Anti-collision system and method for ground vehicles

Abstract

A collision avoidance system (1) for a ground vehicle is described, comprising a first transceiver device (4) associated with an obstacle (B), configured to generate and transmit one or more wireless signals (SG_B_i) at a pre-established time interval, the first wireless signal (SG_B_1) carrying an obstacle identification code (ID_1); a second transceiver device (3) associated with the ground vehicle (A), configured to transmit one or more wireless signals (SG_A_i) and receive the one or more wireless signals (SG_B_i) including the first wireless signal (SG_B_1) carrying the obstacle identification code (ID_1); a processing unit (20) configured to process collision data of the vehicle (A), comprising: a first calculation module (21) configured to determine, from the wireless signals (SG_B_i) and (SG_A_i), a trajectory (D_TRJ) of the ground vehicle (A) and the obstacle (B); a second calculation module (23) configured to determine, based on the trajectory (D_TRJ), a collision probability between the ground vehicle (A) and the obstacle (B); an alert module (24) configured to generate and send a collision probability signal between the ground vehicle (A) and the obstacle (B) according to a high collision probability between the ground vehicle (A) and the obstacle (B). The invention further describes a corresponding method and computer program.

Description

[0001] DESCRIPTION TECHNICAL FIELD

[0002] The present invention relates to a collision prevention system and method for ground vehicles.

[0003] In particular, the present invention relates to a system and method for predicting and preventing collisions of forklifts operating indoors and outdoors. PRIOR ART

[0004] It is fundamental, in any industrial sector, to reduce and prevent accidents involving ground vehicles, in particular in work sites where workers are directly exposed to moving vehicles (traditional and autonomous), to potential obstacles, to stationary and self-propelled machines, presenting a potential risk to humans.

[0005] Self-propelled machines and vehicles cause many serious or very serious injuries, even deaths, in the event of a collision with a person in the work site.

[0006] The risk of collision between self-propelled vehicles and operators occurs, for example, in construction sites where earthmoving or transport machines are usually operated, in port areas, in warehouses, in storage areas, etc. Similar problems also usually occur in manufacturing plants, for example in foundries, paper mills, etc.

[0007] Active systems for the prevention of work accidents have been developed.

[0008] In the specific case of preventing collisions between people and vehicles or between vehicles and vehicles or between vehicles and fixed obstacles, active systems have been adopted using sensors installed on the vehicles, for example configured as readers of so-called RFID tags or transponders.

[0009] The operators wear at least one RFID tag, for example installed on a helmet, on a jacket or on other mandatory passive safety equipment. Thanks to the interaction between the sensor and the radio frequency identification tag, when the sensor installed on the vehicle detects the presence of a person within the range of the vehicle, the operator operating the self-propelled vehicle is given an alarm by a central unit. In addition, when the presence of a person within the range of the vehicle is detected, other safety measures can be activated, for example slowing down the vehicle speed. Similarly, fixed or mobile obstacles can be provided with RFID tags. Therefore, the use of RFID transponder technology for the active prevention of work accidents is known. This known technology provides a system comprising at least one sensor and one or more transponders or RFID tags, which are able to communicate with each other. The sensor or reader and the transponder or responding device each comprise two independent antennas.

[0010] The first antenna on the sensor and the first antenna on the transponder are respectively used to emit and receive signals (typically microwaves) having the function of "waking up" or activating the RFID transponder, which is normally in a quiescent state, also for energy saving purposes.

[0011] The transponder is activated when it enters the restricted range or control volume of the sensor.

[0012] The second antenna on the transponder or responding device and the corresponding second antenna on the sensor allow the transmission (typically in radio frequency) from the transponder to the sensor and / or vice versa on a channel different from the channel on which the transponder activation signal is emitted.

[0013] It is known that this technology is applied to the active prevention of work accidents, in particular to prevent collisions between ground operators and vehicles. At least one sensor (typically more than one) is installed on the vehicle, while the operator wears at least one transponder. When the operator enters the range of one of the sensors on the vehicle, the latter wakes up the transponder and emits an alarm.

[0014] The above-described system has proved to be a useful tool for the prevention of work accidents.

[0015] In the known system, one perceived problem is the possible signal interference, in particular in closed environments such as warehouses, factories or other work environments. In fact, many current navigation systems lose the signal when there are objects or interference patterns. This is a problem, especially in buildings, which are usually crowded with objects of various types.

[0016] However, there is still room for further improving the level of safety that can be achieved.

[0017] One of the purposes of some embodiments of the invention described herein is to improve the level of safety and ergonomics of active protection systems of this type.

[0018] Another purpose of the invention is to improve the accuracy by localizing false positives.

[0019] Another purpose of the invention is to provide an anti-collision system and method for ground vehicles operating in work environments, which is able to guarantee a high level of safety.

[0020] Another purpose of the invention is to provide an anti-collision system and method for ground vehicles operating in work environments, which is able to guarantee a high level of safety.

[0021] Another equally important purpose of the invention is to provide an anti-collision system and method for ground vehicles operating in work environments, which is highly reliable, easy to implement and easy to use.

[0022] Purpose of the invention

[0023] In a first aspect of the invention, the above-mentioned objective is achieved by a collision avoidance system for ground vehicles operating in a working environment according to the invention.

