Method and apparatus for monitoring an acceleration of an axis of a multi-axis kinematic system

Abstract

A method for monitoring acceleration of a number A of axes of a multi-axis kinematic system utilizes a sampling process with a first sampling interval, wherein a first acceleration limit value assigned to the first sampling interval and a second different acceleration limit value is determined for the acceleration, where a second time interval is assigned to the second acceleration limit value, a plurality of position values of the axis is determined by sampling with the first sampling interval, a current acceleration is calculated via the ascertained position values, and the calculated current acceleration is monitored via a first instance of monitoring utilizing the first acceleration limit value and the assigned first sampling interval and, simultaneously, via a second instance of monitoring utilizing the second acceleration limit value and the assigned second time interval, such that acceleration of an axis is monitored using at least two acceleration limit values simultaneously.

Claims

1. A method for monitoring an acceleration of a plurality A of axes of a multi-axis kinematic system utilizing at least one sampling process with a first sampling interval, the method comprising: a) determining a first acceleration limit value assigned to a first sampling interval and a second acceleration limit value, differing therefrom, for the acceleration of an axis of the plurality A of axes, wherein a second time interval is assigned to the second acceleration limit value; b) ascertaining a plurality N of position values of each of the plurality A of axes by sampling with the first sampling interval; c) calculating at least one current acceleration via the ascertained plurality N of position values; and d) monitoring the calculated at least one current acceleration via a first instance of monitoring utilizing the first acceleration limit value and the assigned first sampling interval and, at the same time, via a second instance of monitoring utilizing the second acceleration limit value and the assigned second time interval.

2. The method as claimed in claim 1, wherein said step d) comprises: comparing each calculated current acceleration with the first acceleration limit value utilized in a first instance of monitoring and with the second acceleration limit value limit value in a second instance of monitoring to ascertain whether the calculated current acceleration exceeds at least one of (i) the first limit value and (ii) the second acceleration limit value.

3. The method as claimed in claim 2, wherein an action is performed in step e) depending on whether the calculated current acceleration exceeds at least one of (i) the first acceleration limit value and (ii) the second acceleration limit value; and wherein the action comprises at least a stopping of the axis of the plurality A of axes.

4. The method as claimed in claim 1, wherein the plurality N of position values of each of the plurality A of axes, with N≥3, are ascertained in step b) by sampling with the first sampling interval; and wherein the ascertainment of the plurality N of position values is performed utilizing at least one position encoder.

5. The method as claimed in claim 2, wherein the plurality N of position values of each of the plurality A of axes, with N≥3, are ascertained in step b) by sampling with the first sampling interval; and wherein the ascertainment of the plurality N of position values is performed utilizing at least one position encoder.

6. The method as claimed in claim 3, wherein the plurality N of position values of each of the plurality A of axes, with N≥3, are ascertained in step b) by sampling with the first sampling interval; and wherein the ascertainment of the plurality N of position values is performed utilizing at least one position encoder.

7. The method as claimed in claim 1, wherein the second acceleration limit value in step a) is determined based on the first acceleration limit value and the first sampling interval.

8. The method as claimed in claim 4, wherein the current acceleration in step c) is calculated via the ascertained plurality N of position values, with N≥3; and wherein the current acceleration is calculated based on a calculated difference between first and second calculated speed values and at least one of (i) the first sampling interval and (ii) the second time interval.

9. The method as claimed in claim 7, wherein the current acceleration in step c) is calculated via the ascertained plurality N of position values, with N≥3; and wherein the current acceleration is calculated based on a calculated difference between first and second calculated speed values and at least one of (i) the first sampling interval and (ii) the second time interval.

10. The method as claimed in claim 7, wherein the first and the second speed values are each calculated from the plurality N the position values; and wherein position values of mutually adjacent sampling values of a sampling sequence are ascertained via sampling with the first sampling interval.

11. The method as claimed in claim 1, wherein the second time interval is formed as a second sampling interval, in which a plurality M of position values of each axis of the plurality A of axes are ascertained via sampling with the second sampling interval, with M≥3.

12. The method as claimed in claim 11, wherein the first acceleration limit value is less than the second acceleration limit value and the first sampling interval is greater than the second sampling interval.

