Swing type low-frequency active dynamic vibration absorption device and control system and method thereof

Abstract

The invention relates to the technical field of mechanical arm control, in particular to a swing type low-frequency active dynamic vibration absorption device and a control system and method thereof. Comprising a swing arm mechanism, a rotating mechanism and a rotating disc, the swing arm mechanism comprises a pendulum bob, a swing rod, a swing arm motor and a motor support, the swing arm mechanism comprises a first swing arm mechanism and a second swing arm mechanism which are symmetrically arranged at the upper end of the rotating disc, and the swing arm motor is located at the upper end of the motor support and fixedly connected with the motor support; the rotating disc is located at the lower end of the motor support and fixedly connected with the motor support, the pendulum bob is in flange connection with the swing rod, the swing rod is connected with a motor shaft of the swing arm motor, and the swing arm mechanism further comprises a supporting device used for providing supporting force for the motor shaft. The rotating mechanism comprises a rotating motor, a rigid supporting structure and a chassis, a motor shaft of the rotating motor is fixedly connected with the rotating disc, and the rigid supporting structure is connected with the rotating disc and the chassis.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical arm control, and in particular to a swing-type low-frequency active dynamic vibration absorbing device and a control system and method thereof. Background Art

[0002] Space manipulators usually adopt the design of slender rods, and the joints are equipped with harmonic reducers and joint Liju sensors. The introduction of these flexible structures makes the space manipulator face a key problem. During the movement of the manipulator or when it is disturbed by external disturbances, the flexible structure may cause the manipulator itself to vibrate. According to the flexibility of the space manipulator, it can be divided into three types: flexible joint-rigid link manipulator, rigid joint-flexible link manipulator, and flexible joint-flexible link manipulator. At present, for the pre-research space manipulator, after the joint motion control algorithm is used for vibration suppression, low-frequency vibration still exists, which seriously affects the control accuracy and fine operation of the manipulator. Vibration suppression for the manipulator mainly consists of two solutions: joint motion control and dynamic vibration absorber. Joint motion control cannot play a role in suppressing the low-frequency residual vibration of the manipulator, and the dynamic vibration absorber generally adopts a linear dynamic vibration absorber solution. However, for the low-frequency vibration of the space manipulator, the traditional linear motion dynamic vibration absorber solution will have a long stroke problem. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a swing-type low-frequency active dynamic vibration absorption device and a control system and method thereof, which can reduce the impact of low-frequency vibration at the end of a mechanical arm.

[0004] The basic scheme provided by the present invention is: a swing-type low-frequency active dynamic vibration absorbing device and its control system, comprising a swing arm mechanism, a rotating mechanism and a rotating disk, the swing arm mechanism comprising a pendulum, a swing rod, a swing arm motor, and a motor bracket, the swing arm mechanism comprising a first swing arm mechanism and a second swing arm mechanism, which are symmetrically arranged at the upper end of the rotating disk, the swing arm motor is located at the upper end of the motor bracket and is fixedly connected to the motor bracket, the rotating disk is located at the lower end of the motor bracket and is fixedly connected to the motor bracket, the pendulum is connected to the swing rod flange, the swing rod is connected to the motor shaft of the swing arm motor, and the swing arm mechanism also includes a supporting device, which is used to provide a supporting force for the motor shaft; The rotating mechanism comprises a rotating motor, a rigid supporting structure and a chassis, wherein the motor shaft of the rotating motor is fixedly connected to the rotating disk, the rigid supporting structure connects the rotating disk and the chassis, and the rotating mechanism is used to rotate following the vibration direction of the end of the flexible arm; It also includes a control module, which includes a controller and a gyroscope. The controller is point-connected to the gyroscope, and the controller is electrically connected to the swing arm motor and the rotating motor. The gyroscope is used to obtain the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction and send them to the controller. The controller calculates the rotation speed of the swing arm mechanism according to the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction, and controls the swing arm motor to operate at the rotation speed.

[0005] Furthermore, the supporting device includes a bearing bracket, a connecting plate, a sleeve, a deep groove ball bearing and a bearing lower bracket. The motor shaft of the swing arm motor is provided with a sleeve. The deep groove ball bearing is arranged on the bearing bracket and cooperates with the sleeve. The lower end of the bearing lower bracket is fixedly connected to the rotating disk, and the upper end is connected to the bearing bracket through a connecting plate.

