Disclosure of Invention
In view of the above, an object of the present invention is to provide an electromagnetic spring intelligent vibration absorber, which has a simple structure, a good vibration absorbing effect, and an optimal vibration absorbing performance in a wide frequency range, in order to overcome the disadvantages of the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme: an electromagnetic spring intelligent shock absorber comprises a shock absorber body and a shock absorber control unit;
the shock absorber body comprises a cylinder, a connecting rod penetrating through the upper end and the lower end of the cylinder is movably connected in the cylinder, a movable permanent magnet is fixed on the connecting rod, and the movable permanent magnet moves up and down in the cylinder along with the movement of the connecting rod; a first fixed permanent magnet is fixed at the top end in the cylinder, a second fixed permanent magnet is fixed at the bottom end in the cylinder, the magnetic pole directions of the first fixed permanent magnet and the second fixed permanent magnet are the same, and the magnetic pole directions of the first fixed permanent magnet and the second fixed permanent magnet are opposite to the magnetic pole direction of the movable permanent magnet; a coil is wound on the wall of the cylinder, and the winding position of the coil corresponds to the moving range of the moving permanent magnet in the cylinder;
the shock absorber control unit comprises a sensing module, a control module and an execution module, wherein the sensing module is connected with the connecting rod and is used for acquiring the value of the vibration acceleration of the object to be measured at any time and transmitting the acquired information to the control module; the control module is used for receiving the information of the sensing module, processing the information and then transmitting the information for controlling the corresponding output current to the execution module; the execution module is used for receiving the current information transmitted by the control module. The first fixed permanent magnet, the fixed permanent magnet of second and remove the permanent magnet and be neodymium iron canopy permanent magnet, the first fixed permanent magnet, the fixed permanent magnet of second and the diameter that removes the permanent magnet is 30mm, and thickness is 4mm, the first fixed permanent magnet with magnetism interval between the fixed permanent magnet of second is 10-30 mm.
The distance between the cylinder wall and the movable permanent magnet is 1-2 mm.
The sensing module is a JY901 nine-axis accelerator.
The control module is AVRATMEGA328 singlechip.
The execution module is a Z6005S direct-current stabilized power supply module.
The electromagnetic spring vibration absorber has the characteristics of simple structure, small volume, good vibration absorbing effect, low cost, convenience in installation and the like, and in addition, the device has an intelligent vibration absorbing function, has optimal vibration absorbing performance in a wider frequency range, is strong in adaptability, and can carry out vibration absorbing control on vibration in different directions under the condition of not changing the structure.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
An electromagnetic spring intelligent shock absorber comprises a shock absorber body 71 and a shock absorber control unit;
as shown in fig. 1, the damper body 71 includes a cylinder 2, a connecting rod 6 penetrating through the upper and lower ends of the cylinder 2 is movably connected to the inside of the cylinder 2, a movable permanent magnet 3 is fixed to the connecting rod 6, and the movable permanent magnet 3 moves up and down in the cylinder 2 along with the movement of the connecting rod 6; a first fixed permanent magnet 1 is fixed at the top end in the cylinder 2, a second fixed permanent magnet 5 is fixed at the inner bottom end of the cylinder 2, the magnetic pole directions of the first fixed permanent magnet 1 and the second fixed permanent magnet 5 are the same, the magnetic pole directions of the first fixed permanent magnet 1 and the second fixed permanent magnet 5 are both opposite to the magnetic pole direction of the movable permanent magnet 3, that is, the acting forces of the first fixed permanent magnet 1 and the second fixed permanent magnet 5 on the movable permanent magnet 3 are repulsive force, and N, S in fig. 1 represents the magnetic pole of the permanent magnet; the cylinder wall of the cylinder 2 is wound with a coil 4, the winding position of the coil 4 corresponds to the moving range of the movable permanent magnet 3 in the cylinder 2, and direct current is introduced into the coil 4 in the vibration reduction process.
The first fixed permanent magnet 1, the second fixed permanent magnet 5 and the movable permanent magnet 3 are arranged on the same line to jointly form an electromagnetic spring.
The rigidity of the electromagnetic spring is composed of a main rigidity (k) and an additional rigidity (k)1) The main rigidity is generated by the repulsion force between the fixed permanent magnet and the movable permanent magnet 3, and the size of the main rigidity can be changed by changing the size of the magnetic spacing between the fixed permanent magnets; the additional stiffness is generated by the force of the magnetic field generated by the energized coil on the moving permanent magnet 3, the magnitude of the additional stiffness is determined by the magnitude of the current in the coil, and the positive and negative of the additional stiffness are determined by the direction of the current.
