Output end motion regulation and control method based on connecting rod mechanism

Abstract

The invention relates to an output end motion regulation and control method based on a connecting rod mechanism. The regulation and control method comprises the following steps: modeling analysis of the connecting rod mechanism; fitting the implicit function equation and planning and solving to obtain an explicit function equation between the input end and the output end; output end parameters are defined to reversely control input end parameters to form a closed loop. According to the method, the relation expression of the input end and the output end of the connecting rod mechanism is fitted, the system model is built in combination with the Simulink module, and the change curve corresponding to the parameters of the input end can be obtained through the parameter values of the input end and the output end. The input end is controlled according to the changing curve, the output end of the connecting rod can be controlled to move, the output end can move in any wanted mode, and compared with traditional closed-loop control, the control mode is simple, lag is avoided, adaptability is wide, and working precision can be improved.

Description

Technical Field

[0001] The present invention relates to the field of automation control technology, and in particular to a control method based on output end movement of a connecting rod mechanism. Background Art

[0002] As an important mechanical transmission device, the connecting rod mechanism is composed of several rigid components connected by low pairs. These components achieve relative motion through the constraints of the kinematic pairs, so that the motion of one component is transmitted to other components to realize the motion of the entire mechanism. Based on the relative motion and constraint relationship between the components, different motion trajectories and speed characteristics can be achieved by changing the parameters such as the size, shape and type of kinematic pairs of the connecting rod mechanism. Therefore, the connecting rod mechanism has a wide range of applications. It is widely used in various mechanical equipment and systems, and can realize complex motion transformation and transmission to meet the working requirements of various mechanical equipment.

[0003] However, when the connecting rod mechanism is transmitting motion, the motion at the output end often changes irregularly. Especially in situations where high-precision control is required, this will lead to cumulative motion errors, increase friction and wear of the mechanism, and further affect the accuracy of the motion, thereby reducing mechanical efficiency.

[0004] In addition, in order to achieve changes in the motion laws of the output end, traditional connecting rod mechanisms often add sensors at the output end to provide real-time feedback of output end information to regulate input end information, but this has limitations in harsh environments such as high temperatures and is difficult to apply. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a control method based on the output end movement of a connecting rod mechanism to solve one or more problems in the prior art.

[0006] To achieve the above object, the technical solution of the present invention is as follows: A control method based on the output end movement of a connecting rod mechanism, the control method comprising the following steps: Modeling and analysis of linkage mechanism; The implicit function equation is fitted and solved in a planned manner to obtain the explicit function equation between the input and output ends of the linkage mechanism; the output end parameters are defined to reversely control the input end parameters to form a closed loop.

[0007] Furthermore, the modeling analysis of the linkage mechanism includes the following steps: Establish a coordinate system with the fixed point of the linkage mechanism as the origin; Orthogonal decomposition of each intersection or end point of the linkage mechanism according to the coordinate system yields a relational expression; The implicit function equation is established by selecting the relationship between multiple intersection points or end points and then combined to finally obtain the implicit function equation between the input end and the output end of the linkage mechanism.

[0008] Furthermore, the relationship equations are all about the length of the connecting rod mechanism, the angles between each intersection or endpoint, and the coordinate relationship between each intersection or endpoint, wherein the length of the connecting rod mechanism is a known quantity.

[0009] Furthermore, the step of defining the output end parameter to reversely control the input end parameter to form a closed loop includes the following steps: Define the output parameter value; The change curve of input terminal parameters is obtained through Simulink model analysis and calculation; The input parameters are adjusted according to the change curve to control the output movement.

[0010] Compared with the prior art, the beneficial technical effects of the present invention are as follows: The present invention establishes a fitting of the relationship between the input and output ends of the connecting rod mechanism, and combines the Simulink module to build a system model. Through the parameter values ​​of the input and output ends, the change curve corresponding to the input end parameter can be obtained. That is, by controlling the input end according to this change curve, the movement of the connecting rod output end can be controlled, and the output end can be allowed to move in any desired way. Compared with the traditional closed-loop control, the control method is simple, has no lag, has wide adaptability, and is conducive to improving the working accuracy; in addition, while effectively realizing the closed-loop control of the connecting rod mechanism, the present invention can also avoid the problem that the traditional connecting rod mechanism cannot set a sensor at the output end in a harsh environment to realize the change of the output end motion law, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic flow chart of a method for controlling the output end movement of a connecting rod mechanism according to an embodiment of the present invention is shown.

[0012] Figure 2 A structural schematic diagram of a connecting rod mechanism according to an embodiment of the present invention is shown in a method for controlling the output end movement of the connecting rod mechanism. Figure 3 A schematic diagram of implicit function equation fitting of a control method based on output end motion of a connecting rod mechanism according to an embodiment of the present invention is shown.

