WO2020252875A1

WO2020252875A1 - Simple pendulum apparatus and rapid oscillation control method thereof

Info

Publication number: WO2020252875A1
Application number: PCT/CN2019/100800
Authority: WO
Inventors: 李朝峰; 张子健; 李培勇; 乔瑞环
Original assignee: 东北大学
Priority date: 2019-06-18
Filing date: 2019-08-15
Publication date: 2020-12-24
Also published as: CN110377061B; CN110377061A

Abstract

A simple pendulum apparatus and a rapid oscillation control method thereof. A simple pendulum structure of the simple pendulum apparatus is connected to a mounted bearing (1) by means of a connection apparatus (3). A rotation angle of the simple pendulum structure is converted into an analog signal by means of a photoelectric encoder (13), and a computer (17) acquires and stores the analog signal. A moving slider (9) is connected to a stepping motor (4) by means of a synchronous belt (6) and a synchronous pulley (18), and the stepping motor (4) controls movement of the moving slider on the simple pendulum structure. The rapid oscillation control method comprises the following steps: acquiring and determining an oscillation angle of the simple pendulum in real time; and when the simple pendulum reaches a maximum angle, controlling the moving slider (9) to move upwards, and when the simple pendulum reaches a vertical position, controlling the moving slider (9) to move downwards. A method for controlling movement of the moving slider (9) is designed, and a movement distance ΔL for each movement of the moving slider (9) is designed. The simple pendulum apparatus and the control method efficiently and stably control oscillation, and are applicable to the field of rapid suppression of oscillation of a simple pendulum structure.

Description

Single pendulum device and its rapid swing control method

Technical field

The invention belongs to the field of mechanical structure swing control, in particular to a single pendulum device and a rapid swing control method thereof.

Background technique

At present, pendulum structures are widely used in construction, agriculture, aerospace and other fields, such as cranes, tethered drones, and tethered satellites. However, the swing of these structures has a great adverse effect on the equipment. Existing swing control methods for simple pendulum structures often take up a lot of space and have low swing suppression efficiency.

Summary of the invention

(1) Technical problems to be solved

Aiming at the swing control problem of a simple pendulum structure in the prior art, the present invention provides a swing control device and a control method thereof with high versatility and high swing control efficiency.

(2) Technical solution

In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

A single pendulum device, which includes a supporting system, a bearing with a seat, a photoelectric encoder, a rotating shaft, a connecting device, a stepping motor, a single pendulum structure, a moving slider, and a control and acquisition system;

The seated bearing is arranged on the supporting system through the bearing seat, and the rotating shaft is fixedly connected with the bearing inner ring of the seated bearing;

The pendulum structure is fixedly connected with the rotating shaft through the connecting device;

The moving slider is slidably connected with the pendulum structure and slides under the drive of a stepper motor. The swing of the pendulum can be quickly suppressed by the movement of the moving slider on the pendulum structure;

The rotating shaft of the photoelectric encoder is connected with the rotating shaft;

The photoelectric encoder and stepper motor are connected to the control and acquisition system for communication.

Preferably, the pendulum device includes an upper bracket and a lower bracket that are arranged oppositely;

An optical axis is fixedly arranged between the upper bracket and the lower bracket, and the movable slider is slidably connected with the optical axis.

Preferably, the upper bracket is provided with a first timing belt wheel, the lower bracket is provided with a second timing belt wheel, the first timing belt wheel and the second timing belt wheel are wound with timing belts, and the moving slider is fixedly connected to the timing belt. ；

The first synchronous belt wheel is fixedly connected with the output shaft of the stepping motor, the stepping motor drives the synchronous belt to move through the first synchronous belt wheel, and the synchronous belt drives the slider to move on the single pendulum.

Preferably, the photoelectric encoder is connected to the control and acquisition system through a data acquisition card;

The swing angle of the pendulum structure measured by the photoelectric encoder is input to the control and acquisition system through the data acquisition card.

Preferably, the control and acquisition system will control the rotation of the stepping motor according to the swing control method.