13. The method as claimed in claim 1, further comprising: determining a plurality G of further acceleration limit values, in addition to the first and the second acceleration limit value, for monitoring the acceleration of the axis of the plurality A of axes, with G≥1; wherein each further acceleration limit value is assigned a further sampling interval and all acceleration limit values are formed differently from one another.

14. The method as claimed in claim 7, wherein the second time interval is selected as a filter time of a certain filter.

15. The method as claimed in claim 7, wherein the certain filter comprises a PT1 filter.

16. The method as claimed in claim 12, wherein the first acceleration limit value a.sub.Grenz is calculated in step a) in accordance with the following relationship: $a_{\mathrm{Grenz}}=\frac{1}{1-\left(\frac{1}{\left({\exp }^{\left(\frac{T_{\mathrm{Abtast}}}{T_{\mathrm{Filter}}}\right)}\right)}\right)}.Math.a_{\mathrm{Grenzfilter}}$ wherein a.sub.Grenzfilter is the second acceleration limit value, T.sub.Abtast is the first sampling interval and T.sub.Filter is the second time interval.

17. A non-transitory computer-readable medium encoded with a computer program which, when executed by a program-controlled device, causes monitoring of an acceleration of a plurality A of axes of a multi-axis kinematic system utilizing at least one sampling process with a first sampling interval, the computer program comprising: a) program code for determining a first acceleration limit value assigned to a first sampling interval and a second acceleration limit value, differing therefrom, for the acceleration of an axis of the plurality A of axes, a second time interval being assigned to the second acceleration limit value; b) program code for ascertaining a plurality N of position values of each of the plurality A of axes by sampling with the first sampling interval; c) program code for calculating at least one current acceleration via the ascertained plurality N of position values; and d) program code for monitoring the calculated at least one current acceleration via a first instance of monitoring utilizing the first acceleration limit value and the assigned first sampling interval and, at the same time, via a second instance of monitoring utilizing the second acceleration limit value and the assigned second time interval.

18. An apparatus for monitoring an acceleration of a plurality A of axes of a multi-axis kinematic system utilizing at least one sampling process with a first sampling interval, the apparatus comprising: a determiner unit for determining a first acceleration limit value assigned to the first sampling interval and a second acceleration limit value, differing therefrom, for acceleration of an axis of the plurality A of axes, a second time interval being assigned to the second acceleration limit value; an ascertainer for ascertaining a plurality N of position values of the axis of the plurality A of axes by sampling with the first sampling interval; a calculator for calculating at least a current acceleration via the ascertained plurality N of position values; and a monitor for monitoring the calculated current acceleration via a first instance of monitoring utilizing the first acceleration limit value and the assigned first sampling interval and, simultaneously, via a second instance of monitoring utilizing the second acceleration limit value and the assigned second time interval.

19. A machine having the apparatus as claimed in claim 18 and having the plurality A of axes of the multi-axis kinematic system, where A≥2; wherein the current acceleration of each axis of the plurality A of axes of the multi-axis kinematic system of the machine is monitored via the apparatus.

20. The machine having the apparatus as claimed in claim 19, wherein A≥4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous refinements and aspects of the invention are the subject matter of the dependent claims and of the exemplary embodiments, described below, of the invention. The invention is explained in more detail below on the basis of preferred embodiments with reference to the attached figures, in which:

(2) FIG. 1 shows a schematic flow chart of an exemplary embodiment of a method for monitoring an acceleration of a number A of axes of a multi-axis kinematic system; and

(3) FIG. 2 shows a schematic block diagram of an apparatus for monitoring an acceleration of a number A of axes of a multi-axis kinematic system.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

(4) In the figures, identical or functionally identical elements have been provided with the same reference signs, unless indicated otherwise.

(5) FIG. 1 shows a schematic flow chart of an exemplary embodiment of a method for monitoring an acceleration of a number A of axes 14 of a multi-axis kinematic system 15 (see FIG. 2) using at least one sampling process with a first sampling interval.

(6) In step S101, a first acceleration limit value assigned to the first sampling interval and a second acceleration limit value, differing therefrom, are determined for the acceleration of the axis 14. Here, a second time interval is assigned to the second acceleration limit value.

(7) In step S101, the second acceleration limit value is determined based on the first acceleration limit value and the first sampling interval.

