阅读说明：本技术 基于分布扰动的柔性杆振动抑制方法及系统 (Flexible rod vibration suppression method and system based on distributed disturbance ) 是由 马艺飞 楼旭阳 吴炜 于 2020-12-31 设计创作，主要内容包括：本发明涉及柔性杆的振动抑制技术领域,具体公开了一种基于分布扰动的柔性杆振动抑制方法,其中,包括：基于分布扰动力对柔性杆进行建模；采集柔性杆的边界状态信息；根据柔性杆的边界状态信息以及柔性杆模型构建边界抗饱和控制器,边界抗饱和控制器能够输出执行器控制值；根据边界抗饱和控制器的输出判断执行器控制值是否达到执行器饱和上限；若达到,则根据柔性杆的边界状态信息以及超过执行器饱和上限的部分设计辅助系统；在确定柔性杆稳定时,获得边界抗饱和控制器的增益取值范围。本发明还公开了一种基于分布扰动的柔性杆振动抑制系统。本发明提供的基于分布扰动的柔性杆振动抑制方法能够对柔性杆的弹性震动进行抑制。(The invention relates to the technical field of vibration suppression of flexible rods, and particularly discloses a flexible rod vibration suppression method based on distributed disturbance, wherein the method comprises the following steps: modeling the flexible rod based on the distributed disturbance force; collecting boundary state information of the flexible rod; constructing a boundary anti-saturation controller according to the boundary state information of the flexible rod and the flexible rod model, wherein the boundary anti-saturation controller can output an actuator control value; judging whether the control value of the actuator reaches the upper limit of the saturation of the actuator or not according to the output of the boundary anti-saturation controller; if so, designing an auxiliary system according to the boundary state information of the flexible rod and the part exceeding the saturation upper limit of the actuator; and when the stability of the flexible rod is determined, obtaining the gain value range of the boundary anti-saturation controller. The invention also discloses a flexible rod vibration suppression system based on distributed disturbance. The flexible rod vibration suppression method based on distributed disturbance provided by the invention can suppress the elastic vibration of the flexible rod.)

1. A flexible rod vibration suppression method based on distributed disturbance is characterized by comprising the following steps:

modeling the flexible rod based on the distributed disturbance force to obtain a flexible rod model;

collecting boundary state information of the flexible rod;

constructing a boundary anti-saturation controller according to the boundary state information of the flexible rod and the flexible rod model, wherein the boundary anti-saturation controller can output an actuator control value;

judging whether the control value of the actuator reaches the upper limit of the saturation of the actuator according to the output of the boundary anti-saturation controller;

if so, designing an auxiliary system according to the boundary state information of the flexible rod and the part exceeding the saturation upper limit of the actuator, wherein the auxiliary system is used for eliminating the saturation nonlinear influence of the actuator;

and obtaining the gain value range of the boundary anti-saturation controller when the stability of the flexible rod is determined.

2. The distributed perturbation based flexible rod vibration suppression method according to claim 1, wherein the modeling of the flexible rod based on the distributed perturbation force results in a flexible rod model, comprising:

and modeling the flexible rod according to a Lagrange equation and a Hamilton principle to obtain a system equation and boundary conditions of the Euler-Bernoulli beam.

3. The distributed perturbation based flexible rod vibration suppression method of claim 2,

the expression of the system equation of the Euler-Bernoulli beam is as follows:

the expression of the boundary condition is:

wherein, ω (x, t) < 0, L]X [0, + ∞) → R denotes the transverse displacement of the flexible rod in space x and time T coordinates, p, T, E_IM and L represent the mass per unit length of the beam, the tension, the bending stiffness, the mass of the tip load and the length of the beam system, respectively, omega_x(x, t) and ω_t(x, t) represents the derivative of the transverse displacement ω (x, t) of the rod with respect to space x and time t, respectively, and f (x, t) represents that the disturbance of the spatial distribution is assumed to exist with an upper bound satisfyingu (t) denotes a boundary controller; sat (u (t)) represents a saturation controller, and the expression is as follows:

wherein u is_maxAnd u_minRepresenting the upper and lower bounds of the actuator, respectively.

