost of calibration for a large-sized six-dimensional force sensor is relatively high.

Contents of the invention

The purpose of the present invention is to provide a device for testing the torsional stiffness of a parallel mechanism, which solves the problem of outputting compound force/moment in the prior art, and cannot apply a linearly independent independent load in a certain direction; loading with weights cannot realize the problem of loading Continuous change, graded change, etc.

The technical solution to realize the object of the present invention is: a device for testing the tension-compression stiffness of a parallel mechanism, including a loading device frame, a butterfly spring loaded assembly, a tension pressure sensor, a force loading rod and a stay rope displacement sensor; The bottom of the rope displacement sensor is fixedly connected to the bracket fixed on the ground, the rope end of the pull rope displacement sensor is fixedly connected to the connecting piece on the top of the moving platform of the parallel mechanism to be tested, and the end of the force loading rod is connected to the connecting piece on the top of the moving platform of the parallel mechanism Fixed connection, the other end of the force loading rod is connected to the tension and pressure sensor, one end of the butterfly spring loaded component is connected to the loading device frame, and the other end is connected to the tension and pressure sensor, and the loading device frame is fixed on the support set on the ground. The belleville spring loaded assembly, the tension pressure sensor, the force loading rod and the stay rope of the stay rope displacement sensor are coaxial.

The frame of the loading device is a cube, wherein any two parallel sides have no side plates, and the four corners of the sides without side plates are welded with triangular connecting plates to increase the overall rigidity of the frame of the loading device, and the frame of the loading device There are a number of installation holes all around.

The butterfly spring loaded assembly includes a loading screw, a copper nut hole plate, a butterfly spring locking cover, a butterfly spring mounting shell, a copper loading cylinder, a pin, a hand wheel, a copper sleeve flange, a first butterfly The outer wall of the side plate on the same side as the loading device frame and the tension pressure sensor is fixedly connected to the copper nut hole plate, and the two guide rods pass through the copper nut hole plate respectively. And the frame of the loading device, one end of the butterfly spring installation shell is fixedly connected with a butterfly spring locking cover, the butterfly spring locking cover is fixed on the guide rod outside the loading device frame, slides with the guide rod, and the butterfly spring is installed The first butterfly spring group, the copper loading cylinder and the second butterfly spring group are arranged in sequence in the housing, wherein the first butterfly spring group is close to the butterfly spring locking cover, and one end of the loading screw passes through the copper nut hole plate in turn Central through hole, loading device frame, butterfly spring locking cover, first butterfly spring group and copper loading cylinder, copper loading cylinder resists the second butterfly spring group, the other end of the loading screw passes through and is equipped with The side wall of the loading device frame parallel to the copper nut hole plate, the end is provided with a hand wheel, and the connection between the other end and the inner side of the side wall is provided with a copper sleeve flange; the copper loading cylinder and the loading screw pass through the pin Solid connection.

The central through hole of the copper nut hole plate is a threaded hole, and the middle section of the corresponding loading screw is provided with threads.

Compared with the prior art, the present invention has significant advantages in that:

(1) The structure of the device is simple and compact, and the manufacturing cost is low.

(2) There are several installation holes around the frame of the loading device, which is convenient for adjusting the installation height and loading direction of the whole device, so as to adapt to parallel mechanisms of various sizes and shapes, and has strong versatility.

(3) The belleville spring group is deformed under load to provide the displacement required for thread feed. Since the load changes linearly with the thread feed, the linear change of load can be controlled by turning the hand wheel. During the rotation of the handwheel, combined with tension and pressure sensors, the load can be controlled continuously and step by step to ensure the accuracy of the applied load.

(4) The load can be output both in forward and reverse rotation of the hand wheel, and it can output both tension and pressure. The process of loading and unloading can be conveniently completed through the forward and reverse rotation of the hand wheel, with simple operation and reliable performance.

(5) Independent loads that are linearly independent along a certain direction can be output.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of the device for measuring the tension-compression stiffness of a parallel mechanism according to the present invention.

Fig. 2 is a front view of the device for measuring the tension-compression stiffness of a parallel mechanism according to the present invention.

Fig. 3 is a partial cross-sectional view of the device for measuring the tension-compression stiffness of a parallel mechanism according to the present invention.

detailed description

The invention will be further described below in conjunction with the accompanying drawings.

