CN103302162A - Mould positioning method based on feature distance - Google Patents

Abstract

A mold positioning method based on characteristic distance, the method has five major steps as follows: 1: Initial placement of the mold (1) place the block, (2) place the mold; 2: move the equipment (1) determine the coordinates, (2) equipment Anti-solution, (3) drive equipment; three: measurement calculation (1) distance measurement, (2) geometric calculation; four: mold positioning calculation; five: correct NC code for drawing. According to the equipment characteristics of the ACB FET series CNC horizontal drawing machine, the method uses the position of the clamp to reverse the motion parameters of the drawing machine to drive the equipment to move, and uses the distance between the clamp feature point and the mold feature point to calculate the coordinates and space of the mold feature point Position, and then according to the position of the mold, redesign the drawing CNC code to achieve accurate skin drawing. The mold placement process formulated by the method can increase the error redundancy of the mold placement, reduce the mold placement time and the use of positioning tooling, and improve the production efficiency of aircraft skin drawing.

Description

A Die Positioning Method Based on Feature Distance

(1) Technical field

The invention relates to a positioning method for determining the placing position of a mold in the stretch forming process of an aircraft skin part. In particular, it involves the positioning method of the mold placement position before transverse stretch forming using the CNC stretch forming machine of the ACB FET series. The invention belongs to the technical field of aviation aircraft manufacturing.

(2) Background technology

Skin parts are exterior parts that form and maintain the aerodynamic shape of an aircraft. Stretch forming (referred to as stretch forming) is a process method of overmolding with a mold, and it is one of the main forming methods for forming aircraft skin parts. The two sides of the wool are clamped by the clamp of the equipment, and the movement of the mold and the clamp is used to make the wool produce uneven stretching deformation, and the mold is covered to make the wool and the mold fit.

The process parameters of the drawing mainly include the elongation of the wool and the cladding angle of the clamp. Through the process parameters and the actual shape of the drawing die, the movement track of the clamp is calculated (as shown in Figure 1). ACB FET series CNC stretching machine is a horizontal stretching machine produced by ACB GEC ALSTHOM in France. The structure of this series of stretching machines is similar. According to the tonnage, it is divided into FET400, FET600, FET1200 and so on. The skin stretching is carried out by the numerical control stretching machine, and the precise control of the movement track of the clamp by the equipment is used to realize the precise forming process. The size of the aircraft skin stretching die ranges from a dozen centimeters to more than a dozen meters, and the weight of the stretching die for large skin parts is as much as 100 tons. For the installation of large-scale drawing molds, the mold is usually lifted by a crane, and then multiple people assist to install the mold to the designated position of the drawing equipment for production. Getting molds into pre-set positions often required multiple placements and fine-tuning, setups often lasted hours, and final placements varied widely. The uncertainty of the placement of the mold becomes an uncertain factor affecting the quality of skin forming, thereby affecting the forming accuracy of skin stretching. Therefore, a method for quickly locating the mold is needed to locate the actual position of the mold, and according to the position of the mold at that time, correct the process parameters and numerical control codes, so that the movement track of the clamp conforms to the actual situation, making the drawing process more accurate, and ensuring the quality of the parts Forming quality.

(3) Contents of the invention

1. Purpose:

The purpose of the present invention is to provide a mold positioning method based on characteristic distance. According to the characteristics of the CNC drawing equipment, the method uses the precise coordinates of the feature points on the clamp to measure the relative distance to the feature points on the mold, determines the position error of the mold, corrects the CNC code for equipment processing, and improves the accuracy of forming. and the quality of parts.