[0006] Furthermore, the rigid support structure includes a fixing frame, a bearing frame, and an angular contact bearing. The sleeve cooperates with the motor shaft of the rotating motor, the bearing frame cooperates with the sleeve, the upper end of the fixing frame is fixedly connected to the lower end of the bearing frame, and the lower end of the fixing frame is fixedly connected to the chassis.

[0007] Furthermore, the pendulum is provided with a pendulum cover, the plate hammer cover is processed with an annular groove, and a detachable rubber sealing strip is provided in the annular groove.

[0008] Furthermore, it also includes a top plate, which is located above the swing arm mechanism, and an electric slider is provided below the top plate. The rotating shaft of the electric slider is fixedly connected to the rotating plate, and the controller is electrically connected to the swing arm motor and the rotating motor through the electric slider.

[0009] The principle and advantage of the present invention lies in that the swing ball type dynamic vibration absorber includes a rotating mechanism, a swing arm mechanism and other auxiliary structures in structure, and includes a control system of an embedded operating system in software.

[0010] The swing arm mechanism is mainly responsible for generating force to suppress the vibration of the end of the robot arm, and the rotating mechanism is mainly responsible for adjusting the direction of the force generated by the swing arm mechanism so that the force direction of the swing arm mechanism is always the same as the vibration direction of the end of the robot arm. The auxiliary mechanism mainly includes components such as electric slip rings, which ensure that the rotating mechanism can rotate 360° freely. The control system program mainly includes a cosine modulation anti-disturbance control algorithm designed based on a linear anti-disturbance algorithm, which makes the designed swing ball dynamic vibration absorber have a good working effect.

[0011] The tracking-differentiator is moved from the input to the output. On the one hand, this is a vibration suppression algorithm, the expected signal is 0, and a tracking-differentiator is not needed; on the other hand, there is a step value in the modulated cosine output, and the tracking-differentiator can smoothly handle this sudden change.

[0012] Traditional nonlinear ADRC requires adjustment of 12 parameters, and linear ADRC requires adjustment of 6 parameters. After pole configuration, linear ADRC only requires adjustment of 3 parameters, allowing it to be quickly deployed in engineering applications.

[0013] In order to reduce the impact of the motor, a speed output modulation method is proposed. After simulation and experimental verification, this method can greatly reduce the impact of the motor and provide a basis for vibration suppression.

[0014] The controller inherits the model-independence characteristics of the traditional classic ADRC, so that the dynamic vibration absorber can suppress the vibration of the flexible arm without relying on the mathematical model. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a swing arm mechanism in an embodiment of a swing-type low-frequency active dynamic vibration absorbing device and a control system thereof of the present invention; Figure 2 It is a structural schematic diagram of a rotating mechanism in an embodiment of a swing-type low-frequency active dynamic vibration absorbing device and a control system thereof of the present invention; Figure 3 It is a structural schematic diagram of an embodiment of a swing-type low-frequency active dynamic vibration absorbing device and a control system thereof of the present invention; Figure 4 The control block diagram of the traditional active disturbance rejection controller controlling the swing type dynamic vibration absorber; Figure 5 This is a control block diagram of a swing-type low-frequency active dynamic vibration absorber and a control system thereof in an embodiment of the present invention, using a cosine modulation anti-disturbance controller to control a swing dynamic vibration absorber; Figure 6 It is a circuit connection diagram of a swing ball type dynamic vibration absorber in an embodiment of a swing type low frequency active dynamic vibration absorption device and a control system thereof of the present invention; Figure 7 It is a logic block diagram between various peripherals and the main control board of a swing ball type dynamic vibration absorber in an embodiment of a swing type low frequency active dynamic vibration absorption device and a control system thereof of the present invention; Figure 8 The present invention is a schematic diagram showing the principle of vibration suppression achieved by a swing arm mechanism in an embodiment of a swing-type low-frequency active dynamic vibration absorbing device and a control system thereof. DETAILED DESCRIPTION

[0016] The following is further described in detail through specific implementation methods: The marks in the drawings of the specification include: pendulum 1, pendulum cover 2, pendulum connecting flange 3, bearing bracket 4, connecting plate 5, bushing 6, deep groove ball bearing 7, rocker arm connecting flange 8, rocker arm 9, rocker arm motor 10, motor bracket 11, bearing lower bracket 12, rotating disk 13, motor shaft 14, bushing 15, motor shaft 16, angular contact bearing 17, bearing end cover 18, bearing bracket 19, fixing frame 20, chassis 21, motor bracket 22, rotating motor 23, bushing 24, electric slip ring 25, electric slip ring rotating shaft 26, support frame 27, top plate 28.

