JP2009275828A - Vibration damping device and manufacturing method of excitation command table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To limit to a proper range the vibration amplitude of a vibration damping device which suppresses vibration using the resonance of auxiliary mass at a certain frequency. <P>SOLUTION: The vibration damping device includes: an actuator 13, which gives a reaction force to a vibration control object by vibrating the auxiliary mass supported by the vibration control object via a spring element; and a control section, which damps the vibration of the vibration control object by controlling the amplitude and frequency of a driving current supplied to the actuator. A current upper limit table 23, which restricts the amplitude of the driving current supplied to the actuator, is provided on this damping device. The current upper limit table defines the upper limit of the amplitude of a current command value in advance based on frequency characteristics of a transmission function that shows the relation of the current command value that controls the driving current to the acceleration of the auxiliary mass and the permissible maximum displacement of the auxiliary mass. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration damping device that performs vibration suppression control of a vibration damping target device such as an automobile and a method of manufacturing a current upper limit table used in the vibration damping device.

  Conventionally, focusing on the fact that the vehicle vibration caused by the output torque fluctuation of the vehicle engine corresponds to the engine speed, the actuator is driven to cancel the body vibration that is predicted to occur by detecting the engine speed. A vibration control device that reduces vehicle vibration is known (for example, see Patent Document 1). According to this apparatus, the control circuit cancels out the vehicle body vibration and the reaction force generated by the reciprocating vibration means by referring to a pre-stored table according to the engine speed. The generated command signal is output. And it is said that the vibration of the vehicle body can be reduced by driving the actuator with this command signal.

  On the other hand, a linear actuator in which a movable element is supported by an elastic support portion (plate spring) so as to be able to reciprocate with respect to a stator is known as a vibrating means for performing reciprocating movement (for example, Patent Documents). 2). Since this linear actuator does not wear the mover, the accuracy of shaft support does not deteriorate even after long-term use. Also, since sliding resistance does not act on the mover, power loss due to sliding resistance is small. Furthermore, since the bulky coil and the elastic support portion can be arranged close to each other, the linear actuator can be miniaturized.

The linear actuator described in Patent Document 2 can cancel the vibration generated by the target device to be controlled by the reaction force during driving. That is, by applying a current command so that the reaction force generated by the actuator has an opposite phase with respect to the vibration acceleration of the vibration suppression target device, the actuator can reduce the vibration of the vibration suppression target device. By attaching a vibration damping device using such a linear actuator to the vehicle body, the force applied to the vehicle body from the engine of the vehicle can be offset, so that vibration of the vehicle body can be reduced.
JP-A-61-220925 JP 2004-343964 A

  By the way, an actuator used in such a vibration damping device is generally provided with an auxiliary mass (weight) on the mover in order to increase the reaction force. Also, in order to increase the damping efficiency, the resonance frequency of the mechanical system composed of the actuator mover and auxiliary mass and the elastic support portion is often matched with the frequency to be damped. That is, even when an actuator with a small generated thrust is used, the generated reaction force can be increased by utilizing the resonance, so that the large acceleration vibration generated by the vibration generating source can be suppressed.

