Unmanned vessel and method for operating remotely controlled vessel

Abstract

The invention relates to an unmanned vehicle comprising a frame (12), a power unit (14) connected to the frame (12) for propulsion of the vehicle (10), an explosive charge (16) arranged to be carried by the vehicle (10), a power source (18), and a trigger (20) connected to the explosive charge (16), between the power source (18) and the explosive charge (16), for triggering the explosive charge (16). Further, the vehicle (10) comprises a first safety interlock (22) and a remote controlled second safety interlock (24) connected between the power source (18) and the explosive charge (16), as well as a mechanical binding means (30), preferably a cord, whose one end (32) is connected to the mechanical safety interlock (22) and whose other end (34) is connected to a solid object (38) at the launching point (36) of the vehicle (10), wherein said binding means (30) releases the first safety interlock (22) when the vehicle (10) moves further from the launching point (36). The second safety interlock (24) comprises a receiver (42) for receiving a second control signal via remote control by communication means (28). Further, the vehicle comprises a control unit (26) for controlling the vehicle (10), and a third safety interlock (40), as well as communication means (28) for controlling the vehicle (10) and for operating the remote controlled second safety interlock (24) via remote control. The control unit (26) is arranged to control the third safety interlock (40) on the basis of a selected criterion. The invention also relates to a method for operating a remote controlled vehicle.

Description

[0001] UNMANNED VESSEL AND METHOD FOR OPERATING REMOTELY CONTROLLED VESSEL

[0002] Field of the invention

[0003] The invention relates to an unmanned vehicle and a method for operating an unmanned vehicle .

[0004] Background of the invention

[0005] Remote controlled unmanned vehicles can be used for many purposes , including the transportation of various explosive charges to a target . When handling explosives , one should take into account the safety of the operator of the vehicle upon launching the vehicle by providing the explosive charge with safety interlocking to avoid unintentional explosions .

[0006] From the state of art , document US 9 , 410 , 783 Bl is known which discloses an unmanned remote controlled vehicle , in which the operator releases a first safety interlock by removing a pull pin before the launch of the vehicle . The vehicle also comprises a remote controlled second safety interlock, whereby the explosive charge is secured by the first and second safety interlocks . However, this kind of a solution involves the problem that after the first interlock is released by the operator removing the pull pin from the vehicle , the vehicle is still very close to the operator, and damage to its electronics may in some cases cause firing of the explosive charge and accidental death or serious inj ury of the operator .

[0007] Brief summary of the invention

[0008] The aim of the invention is to provide a vehicle which is safer than unmanned vehicles of prior art . The characteristic features of the vehicle according to the invention are disclosed in the appended claim 1 . The aim of the invention is also to provide a method which is safer than methods of prior art for operating a remote controlled vehicle . The characteristic features of the method according to the invention are disclosed in the appended claim 12 .

[0009] In an aspect , the unmanned vehicle comprises a frame , a power unit connected to the frame for propulsion of the vehicle , means for fitting an explosive charge to be carried by the vehicle , means for connecting a power source to the vehicle for forming an electric circuit , means for connecting a trigger between the power source and the explosive charge in the circuit for triggering the explosive charge , a first safety interlock and a second safety interlock between the power source and the explosive charge in said electric circuit , a control unit for controlling the vehicle , and communication means for steering the vehicle . Said second safety interlock is a manual switch, or said second safety interlock is remote controlled and comprises a receiver for receiving a second control signal via remote control from the operator using communication means . The vehicle further comprises a mechanical binding means whose one end is to be releasably connected to said vehicle and whose second end is to be connected to a solid obj ect at the point of launching the vehicle , wherein said binding means is arranged to release the first safety interlock when the vehicle moves further from the launching point , beyond the reach of the binding means ; and a third safety interlock which is arranged to be controlled by said control unit according to a selected criterion, wherein said first safety interlock, second safety interlock and third safety interlock are configured to control an electric circuit , wherein said second safety interlock and third safety interlock are arranged on di f ferent sides of the electric circuit with respect to said trigger, one upstream and the other downstream o f the trigger, and the first safety interlock is arranged on the same side of the electric circuit as the third safety interlock, wherein when the electric circuit is open, either the f irst safety interlock or the third safety interlock on the opposite side of the electric circuit is on, and a trigger command received by a manual switch or a launching command received via remote control by using communication means causes triggering of the explosive charge when the circuit is closed, when the second safety interlock on the first side of the circuit is released, and both the first safety interlock and the third safety interlock 40 on the second side of the circuit are released .

[0010] In another aspect , the unmanned vehicle comprises a frame , a power unit connected to the frame for propulsion of the vehicle , an explosive charge fitted to be carried by the vehicle , a power source , and a trigger connected to the explosive charge and arranged between the power source and the explosive charge , for triggering the explosive charge . Further, the vehicle comprises a first safety interlock and a remote controlled second safety interlock connected between the power source and the explosive charge , as well as a mechanical binding means , preferably a cord, whose one end is connected to the mechanical safety interlock and whose other end is connected to a solid obj ect at the launching point of the vehicle , wherein said binding means releases the first safety interlock when the vehicle moves further from the launching point . The second safety interlock comprises a receiver for receiving a second control signal via remote control by communication means . Further, the vehicle comprises an automatic control unit for controlling the vehicle , and a third safety interlock and communication means for operating the vehicle and the trigger and the remote controlled second safety interlock via remote control . The automatic control unit is configured to control the third safety interlock on the basis of a selected criterion . In an aspect , a method is provided for operating an unmanned vehicle according to an aspect . The method comprises the following steps : equipping the vehicle with an explosive charge ; starting the control unit of the vehicle for controlling the vehicle ( 10 ) ; releasing the first safety interlock; releasing the second safety interlock; triggering the explosive charge ; wherein for releasing the first safety interlock, the first safety interlock of the vehicle i s fastened to a solid obj ect by a mechanical binding means , and the first safety interlock is released by steering the vehicle beyond the reach of the binding means ; and the method further comprises : releasing the second safety interlock manually by remote control or by a manual switch, and releasing the third safety interlock by means of the control unit when a selected criterion is met .