[0017] The embodiment is basically as shown in the attached Figure 1 As shown: A swing-type low-frequency active dynamic vibration absorbing device and its control system, including a swing arm mechanism, a rotating mechanism and a rotating disk 13, the swing arm mechanism including a pendulum 1, a pendulum rod 8, a swing arm motor 10, and a motor bracket 11, the pendulum cover 2 is processed with an annular groove, and a rubber sealing strip can be embedded in the groove, so that the inside of the pendulum 1 can not only accommodate solid substances, but also allow liquid injection to increase the damping effect. However, substances can only be added statically, and substances cannot be changed during operation. The pendulum 1 and the pendulum cover 2 are connected to the pendulum rod 9 through the top screw threaded hole of the pendulum connecting flange 3, and the pendulum rod connecting flange 8 and the pendulum rod 9 are also fixedly connected through the top screw threaded hole. Pre-tightening force is provided by the bolt and nut connection at the rear end to clamp the motor shaft 14. In order to prevent the centrifugal force of the pendulum from directly applying an overturning torque to the motor shaft 14, thereby avoiding damage to the brushless motor 10, a set of support devices consisting of a bearing bracket 4, a connecting plate 5, a sleeve 6, a deep groove ball bearing 7 and a bearing lower bracket 12 are designed. These components provide support force for the motor shaft 14. The brushless motor 10, the motor bracket 11 and the rotating disk 13 are firmly connected by screws. In order to avoid force disturbance caused by uneven mass distribution, the brushless motor 10 and its related pendulum accessories are designed to be symmetrically distributed. In terms of material selection, the pendulum rod 9 and the motor shaft 14 are made of 45 steel because they have to withstand certain bending and torsional strengths; the connecting piece 5 is fixed to the two brackets and also requires a certain bending strength, so Q235 carbon structural steel is selected; other parts are made of aluminum alloy 6063 for weight reduction considerations.

[0018] like Figure 2 As shown, the rotating mechanism includes a rotating motor 23, a rigid support structure and a chassis 21. The motor shaft 16 of the rotating motor 23 is fixedly connected to the rotating disk 13. The rigid support structure connects the rotating disk 13 and the chassis 21. The rotating mechanism is used to rotate following the vibration direction of the end of the flexible arm.

[0019] The rotating disk 13 is fixedly connected to the motor shaft 14 by screws. The shaft sleeve 15, the shaft sleeve 24, a pair of angular contact bearings 17, the bearing end cover 18, the bearing bracket 19 and the fixing frame 20 form a set of rigid support structures, which transmit the force exerted on the rotating disk 13 to the chassis 21, avoiding direct application on the motor shaft 14 and the rotating motor 23, ensuring that the rotating disk 13 can run smoothly, while minimizing the additional load on the brushless motor, thereby optimizing the overall system performance. The rotating motor 13 provides the required rotational torque for the rotating disk 13.

[0020] In terms of material selection, the motor shaft 14 and the sleeve 24 are made of 45 steel, while other parts are made of aluminum alloy 6063 to ensure the structural strength and lightweight design.

[0021] like Figure 3 As shown, the diameters of the chassis 21 and the top plate 28 are determined according to the outer diameter of 200 mm at the end of the three-degree-of-freedom flexible manipulator. The chassis 21 can be installed at the end of the manipulator, while the top plate 28 can be used to install the end actuator of the manipulator, such as a mechanical gripper, an actuator cylinder, etc. In order to ensure that the rotating disk can achieve 360° unlimited rotation, an electric slip ring 25 is installed under the top plate 228. The existence of the electric slip ring 25 makes the rotating mechanism 26 not restricted by the swing arm mechanism A in terms of circuit wiring, so that the rotating mechanism B can rotate to the target position in the shortest path. The electric slip ring rotating shaft 26 is installed on the rotating disk of the rotating mechanism B, driving the electric slip ring 25 to rotate at the same speed as the rotating disk. The material of the support frame 27 is Q235 carbon structural steel, while other components are made of aluminum alloy 6063 to ensure the firmness and lightweight design of the system. The rotating structure B can rotate 360° following the vibration direction of the end of the flexible arm. The motor of the swing arm mechanism A can swing according to the speed calculated by the cosine modulation anti-disturbance controller. It can only swing within a range of 180° and cannot rotate a full circle.

