JPH05204430A - Numerical control program preparing method - Google Patents

Abstract

PURPOSE:To attain a preparation by an interactive system without any trial and error or intuition by turning the knowledge of a force to a joint or a torque to a data base by analyzing the movement of a human body, and designing a program about a new movement by using dynamics, constraint, and inversion dynamics. CONSTITUTION:The knowledge of the force to the joint and the torque or the like is turned to the data base by analyzing the movement of the human body. Then, the program about the new movement desired by a programer is designed by using the knowledge. First of all, in the step of the dynamics, each element of a machine is discriminated, and the movement is taken out by the form of a dynamics equations. In the step of the constraint, a physical constraint including the relation of the mutual connection of each element and the range of the movement of each element is checked. In the step of the inversion dynamics, the movement and force checked by the constraint are calculated by using the dynamics equations, and the result of the movement and the force is displayed. That is, the new movement is calculated based only on the designated force and the dynamics equations, and then the constraint is checked, and the result of the movement is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control method for controlling a machine tool etc. by a numerical control program.

[Prior Art]

Numerical control technology in which a machine automatically performs machining in accordance with a numerical control program created in advance in a machine tool is widespread. In this numerical control technology, recently, there is a complex system called a computer aided (CAE) system or a computer integrated production (CIM) system that designs by a computer aided design (CAD) method and produces by a computer aided manufacturing (CAM) method. It is increasing.

Since these numerical control programs do not define matters relating to the processing method such as the processing direction, the magnitude of the force to be applied or the speed, which occupy an important position in the skill of a skilled human, the numerical control technology is used. It was not possible to perform so-called profession processing in which the direction of processing, the magnitude of the applied force, the processing speed, etc. are important, and it could only be used for relatively simple work.

Further, although it is desirable to create a numerical control program in a real-time manner by an easy-to-use interactive form, in the conventional numerical control program creation, contents confirmation by operation simulation and fine adjustment at a work site are required. As required, the programming work was complex and could not be done interactively alone.

In order to perform a masterly artistic work by numerical control, it is necessary to analyze human motion and create a control program based on the knowledge obtained as a result. Since the inaccurate knowledge obtained by is used, the obtained program is not necessarily rational. In addition, the dynamics used for analyzing and designing the motion tend to be inaccurate because it is based on kinematics using only position, velocity, and acceleration. Therefore, it has been difficult to create a new numerical control program only by a computer by the conventional method.

As a method for discussing the motion of an object, there is a method called dynamics for discussing the motion of an object in relation to force in addition to the kinematics using position / velocity and acceleration. If this method is used to create a numerical control program, complex movements can be programmed with a small number of operations. Further, according to the numerical control program creating method using the dynamics, another great advantage, that is, it is possible to create a new program which is impossible with the numerical control program creating method using kinematics.

As described above, by using the dynamic method of discussing the motion of an object in relation to the force, it is possible to program a complicated motion with a few operations. However, in the dynamic method, it is difficult to use dynamics for numerical control programming because data such as moment of inertia, center of gravity, friction and elasticity are difficult to measure.

In this method, the calculation amount O (f
(N)) because many are computational function of n ⁴ O (n ^4), calculated by the computer is not practical because it expensive.

On the other hand, there is also a kinetic method using a calculation in which the amount of calculation is a function O (n) of n, but this method is valid only when there is no rotation about the axis. Therefore, this method cannot be used when there is rotation around the axis.

As described above, the numerical control programming work up to now has been unavoidable by trial and error, and it has not been a real-time interactive response. Therefore, the present invention proposes a new dynamic numerical control program creation method capable of coping with complicated work.

[0011]

In the present invention, a new motion of a machine tool can be created by using the knowledge about the human motion obtained by dynamically analyzing the actual human motion. We propose a new numerical control programming creation method. That is, an object of the present invention is to provide a method of interactively creating a numerical control program using a computer without trial and error or intuition of a programmer.

[0012]

In order to solve the above-mentioned problems, in the numerical control program creating method using the dynamics of the present invention, the basic motion of a person is first analyzed.
Therefore, the data of the dynamic parameters including the force and torque generated at each joint of the human body are input to the database as knowledge about the basic movement of the human body.

Next, the programmer accesses the database and processes the obtained data, but the computer feeds back the result of the inverse dynamics to the programmer in the form of force in the form of motion with constrained conditions. Then, the motion is interactively designed by repeating this process until a satisfactory result is obtained.

The calculation amount of the numerical control program creating method using the dynamics is a function O (n) of n, which solves the problem that the calculation by the computer, which is present in the conventional method, is expensive. It is also possible to provide a numerical control program creation method that can be executed interactively without trial and error or the intuition of a programmer.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. A flow chart of the present invention is shown in FIG.
This flow chart is 1. Create a human body model 2. Input actual human movements 3. Analyze the input motion 4. Operation design 5. Application of dynamics 6. Application of constraints 7. Application of inverse dynamics 8. It consists of stages for displaying results.

In the first step, "creating a human body model", the human body is decomposed into parts which are the minimum units of motion, and the constraint conditions such as the characteristics peculiar to each part, the mutual relation, and the range of joint motion are considered. Based on this, create a human body model and enter it into a database on a computer.

In the second step of "inputting actual human motion", the motion to be analyzed is input in frame units of video images or frame units of film images. In this case, images taken simultaneously from a plurality of directions. Can be used for more specific analysis in the next step.

