CN103575446A - Medium-measurement-range three-dimensional force sensor - Google Patents

Abstract

The invention relates to a medium-range three-dimensional force sensor, which includes a loading boss, and a front rectangular beam, a rear rectangular beam, a left rectangular beam and a right rectangular beam, and a left rectangular beam and a right rectangular beam are horizontally arranged on the outer side of the loading boss. Strain gauges are respectively provided on the upper and lower sides close to the loading boss, strain gauges are respectively arranged on the left and right sides of the left and right rectangular beams near the loading boss, and the front rectangular beam and the rear rectangular beam Strain gauges are provided on the upper parts of the left and right sides close to the loading boss; the outer ends of the front rectangular beam, the rear rectangular beam, the left rectangular beam and the right rectangular beam are all connected with fixed bosses. The beneficial effects of the present invention are: small volume, simple structure, small influence of self-weight, high sensitivity; can eliminate the influence of load eccentricity, high precision; The contact force in one direction can be used for academic research as well as for industrial measurement.

Description

A Medium Range Three-Dimensional Force Sensor

technical field

The invention relates to the technical field of force measurement, in particular to a medium-range three-dimensional force sensor.

Background technique

By studying the animal movement, the contact force between the animal's sole and the crawling surface, the law of animal movement in a complex environment can be revealed, and the bionic mechanics of the motion mechanism and gait can be provided for the design of robots that can adapt to various working conditions. material.

In 1994, Zhang Guohua of Tsinghua University and others developed a three-dimensional force measurement system for parallel bars. The system is composed of 4 three-dimensional load cells installed on the four feet of the parallel bars, dynamic strain gauges, and 7T17S digital signal processor, which can provide various real-time processed measurement data and graphics. Through the actual test of the athletes, relatively satisfactory results have been obtained, which can be used in the actual training of parallel bars athletes. The sensor adopts the radial compression ring combined with the cylindrical bending form to measure the three-dimensional force. Strain gauge group full bridge. The vertical direction (z direction) range is 2000N, the horizontal direction (x, y direction) range is 1000N, and the force measurement error is within 5%.

In 2002, Sun Yining of Hefei Institute of Intelligent Machinery and others designed a new type of three-dimensional force sensor. Considering the characteristics of dynamic performance and static calibration index of the traditional mechanical quantity sensor, the sensitivity of each dimension and the coupling coefficient between dimensions are fully considered. The structural design achieves good sensitivity to the force of the measured dimension, and is as insensitive as possible to the force of the non-measured dimension, so that the coupling between dimensions is small, and at the same time, the entire structure has sufficient stiffness. The force range of the three directions is 0~3000N.

In 1998, the three-dimensional force sensor was jointly developed by the School of Mechanical Engineering of Nanyang Technological University in Singapore and WL.Jin of the Department of Mechanical Engineering of the University of California, Berkeley. Silicon-gold covalent bond technology is integrated together. Each of the four diaphragms of the sensor element is integrated with two Wheatstone bridges. The external force acts on the bearing layer and transmits it to the elastic layer through the silicon cross sensor of the sensitive layer. The elastic layer The displacement is transmitted to the diaphragm of the sensitive layer in the form of shear force and axial force, and is detected by a Wheatstone bridge.

The existing medium-range three-dimensional force sensors on the market are either large in size, low in accuracy, or expensive, and are not completely suitable for scientific research and market application requirements. Therefore, it is necessary to develop a three-dimensional force sensor with high precision, small size, easy installation and relatively cheap.

Contents of the invention

The object of the present invention is to provide a medium-range three-dimensional force sensor to overcome the above-mentioned shortcomings in the prior art.

