DRIVE SYSTEM AND ASSESSMENT THEREOF

Abstract

The invention relates to a method for the assessment of a drive system (22) of a machine tool (21) or of a production machine (21), the drive system (22) having an axis (23, 24, 25), wherein a load of the drive system (22) is simulated, a drive profile (20) being used for simulation, actual values of the drive system (22) being simulated, the simulated actual values (40) being correlated with comparative values (41). The drive system (22) has at least one axis (23, 24, 25), a simulated load of the drive system (22) being correlated with at least one comparative value (41) on the basis of a drive profile (20).

Claims

1.-17. (canceled)

18. A method for the assessment of a drive system for dimensioning of a machine tool or of a robot, said method comprising: simulating actual values of the drive system with a drive profile; correlating the simulated actual values with comparative values; simulating a load of at least three axes of the drive system; and determining from the simulation of the load which of the at least three axes and which dynamic variable has a limiting effect on dynamics as a part program is executed.

19. The method of claim 18, wherein the drive profile is based on the part program.

20. The method of claim 18, further comprising changing the drive profile in response to the simulated actual values.

21. The method of claim 18, wherein a load on the at least one of the axes is used to dimension the machine tool or robot.

22. The method of claim 18, wherein the simulated actual values are average values obtained during a single cycle of the machine tool or robot; and further comprising changing dimensioning of the machine tool or robot in dependence on the average value.

23. The method of claim 18, wherein machine parameters are used for simulating actual values of the drive system.

24. The method of claim 18, wherein the comparative values comprise values selected from the group consisting of a maximum torque, a maximum rotational speed, a maximum power, a maximum current, a maximum speed, a maximum force, and a motor characteristic curve.

25. The method of claim 18, further comprising: simulating a single operating cycle of the machine tool or robot; and thermally evaluating characteristic properties of the single operating cycle.

26. The method of claim 18, further comprising establishing a torque-rotational speed diagram for a machine tool or robot having five or more interpolated axes.

27. The method of claim 18, further comprising establishing a histogram of dynamic limits.

28. The method of claim 18, further comprising determining a value related to productivity of the machine tool or robot, or a value related to manufacturing quality of the machine tool or robot.

29. The method of claim 18, further comprising: determining an axis or a variable limiting of the at least three axes that limits performance of the machine tool or robot; and optimizing drive dimensioning, motor dimensioning, kinematic parameters or a clamping situation.

30. A drive system, in particular of a machine tool or a production machine, said drive system comprising at least one axis, wherein a simulated load of the drive system is correlated with at least one comparative value on the basis of a drive profile, wherein the drive system is configured to execute a method as set forth in claim 18.

31. The drive system of claim 30, further comprising a simulation computer linked by data connection via the Internet to the machine tool or production machine.

32. The drive system of claim 30, further comprising: a plurality of simulation computers linked by data connection via the Internet to the machine tool or production machine and generating simulation data; and a computer operably connected to the plurality of simulation computers to link up the simulation data of the plurality of simulation computers.

33. A drive system, in particular of a machine tool or a production machine, comprising at least three axes, and a simulation computer configured to simulate actual values of the drive system with a drive profile; correlate the simulated actual values with comparative values; simulate a load of the at least three axes of the drive system, and determining from the simulation of the load which of the at least three axes and which dynamic variable has a limiting effect on dynamics as a part program is executed.

34. The drive system of claim 33, wherein the simulation computer is linked by data connection via the internet to the machine tool or production machine.

35. The drive system of claim 33, comprising: a plurality of simulation computers linked by data connection via the Internet to the machine tool or production machine and generating simulation data; and a computer operably connected to the plurality of simulation computers to link the simulation data from the plurality of simulation computers.

Description

[0078] The invention is explained in more detail below with reference to exemplary embodiments. In the drawings:

[0079] FIG. 1 shows a load cycle of a Z-axis of a machine;

[0080] FIG. 2 shows a load cycle of a Z-axis of a machine;

[0081] FIG. 3 shows a jerk of the axes X, Y and Z of a machine;

[0082] FIG. 4 shows a 3D representation of a contour traveled;

[0083] FIG. 5 shows a drive profile;

[0084] FIG. 6 shows a machine; and

[0085] FIG. 7 shows simulation steps.

