Disclosure of Invention
In order to overcome the defect of the vibration suppression effect of the traditional RLS algorithm under the condition of complex vibration signals, the invention aims to provide a vibration control method, which improves the vibration suppression effect and improves the convergence precision by combining the RLS algorithm and the self-adaptive fuzzy PID algorithm.
In order to achieve the purpose, the invention adopts the following specific technical scheme:
the invention provides a vibration control method, which comprises the following steps:
s1, generating an initial vibration signal through a vibration source;
s2, inputting the initial vibration signal and the expected value to a first vibration controller to perform first vibration control, and calculating a residual error signal;
and S3, outputting the residual error signal to a second vibration controller to perform the second vibration control.
Preferably, the calculation formula of the actual output value y (n) of the first vibration controller is:
y(n)=w(n)Tu(n) (1.8)
wherein u (n) is an initial vibration signal, w (n) is a weight of the first vibration controller, and n is time;
the residual error signal e (n) is calculated by:
e(n)=d(n)-y(n) (1.9)
where d (n) is the desired output value of the first vibration controller.
Preferably, the weight value is updated by the following formula:
w (n) ═ w (n-1) + k (n) e (n) (1.10) where k (n) is the gain vector, which is calculated as:
where λ is the forgetting factor and p (n) is the covariance matrix.
Preferably, the covariance matrix p (n) is calculated as:
preferably, the second vibration controller calculates a residual vibration signal from the residual error signal.
The residual vibration signal is calculated by the formula:
wherein, KP、KI、KDRespectively are the integral proportional coefficients under the fuzzy rule; n is the filter coefficient of the PID controller, TsFor discrete time, 1/S is the time constant after Laplace transform.
Preferably, the calculation formula of the setting proportion coefficient is as follows:
KP0is said KPAn initial value of (1); Δ KPA parameter change value adjusted for the adaptive fuzzy controller;
KI0is said KIAn initial value of (1); Δ KIA parameter change value adjusted for the adaptive fuzzy controller;
KD0is said KDAn initial value of (1); Δ KDA parameter change value adjusted for the adaptive fuzzy controller.
Preferably, the first vibration controller is a vibration active controller based on the RLS algorithm.
Preferably, the second vibration controller is an active controller that self-tunes the PID parameters based on a fuzzy algorithm and is combined as an adaptive fuzzy P, adaptive fuzzy PD or adaptive fuzzy PI controller.
Preferably, the initial vibration signal is: a random vibration signal, a harmonic vibration signal, or a step vibration signal.
The present invention also provides a vibration control system comprising: the device comprises a vibration source, an adder, a first vibration controller, a second vibration controller and an oscilloscope;
the vibration source is used for generating an initial vibration signal;
the adder is used for performing addition operation on the initial vibration signal and outputting the initial vibration signal to the first vibration controller;
the first vibration controller is used for carrying out first vibration control on the initial vibration signal, calculating a residual error signal and outputting the residual error signal to the second vibration controller;
the second vibration controller is used for carrying out vibration control on the residual error signal for the second time.
Compared with the prior art, the method has the advantages that the vibration suppression effect is improved and the convergence precision is improved in a mode of combining the RLS algorithm and the self-adaptive fuzzy PID algorithm.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same blocks. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.
Fig. 1 shows a basic structure of an active vibration control method provided in accordance with an embodiment of the present invention.
As shown in fig. 1, a vibration control system according to an embodiment of the present invention includes: the vibration source, the adder, the first vibration controller, the differentiator, the second vibration controller and the oscilloscope.
The vibration source may generate an initial vibration signal comprising: random vibration signals, harmonic vibration signals, step vibration signals, and the like.
The initial vibration signal generated by the vibration source is added by an adder and then transmitted to the first vibration controller; for the purpose of vibration control, the desired value is set to zero at the adder, and when the desired value is zero, the vibration signal is also continuously approaching zero.
The first vibration controller is a vibration active controller based on an RLS (recursive least squares) algorithm, inputs an expected value, an initial vibration signal u (n) and a weight w (n) of the first vibration controller into the first vibration controller for first vibration suppression, calculates a residual error signal e (n), and outputs the residual error signal e (n) to the second vibration controller.