[0024] The present invention discloses advantageous aspects.

[0025] In a second aspect of the invention, the above-mentioned objective is achieved by a collision avoidance method for ground vehicles operating in a working environment according to the invention.

[0026] In a third aspect, the present invention describes a computer program according to the invention, which, when run on a computer, implements at least one or more steps of the method according to the second aspect of the invention.

[0027] In summary, the present invention provides the following technical effects:

[0028] Improve the safety of operators and ground vehicles operating in enclosed areas.

[0029] The above-described technical effects / advantages, as well as other technical effects / advantages of the present invention, will become more apparent from the following description of exemplary embodiments provided in an approximate and non-limiting manner with reference to the accompanying drawings. Brief description of the attached diagram

[0031] To better understand the present invention and its advantages, some non-limiting exemplary embodiments are described below with reference to the accompanying drawings, in which:

[0032] Figure 1 An example of the system of the present invention is shown, which is adapted to reduce the probability of collisions between potential obstacles and ground vehicles operating in the workplace.

[0033] Figure 2 yes Figure 1 A block diagram of the system.

[0034] Figure 3 A non-limiting example of a ground vehicle is shown;

[0035] Figure 4 The time allocation diagram of the tag in the time slot is shown;

[0036] Figure 5a , Figure 5b , Figure 5c An example of a method for identifying and tracking ground vehicles that are closest to a given label is shown;

[0037] Figure 6 An example of calculating the collision probability by calculating the trajectory is shown schematically.

[0038] Detailed description of a preferred embodiment of the present invention

[0039] It should be noted that, in the following description, identical or similar blocks, components or modules are denoted with the same number in the attached drawings, even if they are shown in different embodiments of the invention.

[0040] With reference to the attached drawings, in which Figure 2 In the block diagram of

[0041] The obstacle B can consist of stationary or moving objects, machines and / or personnel.

[0042] The obstacle B can also be a second ground vehicle, able to move with respect to the first vehicle A.

[0043] In particular, the ground vehicle can be a forklift or an autonomous ground vehicle.

[0044] In a first aspect, the present invention relates to an anti-collision system 1 for a ground vehicle, the system 1 comprising: a first transceiver device 4 associated with an obstacle B, the first transceiver device 4 being configured to generate and transmit one or more wireless signals SG_B_i at predetermined time intervals, i.e. periodically, the first wireless signal SG_B_1 carrying an obstacle identification code ID_1; a second transceiver device 3 associated with the ground vehicle A, the second transceiver device 3 being configured to generate and transmit one or more wireless signals SG_A_i and to receive the one or more wireless signals SG_B_i generated by the obstacle B, including the first wireless signal SG_B_1 carrying the obstacle identification code ID_1.

[0045] The wireless signal SG_A_1 generated by the second transceiver device 3 associated with the ground vehicle A carries an identification code ID_2 of the vehicle A.

[0046] The first transceiver device 4 is configured to receive the one or more wireless signals SG_A_i transmitted by the second transceiver device 3 associated with the ground vehicle A.

[0047] The anti-collision system 1 for a ground vehicle operating in a work environment further comprises a processing unit 20 configured to process collision data of the vehicle A. The processing unit 20 comprises:

[0048] a first calculation module 21 configured to determine, from the wireless signals SG_B_i and the one or more signals SG_A_i, a trajectory D_TRJ of the ground vehicle A and of the obstacle B;

[0049] a second calculation module 23 configured to determine a probability of collision between the ground vehicle A and the obstacle B on the basis of the trajectory D TRJ of the ground vehicle A and of the obstacle B;

[0050] an alarm module 24 configured to generate and send a probability of collision signal S COLL between the ground vehicle A and the obstacle B as a function of a high probability of collision between said ground vehicle A and the obstacle B.

[0051] In particular, advantageously a comparison module (not shown in the figures) is present, configured to compare the probability of collision signal S COLL between the ground vehicle A and the obstacle B received from the third calculation module 23 with a pre-established threshold value stored in the storage unit. In this case, the alarm module 24 is configured to generate and send the probability of collision 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.

[0052] In general, it should be noted that, in the present application, the processing unit 20 is considered to be divided into different functional modules (storage modules or operating modules) with the sole purpose of clearly and completely describing its functions.

[0053] Such a processing unit can comprise a single electronic device, suitably programmed to perform the described functions, and the different modules can correspond to hardware entities and / or conventional software as part of the programmed device.

[0054] Alternatively or additionally, the functions can be performed by a plurality of electronic devices, on which the above-mentioned functional modules can be distributed.

[0055] The processing unit 20 can also make use of one or more processors for executing the instructions contained in the memory modules.

[0056] If there are two or more ground vehicles and / or a plurality of obstacles, each will house at least one transceiver device 3, 4.

[0057] 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 on the basis of 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 on the basis of the signals SG B i received from the transceiver device 3.

[0058] For example, the reference system S RIF is a two-dimensional and / or three-dimensional Cartesian reference system integral with the vehicle A.

[0059] In a first positioning operating mode between the ground vehicle A and the obstacle B, only one message SG_B_1 is used and the processing unit 20 of the ground vehicle A calculates the relative distance D_REL to the obstacle B using the power of the received signals (UWB and Bluetooth).

