Patent Application
20230409044
The present invention is useful in the sector of automated or semi-automated industrial production lines. For example, and without limitation, it is useful on vehicle production or assembly lines.
More specifically, the present invention relates to a system and method for controlling access to nests, of those used on production lines, which enables safely controlling access to the inside of said nests, preventing accidents from happening due to the simultaneous entrance inside the nest by an operator, or a vehicle, which is in charge of supplying parts, and a robot in charge of assembling said parts.
Nowadays, on automated production lines, to mass produce a predetermined product the original product is placed on the production line and moves along said line by means of suitable mechanical systems, such that it passes through successive work stations in which new parts are assembled to the original product until the finished product reaches the end of the production line.
In these types of production lines, assembly robots are commonly used, which are in charge of taking the parts from a storage area and subsequently assembling them to the product on the production line.
The areas where the robots get the parts to be assembled are known as nests.
In most cases these nests are usually arranged in two facing access areas: a first area (which will henceforth be referred to as “collection area”) through which the assembly robot will access the inside of the nest to collect the part or parts to be assembled, and a second area (which will henceforth be referred to as “access area”), opposite the first area, through which access will be available to the inside of the nest to stock it with new parts.
Nowadays, it is common for these nests to be manually stocked by operators who periodically enter the access area and place new parts in the nests.
Furthermore, there are often hardly any safety measures, sometimes none at all, to control access to the nests, which can lead to accidents in which an operator enters the inside of the nest at the same time as a robot.
On the other hand, there has been a recent trend to increase the automation of these production lines, in which the use of automated guided vehicles (AGVs) to stock the nests is common.
AGVs are able to move in an autonomous manner due to the automatic guide means. Furthermore, AGVs also have safety systems configured to control the speed of the vehicle and even stop it, based on the obstacles detected on its path. Said guide means are often programmable and can store a predetermined route for the vehicle to follow. Likewise, said automatic guide means actuate the motor and the direction of the vehicle to steer it along said route. In order for the automatic guide means to physically identify the best route to take in the factory, said routes are commonly provided with one or several route guidance methods. The route guidance can vary based on the type of AGV.
Thus, for example, in the case of optically guided AGVs, the route guidance is based on strips of catadioptric mirrors placed along the route to be followed which can be detected by the automatic guide means, by means of photocells. On the other hand, in laser guided AGVs, the route guidance consists of a set of reflectors that are identified by the automatic guide means, by means of a rotary laser unit that sweeps the area, identifying the objects in its surroundings.
Without being exhaustive, there are other types of AGVs, such as wire guided AGVs, in which the route guidance consists of a wire installed below the ground of the factory, as well as AGVs that use computer vision.
To be able to extend the use of said AGVs and fully integrate them into applications in which they access nests on production lines, it would be necessary to first develop safety protocols and systems that control access of said vehicles to the inside of the nests at all times.
With the aim of solving the aforementioned drawbacks and problems in relation to the prior art, a first object of the present invention relates to a system for controlling access to at least one nest of a production line, said nest comprising an inside space delimited by a barrier, a parts collection area and a vehicle access area, the production line comprising safety means configured to send signals of an incident when an incident is detected on the production line, the access control system being characterized in that it comprises:
The access control system according to the present invention allows automated guided vehicles to safely access the nest given that when said vehicle reaches a predetermined distance, close enough to the access area for the entry of vehicles, a request for access to the nest is automatically sent. In response to said access request signal, the occupation detection means are checked to see if the space inside the nest is occupied. If the nest is occupied, the connection means are not activated and the AGV does not enter. If the nest is unoccupied, the connection means are activated and connect the vehicle to the safety means of the production line to check if the line is enabled or if an incident has occurred.
At this moment, the movement of the vehicle will be conditioned by the incidents that are transmitted through the connection means (which can be, for example, category 4 optical means), preventing the movement of the vehicle if there is an incident.
Furthermore, before allowing the vehicle access to the nest, the parts collection area will be closed, thereby preventing robots from accessing the space inside the nest and avoiding possible accidents inside the nest. The invention will also check at all times that a person can access the area of the nest where the AGV is operating.