The purpose of the present invention is to realize through the following technical solutions:

A medium-range three-dimensional force sensor, including a loading boss, the center of the loading boss is provided with a central threaded hole; the outer side of the loading boss is horizontally provided with a front rectangular beam, a rear rectangular beam, and a left rectangular beam distributed in a cross and the right rectangular beam, the upper and lower sides of the left rectangular beam and the right rectangular beam are respectively provided with strain gauges R1 and R2, strain gauges R4 and R3 near the loading boss, and the left rectangular beam and the right rectangular beam are left , The parts on the upper right sides close to the loading boss are provided with strain gauges R5 and R8, strain gauges R6 and R7 respectively, and the parts on the left and right sides of the front rectangular beam and the rear rectangular beam near the loading boss are respectively Strain gauges R9 and R12, strain gauges R10 and R11 are provided; the outer ends of the front rectangular beam, the rear rectangular beam, the left rectangular beam and the right rectangular beam are all connected with fixed bosses, and the centers of the fixed bosses are all provided with There are fixing holes; the first connecting terminal, the second connecting terminal and the third connecting terminal are arranged on the fixing boss.

Further, the strain gauges R1, R2, R3 and R4 form a Wheatstone full bridge, and the voltage measurement terminal is connected to terminal one.

Further, the strain gauges R5, R6, R7 and R8 form a Wheatstone full bridge, and connect the voltage measurement terminal to the terminal two.

Further, the strain gauges R9, R10, R11 and R12 form a Wheatstone full bridge, and connect the voltage measurement terminal to terminal three.

Further, the front rectangular beam and the rear rectangular beam are coaxial, the left rectangular beam and the right rectangular beam are coaxial, the front rectangular beam and the left rectangular beam are perpendicular to each other, and the front rectangular beam, rear rectangular beam, left The intersection of the centerlines of the rectangular beam and the right rectangular beam coincides with the center of the loading boss.

Further, the height of the loading boss is greater than that of the fixing boss.

The beneficial effects of the present invention are: small size, simple structure, small influence of self-weight, high sensitivity; can eliminate the influence of load eccentricity, high precision; can accurately test the X, Y, Z three dimensions of a larger creature (such as a person) during movement. The contact force in one direction can be used for academic research as well as for industrial measurement.

Description of drawings

The present invention will be described in further detail below according to the accompanying drawings.

Fig. 1 is a schematic structural view of a medium-range three-dimensional force sensor according to an embodiment of the present invention;

Figure 2 is a sectional view of the bottom view of Figure 1;

Fig. 3 is a Wheatstone full-bridge circuit diagram composed of strain gauges R1, R2, R3 and R4 according to the embodiment of the present invention;

Fig. 4 is a Wheatstone full-bridge circuit diagram composed of strain gauges R5, R6, R7, R8 according to the embodiment of the present invention;

Fig. 5 is a Wheatstone full-bridge circuit diagram composed of strain gauges R9, R10, R11 and R12 according to the embodiment of the present invention;

Fig. 6 is a structural block diagram of a data acquisition device for a medium-range three-dimensional force sensor according to an embodiment of the present invention.

In the picture:

R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12: strain gauges;

1. Fixed boss; 2. Front rectangular beam; 3. Rear rectangular beam; 4. Left rectangular beam; 5. Right rectangular beam; 6. Loading boss; 7. Fixing hole; 8. Central threaded hole; U, DC Power supply; Ui, voltage measuring terminal; Ⅰ, terminal 1; Ⅱ, terminal 2; Ⅲ, terminal 3.

Detailed ways

As shown in Figures 1-6, a medium-range three-dimensional force sensor described in the embodiment of the present invention includes a loading boss 6, and the center of the loading boss 6 is provided with a central threaded hole 8; the loading boss 6 The front rectangular beam 2, the rear rectangular beam 3, the left rectangular beam 4 and the right rectangular beam 5 are horizontally arranged on the outer side, and the upper and lower sides of the left rectangular beam 4 and the right rectangular beam 5 are close to the loading boss 6. The parts are respectively provided with strain gauges R1 and R2, strain gauges R4 and R3, and the left and right sides of the left rectangular beam 4 and the right rectangular beam 5 are respectively provided with strain gauges R5, R8, Strain gauges R6 and R7, strain gauges R9 and R12, strain gauges R10 and R11 are respectively provided on the left and right sides of the front rectangular beam 2 and the rear rectangular beam 3 near the loading boss 6; The outer ends of the beam 2, the rear rectangular beam 3, the left rectangular beam 4 and the right rectangular beam 5 are all connected with a fixed boss 1, and the center of the fixed boss 1 is provided with a fixing hole 7; There are terminal one I, terminal two II and terminal three III.

