Method for accurately calculating transmission efficiency of aerospace electromechanical servo actuator

Abstract

The invention provides a method for accurately calculating the transmission efficiency of an aerospace electromechanical servo actuator, and relates to the field of servo actuators. The method for accurately calculating the transmission efficiency of the spaceflight electromechanical servo actuator comprises the following steps that S1, the spaceflight electromechanical servo actuator drives a ball screw to generate linear displacement mainly through a permanent magnet synchronous motor directly or by being connected with a reduction gearbox; and S2, the whole electromechanical servo actuator and the rocket engine jet pipe are fixed together through an upper supporting lug nut, an upper supporting lug bolt, a lower supporting lug nut and a lower supporting lug bolt. According to the electromechanical servo actuator, the structural design of the electromechanical servo actuator is optimized, the transmission efficiency of the actuator is accurate, the structure of the actuator can be designed more reasonably according to the accurate transmission efficiency, the weight of the actuator is further reduced, more theoretical bases are provided for design of the electromechanical servo actuator, and when a fault occurs, the electromechanical servo actuator can be effectively protected. And the accident reason can be found more accurately.

Description

Technical Field

[0001] The invention relates to the field of servo actuators, and in particular to a method for accurately calculating the transmission efficiency of aerospace electromechanical servo actuators. Background Art

[0002] With the development of computer technology, motor technology and power electronics technology, especially the progress of motor technology and high-power electronic components technology, electromechanical servo mechanisms have developed rapidly. Electromechanical servo has long been used in the "Vega" carrier model abroad. Domestic related technologies have made substantial breakthroughs since 2010. Related products have been verified by dozens of flights of multiple aerospace models and currently have a high degree of technical maturity.

[0003] However, at present, when designing electromechanical servo mechanisms, the energy transfer efficiency of each transmission link is generally estimated based on products with flight experience models. There is no systematic calculation method and it is often too conservative, which greatly limits the further streamlining of the overall layout of the electromechanical servo mechanism.

[0004] At present, the transmission efficiency of AESC servo actuators is designed according to product parameters with flight experience or according to the minimum transmission efficiency provided by suppliers. The design is based on the parameters of existing models, which limits the development of AESC servo mechanisms. In addition, the parameter design lacks a theoretical basis. In extreme cases, it is difficult to predict whether the product design is conservative or radical, which may lead to unpredictable accidents.

[0005] Therefore, those skilled in the art provide a method for accurately calculating the transmission efficiency of an aerospace mechanical servo actuator to solve the problems raised in the above background technology. Summary of the invention

[0006] 1. Technical issues to be solved

[0007] In view of the deficiencies in the prior art, the present invention provides a method for accurately calculating the transmission efficiency of an aerospace electromechanical servo actuator, optimizes the structural design of the electromechanical servo actuator, and provides a theoretical basis for the transmission efficiency of the actuator. This solves the problem that the transmission efficiency of the aerospace electromechanical servo actuator is currently designed according to product parameters with flight experience or according to the minimum transmission efficiency provided by the supplier. The design is based on the product parameters of existing models, which limits the development of aerospace electromechanical servo mechanisms. In addition, the parameter design lacks a theoretical basis. In extreme cases, it is difficult to predict whether the product design is conservative or radical, which may lead to unpredictable accidents.

[0008] (II) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] A method for accurately calculating the transmission efficiency of an aerospace electromechanical servo actuator comprises the following steps:

[0011] Step S1. The aerospace electromechanical servo actuator mainly generates linear displacement by driving a ball screw directly or by connecting a reduction gearbox through a permanent magnet synchronous motor;

[0012] Step S2. The entire electromechanical servo actuator is fixed to the rocket engine nozzle through the upper lug nut, the upper lug bolt, the lower lug nut, and the lower lug bolt;

[0013] Step S3. Use a permanent magnet synchronous motor to drive the ball screw to move, and the rocket engine nozzle swings accordingly;

[0014] Step S4. Calculating the output energy of the permanent magnet synchronous motor;

[0015] Step S5. The energy outputted by the permanent magnet synchronous motor is transferred to the rocket engine nozzle by means of the ball screw;

[0016] Step S6. Calculate the received energy of the rocket engine.

