Method for measuring rigidity of aerospace electromechanical servo actuator

Abstract

The invention provides a method for measuring the rigidity of an aerospace electromechanical servo actuator, and relates to the field of rigidity measurement of electromechanical servo actuators. The method for measuring the rigidity of the spaceflight electromechanical servo actuator comprises the following steps that S1, the spaceflight electromechanical servo actuator generates linear telescopic motion, then a rotating torque is generated through a motor, and the rotating motion is converted into linear displacement through a ball screw; s2, linear displacement generated by the aerospace electromechanical servo actuator is measured through a linear displacement sensor, and the number of rotation turns of the motor is measured through a rotary transformer. According to the method, the cost of stiffness measurement of the electromechanical actuator is greatly reduced while the measurement precision is guaranteed, the test process is greatly simplified, the stiffness of the actuator can be measured without additionally arranging a sensor, the actuator can be measured when being loaded, the measurement mode is simple and efficient, and the measurement accuracy is high. The product structure of the aerospace electromechanical actuator is fully utilized, and the use cost is lower.

Description

Technical Field

[0001] The invention relates to the field of stiffness measurement of electromechanical servo actuators, and in particular to a method for measuring stiffness of aerospace electromechanical servo actuators. Background Art

[0002] Aerospace electromechanical servo actuators have extremely high application value in the aerospace field due to the elimination of hydraulic pipelines, compact structure, and easy maintenance. In recent years, with the advancement of motor technology and high-power electronic component technology, electromechanical servo mechanisms have developed rapidly. Domestic related products have also been verified by dozens of flights of multiple aerospace models, and currently have a high level of technical maturity. In order to further improve the dynamic response of the servo system, it is necessary to accurately and conveniently measure the stiffness of the servo actuator. However, when designing electromechanical servo mechanisms, the stiffness is generally given as a reference value based on simulation results or measured through complex and costly measurement devices, which is extremely inconvenient.

[0003] At present, one method of measuring the stiffness of aerospace electromechanical servo actuators in the prior art is to calculate the stiffness through simulation results of the strength of the gears, lead screws, bearings, screws and related structural parts of the electromechanical actuators. The calculation results of this measurement method have certain errors due to processing and manufacturing reasons, and the simulation results themselves have calculation errors, which makes it impossible to verify whether the calculation results are close to the actual stiffness;

[0004] Another measurement method is to install two side plates at the actuator's lead screw and rear support ear, and install two laser sensors between the side plates. When the actuator is deformed under force, the laser sensor will measure the displacement of the side plates and derive the stiffness of the actuator based on the magnitude of the force. This measurement method is more expensive and requires special measuring equipment for measurement. At the same time, the measurement efficiency is also lower and the measurement process is more complicated.

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

[0006] 1. Technical issues to be resolved

[0007] In view of the shortcomings of the prior art, the present invention provides a method for measuring the stiffness of aerospace electromechanical servo actuators. While ensuring the measurement accuracy, the method not only greatly reduces the cost of measuring the stiffness of electromechanical actuators, but also greatly simplifies the testing process. It solves the problem that the calculation results of one measurement method have certain errors due to processing and manufacturing reasons, and the simulation results themselves have calculation errors, which makes it impossible to verify whether the calculation results are close to the actual stiffness; the other measurement method has a high cost and requires a special measuring device for measurement, and the measurement efficiency is also low, and the measurement process is more complicated.

[0008] (II) Technical solution

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

[0010] A method for measuring the stiffness of an aerospace mechanical servo actuator comprises the following steps:

[0011] Step S1. The aerospace mechanical servo actuator generates a linear telescopic motion, and then generates a rotational torque through a motor, and converts the rotational motion into a linear displacement through a ball screw;

[0012] Step S2. Measuring the linear displacement generated by the aerospace mechanical servo actuator through a linear displacement sensor, and measuring the number of rotations of the motor through a rotary transformer;

[0013] Step S3. Connecting the upper support ear and the lower support ear to the load through the mounting interface to drive the load to move;

[0014] Step S4. The servo actuator converts the rotation of the motor into the telescopic movement of the ball screw without any load;

[0015] Step S5. When the servo actuator is subjected to an axial load, the deformation of the lead screw, bearings, screws and related structural parts may cause a deviation in the relationship between the elongation δ of the ball screw and the number of rotations n of the motor;

[0016] Step S6. To ensure that the motor output torque is maximized, the control system uses the direct axis current i d =0 mode control;

[0017] Step S7. The elongation of the ball screw is measured in real time by the displacement sensor provided in the electromechanical actuator, and the number of revolutions of the motor is measured in real time by the rotary transformer at the rear end of the motor.