[0011] In this context , the trigger refers more broadly to a device which causes either firing of the explosive charge or alternatively releasing of the explosive charge , that is , its launch from the vehicle towards a target where it will explode .

[0012] In the vehicle according to the invention, the mechanical binding means releases the first safety interlock first after the vehicle has moved to a safe distance from the operator . In this context , the safe distance will depend on the type of the vehicle in question . In the case of an aerial vehicle , the first safety interlock is released suf ficiently close to the ground so that a possible triggering of the explosive charge caused by a catastrophic failure after releasing the first safety interlock would not involve a risk to the operator . In the case of a vehicle moving in water, for example , the safe distance may be di f ferent . On the other hand, the third safety interlock which is controlled by the automatic control unit is autonomous in relation to the second safety interlock operated by the operator, to secure that the explosive charge will not be triggered accidentally even in case of failure of one of the safety interlocks .

[0013] Preferably, the third safety interlock is a programmable unit configured to be released according to a selected criterion and to enable the operation of the trigger . Consequently, the third safety interlock is autonomous in relation to the first and second safety interlocks .

[0014] In an embodiment , the third safety interlock is a programmable element of the automatic control unit . In this way, the third safety interlock is easy to implement .

[0015] Alternatively, the third safety interlock may also be a programmable unit separate from the automatic control unit .

[0016] Preferably, the automatic control unit is configured to examine whether the criterion selected for releasing the third safety interlock is met , and to give the third safety interlock a release command when the criterion is met .

[0017] The trigger and the third safety interlock may be integrated into a single unit in which programmable means operate a relay when a pre-selected criterion is met .

[0018] Preferably, the first safety interlock comprises a removable locking means and a switch, whereby removal of the locking means is configured to close said switch . The locking means is a simple structure which can be removed from the mechanical safety interlock for releasing it by the binding means .

[0019] In other words , the first safety interlock is a mechanical safety interlock . Preferably, the second safety interlock is a totally separate system controllable by the operator . The second safety interlock does not receive any message from an autopilot nor communicate with the autopilot . The second safety interlock is unaware of the state of the other safety interlocks .

[0020] Preferably, the automatic control unit is configured to monitor and to release the third safety interlock, irrespective of the state of the first or the second safety interlocks . In other words , the automatic control unit monitors the criteria when the vehicle is already in motion and on its way to the target .

[0021] The mechanical binding means may be a cord, a cable wire , a line , or a string having of length of 1 to 5 m, preferably 2 to 3 m . Thanks to its suf ficient length, the binding means , or preferably a safety wire , can be connected to a solid obj ect even i f the solid obj ect were not in the immediate vicinity of the launching point of the vehicle . On the other hand, the binding means is suf ficiently short to release the first safety interlock fairly close to the launching point , and an explosion resulting from unintended firing of the explosive charge will only spread over a relatively small area in case the vehicle is an aerial vehicle .

[0022] The most preferable embodiment is one , wherein only one of the second and third safety interlocks is electromechanical and the other is semiconducting, whereby the safety interlocks have di f ferent failure mechanisms and are not sensitive to similar types of interference .

[0023] Preferably, both the trigger and the second safety interlocks are relays . A relay is a very simple and reliable device which can be easily operated by remote control . Further, a relay is also suitable for being easily restored to its open position i f the conditions for explosion are not met .

[0024] In an embodiment , the first safety interlock is a mechanical safety interlock, whereas the second and third safety interlocks are electronic safety interlocks .

[0025] In this context , the first safety interlock refers to a safety interlock which is released by a binding means , either by removing a locking means or by otherwise acting on the first safety interlock to release it by transmitting a force ef fective on the binding means .

[0026] Preferably, the communication means comprise a ground control station with indicating means for indicating the state of the safety interlocks of the vehicle to the operator . By the indicating means , the operator can eas ily monitor the state of the safety interlocks before triggering the explosive charge even i f the operator had, for example , no visual contact to the vehicle .

[0027] In an embodiment , the indicating means are lights for indicating the state of the security interlocks of the vehicle visually to the operator . Lights are a very inexpensive and simple way to indicate the state of the safety interlocks to the operator .

[0028] Preferably, the automatic control unit comprises at least one sensor for monitoring a variable selected for the selected criterion . The criterion may be, in its simplest form, e . g . position data of the positioning means acting as a sensor, wherein for the position data, the criterion has been set to release the third safety interlock . Preferably, the automatic control unit comprises several sensors for monitoring the selected variable for the selected criterion, the sensors including two or more of the following : an inertial measurement unit comprising a gyroscope or a 3- axis acceleration sensor, or both; a barometer ; a magnetometer ; positioning means ; or LIDAR . Consequently, the criterion for releasing the third safety interlock may be formed by a more complex decision-making process to eliminate a moment of danger caused by incorrect data from a single sensor .

[0029] Preferably, the automatic control unit includes means for returning at least one safety interlock to the safety position on the basis of the second criterion . This makes it possible to return the vehicle to the launching point without firing the explosive charge i f a criterion for triggering is not met .