[0017] Furthermore, the electromechanical servo actuator adopts a surface-mounted permanent magnet synchronous motor, and the requirement for the rotation speed is not high.

[0018] Furthermore, in step S4, the process of calculating the output energy of the permanent magnet synchronous motor is as follows:

[0019] 1) The energy output by the servo motor is equal to the integral of the motor power and the swing time during the nozzle swing process, that is:

[0020]

[0021] Among them, the motor power can be obtained based on the motor output torque and motor speed;

[0022] 2) To ensure the maximum output torque of the motor, the control system uses the direct-axis current to control the surface-mounted permanent magnet synchronous motor. After the motor is determined, the output torque depends entirely on the quadrature-axis current, that is:

[0023] T 电机 =i q ×K t

[0024] In the formula, K t is the motor torque coefficient, i q It is the system feedback quantity and can be collected in real time;

[0025] 3) The motor speed is obtained according to the displacement curve fed back by the engine nozzle, and is calculated according to the sinusoidal position curve of the engine nozzle, that is:

[0026] θ 喷管 =θ0×sin(ω·t)

[0027] Where θ0 is the nozzle swing angle amplitude, ω is the nozzle swing angular frequency;

[0028] Therefore, the engine nozzle angular velocity satisfies:

[0029]

[0030] 4) According to the installation position coordinates of the electromechanical actuator on the rocket engine nozzle and the rotation center coordinates of the nozzle, the reduction ratio of the motor speed to the engine nozzle is obtained, denoted as i, so the motor speed satisfies:

[0031]

[0032] Therefore, the motor output power can be expressed as:

[0033]

[0034] Furthermore, the controller sampling period is recorded as T s Therefore, the energy output by the servo motor in one sinusoidal position command cycle of the nozzle is:

[0035]

[0036] Where P j represents the output power of the motor at the jth sampling period, T / T s Indicates the total number of samples in one sinusoidal position command cycle.

[0037] Furthermore, in step S5, the process of calculating the received energy of the rocket engine is as follows:

[0038] 1) The rocket engine nozzle is displaced by the ball screw, so the energy input from the ball screw to the nozzle can be expressed as:

[0039]

[0040] 2) The ball screw moves back and forth in a straight line under the motor, so the screw moves at a speed v 丝杠 It can be expressed as:

[0041]

[0042] Where p represents the lead of the ball screw;

[0043] 3) Since the solid rocket engine nozzle is an elastic load, the load force changes according to a certain torque gradient, so the force on the screw is expressed as:

[0044]

[0045] Where k represents the torque gradient corresponding to the unit angle of the nozzle movement, θ 喷管 It represents the swing angle of the nozzle relative to the starting point, and l represents the force arm of the nozzle relative to the screw at the corresponding swing angle.

[0046] Furthermore, in the step S6, it also includes:

[0047] 1) The controller sampling period is recorded as, so in one sinusoidal position instruction period, the energy received by the nozzle from the lead screw is:

[0048]

[0049] In the formula, F j 、v j It represents the force on the screw at the jth sampling period and the average speed of the screw during the sampling period, T / T s Indicates the total number of samples within a sinusoidal position command cycle;

[0050] 2) Based on the above, it can be concluded that the energy utilization rate of the nozzle from the motor input to the nozzle receiving process within a sinusoidal position command cycle, that is, the transmission efficiency is:

[0051]

[0052] Furthermore, the electromechanical servo actuator adopts a linear servo actuator, including an upper lug nut, an upper lug, an upper lug bolt, a permanent magnet synchronous motor, a ball screw, a lower lug nut, a lower lug and a lower lug bolt, the ball screw is fixedly connected to the output end of the permanent magnet synchronous motor, the upper lug is fastened to the end of the permanent magnet synchronous motor by a screw, and the end of the ball screw away from the permanent magnet synchronous motor is connected to the lower lug by a thread.

[0053] Furthermore, the upper lug and the lower lug are fixedly connected to the rocket engine nozzle through an upper lug nut, an upper lug bolt, a lower lug nut, and a lower lug bolt, thereby connecting the entire electromechanical servo actuator to the rocket engine nozzle.

