Patent Description:
In facilities such as factories and warehouses there is a need for the transport of products such as bottles, cans, boxes, and other goods. For example, the products need to be transported between different processing stations for, e.g., filling, labeling, packaging, or other processing. A preferred mode of transportation may involve carrying the products by one or more conveyor surfaces. During transport, the products may change between conveyor surfaces having different directions and/or velocities. This may also change the arrangement or flow of the products. For example, products may enter a first processing station in single file to be filled or labelled, while the files are stacked to enter a second station, e.g. for packaging. Controlling the transitions between different product flows, may present particular challenges. For example, when products are transported from a relatively fast moving conveyor to a relatively slow moving conveyor, or vice versa, there can develop an excess or shortage of products. Additionally or alternatively, when products are pushed onto another conveyor, they may need to adapt their velocity, sometimes in a different direction.

Typically, the transport of products can be controlled by monitoring and adjusting various transport conditions or parameters. Some parameters such as the relative velocities of the conveyor belts can monitored and controlled in a straightforward manner, e.g. adding velocity sensors. Other parameters such as the friction coefficient between the products and conveyor can be more difficult to determine and/or control. For example, <CIT> describes monitoring and removing contaminants from a conveyor surface based upon predicted frictional engagement qualities detected on a conveyor surface. As further background, <CIT> describes a rowing up method of vessels <CIT>discloses a method for controlling transport products according to the preamble of claim <NUM> and a system for controlling transport of products according to the preamble of claim <NUM>.

While the known methods and systems may provide further control by monitoring various parameters affecting the transport conditions, there remains a need for further improvement in controlling the flow of products without having to monitor every condition separately.

The scope of this patent is defined by the independent claims. Embodiments in the description and figures which do not fall within the scope of the claims are to be interpreted as examples or background information. Aspects of the present disclosure relate to a methods and systems for controlling the transport of products. Products are guided by at least one conveyor surface through a control zone while a flow profile of the products is measured and compared to one or more predetermined flow patterns. According to the independent claims, the flow profile is measured by a sensor device disposed adjacent the products, wherein the flow profile is measured by determining a respective distance between the nearest row of products and the sensor device, wherein the distance is measured from a single point on the sensor device, and as a function of at least one angle varying in a horizontal plane of the control zone. By measuring a flow profile, in particular side profile of products flowing through the control zone, their collective behavior can be determined. The inventors find that control parameters can be adjusted based on the measured product flow instead of trying to measure and control each of the circumstances. For example, it is not necessary or useful to measure and/or model the friction coefficient and conveyor velocities when each may affects to the resulting flow in an unpredictable manner based on a combination of effects. By instead using the flow profile as feedback for the control, the resulting flow can be maintained according to a predetermined optical pattern, or non-desired pattern can be avoided. There are particular advantages to the use of a LIDAR system. For example, the LIDAR can be used to measure the product flow by recording the lateral surfaces of the nearest row of products, even if there are additional rows behind, which can be inferred from the overall system layout. Accordingly, it is not necessary to rely e.g. on complicated camera systems or other sensor devices.

<FIG> illustrates controlling transport of products <NUM>. In one embodiment, the products <NUM> are guided by at least one conveyor surface <NUM> through a control zone <NUM>. In another or further embodiment, a flow profile "Fm" of the products <NUM> in the control zone <NUM> is measured. In another or further embodiment, the measured flow profile "Fm" is compared with one or more predetermined flow patterns P1,P2,P3. The transport can be controlled based on the comparison.

In some embodiments, the measured flow profile "Fm" indicates a spatial distribution of at least a subset of the products <NUM> in a horizontal plane of the control zone <NUM>. In other or further embodiments, the measured flow profile "Fm" comprise a set of spatial coordinates indicating locations of products <NUM> in the control zone <NUM>. For example, the spatial coordinates can be expressed in Cartesian coordinates X,Y and/or polar coordinates R,θ. In one embodiment, the coordinates may be converted, e.g. wherein the positions are measured in polar coordinates and stored or compared based on Cartesian coordinates. Alternatively, the coordinates are stored and/or compared in the coordinate system wherein they are measured.

According to the claimed invention, the flow profile "Fm" is measured from a lateral side 1a of the products <NUM>. In particular, the flow profile "Fm" is measured by a sensor device <NUM> disposed adjacent the products <NUM>. The flow profile "Fm" is measured by determining a respective distance R between the products <NUM> and sensor device <NUM>. The distance R is measured from a single point on the sensor device <NUM>. The distance R is measured as a function of at least one angle θ varying (at least) in a horizontal plane XY of the control zone <NUM>. Also other or further angles can be used.