A method for quickly controlling the swing of a single pendulum, which is used for controlling the operation of the above-mentioned single pendulum device. It is an intermittent motion control method that moves the slider. The control method can not only use the swing suppression effect generated by the sliding of the moving slider on the pendulum structure to perform rapid control of the pendulum swing, but also reduce the disturbance of the pendulum device near the stable position during actual swing. The algorithm can be implemented without establishing a specific mathematical model of the structure, and specifically includes the following steps:

Step 1: Collect the swing angle of the pendulum in real time and determine the time when it swings to the maximum angle and the minimum angle (the pendulum vertical position);

Step 2: When the pendulum swings to the maximum angle, control the moving slider to move upward; when the pendulum swings to the minimum angle, control the moving slider to move downward;

Step 3: Determine the movement distance of each movement of the moving slider according to the automatic control method.

Preferably, in step 1, the simple pendulum device is allowed to swing freely from a certain initial angle θ ₀ , and the photoelectric encoder is used to collect the angle θ of the simple pendulum in real time, and determine the maximum angle and the minimum angle to trigger the rotation of the stepping motor Thereby driving the moving slider to move.

Preferably, in step 2, when the computer recognizes that the single pendulum reaches the maximum angle, the stepping motor control card will control the stepping motor to make the moving slider move upwards, wherein the upward movement track of the slider is:

When the computer recognizes that the single pendulum reaches the minimum angle, the stepper motor control card will control the stepper motor to move the moving slider downwards, where the downward movement track of the slider is:

Among them, i=1, 2, 3... represents the sequence of upward and downward movement.

Preferably, in step 2, ΔT is the movement time of each movement of the moving slider, and it is required to be less than a quarter of the swing period of the single pendulum to ensure rapid suppression of the swing of the single pendulum; ΔL is the time required for each movement of the moving slider. Movement distance.

Preferably, in step 2, considering that the actual movement of the moving slider requires an acceleration and deceleration process, the cosine trajectory is adopted as the moving trajectory of the moving slider.

Preferably, in step 2, it should be noted that only the form of the movement track of the moving slider is given, and the specific movement position needs to be determined according to the set initial position of the slider and the position after each movement. In the formula l ₀ , the position after each movement is the starting position of the next movement.

Preferably, in step 3, the movement distance ΔL for each upward and downward movement of the design moving slider is calculated according to the control method, and the expression is

Among them, ΔL _max is the maximum range of the movable slider; e is the natural base;

Is the maximum swing that a single pendulum can reach per cycle; in order to measure the speed of the swing suppression of the single pendulum, set θ _sta as the attenuation standard of the single pendulum swing, that is, the time when the single pendulum swings to θ _sta is used as a comparison of the influence of different parameters Standard; λ and ε are control parameters to adjust the change of motion range.

Preferably, in step three, the control parameter

Its function is to maximize the movement distance at the initial swing angle no matter how much λ is taken, thereby producing a better swing suppression effect.

Preferably, in step 3, after setting the parameters, it can be predicted in advance that the moving distance of the moving slider is decreasing until ΔL is 0 when the pendulum does not move, so as to ensure the stability of the pendulum device movement.

(3) Beneficial effects

The beneficial effects of the present invention are: the present invention provides a single pendulum device and a control method for rapid control of the swing of the single pendulum. The computer collects the angle signal of the simple pendulum to trigger the rotation of the stepper motor to drive the movement of the moving slider. The proposed simple pendulum structure with a moving slider has a certain general applicability; the proposed control method does not require an accurate mathematical model of the device, and can be used only by judging the maximum and minimum of the angle of the simple pendulum. Applicability and higher swing control efficiency.

Description of the drawings

Figure 1 is a schematic diagram of a simple pendulum device;

Figure 2 is a schematic diagram of the upper bracket of the single pendulum structure;

Figure 3 is a schematic diagram of the lower bracket of the single pendulum structure;

Figure 4 is a schematic diagram of a quick control method for the swing of a simple pendulum;

Figure 5 is a schematic diagram of the angular response of the swing of a simple pendulum structure.

among them:

1: Bearing with seat; 2: Rotating shaft; 3: Connecting device; 4: Stepping motor; 5: Upper bracket; 6: Timing belt; 7: Optical axis; 8: Table; 9: Moving slide; 10: Lower bracket 11: horizontal support board; 12: first vertical support board; 13: photoelectric encoder; 14: second vertical support board; 15: data acquisition card; 16: stepper motor control card; 17: processor.

Detailed ways

In order to better explain the present invention and facilitate understanding, the present invention will be described in detail below with reference to the accompanying drawings and through specific embodiments.

