Electromagnetic Nonlinear Sliding Mode Active Vibration Control Device and Method Based on Current Regulation

Abstract

An electromagnetic nonlinear sliding mode active vibration control device and method based on current regulation includes an electromagnetic nonlinear vibration isolator. The electromagnetic nonlinear vibration isolator is connected to a sensor and a signal acquisition unit, which is connected to a control unit. The control unit is connected to the electromagnetic nonlinear vibration isolator through an execution unit. Under given environmental excitation amplitude and frequency, the trajectory of the load in a low-energy track is measured and stored in the control unit as the desired trajectory. Then, the trajectory signal of the electromagnetic nonlinear vibration isolator is monitored in real time by the sensor. If the electromagnetic nonlinear vibration isolator is always in a low-energy track, no control is required. Once the electromagnetic nonlinear vibration isolator is disturbed and enters a high-energy track, the control unit starts sliding mode control. Finally, through sliding mode control, the electromagnetic nonlinear vibration isolator can be changed from a high-energy track to a low-energy track, and the quasi-zero stiffness vibration isolation system will be stabilized in the low-energy track, achieving the vibration isolation effect. This invention achieves vibration isolation on a low-energy track.

Description

Technical Field

[0001] This invention relates to the field of vibration control technology, specifically to an electromagnetic nonlinear sliding mode active vibration control device and method based on current regulation. Background Technology

[0002] Vibration control is crucial for the normal and stable operation of high-end equipment and has wide applications in many important industrial sectors, such as automotive, aerospace, shipbuilding, and precision manufacturing. During operation, this high-end equipment often endures significant amounts of harmful vibration excitation from the external environment or internal power units, which negatively impacts its overall performance. In the automotive industry, harmful vibrations severely affect passenger comfort; in aerospace, harmful engine vibrations can disrupt the normal operation of critical components; in shipbuilding, harmful engine vibrations can easily expose positional information; and in precision manufacturing, harmful vibrations can affect the manufacturing accuracy of products. Therefore, it is necessary to develop high-performance vibration control methods to suppress harmful vibrations.

[0003] Traditional vibration isolation methods employ linear spring-damping structures. However, according to vibration dynamics theory, this linear method is only effective when the excitation frequency is greater than a certain value. Vibration isolation is only effective when the natural frequency is doubled. To obtain a wider isolation bandwidth and lower the initial isolation frequency, the natural frequency needs to be lowered by increasing the load mass or reducing the system stiffness. However, the system load mass is generally fixed, while reducing the system stiffness will lead to insufficient static support capacity, making the isolation structure prone to failure. To overcome this problem, nonlinear vibration isolation technology has been extensively studied. Quasi-zero stiffness vibration isolation technology is one such method. By connecting positive stiffness elements in parallel with negative stiffness elements, it achieves low dynamic stiffness near the equilibrium position and high static stiffness far from the equilibrium position, ensuring that the system has a low natural frequency and high support capacity.

[0004] Electromagnetic force is widely used to provide negative stiffness due to its advantages such as non-contact operation, adjustability, and fast response. Because electromagnetic force has an adjustable current characteristic, it can be applied to vibration isolation environments with different load masses. Connecting an electromagnetic negative stiffness element in parallel with an elastic positive stiffness element can achieve an electromagnetic quasi-zero stiffness system; furthermore, electromagnetic force can be generated through the interaction between electromagnets or between an electromagnet and a permanent magnet.