[0022] The invention also includes a control module, which includes a controller and a gyroscope. The controller is point-connected to the gyroscope, and the controller is electrically connected to the swing arm motor and the rotating motor. The gyroscope is used to obtain the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction and send them to the controller. The controller calculates the rotation speed of the swing arm mechanism according to the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction through a preset cosine modulation anti-disturbance control algorithm, and controls the swing arm motor to operate at the rotation speed.

[0023] The control block diagram of the traditional active disturbance rejection controller controlling the swing dynamic vibration absorber is as follows: Figure 4 shown.

[0024] The control block diagram of the cosine modulation active disturbance rejection controller used in this application to control the swing dynamic vibration absorber is as follows: Figure 5The cosine modulation ADRC has five parameters, which are the estimated values ​​of the system mechanism driving characteristic coefficients, ; Bandwidth of error feedback control rate ; Extended state observer bandwidth ;TD tracking speed factor ;TD filter factor .

[0025] Compared with the traditional classic ADRC, this controller has the following characteristics: 1. The tracking-differentiator is moved from the input end to the output end. On the one hand, this is because this is a vibration suppression algorithm, the expected signal is 0, and the tracking-differentiator is not needed; on the other hand, the modulated cosine output has a step value, and the tracking-differentiator can smoothly handle this sudden change value.

[0026] 2. Traditional nonlinear ADRC requires adjustment of 12 parameters, linear ADRC requires adjustment of 6 parameters, and linear ADRC after pole configuration only requires adjustment of 3 parameters, so that it can be quickly deployed in engineering applications.

[0027] 3. In order to reduce the impact of the motor, a speed output modulation method is proposed. After simulation and experimental verification, this method can greatly reduce the impact of the motor and provide a basis for vibration suppression.

[0028] 4. This controller inherits the model-independence characteristics of the traditional classic ADRC, so that the dynamic vibration absorber can suppress the vibration of the flexible arm without relying on the mathematical model.

[0029] The circuit connection diagram of the swing ball dynamic vibration absorber is as follows Figure 6 As shown, the main power supply of the dynamic vibration absorber is 24V and 5V. In order to allow the electrical components on the swing arm mechanism to rotate freely without being restricted by the wiring, the wiring on the swing arm mechanism must pass through the electric slip ring. At the same time, the speed and power of the swing arm motor determine the output frequency of the output force. The torque of the selected brushless swing arm motor is 5Nm and the speed is 505rpm. After calculation, it can be known that the maximum swing frequency can reach 9Hz, so the dynamic vibration absorber can be used for low-frequency vibrations below 9Hz.

[0030] The communication method between the various peripherals of the swing ball dynamic vibration absorber and the main control board is as follows Figure 7As shown. It mainly consists of CAN protocol, serial communication and external interrupt. The six-axis electronic gyroscope module can measure the acceleration value of the end of the flexible arm in the X direction and Y direction in real time, and the value is sent to the STM32F103 industrial control board through the serial port. The industrial control board calculates the rotation angle of the rotating mechanism according to the acceleration values ​​in the X direction and Y direction, and uses the acceleration values ​​in the X direction and Y direction as the input of the cosine anti-disturbance algorithm for calculation. The value calculated by the cosine modulation anti-disturbance algorithm is the rotation speed of the swing arm mechanism motor. The calculated rotation angle and rotation speed are transmitted to the corresponding motor through the CAN interface respectively. After the rotating motor receives the rotation angle information, it rotates to the corresponding angle. After the two swing arm motors receive the rotation speed information, they swing synchronously according to the received information.

[0031] The principle diagram of the swing arm mechanism to achieve vibration suppression is as follows Figure 8 shown.