[0030] In an embodiment , the first safety interlock, the second safety interlock and the third safety interlock are part of the electric circuit which also includes the power source and the trigger, wherein the second safety interlock and the third safety interlock are arranged on di f ferent sides of the electric circuit in relation to the trigger, one upstream and the other downstream of the trigger . By such a solution, it is possible to make sure that failure of a single line in the circuit does not enable the current to flow to the trigger, because part of the safety interlocks is arranged on a di f ferent line . In this way, the safety interlocks between the power source and the trigger are doubled for improving safety .

[0031] Preferably, the unmanned vehicle i s a drone in which the power unit includes propellers and motors for rotating them . In particular, drones play a signi ficant role in modern warfare , and they are commonly used for carrying explosive charges for destroying targets . The drone used may be , in principle , any commercial drone which is suitable for the purpose and is provided with a three-stage safety interlock system according to the invention .

[0032] Preferably, the vehicle is equipped with so-called First-Person-View ( FPV) equipment including a camera arranged in connection with the vehicle , as wel l as a display arranged in connection with the ground control station, by which the operator can monitor and control the movements of the vehicle when the vehicle is beyond visual line of sight .

[0033] In an embodiment , the ground control station may also include second indicating means for indicating the state of the safety interlocks to the operator . In this way, the operator can detect i f the autopilot has already found that the criteria for releasing the third safety interlock are met , in which case triggering only requires the release of the second safety interlock by the operator .

[0034] The aim of the method according to the invention can be achieved by a method for operating a remote controlled vehicle , which method is implemented by the following steps comprising equipping the vehicle with an explosive charge ; starting the automatic control unit of the vehicle for controlling the vehicle ; and releasing the first safety interlock, wherein for releasing the first safety interlock, the f irst safety interlock of the vehicle is fastened to a solid obj ect by means of a mechanical binding means , and the first safety interlock is released by steering the vehicle to a location beyond the reach of the binding means . Furthermore , the method comprises releasing the second safety interlock manually via remote control by the operator, or by a manual switch, and releasing the third safety interlock by an automatic control unit when a selected criterion is met , and triggering the explosive charge . In the method according to the invention, the safety interlocking is released in three steps , wherein each step is independent of the preceding one , wherein failure of one safety interlock does not endanger the vehicle . The first safety interlock to be released by a mechanical binding means increases safety, since the operator does not need to be present at the vehicle to release the first safety interlock . On the other hand, by means of the mechanical binding means , the first safety interlock is released sufficiently close so that an eventual accidental explosion of the vehicle does not cause equally much damage in case the vehicle is an aerial vehicle .

[0035] Preferably, in the method, the operator moves to a safety distance from the vehicle before it is launched and the first safety interlock is removed when the vehicle is in motion . In this way, the safety of the operator is secured in connection with launching of the vehicle .

[0036] In an embodiment , the automatic control unit releases the third safety interlock and fires the explosive charge i f the pre-set criteria for triggering, monitored by the autopilot , are met . Thus , the implementation of the triggering will only depend on whether the first safety interlock and the second interlock have been released as well .

[0037] In the method, it is possible to apply the indicating means belonging to the ground control station to indicate the state of the safety interlocks of the vehicle to the operator, preferably visually . In this way, it is easy for the operator to detect the state of the safety interlocks before applying the trigger manually . The selected criterion may be detection of the operation of the power unit , power production o f the power unit , and detection of acceleration in the aggregate . In this way, it can be reliably concluded that the vehicle has set of f from the launching point .

[0038] Preferably, the third safety interlock is a programmable unit which applies a selected criterion to release and enable the application of the trigger by the autopilot or the operator .

[0039] Preferably, the automatic control unit examines the ful filment of the criterion selected as a condition for releasing the third safety interlock, and gives a release command to the third safety interlock when the criteria are met .

[0040] In the method according to the invention, the unmanned vehicle according to the invention is preferably an aerial vehicle , most preferably a drone , i . e . a miniature helicopter, but the vehicle may also be a remote controlled unmanned vehicle movable on the ground or in water .

[0041] The invention, which is not limited to the embodiments to be presented hereinbelow, will be described in more detail with reference to the appended figures , in which

[0042] Description of the drawings

[0043] Fig . 1 shows a principle side view of a vehicle according to the invention, the vehicle being a drone ;

[0044] Figs . 2a to 2d show steps of the method according to the invention in principle side views ; Fig . 3a shows a principle block chart of a preferred coupling of safety interlocks in the vehicle ;

[0045] Fig . 3b shows the preferred coupling of Fig . 3a in more detail with respect to the components ;

[0046] Fig . 3c shows a principle block chart of an alternative coupling of the safety interlocks in the vehicle ;

[0047] Fig . 4a shows steps of the method according to the invention in a block chart ;

[0048] Fig . 4b shows steps of the method according to the invention with respect to a more detailed embodiment in a block chart ;

[0049] Fig . 5 shows block charts illustrating monitoring of criteria preventing the launching of the vehicle , according to an embodiment , by the autopilot of the vehicle ;

[0050] Fig . 6 shows an alternative vehicle in a side view .

[0051] Detailed description of the invention

[0052] Figures 1 to 2d show a most preferred embodiment of a vehicle 10 according to the invention, wherein the vehicle is a miniature helicopter, i . e . a drone 60 , which is a remote controlled unmanned aerial vehicle 10 which can be used for carrying an explosive charge 16 . Unlike Figs . 1 to 2d, the vehicle according to the invention can also be implemented as a vehicle moving in water, as shown in Fig . 6 , or as a vehicle moving on the ground, which is not shown in the figures . Referring to Figs . 1 to 2d, in all the embodiments the vehicle 10 comprises a frame 12 equipped with a power unit 14 for propulsion of the vehicle 10 . In the embodiment of Figs . 1 to 2d, the power unit is a propeller unit comprising at least two propellers 68 with respective motors 70 for generating li ft on the vehicle 10 , as well as for steering it . Instead of a drone , the aerial vehicle may also be a flying vehicle comprising wings , unlike a drone . Further, the vehicle 10 always comprises an explosive charge 16 fitted to be carried by the vehicle 10 , a power source 18 , and a trigger 20 connected between the power source 18 and the explosive charge 16 for triggering the explosive charge 16 , as shown in Figs . 3a to 3c . In this context , triggering the explosive charge 16 may refer either to detonating the explosive charge 16 or alternatively the removal of the explosive charge from the vehicle 10 , in which case the explosive charge 16 will detonate first on the target . The explosive charge may be , for example , a charge that explodes on contact , detonating upon hitting the target after being dropped . Alternatively, the explosive may be an explosive charge detonating in the vehicle , simultaneously destroying the vehicle .

