METHOD FOR AUTOMATICALLY CALIBRATING A SENSOR MODULE AND SENSOR MODULE FOR DETECTING MATERIAL CONTAINERS IN A STORAGE OR TRANSPORT SYSTEM

Abstract

A method for automatically calibrating a rocker-type sensor module having a position or acceleration sensor involves measuring a position of the sensor module as an angle relative to a fixed spatial direction, and outputting an output signal that depends on whether the measured angle is less than or greater than a switching angle. The output signal is set to a first output value if the measured angle exceeds the switching angle. The switching angle is set to a value corresponding to the measured angle minus an “off” free pivot angle, as long as the value of the measured angle continues to increase. The output signal is set to a second output value if the measured angle falls below the switching angle. The switching angle is set to a value corresponding to the measured angle plus an “on” free pivot angle, as long as the value of the measured angle continues to fall.

Claims

1-8. (canceled)

9. A method for automatically calibrating a sensor module formed as a rocker, the sensor module having which has a position or acceleration sensor, the method comprising: measuring, by the sensor module, a position of the sensor module as an angle relative to a fixed spatial direction; outputting, by the sensor module, an output signal that depends on whether the measured angle is greater than or less than a switching angle; setting the output signal to a first output value responsive to the measured angle exceeding the switching angle; setting the switching angle to a value equal to the measured angle minus an off free pivot angle as long as a value of the measured angle continues to increase; setting the output signal to a second output value responsive to the measured angle falling below the switching angle; and setting the switching angle to a value corresponding to the measured angle plus an on free pivot angle as long as the value of the measured angle continues to decrease.

10. The method of claim 9, wherein the setting of the switching angle to the value equal to the measured angle minus an off free pivot angle only occurs when the switching angle is exceeded by more than the off free pivot angle, and wherein the setting of the switching angle to the value corresponding to the measured angle plus an on free pivot angle only occurs when the switching angle is undershot by more than the on free pivot angle.

11. The method of claim 9, wherein the setting of the switching angle to the value equal to the measured angle minus an off free pivot angle and to the value corresponding to the measured angle plus an on free pivot angle occurs immediately after the switching angle is exceeded or undershot, respectively.

12. The method of claim 9, wherein a magnitude of the off free pivot angle and a magnitude of the on free pivot angle are predetermined.

13. The method of claim 12, wherein the magnitude of the off free pivot angle and the magnitude of the on free pivot angle are in a range of 25% to 40% of a maximum possible pivot range of the sensor module.

14. The method of claim 9, wherein the measured angle is measured relative to a direction of a weight force.

15. The method of claim 9, wherein the output signal is output wirelessly.

16. A sensor module for detecting material containers in a storage or transport system, the sensor module comprising: a position or acceleration sensor, via which a position of the sensor module can be measured as an angle relative to a fixed spatial direction; and an evaluation unit that evaluates a signal of the position or acceleration sensor and that outputs an output signal as a function of the measured angle, wherein the evaluation unit is configured to set the output signal to a first output value responsive to the measured angle exceeding the switching angle; set the switching angle to a value equal to the measured angle minus an off free pivot angle as long as a value of the measured angle continues to increase; set the output signal to a second output value responsive to the measured angle falling below the switching angle; and set the switching angle to a value corresponding to the measured angle plus an on free pivot angle as long as the value of the measured angle continues to decrease.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0014] The invention is explained in more detail below by means of an exemplary embodiment with the aid of figures, wherein:

[0015] FIG. 1 shows an isometric view of an exemplary embodiment of a sensor module attached to a roller conveyor;

[0016] FIG. 2 shows the position of roller conveyor levels and average switching point positions on the sensor module according to FIG. 1 at two different inclinations; and

[0017] FIG. 3a-e show the switching point positions of the sensor module according to FIG. 1 as well as the associated angular ranges for different sensor module positions and inclinations of the roller conveyor plane.

DETAILED DESCRIPTION

[0018] The exemplary embodiment of a sensor module 1 designed as a rocker shown in FIG. 1 is arranged on an inclined roller conveyor 3 by means of a holder 2. Also shown is the direction G of gravity and an angle γ between a principal plane H of the sensor module 1 and the direction G of gravity, which is indicative of the inclination of the sensor module about its bearing axis in space. The angle γ is the measured quantity of an acceleration or position sensor arranged in the sensor module 1, hereinafter referred to as sensor.

[0019] The weight distribution of the rocker, i.e., of the sensor module 1, is selected so that it assumes a rest position within the holder 2 due to gravity when not depressed. In this rest position, the rocker is shown in FIG. 1.