[0060] The angle formed by the obstacle B with respect to the vehicle A when receiving the message SG_B_i is calculated by the vehicle A using the AoA technique with multiple antennas.

[0061] The angle formed by the vehicle A with respect to the obstacle B when receiving the message SG_B_i is calculated by the vehicle A using the AoD technique with multiple antennas.

[0062] In a second positioning operating mode between the ground vehicle A and the obstacle B, only two messages SG_B_1, SG_A_1 are used. With the signal SG_B_1, the obstacle B sends its identification code ID_1. If known, the obstacle B also sends the last calculated position of the obstacle B with respect to the vehicle A. With the signal SG_A_1, the vehicle sends to the obstacle B the time T_reply_A (estimated time elapsed between the beginning of the reception of the message SG_B_1 and the beginning of the transmission of the signal SG_A_1) which will be used to calculate the travel time and then the relative distance D_REL between the vehicle A and the obstacle B. For this calculation, the formula TOF = (t2-t1-T_reply_A) / 2 can be used.

[0063] The angle formed by the obstacle B with respect to the vehicle A when receiving the message SG_B_i is calculated by the vehicle A using the AoA technique with multiple antennas.

[0064] In a third positioning operating mode between the ground vehicle A and the obstacle B, three messages SG_B_1, SG_A_1 and SG_B_2 are used.

[0065] In particular, with the signal SG_B_1, the obstacle sends its identification code ID_1. With the signal SG_A_1, the vehicle A can send to the obstacle B the previously calculated position of the obstacle B.

[0066] Subsequently, obstacle B generates and transmits signal SG_B_2, which includes time T_round_B (the elapsed time from the start of transmitting SG_B_1 to the start of receiving SG_A_1) and time T_reply_B (the estimated elapsed time from the start of receiving SG_A_1 to the start of transmitting SG_B_2). This signal will be used to calculate the travel time. The relative angle A_REL formed by obstacle B relative to vehicle A is calculated using multi-antenna AoA technology upon receiving message SG_B_2. At the end of the three-message exchange, vehicle A's processing unit 20 calculates the relative distance D_REL of obstacle B using the processing time (round trip and reply) of obstacle B and vehicle A, as well as the arrival time of the final package. In this case, the calculation accuracy of D_REL and angle A_REL is high.

[0067] In the three positioning operation modes, the relative distance D_REL between ground vehicle A and obstacle B, and the angle of the tag of obstacle B relative to ground vehicle A, are calculated by using two or more antennas to receive the last message.

[0068] The collision avoidance method for ground vehicles of the present invention includes steps or phases for identifying and tracking obstacles or ground vehicles (associated with tags) that are closer to a given vehicle and therefore more likely to collide with it.

[0069] Specifically, UWB technology is used to perform the steps of identifying and tracking vehicles approaching the vehicle.

[0070] In particular, this method is based on the continuous exchange of messages between a tag and the vehicle closest to it.

[0071] As described above, the message exchange between a given tag and a vehicle allows the location of the tag relative to the vehicle to be determined.

[0072] The tag begins message exchange with the first initial request message (SG_B_1). Message exchange can be of two types:

[0073] 1. Identification Exchange (IE): The initial request message contains a unique destination ID, and only the vehicle holding that ID can respond;

[0074] 2. Broadcast Exchange (BE): The initial request message does not contain a specific destination ID, and all vehicles within range can respond.

[0075] like Figure 4 As shown, each tag is configured to divide the time into time slots numbered "Slot_1", "Slot_2", "Slot_3", ..., "Slot_N".

[0076] In each individual slot "Slot_i", the tag can perform one or more of the following steps: keep a memory of each vehicle with which it exchanged a message. In particular at least: the type of exchange performed, the spatial distance from the tag (computed or estimated) and the time offset (with respect to the beginning of the slot) at which the message exchange started. One implementation example to track this information is to store in memory a table, i.e. a "vehicle table". For each vehicle with which the tag exchanged a message, the table contains at least the following fields: vehicle ID (unique in the table), spatial distance from the tag (Euclidean or other), type of exchange performed, time offset. The table can contain N records, ordered by increasing distance value, and updated after each slot in which a message is exchanged is envisaged. A vehicle VA is considered closer to the tag of a vehicle VB if the distance value of VA is smaller than the distance value of VB. And the s (with s<=N) closest vehicles known by the tag are the first s vehicles contained in the vehicle table.

[0077] manage up to n_ie (greater than or equal to 1) IE message exchanges with (n_ie + n_be) different vehicles and up to n_be (greater than or equal to 1) BE message exchanges;

[0078] the exchange of messages can move its execution within a slot to avoid RF collisions;

[0079] BE messages are always performed;

[0080] IE messages are performed only if at least one vehicle responds from the previous slot;

[0081] At the end of the slot message exchange, the vehicle table is updated with the new information obtained as a result of the message exchange and reordered, then the target IDs are calculated for any subsequent IE message;

[0082] The next IE message will be addressed to the first n_ie vehicles that appear in the vehicle table;

[0083] If there is no response to a BE message, the tag can decide whether to perform the next BE message with a new time offset (with respect to the beginning of the slot). In addition, if the BE has been answered from a vehicle Az in the previous slot, the tag can decide to remove Az from the vehicle table;

[0084] If there is no response to an IE message from a vehicle Ay for a given number J of consecutive times, then: a) if there is no response from any BE message, only one BE message will be performed in the subsequent slot.