From the arrangement of the permanent magnets shown in fig. 1, it can be known that the acting forces of the fixed permanent magnets to the moving permanent magnet 3 are repulsive forces, and the acting forces of the upper and lower fixed permanent magnets to the moving permanent magnet 3 are respectively F when the moving permanent magnet 3 is in the middle position without considering the gravity of the moving permanent magnet 31、F2Then, there are: f ═ F1+F2=0
When the moving permanent magnet 3 leaves the equilibrium position, there are:
where α is a polynomial coefficient, Z is a distance of movement of the permanent magnet, and m is a highest power of the polynomial. In order to determine these parameters, the force applied to the moving permanent magnet 3 during the vibration process in the magnetic spacing is simulated by Maxwell software, the permanent magnet is made of strong-magnetic neodymium-iron-boron material, the diameter of the permanent magnet is 30mm, the thickness of the permanent magnet is 4mm, the spacing between the fixed permanent magnets is 60mm, and the simulation result is shown in fig. 2. And fitting the data to different powers to obtain:
y=-1.9969x+63.959
y=-0.0031x3+0.2984x2-10.114x+120.36
y=-0.000004x5+0.0007x4-0.0455x3+1.4169x2-22.849x+167.89
as can be seen from FIG. 2 and the fitting data, the result of the fifth power fitting on the discrete data is already accurate, and the fitting determines the coefficient R2To 0.9986, the cubic fitting results are also satisfactory, and the fitting determines the coefficient R20.9016, it can be seen from the distribution trend of the discrete data that when the moving permanent magnet 3 moves greatly in the space with the magnetic spacing of 60mm, the stiffness of the electromagnetic spring is nonlinear overall; the electromagnetic spring rate has a linear nature when the moving permanent magnet 3 moves with a small amplitude near the equilibrium position.
The relationship between the electromagnetic spring and the current is discussed below, based on the electromagnetic induction theory, a magnetic field is generated in the middle of the electrified coil, and the additional magnetic field can enhance or weaken the magnetic field generated by the permanent magnet in the cylinder 2, so that the rigidity of the electromagnetic spring is changed. In order to linearize the rigidity of the electromagnetic spring, a current condition is added into the model, the magnetic spacing is reduced to 10mm, the vibration process of the moving permanent magnet 3 is simulated, the current is set to six gears of 0-5A without loss of generality, namely, no current exists in a coil at 0A, the additional rigidity is zero, and the simulation data is subjected to linear fitting and processing to obtain the additional rigidity k1The relationship with the current is shown in table 1.
TABLE 1 additional stiffness vs. input Current
The data were fitted and the additional stiffness was found to have a significant linear relationship with current as shown in figure 3. Coefficient of fit determination R2Up to 0.9996, the relationship between the additional stiffness and current is:
k1=291.37i-12.095
wherein k is1For the additional stiffness of the electromagnetic spring, i is the value of the current in the coil. When the magnetic spacing is 10mm, the main stiffness of the simulated electromagnetic spring is 27043N/m, and the relation between the total stiffness (k) of the electromagnetic spring and the current obtained by processing the data is as follows:
k=27043+291.37i-12.095
the rigidity of the intelligent vibration absorber is provided by the electromagnetic spring, and the stability of the rigidity of the vibration absorber has obvious influence on the performance of the vibration absorber according to the principle of the dynamic vibration absorber. As can be seen from fig. 2, the stiffness of the electromagnetic spring is non-linear, and the degree of non-linearity is closely related to the magnetic spacing. In order to ensure the linearization of the stiffness of the electromagnetic springs, the electromagnetic springs with different magnetic distances are simulated, assuming that the movable permanent magnet 3 vibrates in a space of 3mm near the equilibrium position in the working process of the intelligent shock absorber, the magnetic distance ranges from 10mm to 80mm, the Maxwell software is applied to the simulation once every 0.1mm sampling, and the simulation data are subjected to linear fitting, and the result is shown in fig. 3. It is apparent from the figure that the smaller the magnetic spacing, the higher the degree of linearization of the stiffness, and with the increase of the magnetic spacing, not only the stiffness is reduced, but also the nonlinearity is highlighted, and the stiffness and the fitting determination coefficient of the electromagnetic springs with different magnetic spacings are shown in table 2.
The data in Table 2 show that within 30mm of magnetic spacing, the rigidity is in a sharp decline trend along with the increase of the magnetic spacing, the linearization degree of the rigidity is very high, R2Can reach above 0.995; when the magnetic spacing is beyond 30mm, the rigidity is small, the change tends to be stable, the rigidity linearization degree is obviously reduced, and particularly when the magnetic spacing is 80mm, R2Up to 0.613, the stiffness loses almost linear properties. To verify the linear nature of the stiffness near equilibrium of the moving permanent magnet 3 at a positive magnetic spacing of 80mm, assuming a spatial vibration of 1.5mm near equilibrium of the moving permanent magnet 3,sampling is carried out every 0.05mm, experimental data and a linear fitting result are shown in the last sub-graph in the graph 3, a fitting decision coefficient is 0.323, and a simulation result shows that when the magnetic spacing is increased to a certain degree, the degree of rigidity linearization generated by the vibration of the movable permanent magnet 3 near the balance position is also very low, and at the moment, the intelligent vibration absorber almost loses the vibration attenuation effect; on the other hand, since the moving permanent magnet 3 itself has a thickness and a certain movement space is necessary, the magnetic pitch cannot be too small. In summary, the magnetic spacing in the intelligent vibration damper should be in the range of 10-30mm, and the magnetic spacing should be as small as possible under the condition that the magnitude of the principal rigidity is satisfied.
