METHOD FOR CONTROLLING A MANIPULATOR FOR CARRYING OUT A WORKING PROCESS

Abstract

A method for controlling at least one manipulator for carrying out a working process which is controlled by a process controller comprises the steps of: a) providing one or more working points to be approached by the manipulator, b) approaching a working point A.sub.n by the manipulator, c) checking whether a subsequent working point A.sub.n+1 is present and, if a subsequent working point A.sub.n+1 is present, d) retrieving one or more data sets for the subsequent working point A.sub.n+1 while the working process is being carried out at the working point A.sub.n.

Claims

1. A method for controlling at least one manipulator for carrying out a working process, which is controlled by a process controller, wherein the method comprises following steps: a) providing one or more working points, which have to be approached by the manipulator; b) approaching a working point A.sub.n by the manipulator; c) checking, whether a subsequent working point A.sub.n+1 is present; and d) if a subsequent working point A.sub.n+1 is present, retrieving one or more data sets for the subsequent working point A.sub.n+1, while the working process is being earned out at the working point A.sub.n.

2. The method of claim 1, wherein the one or more data sets are retrieved at step d) by the manipulator controller.

3. The method of claim 1, wherein the one or more data sets are retrieved at step d) from the process controller, which controls the working process.

4. The method of claim 1, wherein the checking at step c) is carried out, while the manipulator is at working point A.sub.n.

5. The method of claim 1, further comprising the following step: applying, by the manipulator controller, of the retrieved data sets from step d) on a path planning for approaching the subsequent working point A.sub.n+1.

6. The method of claim 1, further comprising the steps of: sending actual data of working point A.sub.n and/or actual data of the manipulator at working point A.sub.n by the manipulator controller to the process controller, which controls the working process, while the manipulator is at working point A.sub.n, and applying the actual data sent to the process controller.

7. The method of claim 6, wherein the actual data at least comprise: position, arrangement, status, location of the one or more manipulators, and end effector position.

8. The method of claim 1, further comprising the following step before step b): storing, for each working point, one or more data sets for the working process in the process controller, which controls the working process.

9. The method of claim 1, further comprising the steps of: implementing the process controller in a host PC; and controlling the manipulator controller through the host PC.

10. The method of claim 1, wherein the working process is selected from the group consisting of joining processes and riveting processes.

11. A manipulator system, comprising: at least one manipulator; a process controller; and a manipulator controller, wherein the system is configured to: a) provide one or more working points, which have to be approached by the at least one manipulator; b) approach a working point A.sub.n by the manipulator; c) check whether a subsequent working point A.sub.n+1 is present; and d) if a subsequent working point A.sub.n+1 is present, retrieve one or more data sets for the subsequent working point A.sub.n+1, while the working process is being carried out at the working point A.sub.n.

12. The method of claim 10, wherein the working process is selected from the group consisting of clinching and pass-through joining.

13. The method of claim 10, wherein the working process is selected from the group consisting of resistance point welding and pass-through riveting.

Description

4. EXEMPLARY EMBODIMENT

[0023] The present invention is explained in the following by means of annexed figures. In particular:

[0024] FIG. 1 shows a schematic flow chart for an inventive method, and

[0025] FIG. 2 schematically shows a manipulator system for carrying out the method.

[0026] As shown in FIG. 1, in a first step S1, various working points are provided, which have to be approached by a manipulator. These points are preferably provided to a process controller, which is provided on a host PC. The process controller is communicating with the manipulator controller, which usually is a proprietary system of the manipulator manufacturer, which is separated from the process controller. The working points are certain spatial coordinates, for example, at which the manipulator has to carry out certain working processes, such as the application of a welding point. At step S2, the manipulator approaches a working point A.sub.n. To this end, the manipulator controller has received from the process controller the spatial coordinates of the working points, for example, and has calculated a certain path planning, which is autonomously followed by the manipulator. At step S3, the manipulator controller checks, whether, after working point A.sub.n, a subsequent working point A.sub.n+1 is present. If not, the working process is terminated. The checking may be performed, for example, while the manipulator approaches working point A.sub.n, i.e. on its way towards this working point A.sub.n. However, checking may also be performed when the manipulator has ended its approaching, i.e. when it has reached working point A.sub.n.