[0013] Figure 4 A schematic diagram of a Simulink model of a method for controlling output end motion based on a connecting rod mechanism according to an embodiment of the present invention is shown.

[0014] Figure 5 A curve diagram showing the change of input end velocity over time when the output end angular velocity is constant in a method for controlling the output end motion based on a connecting rod mechanism according to an embodiment of the present invention.

[0015] Figure 6A curve chart of measured data of a control method based on output end movement of a connecting rod mechanism according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present invention clearer, the following is a further detailed description of a control method based on the output end movement of a connecting rod mechanism proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated in the accompanying drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0017] See also Figure 1 The control method based on the output end movement of the connecting rod mechanism of this embodiment comprises the following steps: Step 1: Modeling and analysis of the linkage mechanism.

[0018] For details, please continue to refer to Figure 2 , taking the connecting rod mechanism in this embodiment as an example for explanation.

[0019] Step 1.1: Establish a coordinate system with the fixed point of the linkage as the origin.

[0020] according to Figure 2 As shown, a coordinate system in the x and y directions is established with point O as the origin, and point A is used as the input end point and connecting rod FG is used as the output end. Preferably, in this embodiment, the ordinate y of point A is A In addition, based on different connecting rod mechanisms, there are one or more fixed points, and any one of them can be selected to implement the technical solution of the present invention.

[0021] Step 1.2: Decompose each intersection or end point of the linkage mechanism orthogonally according to the coordinate system to obtain the relationship.

[0022] The relationship equations are all about the length of the connecting rod mechanism, the angles between each intersection or endpoint, and the coordinate relationship of each intersection or endpoint, wherein the length of the connecting rod mechanism is a known quantity.

[0023] Depend on Figure 2It can be seen that in this embodiment, there are connecting rods OF, AE, EG and FG, which are combined to form endpoints O and A, and intersections D, E, F, G. The above endpoints and intersections can be orthogonally decomposed into the relationship in the x and y directions with O as a reference. In order to obtain the relationship between the input end and the output end, the vector expressions with AOD and DEFG as the connection are selected here as shown in the following formula 1:

[0024] Where: r OD is the vector from point O to point D, r OA is the vector from point O to point A, r AE is the vector from point A to point E, r DE is the vector from point D to point E, r EG is the vector from point E to point G, r DF is the vector from point D to point F, r FG is the vector from point F to point G.

[0025] Furthermore, the following equation 2 is obtained by orthogonal decomposition of equation 1 in the x and y directions:

[0026] Where: l AD is the length from point A to point D on connecting rod AE, α AE for Figure 2 The angle between the connecting rod AE and the negative x direction is l OD is the length from point O to point D on the connecting rod OF, α OF for Figure 2 The angle between the connecting rod OF and the positive direction of x is shown in A is the horizontal movement distance of point A, y A is the vertical distance from point A to the x-axis, x E is the horizontal distance of point E from the y-axis, l EG is the length of connecting rod EG, α EG for Figure 2 The angle between the connecting rod EG and the positive direction of the x-axis, x F is the horizontal distance between point F and the y-axis, l FG is the length of the connecting rod FG, α FG for Figure 2 The angle between the connecting rod FG and the positive direction of the x-axis, y E is the vertical distance of point E from the x-axis, y F is the vertical distance of point F from the x-axis.

[0027] Furthermore, for Formula 2, the horizontal and vertical coordinates of points E and F are as shown in Formula 3 below:

[0028] Where: (x A ,y A ) is the coordinate value of point A in the xOy coordinate system, (x E ,y E ) is the coordinate value of point E in the xOy coordinate system, (x F ,y F ) is the coordinate value of point F in the xOy coordinate system, l AE is the length of connecting rod AE, l OF is the connecting rod OF length, α AE for Figure 2 The angle between the connecting rod AE and the negative x direction is α OF is the angle between the connecting rod OF and the x direction.

[0029] Step 1.3: Select multiple intersection points or endpoints to establish implicit function equations and solve them simultaneously to finally obtain the implicit function equation between the input and output ends of the linkage mechanism.

[0030] Combining the above equations 1 to 3, we can establish the lateral displacement position x of point A. A Respectively with the angle α AE , α OF and α FG The implicit function equation of , the corresponding relationship is shown in equation 4:

[0031] Where: (x A ,y A ) is the coordinate value of point A in the xOy coordinate system, (x E ,y E ) is the coordinate value of point E in the xOy coordinate system, (x F ,y F ) is the coordinate value of point F in the xOy coordinate system, l AD is the length from point A to point D on connecting rod AE, l AD is the length from point O to point D on the connecting rod OF, l FG is the length from point F to point G on the connecting rod FG, l EG is the length of connecting rod EG, α AE for Figure 2 The angle between the connecting rod AE and the negative x direction is α OF is the angle between the connecting rod OF and the x direction, α FG for Figure 2 The angle between the connecting rod FG and the positive direction of the x-axis is shown.

