Collision avoidance system and method for ground vehicles

Abstract

The present invention describes a collision avoidance system (1) for a ground vehicle, comprising: a first transceiver device (4) associated with an obstacle (B), configured to generate and transmit one or more radio signals (SG_B_i) at pre-established time intervals, the first radio signal (SG_B_1) carrying an obstacle identification code (ID_1); a second transceiver device (3) associated with a ground vehicle (A), configured to transmit one or more radio signals (SG_A_i) and receive one or more radio signals (SG_B_i) including the first radio signal (SG_B_1) carrying the obstacle identification code (ID_1); and a second transceiver device (4) for processing collision data of the vehicle (A). The present invention further describes a method and a computer program product for detecting a high probability of collision between the ground vehicle (A) and the obstacle (B), the method comprising: a first calculation module (21) configured to determine a trajectory (D_TRJ) of the ground vehicle (A) and the obstacle (B) as a function of the radio signals (SG_B_i) and the radio signals (SG_A_i), a second calculation module (23) configured to determine a collision probability between the ground vehicle (A) and the obstacle (B) based on the trajectory (D_TRJ), and a warning module (24) configured to generate and transmit a collision probability signal (S_COLL) between the ground vehicle (A) and the obstacle (B) in response to a high collision probability between the ground vehicle (A) and the obstacle (B).

Description

[Technical field]

[0001] The present invention relates to a collision avoidance system and method for ground vehicles.

[0002] In particular, the present invention relates to systems and methods for predicting and preventing collisions for forklifts operating both indoors and outdoors. [Background technology]

[0003] The reduction and prevention of accidents involving ground vehicles, especially in the workplace, is of paramount importance in all industrial sectors, especially in those where workers are in direct contact with moving vehicles (both conventional and autonomous), potential obstacles and both fixed and self-propelled machinery that pose potential risks to humans.

[0004] When self-propelled machinery or vehicles collide with people in the workplace, many very serious injuries can occur, including serious or even fatal injuries.

[0005] The risk of collision between the self-propelled vehicle and the operator occurs, for example, on construction sites, port areas, warehouses, storage areas, etc., where earth-moving or transport machinery is commonly operated. Similar problems also occur in general manufacturing plants, for example in foundries, paper mills, etc.

[0006] So-called active systems have been developed to prevent accidents in the workplace.

[0007] In the specific case of preventing collisions between people and vehicles, between vehicles or between vehicles and fixed obstacles, active systems are employed that use sensors mounted on the vehicle, which sensors are configured, for example, as so-called RFID tag or transponder readers.

[0008] The operator wears at least one RFID tag, for example attached to a helmet, jacket or other mandatory passive safety equipment. The operator driving the self-propelled vehicle is alerted by a central unit, thanks to the interaction of the sensor and the RFID tag, if the sensor attached to the vehicle detects the presence of a person within the range of the vehicle. Furthermore, other safety measures may be activated, for example slowing down the vehicle, if the presence of a person within the range of the vehicle is detected. Similarly, fixed or moving obstacles may be equipped with RFID tags. Thus, the use of RFID transponder technology for the active prevention of accidents in the workplace is well known. This known technology provides a system comprising at least one sensor and one or more transponders or RFID tags that can communicate with each other. Both the sensor or reader and the transponder or transponder each comprise two separate antennas.

[0009] The first antenna of the sensor and the first antenna of the transponder are each responsible for transmitting and receiving a signal (usually microwave) that has the function of "waking up" or activating the RFID transponder, which is usually in a dormant state in order to save energy.

[0010] The transponder is activated upon entering the sensor's control volume or prohibited range.

[0011] A second antenna of the transponder or transponder and a corresponding second antenna of the sensor allow transmission from the transponder to the sensor and / or from the sensor to the transponder on a channel (usually a radio frequency) different from the channel on which the transponder's activation signal is emitted.

[0012] Applications of this technology are known in the active prevention of accidents in the workplace, in particular to prevent collisions between ground operators and vehicles. At least one sensor (usually several sensors) is mounted on the vehicle, while the operator wears at least one transponder. When the operator comes within range of one of the sensors mounted on the vehicle, the sensor activates the transponder, which issues an alert.

[0013] The above systems have proven to be useful tools in preventing accidents in the workplace.

[0014] Known systems have recognized the problem that signal interference can occur, especially in enclosed environments such as warehouses, factories, and other work environments. Indeed, many current navigation systems lose signal in the presence of objects or interference conditions. This is particularly problematic in buildings that are often crowded with objects of various kinds.

[0015] However, there is still room to further increase the achievable safety level. Summary of the Invention

[0016] One of the aims of some embodiments of the invention described herein is to improve the safety level and ergonomics of this type of active protection system.

[0017] A further object of the present invention is to increase accuracy by eliminating false positives throughout location determination.

[0018] Another object of the present invention is to provide a collision avoidance system and method for ground vehicles operating in a work environment, which is able to guarantee a high level of safety.

[0019] It is a further object of the present invention to provide a collision avoidance system and method for ground vehicles operating in a work environment that is efficient.

[0020] A further important object of the present invention is to provide a collision avoidance system and method for ground vehicles operating in a work environment that is reliable, easy to implement and easy to use.

[0021] In a first aspect of the present invention, the above object is achieved by a collision avoidance system for a ground vehicle operating in a work environment according to what is disclosed in claim 1.

[0022] Advantageous embodiments are disclosed in the dependent claims 2 to 13.

[0023] In a second aspect of the present invention, the above object is achieved by a collision avoidance method for a ground vehicle operating in a work environment according to what is disclosed in claim 14.