4. The distributed perturbation based flexible rod vibration suppression method according to claim 3, wherein the acquiring boundary state information of the flexible rod comprises:

acquiring boundary velocity omega of flexible rod_t(L, t), boundary curvature ω_x(L, t) and the speed ω of the boundary bending_xt(L,t)。

5. The distributed perturbation based flexible rod vibration suppression method of claim 4, wherein the expression of the auxiliary system is:

wherein z (t) represents the state of the auxiliary system, k_zα, β, ε each represent a constant greater than 0, sgn (z (t)) represents a sign function; Δ u (t) is a saturation dead-zone function, denoted as Δ u (t) sat (u (t)) u (t).

6. The distributed perturbation based flexible rod vibration suppression method of claim 4, wherein the expression of the boundary anti-saturation controller is:

u(t)＝-k_aω_t(L,t)+k_bω_x(L,t)-k_cω_xt(L,t)+k_dz(t)，

wherein k is_a,k_b,k_c,k_dBoth represent gains of the boundary anti-saturation controller greater than 0.

7. The distributed disturbance-based flexible rod vibration suppression method according to claim 4, wherein obtaining a gain value range of the boundary anti-saturation controller when the flexible rod is determined to be stable comprises:

selecting a Lyapunov function, wherein the expression is as follows:

V(t)＝V₁(t)+V₂(t)+V₃(t)+V₄(t)，

wherein both alpha and beta are greater than 0, V₁(t) represents an energy term consisting of kinetic and potential energy, V₂(t) denotes the cross term, V₃(t) represents an energy term, V, associated with the state of the auxiliary system₄(t) represents an auxiliary item;

verifying the positive nature of the Lyapunov function to obtain:

0<α₃(V₁(t)+V₃(t)+V₄(t))≤V(t)≤α₄(V₁(t)+V₃(t)+V₄(t))，

wherein alpha is₃＝min{(1-υ),1}，α₄＝max{(1+υ),1}，

Verifying the first derivative negative nature of the Lyapunov function to time t by combining the boundary state information and the boundary anti-saturation controller, and obtaining the gain value range of the boundary anti-saturation controller;

the state of the flexible rod is obtained by the following steps:

wherein the content of the first and second substances,and when t → ∞ is reached,

8. a distributed disturbance based flexible rod vibration suppression system, comprising:

the sensor is used for acquiring boundary state information of the flexible rod;

the boundary anti-saturation controller is used for outputting a control signal of the actuator according to the boundary state information of the flexible rod;

the auxiliary system is used for eliminating the saturated nonlinear influence of the actuator according to the boundary state information of the flexible rod;

and the actuator is used for receiving the control signal of the boundary anti-saturation controller and acting on the flexible rod.

9. The distributed perturbation based flexible rod vibration suppression system of claim 8, wherein the sensor comprises: the device comprises a laser displacement sensor, an inclinometer and a pressure strain gauge.

Technical Field

The invention relates to the technical field of vibration suppression of flexible rods, in particular to a flexible rod vibration suppression method based on distribution disturbance and a flexible rod vibration suppression system based on distribution disturbance.

Background

The flexible rod has the advantages of light weight, high precision, low energy consumption, large operation space and the like, and is widely applied to the fields of robots, spaceflight and industry, so the flexible rod has important theoretical significance and practical application value for dynamic modeling and vibration control of a flexible rod system. In the actual operation process, the flexible system has the vibration characteristic, so that elastic vibration is easily caused in the movement process, the positioning precision of the flexible rod in the movement process is reduced, and even the reliability of the system is reduced. Under the same control method, accurate positioning accuracy or a desired trajectory cannot be obtained. Therefore, it is very important to suppress the vibration problem of the flexible mechanical arm or the flexible system during the movement.

