Assignment of sensors to machine parts

Abstract

A sensor assignment device includes a movement instruction generator for generating and submitting a movement instruction to a distinct one of a plurality of actuators to move a distinct one of a plurality of machine parts, a sensor data receiver for receiving sensor data acquired by a subset of a plurality of sensors, a degree of correlation determiner for determining sensor-specific degrees of correlation between the detected sensor data and the movement instruction, and a sensor assigner for assigning those sensors to the distinct machine part whose sensor-specific degrees of correlation exceed a predetermined threshold or a multiple-step fashion as refinement in case of insufficiently reliable map of affiliations between sensors and machine parts. The received sensor data is used to influence the movement instruction.

Claims

1. A sensor assignment device, comprising: a movement instruction generator configured to generate and submit a movement instruction to a distinct one of a plurality of actuators to move a distinct one of a plurality of machine parts; a sensor data receiver configured to receive sensor data based on movements of machine parts of three ceiling-mounted machines, acquired by a subset of a plurality of sensors, with each machine having a pushrod as a machine part; a degree of correlation determiner configured to determine sensor-specific degrees of correlation between the detected sensor data and the movement instruction; and a sensor assigner which, when obtaining a reliable map of affiliations between sensors and machine parts, assigns those sensors to the distinct one of the plurality of machine parts whose sensor-specific degrees of correlation exceed a predetermined threshold, and which, when obtaining an insufficiently reliable map of affiliations between sensors and machine parts, causes the sensor assignment device to repeat the steps of generating and submitting a movement instruction, receiving sensor data, and determining sensor-specific degrees of correlation; said sensor assignment device moving the machine parts using the distinct one of the plurality of actuators based on the sensor data.

2. The sensor assignment device of claim 1, wherein the degree of correlation determiner is configured to detect a temporal correlation between the submission of the movement instruction and the sensor data acquired by the subset of sensors.

3. The sensor assignment device of claim 1, wherein the movement instruction generator is configured to generate a movement instruction for the distinct one of the plurality of actuators to drive the distinct machine part such as to perform at least two different movements.

4. The sensor assignment device of claim 1, wherein the degree of correlation determiner is configured to detect a correlation between a requested movement pattern and an actual movement pattern actually performed by the distinct machine part and detected by the subset of sensors, said requested movement pattern being predetermined by one movement instruction or by a sequence of movement instructions.

5. The sensor assignment device of claim 1, wherein the degree of correlation determiner is configured to consider a type information when determining the degree of correlation, said type information defining a type of at least one of the sensors of the subset of sensors.

6. The sensor assignment device of claim 1, wherein the sensor assignment device is configured to broadcast a same movement instruction to all or to a subset of the plurality of actuators.

7. The sensor assignment device of claim 1, wherein the sensor assignment device is configured to broadcast movement instructions to different pluralities of actuators for narrowing down correlations between sensors and machine parts.

8. The sensor assignment device of claim 1, wherein the sensor assignment device includes a plausibility checker configured to check a plausibility of sensor assignments.

9. The sensor assignment device of claim 8, wherein the plausibility checker is configured to perform and evaluate a cross-correlation.

10. A method for assigning a sensor to a machine part moveable by an actuator, said method comprising: transmitting a movement instruction to a distinct one of a plurality of actuators to move a distinct one of a plurality of machine parts; acquiring sensor data based on movements of machine parts of three ceiling-mounted machines, by a subset of a plurality of sensors, with each machine having a pushrod as a machine part; determining sensor-specific degrees of correlation between the acquired sensor data and the movement instruction; assigning those sensors to the distinct machine part whose sensor-specific degrees of correlation exceed a predetermined threshold; and moving the machine parts by the distinct one of the plurality of actuators using the sensor data.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

(2) FIG. 1 a schematic illustration of an arrangement of a ceiling-mounted machinery and of a sensor assignment device;

(3) FIG. 2 a schematic diagram of an affiliation of machine parts to a machine, and of an affiliation of actuators and sensors to machine parts;