As shown in Figure 1, this implementation provides a single pendulum device, which includes: a control and acquisition system, a support system, a bearing 1, a photoelectric encoder 13, a rotating shaft 2, a connecting device 3, a stepping motor 4, a single Pendulum structure and moving slider 9.

The control and acquisition system includes a data acquisition card 15, a stepping motor control card 16, and a processor 17, where the processor is a computer.

The supporting system includes a supporting structure and a table 8. The supporting structure includes two vertical supporting plates and a horizontal supporting plate 11. The two vertical supporting plates are a first vertical supporting plate 12 and a second vertical supporting plate 14 respectively. The two vertical support plates are arranged symmetrically. The horizontal support plate 11 is arranged at the upper end of the vertical support plate. The lower ends of the two vertical support plates are fixed in the T-shaped groove on the table 8 by T-bolts. The support plate is fixed by bolts.

The bearing seat of the seated bearing 1 and the horizontal support plate 11 are connected and fixed by bolts, and the bearing inner ring of the seated bearing 1 and the rotating shaft 2 are fixed by an expansion sleeve.

The connecting device 3 includes front and rear connecting plates. One end of the connecting plate is fixedly connected to the rotating shaft through an expansion sleeve, and the other end is fixedly connected to the pendulum structure. The rotating shaft 2, the connecting device 3 and the bearing inner ring of the seated bearing 1 The single pendulum structure swings together.

The photoelectric encoder 13 adopts the OMRON 3600P/R photoelectric encoder, which is fixed on the supporting system and connected to the shaft 2. The photoelectric encoder 13 is connected to the computer 17 through the data acquisition card 15, and the photoelectric encoder 13 is used for real-time measurement of pendulums. The angle of the structure swing, and the collected angle information is transmitted to the computer 17 through the data acquisition card 15.

The single pendulum structure includes two optical shafts 7, an upper bracket 5 and a lower bracket 10.

FIG. 2 is a schematic diagram of the structure of the upper bracket. The upper bracket 5 also serves as the bracket of the stepping motor 4, and the stepping motor 4 is fixed on the upper bracket 5. The upper bracket 5 is connected and fixed to the connecting device 3 by two bolts, and the upper bracket 5 and the connecting device 3 can swing together. The upper bracket 5 is provided with a first timing belt wheel 18, and the upper bracket 5 and the two optical shafts 7 are fixedly connected by an expansion sleeve.

Fig. 3 is a schematic diagram of the structure of the lower bracket. The lower bracket 10 is provided with a second timing pulley 19, and the other ends of the lower bracket 10 and the two optical shafts 7 are also fixedly connected by an expansion sleeve.

The moving slider 9 is sleeved on the optical axis 7 and can slide relative to the optical axis 7. The moving slider 9 is fixedly connected with the timing belt 6, and the two ends of the timing belt 6 respectively bypass the first timing pulley 18 and the second timing pulley 19, that is, the timing belt 6 is sleeved on the first timing pulley 18 and the second timing pulley. Synchronous pulley 19 on.

The output shaft of the stepping motor 4 is connected to the first timing belt wheel 18. The stepping motor 4 drives the rotation of the first timing belt wheel 18, the first timing belt wheel 18 drives the timing belt 6 to move, and the moving sliding block 9 follows the timing belt. 6 mobile.

The movable sliding block 9 includes two linear bearings, and the movable sliding 9 is sleeved on the optical axis 7 through the linear bearings. Therefore, the movable sliding block 9 can move smoothly and quickly on the two optical axes 7.

The specific motion form of the moving slider 9 is determined by the control method proposed by the present invention.

Specifically, in this embodiment, a rapid control method for the swing of a single pendulum is provided, which is an intermittent control method for moving a slider. The method proposed by the present invention combines active control with automatic control, actively controls the overall movement process of the moving slider, and automatically controls the movement distance of the moving slider.

The advantage of this method is that the active control method proposed by the present invention can utilize the intermittent movement of the moving slider to achieve rapid suppression of the pendulum swing, and the automatic control method can reduce the disturbance of the pendulum device near the stable position during actual swing. Moreover, the algorithm proposed by the present invention can realize rapid control of swing without establishing a mathematical model with precise structure.