In the actual industrial process, the boundary control is a more practical and easier control mode, and the vibration suppression of the whole flexible rod is realized by adjusting the magnitude of the boundary control force. Due to the limitation of the physical conditions of the actuator, the output torque of the actuator is limited and cannot be output according to the ideal torque. In addition, due to various complex disturbances such as wind disturbance and air resistance in the practical application environment, under various complex conditions, the vibration suppression of the flexible rod may be affected, an ideal vibration suppression effect cannot be achieved to destroy the stability of the flexible rod, and even the flexible rod is in elastic deformation for a long time to destroy the structure of the flexible rod, so that the actual industrial operation process is affected.

Disclosure of Invention

The invention provides a flexible rod vibration suppression method based on distributed disturbance and a flexible rod vibration suppression system based on distributed disturbance, and solves the problem that elastic vibration of a flexible rod cannot be suppressed in the related art.

As a first aspect of the present invention, there is provided a flexible rod vibration suppression method based on distributed disturbance, including:

modeling the flexible rod based on the distributed disturbance force to obtain a flexible rod model;

collecting boundary state information of the flexible rod;

constructing a boundary anti-saturation controller according to the boundary state information of the flexible rod and the flexible rod model, wherein the boundary anti-saturation controller can output an actuator control value;

judging whether the control value of the actuator reaches the upper limit of the saturation of the actuator according to the output of the boundary anti-saturation controller;

if so, designing an auxiliary system according to the boundary state information of the flexible rod and the part exceeding the saturation upper limit of the actuator, wherein the auxiliary system is used for eliminating the saturation nonlinear influence of the actuator;

and obtaining the gain value range of the boundary anti-saturation controller when the stability of the flexible rod is determined.

Further, the modeling the flexible rod based on the distributed disturbance force to obtain a flexible rod model includes:

and modeling the flexible rod according to a Lagrange equation and a Hamilton principle to obtain a system equation and boundary conditions of the Euler-Bernoulli beam.

Further, the expression of the system equation of the Euler-Bernoulli beam is as follows:

the expression of the boundary condition is:

wherein, ω (x, t) < 0, L]X [0, + ∞) → R denotes the transverse displacement of the flexible rod in space x and time T coordinates, p, T, E_IM and L represent the mass per unit length of the beam, the tension, the bending stiffness, the mass of the tip load and the length of the beam system, respectively, omega_x(x, t) and ω_t(x, t) represents the derivative of the transverse displacement ω (x, t) of the rod with respect to space x and time t, respectively, and f (x, t) represents that the spatial distribution disturbance is assumed to have an upper bound satisfyingu (t) denotes a boundary controller; sat (u (t)) represents a saturation controller, and the expression is as follows:

wherein u is_maxAnd u_minRepresenting the upper and lower bounds of the actuator, respectively.

Further, the collecting boundary state information of the flexible rod comprises:

acquiring boundary velocity omega of flexible rod_t(L, t), boundary curvature ω_x(L, t) and the speed ω of the boundary bending_xt(L,t)。

Further, the expression of the auxiliary system is as follows:

wherein z (t) represents the state of the auxiliary system, k_zα, β, and ∈ each denote a constant greater than 0, sgn (z (t)) denotes a sign function; Δ u (t) is a saturation dead-zone function, denoted as Δ u (t) sat (u (t)) u (t).

Further, the expression of the boundary anti-saturation controller is as follows:

u(t)＝-k_aω_t(L,t)+k_bω_x(L,t)-k_cω_xt(L,t)+k_dz(t)，

wherein k is_a,k_b,k_c,k_dBoth represent gains of the boundary anti-saturation controller greater than 0.