[0024] In a third aspect, the present invention describes a computer program which, when executed on a computer, performs at least one or more steps of the method according to the second aspect of the invention according to what is disclosed in claim 15.

[0025] Generally speaking, the present invention provides the following technical advantages: Allows for increased safety for ground vehicles and operators operating in enclosed areas.

[0026] The mentioned technical effects / advantages, as well as other technical effects / advantages of the present invention, will become apparent in more detail from the following provided description of exemplary embodiments, provided as rough and non-limiting examples with reference to the attached drawings, in which: [Brief description of the drawings]

[0027] In order to better understand the invention and to appreciate its advantages, some non-limiting exemplary embodiments are described below with reference to the accompanying drawings, in which: FIG. [Figure 1] 1 shows an example of a system of the present invention adapted to reduce the likelihood of a collision between a ground vehicle operating within a workplace and a possible obstacle. [Diagram 2]FIG. 2 is a block diagram of the system of FIG. 1. [Diagram 3] 1 illustrates non-limiting examples of ground vehicles. [Figure 4] A diagram showing the time division of tags in terms of time slots is shown. [Figure 5a] 1 illustrates an example of a method for identifying and tracking the nearest ground vehicle to a given tag. [Figure 5b] 1 illustrates an example of a method for identifying and tracking the nearest ground vehicle to a given tag. [Figure 5c] 1 illustrates an example of a method for identifying and tracking the nearest ground vehicle to a given tag. [Figure 6] 13 shows a schematic diagram of an example of the calculation of collision probability via trajectory calculation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In the following description, it should be noted that identical or similar blocks, components, or modules are designated in the figures with the same reference numbers even when illustrated in different embodiments of the present invention.

[0029] With reference to the cited figures, a collision avoidance system for ground vehicles operating in a work environment according to the present invention is generally indicated by the reference numeral 1 in the block diagram of Figure 2. One part of the system is mounted on at least one ground vehicle A and another part is associated with possible obstacles B.

[0030] Obstacle B may consist of stationary or moving objects, machines, and / or people.

[0031] Obstacle B may also be a second ground vehicle that is capable of moving relative to the first vehicle A.

[0032] In particular, the ground vehicle may be a forklift or an autonomous ground vehicle.

[0033] In a first aspect, the present invention relates to a collision prevention system 1 for a ground vehicle comprising a first transceiver device 4 associated with an obstacle B configured to generate and transmit one or more radio signals SG_B_i at predetermined time intervals (e.g. periodically), where the first radio signal SG_B_1 carries an obstacle identification code ID_1, and a second transceiver device 3 associated with a ground vehicle A configured to generate and transmit one or more radio signals SG_A_i and to receive said one or more radio signals SG_B_i, including the first radio signal SG_B_1 carrying the obstacle identification code ID_1, generated by the obstacle B.

[0034] A radio signal SG_A_1 generated by a second transceiver device 3 associated with ground vehicle A carries vehicle A's identification code ID_2.

[0035] The first transceiver device 4 is configured to receive said one or more radio signals SG_A_i transmitted by a second transceiver device 3 associated to the ground vehicle A.

[0036] The collision avoidance system 1 for a ground vehicle operating in a work environment further comprises a processing unit 20 configured to process the collision data of the vehicle A. The processing unit 20 comprises: a first calculation module 21 configured to determine a trajectory D_TRJ of a ground vehicle A and an obstacle B as a function of said radio signal SG_B_i and said one or more signals SG_A_i; a second calculation module 23 configured to determine a collision probability between the ground vehicle A and the obstacle B based on the trajectories D_TRJ of the ground vehicle A and the obstacle B; and a warning module 24 configured to generate and transmit a collision probability signal S_COLL between the ground vehicle A and the obstacle B in response to a high collision probability between the ground vehicle A and the obstacle B.

[0037] In particular, there is advantageously present a comparison module (not shown in the figures) configured to compare the collision probability signal S_COLL between the ground vehicle A and the obstacle B, received from the third calculation module 23, with a pre-set threshold value stored in a memory unit. In this case, the warning module 24 is configured to generate and transmit the collision probability signal S_COLL between the ground vehicle A and the obstacle B as a function of a match OK of the comparison made by the comparison module.

[0038] It should be noted that, generally, in this context and in the claims that follow, the processing unit 20 is considered to be divided into separate functional modules (storage modules or operation modules) for the sole purpose of clearly and completely describing its functionality.

[0039] Such a processing unit may comprise a single electronic device suitably programmed to perform the functions described, and the various modules may correspond to hardware entities and / or routine software that are part of the programmed device.

[0040] Alternatively or additionally, these functions may be performed by several electronic devices on which the aforementioned functional modules may be distributed.

[0041] Processing unit 20 may also utilize one or more processors to execute instructions contained in memory modules.

[0042] If there is more than one ground vehicle and / or multiple obstacles, each will house at least one transceiver unit 3,4.

[0043] Advantageously, the first calculation module 21 comprises a first calculation sub-module 21a configured to calculate the relative distance D_REL between the ground vehicle A and the obstacle B based on the exchanged signals SG_B_i, SG_A_i, and a second sub-module 21b configured to calculate the relative angle A_REL between the ground vehicle A and the obstacle B in a given reference system S_RIF based on the signals SG_B_i received from the transceiver device 3.

[0044] For example, the reference system S_RIF may be a two-dimensional and / or three-dimensional Cartesian coordinate system associated with vehicle A.

[0045] In a first location operation mode between ground vehicle A and obstacle B, only one message SG_B_1 is used and the processing unit 20 of ground vehicle A calculates the relative distance D_REL from obstacle B using the power of the received signals (both UWB and Bluetooth®).