However, when the above-described vibration damping device is used, for example, for improving the riding comfort of an automobile, there is a problem that the actuator is damaged because the movable element vibrates beyond the allowable amplitude due to resonance. The reason is described below.
Since the vibration characteristics of the automobile are determined by the engine speed, the control unit of the vibration damping device calculates and outputs a current command to the actuator, that is, the current amplitude and frequency, according to the engine speed. Further, the mechanical system described above has the highest gain at the resonance frequency when considering the transfer characteristics from the command current to the actuator to the amplitude of the mover, and the gain becomes smaller as the frequency becomes higher than the resonance frequency. Therefore, for example, when the engine rotation frequency at idling matches the resonance frequency of the vehicle body frame, the resonance frequency of the mechanical system of the actuator matches the resonance frequency of the vehicle body frame for the reason described above.
Here, when traveling at a high engine rotation frequency, the actuator operates at a frequency higher than the resonance frequency of the mechanical system, so that a large current command is required to obtain a reaction force required for damping. That is, in order to obtain the required reaction force, the displacement amplitude of the mover must be greater than a certain value. However, the higher the actuator drive frequency, the smaller the displacement amplitude of the mover that can be generated with the same current amplitude. A large current amplitude is required to obtain the displacement amplitude.
On the other hand, the engine speed of a car fluctuates greatly by simply stepping on or loosening the accelerator regardless of whether it is running or stopped. For this reason, for example, when the engine suddenly changes to an idling state due to a sudden stop of the vehicle, the transient state causes the mechanical system to change to a resonance state with a large current amplitude at non-resonance, so the actuator mover has an excessive displacement amplitude. It will vibrate. At this time, the auxiliary mass applied to the mover collides with the body frame, the stopper of the actuator, or the like, and the elastic support portion is displaced beyond the elastic limit, so that the actuator is damaged.
In addition, when the mover vibrates with an excessive displacement amplitude, the actuator is not vibrated, but is in a vibrating state, which causes the ride quality of the automobile to deteriorate.
Note that the above phenomenon occurs in a vibration damping device using an actuator that increases the generated reaction force using resonance of a mechanical system regardless of whether the automobile is in an idling state or a traveling state.

  The present invention has been made in view of such circumstances, and provides a vibration damping device that can prevent damage to the actuator and obtain a stable vibration damping effect even when the frequency of the vibration source changes. For the purpose.

The present invention comprises a movable member that is provided at a position to be damped by a fixed member and is supported by an elastic member so that the fixed member can reciprocate in the vibration direction of the damped object. And a control unit that outputs a vibration command for generating a vibration control force that cancels the vibration at the position to be controlled to the vibration control unit based on the vibration of the vibration control target. The vibration control device, wherein the control unit determines a limit value of the vibration command for each frequency based on a transmission characteristic from the vibration command to a relative state quantity of the movable member with respect to the fixed member. An upper limit table is provided.
The state quantity indicates a physical quantity that changes with time, such as force, acceleration, speed, and displacement. The limit value of the excitation command means the upper limit value of the excitation command amplitude.
With the above configuration, the vibration command input to the vibration means can be limited by the upper limit value determined for each frequency based on the transfer function from the vibration command to a relatively large amount of the movable member relative to the fixed member. Even if the frequency of vibration of the target changes suddenly, it is possible to prevent the fixing member of the vibration means from vibrating excessively. For this reason, it is possible to prevent the vibration control means from being damaged due to excessive vibrations or damage to the vibration suppression target due to the movable member colliding with the vibration suppression target.

The excitation command upper limit table of the present invention is characterized in that the excitation command near a resonance frequency of a mechanical system including at least the elastic member and the movable member is limited.
Note that the vicinity of the resonance frequency indicates a range from 1/10 times the resonance frequency to 10 times the frequency.
With the above configuration, since the vibration command near the resonance frequency of the mechanical system consisting of the elastic member and the movable part can be limited, the resonance frequency of the vibration control object and the resonance frequency of the mechanical system are matched, and the control object is the non-resonance frequency. Even when the driving state is changed from the driving state to the driving state at the resonance frequency, it is possible to prevent the movable member of the vibration means from vibrating excessively.

Further, the limit value of the present invention is a value obtained by dividing the product of the maximum value of the relative displacement and the square of the frequency by a transfer function from the excitation command to the relative acceleration of the movable member with respect to the fixed member. It is characterized by being.
The maximum value of the relative displacement indicates the maximum amount of displacement that the movable member can move with respect to the fixed member of the vibration means.
With the above configuration, the current upper limit table can be created by obtaining the allowable drive current in advance from the allowable maximum displacement, frequency, and transfer function.