[0020] The position of the sensor module 1 is detected by the sensor in the form of the angle or a measured variable representing the angle, the measured value of which is converted into an output signal in an evaluation unit belonging to and integral with the sensor module 1, which signal represents an “off” or “free” state in the rest position. As soon as an object (not shown), for example a material container, is now located on the roller conveyor 3 above the rocker, this presses down the part of the rocker projecting upwards from the holder 2. This new position “pressed down” is in turn detected by the sensor arranged in the sensor module 1, whose measured value is now converted into an output signal representing an “on” or “actuated” state.

[0021] FIG. 2 shows, as an example of the invention, the arrangement according to FIG. 1, which is successively aligned in two exemplary planes with a first inclination R.sub.1 and with a second inclination R.sub.2 of the roller conveyor. Shown are roller conveyor 3, holder 2, and sensor module 1 with the second roller conveyor inclination R.sub.2, wherein the sensor module 1 is shown in a middle switching point position S.sub.2. The switching point position is in each case the position at which the signaling changes from the “on” state to the “off” state or vice versa. The associated geometry is drawn in solid lines. For the sake of clarity, only the roller conveyor plane R.sub.1 and a middle switching point position S.sub.1 are shown in dashed lines with respect to the first inclination.

[0022] In a sensor module according to the prior art, for example according to the publication DE 20 2017 103 459 U1, it is unavoidable to manually adjust the switching point position to the installation position so that a reliable switching of the output states takes place when the rocker is pressed down.

[0023] On the other hand, a sensor module 1 according to the application is set up to exhibit the signaling behavior described in FIG. 1 even with different installation positions, e.g., with the two inclinations R.sub.1 and R.sub.2 of the roller conveyor plane, without the need for a separate adjustment, in particular a manual adjustment from the outside, for this purpose.

[0024] In connection with FIGS. 3a-e, the following illustrates how a sensor module 1 according to the invention automatically adapts its signaling behavior to the inclination of a roller conveyor.

[0025] As an example, it is shown how the signaling is first adapted from a delivery state to a roller conveyor inclination R.sub.1. The roller conveyor inclination is then changed to a roller conveyor inclination R.sub.2 and it is shown how the sensor module adapts its signaling to the inclination R.sub.2.

[0026] In FIG. 3a, the line R.sub.1 symbolizes a roller conveyor at a first roller conveyor inclination R.sub.1. The sensor module according to the invention is attached to this roller conveyor in a possible delivery state in such a way that its main plane H lies in a middle range of a possible pivot range α. α is defined by the mechanical stops of the sensor module 1 in its mounting, which in practice, however, are usually not fully reached by the sensor module.

[0027] In this situation, the sensor module has a switching point position S which, for example, is preset at the factory in a delivery state or which is set randomly after a first energization of the sensor module. Around this switching point position S, the total free pivot angle Δ is spanned, which consists of the off free pivot angle Δ.sub.O on the off side of the switching point position and the on free pivot angle Δ.sub.I on the on side of the switching point position. For values of the angle γ that are in the invalid range U, the exemplary sensor module cannot be operated because of the sensor used. When using other sensors, this restriction may not exist.

[0028] In the sensor module 1, the switching point position is represented by a switching angle γ.sub.S. This switching angle γ.sub.S is stored, for example, in a memory of an evaluation unit of the sensor module 1. The output signal of the sensor unit 1 with the switching states “on” or “off” is set depending on a comparison of the measured angle γ with the switching angle γ.sub.S.

[0029] The following describes how the sensor module adapts to the inclination of the roller conveyor plane R.sub.1 from the described delivery state. In other delivery states, in particular if the switching point position S deviates very strongly from the switching point position shown, it may be necessary to let the sensor module run through the pivot range α in both directions as far as possible in order to carry out the adaptation process completely. As the average person skilled in the art will recognize, the mode of operation is based entirely on the processes described below, which is why this case is not described separately.

[0030] After the sensor module has been mounted and commissioned, it pivots to the “released” position in the absence of a container on the roller conveyor, wherein the main plane is either already in the off free pivot angle Δ.sub.O of the sensor or enters it after the switching point position S has been exceeded. In other words, as soon as the measured angle γ exceeds the switching angle γ.sub.S, the sensor module 1 outputs the output signal “off”. Now, if the measured angle γ continues to increase because the rocker continues to swing up and the measured angle γ becomes larger than the switching angle γ.sub.S plus the value of the off free pivot angle Δ.sub.O, the switching angle γ.sub.S is set equal to the measured angle γ minus the value of the off free pivot angle Δ.sub.O. In an alternative design of the method, it is also possible to set this value immediately when the measured angle γ exceeds the switching angle γ.sub.S, i.e., also when it is exceeded for the first time.