2. Technical solution:

A kind of mold positioning method based on characteristic distance of the present invention, its steps are as follows:

Step 1: Initial Mold Placement

The initial placement of the stretch forming mold for skin parts is to place the actual mold in the coordinate system of the stretching equipment, which is the preparation for the positioning measurement of the mold and the stretching process, as shown in Figure 2;

In the actual production process of the factory, the mold is placed on the standard block, and placed together with the block in the coordinate system of the drawing equipment. The standard block is a standard part made by the factory, which is distinguished by the height and the weight of the mold that the block can bear. The initial placement of the mold first selects the standard block according to the outer dimension and quality of the skin pulling mold; then places the block and the mold according to the factory process regulations, and measures the levelness of the top surface of the block to ensure that the block is placed horizontally. Record the height H of the pad and the height h between the feature point of the mold and the bottom surface of the mold.

Step Two: Sports Equipment

The moving equipment is to move the equipment clamp of ACB FET series horizontal drawing machine to the designated position, so that the clamp feature point and the mold feature point are in the same horizontal plane, which is convenient for distance measurement.

(1) Determine the coordinates

Determine the coordinate position of the clamp feature point during measurement, and determine the height (Z coordinate) of the horizontal plane where the mold feature point is located based on the height of the pad and the distance between the mold feature point and the bottom surface of the mold; through the external dimension of the mold and the theoretical placement Determine the position of the clamp feature point on the X axis (X coordinate); according to the position of the clamp feature point on the clamp, the Y coordinate of the clamp feature point can be obtained, as shown in Figure 3;

(2) Device anti-solution

The motion inverse solution of the ACB FET series horizontal drawing machine is to solve the length of each actuator on the parallel mechanism, that is, the motion parameters of the equipment, through the coordinate position of the clamp feature point and according to the mechanical characteristics of the drawing equipment. ACBFET series CNC horizontal drawing machine is mainly used for horizontal drawing forming of aircraft skin parts. , two longitudinal actuating cylinders form two pairs of four-bar parallel mechanisms. Simplify the calculation process of the motion inverse solution, set the axis of the clamp to be parallel to the Y axis, so only need to calculate the position of the clamp in the ZX plane, that is, only need to calculate the elongation of the Z actuator and the A actuator, such as As shown in Figure 6;

(3) Drive equipment

The elongation of each actuator of the stretching machine obtained by reverse analysis of the ACB FET series horizontal stretching machine is input into the interface of the CNC horizontal stretching machine control system to drive the equipment to move, so that the clamp moves to the designated position for distance measurement.

Step 3: Measure and calculate

The measurement process is to measure the distance from each feature point of the clamp to each feature point of the mold, and then obtain the coordinates of the feature points through geometric calculation.

(1) Distance measurement

Mark two feature points on the two clamps on the left side (the side where X is negative) and the right side (where X is positive), which are denoted as P _L1 , P _L2 and P _R1 , P _R2 ; Mark two feature points on , denoted as T _L and T _R . Measure the distances from P _L1 and P _L2 to T _L and the distances from P _R1 and P _R2 to T _R respectively, as shown in Fig. 7 . Due to the large error of common measurement methods, such as tape measure, long rope, etc., the use of higher precision measurement methods, such as three-coordinate measuring instrument, laser tracker, etc., can improve the mold positioning accuracy;

(2) Geometric calculation

After step 2 drives the equipment to move, the feature points on the clamp and the feature points of the mold are in the horizontal plane at the same height, so the mold positioning calculation can use the solution method of plane geometry to calculate the coordinates of the feature points of the mold, as shown in Figure 8.

It can be seen from Figure 8 that, taking the left side as an example, the specific coordinates of the mold feature point T _L can be determined by the intersection of a circle with P _L1 as the center and L _L1 as the radius and a circle with P _L2 as the center and L _L2 as the radius. Similarly, the specific coordinates of the right mold feature point T _R can be determined.

Step 4: Die positioning calculation

The specific coordinates of the mold feature points obtained through measurement and calculation are compared and calculated with the theoretical coordinates of the mold feature points, and the translation vector and rotation angle in the plane where the pad block on the top surface of the mold is placed are obtained, as shown in Figure 9.

