CN108548670A - A kind of planetary roller screw pair driving error measurement method - Google Patents

Abstract

The invention discloses a method for measuring the transmission error of a planetary roller screw pair, which belongs to the technical field of transmission error measurement. Under the no-load condition, the planetary roller screw is installed in the test device, and each sensor is initialized. By inputting the speed command to the motor, the circular grating and the lead screw are driven to rotate synchronously, and the circular grating can measure the speed and rotation angle of the lead screw. The rotation of the lead screw drives the nut to move axially, and when the nut moves, the grating scale reading head moves with the measuring head to generate an axial displacement signal. The transmission error of the planetary roller screw is calculated by using the counting method and the transmission ratio of the planetary roller screw; under the loading condition, the experimental device is added with a loading device compared with the no-load condition. The hydraulic cylinder is the power source, and applies a given axial force to the sleeve fixed on the outside of the nut. The rest of the operations are similar to the no-load condition, and finally the transmission error of the planetary roller screw under a given axial force can be obtained.

Description

A method for measuring the transmission error of a planetary roller screw pair

technical field

The invention relates to the technical field of measurement methods for transmission errors, in particular to a method for measuring transmission errors of a planetary roller screw under no-load and loaded conditions.

Background technique

With the application and development of electromechanical actuators in military and civilian fields, actuators with high thrust, high precision, high frequency response, high efficiency and long life have become the development requirements, and the planetary roller screw with its high thrust and performance It is used in high-speed and relatively harsh environments, and is widely used in all-electric aircraft and weaponry, petrochemicals, CNC machine tools and other fields.

Transmission accuracy is one of the important indicators to evaluate the transmission performance of planetary roller screw. The basic performance indicators of the servo system are fast, accurate and stable. As the transmission mechanism in the electromechanical servo system, the transmission accuracy of the planetary roller screw has a great influence on the static and dynamic performance of the system. In the open-loop system, the insufficient precision of the planetary roller screw will increase the steady-state error of the system and directly affect the accuracy of the entire system; in the closed-loop control system, although the transmission accuracy of the planetary roller screw will not affect the accuracy of the system , but it will affect the dynamic performance of the system. Insufficient transmission accuracy of the planetary roller screw will increase the overshoot of the system and prolong the adjustment time, thus affecting the speed and accuracy of the control system.

The factors affecting the transmission accuracy of planetary roller screw are very complicated, and various errors coexist at the same time, so it is very difficult to calculate its value accurately. The transmission error data of the planetary roller screw system can be used to verify the correctness of the theoretical calculation and analysis of the planetary roller screw transmission error, and to determine the actual transmission accuracy of the planetary roller screw, so for the planetary roller screw transmission error The research analysis becomes very important.

Contents of the invention

Therefore, aiming at the above-mentioned problems in the prior art, the present invention proposes a method for measuring the transmission error of the planetary roller screw under no-load and loaded conditions.

Specifically, under no-load conditions, the method includes:

Step 1: Install the planetary roller screw to be tested on the test bench, and initialize the circular grating and grating scale;

Step 2: Input the speed command through the motor, the motor drives the drive shaft through the mechanical transmission device, the circular grating is installed on the drive shaft, and the drive shaft drives the measured screw and the circular grating to rotate synchronously, and the read signal generates an angle reference signal, the wire When the bar rotates, it drives the nut to move in the axial direction. When the nut moves, the grating reading head moves with the measuring head to generate an axial displacement signal. The high-speed counting card is used to collect the signals of the circular grating and the grating ruler at the same time. After the high-speed counting card receives the signals of the grating and the grating ruler Perform high-magnification electronic subdivision and transfer to the computer;

Step 3: Use the signal obtained in step 2 to calculate the angle that the screw turns, which is the input angle; convert the angle of the screw into the theoretical displacement of the nut through the transmission ratio relationship; then measure the nut in real time under the input angle through the grating ruler The actual displacement; finally, the real-time comparison of the difference between the actual displacement and the theoretical displacement is the transmission error of the planetary roller screw.

Further, in step 1 of the method, the planetary roller screw to be tested is installed on the test bench in an installation manner in which one end is fixed and the other end is free.

Further, step 1 of the method also includes: checking whether the parameter setting of the measurement and control system is normal and ensuring that normal testing and control can be carried out; OK, while determining the starting position of the planetary roller screw movement for the measurement.