(4) FIG. 3 a schematic data flow from a sensor assignment device to an actuator controlling a movement of a machine part and from a sensor to the sensor assignment device, wherein the sensor acquires sensor data in dependence on the movement of the machine part; and

(5) FIG. 4 a schematic flow diagram of a method for assigning a sensor to a machine part moveable by an actuator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) Throughout all the figures, same or corresponding elements may generally be indicated by same reference numerals, These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments may be illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

(7) Turning now to the drawing, and in particular to FIG. 1, there is shown a schematic illustration of an arrangement of a ceiling-mounted machinery MA and of a controller CO for the machinery MA, the controller CO having a sensor assignment device SAD. The machinery MA comprises a set of machines M.sub.1, M.sub.2, M.sub.3. Each machine M.sub.1, M.sub.2, M.sub.3 comprises a set of machine parts MP.sub.j. In the example of FIG. 1, a first machine part MP.sub.11 of machine M.sub.1 serves as a fastening to a ceiling C. A second machine part M.sub.12 of this machine M.sub.1 is a rotating part. A third machine part M.sub.13 of this machine M.sub.1 is a four-bar mechanism. A fourth machine part M.sub.14 of this machine M.sub.1 is a telescopic or pushrod guide system, A first actuator A.sub.11 is for rotating the second machine part M.sub.12 relatively to the first machine part M.sub.11. The second actuator A.sub.12 is for lifting and lowering a bar of the four-bar mechanism. The third actuator A.sub.13 is for lifting and lowering a pushrod of the pushrod guide system. In the example of FIG. 1, the other two machines M.sub.2, M.sub.3 have corresponding components A.sub.21, A.sub.22, A.sub.23, A.sub.31, A.sub.32, A.sub.33. Each of the machines M.sub.1, M.sub.2, M.sub.3 has a first sensor S.sub.11, S.sub.21, S.sub.31 at its pushrod guide system MP.sub.14, MP.sub.24, MP.sub.34 and a second sensor S.sub.12, S.sub.22, S.sub.32 at a tip of its pushrod. In addition, the third machine M.sub.3 has a third sensor S.sub.33 at the pivot bearing.

(8) The sensor assignment device SAD comprises a sensor assigner SA, a movement instruction generator MIG, a sensor data receiver SDR, and a degree of correlation determiner DCD. The movement instruction generator MIG generates and submits movement instructions MI to distinct ones of actuators A.sub.k (k symbolizes a running index of the actuators). The movement instructions MI may be transmitted on wireless and/or on wireline transmission paths, The actuators A.sub.k receive the movement instructions M.sub.m and drive associated machine parts MP.sub.j (m symbolizes a running index of locations and/or of types of movements; j symbolizes a running index of machine parts). As a result, the machine parts MP.sub.j perform movements M.sub.m in accordance with the movement instructions MI. As a consequence of the movements M.sub.m sensors S.sub.i located at the machine parts MP.sub.j acquire sensor data SD comprising information on the movement M.sub.m performed by the associated machine part MP.sub.j. The acquired sensor data SD may be transmitted to the sensor assignment device SAD on wireless and/or on wireline transmission paths. The movement instructions MI and the received sensor data SD are fed to the degree of correlation determiner DCD. Starting from this information the degree of correlation determiner DCD calculates a correlation degree CD between movement instructions MI and the received sensor data SD. The correlation degree CD may describe a temporal and/or of a pattern-type correlation between said movement instructions MI and said received sensor data SD.

(9) The degree of correlation determiner DCD provides correlation information CI to the sensor assigner SA. The sensor assigner SA assigns those sensors S.sub.i to those machine parts MP.sub.j where the pair between a sensor S.sub.i and a machine part MP.sub.j has a correlation degree CD exceeding a predetermined threshold.