Step 5: Correct the NC code for drawing

From the transformation parameters calculated in step 4, the theoretical mold is transformed into the actual mold placement position, and the new mold position is used as the benchmark, and the process parameters are applied to generate the equipment CNC code that matches the actual mold position. Input the CNC code of the drawing equipment into the ACB FET horizontal drawing machine, run the drawing machine with no load, and check whether the movement of the equipment is consistent with the designed process parameters. After the check is correct, carry out skin pulling.

Through the above five steps, the rapid positioning of the spatial position of the drawing die is realized. The method of correcting the stretching track through the actual position of the mold makes the stretching forming process of the skin part conform to the actual situation, so that the influence of the deviation of the mold placement on the forming accuracy of the part is minimized, the use of positioning tools is reduced, and the aircraft is guaranteed The precision with which skinned parts are produced.

Among them, the method of solving the motion parameters of the equipment through the coordinates of the feature points of the clamps described in step 2 uses the characteristics of the equipment mechanism and the precise control ability of the CNC drawing equipment to realize the generation of CNC codes through the movement trajectory of the clamps. The process is precisely controlled.

Wherein, the method for determining the position of the feature point of the mold by measuring the distance between the feature points described in step 3 realizes the determination of the spatial position of the mold through simple measurement and geometric calculation. The method is simple, practical and easy to implement.

3. Advantages and effects:

The present invention is based on the positioning method of a kind of aircraft skin stretching mold of numerical control stretching equipment, is according to the characteristic of numerical control stretching machine, obtains the coordinate of clamp characteristic point through the movement parameter of stretching machine, measures clamp characteristic point and mold The distance of the feature points is calculated to obtain the coordinates of the feature points of the mold to correct the position of the mold, and then according to the corrected mold position, redesign the stretching CNC code according to the process parameters to achieve accurate skin stretching. This method formulates the mold placement process in the aircraft skin stretching production process, increases the error redundancy of the mold placement, reduces the mold placement time and the use of positioning tooling, and improves the aircraft skin stretching production efficiency; And the position of the mold is corrected by measurement, so that the NC code is more in line with the current situation, which can improve the forming quality of the skin parts, reduce the scrap rate, and make the horizontal stretching of the skin easier to realize digital production.

(4) Description of drawings

Fig.1 Schematic diagram of skin tensile loading process

Figure 2 Schematic diagram of mold placement

Figure 3 Schematic diagram of clamp movement position

Figure 4 Outline schematic diagram of ACB FET series CNC horizontal drawing machine

Figure 5. Diagram of the mechanism on one side of the ACB FET device

Figure 6 ACB FET device reverse solution schematic diagram

Figure 7 Schematic diagram of feature point position and size measurement

Figure 8 Schematic diagram of calculating the position of the mold positioning feature points

Figure 9 Schematic Diagram of Die Positioning Transformation Calculation

Fig. 10 method flow chart of the present invention

The symbols in the figure are explained as follows:

：模具左侧特征点理论位置

：模具右侧特征点理论位置TO：模具特征点连线中点

：模具特征点连线中点理论位置O: Origin of the equipment coordinate system X: X-axis of the equipment coordinate system Y: Y-axis of the equipment coordinate system Z: Z-axis of the equipment coordinate system T _L : Feature points on the left side of the mold (X negative side) T _R : Feature points on the right side of the mold (One side in the positive X direction) h: Distance from the mold feature point to the bottom surface of the mold H: Pad height P _L : Feature point of the left clamp (on the negative side of X direction) P _R : Feature point of the right clamp (in the positive direction of X) One side) W: mold width D: distance between clamp and mold A ₀ : A ₀ joint point A _Ⅰ : A _Ⅰ joint point Y ₀ : Y ₀ joint point Y _Ⅰ : Y _Ⅰ joint point Z ₀ : Z ₀ joint point Z _Ⅰ : Z _Ⅰ joint point Z _Ⅱ : Z _Ⅱ joint point X ₀ : X ₀ joint point X _Ⅰ : X _Ⅰ joint point X _Ⅱ : X _Ⅱ joint point O _ZA : Intersection point of actuator Z, A plane and clamp jaw O _XY : Intersection point P of the actuator X, Y plane and the jaw of the clamp P _L1 : Feature point 1P of the left clamp _L2 : Feature point 2P of the left clamp _R1 : Feature point 1P of the right clamp _R2 : Right clamp Feature point 2: angle between equipment ∠O _ZA A ₁ A _O β: angle between equipment ∠O _ZA A ₁ Z ₁ θ: angle between equipment ∠A _O O _ZA A ₁