[0085] In addition, the vehicle Ay is removed from the vehicle table;

[0086] b) if one or more BE messages have been answered, then the vehicle Ay shall be removed from the vehicle table. At the end of the slot, after updating and reordering the vehicle table, it will be chosen for this IE whether to direct in the next slot the first vehicle Ax having a BE type exchange in the table.

[0087] The message exchange answered by a vehicle will keep its current offset (relative to the beginning of the slot) in the following slot.

[0088] In each individual slot "Slot_i", the vehicle A can perform one or more of the following steps:

[0089] Save the current slot number of each tag with which it communicates. The slot number of a tag can be sent by the tag itself or the vehicle can estimate it by knowing the duration of the slot and the arrival time of the message from the tag;

[0090] There is only one message exchange with a predetermined tag;

[0091] It is possible to respond immediately to the broadcast exchange or to wait a random time between 0 and time t_Wait.

[0092] The random time can be preconfigured or dynamically adjusted.

[0093] If the received power of the first message SG_B_1 is less than a predetermined threshold, the tag can not respond;

[0094] It is possible to respond to the broadcast exchange from the same tag every slot or every n1 (n1 = 1, 2, 3,...) slots. This can be preconfigured or dynamically adjusted.

[0095] This method is efficient both from the energy point of view and for the occupation of the UWB channel. This is because the tag does not communicate with all the vehicles present, but only tries to communicate with the vehicles closest in space, and therefore with the most relevant vehicles, in order to detect possible collisions.

[0096] In addition, this method does not require the tag to know a priori which are the possible vehicles it can come into contact with (i.e. their identifiers).

[0097] This means that the tag does not have to reconfigure every time.

[0098] Finally, this method ensures that the obstacle (tag) is detected by the n_ie+ n_be*n1 closest vehicles.

[0099] The exchange of messages from the tag to the IE messages of the same vehicle will be exchanged with a frequency of 1 / T_Slot (where T_Slot is the duration of a time slot in seconds, typically T_Slot = 0.1 s). The exchange of messages from the tag to the BE messages of the same vehicle will be exchanged with a frequency of 1 / (n_1*T_Slot).

[0100] In practice, a good choice is n_ie = n_be = 1 and n1 = 2.

[0101] Figure 5a , Figure 5b and Figure 5c shows an execution example of the method according to the present application. In Figure 5c , it is assumed that the parameters n1, n_ie and n_be are all 1.

[0102] Figure 5a shows the distance of the first VA and the second vehicle VB from the tag.

[0103] Alternatively, Figure 5b shows the distance of the two vehicles VA and VB from the tag at the 300 ms instant of Figure 5c .

[0104] These figures show two vehicles (VA and VB) in the vicinity of a given tag.

[0105] Until time 300 ms, the first vehicle VA is closer to the tag than the second vehicle VB Figure 5a .

[0106] At time 300 ms, the first vehicle VA leaves and the second vehicle VB approaches the closest tag Figure 5b to the first vehicle VA.

[0107] In the first time slot (Slot_1), the tag performs the exchange of messages only in BE mode.

[0108] Since the first vehicle VA responds by sending its ID to the tag, at time slot_2 the tag performs an IE and another BE with the first vehicle VA to search for the presence of another vehicle. Since the second vehicle VB also responds to the BE, the relative offset of the two messages will be maintained.

[0109] At time slot_3, the sequence of message exchange is repeated exactly because the first vehicle VA is closer to the tag with respect to the second vehicle VB.

[0110] Also at time slot_4, the sequence of message exchange is repeated in the same way as at time slot_2 and time slot_3.

[0111] At the end of time slot_4, the tag realizes that the second vehicle VB is now the closest, while the first vehicle VA has left.

[0112] In the following time slot_5, the system will perform the IE with the second vehicle VB.

[0113] Figure 6 An example of the computation of the probability of collision by computing the trajectory is shown. In this figure, ri represents the position of the obstacle (tag) in time slot_i, vi represents the speed of the obstacle in time slot_i.

[0114] In Figure 6 , the current time slot is the number 3 (slot_3).

[0115] The history trajectory is the set r0, v0, r1, v1, r2, v2, r3, v3.

[0116] The predicted trajectory is the set r3, v3, r_impatto, v_impatto, r4, v4.

[0117] Time to impact = impact distance / |v3|, where |v3| represents the intensity of the vector v3.

[0118] The vehicle keeps the history trajectory of the obstacle, which is given by the set of position and speed of the concerned vehicle for each time slot up to the current time slot.

[0119] From the history trajectory of the obstacle, the vehicle computes the predicted trajectory for the next N time slots. From the predicted trajectory of the vehicle and the geometric information (footprint), the vehicle computes the point of possible impact with the obstacle together with the relative time to impact.

[0120] Finally, the probability of collision is defined by assigning a collision probability value to each value of "time to impact". For example, we can say that when "time to impact" is less than 2 seconds, then the probability of collision is equal to 1.

