Feedback following mechanism for unmanned ground vehicles

Abstract

The present invention relates to a following mechanism for unmanned ground vehicles to follow a target and provide feedback to the target, and a method of operating the following mechanism. The invention provides a tracking mechanism for inferring the presence of an obstacle based on measurements of the movement of a spool to which a rope extending between a leader and a follower vehicle is wound, and operating against the resulting loads, and a following method for operating the same. When the presence of an obstacle is inferred, a feedback is also generated.

Description

[0001] FEEDBACK FOLLOWING MECHANISM FOR UNMANNED GROUND VEHICLES

[0002] Technical Field

[0003] The present invention relates to a following mechanism for unmanned ground vehicles to follow a target and provide feedback to the target, and a method of operating the following mechanism.

[0004] Prior Art

[0005] Nowadays, some mobile vehicles, mobile robots and unmanned military vehicle prototypes have introduced the concept of leader following. In order to fulfill this task, mono camera, stereo camera, electro-optical sensors such as LIDAR, ultrasonic sensors, active radio frequency emitting sensors such as RADAR are used. When one or more of these sensors are present on the vehicle, sensor fusion processes are performed for more precise results. With the outputs of these sensors, a virtual world model is created and the route that the robot can follow in this virtual world is planned. Alternatively, the human or vehicle to be followed is equipped with beacons that broadcast radio frequency or visually identify themselves, so that the vehicle or robot to be followed can follow the beacon in terms of distance and direction.

[0006] In order for unmanned ground vehicles (UGVs) to successfully complete different missions such as logistics transportation, search and rescue, autonomous patrolling and reconnaissance surveillance, order and efficiency are required during deployment. The ability of UGVs to follow people or form convoys by follower vehicles plays a major role in ensuring this order and efficiency.

[0007] Communication between the UGV and the followed element is usually via a control station display, visual indicators or voice. Since these communication methods reduce situational awareness and facilitate detection, they can lead to different threats in the operational environment and jeopardize the survival of the UGV and other elements.

[0008] Currently, vehicle or human following systems use electro-optical sensors such as monocamera, stereo camera and LIDAR integrated on the unmanned ground vehicle. Since these sensors have lenses in front of them, they either become unusable or their performance decreases when exposed to dust, dirt and liquid.

[0009] Electro-optical components such as cameras and color sensors are directly affected by ambient light. Although the light frequency used is tried to be filtered by hardware or software, the efficiency of the sensor cannot be obtained in different ambient lights.

[0010] Since human and vehicle detection with electro-optical systems is performed with machine learning algorithms in software, it is directly dependent on other determinant visual elements (trees, roads, buildings, etc.) in the task scene, and therefore has different performance in every environment. However, following and convoy applications should work properly in every desired environment independently of these variables. Convoy and following missions are critical processes where the safety of the elements is at the forefront. Since LIDAR sensors find the distance of the target to be followed through active radiation, they can be easily detected by infrared cameras, which exposes the movement of the convoy during the operation, putting both the military operation and the military elements at vital risk.

[0011] At the current level of technology, in different applications, components such as radio frequency broadcasting antennas, RADAR, ultrasonic sensors are integrated on the unmanned ground vehicle. Since these systems actively broadcast to the external environment, they facilitate the detection of different electronic warfare elements and the unmanned ground vehicle and convoy by opposing elements during the mission.

[0012] In another application demonstrated, a radio frequency receiver is placed on the unmanned land vehicle and an RF transmitter is placed on the human or unmanned land vehicle to be followed. These radio frequency receivers and transmitters (beacons) reduce the speed and efficiency of the convoy as they add weight to the elements that need to be mobile, and at the same time, since they broadcast actively, they facilitate the detection of people, unmanned ground vehicles and convoys by opposing elements.

[0013] When the vehicles, UGVs and people to be followed change, the following algorithm needs to follow each element with the same performance. For this reason, preliminary preparations should be made for each type of element to be followed and software should be integrated into the unmanned ground vehicle. Algorithms such as machine learning and image processing carried out with electro-optical and RF devices bring high computational power and cost.In addition, in following with image processing, in cases where the element to be followed, such as slope starts and ends, comer turns while moving on sloping terrain, even if the element to be followed is momentarily out of the image, vision algorithms and assumptions come into play, which probabilistically puts the function performed at risk.