TABLE 2 fitting stiffness and determining coefficient of intelligent vibration damper with different magnetic spacing
Besides the rigidity parameter, the damping coefficient also has great influence on the vibration damping function of the intelligent vibration damper, the damping of the intelligent vibration damper of the invention is composed of two parts, one part is eddy current damping generated by the relative movement of the magnets; another part is caused by the friction of the relative movement between the moving permanent magnet 3 and the wall of the cylinder 2. The former is inevitable, the latter can be eliminated by increasing the inner diameter of the wall of the cylinder 2, but the excessive inner diameter of the wall of the cylinder 2 has an influence on the additional rigidity. In summary, the distance between the wall of the cylinder 2 and the movable permanent magnet 3 is 1-2 mm.
The parameters of the shock absorber include mass, rigidity and damping. From the principle of the dynamic vibration absorber, it can be known that when the natural frequency of the vibration absorber is equal to the vibration frequency of the object to be damped, the vibration damping effect is optimal, i.e. the amplitude of the primary system is minimized. The intelligent vibration absorber is characterized in that the vibration absorber can automatically adjust self parameters according to different vibration frequencies of a vibration-absorbing object, so that the condition of optimal vibration absorbing effect is met, and the vibration absorber can achieve the optimal vibration absorbing effect under different working conditions. The intelligent shock absorber can automatically adjust the rigidity based on the electromagnetic spring, and the electromagnetic spring is used as a rigidity element of the shock absorber.
The shock absorber control unit comprises a sensing module 72, a control module 73 and an execution module 74, wherein the sensing module 72 is connected with the connecting rod 6, the sensing module 72 is used for acquiring the value of the vibration acceleration of a measured object at any time and transmitting the acquired information to the control module 73, and the sensing module 72 is a JY901 nine-axis accelerometer; the control module 73 is configured to receive the information of the sensing module 72, process the information, and transmit information for controlling a corresponding output current to the execution module 74, where the control module 73 is an AVR ATMEGA328 single chip microcomputer; the execution module 74 is used for receiving the current information sent by the control module and then outputting the corresponding steady current, so as to change the rigidity of the intelligent damper, namely change the natural frequency of the intelligent damper, wherein the execution module 74 is a Z6005S direct current stabilized power supply module. The flow chart of the intelligent control logic is shown in fig. 5.
The invention discloses an intelligent shock absorber experimental test:
the vibration testing platform is set up, the schematic diagram and the experimental diagram show that the vibration damping performance of the intelligent vibration damper is tested as shown in fig. 6, specifically, the vibration damper body 71 and the sensing module 72 thereof are arranged on the clamped beam 76, the vibration exciter 75 is arranged below the clamped beam 76, the sensing module 72, the control module 73, the execution module 74 and the vibration damper body 71 are sequentially connected in series, and the power supply 77 is responsible for supplying power. Because the 1 st order frequency of the damped clamped beam 76 is 42Hz, the magnetic spacing is adjusted within the allowed range, the main rigidity of the intelligent damper is 2000N/m, meanwhile, the movable permanent magnet 3 is taken as a vibrator of the damper body 71 in consideration of the self gravity factor of the intelligent damper, the connecting rod 6 is fixed with the permanent magnets at the two ends, so that the movable permanent magnet can freely slide on the connecting rod 6, and the mass of the movable permanent magnet 3 is 30 g. The relation between the total stiffness of the intelligent vibration damping and the current is known from the relation formula between the additional stiffness and the current as follows:
k=2000+291.37i-12.095
in the design, in order to simplify the procedure and without losing generality, the current output is set to six gears of 0-5A, namely the current maximum output is 5A, and the natural frequency calculation formula and the formula can be known as follows: the relationship between the current and the natural frequency of the intelligent shock absorber is as follows:
finally, the rigidity of the intelligent damper 71 can be adjusted within the range of 1988N/m-3445N/m, and the natural frequency of the intelligent damper 71 can be adjusted within the range of 41Hz-54 Hz.
And recording the vibration acceleration values of the beam under the working conditions of different excitation frequencies without the action of a shock absorber, a common shock absorber and an intelligent shock absorber, wherein the common shock absorber is the intelligent shock absorber without a control system, and no current exists in a coil. The results of the experiment are shown in FIG. 4. The experimental results show that: the intelligent vibration absorber has good vibration attenuation performance, the vibration attenuation effect is obviously superior to that of a common vibration absorber, and particularly, when a vibration-attenuated beam resonates, the vibration attenuation effect of the intelligent vibration absorber is particularly outstanding. The adjustable frequency band of the intelligent shock absorber is 14Hz, the intelligent shock absorber has strong environment adaptability, and the intelligent shock absorber has good shock absorption effect under different excitation working conditions within the adjustable frequency band range. The intelligent shock absorber has two performances of intelligence and common performance, and when the external stress working condition is not changed greatly, the control system of the intelligent shock absorber can be closed to be used as a common shock absorber, so that the consumption of electric energy is reduced.
Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.