Further, when it is determined that the flexible rod is stable, obtaining a gain value range of the boundary anti-saturation controller includes:

selecting a Lyapunov function, wherein the expression is as follows:

V(t)＝V₁(t)+V₂(t)+V₃(t)+V₄(t)，

wherein both alpha and beta are greater than 0, V₁(t) represents an energy term consisting of kinetic and potential energy, V₂(t) denotes the cross term, V₃(t) represents an energy term, V, associated with the state of the auxiliary system₄(t) represents an auxiliary item;

verifying the positive nature of the Lyapunov function to obtain:

0<α₃(V₁(t)+V₃(t)+V₄(t))≤V(t)≤α₄(V₁(t)+V₃(t)+V₄(t))，

wherein alpha is₃＝min{(1-υ),1}，α₄＝max{(1+υ),1}，

Verifying the first derivative negative nature of the Lyapunov function to time t by combining the boundary state information and the boundary anti-saturation controller, and obtaining the gain value range of the boundary anti-saturation controller;

the state of the flexible rod is obtained by the following steps:

wherein the content of the first and second substances,and when t → ∞ is reached,

as another aspect of the present invention, there is provided a distributed disturbance based flexible rod vibration suppression system, comprising:

the sensor is used for acquiring boundary state information of the flexible rod;

the boundary anti-saturation controller is used for outputting a control signal of the actuator according to the boundary state information of the flexible rod;

the auxiliary system is used for eliminating the saturated nonlinear influence of the actuator according to the boundary state information of the flexible rod;

and the actuator is used for receiving the control signal of the boundary anti-saturation controller and acting on the flexible rod.

Further, the sensor includes: the device comprises a laser displacement sensor, an inclinometer and a pressure strain gauge.

According to the flexible rod vibration suppression method based on distribution disturbance, the boundary anti-saturation controller is adopted to eliminate the influence of actuator saturation limitation and unknown distribution disturbance on the stability of the flexible rod, loss caused by the fact that the flexible rod is in elastic vibration for a long time is prevented, and the flexible rod obtains higher precision in practical engineering application. In addition, the method for suppressing the vibration of the flexible rod based on the distributed disturbance, provided by the embodiment of the invention, considers the influence of the distributed disturbance force, and can overcome the problems that the flexible machine is limited by actuator saturation in the industrial process, the external unknown distributed disturbance and the like, the stability of the flexible rod is damaged, and the influence of long-time elastic vibration is caused.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a flow chart of a distributed disturbance-based method for suppressing vibration of a flexible rod according to the present invention.

Fig. 2 is a schematic view of a flexible rod structure provided by the present invention.

FIG. 3 is a flow chart of boundary anti-saturation control provided by the present invention.

FIG. 4 is a graph of the vibration displacement of a flexible rod using a boundary anti-saturation controller under distributed disturbance according to the present invention.

FIG. 5 is a graph of the flexible rod boundary vibration displacement with the boundary anti-saturation controller under distributed disturbance according to the present invention.

FIG. 6 is a block diagram of a distributed disturbance based vibration suppression system for a flexible rod according to the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances in order to facilitate the description of the embodiments of the invention herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the present embodiment, a distributed disturbance-based flexible rod vibration suppression method is provided, and fig. 1 is a flowchart of a distributed disturbance-based flexible rod vibration suppression method according to an embodiment of the present invention, as shown in fig. 1, including:

s110, modeling the flexible rod based on distributed disturbance force to obtain a flexible rod model, wherein the flexible rod model is a structural schematic diagram of the flexible rod as shown in FIG. 2;

s120, collecting boundary state information of the flexible rod;

s130, constructing a boundary anti-saturation controller according to the boundary state information of the flexible rod and the flexible rod model, wherein the boundary anti-saturation controller can output an actuator control value;

s140, judging whether the actuator control value reaches an actuator saturation upper limit or not according to the output of the boundary anti-saturation controller;

s150, if so, designing an auxiliary system according to the boundary state information of the flexible rod and the part exceeding the saturation upper limit of the actuator, wherein the auxiliary system is used for eliminating the saturation nonlinear influence limit of the actuator;

and S160, obtaining the gain value range of the boundary anti-saturation controller when the flexible rod is determined to be stable.