[0014] Following mechanisms are known in the art that allow the target to be followed by determining the distance to the target by means of a pulley on which a rope attached to a target vehicle is wound and the relative position of the target by means of an arm associated with this target. Communication between vehicles is also provided by visual or audible indicators or unilateral communication systems. Since these communication methods reduce situational awareness and facilitate detection, they can lead to different threats in the operational environment and endanger UGV and other elements. In addition, if the follower vehicle encounters an obstacle, these following mechanisms can create forces that can damage the target and the follower vehicle. Similarly, they are not mechanically resistant to the loads and forces caused by sudden or rapid movements of the followed element.

[0015] In the document numbered WO2023129066A2, a mechanism for following a target vehicle is described, which is positioned on the follower vehicle. The mechanism comprises a rope attached at one end to the target vehicle, a pulley on which the rope is wound, a rod through which the rope passes, and sensors for determining the position of the pulley and rod to determine the position relative to the target vehicle.

[0016] In the document numbered US11148802B1, a method for determining and controlling the position of an unmanned aerial vehicle tethered to a point on an unmanned vehicle is described. A pulley system is used for this purpose. With the pulley system, the total length of the rope can be measured and this information is used to determine the position. There is also a motor connected to the pulley, but it is explained that the motor is used to determine the position of the pulley (rope length). It was also noted that accurate measurement of the rope length depends on keeping the rope taut.

[0017] In the document numbered CN116045968 A, an unmanned aerial vehicle is described which is connected by a cable to a control unit on the ground. The cable is wound on a pulley system on the ground. There is also a motor on the reel. Depending on the position of the drone, the motor controls the reel and keeps the cable taut. It is stated that the force applied to the cable is also taken into account during the control of the reel by the motor. Objects and Brief Description of the Invention

[0018] It is an object of the present invention to provide a following mechanism for unmanned ground vehicles following a leader, which provides mechanical protection in the event that the follower vehicle encounters an obstacle, and a following method for operating the mechanism.

[0019] It is a further object of the present invention to provide a following mechanism and a following method for operating the same, which enables a feedback to be provided to the leader in the event that the follower vehicle encounters an obstacle.

[0020] The invention provides a following mechanism and a following method for operating the following mechanism and a following method for operating the following mechanism, which enables the presence of an obstacle to be inferred from measurements of the movement of a pulley on which a rope extending between the leader and the follower vehicle is wound, and which operates against the resulting loads. When the presence of an obstacle is inferred, a feedback is also generated.

[0021] With the invention, feedback can be given to the followed element about the elevations that the UGV has difficulty in crossing, obstacles it gets stuck in or terrain in which it gets stuck. In this way, it prevents damage to the UGV and the followed element in mobility problems encountered due to terrain conditions. The invention enables unmanned ground vehicles to easily follow people, vehicles or unmanned vehicles in indoor and outdoor environments, in different terrain structures, regardless of weather conditions and ambient light levels, and provides awareness to the followed element.

[0022] Detailed Description of the Invention

[0023] The following mechanism for achieving the objects of the present invention is illustrated in the accompanying figures.

[0024] Figure 1 A perspective view of a following mechanism according to the invention.

[0025] Figure 2 A top view of the following mechanism shown in Figure 1.

[0026] Figure 3 A cross-sectional view of the following mechanism shown in Figure 2 with respect to the B-B plane. Figure 4 A cross-sectional view of the following mechanism shown in Figure 2 with respect to the C-C plane.

[0027] The parts in the figures are numbered individually and the corresponding descriptions are given below.