(10) Optionally, the sensor assignment device SAD may comprise a plausibility checker PC for checking degrees of correlation DC for plausibility. In a more particular embodiment, the plausibility checker PC may comprise a cross-correlation generator CCG for generating cross-correlations CC and a cross-correlation evaluator CCE for determining a plausibility P of cross-correlations CC.

(11) The set diagram of FIG. 2 shows an affiliation of machine parts MR.sub.41, MP.sub.42, MP.sub.43 to a machine M.sub.4 which may be added to and operated in the arrangement of FIG. 1. The set diagram shows an example of individual affiliations of actuators A.sub.k and sensors S.sub.i to machine parts MP.sub.j. Here, the actuator A.sub.4 drives (at least indirectly) as well machine part MP.sub.41 as well as machine part MP.sub.42. The actuator A.sub.2 drives (at least indirectly) as well machine part MP.sub.41 as well as machine part MP.sub.43. The sensor S.sub.4 is driven (at least indirectly) as well by machine part MP.sub.41 as well as by machine part MP.sub.42. The actuator S.sub.2 is driven (at least indirectly) as well by machine part MP.sub.42 as well as by machine part MP.sub.43.

(12) FIG. 3 shows schematically data flows MI, SD, Al between a sensor assignment device SAD to actuators A.sub.k controlling movements M.sub.m of machine parts MR and from sensors S.sub.i to the sensor assignment device SAD, wherein the sensors S.sub.i are acquiring sensor data SD in dependence on the movements M.sub.m of the machine parts MP.sub.j.

(13) A controller CO of the machinery MA is connected in a forward direction to actuators A.sub.k via a communications medium. The communications medium may, for example, be a wired star network, a wired serial bus, or a wireless medium. The controller CO is also connected in a backward direction to sensors S.sub.i via one of the mentioned communications media. In the following it is supposed that the affiliation of at least one of the sensors S.sub.i to the corresponding moveable machine part MP.sub.j is unknown at start-up of the machinery MA. On the other hand, it is supposed that the controller CO has all necessary information and means for instructing and causing at least one of the actuators A.sub.k to drive a movement Mm of one of the machine parts MP.sub.j. During the movements Mm the sensors SD record sensor data SD. Depending on a consistency of received sensor data SD, the sensor assigner SA associates at least one of the sensors S.sub.i to at least one of the machine parts MP.sub.j. When however, the received sensor data SD is not adequately consistent, the sensor assigner SA does not associate any of the sensors to any of the machine parts MP.sub.j.

(14) A further refinement of the concept is to apply the concept (the learning strategy) in a multiple-step fashion as follows. The operations described above are performed in a first step employing movement instructions Ml for a first pattern of movements. Upon completion of the first step, sensor data SD is processed from a candidate sensor S.sub.i. This processed sensor data SD is employed for defining movement instructions MI for a second pattern of movements Mm taking into account the sensor data SD from the candidate sensor S.sub.i. By the second and optional further steps an identification and/or a role and/or a location information and/or an orientation information of one or more sensors S.sub.i can be refined and narrowed down step-by-step. This may be repeated until a sufficiently reliable map of affiliations between sensors S.sub.i and machine parts MP.sub.j is established.

(15) Ideally, at a start of a set-up phase all relevant actuators A.sub.k are inactive. Then, each actuator A.sub.k is instructed in turn to follow its pattern of movements M.sub.m. Alternatively, the assignment of sensors S.sub.i to machine parts MP.sub.j can be performed when most of the machine parts MP.sub.j are active (even machine parts MP.sub.j having the unassigned sensor S.sub.i may be already active). Supposed that all existing sensors S.sub.i are already assigned, the assignment process becomes relatively trivial when only one pair of machine part MP.sub.j and sensor Si is added at a time. The reliability of the determination of assignments can be enhanced by completing the learning steps for more than one actuator A.sub.k before making any final assignment decision. This can be done for all actuators A.sub.k that expect a same type number (or a common range of type number). In this case globally optimal decisions can be made, and inconsistencies between assignments can be identified. For example, when a single sensor S.sub.i shall be assigned to two different actuators A.sub.k belonging to two different machines this may indicate a consistency problem.