: The theoretical position of the feature point on the left side of the mold

: The theoretical position of the feature point on the right side of the mold TO: The midpoint of the line connecting the feature points of the mold

: The theoretical position of the midpoint of the mold feature point connection line

(5) Specific implementation methods

As shown in Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, and Figure 10, the specific implementation steps of the mold positioning method based on the characteristic distance are as follows:

Step 1: Initial Mold Placement

The initial placement of the stretch forming mold for skin parts is shown in Figure 2. The placement process can be divided into placing cushion blocks and placing molds in sequence.

1. Place the block

The spacer is a factory-made standard part, which is divided according to the height and the weight it can bear, and its height and top plane meet the accuracy requirements of the process plan. First, determine the model of the cushion block according to the overall size, quality and drawing track of the mold, and select the cushion block. When placing the block, place the block on the designated position of the pull-shaped equipment according to the process regulations, so that the symmetrical plane of the block is parallel to the YZ plane of the equipment coordinates. After placement, measure the levelness of the top plane of the chock to ensure that the top surface of the chock is level. Record the height H of the chock.

2. Place the mold

Before placing the mold, first measure the height h of the feature point of the mold from the bottom surface of the mold, check the position of the feature point, and compare it with the theoretical digital model of the mold to ensure that the actual mold is consistent with the digital model and prevent the mold from changing due to other reasons, such as mold modification , The rigidity of the mold is not enough to change, etc. Then place the mold on the block, try to make the mold placed in the coordinate center of the drawing equipment, and the mold feature plane and the coordinate plane of the equipment are as parallel as possible. After placing the mold, measure the height of the bottom surface of the mold and the levelness of the bottom surface of the mold to ensure that the height and levelness of the mold meet the requirements.

Step Two: Sports Equipment

The moving equipment is to move the equipment clamp of ACB FET series horizontal drawing machine to the designated position, so that the clamp feature point and the mold feature point are in the same horizontal plane, which is convenient for distance measurement. First determine the position coordinates of the clamps of the stretching machine, and then decipher the movement parameters of the stretching machine according to the position of the clamps, and then drive the stretching machine to move the clamps to the specified position.

1. Determine the coordinates

According to the schematic diagram in FIG. 3 , determine the coordinate positions to which the feature points of the left and right clamps need to move. Let the feature points of the left and right clamps be . From the measurement records of step 1, it can be seen that the Z coordinate of the clamp feature point is the sum of the height of the spacer and the height of the mold feature point from the bottom surface of the mold, namely:

${{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Let the mold width be W, assuming that the mold is placed in the center, and the distance between the clamp position and the two sides of the mold is D, that is:

${{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; W</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; W</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

The coordinates of the clamp feature points are obtained from formulas (1) and (2).

2. Reverse solution of equipment

In order to simplify the calculation and measurement, the posture of the clamp is parallel to the Y axis when measuring the distance, as shown in Figure 5, that is, the x and y coordinates of P _L1 , O _ZA , O _XY , and P _L2 are the same, and the actuator Z and The amount of elongation of X is the same, and the amount of elongation of cylinder A and Y is the same.