1 to 3 , a device for testing the tension-compression stiffness of a parallel mechanism includes a loading device frame 1 , a butterfly spring loaded assembly 2 , a tension-pressure sensor 3 , a force loading rod 4 and a rope displacement sensor 6 . Wherein, the bottom of the stay rope displacement sensor 6 is fixedly connected with the bracket fixed on the ground by screws, the stay rope end of the stay rope displacement sensor 6 is fixedly connected with the connector at the top of the moving platform of the parallel mechanism 5 to be measured, and one end of the force loading rod 4 is connected with The connecting piece on the top of the parallel mechanism 5 moving platform is fixedly connected, the other end of the force loading rod 4 is connected with the tension pressure sensor 3 through a thread, one end of the butterfly spring loaded component 2 is connected with the loading device frame 1, and the other end is connected with the loading device frame 1 through a flange plate. The tension and pressure sensors 3 are connected, and the loading device frame body 1 is fixed on the support arranged on the ground; the butterfly spring loaded component 2, the tension pressure sensor 3, the force loading rod 4 and the stay rope of the stay rope displacement sensor 6 are coaxial .

The loading device frame body 1 has six planes in total, two of which are parallel without side plates, and the remaining four sides are welded into a cube, and triangular connecting plates are welded on the four corners of the faces without side plates, increasing The overall rigidity of the loading device frame 1 is provided with several mounting holes around the loading device frame 1, which is convenient for adjusting the installation height and loading direction of the entire measuring device, so as to adapt to parallel mechanisms of various sizes and shapes.

The butterfly spring loaded assembly 2 includes a loading screw 2-1, a copper nut hole plate 2-3, a butterfly spring locking cover 2-4, a butterfly spring mounting shell 2-5, and a copper loading cylinder 2 -6, pin 2-7, hand wheel 2-9, copper sleeve flange 2-10, the first butterfly spring group 2-8, the second butterfly spring group 2-11 and two guide rods 2-2. The outer wall of the side plate on the same side of the loading device frame body 1 and the tension pressure sensor 3 is fixedly connected to the copper nut hole plate 2-3 by bolts, and the center of the copper nut hole plate 2-3 is provided with a threaded through hole, with the threaded through hole as the Two guide holes are symmetrically distributed in the center, two guide rods 2-2 pass through the guide holes of the copper nut hole plate 2-3 and the side wall of the loading device frame 1 respectively, and one end of the butterfly spring installation shell 2-5 passes through The butterfly spring locking cover 2-4 is threadedly connected, and the rotation is fixed by the set screw, and the butterfly spring locking cover 2-4 is fixed on the guide rod 2-2 on the outside of the loading device frame body 1 by threads. The guide rod 2-2 slides, and the first butterfly spring group 2-8, the copper loading cylinder 2-6 and the second butterfly spring group 2-11 are arranged successively in the butterfly spring installation housing 2-5, wherein the first The butterfly spring group 2-8 is close to the butterfly spring locking cover 2-4, one end of the loading screw 2-1 passes through the center through hole of the copper nut hole plate 2-3, the loading device frame 1, and the butterfly spring lock Tight cover 2-4, first butterfly spring group 2-8 and copper loading cylinder 2-6, copper loading cylinder 2-6 against the second butterfly spring group 2-11, the other end of loading screw rod 2-1 Pass through the side wall of the loading device frame 1 parallel to the copper nut hole plate 2-3, the end is provided with a hand wheel 2-9, and the other end is provided with a copper sleeve at the connection with the inner side of the side wall Flange 2-10; copper loading cylinder 2-6 and loading screw rod 2-1 are fixedly connected by pin 2-7, so that the load acts on two butterfly spring groups through copper loading cylinder 2-6.

Loading screw 2-1 is because the total deformation of the butterfly spring group is not large during the loading process, so loading screw 2-1 only needs to process a section of thread near the central threaded hole of copper nut hole plate 2-3, and the rest are polished rods. The loading screw 2-1 moves in the threaded hole of the copper nut hole plate 2-3, and the thread feed reduction ratio is large, so that the force of the hand wheel 2-9 is reduced and a larger load is output.

The guide rod 2-2 limits the rotation of the Belleville spring loaded assembly 2 as a whole around the axis of the loading screw 2-1, retaining the movement of the Belleville spring loaded assembly 2 as a whole along the axis of the loading screw 2-1, ensuring that the loaded load remains It can be transmitted along the axial direction of the loading screw 2-1. The deformation of the two butterfly spring groups under load provides the displacement required for thread feed and the required rotation of the handwheel 2-9. The handwheel 2-9 can output load in both forward and reverse rotations. The copper loading cylinder 2-6 Compression is applied by compressing the first Belleville spring set 2-8, and tension is applied by compressing the second Belleville spring set 2-11.

The tension pressure sensor 3 is the GLBLY wheel spoke tension pressure sensor produced by Shanghai Gaoling Sensing System Engineering Co., Ltd., with a threaded hole in the center and several connection holes around it. The Belleville spring group is deformed under load, and the load changes linearly with the thread feed, so the load changes linearly with the rotation of the handwheel 2-9. Turn the handwheel 2-9 in a certain direction to load, combined with the tension and pressure sensor 3, the load can be controlled continuously and in stages to ensure the accuracy of the applied load, and the unloading can be completed by turning the handwheel 2-9 in the opposite direction, and at the same time Obtain the tension and compression load F.