[0046] The angle at which ground vehicle A sees obstacle B (so that the reference frame S_RIF is aligned with vehicle A) can be calculated from vehicle A upon receipt of message SG_B_i using the angle of arrival (AoA) technique using multiple antennas.

[0047] The angle at which obstacle B sees vehicle A (so that the reference frame S_RIF is aligned with obstacle B and not with the vehicle as before) can also be calculated by vehicle A using the Bluetooth® Angle of Departure (AoD) technique. In this case, obstacle B emits signal SG_B_1 from multiple antennas and the vehicle receives it with only one antenna. Alternatively, upon receiving signal SG_B_1, vehicle A can use the difference in time of arrival (TDOAUWB technique, or difference in time of arrival) of signals SG_B_i from three or more Type 3 transceivers to calculate both the relative distance D_REL and the angle A_REL.

[0048] In the second localization operating mode between ground vehicle A and obstacle B, only two messages SG_B_1, SG_A_1 are used. By signal SG_B_1 obstacle B transmits its identification code ID_1. If it is known, obstacle B also transmits its last calculated position relative to vehicle A. By signal SG_A_1 the vehicle transmits a time T_reply_A (estimated elapsed time from the start of reception of message SG_B_1 to the start of transmission of signal SG_A_1) to obstacle B, which will be used to calculate the travel time and then the relative distance D_REL between vehicle A and obstacle B. For this calculation the formula TOF=(t2-t1-T_reply_A) / 2 can be used.

[0049] The angle that obstacle B forms with respect to vehicle A is calculated using the AoA technique, using multiple antennas, upon receipt of message SG_B_i.

[0050] In a third location operation mode between ground vehicle A and obstacle B, three messages SG_B_1, SG_A_1, and SG_B_2 are used.

[0051] In detail, by means of the signal SG_B_1 the obstacle transmits its identification code ID_1. By means of the signal SG_A_1 vehicle A can transmit to obstacle B its previously calculated position.

[0052] Subsequently, obstacle B generates and transmits a signal SG_B_2 including the time T_round_B (the time elapsed from the start of transmission of SG_B_1 to the start of reception of SG_A_1) and T_reply_B (the estimated time elapsed from the start of reception of SG_A_1 to the start of transmission of SG_B_2), which will be used to calculate the travel time. The relative angle A_REL that obstacle B forms with respect to vehicle A is calculated using the AoA technique using multiple antennas upon reception of message SG_B_2. At the end of the exchange of three messages, the processing unit 20 of vehicle A uses the processing times (round trip and reply) of both obstacle B and vehicle A together with the arrival time of the final package to perform the calculation of the relative distance D_REL of obstacle B. In this case, the calculation of D_REL and the angle A_REL will be more accurate.

[0053] In the three location operation modes, the relative distance D_REL between ground vehicle A and obstacle B, and the angle of obstacle B's tag relative to ground vehicle A are calculated by utilizing the reception of the last message by two or more antennas.

[0054] The collision avoidance method for ground vehicles of the present invention includes steps or phases for identifying and tracking ground vehicles or obstacles (associated with tags) that are close to a given vehicle and therefore have a high probability of colliding with that vehicle.

[0055] In particular, the steps of identifying and tracking vehicles proximate to a vehicle are performed using UWB technology.

[0056] In particular, the method is based on a continuous exchange of messages between the tag and its nearest vehicle.

[0057] The exchange of messages between a given tag and the vehicle allows the location of the tag relative to the vehicle to be determined as described above.

[0058] The Tag initiates the message exchange with a first initial request message (SG_B_1). The message exchange can be of two types: 1. Specific Exchange (IE), i.e. a message exchange in which the initial request message contains a unique destination ID and only the vehicle carrying that ID can respond; 2. Broadcast exchange (BE), i.e., a message exchange in which the initial request message does not contain a specific destination ID and all vehicles within range can respond.

[0059] As shown in FIG. 4, each tag is configured to divide time into time slots numbered "Slot_1", "Slot_2", "Slot_3", ..., "Slot_N".

[0060] In each time slot "Slot_i", the tag can perform one or more of the following steps: -Maintain a memory for each vehicle exchanging messages. In particular, at least the type of exchange performed, the (calculated or estimated) spatial distance from the tag, and the time offset of the start of the message exchange (relative to the start of the time slot). An example of an implementation for tracking this information is to store a table in memory. This is the "vehicle table". This table contains at least the following fields for each vehicle with which the tag exchanges messages: vehicle ID (unique in the table), spatial distance from the tag (Euclidean or other), type of exchange performed and time offset. This table can contain N records, sorted by increasing distance value, and updated after a possible message is exchanged in each time slot. If the distance value of vehicle VA is less than the distance value of vehicle VB, vehicle VA is considered to be closer to the tag of vehicle VB. Also, the closest vehicle s (where s<=N) known to the tag is the first vehicle s included in the vehicle table.

[0061] - Manages the exchange of up to n_ie (greater than or equal to 1) IE messages and up to n_be (greater than or equal to 1) BE messages with different vehicles (n_ie+n_be).

[0062] - Message exchanges can be shifted to occur within certain time slots to avoid RF collisions.

[0063] -BE messages are always executed.

[0064] A -IE message can only be executed if there is at least one vehicle responding from the previous time slot.

[0065] At the end of the timeslot message exchange, the vehicle table is updated and sorted with the new information obtained as a result of the message exchange, and the target ID for subsequent IE messages is calculated.

[0066] -The next IE message will be addressed to the first n_ie vehicle that appears in the vehicle table.

[0067] -If there is no response to a BE message, the tag can decide whether to execute the next BE message at a new offset time (relative to the start of the time slot). Furthermore, if this BE was responded to in the previous time slot from vehicle Az, the tag can decide to remove Az from the vehicle table.