[0121] If "time to impact" is greater than 2 seconds and less than 4 seconds, then the probability of collision is 0.8, and so on.

[0122] For example, the predicted trajectory can be computed by assuming that the vehicle continues to move from its current position with the last computed speed.

[0123] The described method is efficient both from the energy point of view and for the occupation of the UWB channel.

[0124] This is because in each time slot, the tag performs at most (n ie + n be) message exchanges to detect a collision with a possible obstacle. This is possible because the tag only tries to communicate with the spatially closest obstacle.

[0125] In addition, the method does not require the tag to know a priori which possible vehicles it can come into contact with (i.e. their identifiers). This means that the tag does not have to reconfigure each time.

[0126] The signals SG_1, SG_2 generated and transmitted by each transceiver device 3, 4 present in the system 1 are advantageously signals of the ultra-wideband (UWB) type.

[0127] A signal of the ultra-wideband type is defined as a radio frequency (RF) signal occupying a spectral portion greater than 20% of the central carrier, or having a bandwidth greater than 500 MHz. UWB is a communication channel that covers a large portion of the spectrum. This allows UWB transmitters to transmit large amounts of data while consuming little transmission energy. UWB can be used to determine positioning by using the time difference of arrival (TDOA) of the RF signals to obtain the distance between the reference point and the obstacle, or using a two-way ranging technique (TWR) to measure the distance accurately.

[0128] Alternatively, the signals transmitted by the transceiver devices 3 and 4 are Bluetooth signals.

[0129] To mitigate the occupation of the UWB band and thus reduce the likelihood of collisions in the channel, particularly in the presence of many tags in the vicinity of a vehicle, additional transceivers can be introduced on the tags and on the vehicles working in a different RF band (e.g. BLE or RFID).

[0130] We will refer to this band as the support RF channel.

[0131] In addition, these transceivers are connected to the UWB unit, so that they can convey information (e.g. the ignition signal).

[0132] In general, the tag tries to detect the presence of a vehicle in its vicinity by exchanging messages in the support channel.

[0133] If a vehicle is detected, a less accurate estimate of its distance is calculated. This estimate is usually calculated using the received signal strength. If this estimate is less than a specified threshold, the tag activates the UWB system operation for a more accurate positioning and suspends the support transceiver.

[0134] When the tag detects that no vehicle is closer than a specified threshold, it suspends the UWB system and activates the support transceiver.

[0135] Here are the two possible options to start the support message exchange between the tag and the vehicle: 1. The tag periodically transmits a message in the support channel. The vehicle, upon receiving this message, responds with a message in the support channel.

[0136] 1) The vehicle is always listening for messages in the support band and responds to any message sent by the tag.

[0137] The tag periodically exchanges messages in the support channel. BLE technology will be preferred for this option.

[0138] 2) The vehicle periodically sends messages in the support channel that can be received by the tag through continuous or periodic listening of the support channel. RFID technology will be preferred for this option.

[0139] In the event of a probability of collision danger, the alarm module 24 sends a collision probability signal S COLL to the control module 5 of the ground vehicle A. In particular, the probability of collision danger occurs if the collision probability S COLL exceeds a threshold value that can be pre-established and stored in a storage unit present in the system 1, above which the alarm module 24 sends the collision probability signal S COLL to the control module 5.

[0140] In this case, the control module 5 of the vehicle A is configured to send in turn to the controller 7 of the vehicle A a suitable command signal S COM, so that the controller 7 is able to intervene on the vehicle A in the event of a collision risk.

[0141] Possible examples of vehicle intervention modes include the emergency activation of the vehicle braking system, the vehicle deceleration, the activation of the vehicle steering members to avoid a possible impact with the obstacle B.

[0142] In this way, by means of the control module 5, the processing unit 20 is able to act on the braking system and / or on the engine system and / or on the direction of the vehicle A, as a function of the collision probability signal S COLL received from the alarm module 24.

[0143] The alarm module 24 is also configured to send the collision probability signal S COLL to an alarm device 6 configured to alert the driver of the vehicle A and / or the people in the vicinity of the vehicle A of a potentially dangerous situation.

[0144] Some non-limiting examples of possible control signals S COM include one or more actions of at least vehicle deceleration, vehicle braking, vehicle B return to normal operation, change of direction of the vehicle A with respect to the direction of impact with the obstacle B in the collision movement.

[0145] Some non-limiting examples of possible alarm devices 6 include one or more of at least one user interface, an audible warning device and / or an optical warning device.

[0146] Advantageously, the transceiver 3 present on the ground vehicle A determines the relative position between the two transceivers 3 and 4 using the angle of arrival and / or the angle of departure and / or the time difference of arrival (TDOA) method.

[0147] Advantageously, the first transceiver device 4 associated with the obstacle B is configured to transmit at least one characteristic parameter P_B_i of the movement of the obstacle B. In this case, the processing unit 20 comprises a calculation module 22 configured to calculate the movement of the 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 the obstacle B can be present on the obstacle B (not shown in the figures).