[0032] Step 2: Fit the implicit function equation and plan the solution to obtain the explicit function equation between the input and output ends of the linkage mechanism.

[0033] From the above, we can know that the length of each connecting rod and the ordinate y of point A in formula 4 are A All are known quantities. The deflection angles of connecting rods AE, OF, and EG are related to x A All are nonlinearly related. In order to obtain the output connecting rod angle α FG With x A The explicit function expression of Equation 4 is used to perform planning solution and nonlinear fitting on the implicit function equation. The fitting results are shown in Figure 3 The results are shown in Table 1.

[0034] Table 1

[0035] Furthermore, regarding x A With α FG After fitting the equation h(x A ) to obtain the moving speed v of point A A and the output end connecting rod FG speed ω FG The correlation is shown in Formula 5:

[0036] Where: C １ , C ２ , C ３ All are fixed values ​​as shown in Table 1, v A is the moving speed of point A, ω FG is the speed of the connecting rod FG at the output end.

[0037] Step 3: Define the output end parameters to reversely control the input end parameters to form a closed loop.

[0038] In particular, for different structures of the connecting rod mechanism itself or different analysis methods, such as an open-loop connecting rod mechanism, it is also possible to directly apply step 3 instead of using steps 1 and 2 of this embodiment to model and analyze the connecting rod mechanism, perform orthogonal decomposition and combine the fitting method to obtain the explicit function equation between the input and output ends of the connecting rod mechanism.

[0039] Please continue reading Figure 4 A graphical model is built based on Simulink. In the figure, 1 / S represents the integral calculation process.

[0040] Step 3.1: Define the output parameter values.

[0041] In this embodiment, the speed of the output end connecting rod FG is set to a constant value and moves at a uniform speed, that is, ω FG Constant.

[0042] Step 3.2: Analyze and calculate the change curve of the input parameters through the Simulink model.

[0043] According to the above formula 5, it is introduced into the Simulink model and solved by calculation to obtain FG When constant, v A The curve of speed changing with time.

[0044] Specifically, as shown in Table 2 below, FG When constant, the speed v at the input A Data over time: Table 2

[0045] Further, according to Table 2 above, we can get FG When constant, the speed v at the input A The curve of change over time, such as Figure 5 shown.

[0046] Step 3.3: Adjust the input parameters according to the change curve to control the output movement.

[0047] According to the obtained v A The curve of velocity changing with time is Figure 5 The input speed is regulated at the input end, and the output end ω FG The rotation speed is constant to achieve the effect of uniform motion.

[0048] Specifically, as shown in Table 3 below, the changes in the angular velocity of the output end caused by the uniform speed and speed regulation of the input end are measured under the condition of setting the same time interval: Table 3

[0049] The curve diagram further obtained from the data in Table 3 above is as follows Figure 6 As shown, it is obvious that after the input end is adjusted in speed by this embodiment, the change of the angular velocity of the output end is relatively stable, which effectively improves the working accuracy in high-demand situations.

[0050] Preferably, the present invention belongs to active control, which requires the input end to move according to a given curve so that the output end can achieve the desired movement effect. If the load on the output end changes greatly, the actual speed of the input motor will be inconsistent with the given value. In this case, based on the method proposed in the present invention, a speed sensor can be added to the connecting rod mechanism motor to form a small closed loop, ensuring that the motor moves strictly according to the given curve, and the applicability is further enhanced.

[0051] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A control method based on the output end movement of a connecting rod mechanism, characterized in that: The control method comprises the following steps: Modeling of linkage mechanisms; Fit the implicit function equation and plan the solution to obtain the explicit function equation between the input end and the output end of the linkage mechanism; Define the output end parameters to reversely control the input end parameters to form a closed loop.

2. A control method based on the output end movement of a connecting rod mechanism as claimed in claim 1, characterized in that: The modeling analysis of the linkage mechanism includes the following steps: Establish a coordinate system with the fixed point of the linkage mechanism as the origin; Orthogonal decomposition of each intersection or end point of the linkage mechanism according to the coordinate system yields a relational expression; The implicit function equation is established by selecting the relationship between multiple intersection points or end points and then combined to finally obtain the implicit function equation between the input end and the output end of the linkage mechanism.

3. A control method based on the output end movement of a connecting rod mechanism as claimed in claim 2, characterized in that: The relationship equations are all about the length of the connecting rod mechanism, the angles between each intersection or endpoint, and the coordinate relationship of each intersection or endpoint, wherein the length of the connecting rod mechanism is a known quantity.

4. A control method based on the output end movement of a connecting rod mechanism as claimed in claim 3, characterized in that: The step of defining the output end parameter to reversely control the input end parameter to form a closed loop includes the following steps: Define the output parameter value; The change curve of input terminal parameters is obtained through Simulink model analysis and calculation; The input parameters are adjusted according to the change curve to control the output movement.

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