[0068] If the vehicle Ay does not respond to the IE message for a certain number of consecutive J times, the following occurs: a) If there is no response from the BE message, then only one BE message will be executed in the following time slot. Furthermore, Ay is deleted from the vehicle table.

[0069] b) If it has responded with one or more BE messages, the vehicle Ay is removed from the vehicle table. At the end of the time slot, after updating and sorting the vehicle table, a selection is made whether this IE will be directed in the next time slot to the first vehicle Ax in the table for which a BE type exchange has taken place. -The message exchange to which the vehicle responded will also maintain its current offset (relative to the start of the time slot) in subsequent time slots.

[0070] For each time slot “Slot_i”, vehicle A may perform one or more of the following steps: - Vehicle A maintains a memory of the current slot number of each tag it communicates with. The tag's timeslot number may be transmitted by the tag itself, or the vehicle may infer it knowing the duration of the timeslot and the arrival time of the message from the tag. - Exchange messages with a predefined tag only once. Vehicle A may respond to the broadcast exchange immediately or may wait for a random time between 0 and a time T_Wait. The random time may be pre-configured or dynamically adjusted. If the received power of the first message SG_B_1 is less than a predefined threshold, there is a possibility that the tag will not respond. - In each time slot or in each n1 (n1=1, 2, 3, ...) time slots, it may respond to a broadcast exchange from the same tag. This may be pre-configured or dynamically adjusted.

[0071] This method is efficient both in terms of energy and in terms of UWB channel occupancy, since the tag does not communicate with all vehicles present to detect possible collisions, but instead tries to communicate with the spatially closest and therefore most relevant vehicles.

[0072] Furthermore, this method does not require the tag to know in advance the possible vehicles (i.e., their identities) that it may come into contact with.

[0073] This means that the tag does not have to be reconfigured every time.

[0074] Finally, the method guarantees that the obstacle (tag) is detected by the n_ie+n_be*n1 closest vehicles.

[0075] The exchange of IE messages from the tag to the same vehicle will be exchanged with a frequency of 1 / T_slot (where T_slot is the duration in seconds of a timeslot, typically T_slot=0.1 seconds). The exchange of BE messages from the tag to the same vehicle will be exchanged with a frequency of 1 / (n_1*T_slot).

[0076] In practice, n_ie=n_be=1 and n1=2 is a good choice.

[0077] Figures 5a, 5b and 5c show an example of the implementation of the method according to the invention. In figure 5c, it is assumed that the parameters n1, n_ie and n_be are all equal to 1.

[0078] FIG. 5a shows the distance of a first vehicle VA and a second vehicle VB from the tag.

[0079] Instead, FIG. 5b shows the distances of two vehicles VA and VB from the tag from the 300 ms instant in FIG. 5C.

[0080] The figure shows two vehicles (VA and VB) in the vicinity of a given tag.

[0081] Up to 300 ms, the first vehicle VA is closer to the tag than the second vehicle VB (Figure 5a).

[0082] At time 300 ms, the first vehicle VA moves away and the second vehicle VB approaches the closest tag of the first vehicle VA (Figure 5b).

[0083] In the first time slot (Slot_1), the tag only performs message exchange in BE mode. The first vehicle VA responds by sending its ID to the tag, so in time slot slot_2, the tag performs IE with the first vehicle VA and another BE to search for the presence of another vehicle. The second vehicle VB also responds with a BE, so the relative offset of both messages will be maintained.

[0084] In time slot slot_3, the sequence of message exchanges is repeated exactly since the first vehicle VA is closer to the tag relative to the second vehicle VB.

[0085] Also, in time slot slot_4, the message exchange sequence is repeated in the same manner as in time slot_2 and time slot_3.

[0086] At the end of time slot slot_4, the tag realizes that the first vehicle VA is far away, while the second vehicle VB is closest.

[0087] In the following time slot, slot_5, the system executes a second vehicle, VB, and IE.

[0088] An example of the computation of collision probability through trajectory computation is shown in Figure 6. In this figure, ri denotes the position of an obstacle (tag) at time slot slot_i, and vi denotes the velocity of the obstacle at time slot slot_i.

[0089] In FIG. 6, the current time slot is number 3 (slot_3).

[0090] The past trajectories are the set r0, v0, r1, v1, r2, v2, r3, v3.

[0091] The predicted trajectory is the set of r3, v3, r_impatto, v_impatto, r4, and v4.

[0092] Time to impact = impact distance / |v3|, where |v3| denotes the strength of vector v3.

[0093] The vehicle maintains the past trajectory of the obstacle given a set of positions and velocities relative to the vehicle for each time slot up to the current time slot.

[0094] From the past trajectory of the obstacle, the vehicle calculates the predicted trajectory for the next N time slots. From the predicted trajectory and geometric information of the vehicle (footprint), the points where the vehicle may collide with the obstacle are calculated in relative time before the collision.

[0095] Finally, the probability of collision is defined by assigning a probability of collision value to each value of the magnitude of "time before collision." For example, if the "time before collision" is less than 2 seconds, the probability of collision can be said to be equal to 1.

[0096] If the "time before collision" is greater than 2 seconds but less than 4 seconds, the collision probability is 0.8, etc.

[0097] The predicted trajectory may be calculated, for example, by assuming that the vehicle continues to move from its current position at its last calculated speed.

[0098] The described method is efficient both in terms of energy and in terms of UWB channel occupancy.

[0099] This is because in each time slot, the tag performs up to (n_ie+n_be) message exchanges to detect possible collisions with obstacles. This is possible because the tag only tries to communicate with the spatially closest obstacles.

