Active vibration control method based on four-rotor centrifugal actuator

Abstract

The invention provides an active vibration control method based on a four-rotor centrifugal actuator, relates to the field of active vibration control, and solves the problems of limited control effect and high algorithm complexity of active damping, FxLMS algorithms and the like which are widely used in an active control system. According to the technical scheme, the method comprises the steps of collecting vibration signals at the controlled vibration characteristic frequency and a measuring point, iteratively updating the amplitude and phase of an actuating force, decomposing the amplitude and phase information of the actuating force to a position ring and a rotating speed ring of each motor of the four-rotor centrifugal actuator, and finally achieving coupling synchronous control over the four motors. Compared with an existing vibration active control strategy based on the four-rotor centrifugal actuator, the method provided by the invention has the advantages that the complexity of an active control algorithm is reduced, meanwhile, the coupling degree of four-motor synchronous control is reduced, and the practical value is higher. The method is suitable for active vibration control of helicopters and ships.

Description

Technical Field

[0001] The invention relates to the field of active vibration control, and in particular to an active vibration control method based on a four-rotor centrifugal actuator. Background Art

[0002] Active vibration control based on centrifugal actuators is an important research direction in the current field of vibration control. Centrifugal actuators have shown good application potential in vibration control due to their unique working principles and structural characteristics. Centrifugal actuators drive the eccentric mass block to rotate through a motor to generate periodic centrifugal force, thereby suppressing the vibration of the structure. The active vibration control system based on centrifugal actuators generally includes two control subsystems, namely, an active control system for generating target actuating force and a multi-motor drive control system. The active control system usually uses active damping, FxLMS algorithm, etc. to generate the target actuating force, which is decomposed into the position loop and speed loop input of each motor through the multi-motor drive control system, thereby controlling the motor to synthesize the centrifugal force generated by the eccentric rotor into the target actuating force.

[0003] In active control systems, the currently widely used active damping and FxLMS algorithms have shortcomings such as limited control effect and high algorithm complexity. Multi-motor collaborative control also has problems such as high system coupling and complex control, which seriously limit the widespread application of vibration active control systems based on centrifugal actuators in engineering. Summary of the invention

[0004] Purpose of the invention: The present invention provides a vibration active control method based on a four-rotor centrifugal actuator to solve the problems of poor control effect and complex control algorithm implementation in the vibration active control systems of equipment such as helicopters and ships.

[0005] The technical solution of the present invention is a vibration active control method based on a four-rotor centrifugal actuator, comprising the following steps:

[0006] Step 1: Obtain the transfer function model from the actuating force in the active control system to the vibration response at the target position of the structure, and construct a secondary channel filter;

[0007] Step 2: Obtain the main characteristic frequency of the vibration source through the measuring device, and measure the vibration acceleration signal at the target position of the structure through the measuring device;

[0008] Step 3: Set the step size 1 and step size 2 of parameter iteration update, and set the target force amplitude and initial phase to 0;

[0009] Step 4: Use the obtained vibration source characteristic frequency to construct the input signal 1 in the form of sine trigonometric function, and use the obtained vibration source characteristic frequency to construct the input signal 2 in the form of cosine trigonometric function;

[0010] Step 5: Filter the input signal 1 and the input signal 2 through the secondary channel filter respectively to obtain the reference signal 1 and the reference signal 2;

[0011] Step 6: Calculate the target actuation force amplitude using reference signal 1, update step size 1 and the vibration response at the target position to obtain active controller output signal 1;

[0012] Step 7: Calculate the initial phase of the target actuating force using the active controller output signal 1, the reference signal 2, the update step 2 and the vibration response at the target position to obtain the active controller output signal 2;

[0013] Step 8: Calculate the phase difference between the two eccentric rotors rotating in the same direction from the active controller output signal 1;

[0014] Step 9: Pass the active controller output signal 2 obtained in step 7 through a controller to obtain the motor target speed trajectory, and input it to the actuator drive control system;

[0015] Step 10: The motor drive control system receives the target angles and speeds of the four motors in each control cycle, and adjusts the rotation speeds of the four motors in real time to ensure that the output actuating force follows the target actuating force.