The second vibration controller is an active controller for automatically tuning PID parameters based on a fuzzy algorithm, and can be combined into a self-adaptive fuzzy P controller, a self-adaptive fuzzy PD controller and a self-adaptive fuzzy PI controller according to specific conditions. Inputting the residual error signal e (n) of the first vibration controller into a second vibration controller for secondary vibration suppression, setting the parameters of the second vibrator on line to achieve the optimal vibration active control effect, and calculating a residual vibration signal U (n), wherein the residual vibration signal U (n) is a signal after vibration suppression.
The vibration control method based on the RLS and the self-adaptive fuzzy PID hybrid algorithm has the advantages of high response speed, good robustness and excellent vibration reduction effect under the excitation of random vibration signals, harmonic vibration signals and step vibration signals.
Fig. 2 shows a flow of a vibration active control method provided according to an embodiment of the present invention.
As shown in fig. 2, the active vibration control method of the present invention includes the steps of:
and S1, generating an initial vibration signal through a vibration source.
The vibration source may generate an initial vibration signal comprising: random vibration signals, harmonic vibration signals, step vibration signals, and the like.
And S2, inputting the initial vibration signal and the expected value to the first vibration controller to perform first vibration control, and calculating a residual error signal.
The actual output value of the first vibration controller is:
y(n)=w(n)Tu(n) (1.15)
wherein u (n) is the initial vibration signal, w (n) is the weight of the first vibration controller, and n is the time.
The difference between the expected output value d (n) and the actual output value y (n) of the first vibration controller is a residual error signal.
The residual error signal of the first vibration controller is:
e(n)=d(n)-y(n) (1.16)
where d (n) is the desired output value of the first vibration controller.
The first vibration controller calculates an output value according to the weight; the weight is adaptively changed according to the input signal, so the output of the first vibration controller is also adaptively changed according to the input signal.
The updating calculation formula of the weight is as follows:
w (n) w (n-1) + k (n) e (n) (1.17) wherein the gain vector k (n) is calculated by:
wherein λ is a forgetting factor.
The covariance matrix p (n) is calculated as:
since the whole calculation process is a random process, the fluctuation condition of the vibration signal in the expected vicinity is examined through the covariance matrix of the input signal.
And S3, outputting the residual error signal to a second vibration controller to perform the second vibration control.
The residual vibration signal is calculated by the formula:
wherein, KP、KI、KDSetting proportion coefficient under fuzzy rule; n is the filter coefficient of the PID controller, TsFor discrete time, 1/S is the time constant after Laplace transform.
Proportionality coefficient K under fuzzy ruleP、KI、KDThe calculation formula of (2) is as follows:
KP0is said KPAn initial value of (1); Δ KPA parameter change value adjusted for the adaptive fuzzy controller;
KI0is said KIAn initial value of (1); Δ KIA parameter change value adjusted for the adaptive fuzzy controller;
KD0is said KDAn initial value of (1); Δ KDA parameter change value adjusted for the adaptive fuzzy controller.
Given the ambiguity domain of error versus error variation:
e,ec={-1000,-500,-100,0,100,500,1000}
the ambiguity field is the variation range of the PID error in manual PID tuning, namely the error acceptable by the system. The error change is the derivative of the error. The active controller based on the fuzzy algorithm self-tuning PID parameters calculates the change of three tuning proportion coefficients of the PID at the moment according to the error and the error change, thereby achieving the purpose of parameter tuning.
wherein NB represents negative large; NM represents negative; NS represents minus or minus; ZO represents zero; PS means positive small; PM means median; PB indicates positive large.
The fuzzy subset is an adjusting rule, and the relationship between the fuzzy subset and the adjusting rule is that values at different moments are adjusted according to instructions of a controller.
Fig. 3 shows a Simulink model of the vibration active control method provided by the embodiment of the invention.
As shown in fig. 3, under a Simulink platform, a Simulink model of a vibration active control method based on an RLS-adaptive fuzzy PID hybrid algorithm is built, an RLS controller is compiled through a custom function based on the Simulink, and an adaptive fuzzy PID controller is compiled through a Simulink fuzzy control toolbox.
Fig. 4 shows the vibration control effect of the vibration active control method provided by the embodiment of the invention under the excitation of random signals.
Fig. 5 shows the vibration control effect of the vibration active control method provided by the embodiment of the invention under the excitation of harmonic signals.
Fig. 6 shows the vibration control effect of the vibration active control method provided by the embodiment of the invention under the excitation of the step signal.
As shown in fig. 4, 5 and 6, the vibration control method based on the RLS-adaptive fuzzy PID hybrid algorithm has a very obvious vibration suppression effect under excitation of random signals, harmonic signals and step signals.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.