CN108818539A - A kind of flexible motion arm elastic vibration Active Disturbance Rejection Control device and method - Google Patents

Abstract

The invention discloses a flexible operating arm elastic vibration active disturbance rejection control device and method. The control device includes a flexible operating arm, an end load, an image acquisition device, a positioning base, a motor transmission device, a motor driver, a bolt connection system, a motion control card, elastic vibration active disturbance rejection controller, frequency calculation module, signal processing module Ⅰ, signal processing module Ⅱ, signal acquisition device Ⅰ, signal acquisition device Ⅱ, based on the frequency calculation module, the frequency signal of the flexible manipulator arm during operation can be obtained in real time, The elastic vibration active disturbance rejection controller can change the control signal in real time to drive the positioning base to move, and then bring the flexible operating arm to a designated position; the invention also discloses a flexible operating arm elastic vibration active disturbance rejection control method; the invention can Fully considering the boundary effect of the flexible manipulator during the operation process, the active disturbance rejection control of the elastic vibration of the flexible manipulator is realized, which has the advantages of simple control structure and high robustness.

Description

Elastic vibration active disturbance rejection control device and method for a flexible manipulator

technical field

The invention relates to the technical field of robot flexible manipulating arm control, in particular to a flexible manipulating arm elastic vibration active disturbance rejection control device and method.

Background technique

At present, on the assembly line of the electronic packaging industry, space robot equipment mainly assembled by mechanical manipulators can be found everywhere. These devices are structurally in the form of bottom positioning bases and end actuators, such as placement machines, solder paste, etc. Printing machines, dispensing machines, etc. With the rapid development of the national economy, modern integrated circuit packaging operations require faster and faster response speeds and higher integration levels of mechanical systems. Traditional rigid manipulators have been difficult to meet the requirements of this development.

In recent years, with the in-depth study of flexible multibody dynamics theory and the practical needs of engineering, flexible manipulators have gained more and more attention. Compared with rigid manipulators, flexible manipulators have the advantages of light weight, high speed, high load-to-weight ratio, and modularization. However, the high-speed movement and light weight of the machine put forward higher requirements for the flexible manipulator. The main problem is that due to the structural characteristics of low stiffness and large deflection, the flexible manipulator is prone to elastic vibration during the movement process, and due to the flexibility The modal frequency of the manipulator is low, and the vibration will last for a long time, seriously affecting the operating efficiency of the robot system.

Therefore, in order to realize the effective use of the flexible manipulator on the robot, it is first necessary to effectively control the elastic vibration of the flexible manipulator. The closed-loop feedback control system considering the elastic vibration of the flexible manipulator needs to set up an additional active control system, which will lead to a complex structure of the overall system and increase the cost of the whole machine. Many scholars have studied the feedforward control method of mechanical elastic vibration.

For example, the invention patent with the Chinese patent number CN201510916217.1 discloses a crane anti-sway control method based on the positive and negative POSICAST input shaping method, and uses the input shaping method to construct a feedforward controller to realize the anti-sway control of the crane. The advantages of this method are There is no need for measuring sensors for closed-loop feedback, which simplifies the system structure, but this method does not consider the influence of the load on the vibration characteristic parameters of the crane system during the operation process.

Another example is the Chinese Patent No. CN201710975489.8, which discloses a method for suppressing residual vibration at the end of a robot joint based on an input shaper. The input shaping method is used to suppress the residual vibration at the end of a robot joint, but this method also does not consider The influence of end load mass and boundary effect on the characteristic parameters of robot joint vibration.

However, the flexible manipulator of the robot has variable load conditions in the actual operation process. In addition, the assembly force between the root of the flexible manipulator and the positioning base may change under long-term operation. These will change the boundary conditions of the flexible manipulator, and then change its The characteristic parameters such as the modal frequency itself lead to the failure of the feed-forward vibration controller designed based on the input shaping method in advance.

Therefore, in the actual operation process, it is necessary to fully consider the influence of the boundary effect of the flexible manipulator on its own modal characteristic parameters, and design the controller to realize the active disturbance rejection control of the elastic vibration of the flexible manipulator.

Contents of the invention

In order to avoid and solve the above-mentioned technical problems, the present invention proposes an elastic vibration active disturbance rejection control device and method for a flexible operating arm.

The technical problem to be solved by the present invention adopts the following technical solutions to realize:

A flexible operating arm elastic vibration active disturbance rejection control device, comprising: a flexible operating arm, the flexible operating arm is connected with a terminal load; an image acquisition device, to obtain the shape of the terminal load; a positioning base, the positioning base A motor transmission device is connected to the top; the bolt connection system connects the flexible operating arm and the positioning base and can sense pressure information; the motor transmission device is sequentially connected with a motor driver, a motion control card, an elastic vibration active disturbance rejection controller and a frequency calculation module, and the frequency calculation module is connected with a signal processing module I and a signal processing module II.