[0032] At this time, the resultant force along the X direction is shown in the following formula: (1) The resultant force along the Y direction is given by the following formula: (2) When the pendulum length L1=L2=L, m1=m2=m, and the deflection angle θ of the pendulum ball and the Y axis is the same, the final resultant force along the X direction is shown in the following formula: (3) The magnitude of the resultant force along the Y direction is given by the following formula: (4) In the formula, is the initial position of the ball's swing.

[0033] By analyzing equations (3) and (4), we can know that the resultant force of the two pendulum balls in the X direction is 0, while the magnitude of the resultant force in the Y direction is positively correlated with the angular velocity ω. In addition, as the ball continues to swing, the direction of the resultant force in the Y direction will also move on the positive and negative axes. When the swing frequency of the two balls is consistent with the vibration frequency of the flexible arm, and the swing direction of the balls is opposite to the vibration direction of the flexible arm, the condition of applying opposite forces to the vibration direction of the flexible arm is achieved. In this case, the vibration can be effectively suppressed, achieving the goal of suppressing the vibration of the flexible arm.

[0034] The above are only embodiments of the present invention. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A swing-type low-frequency active dynamic vibration absorbing device and its control system, characterized in that: It includes a swing arm mechanism, a rotating mechanism and a rotating disk, the swing arm mechanism includes a pendulum, a swing rod, a swing arm motor, and a motor bracket, the swing arm mechanism includes a first swing arm mechanism and a second swing arm mechanism, which are symmetrically arranged on the upper end of the rotating disk, the swing arm motor is located at the upper end of the motor bracket and is fixedly connected to the motor bracket, the rotating disk is located at the lower end of the motor bracket and is fixedly connected to the motor bracket, the pendulum is connected to the swing rod flange, the swing rod is connected to the motor shaft of the swing arm motor, and the swing arm mechanism also includes a supporting device, which is used to provide a supporting force for the motor shaft; The rotating mechanism comprises a rotating motor, a rigid supporting structure and a chassis, wherein the motor shaft of the rotating motor is fixedly connected to the rotating disk, the rigid supporting structure connects the rotating disk and the chassis, and the rotating mechanism is used to rotate following the vibration direction of the end of the flexible arm; The invention also includes a control module, which includes a controller and a gyroscope. The controller is point-connected to the gyroscope, and the controller is electrically connected to the swing arm motor and the rotating motor. The gyroscope is used to obtain the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction and send them to the controller. The controller calculates the rotation speed of the swing arm mechanism according to the acceleration values ​​of the end of the flexible arm in the X direction and the Y direction through a preset cosine modulation anti-disturbance control algorithm, and controls the swing arm motor to operate at the rotation speed.

2. The swing-type low-frequency active dynamic vibration absorbing device and its control system according to claim 1, characterized in that: The supporting device includes a bearing bracket, a connecting plate, a sleeve, a deep groove ball bearing and a bearing lower bracket. The motor shaft of the swing arm motor is provided with a sleeve. The deep groove ball bearing is arranged on the bearing bracket and cooperates with the sleeve. The lower end of the bearing lower bracket is fixedly connected to the rotating disk, and the upper end is connected to the bearing bracket through a connecting plate.

3. The swing-type low-frequency active dynamic vibration absorbing device and its control system according to claim 1, characterized in that: The rigid support structure includes a fixing frame, a bearing frame, and an angular contact bearing. The sleeve cooperates with the motor shaft of the rotating motor, the bearing frame cooperates with the sleeve, the upper end of the fixing frame is fixedly connected to the lower end of the bearing frame, and the lower end of the fixing frame is fixedly connected to the chassis.

4. The swing-type low-frequency active dynamic vibration absorbing device and its control system according to claim 1, characterized in that: The pendulum is also provided with a pendulum cover, the plate hammer cover is processed with an annular groove, and a detachable rubber sealing strip is arranged in the annular groove.

5. The swing-type low-frequency active dynamic vibration absorbing device and its control system according to claim 1, characterized in that: It also includes a top plate, which is located above the swing arm mechanism. An electric slider is arranged below the top plate. The rotating shaft of the electric slider is fixedly connected to the rotating plate. The controller is electrically connected to the swing arm motor and the rotating motor through the electric slider.

6. A swing-type low-frequency active dynamic vibration absorbing device and a control method thereof, characterized in that: A swing-type low-frequency active dynamic vibration absorbing device and a control system thereof as described in any one of claims 1 to 5 are used.

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