[0100] Furthermore, this method does not require the tag to know in advance the possible vehicles (i.e., their identities) that the tag may come into contact with, which means that the tag does not need to be reconfigured every time.

[0101] The signals SG_1, SG_2 generated and transmitted by each of the transceiver devices 3, 4 present in the system 1 are advantageously ultra-wideband (UWB) type signals.

[0102] Ultra-wideband type signals are defined as radio frequency (RF) signals that occupy a portion of the frequency spectrum that is greater than 20% of the central carrier or have a bandwidth greater than 500 MHz. UWB is a communication channel that spans a large portion of the frequency spectrum. This allows UWB transmitters to transmit large amounts of data while consuming very little transmission energy. UWB may be used to determine positioning by obtaining the distance between a reference point and an obstacle using the time difference of arrival ("TDOA") of the RF signal, or by precisely measuring the distance using two-way ranging techniques ("TWR").

[0103] Alternatively, the signals transmitted by the transceiver devices 3 and 4 are Bluetooth® signals.

[0104] To alleviate the occupancy of the UWB band and therefore reduce the possibility of collisions on the channel, additional transceivers may be introduced in the vehicle and tags operating in different RF bands (e.g., BLE or RFID), especially in situations where there are many tags in the vicinity of the vehicle.

[0105] This band is called the supported RF channel.

[0106] Furthermore, these transceivers are connected to UWB units so that information (eg ignition signals) can be transmitted.

[0107] Typically, through message exchanges on a support channel, the tag attempts to detect the presence of vehicles in its immediate vicinity.

[0108] If a vehicle is detected, a less accurate estimate of its distance is calculated, typically using the received signal strength. If this estimate is below a certain threshold, the tag activates the operation of its UWB system for more accurate location determination and suspends the supporting transceiver.

[0109] When the tag detects that no vehicles are closer than a certain threshold, it pauses the UWB system and activates the supporting transceiver.

[0110] Below are two possible options to initiate the exchange of support messages between the tag and the vehicle: 1) The vehicle always listens for messages in the supported bands and responds to messages transmitted by the tag.

[0111] The tags will periodically exchange messages on a support channel. For this option, BLE technology will preferably be used. 2) The vehicle periodically transmits a message on the support channel, which can be received by the tag by continuously or periodically listening to the support channel. For this option, RFID technology would preferably be used.

[0112] In a situation where a collision risk probability is detected, the warning module 24 transmits a collision probability signal S_COLL to the control module 5 of the ground vehicle A. In particular, the collision risk probability occurs when the collision probability S_COLL exceeds a threshold value that may be pre-established and stored in a memory unit present in the system 1, and above which the warning module 24 transmits the collision probability signal S_COLL to the control module 5.

[0113] In this case, the control module 5 of vehicle A is configured to send an appropriate command signal S_COM to the controller 7 of vehicle A, so that the controller 7 can intervene in vehicle A in case of a collision risk.

[0114] Possible examples of vehicle intervention modes include emergency activation of the vehicle braking system, decelerating the vehicle, and activating vehicle steering members to avoid a possible collision with obstacle B.

[0115] In this way, via the control module 5, the processing unit 20 can act on the braking system and / or the engine system and / or the direction of the vehicle A depending on the collision probability signal S_COLL received from the warning module 24.

[0116] The warning module 24 is also configured to transmit the collision probability signal S_COLL to a warning device 6 configured to warn the driver of vehicle A and / or persons in the vicinity of vehicle A of a potentially dangerous situation.

[0117] Some non-limiting examples of possible control signals S_COM include at least one or more of the following: decelerating the vehicle, braking the vehicle, returning vehicle B to normal operation, and changing the direction of vehicle A relative to the impact direction of obstacle B in the impact maneuver.

[0118] Some non-limiting examples of possible warning devices 6 include at least one or more of a user interface, an audible warning device, and / or an optical warning device.

[0119] Advantageously, the transceiver 3 present on the ground vehicle A uses Angle of Arrival and / or Angle of Departure and / or Time Difference of Arrival (TDOA) methods to determine the relative position between the two transceivers 3 and 4 .

[0120] Advantageously, the first transceiver device 4 associated to obstacle B is configured to transmit at least one characteristic parameter P_B_i of the movement of obstacle B. In this case, the processing unit 20 comprises a calculation module 22 configured to calculate the movement of obstacle B as a function of said characteristic parameter P_B_i. Alternatively, a module for calculating the movement S_MOV (direction, speed, acceleration) of obstacle B may be present in obstacle B (not shown in the figure).

[0121] The optional characteristic parameters P_B_i, P_A_i of the possible movements of obstacle B transmitted by transceiver 3 or 4 include at least one or more of an acceleration signal S_ACC, an angular velocity signal S_GYR (i.e. angles spaced in unit time on various axes), a signal related to the angle relative to magnetic north S_MAGN, an atmospheric pressure signal S_BAR, a signal related to the type of obstacle (e.g. person, stationary object, moving object, etc.), and / or a temperature signal S_TEMP and / or a time signal (e.g. number of time slots or time since the transceiver 3 associated with the obstacle was turned on).

[0122] Advantageously, the transceiver 4 associated with obstacle B is operatively associated with an IMU (Inertial Measurement Unit) 30 including at least one or more of an accelerometer, a gyroscope, a magnetometer, a barometer, and / or a thermometer.

[0123] Advantageously, the second transceiver device 4 associated with the obstacle B is configured to receive the relative distance D_REL from the first transceiver device 3 associated with the vehicle A.