[0148] The optional characteristic parameters P_B_i, P_A_i of the possible movement of the obstacle B transmitted by the transmitters 3 or 4 comprise one or more of at least the acceleration signal S_ACC, the angular velocity signal S_GYR (i.e. the angle in time units spaced apart on the respective axis), the signal S_MAGN relative to the angle with respect to the magnetic north pole, the barometric pressure signal S_BAR, the signal relating to the type of obstacle (for example, person, stationary object, moving object, etc.) and / or the temperature signal S_TEMP and / or the time signal (for example, the number of time slots or the time since the transmitter 3 associated with the obstacle was switched on).

[0149] Advantageously, the transceiver 4 associated with the obstacle B is operatively associated with an IMU (Inertial Measurement Unit) 30 comprising one or more of at least an accelerometer, a gyroscope, a magnetometer, a barometer and / or a thermometer.

[0150] Advantageously, the first transceiver device 4 associated with the obstacle B is configured to receive the relative distance D_REL of the second transceiver device 3 associated with the vehicle A.

[0151] In this way, for example, in the case of movement of the ground vehicle, and with the possibility of avoiding a collision with the ground vehicle A, the obstacle B will also be able to evaluate the probability of a collision with the vehicle A and avoid a possible collision.

[0152] Advantageously, the second transceiver device 3 associated with the ground vehicle A can be configured to receive at least one characteristic parameter P_A_i of the movement of the vehicle A (detected by appropriate sensors present on the ground vehicle or installed specifically on the vehicle), such as the speed, the acceleration, the steering angle, etc.

[0153] The second transceiver device 3 can be further configured to transmit said at least one characteristic parameter P_A_i detected by the sensors of the vehicle A to the module 22 or to the transceiver 4 of the obstacle B (in the case where the obstacle B is moving).

[0154] The characteristic parameters P_A_i detected by the sensors can also be sent directly to the calculation module 22.

[0155] In the case where the characteristic parameters P_A_i and / or P_B_i are available, a second calculation module 23 of the processing unit 20 will calculate the collision probability (or impact trajectory) more precisely.

[0156] The processing unit 20 optionally comprises a filtering module configured to filter the signals SG_1, SG_2, P_A_i, P_B_i or the amplitudes (for example angles, distances, etc.) derived therefrom coming from one or more transceivers 3, 4.

[0157] Examples of filtering are median filtering, exponential flattening or Bayesian filtering.

[0158] Advantageously, the processing unit 20 comprises a hazard tracking and detection module configured to track the positioning, speed, orientation and acceleration of the external UWB tags and of the host ground vehicle. Based on the current position of the external UWB tags, the prediction of their future position and the movement of the vehicle, it is possible to predict hazardous situations and potential collisions.

[0159] Optionally, each ground vehicle A and each obstacle B comprises a storage module comprising a unique identification code ID_A, ID_B of said vehicle A and of said obstacle B. In this way, it is possible to know and track the identity of each obstacle and each ground vehicle present in the system 1.

[0160] Optionally, the alert module 24 is also configured to activate and / or stop the alert of potential hazards.

[0161] In particular, as a non-limiting example, the ground vehicle A can be a forklift.

[0162] In addition, the obstacle B can be a fixed obstacle or a moving obstacle.

[0163] As a non-limiting example, if the obstacle B is moving, it can be another ground vehicle or a person wearing a first transceiver device 4.

[0164] In a non-limiting example of the application, as shown in Figure 3 The transceiver 3 housed on the ground vehicle A comprises a UWB tag 3a and a plurality of AoA nodes 3b, 3c, 3d, 3e.

[0165] Preferably, the UWB tag 3a can be mounted on the roof of the ground vehicle A and each AoA node 3b, 3c, 3d, 3e can be mounted on the front, rear and both sides of the vehicle A, respectively. In this way, the complete directionality of the signals transmitted and received by the transceiver devices is obtained, improving the overall efficiency of the system 1.

[0166] In particular, the AoA UWB nodes 3b, 3c, 3d, 3e are transceiver devices capable of communicating with a UWB tag (mounted on an obstacle B or on a second vehicle and / or operator) using Ultra-Wide Band (UWB) technology. The UWB AoA nodes 3b, 3c, 3d, 3e use the Angle of Arrival (AoA) method to determine the relative position of the UWB tag 3a with respect to the UWB AoA nodes 3b, 3c, 3d, 3e.

[0167] The UWB tag 3a is a transceiver device capable of communicating with the UWB AoA nodes 3b, 3c, 3d, 3e using Ultra-Wide Band (UWB) technology.

[0168] The AoA UWB tag 3a can comprise an extended IMU 30. The extended IMU 30 contains at least one of the following elements: accelerometer, gyroscope, magnetometer, barometer, thermometer.

[0169] The UWB tag 3a can transmit the data of its extended IMU 30 to the UWB AoA nodes 3b, 3c, 3d, 3e and can receive its relative position from the UWB AoA nodes 3b, 3c, 3d, 3e.

[0170] During operation, each AoA UWB node 3b, 3c, 3d, 3e and the UWB tag 3a on the vehicle A continuously detect the proximity of any obstacle B (e.g. a person at work, another vehicle or a structure) located in the vicinity of the forklift transceiver device.

[0171] In this regard, the proximity of the obstacle B to the forklift A typically includes not only the relative distance of the obstacle B to the ground vehicle A, but also the direction with respect to the vehicle A.