[0028] 1. Housing

[0029] 2. First cap

[0030] 3. Motor

[0031] 4. Drive shaft

[0032] 5. Brake

[0033] 6. Spool

[0034] 7. First bearing

[0035] 8. Rope

[0036] 9. Second cap

[0037] 10. Direction shaft

[0038] 11. Torsion spring

[0039] 12. Potentiometer

[0040] 13. Direction bar

[0041] 14. Ring

[0042] 15. Second bearing

[0043] The following mechanism according to the invention for following a leader, e.g. a followed vehicle or a person, by a follower vehicle, by determining the orientation and distance of the leader with respect to the follower vehicle, essentially comprises a rope (8) that connects the follower vehicle to the leader, a pulley (6) positioned on the follower vehicle on which the rope (8) is wound so that its free length can be adjusted, at least one orientation sensor to determine the angle of orientation with respect to the leader, at least one first angle sensor connected to the spool (6) and enabling the angular position of the spool (6) to be determined for determining the distance to the leader; and at least one electromechanical mechanism connected to the pulley (6) and capable of working against the rotating pulley (6) to protect the components from sudden loads in the event that the follower vehicle encounters an obstacle.

[0044] Said at least one electromechanical mechanism is at least one motor (3) or at least one motor (3) and at least one brake (5). In a preferred embodiment of the invention, the first angle sensor and the motor (3) are integrated in the form of a servo motor.

[0045] In the event that an obstacle is inferred by using the angular position data of the spool (6) received by at least one first angle sensor, a force in the opposite direction is generated by at least one electromechanical mechanism to prevent sudden movements of the spool (6) and consequently damage to the components of the following mechanism.

[0046] The following mechanism of the invention may comprise a spring associated with the spool (6) to keep the rope (8) taut for reliable determination of the distance, and the rope (8) is preferably kept taut by means of at least one motor (3) acting on the spool (6). In order to measure the tension of the rope (8), the following mechanism also comprises at least one torque sensor. Preferably, the torque sensor is integrated with the motor (3).

[0047] In a preferred embodiment of the invention, there is provided a motor (3) for keeping the rope (8) taut and a brake (5) acting as a brake to protect the components from sudden loads. The motor (3) acts on the spool (6) by means of a drive shaft (4). The brake (5) may also act on the spool (6) via the drive shaft (4), or the brake (5) may act linearly on the spool (6) via a friction surface on the side face of the spool (6). The brake (5) may be a servo brake.

[0048] The following mechanism also includes a housing (1) that provides a connection to the follower vehicle. The housing (1) also provides protection of the components from environmental conditions.

[0049] A hook, ring (14) or similar component is also provided on the rope (8) for attaching the rope (8) to the leader.

[0050] The orientation sensor comprises a direction bar (13), which can move angularly around the point where the rope (8) is separated from the body (1) and is in contact with the rope (8) in such a way that its angular position changes depending on the orientation towards the leader, and a second angle sensor for determining the angular position of the direction bar (13). The direction bar (13) may be in contact with the rope (8) through one or more portions through which the rope (8) is passed. The second angle sensor may be a potentiometer (12). The potentiometer (12) measures the azimuth angle corresponding to the orientation. The direction bar (13) may be connected to the potentiometer (12) by means of a direction shaft (10). A torsion spring (11) can be provided to keep the direction bar (13) and the direction shaft (10) centered when there is no force on the rope (8).

[0051] A first bearing (7) and a second bearing (15) can be used for the bearing of the spool (6) and the direction shaft (10), respectively.

[0052] A first cap (2) and a second cap (9) may also be provided on the housing (1) to provide access to the inside of the housing (1) for purposes such as installation, maintenance and repair of the following mechanism.

[0053] The following mechanism preferably comprises a connection device for the leader and / or an external control unit, which generates a signal indicating that the follower vehicle has encountered an obstacle. Although the connection device is preferably compatible with wireless communication techniques, it is also possible within the scope of the invention to utilize wired communication techniques by means of a cable on the rope (8).

[0054] Using the following mechanism according to the invention, a following method is also carried out comprising the process steps measuring the angular position of the spool (6) by the first angle sensor, calculating the angular acceleration of the spool (6), activating at least one electromechanical mechanism to reduce the angular acceleration of the spool (6) below a predetermined threshold value in the event that the angular acceleration exceeds the threshold value.