In addition, the present invention provides a movable member supported by an elastic member so that the fixed member is provided at a position to be controlled by the vibration suppression target and can reciprocate in the vibration direction of the vibration suppression target with respect to the fixed member. And a control unit for outputting a vibration command for generating a vibration control force for canceling vibration at the position to be controlled by the vibration control means based on the vibration of the vibration control target. And the control unit outputs a vibration command output to the vibration means for a vibration command upper limit table manufacturing method used in a vibration damping device that limits the vibration command based on a predetermined vibration command upper limit table. Based on the process of measuring the transfer characteristics from the excitation command to the relative displacement of the movable member with respect to the fixed member, the transfer function measured by the process and the maximum value of the relative displacement, Relationship with vibration command And having a process of generating a vibration command upper table by determining the.
With the above configuration, the allowable current command value for each vibration frequency is obtained using the allowable maximum displacement, the drive frequency of the actuator, and the transfer function from the drive current command value of the actuator to the acceleration of the auxiliary mass. The current upper limit table can be created.

  According to the present invention, the control unit limits the amplitude of the vibration command by referring to the vibration command upper limit table so that the actuator mover does not exceed the preset allowable displacement amplitude. Even when the frequency of the actuator changes, it is possible to prevent the actuator from being damaged.

<First Embodiment>
Hereinafter, a vibration damping device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. Reference numeral 1 denotes an excitation unit installed in the control target device 4 that is the target of vibration suppression. The control target device 4 is, for example, a car body frame, a seat, an engine, or the like. The vibration unit 1 is a linear actuator shown in Patent Document 2, and is hereinafter referred to as a reciprocating motor.

  The mover 13 of the reciprocating motor is supported by the stator 12 via the leaf spring 14 and the shaft 13, and reciprocates with respect to the stator 12. The stator 12 includes a permanent magnet and a coil (not shown), and the control target device is configured such that the vibration direction (vertical direction in FIG. 1) of the control target device 4 to be damped matches the vibration direction of the mover 12. 4 is fixed. In FIG. 1, the movable element 13 vibrates in the vertical direction similarly to the control target device 4, so that the reaction force acting on the control target device 4 suppresses the vibration of the control target device 4. The stopper 16 limits the upper and lower movable ranges of the mover 13. The auxiliary mass 11 is a weight for increasing the reaction force acting on the control target device 4. The natural frequency of the mechanical system determined by the mass including the mover 12, the shaft 13, and the auxiliary mass 11 and the spring constant of the leaf spring 14 matches the natural frequency of the primary mode of the control target device 4. Thus, it is adjusted by the mass and spring constant. In the following description, the mover 12, the shaft 13, and the auxiliary mass 11 are referred to as a movable part.

  The command value generation unit 20 receives state values such as the engine speed of the control target device 4 and calculates and outputs a reciprocating motor vibration command, that is, a current amplitude and frequency command value. The current upper limit clamp table 23 is a table in which the upper limit value of the current amplitude is stored in advance for each frequency, and the frequency command value is input and the upper limit value of the amplitude command value is output. Details of this upper limit will be described later. The applied current generator 22 receives the frequency command value, the amplitude command value, and the upper limit value of the amplitude command value, and outputs the applied current command value. This applied current command value is a command value in which the amplitude of the current is limited so that the movable part of the reciprocating motor is in an appropriate movable range for each drive frequency. The power amplifier 3 receives an applied current command value, amplifies and outputs a current to be passed through a coil (not shown) provided in the stator 12.

  Next, the operation of the vibration unit 1 shown in FIG. 1 will be described. When no current is passed through the coil of the reciprocating motor (not shown), the magnetic flux generated by the permanent magnet provided in the stator 12 passes from the left N pole of the stator 12 to the left S pole and the right S pole. Further, the movable element 13 is held at the magnetic center position as shown in FIG. 1 by passing from the right north pole of the stator 12 to the right south pole and the left south pole. Here, when a current is passed through a coil (not shown) so that a magnetic flux is generated from the left side to the right side of the stator 12, the magnetic flux passing from the left N pole of the stator 12 to the right S pole is strengthened, and the right side When the magnetic flux passing from the north pole to the left south pole is weakened, the mover 13 moves in the upward direction of the arrow. On the other hand, when a current is passed through a coil (not shown) so that magnetic flux is generated from the right side to the left side of the stator 12, the magnetic flux passing from the right north pole of the stator 12 to the left south pole is strengthened, and the left side N When the magnetic flux passing from the pole to the right S pole is weakened, the mover 13 moves in the downward direction of the arrow. That is, when an alternating current is passed through a coil (not shown), the movable element 13, that is, the movable part vibrates in the vertical direction.