[0027] If, by this checking, it is determined that a subsequent working point A.sub.n+1 is present, then, at step S4, the manipulator controller retrieves data sets for the subsequent working process from process controller, in particular prior to manipulator leaving working point A.sub.n. The retrieval of data sets for the subsequent working process A.sub.n+1 thus occurs while working process at working point A.sub.n is still being carried out.

[0028] FIG. 2 schematically shows a manipulator system 1, which comprises a manipulator 10, a manipulator controller 30 and a process controller 40. The manipulator 10 preferably a multi-axis articulated arm robot, which comprises a plurality of members 11, 12, which are connected to each other by means of rotary joints 13, 14 and 15. The manipulates 10 is attached to a pedestal 16. The manipulates 10 is provided at as hand flange with an effector 20, which, in the example shown, is a welding clamp for point welding. The manipulates controller 30 is housed inside its own housing and runs on its micro-PC or similar, for example. The process controller 40 also runs on own PC and sends commands to the manipulator controller 30, in order to control the working process of the manipulator 10 known the manipulator controller 30 implements commands of the process controller 40. When the process controller 40 instructs, for example, that the manipulator 10 (or the effector 20) has to approach a certain spatial coordinate, then the manipulate controller 30 calculates the path planning, i.e. the motion path traveled by manipulator, in order to reach the predetermined spatial coordinate.

[0029] In FIG. 2 a series of crosses is shown, which indicate different working points, which the manipulator 10 or the effector 20 has to approach. The curve should indicate the planned path, which the manipulator controller 30 has calculated, in order for the manipulator 10 to approach all predetermined working points, possibly without conspicuous deviations. The working points themselves are predetermined or set by the process controller. At each working point, the effector 20 has to be oriented in a certain orientation and afterwards it has to apply a welding point by using a predetermined welding power (current ramp angle, welding duration, optional cooling phases, etc.). These process data are also provided to the manipulator controller 30 by the process controller 40. Depending on the working process, it may occur, that certain parameters vary, such as the electrode cap length, which is regularly detected by the manipulator controller 30, in that both electrode caps are brought together and the current rise is measured. The length variation may be calculated from these data.

[0030] In the example shown, the manipulator 10 or effector 20 is at a working point A.sub.n, i.e. the manipulator has completely reached the working point A.sub.n. In the position shown, a first welding point has to be applied. While the manipulator 10 performs the corresponding welding process, the manipulator controller 30 checks, whether a subsequent working point A.sub.n+1 is provided. If this is true, the manipulator controller 30 asks the process controller 40 to provide the required data sets (current ramp angle, welding time, optional cooling phases, etc.) for the subsequent working point A.sub.n+1. These data sets are then preferably considered by the manipulator controller 30 in the new calculation of the planned path for approaching the subsequent working point A.sub.n+1. The manipulator controller 30 also preferably transmits, while the manipulator 10 is working at working point A.sub.n, actual data regarding working point A.sub.n to the process controller 40. These actual data may refer, for example, to the actual welding force, the metal sheet thickness tolerance (the welding clamp determines, for example, at each point, the thickness of the sheet metal and calculates a tolerance based thereon) and other important parameters. These actual data may be used by the process controller 40, in order to adapt or optimize the subsequent working processes, for example.

REFERENCE LIST

[0031] S1 to S4 method steps [0032] 1 manipulator system [0033] 10 manipulator [0034] 11,12 members [0035] 13, 14, 15 joints [0036] 16 pedestal [0037] 20 effector [0038] 30 manipulator controller [0039] 40 process controller