It also includes a signal acquisition device I connected with the bolt connection system and transmitting the pressure signal to the signal processing module I, and a signal acquisition device II connected with the image acquisition device and transmitting the signal to the signal processing module II.

Further, the motor transmission device includes a servo motor, the drive shaft of the servo motor is connected to a ball screw pair, and a coupling is provided at the connection between the ball screw pair and the servo motor, and the ball screw pair The nut is connected with the positioning base, and the positioning base is equipped with a moving guide rail.

Further, the bolt connection system includes: bolts passing through the positioning base and the flexible operating arm; nuts cooperating with the bolts; gasket II arranged at the joint between the bolts and the positioning base; The pressure sensor between; the gasket I is set between the pressure sensor and the nut.

Further, four sets of symmetrically distributed bolt connection systems are provided at the joint between the root of the flexible operating arm and the positioning base.

Further, the signal processing module II can output the quality of the end load in real time by using a preset work library according to the shape of the end load.

A control method for elastic vibration self-disturbance rejection of a flexible manipulator, comprising the following steps:

Step 1. Establish a working library in which the shape of a typical end load matches its own mass.

Step 2: Use the signal acquisition device I to collect the output signal of the pressure sensor in real time and transmit it to the signal processing module I, and the signal processing module I will process and obtain the matching pressure between the root of the flexible manipulator and the positioning base and transmit it to the frequency calculation module; at the same time, the signal The acquisition device II collects the output signal of the image acquisition device in real time and transmits it to the signal processing module II. According to the work library established in step 1, the signal processing module II processes and obtains the quality of the terminal load and transmits it to the frequency calculation module.

Step 3. Determine the real-time boundary conditions of the flexible manipulator according to the matching pressure between the root of the flexible manipulator and the positioning base and the quality information of the end load received by the frequency calculation module, and obtain the frequency equation of the flexible manipulator. Use the frequency calculation module to determine the flexibility The modal frequency of the manipulator.

Step 4: Design the elastic vibration active disturbance rejection controller, and determine the displacement control signal of the positioning base.

Step 5, using the motion control card and the motor driver to drive the positioning base to move, so that the flexible operating arm can suppress its own elastic vibration while moving to the designated position.

Further, said step four includes:

a. Based on the input shaping method, the modal vibration shaping controller for the first two modes of the flexible manipulator is constructed, and the relationship between the modal vibration shaping controller and the modal frequency of the flexible manipulator is determined.

b. Based on the cascade method, the modal vibration shaping controller of the first two modes of the flexible manipulator is integrated to form an elastic vibration active disturbance rejection controller of the flexible manipulator.

c. The reference displacement signal of the positioning base is convolved with the elastic vibration active disturbance rejection controller to obtain the displacement control signal of the positioning base.

The beneficial effects of the present invention are:

1. Taking into account the advantages of the simple structure of the feedforward controller, there is no need to set up an additional active control device for elastic vibration, which reduces the cost of the whole machine.

2. Considering the impact of the terminal load mass and boundary effects on the characteristic parameters of the robot joint vibration, the anti-interference performance of the conventional feedforward controller in the operation process of the flexible manipulator is effectively improved, and its applicability is improved.

3. The present invention has the advantages of simple control structure and high robustness.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic diagram of the principle of the present invention;

Fig. 2 is a schematic diagram of an embodiment of the present invention;

Fig. 3 is the structural representation of bolt connection system in the present invention;

Fig. 4 is when the terminal load quality is 0.1kg, the displacement curve diagram of positioning base in the present invention;

Fig. 5 is an effect diagram of elastic vibration control at the end of the flexible operating arm in the present invention when the end load mass is 0.1 kg.

Description of reference signs: 1—bolt connection system, 2—positioning base, 3—flexible operating arm, 4—end load, 5—signal acquisition device I, 6—image acquisition device, 7—signal acquisition device II, 8— Signal processing module II, 9—signal processing module I, 10—frequency calculation module, 11—elastic vibration active disturbance rejection controller, 12—motion control card, 13—motor driver, 14—servo motor, 15—coupling, 16—moving guide rail, 17—ball screw pair; 1-1—nut, 1-2—gasket I, 1-3—pressure sensor, 1-4—gasket II, 1-5—bolt.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further elaborated below.