  Here, the natural frequency of the mechanical system composed of the movable part of the reciprocating motor and the leaf spring is adjusted to coincide with the natural frequency of the primary mode of the control target device 4 as described above. Therefore, for example, when the control target device 4 vibrates at the natural frequency of the secondary mode, the vibration damping device detects the state value of the control target device 4 and the vibration unit 1 detects that the vibration target device 4 An excitation command is generated and output so as to vibrate in the opposite phase to the vibration in the next mode. In this case, since the frequency of the secondary mode is higher than that of the primary mode, the movable part can obtain the reaction force F in order for the vibration part 1 to apply the reaction force F necessary for the control target device 4. It is necessary to vibrate with a displacement amplitude of. However, if the vibration frequency of the device 4 to be controlled suddenly changes while the vibration control device is controlling the secondary mode, the device 4 to be controlled vibrates in the primary mode. Then, since the mechanical system of the excitation unit 1 resonates at the frequency of the primary mode with a large current amplitude at the time of non-resonance, the movable unit vibrates with an excessive displacement amplitude. Then, since the movable element 13 collides with the stopper 16, the movable part collides with the device to be controlled, or the leaf spring 14 is deformed beyond the elastic limit, the vibration part 1 may be damaged.

  Therefore, since the current upper limit clamp table 23 limits the upper limit of the current amplitude of the applied current command value in accordance with the change of the frequency command value, the movable part is prevented from vibrating with an excessive displacement amplitude even in a transient state. it can. Further, since the applied current command value is corrected by referring to the table, the amount of calculation in the applied current generation unit 22 can be reduced. That is, the processing speed can be increased and an inexpensive arithmetic unit can be used, so that the cost can be reduced.

Here, the current upper limit clamp table will be described with reference to FIG.
Assuming that the vibration of the movable part can be approximated by a sinusoidal wave having an acceleration amplitude A _p and an angular frequency ω, since the acceleration a is a = A _p sinωt, the displacement x is x = (− A _P / ω ² ) sinωt. It is represented by That is, the maximum amplitude L _p of the displacement x is L _p = A _P / ω ² . The _{L p} determines the upper limit value of the amplitude of the two so that less than half the interval 2L _s stopper 16 _(L p <L _s) current command.

If the current command is defined as I _ref = I _p · sin ωt, the transfer function G from the current command I _ref to the acceleration a of the movable part is represented by G = a / I _ref . Where _{a = A p sinωt = (-} L p · ω 2) · sinωt, from the relation of ω = 2πf, G = (- L p · ω 2) · sinωt / (I p · sinωt) = (- L p Ω ² ) / I _p = (− L _p ) · (2πf) ² / I _p

That is, from I _p = (− L _p ) · (2πf) ² / G, the current amplitude is calculated from the maximum amplitude L _p of the displacement x, the vibration frequency f of the movable part, and the transfer function G from the current command to the acceleration. limit _{I p} can be obtained.

Here, the maximum amplitude L _p of the displacement x is a value that can be obtained in advance from the allowable maximum displacement of the movable part and the elastic limit range of the leaf spring 14, and the vibration frequency f of the movable part is a control object to be detected as a state value. This value is obtained from the vibration frequency of the device. Further, the transfer function G can be obtained experimentally by a transfer function measuring device with the configuration of FIG. In FIG. 2, reference numeral 51 denotes an acceleration sensor for detecting acceleration in the vibration direction of the movable part.
As described above, the current upper limit clamp table 23 is a table in which the upper limit value I _{p of the} current amplitude obtained from the maximum amplitude L _p of the displacement x with respect to the frequency f and the transfer function G is stored, and the frequency command value is input. Then, the upper limit value _Ip of the current amplitude can be output to the applied current generation unit.