[0005] As equipment service conditions become increasingly demanding and performance requirements rise, vibration isolators must withstand increasingly greater vibration excitations. However, under large excitation amplitude vibration conditions, these electromagnetic nonlinear vibration isolators are prone to failure. This is because the nonlinear characteristics cause the isolators to easily exhibit instability phenomena such as bifurcation and jumps under large excitation conditions, thus leading to performance degradation. To avoid this nonlinear phenomenon-induced performance degradation, Chinese patent (application number: CN202011589226.1) discloses a magnetically levitated quasi-zero stiffness electromagnetic vibration isolator with active negative stiffness. This isolator measures the displacement state of the negative stiffness mechanism in real time, and with the cooperation of a controller and driver, achieves real-time linear negative stiffness, avoiding multi-steady-state phenomena and preventing complex dynamic phenomena such as jumping during operation. However, a solution for nonlinear vibration isolation control under large excitation amplitude conditions remains unsolved. For nonlinear vibration isolators, when the vibration excitation amplitude increases to a certain extent, the isolator will exhibit multiple solutions. These multiple solutions are all stable equilibrium solutions, which will appear depending on the initial conditions and external disturbances. These stable equilibrium solutions typically include high-energy and low-energy orbits. On the high-energy orbit, the response amplitude of the isolator is usually large, which has a very detrimental effect on its vibration isolation performance. Conversely, on the low-energy orbit, the response amplitude of the isolator is smaller, effectively isolating the vibration. To ensure the performance of the isolator, it is necessary to maintain the nonlinear isolator in the low-energy orbit even under large-amplitude excitation vibration conditions. Therefore, how to control the electromagnetic nonlinear isolator from the high-energy orbit to the low-energy orbit becomes a crucial issue. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide an electromagnetic nonlinear sliding mode active vibration control device and method based on current regulation, so as to realize the electromagnetic nonlinear vibration isolator from high energy track to low energy track, and realize vibration isolation on the low energy track.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An electromagnetic nonlinear sliding mode active vibration control device based on current regulation includes an electromagnetic nonlinear vibration isolator. The electromagnetic nonlinear vibration isolator is connected to the input terminal of a signal acquisition unit via a sensor 1. The output terminal of the signal acquisition unit is connected to the input terminal of a control unit. The output terminal of the control unit is connected to the electromagnetic nonlinear vibration isolator via an execution unit.

[0009] The electromagnetic nonlinear vibration isolator includes a load 2 connected to a sensor 1, the load 2 being connected to a shaft 3; the shaft 3 is connected to a support frame 5 via a sliding bearing 4, an internal electromagnet 6 is connected to the middle of the shaft 3 inside the support frame 5, the internal electromagnet 6 and an external electromagnet 7 fixed inside the support frame 5 cooperate, springs 8 are sleeved on the shaft 3 at both ends of the internal electromagnet 6, the two ends of the springs 8 are connected to the internal electromagnet 6 and the support frame 5, and the internal electromagnet 6, the external electromagnet 7 and the output end of the execution unit are connected.

[0010] The spring 8 generates elastic force to provide positive stiffness, while the internal electromagnet 6 and the external electromagnet 7 generate electromagnetic force to provide negative stiffness. By combining the positive stiffness elastic force and the negative stiffness electromagnetic force, a quasi-zero stiffness vibration isolation system can be obtained. The electromagnetic nonlinear vibration isolator can adjust the electromagnetic force through external current, thereby adjusting the nonlinear stiffness of the quasi-zero stiffness vibration isolation system.

[0011] The sensor 1 is used to monitor the motion trajectory of the electromagnetic nonlinear vibration isolator in real time, including acceleration, velocity, or displacement.

[0012] The control unit performs control operations to compare the real-time trajectory of the electromagnetic nonlinear vibration isolator with the low-energy track trajectory, and then calculates the real-time control signal through a sliding mode control algorithm.

[0013] The execution unit is controlled by the control unit, receives control signals from the control unit, and then controls the current of the electromagnetic nonlinear vibration isolator in real time.

[0014] The control method using the aforementioned current-regulated electromagnetic nonlinear sliding mode active vibration control device includes:

[0015] First, under the given environmental excitation amplitude and frequency, the trajectory of load 2 in the low-energy orbit is measured and stored in the control unit as the desired trajectory.

[0016] Secondly, the trajectory signal of the electromagnetic nonlinear vibration isolator is monitored in real time by sensor 1. If the electromagnetic nonlinear vibration isolator is always in the low-energy track, no control is required. Once the electromagnetic nonlinear vibration isolator is disturbed and enters the high-energy track, the control unit starts sliding mode control. During the control process, the trajectory signal of the electromagnetic nonlinear vibration isolator is compared with the desired trajectory, and the control signal is sent to the execution unit in real time through the sliding mode control algorithm, so that the execution unit adjusts the current, thereby making the trajectory signal of the electromagnetic nonlinear vibration isolator continuously track the desired trajectory.