[0016] Furthermore, the centrifugal force generated by the four motors driving the four eccentric mass blocks in the four-rotor centrifugal actuator is the combined actuating force F a for:

[0017]

[0018] Where m is the mass of a single eccentric block, ω is the reference speed of the motor, r is the radius of the eccentric rotor, α is the phase difference between the two eccentric rotors rotating in the same direction, is the initial phase of the rotor, and t is the time. t Written as the actual combined force F a The same trigonometric form:

[0019]

[0020] Where Δt is the sampling interval and k represents the kth time step.

[0021] Furthermore, in step 1, let the secondary channel filter model be C and the order be J; in step 2, the characteristic frequency of the vibration source is the same as the motor reference speed ω, and the vibration response at the target position of the structure is e(k). Assuming that the disturbance source acts on the primary path, the disturbance response generated is d(k), and we have;

[0022]

[0023] To obtain a and The optimal value of , defines the objective function J0:

[0024] J0(k)=E{e 2 (k)} (4)

[0025] E{e 2 (k)} represents e 2 The expected value of (k) is Taking partial derivatives, we get:

[0026]

[0027] Furthermore, in step 4, the input signal 1 at time k is constructed as x1(k), and the input signal 2 is constructed as x2(k), and we have:

[0028] x1(k)=sin(ω·k·Δt) (7)

[0029] x2(k)=cos(ω·k·Δt) (8)

[0030] Furthermore, in step 5, let x1(k) and x2(k) pass through the secondary channel filter C respectively. Assuming that the obtained reference signal 1 is r1(k) and the obtained reference signal 2 is r2(k), we have:

[0031]

[0032]

[0033] Substituting (10) into (5), we can obtain the updated gradient of parameter a as:

[0034]

[0035] Furthermore, let the update step size 1 be μ1, then the update calculation formula for the target actuation force amplitude a in step 6 is obtained as follows:

[0036]

[0037] Furthermore, let the update step size 2 be μ2, then the target force phase in step 7 is obtained The update calculation formula is:

[0038]

[0039]

[0040] Linearize the parameters and let The final update formula for the parameters in steps 6 and 7 is as follows:

[0041] a(k)=a(k-1)-2·μ1·e(k-1)·r2(k-1) (15)

[0042]

[0043] Furthermore, in step eight, the phase difference α between the two eccentric rotors rotating in the same direction is obtained by equation (12) and equation (1):

[0044]

[0045] Furthermore, By iteratively approximating the target value in (2) value.

[0046] Furthermore, when the active control algorithm is applied to the four-motor actuator system, the actuation force amplitude a and the initial phase angle are all related to the phase difference of the four motors; in step nine, the angle α updated each time is used as the target value of the phase difference of the motors rotating in the same direction, and the angle updated each time is A controller is used to generate a target speed trajectory as an input to the actuator drive control system. In step 10, the actuator drive control system receives the target angles and speeds of the four motors in each control cycle, and adjusts the speeds of the four motors in real time to ensure that the output actuator force follows the target actuator force.

[0047] Beneficial effects of the present invention: The method provided by the present invention reduces the complexity of the active control algorithm and simultaneously reduces the coupling degree of the synchronous control of four motors, thus having higher practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of a four-rotor centrifugal actuator.

[0049] Figure 2 Schematic diagram of actuator output force.

[0050] Figure 3 Four-motor control system structure diagram. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The four-rotor centrifugal actuator system consists of four motors, each of which drives an eccentric rotor. Figure 1 As shown, in Figure 1 Under the configuration conditions shown, during operation, rotor 1 and rotor 3 rotate in the same direction, rotor 2 and rotor 4 rotate in the same direction, and the direction of rotation of rotors 1 and 3 is opposite to that of rotors 2 and 4.

[0053] The four centrifugal forces generated by the rotation of the four eccentric rotors eventually synthesize into a simple harmonic force. The combined centrifugal force of rotor 1 and rotor 3 is F1, and the force generated by rotor 2 and rotor 4 is equal to the amplitude of F1. Figure 2 As shown. Let m be the mass of a single eccentric block, ω be the reference speed of the motor, r be the radius of the eccentric rotor, α be the phase difference between the two eccentric rotors rotating in the same direction, is the initial phase of the rotor, and t is the time. Figure 2 In the direction of the actuating force shown, there are:

[0054]

[0055] In the direction of the force, the output force F a for:

[0056]

[0057] It can be seen from the above formula that under the condition that the motor speed and position are effectively controlled, the actuating force output by the four-rotor centrifugal actuator is in the form of cosine. t Written as the actual combined force F a The same trigonometric form:

[0058]

[0059] Where Δt is the sampling interval and k represents the kth time step.