[0124] In this way, for example, if obstacle B is also a moving ground vehicle and there is a possibility of avoiding a collision with ground vehicle A, the probability of collision with vehicle A can be evaluated to avoid a possible collision.

[0125] Advantageously, the second transceiver device 3 associated with the ground vehicle A may be configured to receive at least one characteristic parameter P_A_i of the movement of the vehicle A, such as speed, acceleration, steering angle (detected by suitable sensors present on the ground vehicle or specially installed on the vehicle).

[0126] The second transceiver device 3 may further be configured to transmit said at least one characteristic parameter P_A_i detected by the sensor of vehicle A to the module 22 or to the transceiver 4 of obstacle B (if obstacle B is moving).

[0127] The characteristic parameters P_A_i detected by the sensors may be transmitted directly to the calculation module 22 .

[0128] In situations where the characteristic parameters P_A_i and / or P_B_i are available, the second calculation module 23 of the processing unit 20 calculates the collision probability (or impact trajectory) more accurately.

[0129] The processing unit 20 optionally comprises a filtering module configured to filter the signals SG_1, SG_2, P_A_i, P_B_i from one or more transceivers 3, 4 or magnitudes derived therefrom (e.g. angle, distance, etc.).

[0130] Examples of filtering are a median filter, an exponential flattening filter, or a Bayesian filter.

[0131] Advantageously, the processing unit 20 comprises a danger tracking and detection module configured to track the position, speed, orientation and acceleration of the external UWB tag and the host ground vehicle. Based on the current position of the external UWB tag, a prediction of its future position and the movement of the vehicle, it is possible to predict dangerous situations and potential collisions.

[0132] Optionally, each ground vehicle A and each obstacle B includes a memory module containing a unique identification code ID_A, ID_B of said vehicle A and said obstacle B. In this way, the identity of each obstacle and each ground vehicle present in the system 1 can be known and tracked.

[0133] Optionally, the alarm module 24 is also configured to activate and / or deactivate warnings of potential danger.

[0134] In particular, ground vehicle A may be, by way of non-limiting example, a forklift.

[0135] Moreover, obstacle B may be a fixed obstacle or a moving obstacle.

[0136] If obstacle B is moving, it may be, by way of non-limiting example, another ground vehicle or a person carrying a second transceiver device 4 .

[0137] In a non-limiting example of the present invention, as shown in FIG. 3, a transceiver 3 housed in a ground vehicle A comprises a UWB tag 3a and a number of AoA nodes 3b, 3c, 3d, 3e.

[0138] Preferably, the UWB tag 3a may be installed on the roof of the ground vehicle A, and each of the AoA nodes 3b, 3c, 3d, 3e may be installed respectively at the front, rear and two sides of the vehicle A. In this way, perfect directionality of the signals transmitted and received by the transceiver devices is obtained, improving the overall efficiency of the system 1.

[0139] In particular, the AoA UWB nodes 3b, 3c, 3d, 3e are transceiver devices capable of communicating with UWB tags (installed in the obstacle B or in a second vehicle and / or operator) using ultra-wideband (UWB) technology. The UWB AoA nodes 3b, 3c, 3d, 3e use Angle of Arrival (AoA) methods to determine the relative position of the UWB tag 3a with respect to the UWB AoA nodes 3b, 3c, 3d, 3e.

[0140] The UWB tag 3a is a transceiver device capable of communicating with UWB AoA nodes 3b, 3c, 3d, 3e using ultra-wideband (UWB) technology.

[0141] The AoA UWB tag 3a may include an extended IMU 30. The extended IMU 30 includes at least one of an accelerometer, a gyroscope, a magnetometer, a barometer, and a thermometer.

[0142] The UWB tag 3a may communicate its extended IMU 30 data to, and receive its relative position from, the UWB AoA nodes 3b, 3c, 3d, 3e.

[0143] During operation, the UWB tag 3a of vehicle A and each of the AoA UWB nodes 3b, 3c, 3d, 3e continuously detect the proximity of an obstacle B (e.g., a person working, another vehicle, or a structure) near the forklift transceiver device.

[0144] In this regard, the proximity of obstacle B to forklift A will typically include not only the relative distance of obstacle B from ground vehicle A, but also its relative orientation with respect to vehicle A.

[0145] The detection system may then typically include multiple sensors oriented or pointed in a known direction, whose collective signal may identify a position relative to the forklift or obstacle device on a two-dimensional and / or three-dimensional Cartesian grid.

[0146] In a second aspect of the present invention, a collision avoidance method for a ground vehicle operating in a work environment is provided, comprising the steps of: a) associating a first transceiver device 4 with an obstacle B, said first transceiver device 4 being configured to generate and transmit one or more radio signals SG_B_i, a first radio signal SG_B_1 carrying an obstacle identification code ID_1; b) associating a second transceiver device 3 with the ground vehicle A, said second transceiver device 3 being configured to generate and transmit one or more radio signals SG_A_i; c) transmitting said one or more radio signals SG_B_i from said obstacle B at predetermined time intervals; d) receiving, from the second transceiver device 3 associated with ground vehicle A, the first signal SG_B_1 having an obstacle identification code ID_1 transmitted by the first transceiver device 4 associated with obstacle B; e) determining the trajectories D_TRJ of the ground vehicles A and the obstacles B as a function of the signals SG_B_i, SG_A_i; f) determining the collision probability between ground vehicle A and obstacle B as a function of the trajectory D_TRJ of said ground vehicle A and obstacle B; g) generating a collision probability signal S_COLL between the ground vehicle A and the obstacle B in response to a high collision probability between the ground vehicle A and the obstacle B; h) transmitting the collision probability signal S_COLL.