Under loading conditions, the method includes:

Step 1: Install the planetary roller screw to be tested on the test bench. The test bench is equipped with a loading device, and the planetary roller screw is axially loaded by hydraulic loading, and the hydraulic cylinder is used as the power source to realize it through a composite controller. To adjust the loading force, connect a force sensor at the output end of the hydraulic cylinder, add a force cycle control system to the computer measurement and control program, and initialize the circular grating and grating ruler;

Step 2: Input the load command and control the hydraulic cylinder through the composite controller. At the same time, the tension and pressure sensor at the output end of the hydraulic cylinder performs feedback adjustment on the composite sensor to obtain a reliable axial input load of the planetary roller screw and act on it through the sleeve. On the nut, the rotation speed command is input by the motor, and the circular grating is installed on the drive shaft. The drive shaft drives the measured screw and the circular grating to rotate synchronously, and the read signal generates an angle reference signal. When the screw rotates, it drives the nut to move axially. When the nut moves, the grating reading head moves with the measuring head to generate an axial displacement signal. The high-speed counting card is used to collect the signals of the circular grating and the grating ruler at the same time. ;

Step 3: Use the signal obtained in step 2 to calculate the angle that the screw turns, which is the input angle; convert the angle of the screw into the theoretical displacement of the nut through the transmission ratio relationship; then measure the nut in real time under the input angle through the grating ruler The actual displacement; finally, the real-time comparison of the difference between the actual displacement and the theoretical displacement is the transmission error of the planetary roller screw.

The motion of the planetary roller screw at the fixed end is more stable when an axial load is applied. Therefore, data collection is carried out at the stroke section close to the fixed end of the screw to improve the accuracy of measurement.

Further, in step 1 of the method, the planetary roller screw to be tested is installed on the test bench in an installation manner in which one end is fixed and the other end is free.

Further, step 1 of the method also includes: checking whether the parameter setting of the measurement and control system is normal and ensuring that normal testing and control can be carried out; OK, while determining the starting position of the planetary roller screw movement for the measurement.

The technical effect of the present invention is that the present invention proposes a method for measuring the transmission error of the planetary roller screw pair, which realizes the accurate measurement of the transmission error of the planetary roller screw pair under no-load and loaded conditions. Compared with the measuring method in the prior art, the measuring method of the present invention is faster and more accurate.

Description of drawings:

Fig. 1 is a schematic diagram of the transmission error measurement system in embodiment 1 under the no-load working condition.

Fig. 2 is a schematic diagram of the transmission error measurement system under the loading condition of embodiment 2.

Detailed ways

The specific embodiment of the present invention is described below:

Example 1

The method for measuring the transmission error of a planetary roller screw includes the following steps:

Measurement of transmission error under no-load condition:

Step 1: As shown in Figure 1, it is to measure the transmission accuracy of planetary roller screws with different lengths and different diameters under the same experimental device. In this measurement method, one end is fixed and the other end is free. The column screw is installed on the test bench to initialize the circular grating 2 and the grating scale 4, and check whether the parameter settings of the measurement and control system are normal to ensure normal testing and control. Slowly run-in the planetary roller screw 3, observe whether the experimental system is operating normally, and determine the starting position of the reciprocating motion of the planetary roller screw 3 at the same time.

Step 2: After the measurement system works normally, input the speed command through the motor 1. The motor drives the drive shaft through the mechanical transmission device, and the circular grating 2 is installed on the drive shaft. During measurement, the drive shaft drives the measured screw 301 and the circular grating 2 to rotate synchronously, and the read signal generates an angle reference signal. When the lead screw 301 rotates, it drives the nut 302 to move in the axial direction, and when the nut 302 moves, the grating reading head moves with the measuring head to generate an axial displacement signal. In order to measure the accurate value of the transmission error, the system must ensure that the angular reference displacement signal and the axial displacement signal are collected synchronously. Therefore, a high-speed counting card 5 is used to simultaneously collect the signals of the circular grating 2 and the grating scale 4. The counting card receives the circular grating 2 and the grating High-magnification electronic subdivision is carried out after the signal of ruler 4 to obtain high-precision data and transmit it to computer 6 for analysis and calculation.

Step 3: According to the measurement principle of the counting method, convert the obtained pulse signal into the angle that the lead screw rotates, which is the input rotation angle; secondly, convert the rotation angle of the lead screw into the theoretical displacement of the nut through the transmission ratio relationship; and then pass the grating ruler The actual displacement of the nut under the input rotation angle is measured in real time; finally, the difference between the actual displacement and the theoretical displacement is compared in real time, which is the transmission error of the planetary roller screw. The circular grating generates N angular pulse signals every time the screw rotates. When the screw rotates through M angular pulse signals, it turns M/N, and the angle that the screw rotates within this time period is 2πM/N . According to the transmission principle of the planetary roller screw, the lead L _S of the screw is the axial movement distance of the nut when the screw rotates once. When the lead screw 301 rotates through M angular pulses, the theory of the nut 302 is S _t =2πML _S /N. Then measure the actual displacement S _p of the nut 302 under the input rotation angle in real time through the grating ruler 4; finally, compare the difference between the actual displacement S _t and the theoretical displacement S _p in real time, which is the transmission error of the planetary roller screw Δ=S _{t -Sp} .

Example 2

As shown in FIG. 2 , the experimental device under the loading condition has a loading device 7 added compared with the no-load condition. The planetary roller screw 3 is axially loaded by means of hydraulic loading, the hydraulic cylinder 703 is used as the power source, and the loading force is adjusted through the composite controller 704 . A force sensor 701 is connected to the output end of the hydraulic cylinder, and a force feedback adjustment 702 is added to the measurement and control program to reduce interference to the data acquisition system.