[0054] (III) Beneficial effects

[0055] The present invention provides a method for accurately calculating the transmission efficiency of aerospace mechanical servo actuators. It has the following beneficial effects:

[0056] 1. The present invention provides a method for accurately calculating the transmission efficiency of aerospace electromechanical servo actuators. Starting from the input energy of the servo motor and the received energy of the rocket engine, the energy loss of the ball screw and the rocket engine is accurately calculated, and then the transmission efficiency of the servo actuator is obtained.

[0057] 2. The present invention provides a method for accurately calculating the transmission efficiency of aerospace electromechanical servo actuators, optimizes the structural design of electromechanical servo actuators, and makes the transmission efficiency of the actuators more precise. The actuator structure can be designed more reasonably based on the precise transmission efficiency, and the weight of the actuator can be further reduced. It also provides more theoretical basis for the design of electromechanical servo actuators, and when a failure occurs, the cause of the accident can be found more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic structural diagram of the linear servo actuator of the present invention.

[0059] Among them, 1. upper support ear nut; 2. upper support ear; 3. upper support ear bolt; 4. permanent magnet synchronous motor; 5. ball screw; 6. lower support ear nut; 7. lower support ear; 8. lower support ear bolt. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the specific embodiments of the present invention to clearly and completely describe the technical solutions in the specific embodiments of the present invention. Obviously, the specific embodiments described are only part of the specific embodiments of the present invention, not all of the specific embodiments. Based on the specific embodiments of the present invention, all other specific embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific implementation method:

[0062] like Figure 1 As shown, a specific embodiment of the present invention provides a device for accurately calculating the transmission efficiency of an aerospace electromechanical servo actuator. The electromechanical servo actuator adopts a linear servo actuator, including an upper lug nut 1, an upper lug 2, an upper lug bolt 3, a permanent magnet synchronous motor 4, a ball screw 5, a lower lug nut 6, a lower lug 7 and a lower lug bolt 8. The ball screw 5 is fixedly connected to the output end of the permanent magnet synchronous motor 4, the upper lug 2 is fastened to the end of the permanent magnet synchronous motor 4 by a screw, and the end of the ball screw 5 away from the permanent magnet synchronous motor 4 is connected to the lower lug 7 by a thread.

[0063] The upper lug 2 and the lower lug 7 are fixedly connected to the rocket engine nozzle through the upper lug nut 1, the upper lug bolt 3, the lower lug nut 6 and the lower lug bolt 8, thereby connecting the entire electromechanical servo actuator to the rocket engine nozzle.

[0064] A specific implementation of the root application, a method for accurately calculating the transmission efficiency of an aerospace electromechanical servo actuator, comprises the following steps:

[0065] Step S1. The aerospace electromechanical servo actuator mainly generates linear displacement by driving the ball screw 5 directly or by connecting a reduction gearbox through the permanent magnet synchronous motor 4;

[0066] Step S2. The entire electromechanical servo actuator is fixed to the rocket engine nozzle through the upper lug nut 1, the upper lug bolt 3, the lower lug nut 6, and the lower lug bolt 8;

[0067] Step S3. Use the permanent magnet synchronous motor 4 to drive the ball screw 5 to move, and the rocket engine nozzle swings accordingly;

[0068] Step S4. Calculate the output energy of the permanent magnet synchronous motor 4;

[0069] Step S5. The energy outputted by the permanent magnet synchronous motor 4 is transferred to the rocket engine nozzle by transferring the energy through the ball screw 5;

[0070] Step S6. Calculate the received energy of the rocket engine.

[0071] In step S4, the process of calculating the output energy of the permanent magnet synchronous motor 4 is as follows:

[0072] 1 The energy output by the servo motor is equal to the integral of the motor power and the swing time during the nozzle swing process, that is:

[0073]

[0074] Among them, the motor power can be obtained based on the motor output torque and motor speed;

[0075] 2 To ensure the maximum output torque of the motor, the control system uses the direct-axis current to control the surface-mounted permanent magnet synchronous motor. After the motor is determined, the output torque depends entirely on the quadrature-axis current, that is:

[0076] T 电机 =i q ×K t

[0077] In the formula, K t is the motor torque coefficient, i q It is the system feedback quantity and can be collected in real time;