A rapid control method for swinging of a single pendulum, the method includes the following steps:

Step 1: Collect the swing angle of the pendulum in real time and determine the time when the pendulum swings to the maximum angle and the minimum angle (the minimum angle refers to when the pendulum is in the vertical position).

Make the pendulum device swing freely from a certain initial angle θ ₀ , use the photoelectric encoder to collect the angle θ of the pendulum in real time, and compare the angles collected at each sampling point by the computer to determine the maximum angle and Minimum angle. When the simple pendulum reaches the maximum and minimum angles, the computer will issue instructions to control the rotation of the stepper motor to drive the moving slider.

When the computer recognizes that the single pendulum reaches the maximum angle, it will send a control instruction to the stepper motor control card to control the stepper motor to move the moving slider upward, and the trajectory of the upward movement

Determined by the control method shown in formula (1).

When the computer recognizes that the single pendulum reaches the minimum angle, the stepper motor control card will control the stepper motor to make the moving slider move downward, and the trajectory of the downward movement of the slider

Determined by the control method shown in formula (2).

In equations (1) and (2), i=1, 2, 3... represents the order of upward and downward movement;

with

They are the maximum and minimum moments of the pendulum angle recognized by the computer, which are the starting moments of the upward and downward movement of the moving slider; ΔT is the movement time of each movement of the moving slider, and it is required to be less than the swing of the pendulum A quarter of the period is used to ensure the rapid control of the pendulum swing; ΔL is the movement distance of the moving slider, which needs to be further calculated by the control method.

The present invention takes into account that the actual movement of the moving slider needs to have acceleration and deceleration processes, so the cosine trajectory is used as the moving trajectory of the moving slider, and the movement speed is to start from 0 to accelerate the movement to a certain speed and then decelerate to 0. At the same time, it should be noted that it is also necessary to determine l ₀ according to the set initial position of the slider and the position after each movement to determine the specific movement position of the moving slider. The position after each movement is the starting position of the next movement and does not need to be specified in advance.

Step 3: Determine the movement distance ΔL of each movement of the moving slider according to the automatic control method.

Taking into account the stability of the swing of the whole device when the pendulum is close to the stable position, the moving distance ΔL of each upward and downward movement of the moving slider designed by the present invention will be calculated according to the control method, and its expression is

Among them, ΔL _max is the maximum range of movement available for the movable slider; e is the natural base;

It is the maximum swing that a single pendulum can reach per cycle; in order to measure the attenuation speed of the single pendulum, set θ _sta as the attenuation standard of the single pendulum swing, that is, the time when the single pendulum swings to θ _sta is used as a comparison of the influence of different parameters Standard; λ and ε are both control parameters to adjust the change of motion range.

Preferably, in step 3, the function of the control parameter λ is to control the speed at which the movement range of the moving slider decreases.

Preferably, in step three, the control parameter

Preferably, in step 3, after the parameters are given, it can be predicted in advance that the moving distance of the moving slider will decrease until ΔL is 0 when the pendulum does not move, so as to ensure the stable movement of the pendulum device. Sex.

Preferably, in step 3, in order to better understand the movement distance ΔL of the moving slider, Figure 4 shows the intermittent movement of the moving slider during the first two cycles of the pendulum swing, where the first cycle of the pendulum swing includes two There are two downward movements of the slider and one upward movement of the slider. The second cycle and each subsequent cycle include two upward and downward movements of the mass.

In the following, a specific experimental example is combined to further illustrate the effectiveness and efficiency of the present invention on the rapid control of the pendulum swing.

The actual measured parameters of the pendulum structure are as follows:

M = 1.151 kg, m = 0.156 kg, L = 1.059 m, L _c = 0.3726 m, I ₀ = 0.326 kg·m ²

Set the initial conditions of the pendulum swing: θ ₀ =0.5rad, θ _sta =0.05rad, specify the rapid control method of the pendulum swing and the parameters in the motion track of the moving slider as follows:

ΔT=0.28s, ΔL _max =0.06m, λ=2, l ₀ =0.8m.

