Linear low-frequency active dynamic vibration absorption device and plane arrangement method

Abstract

The invention discloses a linear type low-frequency active dynamic vibration absorption device and a plane arrangement method, and relates to the technical field of mechanical arm control technologies, the linear type low-frequency active dynamic vibration absorption device comprises a carbon fiber base, the periphery of the carbon fiber base is in bolted connection with three carbon fiber sensor fixing seats, and the carbon fiber sensor fixing seats are in bolted connection; the three carbon fiber sensor fixing seats are distributed in an array mode with the center of the carbon fiber base as the circle center, laser displacement sensors are installed on the outer sides of the carbon fiber sensor fixing seats, and an acceleration sensor is fixedly connected to the center of the carbon fiber base. A winding assembly is installed between each acceleration sensor and the laser displacement sensor. A brand new dynamic vibration absorber scheme is designed, compared with a traditional linear dynamic vibration absorber, force synthesis is related to a plane distribution form and has diversity, vibration suppression force synthesis in different scenes is more accurate, the vibration suppression effect is better, meanwhile, the mass is lighter, the stroke is smaller, and the vibration suppression effect is better. And the situation that additional vibration is generated due to the fact that vibration absorbers are additionally arranged is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical arm control, and in particular to a linear low-frequency active dynamic vibration absorber and a planar arrangement method. BACKGROUND

[0002] In the application of flexible mechanical arms, the end vibration problem is particularly prominent. First, due to the elastic deformation of the mechanical arm connecting rod, especially in the case of sudden change in motion state or excessive acceleration change, the end of the mechanical arm will experience violent oscillation, affecting its positioning accuracy and stability. Second, the joint driving torque of the mechanical arm is usually provided by a harmonic reducer, and the flexible characteristics of the harmonic reducer itself cause a certain degree of deformation of the joint when bearing load. This flexible effect affects the torque transmission of the joint and can cause instability of the joint control. When the flexibility of the joint is large, the torque output in the transmission system can appear lag or irregular change, thereby causing additional vibration at the end.

[0003] In the vibration suppression strategy of flexible arms, the most typical representative is the dynamic vibration absorber. At present, the proportional electromagnetic active vibration absorber with a "shear type" magnetic pole surface structure has a certain effect on the suppression of simple harmonic periodic excitation force, but there is a large gap between its vibration frequency and the resonance frequency of itself, resulting in too small driving force, and the acceleration response under 50Hz cannot be effectively controlled. The vibration reduction effect of the ground-hook control strategy based on displacement and speed is better, but the additional excitation form involved is time-invariant simple harmonic excitation, and the frequency change range is limited. At the same time, for the low-frequency vibration of the space mechanical arm, the traditional linear motion dynamic vibration absorber scheme will have the problems of long stroke and heavy weight. There are many end vibration problems of flexible mechanical arms in low-frequency scenarios. SUMMARY

[0004] The purpose of the present application is to provide a linear low-frequency active dynamic vibration absorber and a planar arrangement method and system to solve the problem of end vibration of the prior art flexible mechanical arm.

[0005] To solve the above technical problems, the present application provides the following technical scheme:

[0006] A linear low-frequency active dynamic vibration absorber, comprising: a carbon fiber base, the carbon fiber base is externally bolted with three carbon fiber sensor fixing seats, the three carbon fiber sensor fixing seats are arrayed with the center of the carbon fiber base as the center, a laser displacement sensor is installed outside the carbon fiber sensor fixing seat, an acceleration sensor is fixedly connected at the center position of the carbon fiber base, and a winding assembly is installed between each acceleration sensor and laser displacement sensor.

[0007] Further, the winding assembly comprises two carbon fiber shaft cylinder fixing seats, and the carbon fiber shaft cylinder fixing seats are fixedly connected together.

[0008] Further, the carbon fiber base and the carbon fiber shaft cylinder are made of T300 carbon fiber material, can normally work in high temperature of 120-180 DEG C, have 8 times of tensile strength of ordinary steel material, have better elastic modulus than steel material, have excellent impact resistance, are not easy to oxidize, and the steel material is 3.9 times of the mass of the carbon fiber material under the same volume.