In the third step "Analysis of the input motion", the motion input in the second stage is calculated using inverse dynamics, and the center of gravity of each member, the force and torque acting on each joint, The center of gravity, the force acting on the center of gravity, and the torque are analyzed, and the data of the analysis result is input to the database.

Next, a case of creating a new motion numerical control program using the above analysis results will be described. In the fourth stage, "Motion Design," the programmer first selects a basic motion from the database. The data is represented by a control graph as shown in FIG. 2, for example. In this control graph, the horizontal axis represents time, and the vertical axis represents the force generated at each joint of the body with respect to the three axes x, y, and z. As a matter of course, the two forces generated in the same joint have the same magnitude and opposite directions. Also, complex movements are represented by several control graphs.

A numerical control program is created on the basis of this control graph. However, in order to correspond to the size and material of the workpiece, the operating range of the machine, etc., it is necessary to change the physical variables including the enlargement / reduction of the axis of the control graph. To do.

In the fifth stage, "Applying Dynamics",
The movement of each element of the machine tool is calculated based on the force and dynamic equations specified by the programmer. In that case,
Originally, each element has a mutual relation, but it is cut off from other elements in order to reduce the calculation amount, and the mutual relation between each element and the constraint condition regarding the range of motion are also temporarily ignored.

In order to calculate the movement of each element, in the present invention, Newton's equation is used to obtain the linear acceleration, and Euler's equation is used to obtain the angular acceleration. When the linear acceleration and the angular acceleration are obtained, These are integrated to obtain the velocity, and further integrated to obtain the position.

In the sixth step "Applying constraint conditions", two physical constraint conditions of the mutual connection relation of each element and the range of motion are checked for the calculation result of the motion of each element.
This processing starts from the basic element, and the position and arrangement direction of each of the lower elements are sequentially checked. Here, two checks are made as to whether or not the lower element is always connected to the upper element and whether or not the operation of each element exceeds a predetermined range.

As a result, when the lower element is not connected to the upper element, the lower element is moved in parallel so that the lower element is connected to the upper element, and the movement of each element is constant. If the value is out of the range, rotate it to adjust the movement of the element within the range.

In the seventh step "Applying inverse dynamics", the force that occurs at the connection point of each element is calculated using the Lagrange equation that expresses the relationship between force and motion.

When programming a new motion, if a satisfactory result is not obtained, the steps 5 to 7 are repeated to interactively design the new motion.

In the "display result" of the eighth step, a new movement in the middle of programming or after programming is displayed on the screen.

In the present invention, since the simple linear regression algorithm is used as shown in FIG. 1, the calculation amount is O (n) which is a function of n. Further, according to the present invention, the movement of the human body can be designed interactively using a computer without trial and error or the intuition of the designer.

[0029]

As described above, the dynamic numerical control programming method of the present invention comprises two processes: analysis of the basic movement of an actual human and creation of a new dynamic numerical control program. The basic human motion analysis proceeds in three steps: human body model creation, actual motion input, and input motion analysis, and dynamics numerical control program creation includes dynamics, constraints, and reverse dynamics. In the dynamics stage, the machine is divided into independent elements, and the movement of each element is calculated by using Newton's equation and Euler's equation and separated from the movements of other elements. At the constraint stage, the mutual relations of elements and the range of movement are checked. In the inverse dynamics stage, the force that produces the new motion modified by the constraints is calculated.
In that case, the total calculation amount is O (n).

[Brief description of drawings]

FIG. 1 is a flowchart of a numerical control programming method according to the present invention.

FIG. 2 is a control graph of an example of force acting on a joint.

Claims (2)

[Claims] 1. A method for creating a numerical control program for programming an operation based on human motion in a numerical control device, the method disassembling a human body into parts which are the minimum units of motion, and each of these parts is unique. Of the human body model based on constraints such as the characteristics of humans, mutual relations and the range of joint movements, and inputting it into the database; the step of inputting actual human movements; and the inverse dynamics of the input movements. Applying and calculating, calculating the center of gravity of each part, the force / torque acting on each joint, the center of gravity / force acting on the whole center of gravity / torque, and selecting the basic movement from the database and selecting its physical variables. The step of changing and cutting off each part of the body from the other part, and deriving the actual motion based on the specified force and dynamic equations only, ignoring the constraints on mutual coupling and range of joint motion. A step of calculating a motion, a step of checking and correcting a mutual constraint relation and a physical constraint condition of a range of motion of a joint in the calculation result, and a motion of the numerical controller on the screen using the calculated result. A method of creating a numerical control program, which comprises a step of displaying. 2. A method for creating a numerical control program for programming an operation based on human motion in a numerical control device, the method breaking down a human body into parts that are the minimum units of motion, and each of these parts is unique. Of the human body model based on constraints such as the nature, mutual relationship and range of joint movement, and input to the database; the step of inputting the actual human movement; and the inverse dynamics of the input movement. Applying and calculating, calculating the center of gravity of each part, the force / torque acting on each joint, the center of gravity / force acting on the whole center of gravity / torque, and selecting the basic movement from the database and selecting its physical variables. The step of changing and separating each part of the body from the other part, and deriving the actual motions based on the specified force and dynamic equations only, ignoring the constraints on the interconnection and the range of motion of the joints. A step of calculating a motion, a step of checking and correcting a mutual constraint relationship and a physical constraint condition of a range of motion of a joint for the calculation result, a motion calculated by the dynamics and a force calculated by an inverse dynamics, and And a step of synthesizing the center of gravity and displaying it on the screen.