The force loading rod 4 can be selected with an appropriate length according to the actual use situation, so as to enhance the versatility, and output an independent load along its axial direction. The rope displacement sensor 6 can obtain the displacement change x of the parallel mechanism 5 under the load, then the tensile and compressive stiffness is:

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; x</span>}}$

Fix the fixed platform of the parallel mechanism 5 to the ground, set the test device according to the required test direction, turn the hand wheel 2-9 to load, and combine the tension and pressure sensor 3 to control the loading load to change step by step, that is, the output load is from zero to full scale Divided into 10 to 12 loads. After the loading is completed, the hand wheel 2-9 is reversed to complete the unloading, and the same control output load is divided into 10-12 loadings from full scale to zero. In order to ensure the measurement accuracy, the loading and unloading process was repeated several times. During the loading process, the displacement change of the parallel mechanism 5 under the load is obtained in real time through the rope displacement sensor 6, and the tensile and compressive stiffness K _F of the parallel mechanism 5 in this direction is analyzed in combination with the data.

Claims (4)

1. A device for testing the tension-compression stiffness of a parallel mechanism, characterized in that: it comprises a loading device frame (1), a Belleville spring loaded assembly (2), a tension-pressure sensor (3), a force loading rod (4) and The stay rope displacement sensor (6); wherein, the bottom of the stay rope displacement sensor (6) is fixedly connected with the support fixed on the ground, and the stay rope end of the stay rope displacement sensor (6) is connected to the moving platform of the parallel mechanism (5) to be measured The top connector is fixedly connected, one end of the force loading rod (4) is fixedly connected with the connector on the top of the moving platform of the parallel mechanism (5), the other end of the force loading rod (4) is connected with the tension pressure sensor (3), and the butterfly spring is One end of the loading assembly (2) is connected to the loading device frame (1), and the other end is connected to the tension pressure sensor (3), and the loading device frame (1) is fixed on a support arranged on the ground; the butterfly spring loaded assembly ( 2), the four coaxial lines of the stay rope of the pull pressure sensor (3), the force loading rod (4) and the stay rope displacement sensor (6). 2. The device for testing the tension-compression stiffness of a parallel mechanism according to claim 1, characterized in that: the loading device frame (1) is a cube, wherein any two parallel sides have no side plates, and the no side plates Weld triangular connection plates on the four corners of the side of the frame to increase the overall rigidity of the loading device frame (1), and several mounting holes are provided around the loading device frame (1). 3. The device for testing the tension-compression stiffness of a parallel mechanism according to claim 2, characterized in that: the Belleville spring loaded assembly (2) includes a loading screw (2-1), a copper nut hole plate (2- 3), butterfly spring locking cover (2-4), butterfly spring installation shell (2-5), copper loading cylinder (2-6), pin (2-7), hand wheel (2-9 ), copper sleeve flange (2-10), first butterfly spring group (2-8), second butterfly spring group (2-11) and two guide rods (2-2), loading device frame (1) The outer wall of the side plate on the same side as the tensile pressure sensor (3) is fixedly connected to the copper nut hole plate (2-3), and the two guide rods (2-2) respectively pass through the copper nut hole plate (2-3 ) and the loading device frame (1), one end of the butterfly spring installation shell (2-5) is fixedly connected with a butterfly spring locking cover (2-4), and the butterfly spring locking cover (2-4) is fixed on On the guide rod (2-2) on the outside of the loading device frame (1), slide along with the guide rod (2-2), and the first disc spring group (2 -8), copper loading cylinder (2-6) and the second butterfly spring group (2-11), wherein the first butterfly spring group (2-8) is close to the butterfly spring locking cover (2-4 ), one end of the loading screw (2-1) passes through the center through hole of the copper nut hole plate (2-3), the loading device frame (1), the butterfly spring locking cover (2-4), the first butterfly shaped spring group (2-8) and copper loading cylinder (2-6), copper loading cylinder (2-6) is against the second belleville spring group (2-11), and loading screw rod (2-1) is another One end passes through the side wall of the loading device frame (1) parallel to the copper nut hole plate (2-3), the end is provided with a hand wheel (2-9), and the other end is connected to the inner side of the side wall A copper sleeve flange (2-10) is provided at the joint; the copper loading cylinder (2-6) and the loading screw (2-1) are fixedly connected by pins (2-7). 4. The device for testing the tension-compression stiffness of a parallel mechanism according to claim 3, characterized in that: the central through hole of the copper nut hole plate (2-3) is a threaded hole, and the corresponding loading screw (2-1) The middle section is provided with threads.