[0009] Further, the carbon fiber base serves as a vibration absorber bottom plate, has a thickness of 5 mm, and has a bottom plate area of 544 cm 2 The carbon fiber shaft cylinder is wound with copper wire winding outside, and is internally provided with 304 stainless steel spring and component N52 neodymium iron boron strong magnet, and the mover stroke is 50 mm.

[0010] Further, the enameled wire bare wire diameter of the copper wire winding is 0.5 mm, the winding direction is counterclockwise along the main shaft, the wire head and tail are left for 150 mm, three layers are wound, 500 mpa·s adhesive is used for bonding, and the temperature resistance interval is -55 DEG C to 125 DEG C.

[0011] Further, the laser displacement sensor has a detection range of 35-65 mm and a detection accuracy of 30 um, and has a single mass of 85 g, small volume and light weight, the piezoelectric crystal impedance converter circuit in the acceleration sensor converts the electric charge generated by the vibration element during impact or vibration into voltage output, and is fixedly connected with the carbon fiber base through the bottom screw hole.

[0012] Further, the carbon fiber base is fixed with a carbon fiber mechanical arm connecting piece, the carbon fiber sensor fixing seat and the carbon fiber mechanical arm connecting piece are non-standard parts, and the carbon fiber shaft cylinder fixing seat is made of carbon fiber reinforced modified nylon material.

[0013] Further, a planar arrangement method of a linear low-frequency active dynamic power vibration absorbing device comprises the following steps:

[0014] Guowei linear DC power supply, power amplifier, linear low-frequency vibration absorber, acceleration sensor, laser displacement sensor, KISTLER 5134 piezoelectric coupler, PCI-6221 adapter terminal plate, NI PCI-6221 multifunctional acquisition card and Linux real-time operating system;

[0015] The solid linear direct current power supply supplies power to the power amplifier, the power amplifier is connected with the linear low-frequency vibration absorber, the control current range is ±3A, the acceleration sensor in the linear low-frequency vibration absorber senses the buffeting from the mechanical arm, converts the generated electric charge into voltage, and transmits the voltage to the component Linux real-time operating system through a KISTLER 5134 piezoelectric coupler, a PCI-6221 adapter terminal board and an NI PCI-6221 multifunction acquisition card, and then performs FFT spectrum analysis.

[0016] Further, the vibration spectrum of the mechanical arm obtained after FFT spectrum analysis needs to be applied with vibration suppression force with the same frequency and opposite direction, and the corresponding current is output to three groups of copper wire windings through a power amplifier via an NI PCI-6221 multifunction acquisition card and a PCI-6221 adapter terminal board; the N52 neodymium iron boron strong magnet in the carbon fiber shaft cylinder moves under the action of the current, and the 304 stainless steel spring is correspondingly stretched and compressed; the following formula is followed on each shaft:

[0017] With ,

[0018] The generated vibration suppression resultant force acts on the whole vibration absorber to complete the vibration suppression of the mechanical arm, and the laser displacement sensor records the position of the magnet in the shaft cylinder at a period of one thousandth of a second, and the current size and direction output by the power amplifier are closed-loop controlled through the control algorithm built in the Linux real-time operating system.

[0019] Compared with the prior art, the beneficial technical effects of the present application are:

[0020] The present application designs a new dynamic vibration absorber scheme for the low-frequency vibration of the end of the mechanical arm, and compared with the traditional linear dynamic vibration absorber, the force synthesis and planar distribution form are related and diverse, so that the vibration suppression force synthesis is more accurate and the vibration suppression effect is more outstanding in different scenes, and the quality is lighter and the stroke is smaller, reducing the additional vibration caused by increasing the vibration absorber. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic view of a linear low-frequency active dynamic vibration absorber device provided by an embodiment of the present application;

[0022] Figure 2 is a half-section schematic view of a linear low-frequency active dynamic vibration absorber device provided by an embodiment of the present application;

[0023] Figure 3 is a schematic view of the internal structure of a carbon fiber shaft cylinder of a linear low-frequency active dynamic vibration absorber device provided by an embodiment of the present application;

[0024] Figure 4It is a platform connection schematic diagram of a linear low-frequency active dynamic vibration absorber arrangement method provided by the embodiment of the application.