As mentioned above, although one Embodiment of this invention was described, it is not restricted to this.
For example, it is not an essential condition of the present invention that the excitation unit 1 is a reciprocating promoter. That is, the vibration unit 1 may be an actuator that can move the movable unit relative to the fixed unit to apply a reaction force to the control target device 4. For example, the vibration unit 1 may be a voice coil motor or a solenoid. Or a motor that operates on a principle other than magnetism, such as a piezo actuator using a piezoelectric element.
Further, the fixed member and the movable member of the vibration unit 1 do not necessarily need to coincide with the stator and the movable member of the actuator. That is, in this embodiment, a stator 12 having a permanent magnet and a coil (not shown) is used as a fixed member, and a movable portion including the mover 13, the shaft 15, and the auxiliary mass 11 is used as a movable member. Conversely, the movable member 13 may be fixed to the control target device 4 via the shaft 15, and the stationary member 12 movable relative to the movable member 13 may be used as the movable member. By adopting such a configuration, the stator 12 main body, the permanent magnet, and a coil (not shown) can be used as the mass of the movable member. Therefore, it is not necessary to separately provide the auxiliary mass 11 for increasing the reaction force as in the present embodiment, so that the vibration unit 1 can be made compact and the cost can be reduced.
In the present embodiment, the engine speed is detected as the state value of the control target device 4, but other signals that can correspond to the vibration frequency of the control target device to be suppressed may be used. For example, another state value that can be output by the control target device 4 such as an engine ignition timing signal may be detected, or the state value may be detected by installing a detector such as an acceleration sensor in the control target device 4. good.
Further, the current upper limit clamp table 23 may be a table in which the upper limit value I _p of the current amplitude is stored for at least some frequency bands. That is, for example, the upper limit of the current amplitude may be limited only in the vicinity of the resonance frequency of the mechanical system of the actuator, and the current amplitude may not be limited for other frequency bands.
Other configurations can be variously modified without departing from the gist of the present invention.

It is a block diagram which shows the structure of 1st Embodiment of this invention. It is a block diagram of the system used for the production | generation of the electric current upper limit clamp table of FIG.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Excitation part, 11 ... Auxiliary mass (weight), 12 ... Reciprocating motor (stator), 13 ... Reciprocating motor (moving element), 14 ... Leaf spring, 15 ... Axis, 16 ... stopper, 20 ... command value generator, 22 ... applied current generator, 23 ... current upper limit clamp table, 50 ... transfer function measuring instrument

Claims (4)

Excitation means comprising a movable member supported by an elastic member so that the fixed member is provided at a position to be damped of the object to be damped, and can reciprocate in the vibration direction of the object to be damped. When,
A vibration control device comprising: a control unit that outputs a vibration command to generate vibration control force that cancels vibration at the position to be controlled in the vibration control unit based on the vibration of the vibration control target; There,
The control unit includes an excitation command upper limit table that defines a limit value of the excitation command for each frequency based on a transmission characteristic from the excitation command to a relative state quantity of the movable member with respect to the fixed member. A vibration damping device characterized by that.   2. The vibration damping device according to claim 1, wherein the vibration command upper limit table limits the vibration command near a resonance frequency of a mechanical system including at least the elastic member and the movable member.   The limit value is a value obtained by dividing the product of the maximum value of the relative displacement that is the relative state quantity and the square of the frequency by a transfer function from the excitation command to the relative acceleration of the movable member with respect to the fixed member. The vibration damping device according to claim 1, wherein: Excitation means comprising a movable member supported by an elastic member so that the fixed member is provided at a position to be damped of the object to be damped, and can reciprocate in the vibration direction of the object to be damped. When,
A control unit that outputs a vibration command for generating a vibration control force that cancels the vibration at the position to be controlled in the vibration control unit based on the vibration of the vibration control target;
The control unit, based on a predetermined vibration command upper limit table, for a vibration command upper limit table manufacturing method used in a vibration damping device that limits the vibration command,
A step of measuring a transmission characteristic from the vibration command output to the vibration means to the relative state quantity of the movable member with respect to the fixed member;
A step of generating an excitation command upper limit table by obtaining a relationship between the frequency and the excitation command based on the transfer function measured by the process and the maximum value of the relative displacement. A method for manufacturing the vibration command table.

Images