[0086] FIG. 1 shows by way of example a load cycle 3 of a z-axis during the machining of an impeller wheel, wherein the load cycle relates to an accelerating torque on the z-axis. The rotational speed n_Mot of a motor in 1/min is plotted on an abscissa. An accelerating torque M in Nm is plotted on an ordinate 2. At no point in the cycle are the characteristic curves and limits of the motor and power section violated. The limit curves for torque, power and rotational speed lie outside the range shown. The point 8 for effective torque represents the average point in the cycle and is relevant for the thermal evaluation of the cycle. An upper S1-100K line 6 and a lower S1-100K line 7 are shown. Because the point 8 lies directly on the upper S1-100K line 6, the dimensioning is thermally critical and the use of a different motor should be considered. An upper S3-25% line 4 and a lower S3-25% line 5 are also shown, which are not violated.

[0087] Continuing on from FIG. 1, FIG. 2 shows a further curve 3 showing the load cycle of a Y-axis associated with the X-axis of FIG. 1 during the machining of the impeller wheel. At no point in the cycle are the characteristic curves and limits of the motor and power section violated. The limit curves for torque, power and rotational speed lie outside the range shown. The cycle is also non-critical thermally because the point 8 lies inside the range specified by the characteristic curves 4, 5, 6 and 7.

[0088] FIG. 3 shows as a percentage the frequency of occurrence of a jerk along three axes: X 11, Y 12 and Z 13. The magnitude of the jerk is plotted on the abscissa 9 in m/s.sup.3. Plotted on the ordinate 10 is in each case the percentage frequency P of occurrence of the jerk as a function of its strength. On the basis of a simulation, axes and their dynamic variables (jerk, acceleration or speed) can be determined. Using the simulation it is then possible to determine which axis and which dynamic variable (jerk, acceleration or speed) is having a limiting effect on dynamics during the sequence of the part program. A suitable representation can be produced e.g. as a histogram, as shown with an example in FIG. 3. According to the representation, columns 14 show that in many cases the jerk of the Z-axis is having a limiting effect. Different clamping situations, for example, can also be compared very easily with this method. In 5-axis machining, the Cartesian axes must additionally apply the compensating motions. Invisible path dynamics can cause highly dynamic compensating motions because of kinematics. The relationship between limits and machining time is non-trivial and difficult to evaluate. The representations described above can help in this regard: [0089] Torque-rotational speed diagram for e.g. five axes (not shown) [0090] Histogram of the dynamic limits e.g. over five axes (not shown).

[0091] FIG. 4 shows a 3D representation 15 of a contour traveled in a workpiece coordinate system. It is also possible for example to overlay colors in a three-dimensional representation of the contour traveled in the workpiece coordinate to represent which axis is having a limiting effect at the point indicated. A first green curve 16 represents, by way of example, the contour traveled in the workpiece coordinate system, wherein points or surfaces 17 where a c-axis is having a limiting effect are marked in red. Here the c-axis represents an axis of rotation of a machine tool.

[0092] FIG. 5 shows a drive profile 20. A time t is plotted on an abscissa 18 and a route x is plotted on an ordinate 19.

[0093] FIG. 6 shows a machine 21, which has at least part of the drive system 22. The machine 21 is a machine tool, for example. The drive 22 has a first axis 23, a second axis 24 and a third axis 25. A motor 26, 27 and 28 is assigned to each of the axes 23, 24 and 25 for the purpose of driving. A current converter 29, 30 and 31 is assigned to each of the motors 26, 27 and 28 in order to supply each motor 26, 27 and 28 with electrical energy. The drive system 22 has a large number of simulation computers 32, 33 and 34, wherein one computer 35 is provided in order to link up simulation data of the large number of simulation computers 32, 33, 34. After the simulation and the automatic assessment, in particular the identification of overloads, the drive system and/or also a part program can be modified automatically (e.g. with more powerful drives) such that the overall performance capability of the drive system increases.

[0094] FIG. 7 shows simulation steps, wherein in accordance with the simulation 44 simulated actual values 40 are correlated with comparative values 41. By way of example, data from a part program 42a, machine parameters 43 and/or a drive profile 20a are used for the simulation. After the assessment, the part program 42b can be modified automatically so that after a further simulation the limit values are exceeded at least to a lesser extent. Modifying the part program 42b also results in another drive profile 20b.