Disclosure of Invention
The invention mainly aims to provide a rigid-flexible coupling motion platform control method based on disturbance force measurement compensation, aiming at realizing the purposes of no need of switching control, reduction of control complexity and finally realization of high-speed precise motion.
In order to achieve the above purpose, the invention provides a rigid-flexible coupling motion platform control method based on disturbance force measurement compensation, which specifically comprises the following steps:
s1: obtaining the rigidity and the damping of the flexible hinge through modeling and testing;
s2, establishing a closed-loop control system of the platform rigid body by taking the speed and the displacement of the platform rigid body as feedback and taking a driving unit of the platform rigid body as an actuator;
s3: detecting the speed and the displacement of the frame rigid body and respectively making difference with the speed and the displacement of the platform rigid body to obtain the speed difference and the displacement difference between the frame rigid body and the platform rigid body;
s4: multiplying the speed difference and the displacement difference obtained in the step S3 by the damping and the rigidity of a flexible hinge respectively to obtain the disturbance force of the flexible hinge on the platform rigid body;
s5: and dividing the disturbance force obtained in the step S4 by a transfer function from the control quantity to the driving force to convert the disturbance force into an equivalent control quantity, multiplying the equivalent control quantity by a proportional gain to compensate the equivalent control quantity into the control quantity of the platform rigid body, and converting the control quantity into a disturbance-free rigid body platform control system.
Preferably, a control object of the control method is a rigid-flexible coupling platform, and the rigid-flexible coupling platform includes the frame rigid body mounted on the mechanical guide rail and a platform rigid body connected to the frame rigid body through a flexible hinge.
Preferably, the frame rigid body and the platform rigid body are respectively mounted with displacement speed detection units.
Preferably, the platform rigid body mounts a drive unit.
Preferably, the frame rigid body is provided with a driving unit, the speed and displacement of the frame rigid body are used as feedback in the step S2, and the driving unit on the frame rigid body is an actuator and establishes a closed-loop control system of the frame rigid body.
Preferably, a control system using the control method is composed of a control object, a displacement speed detection unit, a driving unit and a controller.
Preferably, the proportional gain of S5 is used to adjust the measurement error, and the proportional gain is 1 without error.
Preferably, the information required in the control method is obtained by measurement, and if the information cannot be obtained by measurement, the information is obtained by model calculation.
Compared with the prior art, the technical scheme of the invention has the following advantages:
the technical scheme of the invention is based on the design of a rigid-flexible coupling platform, the disturbance of the friction force of a mechanical guide rail is converted into the dynamic deformation of the flexible hinge, and the rigid body of the platform is equivalent to an ideal frictionless platform through the compensation control of the elastic force and the damping force of the flexible hinge, so that the high-speed precise motion can be realized, the switching control is not needed, and the control complexity is reduced.
Detailed Description
The technical solutions 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 of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
The invention provides a rigid-flexible coupling motion platform control method based on disturbance force measurement compensation.
The control object of the rigid-flexible coupling motion platform control method based on disturbance force measurement compensation is a rigid-flexible coupling platform, and mainly comprises a frame rigid body and a platform rigid body, wherein the frame rigid body is arranged on a mechanical guide rail, and the platform rigid body is arranged on the frame rigid body through a flexible hinge.
The frame rigid body and the platform rigid body are respectively provided with a displacement speed detection unit, the platform rigid body is provided with a driving unit, and the frame rigid body can be provided with the driving unit selectively. The whole control system consists of a control object, a displacement speed detection unit, a driving unit and a controller.
The invention relates to a rigid-flexible coupling motion platform control method based on disturbance force measurement compensation, which specifically comprises the following control steps:
s1: obtaining the rigidity and the damping of the flexible hinge through modeling and testing;
s2, establishing a closed-loop control system of the platform rigid body by taking the speed and the displacement of the platform rigid body as feedback and taking a driving unit of the platform rigid body as an actuator;
s3: detecting the speed and the displacement of the frame rigid body and respectively making difference with the speed and the displacement of the platform rigid body to obtain the speed difference and the displacement difference between the frame rigid body and the platform rigid body;
s4: multiplying the speed difference and the displacement difference obtained in the step S3 by the damping and the rigidity of the flexible hinge respectively to obtain the disturbance force of the flexible hinge on the platform rigid body;
s5: the disturbance force obtained in step S4 is divided by the transfer function from the control amount to the driving force to be converted into an equivalent control amount, and then multiplied by a proportional gain to be compensated into the control amount of the rigid platform, so as to be converted into a rigid platform control system without disturbance.
In the technical solution of the present invention, if the frame rigid body is also provided with a driving unit, the speed and displacement of the frame rigid body are used as feedback in the above step S2, and the driving unit on the frame rigid body is used as an actuator and establishes a closed-loop control system for the frame rigid body, so that the speed of the platform can be increased and the disturbance of the flexible hinge can be reduced.