[0172] The detection system can then typically comprise a plurality of sensors oriented or directed in a known direction and the collection of their signals can determine the position with respect to the forklift or obstacle device on a two- and / or three-dimensional Cartesian grid.

[0173] In a second aspect of the application, a collision avoidance method for a ground vehicle operating in a work environment is provided, the method comprising the steps of:

[0174] a) associating a first transceiver device 4 with the obstacle B, said first transceiver device 4 being configured to generate and transmit one or more wireless signals SG_B_i, the first wireless signal SG_B_1 carrying an obstacle identification code ID_1;

[0175] 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 wireless signals SG_A_i;

[0176] c) transmitting said one or more wireless signals SG_B_i from said obstacle B at predetermined time intervals;

[0177] d) receiving, from said second transceiver device 3 associated with the ground vehicle A, said first wireless signal SG_B_1 having the obstacle identification code ID_1 transmitted by the first transceiver device 4 associated with the obstacle B;

[0178] e) determining a trajectory D_TRJ of the ground vehicle A and the obstacle B from the signals SG_B_i, SG_A_i;

[0179] f) determining a collision probability between said ground vehicle A and the obstacle B from the trajectory D_TRJ of the ground vehicle A and the obstacle B;

[0180] g) generating a collision probability signal S_COLL between the ground vehicle A and the obstacle B from a high collision probability between said ground vehicle A and the obstacle B.

[0181] h) sending said collision probability signal S_COLL.

[0182] Preferably, the trajectory of the ground vehicle A and the obstacle B determined in step e) is calculated by the following sub-steps:

[0183] e1) calculating a relative distance D_REL between the ground vehicle A and the obstacle (B) based on the wireless signals SG_B_i, SG_A_i exchanged between the first transceiver device 4 associated with the obstacle B and the second transceiver device 3;

[0184] e2) calculating a relative angle A_REL between the ground vehicle A and the obstacle B in a given reference system S_RIF.

[0185] Advantageously, the signals SG_1, SG_2 transmitted by the transceiver devices 3, 4 are ultra-wideband signals.

[0186] Alternatively, the first and second signals SG_A_i, SG_B_i transmitted by said first and second transceiver devices 4, 3 are Bluetooth signals and the trajectory determined in step e) is calculated with an angle of departure method or an angle of arrival method.

[0187] This invention achieves the following technical effects:

[0188] AoA technology is used and distance is measured (otherwise the position cannot be accurately calculated) to accurately calculate the vehicle's position relative to the tag for precise relative positioning;

[0189] This precise relative position (precision is an important enabling factor) is used to distinguish:

[0190] Between situations where potential collisions may exist and situations where collisions are known not to occur for "general" systems rather than for system objects of the application (e.g., two machines passing side by / intersecting);

[0191] Calculation of the trajectory.

[0192] As will be readily understood by those skilled in the art, the present invention allows for overcoming the disadvantages highlighted above regarding the prior art.

[0193] In particular, this invention allows for improved safety for operators and equipment operating in work environments or open environments with potential collision risks. It also allows for better safety management in environments with ground vehicles.

[0194] It is obvious that the specific features are described in conjunction with different embodiments of the invention with an exemplary and non-limiting intent. It is apparent that those skilled in the art can make further modifications and variations to the invention to meet possible and specific requirements. For example, the technical features described with respect to embodiments of the invention can be extrapolated and applied to other embodiments of the invention. Furthermore, such modifications and variations are included within the scope of the invention as defined by the appended claims.

Claims

1. An anti-collision system (1) for a ground vehicle, comprising: a first transceiver device (4) associated with an obstacle (B), said first transceiver device (4) being configured to generate and transmit one or more wireless signals (SG_B_i) at a pre-established time interval, a first wireless signal (SG_B_1) carrying an obstacle identification code (ID_1); a second transceiver device (3) associated with a ground vehicle (A), said second transceiver device (3) being configured to transmit one or more wireless signals (SG_A_i) and to receive said one or more wireless signals (SG_B_i) including said first wireless signal (SG_B_1) carrying said obstacle identification code (ID_1); said first transceiver device (4) being configured to directly receive said signals (SG_A_i) transmitted by said second transceiver device (3) associated with said ground vehicle (A); a processing unit (20) configured to process collision data of said vehicle (A), said processing unit (20) comprising: a first calculation module (21) configured to determine a trajectory (D_TRJ) of said ground vehicle (A) and of said obstacle (B) from said wireless signals (SG_B_i) and from said wireless signals (SG_A_i); a second calculation module (23) configured to determine a collision probability between said ground vehicle (A) and said obstacle (B) based on said trajectory (D_TRJ); an alert module (24) configured to generate and send a collision probability signal (S_COLL) between said ground vehicle (A) and said obstacle (B) according to a high collision probability between said ground vehicle (A) and said obstacle (B), wherein said processing unit (20) is associated with said ground vehicle (A); said system further comprising a tag associated with said obstacle (B), wherein said tag is configured to enable different types of message exchange with different vehicles: a first type based on an initial request message containing a unique destination ID, wherein only vehicles in possession of said ID can respond; and a second type based on an initial request message not containing a specific destination ID, directed to vehicles within a range, wherein any vehicle within said range can respond.