As shown in Figures 1 to 5, a flexible operating arm elastic vibration active disturbance rejection control device includes: a flexible operating arm 3 connected to a terminal load 4; an image acquisition device 6 to obtain terminal The shape of the load 4; the positioning base 2, the motor transmission device is connected to the positioning base 2; the bolt connection system 1, which connects the flexible operating arm 3 and the positioning base 2 and can sense pressure information; the motor transmission device in turn A motor driver 13 , a motion control card 12 , an elastic vibration active disturbance rejection controller 11 and a frequency calculation module 10 are connected, and the frequency calculation module 10 is connected with a signal processing module I9 and a signal processing module II8 .

It also includes a signal acquisition device I5 connected to the bolt connection system 1 and transmitting the pressure signal to the signal processing module I9, and a signal acquisition device II7 connected to the image acquisition device 6 and transmitting the signal to the signal processing module II8.

In a preferred embodiment of the present invention, in order to realize that the motor driver 13 drives the positioning base 2, the motor transmission device includes a servo motor 14, the drive shaft of the servo motor 14 is connected with a ball screw pair 17, and the ball screw A shaft coupling 15 is provided at the joint between the rod pair 17 and the servo motor 14 , and the nut of the ball screw pair 17 is connected to the positioning base 2 , and the positioning base 2 is equipped with a moving guide rail 16 .

The bolt connection system 1 includes: bolts 1-5 passing through the positioning base 2 and the flexible operating arm 3; nuts 1-1 cooperating with the bolts 1-5; The gasket II1-4 at the place; the pressure sensor 1-3 arranged between the flexible operating arm 3 and the nut 1-1; the gasket I1-2 arranged between the pressure sensor 1-3 and the nut 1-1, so The pressure sensors 1-3 are connected to the signal acquisition device I5 through wires.

Four sets of symmetrically distributed bolt connection systems 1 are provided at the joint between the root of the flexible operating arm 7 and the positioning base 2 . The rigid connection between the flexible operating arm 7 and the positioning base 2 is realized by the bolt connection system 1 .

The signal processing module II8 can output the mass of the end load 4 in real time according to the shape of the end load 4 using a preset work library.

When in use, the signal acquisition device I5 collects the output signals of the pressure sensors 1-3 and transmits them to the signal processing module I9, the signal acquisition device II7 collects the output signals of the image acquisition device 6 and transmits them to the signal processing module II8, and the signal processing module I9 communicates with the signal The processing module II8 transmits the processing results to the frequency calculation module 10, and the elastic vibration active disturbance rejection controller 11 determines the speed control signal according to the output result of the frequency calculation module 10, and uses the motion control card 12 and the motor driver 13 to drive the servo motor 14 to move. The servo motor 14 is connected with the ball screw pair 16 through the coupling 15, and then drives the positioning base 2 to move on the moving guide rail 16, thereby driving the flexible operating arm 7 rigidly connected with the positioning base 2 to move to a designated position.

A control method for elastic vibration self-disturbance rejection of a flexible manipulator, comprising the following steps:

Step 1: Establish a working library in which the shape of the typical end load 4 matches its own mass.

In the electronic packaging industrial assembly line, the components carried by the flexible manipulator 7, that is, the shape of the end load 4 is generally different, so it is possible to pre-set a work library whose shape matches the quality of the end load 4, so that the image acquisition device 6 and the signal can be used later. The acquisition device II7 obtains the shape of the end load 4, and then the signal processing module II8 outputs the mass of the end load 4 in real time.

Step 2. Use the signal acquisition device I5 to collect the output signals of the pressure sensors 1-3 in real time and transmit them to the signal processing module I9. The signal processing module I9 processes to obtain the matching pressure between the root of the flexible operating arm 7 and the positioning base 2 and transmits it to the frequency Operation module 10; at the same time, the signal acquisition device II7 collects the output signal of the image acquisition device 6 in real time and transmits it to the signal processing module II8. According to the work library established in step 1, the signal processing module II8 processes and obtains the quality of the end load 4 and transmits it to the frequency Operation module 10.

Step 3: Determine the real-time boundary conditions of the flexible operating arm 7 and obtain the frequency equation of the flexible operating arm 7 according to the matching pressure between the root of the flexible operating arm 7 and the positioning base 2 and the quality information of the terminal load 4 received by the frequency calculation module 10, The frequency calculation module 10 is used to determine the modal frequency of the flexible manipulator 7 .