[0017] Ultimately, sliding mode control enables the electromagnetic nonlinear vibration isolator to change from a high-energy track to a low-energy track. At this point, the sliding mode control ends, and the quasi-zero stiffness vibration isolation system will stabilize in the low-energy track, achieving the vibration isolation effect. Furthermore, if the isolated object is disturbed again and changes to a high-energy track, the sliding mode control process will be triggered again.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] Because this invention uses a sliding mode control algorithm to control the current and thus adjust the electromagnetic force, it has the advantage of changing the electromagnetic nonlinear vibration isolator from a high-energy track to a low-energy track, thereby stabilizing the electromagnetic nonlinear vibration isolator in the low-energy track and achieving a stable vibration isolation effect. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device according to an embodiment of the present invention.

[0021] Figure 2 This is the restoring force curve of electromagnetic nonlinear vibration isolation in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of an electromagnetic nonlinear sliding mode active vibration control method based on current regulation, according to an embodiment of the present invention.

[0023] Figure 4 This is the expected trajectory of the electromagnetic nonlinear vibration isolator in a low-energy track according to an embodiment of the present invention.

[0024] Figure 5 This refers to the displacement of the electromagnetic nonlinear vibration isolator in this embodiment of the invention as it changes from a high-energy track to a low-energy track.

[0025] Figure 6 This refers to the change in transmissivity during the sliding mode control process of the electromagnetic nonlinear vibration isolator in this embodiment of the invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0027] Reference Figure 1 An electromagnetic nonlinear sliding mode active vibration control device based on current regulation includes an electromagnetic nonlinear vibration isolator, a sensor 1, a signal acquisition unit, a control unit, and an execution unit. The electromagnetic nonlinear vibration isolator is connected to the input terminal of the signal acquisition unit through the sensor 1. The output terminal of the signal acquisition unit is connected to the input terminal of the control unit. The output terminal of the control unit is connected to the electromagnetic nonlinear vibration isolator through the execution unit.

[0028] The electromagnetic nonlinear vibration isolator includes a load 2 connected to a sensor 1, the load 2 connected to a shaft 3, forming the object to be isolated; the shaft 3 is connected to a support frame 5 via a sliding bearing 4, which restricts the axial movement of the shaft 3; an internal electromagnet 6 is connected to the middle of the shaft 3 inside the support frame 5, the internal electromagnet 6 cooperates with an external electromagnet 7 fixed inside the support frame 5, the support frame 5 is the excitation loading position, springs 8 are sleeved on the shaft 3 at both ends of the internal electromagnet 6, the two ends of the springs 8 are connected to the internal electromagnet 6 and the support frame 5, and the springs 8 generate elastic force to provide positive stiffness; the internal electromagnet 6, the external electromagnet 7 are connected to the output end of the execution unit, and the internal electromagnet 6 and the external electromagnet 7 generate electromagnetic force to provide negative stiffness.

[0029] By combining positive stiffness elastic force and negative stiffness electromagnetic force, a quasi-zero stiffness vibration isolation system can be obtained, and its restoring force curve is shown below. Figure 2 As shown, it can be seen that the dynamic stiffness of the quasi-zero stiffness vibration isolation system is relatively small near the equilibrium point; while the static stiffness of the quasi-zero stiffness vibration isolation system is relatively large in the region far from the equilibrium position. Therefore, electromagnetic nonlinear vibration isolators can simultaneously meet the requirements of high support capacity and low natural frequency, and have better vibration isolation performance than linear vibration isolators; however, from Figure 2 It can be seen that the restoring force curve of the electromagnetic nonlinear vibration isolator has nonlinear characteristics, which leads to the generation of multiple solution regions under large amplitude excitation conditions, including high-energy tracks and low-energy tracks. Due to the existence of unstable factors such as interference during the operation of the electromagnetic nonlinear vibration isolator, it is easy for the electromagnetic nonlinear vibration isolator to be in the high-energy track, resulting in amplification of excitation vibration. Therefore, it is necessary to use the control method of this invention to change the electromagnetic nonlinear vibration isolator from the high-energy track to the low-energy track.

[0030] The sensor 1 is used to monitor the motion trajectory of the electromagnetic nonlinear vibration isolator in real time, including acceleration, velocity or displacement.

[0031] The signal acquisition unit performs signal acquisition operations to acquire signals from monitoring sensor 1 and transmit them to the control unit;

[0032] The control unit performs control operations to compare the real-time trajectory of the electromagnetic nonlinear vibration isolator with the low-energy track trajectory, and then calculates the real-time control signal through a sliding mode control algorithm.