[0018] Furthermore, in step S4, the elongation of the ball screw and the number of rotations of the motor follow the following relationship:

[0019] δ=n×P#

[0020] Where, δ′ is the elongation of the ball screw when it is subjected to axial load, n is the number of turns of the ball screw, P is the lead of the ball screw, and F 丝杠 is the axial load on the ball screw, and K is the stiffness of the electromechanical actuator.

[0021] Furthermore, in step S5, the elongation of the ball screw and the number of rotations of the motor follow the following relationship:

[0022]

[0023] Where δ′ is the elongation of the ball screw when it is subjected to axial load, n is the number of motor revolutions, P is the lead of the ball screw, and F 丝杠 is the axial load on the ball screw, and K is the stiffness of the electromechanical actuator.

[0024] Furthermore, the electromechanical servo actuator adopts a surface-mounted permanent magnet synchronous motor, and the requirement for the rotation speed is not high.

[0025] Further, in step S6, after the motor is determined, the output torque is completely dependent on the quadrature axis current, that is:

[0026] T 电机 =i q ×K t #

[0027] In the formula, K t is the motor torque coefficient, which is the basic parameter of the motor and is a fixed value under normal working conditions. q It is the motor quadrature-axis current, which is the system feedback quantity and can be collected in real time.

[0028] Further, in step S6, the motor output torque and the ball screw output axial force have the following relationship:

[0029]

[0030] In the formula, F 丝杠 is the axial force output by the ball screw, P is the lead of the ball screw, and γ is the transmission efficiency from the motor to the ball screw;

[0031] General In, we get:

[0032]

[0033] In integrated With The stiffness of the aerospace electromechanical servo actuator is obtained as:

[0034]

[0035] In the formula, i q is the motor quadrature axis current, K t is the motor torque coefficient, P is the ball screw lead, γ is the transmission efficiency from the motor to the ball screw, δ' is the elongation of the ball screw when it is subjected to axial load, and n is the number of motor revolutions.

[0036] Furthermore, the i q is the system feedback quantity, which can be collected in real time. tIt is the basic parameter of the motor, which is a fixed value when working under normal circumstances. P is the lead of the ball screw, which is also a fixed value. The transmission efficiency γ is 0.76.

[0037] Furthermore, the electromechanical servo actuator is a linear servo actuator, including an upper lug, a motor, a linear displacement sensor, a ball screw, a housing, a lower lug and a rotary transformer, wherein the motor is arranged at the rear end inside the housing, the linear displacement sensor is arranged at the front end side of the housing, the output end of the motor is connected to the ball screw and one end of the ball screw extends out of the housing and is connected to the lower lug, the upper lug is fixedly connected to the outside of the rear end of the housing, and the rotary transformer is arranged outside the motor.

[0038] (III) Beneficial effects

[0039] The present invention provides a method for measuring the stiffness of an aerospace mechanical servo actuator. It has the following beneficial effects:

[0040] 1. The present invention provides a method for measuring the stiffness of aerospace electromechanical servo actuators, which not only greatly reduces the cost of stiffness measurement of electromechanical actuators while ensuring measurement accuracy, but also greatly simplifies the test process.

[0041] 2. The present invention provides a method for measuring the stiffness of an aerospace electromechanical servo actuator. The method does not require additional sensors to measure the actuator stiffness, and the actuator can be measured when it is loaded. The measurement method is simple and efficient, fully utilizing the product structure of the aerospace electromechanical actuator, and has a lower use cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic structural diagram of the linear servo actuator of the present invention.

[0043] Among them, 1. upper support ear; 2. motor; 3. linear displacement sensor; 4. ball screw; 5. housing; 6. lower support ear; 7. rotary transformer. DETAILED DESCRIPTION

[0044] 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.