The inverse calculation of the equipment is to calculate the elongation of the equipment barrel based on the known coordinates of the O _ZA point. Take the left side of the equipment, that is, the side in the negative X direction, as an example, as shown in Figure 6. Analyzing the schematic diagram of the organization, it can be seen that:

(1) The coordinates of O _ZA , A ₀ and Z ₀ are known.

(2) The distance between A _I and O _ZA is a constant S _A , and the distance between A _I and Z _I is a constant S _Z .

(3) A _Ⅰ joint is coaxially connected, that is, ∠α and ∠β are fixed.

First calculate the elongation of cylinder A, apply the sine law in △A ₀ A ₁ O _ZA , as follows:

${<span\; class="notranslate">\; \&angle;</span>\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; sin</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{{<span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span>}{{<span\; class="notranslate">\; |</span>}_{\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}<span\; class="notranslate">\; |</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

$<span\; class="notranslate">\; \&angle;</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; \&angle;</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; \&angle;</span>\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

The value of ∠θ in the equipment mechanism can be obtained from formulas (3) and (4).

顺时针旋转∠θ可得向量

的方向，又S_A为向量

的长度，确定向量

即可得到点A_Ⅰ的坐标。具体计算如下：by vector

Rotate ∠θ clockwise to get the vector

direction, and S _A is the vector

length, determine the vector

The coordinates of point A _I can be obtained. The specific calculation is as follows:

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}\end{array}\right]\frac{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="0"\; label="o\; ZA\; A"\; filenames="HDA00003347509500051.png"\; state="\{\{state\}\}">o</figure-callout></span><figure-callout\; id="0"\; label="o\; ZA\; A"\; filenames="HDA00003347509500051.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{}_{}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}}{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="0"\; label="o\; ZA\; A"\; filenames="HDA00003347509500051.png"\; state="\{\{state\}\}">o</figure-callout></span><figure-callout\; id="0"\; label="o\; ZA\; A"\; filenames="HDA00003347509500051.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{}_{}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}}<span\; class="notranslate">\; +</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Similarly, the coordinates of Z _Ⅰ are calculated as follows:

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\left[\begin{array}{cc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}\\ \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&beta;</span>}\end{array}\right]\frac{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; ZA</span>}}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; Z</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; =</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

The coordinates of joint points A _Ⅰ and Z _Ⅰ of the equipment mechanism are calculated from formulas (5), (6), (7) and (8).

Based on the symmetry of the device, the coordinates of the joint points on the other side of the device are similarly calculated. So far, the coordinates of all relevant nodes of the ACB FET equipment have been solved, and the inverse solution of the mechanism has been completed. The elongation of the working cylinder can be calculated from the difference between the distance from the joint point to the hinge end of the working cylinder and the length of the working cylinder at zero position.

3. Drive equipment

Input the calculated elongation of each actuator of the ACB FET series horizontal stretching machine into the control panel of the ACB FET stretching machine, drive the equipment to move, move the clamp to the specified position, and check the position of the clamp to determine and theoretical design The location matches.

Step 3: Measure and calculate

1. Distance measurement

After checking that the positions of the clamp and the mold are correct, measure the distance between the feature points of the clamp and the feature points of the mold, as shown in Figure 7. According to the X direction, the mold and clamp are divided into the left side, which is the negative X direction side, and the right side, which is the positive X direction side. Measure the distance from the two feature points P _L1 and P _L2 of the left clamp to the feature point T _L on the left end of the mold and the distance from the two feature points P _R1 and P _R2 of the right clamp to the feature point T on the right end of the mold _R and will record the measured distance.