[0053] For safety locking of the explos ive charge , the vehicle 10 comprises a three-part safety locking system comprising the first safety interlock 22 and the remote controlled second safety interlock 24 connected to the explosive charge 16 , arranged between the power source 18 and the explosive charge 16 , as shown in Figs . 3A and 3b, and the third safety interlock 40 . The above-presented safety interlocks are autonomous components , separate from each other, to be released in di f ferent ways . The first safety interlock 22 may comprise , for example , a mechanically releasable locking pin or a corresponding locking means which is removed to release the safety interlocking . Preferably, the above mentioned second safety interlock 24 and trigger 20 are relays 44 in an electric circuit 58 , as shown in Figs . 3a to 3c .

[0054] The first safety interlock 22 is released by using a mechanical binding means 30 which is preferably a cord or another similar elongated and flexible piece . The binding means 30 is connected, at its one end 32 , to the first safety interlock 22 and, at its other end 34 , to a solid obj ect 38 at the launching point 36 of the vehicle 10 , as shown in Fig . 2c . After the vehicle 10 has set of f , the binding means 30 releases the first safety interlock 22 by, for example, removing the locking means 23 as the vehicle 10 moves further from the launching point 36 . The solid obj ect 38 may be , for example , the ground to which the binding means 30 can be fastened by using a fastening means 64 which may be , for example , a mechanical device resembling a tent peg . Alternatively, the binding means can be tied, at one end, to a solid obj ect , if possible .

[0055] The second safety interlock 24 , in turn, is a safety interlock to be released via remote control by the operator 52 using communication means 28 . Preferably, the vehicle 10 may include separate indicating means 48 for providing the operator 52 with information about the current state of the safety interlocks , i . e . whether safety interlocks have been released . When the operator is informed by the indicating means of the release of the safety interlocks , the operator can use the communication means to release the second safety interlock .

[0056] Preferably, the indicating means may be lights , one for each safety interlock . By means of the lights , the operator can easily detect the state of the safety interlocking of the explosive charge of the vehicle before giving a trigger command . Further, the vehicle 10 includes an automatic control unit 26 for steering the vehicle 10 and for controlling the third safety interlock 40 according to a selected criterion . The automatic control unit 26 is preferably a so-called autopilot which comprises at least one sensor, preferably several sensors , on the basis of which the vehicle is steered . The control of the vehicle may be fully automated, based on positioning and the set target where the explosive charge is to be carried . Alternatively, the control may be semi-automatic, whereby control commands are received from the operator 52 who operates the vehicle by using communication means 28 of the vehicle 10 , preferably from a ground control station 46 . In such a case , the automatic control unit converts the control commands from the ground control station 46 to control commands of the power unit , whereby the movement of the vehicle 10 is achieved as desired by the operator .

[0057] The release of the third safety interlock 40 is based on control from the automatic control unit 26 , including a criterion for releasing the third safety interlock 40 . The criterion may be based on data from a single sensor, or preferably combined data from several sensors , wherein the criterion for releasing the third safety interlock 40 is fulfilled when all the conditions are met . Examples of criteria may include , for example in the case of the drone 60 in Fig . 1 , running of the motors 70 rotating the propellers 68 of the power unit 14 , power output , and acceleration of the vehicle , all received from di f ferent sensors . Alternatively, a criterion may be , for example , a barometric reading combined with position data . The purpose of the criterion is to secure that the vehicle is at a suf ficient distance from the launching point so that the third safety interlock can be removed without causing a danger to the operator of the vehicle . The automatic control unit used in the vehicle , preferably an autopilot , may be a unit according to the Pixhawk standard or preferably the FMUv5 standard . Preferably, when the vehicle is a drone , the control unit comprises two or more detecting sensors which preferably include three inertia measurement units comprising a gyroscope and a 3-axis acceleration sensor for measuring acceleration and orientation of the vehicle , a barometer for altitude data of the vehicle , a magnetometer, positioning means , such as GPS or the like , and a light detector for ranging, i . e . LiDAR, for examining the environment . Three equivalent sensors are preferably used at the same time so that the vehicle would be functional even i f one of the sensors is faulty . By means of such sensors , vehicle control commands can be generated very reliably for the drone . I f the vehicle is a unit with simpler control , moving on the ground or in water, the automatic control unit can be implemented, for example , without the gyroscopes and the barometer .

[0058] In addition to the sensors , basic components of the control unit include a computing unit for performing computations , a memory for storing programmable means and measurement values , communication means , and preferably also an extended Kalman filter (EKF) . The purpose of the EKF is to eliminate the ef fect of single error measurements on the control , to maintain the control stable . Hereinafter, the automated control system will be called an autopilot .

[0059] Preferably, a trigger command to the trigger is always received via the third safety interlock, and the autopilot operates the trigger i f the criteria for releasing the third safety interlock are ful filled .