According to the flexible rod vibration suppression method based on distribution disturbance, the boundary anti-saturation controller is adopted to eliminate the influence of actuator saturation limitation and unknown distribution disturbance on the stability of the flexible rod, loss caused by elastic vibration of the flexible rod for a long time is prevented, and the flexible rod obtains higher precision in practical engineering application. In addition, the method for suppressing the vibration of the flexible rod based on the distributed disturbance, provided by the embodiment of the invention, considers the influence of the distributed disturbance force, and can overcome the defects that the flexible machine is limited by actuator saturation in an industrial process, and the external unknown distributed disturbance and the like, damages the stability of the flexible rod and causes the influence of long-time elastic vibration.

Specifically, the modeling the flexible rod based on the distributed disturbance force to obtain a flexible rod model includes:

and modeling the flexible rod according to a Lagrange equation and a Hamilton principle to obtain a system equation and boundary conditions of the Euler-Bernoulli beam.

It should be understood that the system equations and boundary conditions for a Euler-Bernoulli beam are derived from the lagrangian equation and the Hamilton principle, as shown in fig. 3; acquiring boundary state information of the flexible rod system; considering various problems of influencing the vibration and the accurate operation of the flexible rod, such as external distributed interference force, saturated actuating mechanism and the like possibly suffered by the flexible rod in the actual engineering, designing an auxiliary system; constructing a corresponding boundary anti-saturation controller by using the obtained boundary state information; obtaining the value range of the gain of the controller under the condition of ensuring the stability of the system; and judging whether the control value reaches the upper saturation limit of the actuator, and if so, compensating the saturation nonlinearity by combining with a designed auxiliary system.

Specifically, the expression of the system equation of the Euler-Bernoulli beam is as follows:

the expression of the boundary condition is:

wherein, ω (x, t) < 0, L]X [0, + ∞) → R denotes the transverse displacement of the flexible rod in space x and time T coordinates, p, T, E_IM and L represent the mass per unit length of the beam, the tension, the bending stiffness, the mass of the tip load and the length of the beam system, respectively, omega_x(x, t) and ω_t(x, t) represents the derivative of the transverse displacement ω (x, t) of the rod with respect to space x and time t, respectively, and f (x, t) represents that the spatial distribution disturbance is assumed to have an upper bound satisfyingu (t) represents an edgeA world controller; sat (u (t)) represents a saturation controller, and the expression is as follows:

wherein u is_maxAnd u_minRepresenting the upper and lower bounds of the actuator, respectively.

Specifically, the acquiring boundary state information of the flexible rod includes:

acquiring boundary velocity omega of flexible rod_t(L, t), boundary curvature ω_x(L, t) and the speed ω of the boundary bending_xt(L,t)。

The expression of the auxiliary system is as follows:

wherein z (t) represents the state of the auxiliary system, k_zα, β, and ∈ each denote a constant greater than 0, sgn (z (t)) denotes a sign function; Δ u (t) is a saturation dead-zone function, denoted as Δ u (t) sat (u (t)) u (t).

Specifically, the expression of the boundary anti-saturation controller is as follows:

u(t)＝-k_aω_t(L,t)+k_bω_x(L,t)-k_cω_xt(L,t)+k_dz(t)，

wherein k is_a,k_b,k_c,k_dBoth represent gains of the boundary anti-saturation controller greater than 0.