The front rectangular beam 2 and the rear rectangular beam 3 are coaxial, the left rectangular beam 4 and the right rectangular beam 5 are coaxial, the front rectangular beam 2 and the left rectangular beam 4 are perpendicular to each other, the front rectangular beam 2, the rear rectangular beam The intersection of the centerlines of the rectangular beam 3 , the left rectangular beam 4 and the right rectangular beam 5 coincides with the center of the loading boss 6 .

The height of the loading boss 6 is greater than that of the fixing boss 1 . There is a gap of 0.5 mm between the bottom surface of the loading boss 6 and the bottom surface of the fixed boss 1 for mechanical protection, and the upper surface of the loading boss 6 is about 2 mm higher than the fixed boss 1 to facilitate loading.

The front rectangular beam 2, the rear rectangular beam 3, the left rectangular beam 4 and the right rectangular beam 5 are all thinner rectangular beams.

As shown in Figure 3, the strain gauges R1, R2, R3 and R4 form a Wheatstone full bridge, and the voltage measurement terminal Ui is connected to terminal 1; the strain gauges R1, R2, R4 and R3 are sequentially connected in series to form a Wheatstone bridge For a full bridge, one end of the voltage measurement terminal Ui is connected between R1 and R2, and the other end is connected between R3 and R4; one end of the DC power supply U is connected between R1 and R3, and the other end is connected between R2 and R4. The Wheatstone full bridge is used to measure the magnitude of the Z-direction force Fz shown in Fig. 1 or Fig. 2 .

As shown in Figure 4, the strain gauges R5, R6, R7 and R8 form a Wheatstone full bridge, and the voltage measurement terminal Ui is connected to terminal II II; the strain gauges R5, R6, R8 and R7 are sequentially connected in series to form a Wheatstone bridge For a full bridge, one end of the voltage measurement terminal Ui is connected between R5 and R6, and the other end is connected between R7 and R8; one end of the DC power supply U is connected between R5 and R7, and the other end is connected between R6 and R8. The Wheatstone full bridge is used to measure the magnitude of the Y-direction force Fy shown in Fig. 1 or Fig. 2 .

As shown in Figure 5, the strain gauges R9, R10, R11 and R12 form a Wheatstone full bridge, and the voltage measurement terminal Ui is connected to terminal III III; the strain gauges R9, R10, R12 and R11 are sequentially connected in series to form a Wheatstone bridge For a full bridge, one end of the voltage measurement terminal Ui is connected between R9 and R10, and the other end is connected between R11 and R12; one end of the DC power supply U is connected between R9 and R11, and the other end is connected between R10 and R12. The Wheatstone full bridge is used to measure the magnitude of the X-direction force Fx shown in Fig. 1 or Fig. 2 .

Through the strain gauge bridge circuit shown in Fig. 3, Fig. 4 and Fig. 5, the resistance value change of the strain gauge on the medium-range three-dimensional force sensor is converted into a voltage change and output.

When in use, fix the four fixed bosses 1 on the foundation respectively with bolts, connect the loading boss 6 with the bearing plate, and connect the three voltages drawn from terminal one I, terminal two II and terminal three III The voltage measured by the measuring terminal Ui is amplified by the amplifier circuit for data collection, and the collected data is imported into the PC terminal (Figure 6).