[0046] like Figure 1As shown, a specific embodiment of the present invention provides a measurement aerospace electromechanical servo actuator, the electromechanical servo actuator adopts a surface-mounted permanent magnet synchronous motor, and has low requirements on the rotation speed;

[0047] It is a linear servo actuator, including an upper lug 1, a motor 2, a linear displacement sensor 3, a ball screw 4, a housing 5, a lower lug 6 and a rotary transformer 7. The motor 2 is arranged at the rear end of the housing 5, the linear displacement sensor 3 is arranged on the front end side of the housing 5, the output end of the motor 2 is connected to the ball screw 4 and one end of the ball screw 4 extends out of the housing 5 and is connected to the lower lug 6, the upper lug 1 is fixedly connected to the outside of the rear end of the housing 5, and the rotary transformer 7 is arranged on the outside of the motor 2.

[0048] A specific embodiment of the root application, a method for measuring the stiffness of an aerospace electromechanical servo actuator, comprises the following steps:

[0049] Step S1. The aerospace mechanical servo actuator generates a linear telescopic motion, and then generates a rotational torque through the motor 2, and converts the rotational motion into a linear displacement through the ball screw 4;

[0050] Step S2. The linear displacement generated by the aerospace mechanical servo actuator is measured by the linear displacement sensor 3, and the number of rotations of the motor 2 is measured by the rotary transformer 7;

[0051] Step S3. Connecting the upper support ear 1 and the lower support ear 6 to the load through the mounting interface to drive the load to move;

[0052] Step S4. The servo actuator converts the rotation of the motor 2 into the telescopic movement of the ball screw 4 without any load;

[0053] Step S5. When the servo actuator is subjected to an axial load, the deformation of the lead screw, bearings, screws and related structural parts may cause a deviation in the relationship between the elongation δ of the ball screw 4 and the number of rotations n of the motor 2;

[0054] Step S6. To ensure that the output torque of motor 2 is maximized, the control system uses the direct axis current i d =0 mode control;

[0055] Step S7. The elongation of the ball screw 4 is measured in real time by the displacement sensor 3 provided in the electromechanical actuator, and the number of revolutions of the motor 2 is measured in real time by the rotary transformer 7 at the rear end of the motor 2.

[0056] In step S4, the extension of the ball screw 4 and the number of rotations of the motor 2 follow the following relationship: δ = n × P#

[0057] Where, δ′ is the elongation of the ball screw 4 when it is subjected to axial load, n is the number of revolutions of the ball screw 4, P is the lead of the ball screw 4, and F 丝杠 is the axial load on the ball screw 4, and K is the stiffness of the electromechanical actuator.

[0058] Furthermore, in step S5, the elongation of the ball screw 4 and the number of rotations of the motor 2 follow the following relationship:

[0059]

[0060] Where, δ′ is the elongation of the ball screw 4 when it is subjected to axial load, n is the number of revolutions of the motor 2, P is the lead of the ball screw 4, and F 丝杠 is the axial load on the ball screw 4, and K is the stiffness of the electromechanical actuator.

[0061] Furthermore, the electromechanical servo actuator uses a surface-mounted permanent magnet synchronous motor, and the requirement for the rotation speed is not high.

[0062] Further, in step S6, after the motor 2 is determined, the output torque is completely dependent on the quadrature axis current, that is:

[0063] T 电机 =i q ×K t #

[0064] In the formula, K t is the torque coefficient of motor 2, which is the basic parameter of motor 2 and is a fixed value when working under normal circumstances. q It is the quadrature-axis current of motor 2, which is the system feedback quantity and can be collected in real time.

[0065] Further, in step S6, the output torque of the motor 2 and the output axial force of the ball screw 4 have the following relationship:

[0066]

[0067] In the formula, F 丝杠 is the axial force output by the ball screw 4, P is the lead of the ball screw 4, and γ is the transmission efficiency from the motor 2 to the ball screw 4;

[0068] Type T 电机 =i q ×K t #Substitution In, we get:

[0069]

[0070] In integrated With The stiffness of the aerospace electromechanical servo actuator is obtained as:

[0071]

[0072] In the formula, i q is the quadrature axis current of motor 2, K t is the torque coefficient of motor 2, P is the lead of ball screw 4, γ is the transmission efficiency from motor 2 to ball screw 4, δ′ is the elongation of ball screw 4 when subjected to axial load, and n is the number of revolutions of motor 2.

[0073] Furthermore, q is the system feedback quantity, which can be collected in real time. t It is the basic parameter of motor 2, which is a fixed value when working under normal circumstances. P is the lead of ball screw 4, which is also a fixed value. The transmission efficiency γ is 0.76.