[0025] Figure 5 It is a flowchart of a linear low-frequency active dynamic vibration absorber arrangement method provided by the embodiment of the application.

[0026] 1, laser displacement sensor; 2, carbon fiber shaft cylinder fixing seat; 3, acceleration sensor; 4, carbon fiber bottom plate; 5, copper wire winding; 6, carbon fiber sensor fixing seat; 7, carbon fiber mechanical arm connecting piece; 8, 304 stainless steel spring; 9, N52 neodymium iron boron strong magnet; 10, carbon fiber shaft cylinder; 11, Guwei linear DC power supply; 12, power amplifier; 13, linear low-frequency vibration absorber; 16, KISTLER 5134 piezoelectric coupler; 17, PCI-6221 adapter terminal plate; 18, NI PCI-6221 multifunctional acquisition card; 19, Linux real-time operating system. DETAILED DESCRIPTION

[0027] The features and exemplary embodiments of various aspects of the present application will be described below in detail, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0028] It should be noted that in this paper, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0029] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present application; "a plurality of" appearing in the present application means two or more (including two).

[0030] In the plane, it can be divided into various combination structures in a distributed manner, please refer to Figure 2 , the multi-axis distributed topology coil mover is uniformly distributed in the plane according to 120°, 90°, 72° angle, and the output force of vibration suppression is derived from the ampere force generated by the coil mover on the shaft. In the Cartesian coordinate system, the coil mover is equal to R from the center point, and the output force on each shaft is F1, F2, F3, F4, F5 (equal to the number of shafts), and the resultant force in X, Y is respectively:

[0031] (a) (b)

[0032] (c)

[0033] The system output vibration suppression force is the resultant force in X, Y, which follows , wherein the three-axis resultant force in the θ direction is , except that the distribution manner and the calculation of the resultant force generated thereby are different, the structure and control are basically the same, and a three-axis is taken as an example (hereinafter referred to as a linear low-frequency vibration absorber) for physical introduction.

[0034] Please refer to Figure 1 , the carbon fiber bottom plate 4 and the carbon fiber shaft cylinder 10 of the linear low-frequency dynamic vibration absorber 13 are made of T300 carbon fiber material, which can work normally in high temperature of 120℃-180℃, has 8 times the tensile strength of ordinary steel material, the elastic modulus is better than that of steel material, the impact resistance is excellent, and the same volume of steel material is 3.9 times the mass of carbon fiber material. The former is used as the vibration absorber bottom plate, the thickness is 5mm, the bottom plate area is 544cm 2 ; the latter is wound with copper wire winding 5, internally provided with 304 stainless steel spring 8 and N52 neodymium iron boron strong magnet 9, and the mover stroke is 50mm, which constitutes the main actuator part of the vibration absorber vibration suppression work.

[0035] Please refer to Figure 3 , the enameled wire bare wire diameter of the copper wire winding 5 is 0.5mm, the winding direction is counterclockwise along the main shaft, the wire head and tail are left for 150mm, three layers are wound, 500mpa·s adhesive is used for bonding, the temperature resistance interval is -55℃ to 125℃, which meets the working environment requirements.

[0036] The laser displacement sensor 1 has a detection range of 35-65 mm and a detection accuracy of 30 um, and a single mass of 85 g, small volume and light weight, and is fixed and connected by a carbon fiber sensor fixing seat 6 and a carbon fiber base 4 through bolts. The acceleration sensor 3 has excellent long-term stability, repeatability and measurement accuracy, low thermal sensitivity (temperature coefficient of 0.04%) and low base strain. The internal piezoelectric crystal impedance converter circuit converts the charge generated by the vibration element during impact or vibration into voltage output. It is connected and fixed with the carbon fiber base 4 through the bottom threaded hole.