Once the vehicle has completed its task in the nest, having delivered the corresponding parts, the vehicle will begin to exit the nest. When the vehicle exits the nest, the moment it exceeds the predetermined distance the connection means will be deactivated, ceasing to complement the safety of the vehicle, said safety thus being controlled again by the autonomous system of the vehicle. Then, as the vehicle continues to advance, the access request means will be deactivated.
In one embodiment of the invention, the system further comprises at least one safety mechanism by way of a “folding door” arranged in the vehicle access area, provided with at least one folding door and a safety sensor. In the preset position of the mechanism, it acts as a barrier or a door that prevents access to the space inside the nest from the sides.
In the case that someone tried to enter, they would have to open or further fold the door, which would activate the safety sensor. This activation activates a safety alarm so that if there is an access request it will be denied, said access request not being granted until the alarm is reset (after checking there is nobody inside).
The door is made of methacrylate so that it is transparent in any position and there is visibility at all times to see inside the nest.
The access request means can be implemented in different ways, depending on the needs of each particular case.
Thus, in one embodiment of the invention, which is preferred, arranged in the vehicle access area are two metal profiles, such that the ends of the metal profiles furthest from the nest are at the same predetermined distance from the vehicle access area, which the AGV must approach to request access. In this embodiment of the invention, the AGV comprises a pair of inductive sensors. This way, when the inductive sensors of the AGV detect one of the metal profiles, the AGV is at the predetermined distance to the nest.
The inductive sensors then inform the access request means and said access request means send the corresponding access request.
In one embodiment of the invention, which is preferred, the access request means comprise at least one emitting/receiving photocell (meaning a cell that integrates both an emitting and receiving photocell) arranged in the vehicle access area and at least an optical reflection device, for example a mirror, arranged in the automated guided vehicle (AGV). This way, when the vehicle reaches the predetermined distance to the vehicle access area, the beam emitted by the emitting/receiving photocell reaches the optical reflection means and is reflected, returning to the emitting/receiving photocell. The beam reflected by the optical reflection device is, in this specific case, the access request signal, such that by receiving it the occupation detection means are verified and the system according to the invention manages said access request.
In another embodiment of the invention, the access request means comprise an emitting photocell and a receiving photocell. Preferably, the emitting photocell is a category 4 single beam. This type of transmission is especially safe, since category 4 is a safety standard that certifies a maximum level of safety in the emission and transmission of the signal.
The receiving photocell, preferably category 4, is arranged in the automated guided vehicle and the category 4 emitting photocell is arranged in the vehicle access area to the nest.
In the embodiment of the invention described in the previous paragraph, when the vehicle reaches the predetermined distance, the beam emitted by the emitting/receiving photocell is reflected off the mirror of the AGV, this reflected signal being the access request signal, and when it is received, the occupation detection means are verified and the system according to the invention manages said access request.
In another embodiment of the invention, there is a portion of ferrous material and emitting/receiving means provided with at least one inductive sensor connected to a programmable logic controller of the AGV. When the vehicle reaches the predetermined distance to the vehicle access area, the inductive sensor detects the portion of ferrous material, sending a signal to the AGV as well as the access request, verifying the occupation detection means, and the system according to the invention manages said access request.
In another embodiment of the invention, the access request means comprise emitting/receiving means provided with two photocells, the beams of which are cross at a point situated at the predetermined distance to the vehicle access area, preferably as described in detail in standard IEC62046. When the vehicle reaches said point, the beams detect the vehicle. This detection of the vehicle is, in this specific case, the access request signal, such that by receiving it the occupation detection means are verified and the system according to the invention manages said access request.
The occupation detection means can be provided with a safety laser scanner housed inside the nest. They can also be provided with a photoelectric barrier arranged in the vehicle access area. More preferably, the occupation detection means are provided both with a safety laser scanner housed in the nest and a photoelectric barrier arranged in the vehicle access area.