2. Geometric calculation

As shown in Figure 8, the coordinates of the mold feature points are calculated according to the known coordinates of the clamp feature points and the measured distance, and the calculation method is as follows:

Feature points on the left side of the mold $T_L{({x_T}_L,{{\mathrm{the\; y}}_T}_L,{Z_T}_L)}^T:$

by $P_{L1}{({x_P}_{L1},{{\mathrm{the\; y}}_P}_{L1},{Z_P}_{L1})}^T$ The equation of a circle whose center is L and _L1 is radius is

${<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

by $P_{L2}{({x_P}_{L2},{{\mathrm{the\; y}}_P}_{L2},{Z_P}_{L2})}^T$ The equation of a circle whose center is L and _L1 is radius is

Since the points P _L1 , P _L2 , and T _L are in the same height plane, that is:

${{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; =</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

的两个解，取

较大的解为真解，即模具左侧特征点的解。Simultaneous equations, get about the point

The two solutions of , take

The larger solution is the true solution, that is, the solution of the feature point on the left side of the mold.

The solution to the feature points on the right side of the mold is understood in the same way $T_R{({x_T}_R,{{\mathrm{the\; y}}_T}_R,{Z_T}_R)}^T.$

Step 4: Die positioning calculation

Obtain the mold feature point coordinates from the previous step $T_L{({x_T}_L,{{\mathrm{the\; y}}_T}_L,{Z_T}_L)}^T$ and $T_R{({x_T}_R,{{\mathrm{the\; y}}_T}_R,{Z_T}_R)}^T,$ By comparing with the theoretical value of the mold feature points, the transformation relationship between the theoretical mold position and the actual mold position is calculated, as shown in Figure 9. The mold position transformation in the plane is realized by a translation and a rotation transformation, and the transformation parameters are calculated as follows:

The coordinates of the midpoint T _O of the line connecting T _L and T _R :

${<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}$

与

连线中点

的坐标：

and

midpoint

coordinate of:

${<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; ,</span>{{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}$

translation vector

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="0"\; label="o"\; filenames="HDA00003347509500051.png"\; state="\{\{state\}\}">o</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

Rotation angle θ:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; cos</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; .</span>}\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}}}{<span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; |</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; |</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

axis of rotation vector

$\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; =</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; \&times;</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 16</span>}<span\; class="notranslate">\; )</span>$

Step 5: Correct the NC code for drawing

From the transformation parameters calculated in the previous step, the theoretical mold is transformed to the actual mold placement position, and the new mold position is used as a benchmark, and the process parameters are applied to generate the equipment CNC code that matches the actual mold position. Input the CNC code of the drawing equipment into the ACB FET horizontal drawing machine, run the drawing machine with no load, and check whether the movement of the equipment is consistent with the designed process parameters. After the check is correct, carry out skin pulling.

Claims (3)

1. mould localization method based on characteristic distance, its step is as follows:

Step 1: mould is initially put

Initially putting of skin part stretch forming mold is that actual mould is placed in the coordinate system of pull-shaped equipment, is the preparation of carrying out mould location survey and Stretch Forming Process;

Die layout together is placed in the coordinate system of pull-shaped equipment with cushion block on the standard cushion block, and the standard cushion block is the homemade standard component of factory, distinguishes by the mold weight that height and cushion block can hold; Mould is initially put at first according to the pull-shaped die boundary dimensions of covering and quality, choice criteria cushion block; Then put cushion block and mould according to the factory technics rules, measure cushion block end face levelness, guarantee cushion block placement level, record cushion block height H and mold feature point are apart from mould bottom surface height h;

Step 2: sports equipment

Sports equipment is that the equipment clamp with ACB FET series transverse stretching machine moves to assigned address, and it is in the same level that clamp characteristic point and mold feature point is in, and is convenient to range measurement;

(1) determines coordinate

Determine the coordinate position at clamp characteristic point place when measuring, by the height of cushion block and the mold feature point distance apart from the mould bottom surface, the height of determining mold feature point place horizontal plane is the Z coordinate; By appearance and size and the theoretical locus of putting of mould, determine that the position of clamp characteristic point on X-axis is the X coordinate; According to the position of clamp characteristic point on clamp, can obtain the Y coordinate of clamp characteristic point;