In this embodiment, the specific calculation process of the frequency calculation module 10 is: considering the matching pressure between the root of the flexible operating arm 7 and the positioning base 2 and the quality of the end load 4, it can be known that the boundary conditions of the flexible operating arm 7 are: fixed end shear The force is equal to the matching pressure, and the bending moment is equal to 0; the bending moment at the free end is equal to 0, and the shear force is equal to the inertial force of the terminal load mass 6.

The vibration mode function expression of the flexible manipulator 7 is:

φ _n (x)＝α ₁ sinβx+α ₂ cosβx+α ₃ sinhβx+α ₄ coshβx (1)

Among them: φ _n (x) represents the nth order mode shape function of the lateral elastic vibration of the flexible manipulator 7; α ₁ , α ₂ , α ₃ and α ₄ are the coefficients of the mode shape function, which depend on the The boundary conditions of ; β is a constant also depends on the boundary conditions of the flexible manipulator 7 .

Then, substituting the boundary conditions of the flexible manipulator 7 into formula (1), and according to the existence condition of the mode shape function of the flexible manipulator 7, the frequency equation and mode shape function of the flexible manipulator 7 can be obtained as:

Among them: A and ρ respectively represent the cross-sectional area and density of the flexible manipulator 7, E, I and L represent the elastic modulus, cross-sectional moment of inertia and length of the flexible manipulator 7 respectively; x represents the spatial scale; m _t represents the terminal The mass of the load 4; P represents the matching pressure between the root of the flexible operating arm 7 and the positioning base 2.

The formula for calculating the modal frequency of the flexible manipulator 7 is:

To sum up, according to formula (2) and formula (4), the modal frequency of the flexible manipulator 7 considering the boundary effect can be obtained.

Step 4: designing the elastic vibration active disturbance rejection controller 11 and determining the displacement control signal of the positioning base 2 . Specific steps are as follows:

a. Based on the input shaping method, construct the modal vibration shaping controller of the first two modes of the flexible manipulator 7, and determine the relationship between the modal vibration shaping controller and the modal frequency of the flexible manipulator 7;

According to the existing relevant research, it is known that the first two low-order modes play a leading role in the elastic vibration of the flexible manipulator 7. Therefore, in the design process of the elastic vibration active disturbance rejection controller 11, the first two modes The first-order mode can meet the control requirements.

First, the modal vibration shaping controller for the first-order mode of the flexible manipulator 7 is designed. In order to ensure that the response of the first-order mode of the flexible manipulator 7 is equal to 0, based on the input shaping method, it can be known that:

Wherein: i represents the number of pulses of the modal vibration shaping controller of the first-order mode of the flexible manipulator 7, and 2 pulses are taken in this embodiment; respectively represent the amplitude and time delay of the i-th pulse; w ₁ and ξ ₁ represent the natural frequency and damping ratio of the first-order mode of the flexible manipulator 7, respectively.

Then, the quadratic objective function is designed according to the positioning error of the end of the flexible manipulator. Based on the optimal theory, the amplitude and time delay of the two pulses of the modal vibration shaping controller of the first-order mode of the flexible manipulator 7 are respectively:

where t represents the time scale.

Similarly, the amplitude and time delay of the two pulses of the modal vibration shaping controller of the second-order mode of the flexible manipulator 7 can be obtained as:

Wherein, w ₂ and ξ ₂ represent the natural frequency and damping ratio of the second-order mode of the flexible manipulator 7 respectively.

b. Based on the cascade method, the modal vibration shaping controller of the first two modes of the flexible manipulator 7 is integrated to form the elastic vibration active disturbance rejection controller 11 of the flexible manipulator 7;

According to the cascade method, the modal vibration shaping controller of the first-order mode of the flexible manipulator 7 and the modal vibration shaping controller of the second-order mode can be cascaded to form the elastic vibration self-resistance of the flexible manipulator 7 The calculation formula of disturbing controller 11, this calculation formula is:

c. Convolving the reference displacement signal of the positioning base 2 with the elastic vibration active disturbance rejection controller 11 to obtain a displacement control signal of the positioning base 2 .

Step 5, using the motion control card 12 and the motor driver 13 to drive the positioning base 2 to move, so that the flexible operating arm 7 can suppress its own elastic vibration while moving to a designated position.

As shown in FIG. 4 , it is a displacement curve of the front and rear positioning base 2 using the elastic vibration active disturbance rejection controller 11 of the flexible operating arm 7 when the mass of the end load 4 is equal to 0.1 kg. Wherein, the dotted line is the displacement curve of the positioning base 2 before control, and the solid line is the displacement curve of the positioning base 2 after using the elastic vibration self-disturbance rejection controller 11 . It can be seen that the movement displacement of the positioning base 2 is equal before and after using the elastic vibration ADRC controller 11 , which illustrates the correctness of the elastic vibration ADRR controller 11 .