[0033] The execution unit is controlled by the control unit, receives control signals from the control unit, and then controls the current of the electromagnetic nonlinear vibration isolator in real time.

[0034] Reference Figure 3 , Figure 3 This is a schematic diagram of the electromagnetic nonlinear sliding mode active vibration control method based on current regulation in this embodiment. The control method using the electromagnetic nonlinear sliding mode active vibration control device based on current regulation includes:

[0035] First, under the given environmental vibration excitation frequency and amplitude, the trajectory of the electromagnetic nonlinear vibration isolator in the low-energy track state is measured, which can be acceleration, velocity or displacement. The trajectory of the low-energy track is stored in the controller as the desired trajectory.

[0036] Secondly, when the electromagnetic nonlinear vibration isolator operates under given environmental excitation amplitude and frequency conditions, the displacement of the load 2 is monitored in real time by sensor 1, and then transmitted to the control unit through the signal acquisition unit. The displacement is compared with that of the low-energy track in the control unit. Once subjected to external disturbance, sensor 1 will monitor the displacement signal of the load 2 in real time and compare it with the displacement of the low-energy track in the control unit. Then, the current control signal is calculated by error tracking of the sliding mode control algorithm. After the execution unit receives the current control signal, it will quickly adjust the current of the internal electromagnet 6 and the external electromagnet 7. Subsequently, the electromagnetic force in the quasi-zero stiffness vibration isolation system will change, thereby adjusting the quasi-zero stiffness vibration isolation system from the high-energy track to the low-energy track through variable stiffness, and ending the sliding mode control so that the electromagnetic nonlinear vibration isolator remains stable in the low-energy track.

[0037] pass Figure 3 It can be seen that the displacement amplitude of the high-energy track is much greater than that of the low-energy track. Therefore, by changing the electromagnetic nonlinear vibration isolator from the high-energy track to the low-energy track based on the present invention, the vibration amplitude can be greatly reduced, thus achieving the vibration isolation effect.

[0038] Combining Figures 4-6 This embodiment describes the displacement change of the electromagnetic nonlinear vibration isolator in the control method. Figure 4 The expected trajectory of the electromagnetic nonlinear vibration isolator on the low-energy track is used as the desired trajectory of the vibration isolator and stored in the control unit. Figure 5 To illustrate the displacement change process of the electromagnetic nonlinear vibration isolator from a high-energy track to a low-energy track in this embodiment, during the initial 0-3s period, the electromagnetic nonlinear vibration isolator remains in the high-energy track, showing a large displacement amplitude. From 3-6s, the method of this invention begins to actively control the electromagnetic nonlinear vibration isolator, adjusting the current of the electromagnet through sliding mode control to gradually change the electromagnetic nonlinear vibration isolator from the high-energy track to the low-energy track, and the displacement gradually decreases. At 6s, the sliding mode control ends, and the electromagnetic nonlinear vibration isolator remains in the low-energy track state.

[0039] Figure 6The transmissivity variation in the sliding mode control method for electromagnetic nonlinear vibration isolators clearly reflects the contribution of the method to vibration isolation performance. In the high-energy track region of 0-3s, the transmissivity can reach about 20dB, and the electromagnetic nonlinear vibration isolator cannot play a vibration isolation role. After a control process of 3-6s, the low-energy track region is reached. In the low-energy track region of 6-10s, the transmissivity is about -4dB, and the electromagnetic nonlinear vibration isolator can play a vibration isolation role.

[0040] The beneficial effects of this embodiment are: Through Figure 1 and Figure 5 It can be seen that when the nonlinear electromagnetic vibration isolation system is in a high-energy orbit due to external interference and other factors under large-amplitude excitation, the system response amplitude is large. Therefore, based on devices such as sensors, signal acquisition units, control units, execution units and electromagnets, the nonlinear sliding mode active control method of the present invention is used to control the electromagnet current, so that the vibration isolation system gradually approaches the low-energy orbit during the control process, and stabilizes in the low-energy orbit after the control ends, thereby achieving the vibration isolation effect.