[0037] The carbon fiber shaft cylinder fixing seat 2, the carbon fiber sensor fixing seat 6 and the carbon fiber mechanical arm connecting piece 7 are non-standard parts, and the strength and designability of the material are high. In addition to bearing the connection and fixing work with the bottom plate and the mechanical arm, the carbon fiber shaft cylinder fixing seat 2 also needs to ensure high elastic modulus, and the vibration suppression force generated by the vibration absorber actuator part cannot be absorbed. If a material with good plasticity such as resin is used to meet the designability requirements, the elastic modulus and strength are low, and it cannot meet the normal working requirements in small size parts. If steel or aluminum is used, the processing cost is high, and because the weight is large, it will generate a large external additional weight to the mechanical arm, which will further affect the working effect of the mechanical arm. Therefore, the modified nylon reinforced with carbon fiber has high strength, high modulus, designability and excellent friction and wear performance. The elastic modulus increases by 422%, the strength increases by 117%, the friction coefficient is between 0.21 and 0.24 (2000 rpm, 20 N), and the mass is light, the raw material price is low, and the forming processing is simple.

[0038] Please refer to Figure 4 A control platform constructed by a planar arrangement method of a linear low-frequency active dynamic vibration absorber device. A platform solid linear DC power supply 11 supplies ±24V power to a power amplifier 12. The power amplifier 12 is connected to a linear low-frequency vibration absorber 13. The current range is ±3A. The acceleration sensor 4 in the linear low-frequency vibration absorber 13 senses the buffeting from the mechanical arm and converts the generated charge into voltage through a KISTLER 5134 piezoelectric coupler 16, a PCI-6221 adapter terminal board 17, and a NI PCI-6221 multifunction acquisition card 18. The vibration spectrum of the mechanical arm obtained after FFT spectrum analysis needs to be applied with a vibration suppression force with the same frequency and opposite direction, and transmitted to the component Linux real-time operating system 19 through the NI PCI-6221 multifunction acquisition card 18, the PCI-6221 adapter terminal board 17, and the power amplifier 12. The corresponding current is output by the three groups of copper wire windings. The N52 neodymium iron boron strong magnet 9 in the carbon fiber shaft cylinder 10 moves under the action of the current, and the 304 stainless steel spring 8 is stretched and compressed accordingly. Each shaft follows:

[0039] With ,

[0040] The generated vibration suppression resultant force acts on the entire vibration absorber, completing the vibration suppression of the mechanical arm. The laser displacement sensor 5 records the position of the magnet in the shaft cylinder at a period of one thousandth of a second, and the size and direction of the current output by the power amplifier 12 are closed-loop controlled through the control algorithm built in the Linux real-time operating system 9.

[0041] Please refer to Figure 5 , the mechanical arm control is first obtained by the excitation test the vibration characteristics of the main structure in the low frequency band, according to which the vibration absorbing mass, stiffness and damping are initially selected, and the linear guide-spring-damping-mass integrated passive vibration absorber mechanical design is completed; after checking the frequency and attenuation effect by using finite element, the multi-objective arrangement optimization of the position and angle of the vibration absorber is carried out in the given plane area of the equipment, with the goals of not colliding with the installation hole, minimum additional mass and minimum kinetic energy of the main structure; then the voice coil motor, laser displacement and acceleration sensor are integrated on the vibration absorber, the fuzzy RBF adaptive PID algorithm is run in the embedded real-time system, and active force compensation is realized in addition to passive parameters; finally, the passive and active parameters are processed and assembled, calibrated, and the whole device is installed back to the main equipment for working condition verification, to further suppress the linear vibration.

[0042] The above is only the preferred specific embodiment of the present application, and is not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A linear low-frequency active dynamic vibration absorber comprising: The carbon fiber base (4) is characterized in that the carbon fiber base (4) is externally bolted with three carbon fiber sensor fixing seats (6), the three carbon fiber sensor fixing seats (6) are arrayed with the center of the carbon fiber base (4) as the center, the carbon fiber sensor fixing seat (6) is externally provided with a laser displacement sensor (5), the center of the carbon fiber base (4) is fixedly connected with an acceleration sensor (3), and each acceleration sensor (3) and laser displacement sensor (5) are provided with a winding assembly.

2. The linear low-frequency active dynamic vibration absorber according to claim 1, characterized in that: The winding assembly comprises two carbon fiber shaft cylinder fixing seats (2), and the two carbon fiber shaft cylinder fixing seats (2) are fixedly connected with a carbon fiber shaft cylinder (10) in common.