[0060] Through model identification, the transmission relationship between the force at the actuator installation position and the acceleration signal at the acceleration sensor installation position is obtained, and the secondary channel filter model C is obtained, with an order of J; the characteristic frequency of the vibration source is the same as the motor reference speed ω, and the vibration response at the target position of the structure is e(k). Assuming that the disturbance source acts on the primary path, the disturbance response generated is d(k), and we have;

[0061]

[0062] To obtain a and The optimal value of , defines the objective function J0:

[0063] J0(k)=E{e 2 (k)} (6)

[0064] Let J0(k) be the value of a and Taking partial derivatives, we get:

[0065]

[0066] The above two equations are a and The gradient value of the parameter update is to achieve the update. Based on the motor reference speed ω, the input signal 1 at time k is constructed as x1(k), and the input signal 2 is x2(k):

[0067] x1(k)=sin(ω·k·Δt) (9)

[0068] x2(k)=cos(ω·k·Δt) (10)

[0069] x1(k) and x2(k) pass through the secondary channel filter C respectively. Assuming that the obtained reference signal 1 is r1(k) and the obtained reference signal 2 is r2(k), we have:

[0070]

[0071] So the updated gradient of parameter a is:

[0072]

[0073] Let the update step size 1 be μ1, then the update calculation formula for the target actuation force amplitude a is:

[0074] a(k)=a(k-1)-2μ1e(k-1)r2(k-1) (14)

[0075] Let update step 2 be μ2, then the target force phase is obtained The update calculation formula is:

[0076]

[0077] The phase difference α(k) between the two eccentric rotors rotating in the same direction is obtained:

[0078]

[0079] and α(k) as input quantities and input into the four-motor drive control system. The specific implementation is as follows:

[0080] First, construct a four-motor drive control system such as Figure 3As shown, motor 1 and motor 2 rotate in opposite directions, assuming that the angles they rotate in their respective coordinate systems are all positive values; the output angle of motor 1 minus the output angle of motor 2 to obtain the angle difference between the two motors, which is multiplied by -1 / 2 and fed back to the position loop of motor 1, and the angle difference is multiplied by 1 / 2 and fed back to the position loop of motor 2 to achieve synchronous control of motor 1 and motor 2. Motor 3 and motor 4 rotate in opposite directions, assuming that the angles they rotate in their respective coordinate systems are all positive values; the output angle of motor 3 minus the output angle of motor 4 to obtain the angle difference between the two motors, which is multiplied by -1 / 2 and fed back to the position loop of motor 3, and the angle difference is multiplied by 1 / 2 and fed back to the position loop of motor 4 to achieve synchronous control of motor 3 and motor 4.

[0081] Secondly, the angle difference between motor 3 and motor 1 is controlled to realize output force amplitude control. The specific implementation method is: subtract the output angle of motor 1 from the output angle of motor 3 to obtain the angle difference between motor 1 and motor 3, subtract the angle α(k) output by the controller from the angle difference to obtain the target deviation value, multiply the target deviation value by -1 / 2 and feed it back to the position loop of motor 1, multiply the target deviation value by 1 / 2 and feed it back to the position loop of motor 3 to realize the phase deviation α(k) between motor 1 and motor 3. At the same time, due to the synchronous control of motor 2 and motor 4 on motor 1 and motor 3, output force amplitude control is realized.

[0082] Finally, the controller outputs the angle Through a controller, the controller The phase difference with the actual actuator generates the velocity trajectory, and a fifth-order polynomial can be used to fit the angular velocity trajectory curve:

[0083] ω(t)=a5t 5 +a4t 4 +a3t 3 +a2t 2 +a1t+a0 (17)

[0084] Each parameter can be calculated by the following formula:

[0085]

[0086] in for The actual phase difference, T is the artificially set control period. The output of the controller is input to the speed loops of the four motors respectively, such as Figure 3 As shown, the phase control of the actuator output force is achieved.