Claims

1. An electromagnetic nonlinear sliding mode active vibration control device based on current regulation, comprising an electromagnetic nonlinear vibration isolator, characterized in that: The electromagnetic nonlinear vibration isolator is connected to the input terminal of the signal acquisition unit via the sensor (1), the output terminal of the signal acquisition unit is connected to the input terminal of the control unit, and the output terminal of the control unit is connected to the electromagnetic nonlinear vibration isolator via the execution unit; The electromagnetic nonlinear vibration isolator includes a load (2) connected to a sensor (1), the load (2) being connected to a shaft (3); the shaft (3) is connected to a support frame (5) via a sliding bearing (4), an internal electromagnet (6) is connected to the middle of the shaft (3) inside the support frame (5), the internal electromagnet (6) and an external electromagnet (7) fixed inside the support frame (5) cooperate, springs (8) are sleeved on the shaft (3) at both ends of the internal electromagnet (6), the two ends of the springs (8) are connected to the internal electromagnet (6) and the support frame (5), and the internal electromagnet (6), the external electromagnet (7) and the output end of the execution unit are connected; The spring (8) generates elastic force to provide positive stiffness, and the internal electromagnet (6) and external electromagnet (7) generate electromagnetic force to provide negative stiffness. By combining the positive stiffness elastic force and the negative stiffness electromagnetic force, a quasi-zero stiffness vibration isolation system can be obtained. The electromagnetic nonlinear vibration isolator can adjust the electromagnetic force through external current, thereby adjusting the nonlinear stiffness of the quasi-zero stiffness vibration isolation system. The control unit performs control operations to compare the real-time trajectory of the electromagnetic nonlinear vibration isolator with the low-energy track trajectory, and then calculates the real-time control signal through a sliding mode control algorithm. The sensor (1) is used to monitor the motion trajectory of the electromagnetic nonlinear vibration isolator in real time, including acceleration, velocity or displacement; The execution unit is controlled by the control unit, receives control signals from the control unit, and then controls the current of the electromagnetic nonlinear vibration isolator in real time. Under the given environmental excitation amplitude and frequency, the trajectory of the load (2) in the low-energy track is measured and stored in the control unit as the desired trajectory; the trajectory signal of the electromagnetic nonlinear vibration isolator is monitored in real time by the sensor (1). If the electromagnetic nonlinear vibration isolator is always in the low-energy track, there is no need to control it; once the electromagnetic nonlinear vibration isolator is disturbed and in the high-energy track, the control unit starts to perform sliding mode control; during the control process, the trajectory signal of the electromagnetic nonlinear vibration isolator is compared with the desired trajectory, and the control signal is sent to the execution unit in real time through the sliding mode control algorithm, so that the execution unit adjusts the current, thereby making the trajectory signal of the electromagnetic nonlinear vibration isolator continuously track the desired trajectory; Sliding mode control enables the electromagnetic nonlinear vibration isolator to change from a high-energy track to a low-energy track. At this point, the sliding mode control ends, and the quasi-zero stiffness vibration isolation system will stabilize in the low-energy track, achieving the vibration isolation effect. Once the isolated object is disturbed again and changes to a high-energy track, the sliding mode control process will be triggered again.

2. The control method using the device according to claim 1, characterized in that, include: First, under the given environmental excitation amplitude and frequency, the trajectory of the load (2) in the low-energy orbit is measured and stored in the control unit as the desired trajectory; Secondly, the trajectory signal of the electromagnetic nonlinear vibration isolator is monitored in real time by the sensor (1). The electromagnetic nonlinear vibration isolator is always in the low-energy track, so there is no need to control it. Once the electromagnetic nonlinear vibration isolator is disturbed and is in the high-energy track, the control unit starts to perform sliding mode control. During the control process, the trajectory signal of the electromagnetic nonlinear vibration isolator will be compared with the desired trajectory, and the control signal will be sent to the execution unit in real time through the sliding mode control algorithm, so that the execution unit adjusts the current, thereby making the trajectory signal of the electromagnetic nonlinear vibration isolator continuously track the desired trajectory. Ultimately, sliding mode control enables the electromagnetic nonlinear vibration isolator to change from a high-energy track to a low-energy track. At this point, the sliding mode control ends, and the quasi-zero stiffness vibration isolation system will stabilize in the low-energy track, achieving the vibration isolation effect. Once the isolated object is disturbed again and changes to a high-energy track, the sliding mode control process will be triggered again.

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