(2) equipment is counter separates

The anti-solution of motion of ACB FET series transverse stretching machine is the coordinate position by the clamp characteristic point, solves the length of each pressurized strut on the parallel institution according to the mechanical feature of pull-shaped equipment, i.e. the kinematic parameter of equipment; The machine drawing of ACBFET series digital control horizontal is used for that the aircraft skin part is horizontal to pull into shape; This equipment is the left-right symmetry structure, a friction clamp mouth of every side clamp, and two horizontal pressurized struts, two vertical pressurized struts form two pairs of four bar parallel institutions; The locus of clamp and attitude are determined jointly by the elongation of four pressurized struts; Position when measuring, in order to simplify the anti-computational process of separating of motion, set the clamp axis parallel with Y-axis, therefore only need to calculate the position of clamp in the ZX plane, namely only need to calculate the elongation of Z pressurized strut and A pressurized strut;

(3) driving arrangement

The elongation of each pressurized strut of stretching machine, stretching former that the anti-solution of ACB FET series transverse stretching machine is obtained, the interface driving arrangement motion of input digital control horizontal machine drawing control system makes clamp move to assigned address, is used for carrying out range measurement;

Step 3: measure and calculate

Measuring process is to measure each characteristic point of clamp to the distance of each characteristic point of mould, then calculates through how much, obtains the coordinate of characteristic point;

(1) range measurement

In the left side, two clamps in right side, two characteristic points of mark respectively, be designated as P _L1, P _L2And P _R1, P _R2; Two characteristic points of mark are designated as T on mould _LAnd T _R; Measure respectively P _L1, P _L2To T _LDistance and P _R1, P _R2; To T _RDistance;

(2) calculate for how much

After the motion of step 2 driving arrangement, characteristic point and mold feature point is in the horizontal plane of sustained height on the clamp, so the mould location Calculation can be utilized the method for solving of plane geometry, the coordinate of calculating mold feature point;

Take in the left side as example, mold feature point T _LConcrete coordinate can be by with P _L1Be the center of circle, L _L1For the circle of radius and with P _L2Be the center of circle, L _L2Determine for the intersection point of the circle of radius, in like manner can determine right side mold feature point T _RConcrete coordinate;

Step 4: mould location Calculation

The concrete coordinate of the mold feature point that calculates by measurement compares calculating with mold feature point theoretical coordinate, draws translation vector and rotational angle in the die top cushion block holding plane;

Step 5: revise numerical control code and carry out pull-shaped

The transformation parameter that is calculated by step 4, theoretical mould is transformed to the actual mould putting position, take new die location as benchmark, the technique for applying parameter generates the equipment numerical control code that conforms to the actual mould position, with the horizontal stretching machine, stretching former of pull-shaped equipment numerical control code input ACB FET, stretching machine, stretching former is carried out no-load running, whether the checkout facility motion conforms to designed technological parameter, check errorless after, carry out covering pull-shaped;

By above-mentioned five steps, realize the quick location of pull-shaped die space position, revise the method for pull-shaped track by the mould physical location, allow the stretch forming process of skin part tally with the actual situation, make and be able to little on the impact of part forming precision because of the die layout position deviation, reduce the use of positioning tool, guaranteed the precision that the aircraft skin part is produced.

2. a kind of mould localization method based on characteristic distance according to claim 1, it is characterized in that: the method for finding the solution the equipment moving parameter at the coordinate that passes through the clamp characteristic point described in the step 2, utilize the accurate control ability of equipment mechanism characteristics and numerical controlled stretch forming equipment, realized by clamp trace generator numerical control code Stretch Forming Process accurately being controlled.

3. a kind of mould localization method based on characteristic distance according to claim 1, it is characterized in that: distance is determined the method for mold feature point position between the measurement characteristic point described in the step 3, by simple measurement and how much calculating, realize the die space location positioning, the method is simple and practical, is convenient to implement.

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