[0147] Preferably, the trajectories of the ground vehicle A and the obstacle B identified in step e) are calculated in the following sub-steps: e1) calculating a relative distance D_REL between the ground vehicle A and the obstacle (B) based on radio signals SG_B_i, SG_A_i exchanged between the first transceiver device 4 and a second transceiver device 4 associated with the obstacle B; e2) calculating the relative angle A_REL between the ground vehicle A and the obstacle B in a given reference frame S_RIF.

[0148] Advantageously, the signals SG_1, SG_2 transmitted by the transceiver devices 3, 4 are ultra-wideband signals.

[0149] Alternatively, the first signal SG_A_i and the second signal SG_B_i transmitted by the second transceiver device 3 and the first transceiver device 4 are Bluetooth® signals, and the trajectory identified in step e) is calculated using the angle of departure method or the angle of arrival method.

[0150] The present invention achieves the following technical advantages: -For accurate relative positioning, use AoA techniques and measure distance (without which the position cannot be calculated accurately) to accurately calculate the vehicle's position relative to the tag, -This precise relative localization (accuracy is a critical success factor) is used to identify: - distinguish between situations where a potential collision may occur and situations where a potential collision may occur in a "general" system, but where it is instead known that no collision will occur with the subject system of the present application (e.g. passing / crossing between two machines side by side); -Identify trajectory calculations.

[0151] As can be easily understood by a person skilled in the art, the present invention makes it possible to overcome the drawbacks highlighted above with reference to the prior art.

[0152] In particular, the invention makes it possible to improve the safety of the means and the operators operating in working or open environments with potential collision risks, and also to allow a better safety management in the environment in which the ground vehicle operates.

[0153] It is clear that certain features have been described in connection with various embodiments of the present invention with illustrative and non-limiting intent. Obviously, those skilled in the art can make further modifications and variations to the present invention to meet fortuitous and specific needs. For example, technical features described in connection with embodiments of the present invention can be deduced therefrom and applied to other embodiments of the present invention. Such modifications and variations are further included within the scope of the present invention, as defined by the following claims.

Claims

1. A collision avoidance system (1) for a ground vehicle operating in a work environment, comprising: a first transceiver device (4) associated with an obstacle (B), configured to generate and transmit one or more radio signals (SG_B_i) at pre-established time intervals, the first radio signal (SG_B_1) carrying an obstacle identification code (ID_1); a second transceiver device (3) associated with a ground vehicle (A) configured to transmit one or more radio signals (SG_A_i) and to receive the one or more radio signals (SG_B_i) including the first radio signal (SG_B_1) carrying the obstacle identification code (ID_1), the first transceiver device (4) is adapted to directly receive the radio signals (SG_A_i) transmitted by the second transceiver device (3) associated with the ground vehicle (A), The collision avoidance system (1) comprises a processing unit (20) mounted on the ground vehicle (A) and configured to process collision data of the ground vehicle (A), the processing unit (20) comprising: a first calculation module (21) configured to determine a trajectory (D_TRJ) of said ground vehicle (A) and said obstacle (B) as a function of said radio signals (SG_B_i) and said radio signals (SG_A_i); a second calculation module (23) configured to determine a collision probability between the ground vehicle (A) and the obstacle (B) based on the trajectory (D_TRJ); a warning module (24) configured to generate and transmit a collision probability signal (S_COLL) between the ground vehicle (A) and the obstacle (B) in response to a high collision probability between the ground vehicle (A) and the obstacle (B), the obstacle (B) is a second ground vehicle; the message exchange initiated by the first radio signal (SG_B_1) includes a specific exchange in which the first radio signal (SG_B_1) includes a unique destination ID and only vehicles carrying that ID can respond, and a broadcast exchange in which the first radio signal (SG_B_1) does not include a specific destination ID and all vehicles within range can respond; A collision avoidance system (1), in which the specific exchange is only performed if there is at least one vehicle that responds, and only between the vehicle identified as the closest.

2. The first calculation module (21) a first calculation sub-module (21a) configured to calculate a relative distance (D_REL) between the ground vehicle (A) and the obstacle (B) based on the signal (SG_B_1) transmitted by the second transceiver device (4) associated with the obstacle (B); and a second sub-module (21b) configured to calculate a relative angle (A_REL) between said ground vehicle (A) and said obstacle (B) in a given reference system (S_RIF).

3. 3. The system (1) according to claim 2, wherein the signals transmitted by the first transceiver device (4) and the second transceiver device (3) are ultra-wideband signals.

4. the first calculation sub-module (21a) is configured to calculate the relative distance (D_REL) between the ground vehicle (A) and the obstacle (B) based on the power of the transmitted signal (SG_B_1); The system (1) according to claim 2 or 3, wherein the second sub-module (21b) is configured to calculate the relative angle (A_REL) between the ground vehicle (A) and the obstacle (B) in a given reference frame (S_RIF) using an angle of arrival or angle of departure approach with respect to the received signal (SG_B_1).

5. the ground vehicle (A) is equipped with a plurality of second transceiver devices (3); the first calculation sub-module (21a) is configured to calculate the relative distance (D_REL) between the ground vehicle (A) and the obstacle (B) based on a time difference of arrival of the signals (SG_B_1) received from the plurality of second transceiver devices (3); The system (1) according to claim 2 or 3, wherein the second sub-module (21b) is configured to calculate the relative angle (A_REL) between the ground vehicle (A) and the obstacle (B) in a given reference frame (S_RIF) using the time difference of arrival technique.

6. 2. The system (1) according to claim 1, wherein the obstacle (B) comprises a module configured to calculate a relative distance (D_REL_B) between the ground vehicle (A) and the obstacle (B) based on a periodic and ordered exchange of two messages (SG_B_1; SG_A_1).