2. The system (1) according to claim 1, wherein said first calculation module (21) comprising: a first calculation sub-module (21a) configured to calculate a relative distance (D_REL) between said ground vehicle (A) and said obstacle (B) based on a signal (SG_B_1) transmitted by a first transceiver device (4) associated with said 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. The system (1) according to claim 2, wherein The signals transmitted by the first transceiver device (4) and by the second transceiver device (3) are ultra-wideband signals.

4. The system (1) according to claim 2 or 3, wherein 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), and 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 system (S_RIF) using angle of arrival or angle of departure techniques on the received signal (SG_B_1).

5. The system (1) according to claim 2 or 3, wherein The ground vehicle (A) comprises 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 the difference in time of arrival of the signals (SG_B_1) received from the plurality of second transceiver devices (3), and 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 system (S_RIF) using time difference of arrival techniques.

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

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

8. The system (1) according to claim 1, wherein, The processing unit (20) of the ground vehicle (A) determines the relative distance (D_REL) from the obstacle (B) through the ordered exchange of at least three signals (SG_B_1, SG_A_1, SG_B_2), wherein: The signal (SG_B_2) comprises the time elapsed between the start of the transmission of the signal (SG_B_1) and the start of the reception of the signal (SG_A_1) (t_round_B) and the estimated time elapsed between the start of the reception of the signal (SG_A_1) and the start of the transmission of the signal (SG_B_2) (t_reply_B).

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

10. The system (1) according to any one of the preceding claims 1 to 8, wherein, The alarm module (24) sends the collision probability signal (S_COLL) to a control module (5) of the ground vehicle (A) and / or to an alarm device (6) configured to alert the driver of the vehicle (A) and / or a person in the vicinity of the vehicle (A) of a potential dangerous situation.

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

12. The system (1) according to claim 10, wherein The alarm device (6) comprises at least one or more of: a user interface, a sound warning device; Optical warning device.

13. The system (1) according to any one of the preceding claims 1 to 8, 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 movement of the obstacle (B) and the processing unit (20) comprises a calculation module (22) configured to calculate the movement (S_MOV) of the obstacle (B) as a function of the characteristic parameter (P_B_i).

14. The system (1) according to claim 13, wherein The characteristic parameter (P_B_i) of the possible movement of the obstacle (B) comprises at least one or more of the following: a type of obstacle (S_OBS); an acceleration signal (S_ACC); an angular velocity signal (S_GYR); a signal relative to the angle with respect to the magnetic north pole (S_MAGN); an atmospheric pressure signal (S_BAR); a temperature signal (S_TEMP).

15. The system (1) according to any one of the preceding claims 1 to 8, wherein, The first transceiver device (4) associated with the obstacle (B) is operatively associated with an IMU (20) comprising at least one or more of the following: an accelerometer; a gyroscope; a magnetometer; a barometer; a thermometer.

16. The system (1) according to any one of the preceding claims 1 to 8, wherein The first transceiver device (4) associated with the obstacle (B) is configured to receive the relative position from the second transceiver device (3) associated with the vehicle (A).

17. The system (1) according to any one of the preceding claims 1 to 8, 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 of the first transceiver devices (4) and / or the second transceiver device (3).

18. A collision avoidance method for a ground vehicle operating in a work environment, comprising the following steps: a) associating a first transceiver device (4) with an obstacle (B), the first transceiver device (4) being configured to generate and transmit one or more wireless signals (SG_B_i), a first wireless signal (SG_B_1) carrying an obstacle identification code (ID_1); b) associating a second transceiver device (3) with a ground vehicle (A), the second transceiver device (3) being configured to generate and transmit one or more wireless signals (SG_A_i); c) transmitting the one or more wireless signals (SG_B_i) from the obstacle (B) at a pre-established time interval; d) the second transceiver device (3) receiving the first wireless signal (SG_B_1) with the obstacle identification code (ID_1); e) determining the trajectories (D_TRJ) of the ground vehicle (A) and the obstacle (B) as a function of the signals (SG_B_i, SG_A_i); f) determining the probability of collision between the ground vehicle (A) and the obstacle (B) as a function of the trajectories (D_TRJ) of the ground vehicle (A) and the obstacle (B); g) generating a collision probability signal (S_COLL) between the ground vehicle (A) and the obstacle (B) as a function of a high probability of collision between the ground vehicle (A) and the obstacle (B); h) transmitting the collision probability signal (S_COLL); i) the following different types of message exchange with different vehicles: a first type is based on an initial request message containing a unique destination ID, where only the vehicle holding said ID can respond; and a second type is based on an initial request message not containing a specific destination ID, directed to vehicles within a range, where any vehicle within said range can respond.

19. The method of claim 18, wherein, The trajectory (D_TRJ) of the ground vehicle (A) and of the obstacle (B) determined in step e) is calculated through the following sub-steps: e1) calculating the relative distance (D_REL) between the ground vehicle (A) and the obstacle (B) based on the wireless signals (SG_B_i, SG_A_i) exchanged between the second transceiver device (3) and the first 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).

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

21. The method according to any of the preceding claims 18 to 20, wherein, One or more steps are implemented by a computer.

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