[0055] In a preferred embodiment of the invention, in addition to operating at least one brake (5) in such a way as to reduce the angular acceleration of the spool (6) below the threshold value, the process step generating a signal that the follower vehicle has encountered an obstacle if the angular acceleration exceeds a predefined threshold value is also carried out. In a preferred embodiment of the invention, within the scope of the method, the rope (8) is kept taut by means of a motor (3) and a brake (5) is operated to reduce the angular acceleration of the spool (6) below a threshold value. The tension of the rope (8) can be determined by using the torque cycle obtained from a torque sensor data.

[0056] Thanks to the invention, human and vehicle elements can be easily followed in missions performed by unmanned ground vehicles. The invention facilitates the deployment order in missions such as autonomous patrol, logistics dispatch, search and rescue, reconnaissance and surveillance, and ensures that the order of both the leader and the remaining convoy is maintained. The invention, which is intended to be used in military robotic technologies, can also be easily integrated into civilian applications.

[0057] The invention can be used for civilian health sector tasks such as all kinds of search and rescue and evacuation of the wounded. It paves the way for the realization of mobile systems that can be guided by a single person and following the user instead of stretcher systems carried by many people.

[0058] In the field of agriculture and forestry, it is suitable for following a person or a different vehicle for loading the harvest and transporting forestry tools and materials.

[0059] It is also suitable for use in industrial automation and in-plant transportation (milkrun systems, autonomous mobile robots, etc.).

Claims

CLAIMS1. A following mechanism for following a leader, e.g. a followed vehicle or a person, by a follower vehicle, by determining the orientation and distance of the leader with respect to the follower vehicle, comprising a rope (8) that connects the follower vehicle to the leader, a spool (6) positioned on the follower vehicle on which the rope (8) is wound so that its free length can be adjusted, at least one orientation sensor to determine the angle of orientation with respect to the leader and characterized by further comprising at least one first angle sensor connected to the spool (6) and enabling the angular position of the spool (6) to be determined for determining the distance to the leader; and at least one electromechanical mechanism which is at least one motor (3) or at least one motor (3) and at least one brake (5), connected to the spool (6) and capable of working against the rotating spool (6) to protect the components from sudden loads in the event that the follower vehicle encounters an obstacle.

2. A following mechanism according to claim 1, characterized by a first angle sensor and the motor (3) being integrated in the form of a servomotor.

3. A following mechanism according to claim 1, characterized by comprising at least one torque sensor.

4. A following mechanism according to claim 3, characterized by the torque sensor and the motor (3) being integrated.

5. A following mechanism according to claim 1, characterized by comprising a motor (3) for keeping the rope (8) taut and a brake (5) acting as a brake to protect the components from sudden loads.

6. A following mechanism according to claim 1, characterized by comprising a connection device that generates a signal indicating that an obstacle has been encountered.

7. A following method for following a leader, e.g. a followed vehicle or a person, by a follower vehicle, by determining the orientation and distance of the leader with respect to the follower vehicle, characterized comprising the process steps measuring the angular position of a spool (6) by a first angle sensor for determining the angular position of the spool (6) corresponding to the length of a rope (8) for connecting the follower vehicle to the leader, calculating the angular acceleration of the spool (6), if the angular acceleration exceeds a predefined threshold value, activating at least one electromechanical mechanism to reduce the angular acceleration of the spool (6) below the threshold value.

8. A following method according to claim 7, characterized by stopping the spool (6) instead of reducing the angular acceleration of the spool (6) below a threshold value.

9. A following method according to claim 7, characterized by comprising the process step of generating a signal that the follower vehicle has encountered an obstacle if the angular acceleration exceeds a predetermined threshold value.

10. A following method according to claim 7, characterized by keeping the rope (8) taut by means of a motor (3) and operating a brake (5) in such a way as to reduce the rate of change of angular position of the spool (6) below a threshold value.

11. A following method according to claim 10, characterized by determining the tension of the rope (8) using the torque cycle obtained from a torque sensor data.