7. The system (1) according to claim 6, wherein said obstacle (B) is configured to transmit in every message (SG_B_i) said last calculated relative distance (D_REL_B).

8. the processing unit (20) of the ground vehicle (A) determines a relative distance (D_REL) from the obstacle (B) by an ordered exchange of at least three signals (SG_B_1; SG_A_1; SG_B_2); The system (1) of claim 1 or 2, wherein the signal SG_B_2 includes an elapsed time (T_round_B) from the start of transmission of the signal (SG_B_1) to the start of reception of the signal (SG_A_1) and an estimated elapsed time (T_reply_B) from the start of reception of the signal (SG_A_1) to the start of transmission of the signal (SG_B_2).

9. 9. The system (1) according to claim 1 or any one of claims 3 to 8, wherein the signals transmitted by the first transceiver device (4) and the second transceiver device (3) are Bluetooth signals.

10. The system (1) according to any one of claims 1 to 9, wherein the warning module (24) transmits the collision probability signal (S_COLL) to a control module (5) of the ground vehicle (A) and / or to a warning device (6) configured to warn the driver of the vehicle (A) and / or persons in the vicinity of the vehicle (A) of a potentially dangerous situation.

11. The system (1) of claim 10, wherein the control module (5) of the vehicle (A) is configured to send a command signal (S_COM) to the controller (7) of the vehicle (A) so that the controller (7) can act on the vehicle (A) in the event of a risk of collision.

12. The system (1) according to claim 10 or 11, wherein the warning device (6) comprises at least one or more of the following: a user interface, an audible warning device, an optical warning device.

13. The system (1) according to any one of claims 1 to 12, wherein the first transceiver device (4) associated with the obstacle (B) is configured to transmit at least one characteristic parameter (P_B_i) of the motion of the obstacle (B), and the processing unit (20) comprises a calculation module (22) configured to calculate the motion (S_MOV) of the obstacle (B) as a function of the characteristic parameter (P_B_i).

14. The characteristic parameters (P_B_i) of the possible movements of the obstacle (B) are at least Type of obstacle (S_OBS), acceleration signal (S_ACC), Angular velocity signal (S_GYR), A signal for the angle relative to magnetic north (S_MAGN), Barometric pressure signal (S_BAR), 14. The system (1) of claim 13, further comprising one or more of: a temperature signal (S_TEMP).

15. The first transceiver device (4) associated with the obstacle (B) is operatively associated with an IMU (20), the IMU (20) comprising at least: accelerometer, Gyroscope, Magnetometer, Barometer, A system (1) according to any one of claims 1 to 14, comprising one or more of the following:

16. 16. The system (1) according to any one of claims 1 to 15, wherein the first transceiver device (4) associated with the obstacle (B) is configured to receive a relative distance from the second transceiver device (3) associated with the vehicle (A).

17. The system (1) according to any one of claims 1 to 16, wherein the processing unit (20) comprises a filtering module configured to filter the signals (SG_A_1; SG_B_2; P_B_i; P_A_i) coming from one or more transceivers (3; 4).

18. 1. A collision avoidance method for a ground vehicle operating in a work environment, comprising: a) associating a first transceiver device (4) with an obstacle (B), said first transceiver device (4) being configured to generate and transmit one or more radio signals (SG_B_i), a first radio signal (SG_B_1) carrying an obstacle identification code (ID_1); b) associating a second transceiver device (3) with a ground vehicle (A), said second transceiver device (3) being configured to generate and transmit one or more radio signals (SG_A_i); c) transmitting said one or more radio signals (SG_B_i) from said obstacle (B) at pre-established time intervals; d) receiving directly, on a part of the second transceiver device (3) associated with the ground vehicle (A), the first radio signal (SG_B_1) having the obstacle identification code (ID_1) transmitted by the first transceiver device (4) associated with the obstacle (B); e) determining the trajectory (D_TRJ) of said ground vehicle (A) and said obstacle (B) as a function of said radio signals (SG_B_i; SG_A_i); f) determining a collision probability between said ground vehicle (A) and said obstacle (B) as a function of said trajectory (D_TRJ) of said ground vehicle (A) and said obstacle (B); g) generating a collision probability signal (S_COLL) between the ground vehicle (A) and the obstacle (B) in response to a high collision probability between the ground vehicle (A) and the obstacle (B); h) transmitting said collision probability signal (S_COLL); said steps e) to h) are performed on said ground vehicle (A) and said obstacle (B) is a second ground vehicle; the message exchange initiated by the first radio signal (SG_B_1) includes a specific exchange in which the first radio signal (SG_B_1) includes a unique destination ID and only vehicles carrying that ID can respond, and a broadcast exchange in which the first radio signal (SG_B_1) does not include a specific destination ID and all vehicles within range can respond; A collision avoidance method, wherein the specific exchange is performed only if there is at least one vehicle that responds, and is performed only with the vehicle that is recognized as the closest.

19. The trajectory (D_TRJ) of the ground vehicle (A) and the obstacle (B) identified in step e) e1) calculating a relative distance (D_REL) between said ground vehicle (A) and said obstacle (B) based on radio signals (SG_B_i; SG_A_i) exchanged between said first transceiver device (4) and said second transceiver device (4) associated with said obstacle; e2) calculating a relative angle (A_REL) between said ground vehicle (A) and said obstacle (B) in a given reference system (S_RIF).

20. 20. The method according to claim 19, wherein the signals (SG_1; SG_2) transmitted by the first transceiver device (4) and the second transceiver device (3) are ultra-wideband signals.

21. 21. The method of any one of claims 18 to 20, wherein one or more steps are computer implemented.

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