(8) Further, the first acceleration limit value a.sub.Grenz is calculated in step S101 as a function of the second acceleration limit value a.sub.Grenzfilter, the first sampling interval T.sub.Abtast and the second time interval T.sub.Filter in accordance with the following relationship:

(9) $a_{\mathrm{Grenz}}=\frac{1}{1-\left(\frac{1}{\left({\exp }^{\left(\frac{T_{\mathrm{Abtast}}}{T_{\mathrm{Filter}}}\right)}\right)}\right)}.Math.a_{\mathrm{Grenzfilter}}$

(10) In step S102, a plurality N of position values of the axis 14 are ascertained by sampling with the first sampling interval. Here, the plurality N of position values of the axis 14 comprise N≥3 position values. Moreover, the plurality N of position values are ascertained using at least one position encoder.

(11) Next, at least one current acceleration is calculated in step S103 by means of the ascertained N position values. The plurality N of position values comprises N≥3 position values. In step S103, the current acceleration is calculated, in particular, based on a calculated difference between a first and a second calculated speed value and the first sampling interval and/or the second time interval. Here, the first and second speed value are calculated from the plurality N of position values. The position values of mutually adjacent sampling values of a sampling sequence are ascertained here by sampling with the first sampling interval.

(12) In step S104, the calculated current acceleration is monitored via a first instance of monitoring using the first acceleration limit value and the assigned first sampling interval and, at the same time, via a second instance of monitoring using the second acceleration limit value and the assigned second time interval.

(13) Additionally, in step S104, the calculated current acceleration is compared in each case with the first acceleration limit value used in the first instance of monitoring and with the second acceleration limit value used in the second instance of monitoring in order to ascertain whether the calculated current acceleration exceeds the first and/or the second acceleration limit value.

(14) Furthermore, an action is performed in a step not illustrated here, depending on whether the calculated current acceleration exceeds the first or the second acceleration limit value. Here, the action comprises at least the stopping of the axis 14.

(15) In particular, the second time interval is formed as a second sampling interval. Here, a plurality M of position values of the axis 14, with M≥3, are ascertained via sampling with a second sampling interval.

(16) Further, the first acceleration limit value is smaller than the second acceleration limit value. Moreover, the first sampling interval is greater than the second sampling interval.

(17) Likewise, a number G of further acceleration limit values are determined, in addition to the first and second acceleration limit value, for the purposes of monitoring the acceleration of the axis 14, with G≥1. Here, each further acceleration limit value is assigned a further sampling interval and all acceleration limit values have different embodiments from one another.

(18) Alternatively, the second time interval is selected as a filter time of a certain filter, where the certain filter comprises a PT1 filter, in particular.

(19) FIG. 2 shows a schematic flow chart of an apparatus 100 for monitoring an acceleration of a number A of axes 14 of the multi-axis kinematic system 15 using at least one sampling process with a first sampling interval.

(20) The apparatus 100 of FIG. 2 comprises a determination unit 10, an ascertainment unit 11, a calculation unit 12 and a monitoring unit 13.

(21) The determination unit 10 is configured to determine a first acceleration limit value assigned to the first sampling interval and a second acceleration limit value, differing therefrom, for the acceleration of the axis 14. Here, the second acceleration limit value is assigned to a second time interval.

(22) The ascertainment unit 11 is configured to ascertain a plurality N of position values of the axis 14 by sampling with the first sampling interval.

(23) Furthermore, the calculation unit 12 is configured to calculate at least one current acceleration via the ascertained N position values.

(24) The monitoring unit 13 is configured to monitor the calculated current acceleration via a first instance of monitoring using the first acceleration limit value and the assigned first sampling interval and, at the same time, via a second instance of monitoring using the second acceleration limit value and the assigned second time interval.

(25) Furthermore, FIG. 2 shows a machine, in particular a robot 16, having the apparatus 100 and having the plurality A of axes 14 of the multi-axis kinematic system 15. The number A of axes 14 is A≥2, in particular A≥4, where the number A of axes 14 shown in FIG. 2 is A≥2.

(26) The current acceleration of each axis 14 from the number A of axes 14 of the multi-axis kinematic system 15 of the robot 16 is monitored via the apparatus 100.

(27) Although the present invention has been described on the basis of exemplary embodiments, it is able to be modified in many ways.

(28) Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.