In some embodiments, the sensor device <NUM> is configured to exclusively measure lateral surfaces 1a of products <NUM> directly facing the sensor device <NUM>. In other or further embodiments, the sensor device <NUM> is configured to exclusively measure a subset of the products <NUM> in a (single) row, e.g. closest to the sensor device <NUM>.

In some embodiments, e.g. as shown, wherein the products <NUM> are guided through the control zone <NUM> by a side rail <NUM> contacting the products <NUM> on a first side. In other or further embodiments, the flow profile "Fm" is measured by a sensor device <NUM> measuring a second side of the products <NUM>. For example, the second side is opposite the first side. In one embodiment, exclusively products <NUM> on the second side of the flow profile are measured. In another or further embodiment, the side rail <NUM> is at an angle with respect to a movement direction X of the conveyor surface <NUM>, wherein products <NUM> abutting the side rail <NUM> are forced by the rail to move partially transverse -Y to the movement direction of the conveyor surface determining the flow profile "Fm". In some embodiments, the flow profile "Fm" comprises a relatively wide stream of relatively slow moving products at a start of the control zone <NUM> being funneled into a relatively narrow stream of relatively fast moving products <NUM> at an end of the control zone <NUM>, or vice versa.

In a preferred embodiment, the sensor device <NUM> comprises an emitter for emitting a beam towards the products <NUM>, and a sensor for sensing a reflection of the beam from the products <NUM>. Most preferably, the flow profile "Fm" is measured by a sensor device <NUM> using LIDAR ("LIght Detection And Ranging" or "Laser Imaging Detection And Ranging"). LIDAR typically uses active sensors that supply their own illumination source. The energy source hits objects and the reflected energy is detected and measured by sensors. For example, the distance to the object is determined by recording the time between transmitted and backscattered pulses and by using the speed of light to calculate the distance traveled. LIDAR typically uses ultraviolet, visible, or near infrared light to image objects. Wavelengths may vary to suit the target: from about <NUM> micrometers infrared to approximately <NUM> UV. Typically, light is reflected via backscattering, as opposed to pure reflection one might find with a mirror. Different types of scattering are used for different LIDAR applications: most commonly Rayleigh scattering, Mie scattering, Raman scattering, and fluorescence. For example, <NUM>-<NUM> lasers are most common for non-scientific applications. The maximum power of the laser can limited, or an automatic shut off system which turns the laser off at specific altitudes is used in order to make it eye safe for the people in the ground. One common alternative, <NUM> lasers, are eye-safe at relatively high power levels since this wavelength is not strongly absorbed by the eye.

In some embodiments, the LIDAR can be used to measure also other or further features of the product flow. For example, the sensor device <NUM> is configured to simultaneously measure a position and velocity of the products <NUM>. Also other or further properties can be determined by the sensor device <NUM>. In one embodiment, the sensor device <NUM> is configured to measure a surface property of the products. For example, an amount or spectrum of the reflected light can be used to determine a reflection coefficient or other surface properties. While the preferred sensor device as described herein is based on LIDAR, also other or further sensor devices can be used to determine similar or additional characteristics of the product flow. For example, a camera can be used to record the product flow and used in combination with image recognition software to determine, e.g. a respective positon of the products. Also, a combination of a light source and sensors can be used to whether products cross a respective light beam there between.

In some embodiments, the predetermined flow patterns P1,P2,P3 comprise definition of one or more of an optimal, acceptable, or unacceptable flow pattern. In one embodiment, the predetermined flow patterns P1,P2,P3 comprise a first pattern P1 according to which the products <NUM> are intended to flow through the control zone <NUM>, e.g. in accordance with optimal processing conditions. For example, when comparison yields that the flow profile "Fm" is in accordance with the first pattern P1 it may be determined that no changes in control parameters are necessary and the process can continue as is. In another or further embodiment, the predetermined flow patterns P1,P2,P3 comprise a second pattern P2 according to which the products <NUM> are still allowed to flow through the control zone <NUM>, e.g. in accordance with acceptable processing conditions, but which are suboptimal. For example, when comparison yields that the flow profile "Fm" is in accordance with the second pattern P2 it may be determined that the process can still continue but one or more control parameters need to be adjusted, e.g. to regain the optimal processing conditions. In another or further embodiment, the predetermined flow patterns P1,P2,P3 comprise a third pattern P3 according to which the products <NUM> are not allowed to flow through the control zone <NUM>, e.g. in accordance with unacceptable processing conditions. For example, when comparison yields that the flow profile "Fm" is in accordance with the thirds pattern P3 it may be determined that the process can no longer continue, e.g. the processing is halted.

