Optimizing method for five-axis numerical control machining singular region cutter location point

Abstract

The invention discloses an optimizing method for a five-axis numerical control machining singular region cutter location point.A cutter shaft destination vector in a neighbourhood of the cutter shaft destination vector is optimized to obtain the optimized cutter shaft vector, so that the included angle theta between the projects, on a plane with the polar axis as a normal vector, of a cutter shaft start vector and the cutter shaft destination vector is the smallest to reduce the motion quantity of a first rotating shaft of a machine tool, and the cutter track in a singular region is optimized.By the adoption of the optimizing method, reliability of machining accuracy can be improved, program calculation is simple, the machining time is greatly shortened, and machining efficiency is improved.

Description

technical field

[0001] The invention relates to the field of numerical control machining, in particular to a method for optimizing tool positions in singular areas of five-axis numerical control machining. Background technique

[0002] Five-axis machining adds two rotation axes on the basis of three-axis machining, which are the active rotation axis and the driven rotation axis. Generally, the active axis is called the first rotation axis, and the driven axis is the second rotation axis. As a result, the processing method is more flexible, the material removal rate is higher, the processing time is shorter, and more complex parts can be processed. Therefore, five-axis machining has been widely used in aviation, aerospace, automobile, shipbuilding and other industrial fields. But the motion of the rotary axis also complicates tool attitude control, introducing many issues unique to five-axis machining. The singular point problem is one of the important ones.

[0003] In fi...

Examples

Embodiment 1

[0050] First, in order to facilitate the understanding of the problems in the singular region, a geometric model of the singular region is established, such as figure 1 shown.

[0051] figure 1Among them, V1 represents the start vector of the tool axis, V2 represents the end vector of the tool axis, θ represents the angle between the start vector of the tool axis and the end vector of the tool axis on the projection plane, O represents the origin, Vp represents the polar axis, and Vp As the axis, take the V1 and V2 vectors as the generatrices to make a cone-shaped space, and the projection to the plane is the circle A.

[0052] When the angle between V1, V2 and the polar axis Vp is small, even if the angle between V1, V2 is small, the angle θ of their projections on the plane with the polar axis Vp as the normal vector may be very large, This is the fundamental reason why the spindle of the machine tool still needs to swing a lot even though the swing angle on the same sur...

Embodiment 2

[0059] The difference with embodiment 1 is only: when the polar axis is outside the neighborhood of the tool axis end vector, establish as figure 2 The mathematical model for tool path optimization is shown.

[0060] figure 2 , to be optimized vector V 2 is the center line, the origin O is the apex, and the tolerance Δα is the half-vertex angle to form a conical space. All the generatrices of the conical space and the vector V 2 The included angles are Δα. Through the polar axis Vp, two planes are tangent to the conical surface, and the tangent vectors formed are respectively used by the vector V - and V + express.

[0061] vector V - and V + The angles projected on the plane where the polar axis Vp is the normal vector are Δγ and -Δγ respectively. After the vector V to be optimized 2 with V - and V + Two planes p' and p" are made respectively, and the vector of the previous tool axis is used as the optimization target vector of the current tool axis, and the opti...

Embodiment 3

[0068] Embodiment 1 and embodiment 2 are the optimization methods that the tool axis ends up in the vector under two different situations, especially the optimization method in embodiment 2, because the mathematical expression is used to find V - and V + Relatively complex, in order to better realize the present invention, the applicant transformed it into a mathematical expression for further disclosure.

[0069] Known: optimize the target vector v 1 =(i 1 j 1 k 1 ), the vector to be optimized v=(ijk), the polar axis vector v p =(i p j p k p ), tolerance Δα.

[0070] Seek: Optimize the tool axis vector v y =(i'j'k'), so that the angle between the tool axis vector after optimization and the vector to be optimized (v p v)y v 1 v p ) | min.

[0071] Through the above analysis, the mathematical model of tool path optimization can be simplified into a ternary quadratic equation system:

[0072] ...

technical field

[0001] The invention relates to the field of numerical control machining, in particular to a method for optimizing tool positions in singular areas of five-axis numerical control machining. Background technique

[0002] Five-axis machining adds two rotation axes on the basis of three-axis machining, which are the active rotation axis and the driven rotation axis. Generally, the active axis is called the first rotation axis, and the driven axis is the second rotation axis. As a result, the processing method is more flexible, the material removal rate is higher, the processing time is shorter, and more complex parts can be processed. Therefore, five-axis machining has been widely used in aviation, aerospace, automobile, shipbuilding and other industrial fields. But the motion of the rotary axis also complicates tool attitude control, introducing many issues unique to five-axis machining. The singular point problem is one of the important ones.

[0003] In fi...

Examples

Embodiment 1

[0050] First, in order to facilitate the understanding of the problems in the singular region, a geometric model of the singular region is established, such as figure 1 shown.

[0051] figure 1Among them, V1 represents the start vector of the tool axis, V2 represents the end vector of the tool axis, θ represents the angle between the start vector of the tool axis and the end vector of the tool axis on the projection plane, O represents the origin, Vp represents the polar axis, and Vp As the axis, take the V1 and V2 vectors as the generatrices to make a cone-shaped space, and the projection to the plane is the circle A.

[0052] When the angle between V1, V2 and the polar axis Vp is small, even if the angle between V1, V2 is small, the angle θ of their projections on the plane with the polar axis Vp as the normal vector may be very large, This is the fundamental reason why the spindle of the machine tool still needs to swing a lot even though the swing angle on the same sur...

Embodiment 2

[0059] The difference with embodiment 1 is only: when the polar axis is outside the neighborhood of the tool axis end vector, establish as figure 2 The mathematical model for tool path optimization is shown.

[0060] figure 2 , to be optimized vector V 2 is the center line, the origin O is the apex, and the tolerance Δα is the half-vertex angle to form a conical space. All the generatrices of the conical space and the vector V 2 The included angles are Δα. Through the polar axis Vp, two planes are tangent to the conical surface, and the tangent vectors formed are respectively used by the vector V - and V + express.

[0061] vector V - and V + The angles projected on the plane where the polar axis Vp is the normal vector are Δγ and -Δγ respectively. After the vector V to be optimized 2 with V - and V + Two planes p' and p" are made respectively, and the vector of the previous tool axis is used as the optimization target vector of the current tool axis, and the opti...

Embodiment 3

[0068] Embodiment 1 and embodiment 2 are the optimization methods that the tool axis ends up in the vector under two different situations, especially the optimization method in embodiment 2, because the mathematical expression is used to find V - and V + Relatively complex, in order to better realize the present invention, the applicant transformed it into a mathematical expression for further disclosure.

[0069] Known: optimize the target vector v 1 =(i 1 j 1 k 1 ), the vector to be optimized v=(ijk), the polar axis vector v p =(i p j p k p ), tolerance Δα.

[0070] Seek: Optimize the tool axis vector v y =(i'j'k'), so that the angle between the tool axis vector after optimization and the vector to be optimized (v p v)y v 1 v p ) | min.

[0071] Through the above analysis, the mathematical model of tool path optimization can be simplified into a ternary quadratic equation system:

[0072] ...

Images