Specifically, when it is determined that the flexible rod is stable, obtaining an incremental value range of the boundary anti-saturation controller includes:

selecting a Lyapunov function, wherein the expression is as follows:

V(t)＝V₁(t)+V₂(t)+V₃(t)+V₄(t)，

wherein both alpha and beta are greater than 0, V₁(t) represents an energy term consisting of kinetic and potential energy, V₂(t) denotes the cross term, V₃(t) represents an energy term, V, associated with the state of the auxiliary system₄(t) represents an auxiliary item;

verifying the positive nature of the Lyapunov function to obtain:

0<α₃(V₁(t)+V₃(t)+V₄(t))≤V(t)≤α₄(V₁(t)+V₃(t)+V₄(t))，

wherein alpha is₃＝min{(1-υ),1}，α₄＝max{(1+υ),1}，

Verifying the first derivative negative nature of the Lyapunov function to time t by combining the boundary state information and the boundary anti-saturation controller, and obtaining the gain value range of the boundary anti-saturation controller;

the state of the flexible rod is obtained by the following steps:

wherein the content of the first and second substances,and when t → ∞ is reached,

due to the influence of the distributed disturbance f (x, t), the vibration of the flexible rod cannot be suppressed completely, being confined to a small area.

The effectiveness of the proposed method is illustrated below with reference to specific parameters.

Firstly, selecting the system parameters of the flexible rod as follows: L1M, M0.1 kg, E_I＝7N·m²ρ is 0.1kg/m, and T is 10N. Distribution disturbanceThe initial value of the system is selected as

Second step, consider actuator saturation limit as u_max＝5,u_minAnd (5) adopting a boundary anti-saturation controller by the controller, wherein the selected controller gain is as follows: k is a radical of_a＝6,k_b＝1,k_c＝0.04,k_d＝0.1。

FIG. 4 is a graph showing the vibration displacement of a flexible rod using a boundary anti-saturation controller under distributed disturbance conditions;

FIG. 5 is a graph showing the vibration displacement of the flexible rod boundary under distributed disturbance using a boundary anti-saturation controller.

According to the flexible rod vibration suppression method based on distributed disturbance, the influence caused by actuator saturation limitation can be effectively eliminated through the combination of the boundary saturation controller and the designed auxiliary system, and the vibration of the flexible rod can be well suppressed under the condition that the actuator is limited; and because unknown distribution disturbance is considered, the whole vibration of the flexible rod is guaranteed to be limited in a small area, and the vibration is restrained to a certain extent; in addition, the boundary state information used by the designed boundary anti-saturation controller is available, so that the method is feasible in practical application.

As another embodiment of the present invention, there is provided a flexible rod vibration suppression system based on distributed disturbance, wherein as shown in fig. 6, the system includes:

the sensor is used for acquiring boundary state information of the flexible rod;

the boundary anti-saturation controller is used for outputting a control signal of the actuator according to the boundary state information of the flexible rod;

the auxiliary system is used for eliminating the saturated nonlinear influence of the actuator according to the boundary state information of the flexible rod;

and the actuator is used for receiving the control signal of the boundary anti-saturation controller and acting on the flexible rod.

According to the flexible rod vibration suppression system based on distributed disturbance, the boundary anti-saturation controller is adopted to eliminate the influence of actuator saturation limitation and unknown distributed disturbance on the stability of the flexible rod, loss caused by elastic vibration of the flexible rod for a long time is prevented, and the flexible rod obtains higher precision in practical engineering application. In addition, the method for suppressing the vibration of the flexible rod based on the distributed disturbance, provided by the embodiment of the invention, considers the influence of the distributed disturbance force, and can overcome the defects that the flexible machine is limited by actuator saturation in an industrial process, and the external unknown distributed disturbance and the like, damages the stability of the flexible rod and causes the influence of long-time elastic vibration.

Specifically, the sensor is used for measuring the boundary state information of the flexible rod, and comprises a laser displacement sensor, an inclinometer, a pressure strain gauge and the like;

the actuator is used for receiving a control signal transmitted by the boundary anti-saturation controller and acting on the flexible rod;

the auxiliary system is used for eliminating the influence of actuator input saturation nonlinearity on the system and determining the output of the auxiliary system by judging whether the control input is in a saturation range;

the boundary anti-saturation controller is combined with a designed auxiliary system to eliminate the influence of actuator saturation on the system aiming at the limited condition of the actuator.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.