Also other or further conditions can be defined. For example, instead of determining whether a measured flow complies with the third pattern, it can also be determined that the flow does not comply with the first or second pattern. Also less or more than three patterns can be defined. For example, a single pattern can be defined where process parameters are exclusively adjusted when the flow complies with (or deviates from) the pattern. For example, more patterns like the second pattern can be defined wherein different process parameters are adjusted, or to a different degree, depending on the flow pattern.

Flow patterns can be defined in various ways. In some embodiments, one or more flow patterns P1,P2,P3 are set to determine whether the products flow through the control zone <NUM> by no more than a predetermined maximum of number Nmax of adjacent product rows and/or no less than a predetermined minimum of number of adjacent product rows. For example, in the embodiment shown, the ideal pattern P1 has a maximum Nmax of three adjacent files on the conveyor surface <NUM>. For example, this may depend on the diameter of the products, their packing, and/or position of the side guide <NUM>, e.g. rail. Of course this predetermined number can be different for other embodiments, e.g. one, two, three, four, five, six, et cetera. Under some circumstances, it can occur that an excess of products accumulates on one conveyor surface <NUM>, e.g. because another conveyor 10b surface is too slow, or subsequent processing station cannot handle the influx, e.g. there is a blockage. Also other or further conditions can be preferred as ideal. For example, the ideal pattern may comprise a minimum of at least a single row of products, or another predetermined minimum number of rows. If this is not the case, this may indicate a shortage of products, e.g. from the preceding processing station. These and other circumstances can be detected early by determining the flow profile "Fm" deviates from the ideal pattern P1.

In some embodiments, comparing the measured flow profile "Fm" to a predetermined flow pattern comprises determining whether the flow profile "Fm" complies with the predetermined flow pattern, or deviates from the predetermined flow pattern. In one embodiment, the predetermined flow patterns P1,P2,P3 are defined by dividing the control zone <NUM> into different areas. For example, the flow patterns are defined by the areas themselves, or a position of one or more borders there between, e.g. line segment. In some embodiments, the flow profile "Fm" complies with a predetermined flow pattern when the products <NUM> pass through a respective area of the control zone <NUM> corresponding to that flow pattern. In one embodiment, it is determined how many measurement positions of the flow profile "Fm" are within an area of one of the predetermined flow patterns P1,P2,P3. For example, the absolute or relative number of measurement points within an area corresponding to a specific pattern can be used to determine to what degree the product flow complies with that pattern. In one embodiment, when the number of points of the measured flow profile "Fm" within an area (or between respective borders) of one of the patterns exceeds a threshold minimum, corresponding adjustments can be implemented. In another or further embodiment, one or more overlap areas are determined by which the flow profile "Fm" intersects with one or more of the predetermined flow patterns P1,P2,P3. For example, it can be assumed that the flow profile "Fm" represents a frontal border of the product flow which can be extended to an area between the frontal border and the backside border, e.g. side guide <NUM>. For example, a magnitude of the overlapping area can be a measure for how much the flow profile "Fm" complies with a predetermined flow patterns. In one embodiment, when the area of overlap, e.g. between the flow profile "Fm" and one of the patterns, e.g. P2 or P3, exceeds a threshold area, corresponding adjustments can be implemented.

In some embodiments, the flow profile "Fm" is measured at different instances of time. For example, the flow profile "Fm" is determined to comply with, or deviate from, a predetermined flow pattern, when products <NUM> are measured to reside in (flow through) a respective area of the control zone <NUM> during multiple different instances of time, e.g. period of time. For example, a minimum threshold time period is used to distinguish more structural deviations of the flow profile "Fm" from one flow pattern to the next. Also combinations are possible. For example, an area of overlap or number of points in an area can be integrated or added for different instances of time. Accordingly, a more structural deviation can build up.

In some embodiments, one or more control parameter are adjusted according to a proportional, integral, and/or derivative (PID) controller, e.g. taking as input the number of points or overlapping area, optionally integrated over time, and proportionally adjusting a control parameter. For example, the integrated deviation from, or compliance with, a flow pattern may determine an amount adjustment of a control parameter such as the conveyor velocities V1, V2 or e.g. a shape of the side guide <NUM> by adjusting the guide actuators <NUM>.

In some embodiments, one or more control parameters determining the flow profile of the products are adjusted in response to determining that the measured flow profile "Fm" complies with, or deviates from, one of the predetermined flow patterns P1,P2,P3. In one embodiment, adjusting the control parameters includes adjusting a velocity V1,V2 of one or more conveyor surfaces <NUM>,<NUM> transporting the products through the control zone <NUM>, before the control zone, or after the control zone. In another or further embodiment, adjusting the control parameters includes adjusting a position and/or angle of a side rail <NUM> guiding the products over the at least one conveyor surface <NUM>. In another or further embodiment, adjusting the control parameters includes adjusting a friction coefficient between the conveyor surface <NUM> and products <NUM>, e.g. initiating or adjusting cleaning and/or lubrication of one or both of the surfaces of the conveyor or products.