When a force in the Z direction is applied to the top of the loading boss 6, the horizontal beam is bent, and large strains will be generated at both ends. Through the strain gauges R1, R2, R3, and R4 of the first group of electric bridges, the strain values on the upper and lower surfaces of the horizontal beam can be measured, and the magnitude of the force Fz in the Z direction can be converted; when the force in the X direction is applied to the top of the loading boss 6, the front The rectangular beam 2 and the rear rectangular beam 3 are simultaneously subjected to axial tension, compression and bending, and the left rectangular beam 4 and right rectangular beam 5 are simultaneously subjected to bending and torsion. Considering that the front rectangular beam 2 and the rear rectangular beam 3 are the main supports in this direction, the size of the force Fx in the X direction can be measured by selecting the bridges of strain gauges R9, R10, R11, and R12, and a larger strain can be obtained; According to the theory, the bridge group of strain gauges R5, R6, R7, and R8 can be used to measure the magnitude of the force Fy in the Y direction, and a larger strain can be obtained.

The overall size of the sensor is preferably in the range of 75mm×75mm×15mm, and the size of the rectangular cross-section beam is preferably 13mm×8mm×4mm. The measurement range is preferably 2000N for Fz, and 1000N for Fx and Fy.

The present invention is not limited to the above-mentioned best implementation mode, anyone can draw other various forms of products under the inspiration of the present invention, but no matter make any changes in its shape or structure, all those with the same or similar features as the present application Approximate technical solutions all fall within the protection scope of the present invention.

Claims (6)

1. A medium-range three-dimensional force sensor, including a loading boss (6), characterized in that: the center of the loading boss (6) is provided with a central threaded hole (8); the outer side of the loading boss (6) The front rectangular beam (2), the rear rectangular beam (3), the left rectangular beam (4) and the right rectangular beam (5) are arranged horizontally, and the left rectangular beam (4) and the right rectangular beam (5) Strain gauges R1 and R2, strain gauges R4 and R3 are respectively provided on the upper and lower sides close to the loading boss (6), and the left and right sides of the left rectangular beam (4) and right rectangular beam (5) are biased Strain gauges R5 and R8, strain gauges R6 and R7 are respectively provided on the upper part close to the loading boss (6), and the left and right sides of the front rectangular beam (2) and the rear rectangular beam (3) are close to the loading boss The parts of the platform (6) are respectively equipped with strain gauges R9 and R12, strain gauges R10 and R11; the front rectangular beam (2), the rear rectangular beam (3), the left rectangular beam (4) and the right rectangular beam (5) The outer ends of each are connected with a fixed boss (1), and the center of the fixed boss (1) is provided with a fixing hole (7); the fixed boss (1) is provided with a connecting terminal (I), Terminal two (Ⅱ) and terminal three (Ⅲ). 2. A medium-range three-dimensional force sensor according to claim 1, characterized in that: the strain gauges R1, R2, R3 and R4 form a Wheatstone full bridge, and the voltage measurement terminal (Ui) is connected to the wiring Terminal one (I). 3. A medium-range three-dimensional force sensor according to claim 2, characterized in that: the strain gauges R5, R6, R7 and R8 form a Wheatstone full bridge, and the voltage measurement terminal (Ui) is connected to the wiring Terminal two (Ⅱ). 4. A medium-range three-dimensional force sensor according to claim 3, characterized in that: the strain gauges R9, R10, R11 and R12 form a Wheatstone full bridge, and the voltage measurement terminal (Ui) is connected to the wiring Terminal three (Ⅲ). 5. A medium-range three-dimensional force sensor according to claim 4, characterized in that: the front rectangular beam (2) and the rear rectangular beam (3) are coaxial, and the left rectangular beam (4) and the right rectangular beam The beams (5) are coaxial, the front rectangular beam (2) and the left rectangular beam (4) are perpendicular to each other, the front rectangular beam (2), the rear rectangular beam (3), the left rectangular beam (4) and the right rectangular beam The centerline intersection of the beam (5) coincides with the center of the loading boss (6). 6. A medium-range three-dimensional force sensor according to claim 5, characterized in that: the height of the loading boss (6) is greater than the height of the fixing boss (1).

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