[0078] 3 The motor speed is obtained according to the displacement curve fed back by the engine nozzle, and is calculated according to the sinusoidal position curve of the engine nozzle, that is:

[0079] θ 喷管=θ0×sin(ω·t)

[0080] Where θ0 is the nozzle swing angle amplitude, ω is the nozzle swing angular frequency;

[0081] Therefore, the engine nozzle angular velocity satisfies:

[0082]

[0083] 4 According to the installation position coordinates of the electromechanical actuator on the rocket engine nozzle and the rotation center coordinates of the nozzle, the reduction ratio of the motor speed to the engine nozzle is obtained, denoted as i, so the motor speed satisfies:

[0084]

[0085] Therefore, the motor output power can be expressed as:

[0086]

[0087] The controller sampling period is denoted as T s Therefore, the energy output by the servo motor in one sinusoidal position command cycle of the nozzle is:

[0088]

[0089] Where P j represents the output power of the motor at the jth sampling period, T / T s Indicates the total number of samples in one sinusoidal position command cycle.

[0090] In step S5, the process of calculating the received energy of the rocket engine is as follows:

[0091] 1 The rocket engine nozzle is displaced under the push of the ball screw, so the energy input to the nozzle by the ball screw can be expressed as:

[0092]

[0093] 2 The ball screw moves back and forth in a straight line under the motor, so the screw moves at a speed v 丝杠 It can be expressed as:

[0094]

[0095] Where p represents the lead of the ball screw;

[0096] 3 Since the solid rocket engine nozzle is an elastic load, the load force changes according to a certain torque gradient, so the force on the screw is expressed as:

[0097]

[0098] Where k represents the torque gradient corresponding to the unit angle of the nozzle movement, θ 喷管 It represents the swing angle of the nozzle relative to the starting point, and l represents the force arm of the nozzle relative to the screw at the corresponding swing angle.

[0099] In step S6, it also includes:

[0100] 1 The controller sampling period is recorded as, so in one sinusoidal position instruction period, the energy input by the nozzle to the lead screw is:

[0101]

[0102] In the formula, F j 、v j It represents the force on the screw at the jth sampling period and the average speed of the screw during the sampling period, T / T s Indicates the total number of samples within a sinusoidal position command cycle;

[0103] 2 Based on the above, it can be concluded that the energy utilization rate of the nozzle from the motor input to the nozzle receiving process within a sinusoidal position command cycle, that is, the transmission efficiency is:

[0104]

[0105] The patent uses the example of the nozzle making a sinusoidal position, but this patent can perfectly solve the nozzle making any other instruction movement, so it is all within the protection scope of this patent;

[0106] This patent uses a linear electromechanical actuator as an example, but for other types of actuators, as long as the core idea of ​​solving the transmission efficiency is consistent with this patent, they are within the scope of protection of this patent.

[0107] Although specific embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the specific embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for accurately calculating the transmission efficiency of aerospace mechanical servo actuators, characterized in that: The following steps are involved: Step S1. The aerospace electromechanical servo actuator mainly generates linear displacement by driving a ball screw (5) directly or by connecting a reduction gearbox via a permanent magnet synchronous motor (4); Step S2. The entire electromechanical servo actuator is fixed to the rocket engine nozzle through the upper lug nut (1), the upper lug bolt (3), the lower lug nut (6), and the lower lug bolt (8); Step S3. Use the permanent magnet synchronous motor (4) to drive the ball screw (5) to move, and the rocket engine nozzle swings accordingly; Step S4. Calculating the output energy of the permanent magnet synchronous motor (4); Step S5. The energy outputted by the permanent magnet synchronous motor (4) is transferred to the rocket engine nozzle by transferring energy through the ball screw (5); Step S6. Calculate the received energy of the rocket engine.

2. The method for accurately calculating the transmission efficiency of aerospace mechanical servo actuator according to claim 1 is characterized in that: The electromechanical servo actuator adopts a surface-mounted permanent magnet synchronous motor, and the requirement for the rotation speed is not high.