(16) Now, the suggested assignment method is elucidated by following examples:

(17) In the case of a linear stepper motor actuator A.sub.k, the sensor S.sub.i may be a linear position sensor. The pattern of movement M.sub.m is then a motion over a specified distance. The sensor data SD can be examined to find a movement M.sub.m over a same distance in the same direction. In a multiple-step approach, the fractional error for the first step can be calculated and used for predicting a fractional error of the second step. For example, when the applied movement M.sub.m was 1 cm, but the reported movement M.sub.m was 0.8 cm, for a further applied movement M.sub.m of 1 cm, a reported movement M.sub.m, of 0.8 cm fulfils a consistent expectation.

(18) In the case of a three-dimensional actuator A.sub.k (for example for moving a robot arm) a three axis sensor S.sub.i may be provided. Then, the pattern of movement M.sub.m may be a sequence of movements M.sub.m in each of three dimensions x, y, z. For example, when we note the three mutually normal dimensions as x, y and z with units of 1 cm then the movements M.sub.m can be x=x+1, x=x1, y=y+1, y=y1, z=1, z=z1. The correct three axis sensor S.sub.i reports these three successive forward-backward movements M.sub.m. In this case there may be some rotational transformation and a scaling error between the applied and the reported movements M.sub.m. Here, the angular transformation needed to maximise consistency between the applied and the reported movements M.sub.m can be computed. Too large angle differences may suggest either that a wrong sensor S.sub.i is being observed or (which may be more likely) that the sensor S.sub.i has been incorrectly mounted. In either event valuable information is obtained.

(19) In the case of a rotating platform the operations can be essentially the same as those for the linear stepper motor actuator A.sub.k except that the values applied and reported are angles rather than absolute distances.

(20) The suggested sensor assignment concept has the benefit that a requirement for a manual set up of associations between sensors S.sub.i and machine parts MP.sub.j is removed. Thereby, expensive work-time for setting up a machinery MA or replacing a sensor S.sub.i can be reduced. Configuration errors can be avoided, and implicit self-tests of the configuration can be performed.

(21) FIG. 4 shows a method 100 for assigning a sensor S.sub.i to a machine part MP.sub.j moveable by an actuator A.sub.k. The method 100 comprises following steps. In a first step 110 a movement instruction MI is transmitted to a distinct one of a plurality of actuators A.sub.k (step 110a) to move a distinct one of a plurality of machine parts MP.sub.j (step 110b). In a second step 120 sensor data SD are acquired by a subset of a plurality of sensors S.sub.i (step 120a). In a third step 130 sensor-specific degrees of correlation DC between said acquired sensor data SD and the movement instruction MI is determined. In a fourth step 140 those sensors S.sub.i are assigned to the distinct machine part MP.sub.j whose sensor-specific degrees of correlation DC exceed a predetermined threshold.

(22) The suggested sensor assignment device SAD has a movement instruction generator MIG, a sensor data receiver SDR, a degree of correlation determiner DCD, and a sensor assigner SA. The movement instruction generator MIG is prepared for generating 105 and submitting 110a a movement instruction MI to a distinct one of a plurality of actuators A.sub.k to move a distinct one of a plurality of machine parts MP.sub.j. The sensor data receiver SDR is prepared for receiving (step 120b) sensor data SD acquired in step 120a by a subset of a plurality of sensors S.sub.i. The degree of correlation determiner DCD is prepared for determining a sensor-specific degrees of correlation between said detected sensor data SD and the movement instruction MI. The sensor assigner SA is prepared for assigning those sensors S.sub.i to the distinct machine part MP.sub.j whose sensor-specific degrees of correlation DC exceed a predetermined threshold.

(23) While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit and scope of the present invention. The embodiments were chosen and described in order to explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

(24) What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein: