An inertial actuator with virtual mass

Abstract

The invention discloses an inertial actuator with virtual mass, which comprises an inertial actuator and a control module; the inertial actuator comprises a lower end bottom plate, a support beam, a coil, a permanent magnet and a thin spring steel bar; the coil is fixed on the upper part of the lower end bottom plate, the permanent magnet is fixed on the lower part of the thin spring steel bar, and the thin spring steel bar is arranged above the lower end bottom plate; the thin spring steel bar and the lower end bottom plate are connected by the support beam; the control module comprises an acceleration sensor, a signal amplification circuit and a power amplification circuit; the acceleration sensor is arranged in the middle part of the thin spring steel bar, and the acceleration sensor, the signal amplification circuit, the power amplifier and the coil are connected in series to form a complete loop; the invention can increase the virtual mass of the inertial actuator by adjusting the gain of the signal amplification circuit without increasing the size and physical mass of the inertial actuator, thereby reducing its natural frequency, and has fast response and high reliability.

Description

Technical Field

[0001] The invention relates to a structural vibration control technology, and in particular to an inertial actuator with virtual mass. Background Art

[0002] Inertial actuators are widely used as actuators in vibration control in the fields of mechanical engineering, aerospace, and transportation due to their simple structure, relatively low price, and easy implementation. They have now become one of the important means of controlling vibration.

[0003] Inertial actuators can generate control force in the vibration direction of the controlled structure without additional support. Typical inertial actuators include electromagnetic, electric and piezoelectric.

[0004] The mass of the inertial actuator has an important influence on the structural vibration control effect. The larger the mass, the lower the natural frequency, and the better the low-frequency control effect on the controlled structure. However, the increase in the mass of the inertial actuator will increase its size and may change the dynamic characteristics of the controlled structure.

[0005] However, the current inertial actuator generally reduces its natural frequency by reducing the stiffness. For example, in the invention patent application with application number 201611203638.0, the stiffness of the inertial actuator is reduced by adding a supporting component to increase the low-frequency output of the inertial actuator. F. Braghin et al. (A low frequency magnetostrictive inertialactuator for vibration control. Sensor and Actuator A: Physical. 2012, 180: 67-74) reduced the natural frequency of the inertial actuator from 1260Hz to 167Hz by increasing the number of permanent magnets and optimizing the spring design.

[0006] The current design for reducing the natural frequency of the inertial actuator has the disadvantages of complex structure, inconvenient use and large size. Summary of the invention

[0007] The object of the present invention is to provide an inertial actuator with a simple structure and increased virtual mass through a feedback control circuit in view of the defects and shortcomings of the prior art.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: it comprises an inertial actuator and a control module;

[0009] The inertial actuator comprises a lower bottom plate, a support beam, a coil, a permanent magnet and a thin spring steel strip; the coil is fixed to the upper part of the lower bottom plate, the permanent magnet is fixed to the lower part of the thin spring steel strip, and the thin spring steel strip is arranged above the lower bottom plate; the thin spring steel strip and the two sides of the lower bottom plate are fixedly connected to each other by two support beams;

[0010] The control module comprises an acceleration sensor, a signal amplifying circuit and a power amplifying circuit; the acceleration sensor is arranged at the center of the thin spring steel strip and connected to the input end of the signal amplifying circuit, the output end of the signal amplifying circuit is connected to the input end of the power amplifier, and the output end of the power amplifier is connected to the coil to form a complete loop.

[0011] Further, the two ends of the support beam are fixed to the thin spring steel strip and the bottom plate at the lower end by welding or by bolts;

[0012] Furthermore, the coil is in an annular structure as a whole, the permanent magnet is in a cylindrical structure as a whole, and the inner diameter of the coil is greater than the outer diameter of the permanent magnet;

[0013] Further, the axes of the coil and the permanent magnet coincide with each other;

[0014] Further, the acceleration sensor is bonded and connected to the thin spring steel strip;

[0015] Furthermore, the cross section of the thin spring steel strip is rectangular.

[0016] The working principle of the present invention is as follows: the inertial actuator with virtual mass described in the present invention is installed on the actuated structure, an alternating current is passed through the coil, when the magnetic field force is greater than the restoring force of the thin spring steel bar, the permanent magnet overcomes the restoring force of the thin spring steel bar and moves in the direction of the magnetic field force, and when the magnetic field force is less than the restoring force of the thin spring steel bar, the thin spring steel bar will pull the permanent magnet back, so that the permanent magnet makes a reciprocating linear motion, thereby generating an inertial force; at the same time, when the actuated structure vibrates under the action of the inertial force, the external vibration signal is transmitted to the thin spring steel bar through the lower end bottom plate and the support beam, and is input into the coil through the acceleration sensor arranged on the thin spring steel bar through the signal amplification circuit and the power amplification circuit, and the size of the inertial force of the permanent magnet can be changed by adjusting the gain of the signal amplification circuit, so as to achieve the effect of changing the equivalent mass of the permanent magnet.

[0017] After adopting the above structure, the beneficial effect of the present invention is as follows: the inertial actuator with virtual mass described in the present invention can increase the virtual mass of the inertial actuator by adjusting the gain of the signal amplification circuit without increasing the size and physical mass of the inertial actuator, thereby reducing its natural frequency, responding quickly, and having high reliability, and has the advantages of simple structure, reasonable setting, and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] Figure 2 is a vibration model diagram of the present invention;

[0021] Figure 3 It is a virtual mass analogy diagram of the present invention.

[0022] Explanation of the reference numerals: 1. lower base plate; 2. support beam; 3. coil; 4. permanent magnet; 5. thin spring steel strip; 6. acceleration sensor; 7. signal amplification circuit; 8. power amplification circuit. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] The technical solution adopted in this specific implementation is: Figure 1 As shown, it includes an inertial actuator and a control module; the inertial actuator includes a lower end bottom plate, a support beam, a coil, a permanent magnet and a thin spring steel bar; the coil is fixed on the upper part of the lower end bottom plate, the permanent magnet is fixed on the lower part of the thin spring steel bar, the coil is a circular ring structure as a whole, the permanent magnet is a cylindrical structure as a whole, the inner diameter of the coil is greater than the outer diameter of the permanent magnet, and the axes of the coil and the permanent magnet coincide with each other; the cross section of the thin spring steel bar is a rectangle; the thin spring steel bar is arranged above the lower end bottom plate; two support beams are respectively arranged on both sides of the thin spring steel bar and the lower end bottom plate; the two ends of the support beam are fixed to the thin spring steel bar and the lower end bottom plate by welding; the control module includes an acceleration sensor, a signal amplification circuit and a power amplification circuit; the acceleration sensor is bonded to the center position of the thin spring steel bar and is connected to the input end of the signal amplification circuit, the output end of the signal amplification circuit is connected to the input end of the power amplifier, and the output end of the power amplifier is connected to the coil to form a complete loop.

[0025] In this specific implementation, the resistance of the coil is between 4 ohms and 8 ohms, and the power of the power amplifier circuit is between 2 watts and 20 watts;

[0026] The working principle of the inertial actuator with virtual mass described in this specific embodiment is as follows: the inertial actuator with virtual mass is installed on the actuated structure, and an alternating current is passed through the coil. When the magnetic field force is greater than the restoring force of the thin spring steel bar, the permanent magnet overcomes the restoring force of the spring sheet and moves in the direction of the magnetic field force. When the magnetic field force is less than the restoring force of the thin spring steel bar, the thin spring steel bar will pull the permanent magnet back, so that the permanent magnet performs a reciprocating linear motion, thereby generating an inertial force. At the same time, when the actuated structure vibrates under the action of the inertial force, the external vibration signal is transmitted to the thin spring steel bar through the lower bottom plate and the support beam, and is input to the coil through the acceleration sensor arranged on the thin spring steel bar through the signal amplification circuit and the power amplification circuit. The size of the inertial force of the permanent magnet can be changed by adjusting the gain of the signal amplification circuit, thereby achieving the effect of changing the equivalent mass of the permanent magnet.

[0027] Depend on Figure 2 Combining the principle of mechanical vibration, the vibration equation of the inertial actuator can be expressed as:

[0028] ma+c(vv s )+k(xx s )=F (1)

[0029] In formula (1), m is the sum of the mass of the permanent magnet and the equivalent mass of the thin spring steel strip, c and k are the equivalent damping and equivalent stiffness of the thin spring steel strip, respectively; a, v, x are the acceleration, velocity and displacement of the permanent magnet, respectively; vs and xs are the velocity and displacement of the bottom plate at the lower end; F is the electromagnetic force generated by the voltage generated by the negative feedback control circuit when it is input to the coil, which is proportional to the acceleration a of the permanent magnet and has the opposite direction, that is,

[0030] F=-a·Gain·B (2)

[0031] In formula (2), Gain is the gain of the signal amplifier circuit, and B is the gain of the power amplifier; Gain and B are both real numbers greater than zero;

[0032] Substituting equation (2) into equation (1), we can get

[0033] (m+Gain×B)a+cv+kx=cv s +kx s (3)

[0034] From formula (3), it can be found that Gain×B is equivalent to applying a virtual mass to the inertial actuator, such as Figure 3 As shown, the equivalent mass of the inertial actuator is m+Gain×B, so the natural frequency of the inertial actuator is Obviously, increasing the gain Gain in the negative feedback circuit can increase the equivalent mass of the inertial actuator, thereby reducing the natural frequency of the inertial actuator.

[0035] In this specific implementation, the equivalent mass of the inertial actuator can be changed by adjusting the gain of the signal amplification circuit, which is equivalent to adding a virtual mass to the inertial actuator. No mechanical driving device is required, and the structure is simple.

[0036] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An inertial actuator with virtual mass, characterized in that: It comprises an inertial actuator and a control module; the inertial actuator comprises a lower end bottom plate, a support beam, a coil, a permanent magnet and a thin spring steel bar; the coil is fixed on the upper part of the lower end bottom plate, the permanent magnet is fixed on the lower part of the thin spring steel bar, and the thin spring steel bar is arranged above the lower end bottom plate; the thin spring steel bar and the two sides of the lower end bottom plate are fixedly connected to each other through two support beams; the control module comprises an acceleration sensor, a signal amplification circuit and a power amplification circuit; the acceleration sensor is arranged at the center of the thin spring steel bar and is connected to the input end of the signal amplification circuit, the output end of the signal amplification circuit is connected to the input end of the power amplification circuit, and the output end of the power amplification circuit is connected to the coil to form a complete loop; the two ends of the support beam are fixed to the thin spring steel bar and the lower end bottom plate by welding or bolts; the coil is a circular ring structure as a whole, the permanent magnet is a cylindrical structure as a whole, the inner diameter of the coil is greater than the outer diameter of the permanent magnet; the axis of the coil and the permanent magnet coincide with each other; the acceleration sensor is bonded and connected to the thin spring steel bar; the cross section of the thin spring steel bar is a rectangle.

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