Also other or further control parameters can be adjusted, e.g. a rate of processing products in a processing station preceding or subsequent to the control zone <NUM>. Also combination of control parameters can be adjusted. For example, detecting a deviation from the optimal flow pattern may initially trigger adjustment of a first parameter such a conveyor velocity; and then if the deviation persists, adjustment of a second parameter such as the friction coefficient. As will be appreciated, the combination may yield both an immediate effect by the adjustment of velocity, and a long term effect by the adjustment of the friction coefficient. Some parameters can be temporarily adjusted, e.g. adding lubrication / cleaning, while other parameters may be more permanently adjusted, e.g. velocities V1,V2 or shape of the side rail <NUM>. Alternatively or in addition to adjusting control parameters, the comparison may also cause other types of feedback, e.g. visual or auditory feedback such as an alarm or other indication that the product flow complies with or deviated from preset conditions determined by one or more predetermined flow patterns P1,P2,P3.

<FIG> illustrates a sensor device <NUM> disposed substantially adjacent the products <NUM> and scanning their positions in a substantially horizontal plane X,Y. In one embodiment, e.g. as shown light rays L0 are emitted by the sensor device <NUM> substantially within a single plane. This may correspond to the light ray L0 being swept over only one angle θ. Preferably the light is substantially emitted along a horizontal plane XY and/or transvers to a lateral surface 1a of the products <NUM>, which is usually vertical. For example, the light ray L0 hits the lateral surface 1a at an angle of less than sixty degrees, preferably less forty five degrees, more preferably less than thirty degrees, or even less than twenty degrees. Typically, more light may be reflected, the smaller the angle of incidence with respect to a normal of the lateral surface 1a. For example, the sensor device <NUM>.

<FIG> illustrates scanning a position of the products at different heights Z. In one embodiment, e.g. as shown, the sensor device is configured to measure a position of the products <NUM> at different heights Z (of the same product). For example, the light rays L0 are emitted not only in a horizontal plane but e.g. two planes with different angles Φt and Φb. Advantageously, such additional measurement can be used to determine e.g. when products <NUM> tend to fall over, or have already fallen over. This may trigger adjustment of one or more control parameters, e.g. lubrication or cleaning to prevent the falling, or after the falling.

<FIG> illustrates a perspective camera image of products <NUM> moving through a control zone <NUM> between different conveyor surfaces <NUM>,10b. For example, white dots indicate exemplary positions where a light beam (not shown) from the side can reflect from the respective lateral sides 1a of the products <NUM>. In the embodiment shown, the conveyor surfaces are at a transverse angle with respect to each other.

<FIG> illustrates a corresponding measured flow profile "Fm". In one embodiment, e.g. as shown, the predetermined flow patterns may include a flow pattern P0 wherein the number of products is relatively low. For example, as shown, some of the measurement points may correspond to a reflection off the side rail <NUM> instead of the products <NUM>. In some embodiments, this may indicate a lack of products and can e.g. trigger increasing the rate of product from a preceding station or e.g. slowing a velocity V2 of the conveyor surface <NUM>. The control zone <NUM> may also exclude some areas, e.g. indicated by hatching, where it is not expected to find any products. For example, in calculating an overlap area, such excluded zones can be subtracted as a border beyond which no products are found.

<FIG> are similar to <FIG>, respectively, except having a different product flow. For example, the control parameters are adjusted to provide a product flow according to the optimal flow pattern P1.

Some aspects can be embodied as a non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause a system to perform the methods as described herein.

Claim 1:
A method for controlling transport of products (<NUM>), the method comprising
- guiding the products (<NUM>) by at least one conveyor surface (<NUM>) through a control zone (<NUM>);
- measuring a flow profile (Fm) of the products (<NUM>) in the control zone (<NUM>); and
- comparing the measured flow profile (Fm) to one or more predetermined flow patterns (P1,P2,P3) for controlling the transport based on the comparison;
wherein the flow profile (Fm) is measured by a sensor device (<NUM>) disposed adjacent the products (<NUM>), characterized in that the flow profile (Fm) is measured by determining a respective distance (R) between the nearest row of products (<NUM>) and the sensor device (<NUM>), wherein the distance (R) is measured from a single point on the sensor device (<NUM>), and as a function of at least one angle (θ) varying in a horizontal plane (XY) of the control zone (<NUM>).