[0060] Triggering the explosive charge is preferably a manual operation, but the vehicle may also comprise an automated triggering system . The triggering of the explosive charge is automatic i f the criteria for releasing the third safety interlock, monitored by the autopilot , are met and the first and second safety interlocks have been released .

[0061] The communication means between the vehicle and the ground control station are preferably communication means applying radio waves for implementing the communication between these two . Preferably, the radio communication is encrypted by using known encryption techniques . In some cases , the communication means may be wired .

[0062] Figures 2a to 2d show steps of using a vehicle 10 , all the way from starting the vehicle 10 to a situation preceding triggering, with reference to steps 100 to 136 in the block chart of Fig . 4a . Figure 2a shows the initial situation in which an explosive charge 16 is fastened to the vehicle 10 which is a drone on the ground . In a preliminary step 100 , the first end 32 of a binding means 30 is fastened to a first safety interlock 22 , for example a locking pin, and the second end 34 is fastened in step 102 to a launching point 36 , preferably a solid obj ect 38 , such as the ground . For fastening the second end, a fastening means 64 can be used, which may be , for example , a locking wedge or a tent peg like structure to be pushed into the ground . In a first step 104 of launching the vehicle , an operator 52 connects a payload by applying a switch e . g . by the side of the vehicle 10 , whereby the success ful connection can be indicated to the operator in step 106 by indicating means of the vehicle , for example with a green light . Red light in the indicating means of the vehicle , in turn, may indicate that it is dangerous to approach the vehicle . When green light is lit , in step 108 , the operator moves to a ground control station 46 at a safe distance from the vehicle , as shown in Fig . 2b, and starts to steer the vehicle 10 in step 110 . The steering of the vehicle may take place automatically by an autopilot based on a target destination, i . e . a map location, set by the operator via the ground control station . The safe distance may be , for example 10 to 20 m . It should be noted that Figs . 2a to 2d are only exemplary, and the dimensions of and distances between the di f ferent components do not correspond to reality .

[0063] In step 112 , as shown in Fig . 2c, the vehicle 10 moving away from the launching point 36 , the binding means 30 is straightened and finally, in step 114 shown in Fig . 2d, it releases the first safety interlock 22 preferably by removing the locking means 23 from the vehicle 10 which moves beyond the reach of the binding means 30 .

[0064] Next , after detecting the success ful launch of the vehicle , the operator can manually release the second safety interlock by remote control or by a manual switch in step 116 . The operator can detect the success ful launch visually either by direct visual contact or via a camera, whereby the drone is at a suf ficient distance from the launching location, for releasing the second safety interlock via the ground control station .

[0065] In step 118 , the autopilot continuously monitors the meeting of the criterion for the third safety interlock and may, after a selected time limit from the launch, for example after 60 seconds , determine the take-of f of the drone to be successful according to a selected criterion, for example on the basis of the barometer or the functional state of the power unit , its history and acceleration . This may be one criterion required for releasing the third safety interlock . Otherwise , the monitoring of the take-of f in step 116 is continued until the criterion is met . The time limit may range from 10 to 300 s . In step 120 , the meeting o f the criteria for releasing the third safety interlock is pre ferably monitored by the autopilot continuously during the flight . In step 122 , the autopilot continuously monitors the criteria for releasing the third safety interlock, and i f these are met , the third safety interlock can be released . In step 124 , a trigger command from the autopilot or the operator via the ground control station is transmitted to the trigger which triggers the explosive charge .

[0066] As an alternative to triggering by the operator, the autopilot may be configured to monitor the state of the connection to the ground control station . I f the connection is lost before receiving a trigger command from the operator in a situation in which the first and second safety interlocks have already been released and the criteria monitored by the autopilot for releasing the programmable third safety interlock are met , the autopilot may perform triggering when the criterion selected for triggering is met . The criterion for triggering may be , for example , a vertical distance from the target , determined by LiDAR, and position data . In this context , the LiDAR is preferably, in its simplest form, a distance gauge which does not form a 3D point cloud . Thus , the investment cost for the LiDAR is quite moderate .

[0067] Figure 4b shows a more detailed representation of the steps of the method in a block chart . The operation of the vehicle is started in step 200 , in which the operator has turned on the vehicle and the vehicle is remote controlled via a ground control station . In step 202 , the logic of the indicating means detects whether electricity is conducted by any of the safety interlocks . I f any of the safety interlocks is intentionally released, the indicating means of the vehicle , for example a red LED light , is used in step 204 to indicate that it is not safe to connect a detonator to the vehicle . I f the safety interlocks are secured, the red l ight is not lit in step 206 .

[0068] In step 208 , the connection of the explosive charge is monitored, and i f the connection was made manually, the operator can also be indicated by the indicating means , preferably a green light , that the explosive charge is connected in step 210 . Subsequently, the operation of the vehicle can be started in step 212 , in which the safety interlocks are on and the explosive charge has been connected .

[0069] In step 214 , as the first safety interlock is released, the green light goes of f so that it will not be visible when the vehicle moves towards the target . In steps 216 to 226 , the autopilot monitors the criteria for releasing the third safety interlock, first in step 216 whether the vehicle has been in motion for a selected time threshold, for example 10 seconds . Until then, the red LED light is shown to the operator in step 218 to indicate that the vehicle is dangerous and at least one safety interlock has been released . When the time threshold is passed, the process moves to step 220 in which the autopilot examines i f the flight mode is landing mode in which the explosive charge is triggered when the vehicle descends to a desired height distance from the target . I f this is the case , the process moves to step 226 to examine whether the height distance from the target , given by LiDAR or another distance sensor, is shorter than a selected criterion, for example 20 m . I f these criteria are not met , the trigger remains locked and the process returns to step 214 . I f , on the other hand, the criterion related to the height i s met , the third safety interlock is released .