The comparison between the angular response of the pendulum structure under the control method and control process and the angular response when the moving slider does not move (the pendulum swings freely) is shown in Figure 5. It can be seen from FIG. 5 that the simple pendulum structure with a moving slider and its rapid control method for swing control proposed by the present invention reach θ _sta 70.86s earlier under the selected parameters, which can achieve higher swing control efficiency. The swing suppression efficiency produced by the rapid swing control method proposed by the present invention will increase as the movement time ΔT of the moving slider decreases and the movement distance ΔL increases. Therefore, in practical applications, it is necessary to reasonably set the movement time and movement distance according to the parameters that the device can achieve to achieve more efficient swing suppression.

The technical principles of the present invention are described above in conjunction with specific embodiments. These descriptions are only for explaining the principles of the present invention and cannot be construed as limiting the protection scope of the present invention in any way. Based on the explanation here, those skilled in the art can think of other specific implementation manners of the present invention without creative work, and these manners will fall within the protection scope of the present invention.

Claims

A single pendulum device, which is characterized in that it comprises a support system, a bearing with a seat, a photoelectric encoder, a rotating shaft, a connecting device, a stepping motor, a single pendulum structure, a moving slider, and a control and acquisition system;

The seated bearing is arranged on the supporting system through the bearing seat, and the rotating shaft is fixedly connected with the bearing inner ring of the seated bearing;

The pendulum structure is fixedly connected with the rotating shaft through the connecting device;

The moving slider is slidably connected with the pendulum structure and slides under the drive of a stepper motor. The swing of the pendulum can be quickly suppressed by the movement of the moving slider on the pendulum structure;

The rotating shaft of the photoelectric encoder is connected with the rotating shaft;

The photoelectric encoder and stepper motor are connected to the control and acquisition system for communication.
The single pendulum device according to claim 1, wherein the single pendulum device comprises an upper bracket and a lower bracket which are arranged oppositely;

An optical axis is fixedly arranged between the upper bracket and the lower bracket, and the movable slider is slidably connected with the optical axis.
The single pendulum device according to claim 2, wherein the upper bracket is provided with a first timing belt wheel, the lower bracket is provided with a second timing belt wheel, and the first timing belt wheel and the second timing belt wheel are wound on There is a timing belt, the moving slider is fixedly connected with the timing belt;

The first synchronous belt wheel is fixedly connected with the output shaft of the stepping motor, the stepping motor drives the synchronous belt to move through the first synchronous belt wheel, and the synchronous belt drives the slider to move on the single pendulum.
The simple pendulum device according to claim 3, wherein the photoelectric encoder is connected to the control and acquisition system through a data acquisition card;

The swing angle of the pendulum structure measured by the photoelectric encoder is input to the control and acquisition system through the data acquisition card.
The single pendulum device of claim 4, wherein the control and acquisition system will control the rotation of the stepping motor according to the swing control method.
A rapid control method for the swing of a single pendulum, characterized in that the method is used to control the operation of the single pendulum device according to any one of claims 1-5, and the algorithm includes the following steps:

Step 1: Collect the swing angle of the pendulum in real time and determine the moment when the swing reaches the maximum angle and the minimum angle;

Step 2: When the pendulum swings to the maximum angle, control the moving slider to move upward; when the pendulum swings to the minimum angle, control the moving slider to move downward;

Step 3: Determine the movement distance of each movement of the moving slider according to the control method.
The rapid swing control method according to claim 6, wherein in step one, the pendulum is allowed to swing freely from a certain initial angle and the swing angle of the pendulum is collected in real time.
The rapid swing control method according to claim 6, wherein in step 2, when the single pendulum reaches the maximum angle, the upward movement trajectory of the slider is:

When the simple pendulum reaches the minimum angle, the downward movement track of the slider is:

Among them, i=1, 2, 3... represents the sequence of upward and downward movement, ΔT is the movement time of each movement of the moving slider; ΔL is the movement distance of each movement of the moving slider.
The method for rapid swing control according to claim 8, wherein the movement time of each movement of the moving slider is less than a quarter of the swing period of the simple pendulum.
The method for rapid swing control according to claim 6, characterized in that, in step 3, the moving distance of each upward and downward movement of the slider is obtained according to the following expression:

Among them, ΔL max is the maximum range of the movable slider; e is the natural base;
Is the maximum swing that a single pendulum can reach per cycle; in order to measure the speed of the swing suppression of the single pendulum, set θ sta as the attenuation standard of the single pendulum swing, that is, the time when the single pendulum swings to θ sta is used as a comparison of the influence of different parameters Standard; λ and ε are control parameters to adjust the change of motion range.