As shown in FIG. 5 , it is an effect diagram of vibration control at the end of the front and rear flexible manipulator 7 using the elastic vibration active disturbance rejection controller 11 when the mass of the end load 4 is equal to 0.1 kg. Among them, the dotted line is the vibration displacement of the end of the flexible operating arm 7 before controlling, and the solid line is the vibration displacement of the end of the flexible operating arm 7 after using the elastic vibration self-disturbance rejection controller 11 . It can be seen that the elastic vibration active disturbance rejection controller 11 designed in this patent can effectively suppress the elastic vibration of the flexible operating arm 7 .

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and what are described in the above-mentioned embodiments and description are only the principle of the present invention, and without departing from the spirit and scope of the present invention, the present invention will also have various Variations and improvements all fall within the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. A flexible operating arm elastic vibration active disturbance rejection control device, characterized in that: comprising: a flexible operating arm (3), with an end load (4) connected to the flexible operating arm (3); An image acquisition device (6), to obtain the shape of the end load (4); A positioning base (2), the positioning base (2) is connected with a motor drive; A bolt connection system (1), which connects the flexible operating arm (3) and the positioning base (2) and can sense pressure information; The motor transmission device is sequentially connected with a motor driver (13), a motion control card (12), an elastic vibration active disturbance rejection controller (11) and a frequency operation module (10), and the frequency operation module (10) is connected with a signal Processing module I (9) and signal processing module II (8); It also includes a signal acquisition device I (5) connected to the bolt connection system (1) and transmitting the pressure signal to the signal processing module I (9), connected to the image acquisition device (6) and transmitting the signal to the signal processing module II ( 8) The signal acquisition device II (7). 2. A flexible operating arm elastic vibration active disturbance rejection control device according to claim 1, characterized in that: the bolt connection system (1) comprises: The bolts (1-5) passing through the positioning base (2) and the flexible operating arm (3); A nut (1-1) cooperating with the bolt (1-5); Gasket II (1-4) arranged at the joint between the bolt (1-5) and the positioning base (2); A pressure sensor (1-3) arranged between the flexible operating arm (3) and the nut (1-1); Set the gasket I (1-2) between the pressure sensor (1-3) and the nut (1-1). 3. The elastic vibration active disturbance rejection control device of a flexible manipulator according to claim 1, characterized in that: the signal processing module II (8) can use a preset The work library outputs the mass of the end load (4) in real time. 4. A control method for elastic vibration self-disturbance rejection of a flexible manipulator, characterized in that: comprising the following steps: Step 1, establishing a working library in which the shape of a typical end load (4) matches its own mass; Step 2: Use the signal acquisition device I (5) to collect the output signal of the pressure sensor (1-3) in real time and transmit it to the signal processing module I (9), and the signal processing module I (9) processes to obtain the flexible operating arm (7) The matching pressure between the root and the positioning base (2) is transmitted to the frequency calculation module (10); at the same time, the signal acquisition device II (7) collects the output signal of the image acquisition device (6) in real time and transmits it to the signal processing module II (8) , according to the work library established in step 1, the signal processing module II (8) processes and obtains the quality of the end load (4) and transmits it to the frequency operation module (10); Step 3: Determine the real-time boundary conditions of the flexible manipulator (7) according to the matching pressure between the root of the flexible manipulator (7) and the positioning base (2) and the mass information of the terminal load (4) received by the frequency calculation module (10) , obtain the frequency equation of the flexible manipulator (7), and use the frequency operation module (10) to determine the modal frequency of the flexible manipulator (7); Step 4, designing the elastic vibration active disturbance rejection controller (11), and determining the displacement control signal of the positioning base (2); Step 5, using the motion control card (12) and the motor driver (13) to drive the positioning base (2) to move, so that the flexible operating arm (7) can suppress its own elastic vibration while moving to a designated position. 5. A control method for elastic vibration self-disturbance rejection of a flexible manipulator according to claim 4, characterized in that: said step 4 comprises: a. Based on the input shaping method, construct the modal vibration shaping controller of the first two modes of the flexible manipulator (7), and determine the relationship between the modal vibration shaping controller and the modal frequency of the flexible manipulator (7); b. Based on the cascade method, the modal vibration shaping controller of the first two modes of the flexible manipulator (7) is integrated to form the elastic vibration active disturbance rejection controller (11) of the flexible manipulator (7); c. Convolving the reference displacement signal of the positioning base (2) with the elastic vibration active disturbance rejection controller (11) to obtain a displacement control signal of the positioning base (2).