[0070] I f , on the other hand, the flight mode in step 220 is not the landing mode , the process moves to step 222 in which it is checked whether the flight mode is automatic, i . e . programmed to travel along a pre-programmed route , and triggering takes place at a way point or, alternatively, the flight mode is determined to be the landing mode, wherein the drone lands before triggering. If this is the case, the process moves to step 226 again to check whether the height distance is suitable for meeting the criterion. Again, if the criterion is met, the third safety interlock is released.

[0071] If, on the other hand, the autopilot was not defined in step 220 to steer the vehicle to land, the process moves to step 224 in which the autopilot examines if the operator has given a trigger command, and further to step 226, in which the vertical distance of the vehicle to the target is examined. If the operator has given a trigger command, the autopilot will release the third safety interlock and activate the trigger.

[0072] In step 228, if it is monitored that the safety interlocks have been released for a time longer than the preselected time threshold, for example for more than 15 minutes while the connection to the ground station has been cut off, the safety interlocks are returned to the locking position. If not, the process moves to step 230 to examine whether the operator has released the third safety interlock. If not, no explosion will take place. If, on the other hand, the operator releases the second safety interlock, the circuit closes as a whole and, according to a trigger command given earlier by the autopilot, the explosive charge is triggered in step 232.

[0073] In this context, it should be understood that the operation of the first, second and third safety interlocks is autonomous and may take place in an order different from that presented in the embodiments shown in the figures. Most preferably, the first safety interlock is released first, upon take-off of the vehicle; the second safety interlock is released by the operator when detecting that the take-off was successful; and the third safety interlock is released by the autopilot in a situation where the criteria for releasing the explosive charge are met . After all the safety interlocks have been released, the explosive charge is triggered by a trigger command from the operator or the autopilot .

[0074] Figures 3a to 3c show two embodiments of an electric circuit 58 enabling an embodiment of a vehicle according to the invention, wherein Figs . 3a and 3b illustrate the same implementation, and Fig . 3c shows an alternative implementation . Both have the same basic components for the safety interlocking, i . e . the first safety interlock 22 , the second safety interlock 24 and the third safety interlock 40 . However, the embodiment of Figs . 3a and 3b is a preferred embodiment , because the first safety interlock 22 , the trigger 20 and the third safety interlock 40 are connected on a di f ferent line of the electric circuit 58 , with respect to the explosive charge 16 , than the second safety interlock 24 . The control commands of the trigger 20 are always directed via the programmable third safety interlock 40 which is released by the autopilot 26 .

[0075] I f one line in the circuit from the power source 18 to the explosive charge 16 is damaged, the circuit is not completed because the second safety interlock 24 is located in a di f ferent line of the circuit than the first safety interlock 22 , the third safety interlock 40 and the trigger 20 , which are immune to a failure on one side . In view of safety, it is also important that the second safety interlock 24 and the third safety interlock 40 receive their release signals from di f ferent sources which are independent of each other . The third safety interlock 40 receives its signal from the sensor or sensors 54 of the control unit 26, i . e . the autopilot , whereas the second safety interlock 24 receives its control signal from the operator at the ground control station 56 to the receiver 42 of the vehicle 10. Furthermore, the trigger command to the trigger always comes via the third safety interlock, irrespective of whether it comes from the autopilot or the operator.

[0076] The embodiment of Fig. 3c is, in normal operation, functionally similar to the embodiment of Figs. 3a and 3b but is more susceptible to failure. In this embodiment, for example, a fault in the circuit board may cause, for example, bypassing of the safety interlocks. When the safety interlocks are arranged on two sides, in different lines, as shown in Figs. 3a and 3b, bypassing one side will not yet cause triggering of the explosive charge. Bypassing may occur, for example, if there is moisture on the circuit board, if a component has been broken into a short circuit, or if there is conductive contamination, such as metal dust, on the circuit board.

[0077] In an example according to at least one embodiment, an unmanned vehicle 10 has been provided which comprises

[0078] - a frame 12,

[0079] - a power unit 14 connected to the frame 12, for propulsion of the vehicle 10,

[0080] - means for fitting an explosive charge 16 to be carried by the vehicle 10,

[0081] - means for connecting a power source 18 to the vehicle for forming an electric circuit,

[0082] - means for connecting a trigger 20 to said electric circuit, between the power source 18 and the explosive charge 16, for triggering the explosive charge 16,

[0083] - a first safety interlock 22 and a second safety interlock 24 between the power source 18 and the explosive charge 16 in said electric circuit,

[0084] - a control unit 26 for controlling the vehicle 10, and

[0085] - communication means 28 for steering the vehicle 10. Said second safety interlock 24 is a manual switch, or said second safety interlock 24 is remote controlled and comprises a receiver 42 for receiving a second control signal given by the operator via remote control by us ing communication means 28 . Furthermore , the vehicle 10 comprises

[0086] - a mechanical binding means 30 to be fastened, at its one end 32 , in a removable way to said vehicle 10 and, at its other end 34 , to a solid obj ect 28 in connection with the launching point 36 of the vehicle 10 , said binding means 30 being arranged to release the first safety interlock 22 when the vehicle 10 moves further from the launching point 36 , beyond the reach of the binding means 30 , and

[0087] - a third safety interlock 40 configured to be controlled by said control unit 26 according to a selected criterion, wherein said first safety interlock 22 , second safety interlock 24 and third safety interlock 40 are configured to control the electric circuit 58 in which said second safety interlock 24 and third safety interlock 40 are arranged on di f ferent sides of the electric circuit 18 with respect to said trigger 20 , one upstream and the other downstream of the trigger 20 , and the first safety interlock 22 is arranged on the same side of the electric circuit as the third safety interlock 40 , wherein when the electric circuit is open, one of the first safety interlock 22 and the third safety interlock 40 is in locked position on the other side of the electric circuit , and a trigger command received by a manual switch or received via remote control by using the communication means 28 will result in triggering of the explosive charge when the circuit is closed, when the second safety interlock 24 on the first side of the circuit is released, and both the first safety interlock 22 and the third safety interlock 40 are released on the second side of the circuit .