Wherein, the proportional gain of the step S5 in the technical solution of the present invention is used for adjusting the measurement error, and the proportional gain is 1 when there is no error. The information required in the control method can be obtained through measurement as much as possible, and can be obtained through model calculation if the information cannot be obtained through measurement.
The technical scheme of the invention is that the rigid-flexible coupling motion platform control method based on disturbance force measurement compensation converts the disturbance of the friction force of the mechanical guide rail into the dynamic deformation of the flexible hinge, and the rigid body of the platform is equivalent to a frictionless ideal platform through the compensation control of the elastic force and the damping force of the flexible hinge so as to realize high-speed precise motion without switching control.
Example 1
In the embodiment of the invention, the rigid-flexible coupling platform mainly comprises a mechanical guide rail, a frame rigid body, a flexible hinge and a platform rigid body, and X is set
M,X
mRespectively the displacement of the frame rigid body and the platform rigid body,
the speed of the frame rigid body and the platform rigid body respectively, M and M are the mass of the frame rigid body and the platform rigid body respectively, k and c are the rigidity and the damping of the flexible hinge respectively, and F
M,F
mDriving forces acting on the frame rigid body and the platform rigid body, respectively, for the driving unit, f
μIs the friction between the rigid frame body and the mechanical guide rail.
The rigid-flexible coupling motion platform control method based on disturbance force measurement compensation in the embodiment is single-drive motion control, wherein a platform rigid motion mechanical response equation is as follows:
the frame rigid motion mechanics response equation is:
the stress of the flexible hinge is as follows:
after disturbance compensation is carried out, the dynamic response equation of the platform rigid body is as follows:
substituting the flexible hinge stress formula (3) into a platform rigid dynamic response equation, namely formula (4), to obtain an equivalent dynamic response equation of the platform rigid body as follows:
in this embodiment, the equivalent dynamic response equation of the platform rigid body obtained by the formula (5) is an ideal frictionless platform, in this embodiment, the frame rigid body overcomes the friction motion under the action of the acting force Δ f of the flexible hinge, and the disturbance of the friction causes the change of the acceleration of the frame platform and the deformation of the flexible hinge, so that the disturbance of the friction force, which cannot be measured, is converted into the action of the flexible hinge, which can be measured.
Example 2
In the embodiment of the invention, the rigid-flexible coupling platform mainly comprises a mechanical guide rail, a frame rigid body, a flexible hinge and a platform rigid body, and X is set
M,X
mRespectively the displacement of the frame rigid body and the platform rigid body,
the speed of the frame rigid body and the platform rigid body respectively, M and M are the mass of the frame rigid body and the platform rigid body respectively, k and c are the rigidity and the damping of the flexible hinge respectively, and F
M,F
mDriving forces acting on the frame rigid body and the platform rigid body, respectively, for the driving unit, f
μIs the friction between the rigid frame body and the mechanical guide rail.
The rigid-flexible coupling motion platform control method based on disturbance force measurement compensation in the embodiment is dual-drive motion control, wherein a platform rigid motion mechanical response equation is as follows:
the frame rigid motion mechanics response equation is:
wherein FMThe speed displacement deviation of the moving target of the platform rigid body and the frame rigid body is obtained by calculation according to the control rule.
The stress of the flexible hinge is as follows:
after disturbance compensation is carried out, the dynamic response equation of the platform rigid body is as follows:
substituting the flexible hinge stress formula (8) into a platform rigid dynamic response equation, namely a formula (9), to obtain an equivalent dynamic response equation of the platform rigid body as follows:
the embodiment adopts a dual-drive motion control scheme, the frame rigid body is driven to move by the driving force on the frame rigid body, and the driving forces of the frame rigid body and the frame rigid body can realize higher-speed motion after being superposed. In addition, the speed displacement deviation between the frame rigid body and the platform rigid body is reduced due to the movement of the frame rigid body, so that the dynamic deformation disturbance of the flexible hinge can be effectively reduced, and the performance is better.
Example 3
The platform parameters of this embodiment are:
core platform mass m
|
2kg
|
Frame mass M
|
2kg
|
Coefficient of friction
|
0.2
|
Flexible hinge stiffness k
|
2000N/mm
|
Flexible hinge damping c
|
100N/mm/s
|
Optimized Kp
|
35702280.82
|
Optimized Ki
|
7172.72
|
Optimized Kd
|
349977.10 |
Referring to fig. 2 to 4, when the conventional PID method and the ADRC method using the spring damping force compensation are used, the maximum error of the position tracking error curve is reduced by one order of magnitude from 9e-8 to 9e-9 as shown in fig. 2.
When the PID control is adopted, if the model parameter changes, the tracking error changes with the change, as shown in fig. 3, however, the tracking error hardly changes with the change of the model by the Active Disturbance Rejection Control (ADRC) method of the technical solution of the present invention adopting the spring damping force compensation, and the good disturbance rejection performance is shown, as shown in fig. 4.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.