The connection means, which transmit the emergency signals of the production line to the vehicle (AGV) preferably comprise a category 4 single beam emitter situated in the vehicle access area and a category 4 single beam receiver situated in the vehicle.
Likewise, the safety means on the line can be provided with a programmable logic controller (PLC). Said PLC would be the element in charge of emitting the signals of an incident when an anomaly is detected on the production line that could compromise safety during access to the nest.
A second aspect of the invention relates to a method for controlling access to at least one nest of a production line, said nest comprising an inside space delimited by a barrier, a parts collection area and a vehicle access area, the production line comprising safety means configured to send signals of an incident when an incident is detected on the production line, the access control method being characterized in that it comprises the following steps:
To complete the present description of the invention, and for the purpose of helping to make the technical features of the invention more readily understandable, in accordance with preferred practical exemplary embodiments thereof, said description is accompanied by a set of drawings constituting an integral part of the same, which by way of illustration and not limitation represent the following:
Throughout the present description, as well as in the attached figures, the elements with the same or similar functions will be designated with the same numerical references.
In the vehicle access area (1c) there are two doors (8), controlled by two respective door control safety sensors (8a). When the doors (8) open, they act as barriers, preventing access to the space inside the nest (1) from the sides.
In this particular embodiment of the invention, the access request means comprise two emitting/receiving photocells (3b) provided in the access area (1c) and two optical reflection devices (2b) provided in the vehicle (15). Furthermore, connection means comprise a single beam emitter (7b) and a single beam receiver (7a). Also provided are means for opening and closing (6) the parts collection area.
In this embodiment of the invention, in addition to comprising a photoelectric barrier (4b), the occupation detection means comprise a safety laser scanner (4a).
The access control system herein shown further comprises connection means (7b) and (7a). Also provided are means for opening and closing (6) the parts collection area.
In practice, it is possible that, although the space inside the nest (1) is unoccupied (meaning no robot (20) or supply vehicle (15) has entered), in said inside space (1) there could be a container intended for storing, for example, assembly parts. To prepare for this situation, the present invention envisages the possibility that the occupation detection means (4a) can be calibrated in such a way that they understand the space inside the nest to be empty when they detect only the presence of said container.
In this embodiment of
In the particular example herein shown, the access control system according to the invention is very similar to that shown in
In the example shown in
If the photoelectric barrier (4b) were previously crossed by a vehicle (15) or if the door (8) were moved, when the vehicle (15) is situated at the distance (d), activating the safety sensors (8a), the light beacon (9) is then activated, and until the barrier (4b) and the door (8) are reset by an operator, the vehicle (15) will not have access.
If the photoelectric barrier (4b) has not been crossed, or if the door (8) has not been moved, or if the system has been reset, the area inside (1) the nest is secure and a signal is sent to the connection means (7a) and (7b).
The connection means connect the vehicle (15) to safety means of the production line, configured to send signals of an incident when an incident is detected on the production line.
Once an inoccupation signal is received from the occupation detection means, the connection means emitter (7b) sends a category 4 single beam to the connection means receiver (7a), thus connecting the safety means of the production line to the vehicle (15).
If there is no incident on the production line, the vehicle (15) can then access the inside of the nest (1) and, in turn, if there were an incident, the vehicle (15) would be immobile until the same were solved.
Said access movement is schematically shown by the arrow in
In the example shown in
By going beyond the predetermined distance, the connection means cease to complement the safety of the vehicle (15), disconnecting the vehicle (15) from the safety means of the production line by interrupting the category 4 beam between the connection means (7a) and (7b), the vehicle (15) taking back its own safety system.
The present invention is not limited in any way by the embodiments herein disclosed. For a person skilled in the art, other possible embodiments that differ from those of the present invention will be evident in light of the present description. Thus, the scope of protection of the present invention is exclusively defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| P202031178 | Nov 2020 | ES | national |
This application is the United States national phase of International Application No. PCT/ES2021/070801 filed Nov. 8, 2021, and claims priority to Spanish Patent Application No. P202031178 filed Nov. 24, 2020, the disclosures of which are hereby incorporated by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2021/070801 | 11/8/2021 | WO |