[0088] In an example , the means for fitting the explosive charge 16 to be carried by the vehicle 10 comprise fastening means in the vehicle, for fastening the explosive charge to the vehicle in a removable way. The fastening means may comprise at least one of the following: the frame structure of the vehicle, such as a recess, for fitting an explosive charge to be carried by the vehicle; a rope; or a cable; or fasteners, such as claws, for gripping the explosive charge.

[0089] In an example, the means for connecting the power source 18 to the vehicle, for forming the electric circuit, comprise at least one of the following: the frame structure of the vehicle, such as a recess, for fitting the power source to be carried by the vehicle; electric conduits for connecting to the terminals of the power source; fasteners, such as claws, for gripping the power source.

[0090] In an example, the means for connecting the trigger 20 between the power source 18 and the explosive charge 16 in said electric circuit, for triggering the explosive charge 16, comprise at least one of the following: the frame structure of the vehicle, such as a recess, for fitting the trigger to be carried by the vehicle; electric conduits for connecting to the terminals of the trigger; electric conduits for connecting the trigger to the control unit 26; fasteners, such as claws, for gripping the trigger.

[0091] In an example, the vehicle 10 may comprise a manual switch for controlling the second safety interlock. The manual switch may be an electromechanical switch by which a touch by the operator may result in closing of the electric circuit and thereby releasing of the safety interlock. Examples of electromechanical switches include a lever switch, a contact button, and a slide switch . In an example , the second safety interlock is remote controlled by means of a control signal . The control signal received from a device operated by the operator may be a radio frequency (RF) signal , an optical signal , and / or an audio signal , and these may be modulated by an analogue and / or digital method or methods for carrying the control signal from a device operated by the operator to the receiver of the vehicle .

[0092] In an example , the vehicle comprises communication means 28 for operating the trigger 20 via remote control .

[0093] In an example , the vehicle comprises communication means 28 for operating the safety interlock 24 via remote control .

[0094] In an example , the mechanical binding means is arranged to be fastened to said vehicle 10 in a removable way . The binding means may be fastened to a locking means 23 for the first safety interlock, the locking means being arranged to close the switch when the locking means is removed . Preferably, the binding means is fastened to a sol id obj ect and to the locking means , and the locking means comes of f when the vehicle pro- ceeds / moves further from the solid obj ect , generating a force ef fective on the locking means via the binding means and resulting in removal of the locking means .

[0095] In an example , safety interlocking, such as the first safety interlock 22 , the second safety interlock 24 and the third safety interlock 40 , is arranged to control the completion of the electric circuit . When the safety interlock is on, the safety interlock keeps the electric circuit open . When the safety interlock is released, the safety interlock closes the electric circuit . Consequently, said electric circuit is open when, on the first side of the electric circuit , the second safety interlock 24 is on, or, on the second side of the circuit, either one of the first safety interlock 22 or the third safety interlock 40 is on. On the other hand, the circuit is closed when all the safety interlocks are released. Thus, the triggering of the explosive charge takes place first after a trigger command has been received via remote control from the operator using communication means 28, or by means of a manual switch. It should be noted that the safety interlocks thus operate as part of the electric circuit, and on the other hand, they may constitute part of the circuit.

[0096] Figure 5 shows, in block charts, an implementation according to an embodiment in which the autopilot examines the following criteria preventing the take-off of the vehicle, and their fulfilment before the release of the third safety interlock. Any one of these criteria, when met, prevent the take-off. In step 252, the voltage of the power source 18 is monitored, and if it is, for example, below 22 V, this will result in a situation where the monitoring causes preventing 278 the release of the third safety interlock. Correspondingly, other criteria to be examined may include examining the autopilot or the vehicle in step 254. In addition, the difference between the primary and secondary angular speeds of the gyroscope 266 may be examined, wherein a difference greater than 5° / s, for example, causes preventing 278 of the release. A difference in the acceleration of the primary and secondary sensors of the acceleration sensor 270 greater than 0,75 m / s2, a height difference measured by the barometer 258 or inertia measuring unit 260 greater than 2 m in step 262, poor quality of heading data measured by the inertial measuring unit 260 in step 272, or too strong a magnetic field of the compass 274 in step 276 will all result in preventing 278 of the release of the third safety interlock as well. Figure 6 shows a second embodiment of the vehicle according to the invention, wherein the vehicle 10 is a water vehicle 66 . When the water vehicle 66 moves to a suf ficient distance from the launching point 36 , the binding means 30 fastened to the first safety interlock 22 will release the first safety interlock 22 .

[0097] As a feature not belonging to the invention, it is feasible that the unmanned vehicle presented in the claims may be used for a purpose other than carrying an explosive charge , wherein a given payload is delivered to a destination and the payload is released . Such applications may include , for example , transporting and releasing a chemical mass used for firefighting onto a fire i f the unmanned vehicle is a drone or a flying vehicle . Even in such an implementation, the three-stage interlocking according to the invention is necessary .

[0098] In some cases , features presented in this application can be used as such, irrespective of other features . On the other hand, features presented in this application can be combined, where necessary, to make di fferent combinations . Even i f some steps or the device have been presented as a whole , they may be divided in parts , in which case some steps or parts of the device may be omitted or their order may be changed .