[0087] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A vibration active control method based on a four-rotor centrifugal actuator, characterized in that: include: Measuring the characteristic frequency of the vibration of the controlled target by a measuring device; measuring a vibration acceleration signal at a target position by a measuring device; Taking the characteristic frequency of the controlled target vibration as input, constructing an input signal in the form of sine and cosine trigonometric functions; Filtering the input signal through a secondary channel filter to obtain a filtering reference signal; Given the initial values ​​of the target actuation force amplitude and phase, the target actuation force amplitude and phase are updated in each sampling period using the reference signal, the filtered reference signal and the vibration acceleration signal.

2. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 1, characterized in that: The implementation steps include: Step 1: Obtain the transfer function model from the actuating force in the active control system to the vibration response at the target position of the structure, and construct a secondary channel filter; Step 2: Obtain the main characteristic frequency of the vibration source through the measuring device, and measure the vibration acceleration signal at the target position of the structure through the measuring device; Step 3: Set the step size 1 and step size 2 of parameter iteration update, and set the target force amplitude and initial phase to 0; Step 4: Use the obtained vibration source characteristic frequency to construct the input signal 1 in the form of sine trigonometric function, and use the obtained vibration source characteristic frequency to construct the input signal 2 in the form of cosine trigonometric function; Step 5: Filter the input signal 1 and the input signal 2 through the secondary channel filter respectively to obtain the reference signal 1 and the reference signal 2; Step 6: Calculate the target actuation force amplitude using reference signal 1, update step size 1 and the vibration response at the target position to obtain active controller output signal 1; Step 7: Calculate the initial phase of the target actuation force using the active controller output signal 1, the reference signal 2, the update step 2 and the vibration response at the target position to obtain the active controller output signal 2; Step 8: Calculate the phase difference between the two eccentric rotors rotating in the same direction from the active controller output signal 1; Step 9: Pass the active controller output signal 2 obtained in step 7 through a controller to obtain the motor target speed trajectory, and input it to the actuator drive control system; Step 10: The motor drive control system receives the target angles and speeds of the four motors in each control cycle, and adjusts the rotation speeds of the four motors in real time to ensure that the output actuating force follows the target actuating force.

3. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 2, characterized in that: The combined actuating force F of the four eccentric mass blocks driven by four motors in the four-rotor centrifugal actuator a for: Where m is the mass of a single eccentric block, ω is the reference speed of the motor, r is the radius of the eccentric rotor, α is the phase difference between the two eccentric rotors rotating in the same direction, is the initial phase of the rotor, t is the time; the target is the force F t Written as the actual combined force F a The same trigonometric form: Where Δt is the sampling interval and k represents the kth time step.

4. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 3, characterized in that: Let the secondary channel filter model be C and the order be J; the characteristic frequency of the vibration source is the same as the motor reference speed ω, the vibration response at the target position of the structure is e(k), and assuming that the disturbance source acts on the primary path and the disturbance response generated is d(k), we have; To obtain a and The optimal value of , defines the objective function J0: J0(k)=E{e 2 (k)} (4) E{e 2 (k)} represents e 2 The expected value of (k) is Taking partial derivatives, we get:

5. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step 4, construct the input signal 1 at time k as x1(k) and the input signal 2 as x2(k), and we have: x1(k)=sin(ω·k·Δt) (7) x2(k)=cos(ω·k·Δt) (8).

6. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step 5, let x1(k) and x2(k) pass through the secondary channel filter C respectively. Assuming that the obtained reference signal 1 is r1(k) and the reference signal 2 is r2(k), we have: Substituting (10) into (5), we can obtain the updated gradient of parameter a as:

7. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step 6, let the update step size 1 be μ1, then the update calculation formula for the target actuation force amplitude a in step 6 is obtained as follows:

8. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step 7, let the update step size 2 be μ2, then the target force phase in step 7 is obtained The update calculation formula is: Linearize the parameters and let The final update formula for the parameters in steps 6 and 7 is as follows: a(k)=a(k-1)-2·μ1·e(k-1)·r2(k-1) (15) 9. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step eight, the phase difference α between the two eccentric rotors rotating in the same direction is obtained by equation (12) and equation (1):

10. The method for active vibration control based on a four-rotor centrifugal actuator according to claim 4, characterized in that: In step nine, the angle α updated each time is used as the target value of the phase difference of the motors rotating in the same direction. A controller is used to generate a target speed trajectory as an input to the actuator drive control system. In step 10, the actuator drive control system receives the target angles and speeds of the four motors in each control cycle, and adjusts the speeds of the four motors in real time to ensure that the output actuator force follows the target actuator force.

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