The motion of the planetary roller screw 3 at the fixed end is more stable when an axial load is applied. Therefore, data collection is performed at a travel section close to the fixed end of the lead screw 301 to improve measurement accuracy.

The first step: the same as the first step under the no-load condition.

Step 2: Input the load index 705 and control the hydraulic cylinder 703 through the composite controller 704. At the same time, the pull pressure sensor 701 at the output end of the hydraulic cylinder can adjust the composite controller 704 through the force feedback adjustment 702 to obtain a reliable planetary rolling. The column screw axially inputs load and acts on the nut 302 through the sleeve 303 . Slowly load the end of the nut 302 to the initial loading force. After the hydraulic pressure 701 stabilizes, give the servo motor 1 a working speed command, and the rest of the operations are the same as the second step in the no-load condition.

The third step: the same as the third step under the no-load condition. The final difference between the actual displacement S _t and the theoretical displacement S _p is the transmission error Δ=S _t -S _p under the action of the axial load in the second step in the measurement under the loading condition.

The above are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be regarded as protection of the invention.

Claims (6)

1. a kind of planetary roller screw pair driving error measurement method, which is characterized in that the method includes：

Step 1：Planetary roller screw to be measured is installed on experimental bench, Circular gratings, grating scale are initialized；

Step 2：It is instructed by motor input speed, motor drives drive shaft, Circular gratings device to be mounted on by mechanical driving device It in drive shaft, is driven by drive shaft and is tested leading screw and Circular gratings synchronous rotation, read signal and generate angle reference signal, leading screw turns Nut is driven to be axially moveable when dynamic, grating reading head moves with measurement head and generates axial displacement signal when nut moves, and uses High-speed counting card acquires the signal of Circular gratings and grating scale simultaneously, and high-speed counting clamping carries out height after receiving grating and grating scale signal It is electronic fine-grained again and be transferred to computer；

Step 3：The angle that leading screw turns over is calculated using signal obtained by step 2, as inputs corner；It will by gear ratio relation The corner of leading screw is converted into the theoretical displacement of nut；Measure reality of the nut under the input corner in real time by grating scale again Displacement；Finally, the difference of real time contrast's actual displacement and theoretical displacement is the driving error of planetary roller screw.

2. planetary roller screw pair driving error measurement method as described in claim 1, which is characterized in that the method step It takes one end to fix the free mounting means in one end in one and planetary roller screw to be measured is installed on experimental bench.

3. planetary roller screw pair driving error measurement method as claimed in claim 2, which is characterized in that the method step Further include in one：Check whether TT＆C system parameter setting is normal and guarantees normally to be tested and controlled, normal work After work, slowly running-in is carried out to planetary roller screw, planet when observing and measuring whether system works well, while determining measurement The initial position of roller screw movement.

4. a kind of planetary roller screw pair driving error measurement method, which is characterized in that the method includes：

Step 1：Planetary roller screw to be measured is installed on experimental bench, loading device is arranged in testing stand, using hydraulic loaded mode It is axially loaded to planetary roller screw progress, using hydraulic cylinder as power source, loading force size is realized by composite controller Adjustment connects force snesor in hydraulic cylinder output end, power cyclic control system is added in computer measurement and control program, to circle light Grid, grating scale are initialized；

Step 2：Input load instructs and controls hydraulic cylinder, while the pressure of the output end of hydraulic cylinder by composite controller Sensor carries out feedback regulation to compound sensor, to obtain reliable planetary roller screw axial direction input load and pass through sleeve It acts on nut, is instructed by motor input speed, Circular gratings device is installed on the driving shaft, is driven by drive shaft and is tested leading screw It is rotated synchronously with Circular gratings, reads signal and generate angle reference signal, drive nut to be axially moveable when leading screw rotates, nut moves Grating reading head moves with measurement head and generates axial displacement signal when dynamic, and Circular gratings and grating are acquired simultaneously using high-speed counting card The signal of ruler, high-speed counting clamping receive that high power is carried out after grating and grating scale signal is electronic fine-grained and be transferred to computer；

Step 3：The angle that leading screw turns over is calculated using signal obtained by step 2, as inputs corner；It will by gear ratio relation The corner of leading screw is converted into the theoretical displacement of nut；Measure reality of the nut under the input corner in real time by grating scale again Displacement；Finally, the difference of real time contrast's actual displacement and theoretical displacement is the driving error of planetary roller screw.

5. planetary roller screw pair driving error measurement method as claimed in claim 4, which is characterized in that the method step It takes one end to fix the free mounting means in one end in one and planetary roller screw to be measured is installed on experimental bench.

6. planetary roller screw pair driving error measurement method as claimed in claim 5, which is characterized in that the method step Further include in one：Check whether TT＆C system parameter setting is normal and guarantees normally to be tested and controlled, normal work After work, slowly running-in is carried out to planetary roller screw, planet when observing and measuring whether system works well, while determining measurement The initial position of roller screw movement.