[0031] According to the application, the switching angle γ.sub.S is always tracked as the measured angle γ increases, so that the off pivot angle Δ.sub.O represents a type of (switch-on) hysteresis for the sensor module 1. The switching point position S is therefore pivoted along with it in a tracking manner at a constant distance from the main plane H. Since the total free pivot angle Δ is fixed relative to the switching point position S, this is also pivoted along with it so that, as shown in FIG. 3b, after the sensor module has been completely released, its main plane H is located close to the off-side leg of the pivot range α together with the leg of the off free pivot angle Δ.sub.O facing away from the switching point position S.

[0032] For better understanding, FIG. 3b also shows the switching point position S′ and the free pivot angle Δ′, which correspond to the switching point position S and the free pivot angle Δ from FIG. 3a.

[0033] If the sensor module is depressed from this position by the arrival of a container on the roller conveyor, the sensor initially retains the switching point position S. If the main plane H passes through the switching point position S during pivoting, the measured angle γ becomes smaller than the switching angle γ.sub.S, whereupon the output signal changes from “off” to “on”. From the position of the main plane H in which the leg of the on free pivot angle Δ.sub.I facing away from the switching point position S has been reached during further pivoting in the “depressed” direction, the switching point position S is pivoted along in a tracking manner with the main plane H at a constant distance. Or, related to the measured angle γ: As soon as the measured angle γ becomes smaller than the switching angle γ.sub.S minus the on free pivot angle Δ.sub.I, the switching angle γ.sub.S is set to the measured angle γ plus the on free pivot angle Δ.sub.I. Since the total free pivot angle Δ is fixed relative to the switching point position, the angle is also pivoted along so that, as shown in FIG. 3c, after the sensor module has been pressed down completely, its main plane H together with the leg of the on free pivot angle Δ.sub.I facing away from the switching point position S is close to the on side leg of the pivot range α.

[0034] FIG. 3d shows the situation after a change of the roller conveyor plane with the sensor module depressed from the first inclination corresponding to R.sub.1 to a second inclination corresponding to R.sub.2. Although such a change of the roller conveyor inclination does not usually occur in practice, this example is suitable to illustrate the operation of the automatic adjustment of the sensor module.

[0035] Due to the greater inclination of the roller conveyor plane R.sub.2, the angle γ of the sensor module main plane H decreases further. The pivot range α is fixed relative to the roller conveyor plane and thus follows its change in inclination. The pivoting motion that the sensor module performs relative to gravity for this purpose is similar to the pivoting motion in the “depressed” direction described in connection with FIG. 3c. As there, the switching point position S, i.e., the switching angle γ.sub.S and the total free pivot angle Δ are also pivoted here, so that the same situation as in FIG. 3c arises relative to the roller conveyor plane R.sub.1 after the inclination has been increased relative to the roller conveyor plane R.sub.2.

[0036] For better understanding, FIG. 3d also shows the switching point position S′ and the free pivot angle Δ′, which correspond to the switching point position S and the free pivot angle Δ from FIG. 3c.

[0037] If the sensor module is released from this position by removing the container on the roller conveyor, a process similar to that described in connection with FIG. 3b results. The sensor initially retains the switching point position S. If the main plane H passes through the switching point position S during pivoting, the signal changes from “on” to “off”. From the position of the main plane H in which, during further pivoting in the “released” direction, the leg of the off free pivot angle Δ.sub.O facing away from the switching point position S has been reached, the switching point position S is also pivoted along in a tracking manner at a constant distance from the main plane H by setting the switching angle γ.sub.S equal to the measured angle γ minus the off free pivot angle Δ.sub.O. Since the total free pivot angle Δ is fixed relative to the switching point position S, this is also pivoted, so that, as shown in FIG. 3e, after the sensor module has been completely released, its main plane H together with the leg of the off free pivot angle Δ.sub.O facing away from the switching point position S is located close to the off side leg of the pivot range α.

[0038] Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

LIST OF REFERENCE SIGNS

[0039] 1 Sensor module

[0040] 2 Holder

[0041] 3 Roller conveyor

[0042] H Main plane of sensor module

[0043] G Weight force

[0044] γ Measured angle between main plane of sensor module and direction of weight force

[0045] γ.sub.S Switching angle

[0046] R.sub.1 Roller conveyor plane with a first inclination

[0047] R.sub.2 Roller conveyor plane with a second inclination

[0048] S.sub.1 Middle switching point position for roller conveyor plane with a first inclination

[0049] S.sub.2 Middle switching point position for roller conveyor plane with a second inclination

[0050] S Switching point position

[0051] S′ Previous switching point position

[0052] α Possible pivot range of the sensor module

[0053] Δ Total free pivot angle

[0054] Δ′ Total free pivot angle according to previous figure

[0055] Δ.sub.O Off free pivot angle

[0056] Δ.sub.I On free pivot angle

[0057] U Invalid range