[0074] 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 measuring the stiffness of an aerospace mechanical servo actuator, characterized in that: The following steps are involved: Step S1. The aerospace electromechanical servo actuator generates a linear telescopic motion, and then generates a rotational torque through the motor (2), and converts the rotational motion into a linear displacement through the ball screw (4); Step S2. Measuring the linear displacement generated by the aerospace mechanical servo actuator by means of a linear displacement sensor (3), and measuring the number of rotations of the motor (2) by means of a rotary transformer (7); Step S3. Connecting the upper support ear (1) and the lower support ear (6) to the load through the mounting interface to drive the load to move; Step S4. The servo actuator converts the rotation of the motor (2) into the telescopic movement of the ball screw (4) without any load. Step S5. When the servo actuator is subjected to an axial load, the deformation of the lead screw, bearings, screws and related structural parts may cause a deviation in the relationship between the elongation δ of the ball screw (4) and the number of rotations n of the motor (2); Step S6. To ensure that the output torque of the motor (2) is maximized, the control system uses a direct-axis current i d =0 mode control; Step S7. The elongation of the ball screw (4) is measured in real time by the displacement sensor (3) provided in the electromechanical actuator, and the number of revolutions of the motor (2) is measured in real time by the rotary transformer (7) at the rear end of the motor (2).

2. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: In step S4, the elongation of the ball screw (4) and the number of rotations of the motor (2) follow the following relationship: δ=n×P# Where, δ′ is the elongation of the ball screw (4) when subjected to axial load, n is the number of revolutions of the ball screw (4), P is the lead of the ball screw (4), and F 丝杠 is the axial load on the ball screw (4), and K is the stiffness of the electromechanical actuator.

3. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: In step S5, the elongation of the ball screw (4) and the number of rotations of the motor (2) follow the following relationship: Wherein, δ' is the elongation of the ball screw (4) when subjected to axial load, n is the number of revolutions of the motor (2), P is the lead of the ball screw (4), and F 丝杠 is the axial load on the ball screw (4), and K is the stiffness of the electromechanical actuator.

4. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: The electromechanical servo actuator adopts a surface-mounted permanent magnet synchronous motor and has low requirements on the rotation speed.

5. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: In step S6, after the motor (2) is determined, the output torque is completely dependent on the quadrature axis current, that is: T 电机 =i q ×K t # In the formula, K t is the torque coefficient of motor (2), which is the basic parameter of motor (2) and is a fixed value when working under normal circumstances. q is the quadrature axis current of the motor (2), which is the system feedback quantity and can be collected in real time.

6. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: In step S6, the output torque of the motor (2) and the output axial force of the ball screw (4) have the following relationship: In the formula, F 丝杠 is the axial force output by the ball screw (4), P is the lead of the ball screw (4), and γ is the transmission efficiency from the motor (2) to the ball screw (4); Type T 电机 =i q ×K t #Substitution In, we get: In integrated With The stiffness of the aerospace electromechanical servo actuator is obtained as: In the formula, i q is the quadrature axis current of the motor (2), K t is the torque coefficient of the motor (2), P is the lead of the ball screw (4), γ is the transmission efficiency from the motor (2) to the ball screw (4), δ' is the elongation of the ball screw (4) when it is subjected to an axial load, and n is the number of revolutions of the motor (2).

7. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 6, characterized in that: The i q is the system feedback quantity, which can be collected in real time. t is a basic parameter of the motor (2), which is a fixed value when working under normal circumstances. P is the lead of the ball screw (4), which is also a fixed value. The transmission efficiency γ is 0.

76.

8. The method for measuring the stiffness of an aerospace mechanical servo actuator according to claim 1, characterized in that: The electromechanical servo actuator adopts a linear servo actuator, comprising an upper lug (1), a motor (2), a linear displacement sensor (3), a ball screw (4), a housing (5), a lower lug (6) and a rotary transformer (7); the motor (2) is arranged inside the housing (5) at a rear end, the linear displacement sensor (3) is arranged on a front side of the housing (5), the output end of the motor (2) is connected to the ball screw (4), one end of the ball screw (4) extends outside the housing (5) and is connected to the lower lug (6); the upper lug (1) is fixedly connected to the rear end of the housing (5), and the rotary transformer (7) is arranged outside the motor (2).

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