[0099] It will be obvious for a person skilled in the art that technological advances will entail a variety of implementations of the basic idea of the invention . Thus , the inventions and the embodiments are not limited by the examples described above , but they can be varied within the scope of the claims .

Claims

CLAIMS1. An unmanned vehicle (10) comprising- a frame ( 12 ) ;- a power unit (14) connected to the frame (12) , for propulsion of the vehicle (10) ;- means for fitting an explosive charge (16) to be carried by the vehicle (10) ;- means for connecting a power source (18) to the vehicle, for forming an electric circuit;- means for connecting a trigger (20) between the power source (18) and the explosive charge (16) in said electric circuit, for triggering the explosive charge (16) ;- a first safety interlock (22) and a second safety interlock (24) between the power source (18) and the explosive charge (16) in said electric circuit;- a control unit (26) for controlling the vehicle (10) ; and- communication means (28) for controlling the vehicle (10) ; wherein said second safety interlock (24) is a manual switch, or said second safety interlock (24) is remote controlled and comprises a receiver (42) for receiving a second control signal given via remote control by the operator using communication means (28) ; the vehicle (10) further comprising- a mechanical binding means (30) to be fastened at its one end (32) to said vehicle (10) in a removable way and at its other end (34) to a solid object (38) at the launching point (36) of the vehicle (10) , wherein said binding means (30) is arranged to release the first safety interlock (22) when the vehicle (10) proceeds further from the launching point (36) , beyond the reach of the binding means (30) ; and- a third safety interlock (40) configured to be controlled by said control unit (26) on the basis of a selected criterion; wherein said first safety interlock (22) , second safety interlock (24) and third safety interlock (40) are arranged to control the electric circuit (58) , in which said second safety interlock (24) and third safety interlock (40) are arranged on different sides of the circuit (18) with respect to said trigger (20) , one upstream and the other downstream of the trigger (20) , and the first safety interlock (22) is arranged on the same side of the circuit as the third safety interlock (40) ; wherein when the circuit is open, on the second side of the circuit either one of the first safety interlock (22) and the third safety interlock (40) is on, and a trigger command, received via remote control by the communication means (28) or received from the manual switch, causes triggering of the explosive charge when the circuit is closed, when the second safety interlock (24) on the first side of the circuit is released and both the first safety interlock (22) and the third safety interlock (40) on the second side of the circuit are released.

2. The vehicle according to claim 1, wherein the third safety interlock (40) is a programmable unit arranged to be released by a selected criterion and to enable the activation of the trigger (20) .

3. The vehicle according to claim 2, wherein said automatic control unit (26) is arranged to examine the meeting of the selected criterion for releasing the third safety interlock (40) and to give a release command to the third safety interlock (40) when the criteria are met.

4. The vehicle according to any of the claims 1 to 3, wherein the mechanical binding means (30) is a string, a cable, a cord, or a line, whose length is 1 to 5 m, preferably 2 to 3 m.

5. The vehicle according to any of the claims 1 to 4, wherein both the second safety interlock (24) and the trigger(20) are relays (44) .

6. The vehicle according to any of the claims 1 to 5, wherein the vehicle (10) comprises indicating means (48) for indicating the state of at least one of the safety interlocks (22, 24, 40) to the operator (52) .

7. The vehicle according to claim 6, wherein the indicating means (48) comprise a light for indicating the state of at least one of the safety interlocks (22, 24, 40) visually to the operator (52) .

8. The vehicle according to any of the claims 1 to 7, wherein the automatic control unit (26) comprises at least one sensor (54) for examining a selected variable for a selected criterion .

9. The vehicle according to any of the claims 1 to 8, wherein the automatic control unit (26) comprises a number of sensors (54) for monitoring a selected variable for a selected criterion, the sensors (54) including two or more of the following: an inertia measuring unit comprising a gyroscope or a 3-axis acceleration sensor, or both, a barometer, a magnetometer, positioning means, or LiDAR.

10. The vehicle according to any of the claims 1 to 9, wherein said first safety interlock (22) , second safetyinterlock (24) and third safety interlock (40) are part of an electric circuit (58) which also comprises said power source (18) and trigger (20) , wherein said second safety interlock (24) and third safety interlock (40) are arranged on different sides of the circuit (18) with respect to said trigger (20) , one upstream and the other downstream of the trigger (20) .

11. The vehicle according to any of the claims 1 to 10, wherein the first safety interlock (22) comprises a removable locking means (23) and a switch, wherein the removal of the locking means (23) is arranged to close said switch.

12. A method for operating a remote controlled vehicle(10) , the method being implemented in following steps:- equipping the vehicle (10) with an explosive charge (16) ;- starting a control unit (26) of the vehicle (10) for controlling the vehicle (10) ;- releasing a first safety interlock (22) ;- releasing a second safety interlock (24) ;- triggering the explosive charge (16) ; wherein for releasing the first safety interlock (22) , the first safety interlock (22) of the vehicle (10) is fastened by a mechanical binding means (30) to a solid object (38) , and the first safety interlock (22) is released by steering the vehicle (10) beyond the reach of the binding means (30) ; and the method further comprises:- releasing the second safety interlock (24) manually via remote control or by means of a manual switch; and- releasing the third safety interlock (40) by means of the control unit (26) when a selected criterion is met.

13. The method according to claim 12, wherein the operator(52) moves to a safe distance from the vehicle (10) before thevehicle (10) takes off and the first safety interlock (22) is released when the vehicle (10) is in motion.

14. The method according to claim 12 or 13, wherein the control unit (26) triggers the explosive charge (16) if preset criteria for triggering, monitored by the control unit (26) , are fulfilled.

15. The method according to any of the claims 12 to 14, wherein the selected criterion is detection of the running of the power unit (14) , power production by the power unit (14) , and detection of acceleration all together.

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