3. The method for accurately calculating the transmission efficiency of an aerospace mechanical servo actuator according to claim 1, characterized in that: In step S4, the process of calculating the output energy of the permanent magnet synchronous motor (4) is as follows: 1) The energy output by the servo motor is equal to the integral of the motor power and the swing time during the nozzle swing process, that is: E 电机 =∫0 t P 电机 d t Among them, the motor power can be obtained based on the motor output torque and motor speed; 2) To ensure the maximum output torque of the motor, the control system uses the direct-axis current to control the surface-mounted permanent magnet synchronous motor. After the motor is determined, the output torque depends entirely on the quadrature-axis current, that is: T 电机 =i q ×K t In the formula, K t is the motor torque coefficient, i q It is the system feedback quantity and can be collected in real time; 3) The motor speed is obtained according to the displacement curve fed back by the engine nozzle, and is calculated according to the sinusoidal position curve of the engine nozzle, that is: i 喷管 =θ0×sin(ω·t) Where θ0 is the nozzle swing angle amplitude, ω is the nozzle swing angular frequency; Therefore, the engine nozzle angular velocity satisfies: 4) According to the installation position coordinates of the electromechanical actuator on the rocket engine nozzle and the rotation center coordinates of the nozzle, the reduction ratio of the motor speed to the engine nozzle is obtained, denoted as i, so the motor speed satisfies: Therefore, the motor output power can be expressed as:

4. The method for accurately calculating the transmission efficiency of an aerospace mechanical servo actuator according to claim 3 is characterized in that: The controller sampling period is denoted as T s Therefore, the energy output by the servo motor in one sinusoidal position command cycle of the nozzle is: Where P j represents the output power of the motor at the jth sampling period, T / T s Indicates the total number of samples in one sinusoidal position command cycle.

5. The method for accurately calculating the transmission efficiency of aerospace mechanical servo actuator according to claim 1, characterized in that: In step S5, the process of calculating the received energy of the rocket engine is as follows: 1) The rocket engine nozzle is displaced by the ball screw, so the energy input from the ball screw to the nozzle can be expressed as: E 喷管 =∫0 t F 丝杠 v 丝杠 d t 2) The ball screw moves back and forth in a straight line under the motor, so the screw moves at a speed v 丝杠 It can be expressed as: Where p represents the lead of the ball screw; 3) Since the solid rocket engine nozzle is an elastic load, the load force changes according to a certain torque gradient, so the force on the screw is expressed as: Where k represents the torque gradient corresponding to the unit angle of the nozzle movement, θ 喷管 It represents the swing angle of the nozzle relative to the starting point, and l represents the force arm of the nozzle relative to the screw at the corresponding swing angle.

6. The method for accurately calculating the transmission efficiency of aerospace mechanical servo actuator according to claim 5, characterized in that: In the step S6, it also includes: 1) The controller sampling period is recorded as, so in one sinusoidal position instruction period, the energy received by the nozzle from the lead screw is: In the formula, F j 、v j It represents the force on the screw at the jth sampling period and the average speed of the screw during the sampling period, T / T s Indicates the total number of samples within a sinusoidal position command cycle; 2) Based on the above, it can be concluded that the energy utilization rate of the nozzle from the motor input to the nozzle receiving process within a sinusoidal position command cycle, that is, the transmission efficiency is:

7. The method for accurately calculating the transmission efficiency of aerospace mechanical servo actuator according to claim 1, characterized in that: The electromechanical servo actuator adopts a linear servo actuator, comprising an upper lug nut (1), an upper lug (2), an upper lug bolt (3), a permanent magnet synchronous motor (4), a ball screw (5), a lower lug nut (6), a lower lug (7) and a lower lug bolt (8), wherein the ball screw (5) is fixedly connected to the output end of the permanent magnet synchronous motor (4), the upper lug (2) is fastened to the end of the permanent magnet synchronous motor (4) by means of screws, and the end of the ball screw (5) away from the permanent magnet synchronous motor (4) is connected to the lower lug (7) by means of threads.

8. The electromechanical servo actuator according to claim 7, characterized in that: The upper lug (2) and the lower lug (7) are fixedly connected to the rocket engine nozzle via an upper lug nut (1), an upper lug bolt (3), a lower lug nut (6), and a lower lug bolt (8), thereby connecting the entire electromechanical servo actuator to the rocket engine nozzle.

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