3. The linear low-frequency active dynamic vibration absorber according to claim 2, characterized in that: The carbon fiber base (4) and the carbon fiber shaft cylinder (10) are made of T300 carbon fiber material, can normally work in high temperature of 120-180 DEG C, have 8 times of tensile strength of ordinary steel material, have better elastic modulus than steel material, have excellent impact resistance, are not easy to be oxidized, and the mass of steel material is 3.9 times of the mass of the carbon fiber material under the same volume.

4. The linear low-frequency active dynamic vibration absorber according to claim 3, characterized in that: The carbon fiber base (4) is used as a vibration absorber bottom plate, with a thickness of 5 mm and a bottom plate area of 544 cm 2 The carbon fiber shaft cylinder (10) is wrapped with a copper wire winding (5) on the outer layer, and contains a 304 stainless steel spring (8) and a component N52 neodymium iron boron strong magnet (9) in the inner layer. The mover stroke is 50 mm.

5. The linear low-frequency active dynamic vibration absorber according to claim 4, characterized in that: The enameled wire bare wire diameter of the copper wire winding (5) is 0.5 mm, the winding direction is counterclockwise along the main shaft, the wire head and tail are left for 150 mm, three layers are wound, 500 mpa.s adhesive is used for bonding, and the temperature resistance interval is -55 DEG C to 125 DEG C.

6. The linear low-frequency active dynamic vibration absorber according to claim 1, characterized in that: The detection range of the laser displacement sensor (1) is 35-65 mm, the detection accuracy is 30 um, the single mass is 85 g, the volume is small, and the weight is light, the internal piezoelectric crystal impedance converter circuit of the acceleration sensor (3) converts the electric charge generated by the vibration element during impact or vibration into voltage output, and is connected and fixed with the carbon fiber base 4 through the bottom threaded hole.

7. The linear low-frequency active dynamic vibration absorber according to claim 1, characterized in that: The carbon fiber base (4) is fixed with a carbon fiber mechanical arm connecting piece (7), the carbon fiber sensor fixing seat (6) and the carbon fiber mechanical arm connecting piece (7) are non-standard parts, and the carbon fiber shaft cylinder fixing seat (2) is made of carbon fiber reinforced modified nylon material.

8. A planar arrangement method of a linear low-frequency active dynamic vibration absorber, characterized in that, It comprises a solidwei linear DC power supply (11), a power amplifier (12), a linear low-frequency vibration absorber (13), an acceleration sensor (4), a laser displacement sensor (5), a KISTLER 5134 piezoelectric coupler (16), a PCI-6221 adapter terminal board (17), an NI PCI-6221 multifunction acquisition card (18) and a Linux real-time operating system (19). The solidwei linear DC power supply (11) supplies power to the power amplifier (12) at ±24V, the power amplifier (12) is connected with the linear low-frequency vibration absorber (13), controls the current range of ±3A, the acceleration sensor (4) in the linear low-frequency vibration absorber (13) senses the buffeting from the mechanical arm, converts the generated electric charge into voltage, and transmits the voltage to the component Linux real-time operating system (19) through the KISTLER 5134 piezoelectric coupler (16), the PCI-6221 adapter terminal board (17) and the NI PCI-6221 multifunction acquisition card (18) for FFT spectrum analysis. ​ 9. The planar arrangement method of the linear low-frequency active dynamic vibration absorber according to claim 8, characterized in that: The vibration spectrum of the mechanical arm obtained by FFT spectrum analysis needs to apply frequency same and opposite direction vibration suppression force, and through the NI PCI-6221 multifunctional acquisition card (18), PCI-6221 adapter terminal board (17), the corresponding current is output by the power amplifier (12) to the three groups of copper wire winding; the N52 neodymium iron boron strong magnet (9) in the carbon fiber shaft cylinder (10) moves under the action of the current, and the 304 stainless steel spring (8) is correspondingly stretched and compressed, and each shaft follows: with , The generated vibration suppression resultant force acts on the whole vibration absorber to complete the vibration suppression of the mechanical arm, the laser displacement sensor (5) records the position of the magnet in the shaft cylinder at a period of one thousandth of a second, and the current size and direction output by the power amplifier (12) are closed-loop controlled through the control algorithm built in the Linux real-time operating system (9).

Images