232 results about "Underwater robotics" patented technology

The invention discloses a reinforcement learning-based AUV behavior planning and motion control method, which belongs to the technical field of underwater robots and aims at solving the problems of limited training experience and difficult application in a real environment as complex task planning by the AUV depends much on manual experience and a control method designed based on an intelligent algorithm needs an accurate environment mode. AUV tunnel detection is defined as a general task; behaviors corresponding to task completion comprise target trending, wall tracking and obstacle avoidance; a control instruction generated by the robot under water to complete the planned behavior is defined as an action; and when the AUV executes a tunnel detection task, a deep reinforcement learning DQN algorithm is used for real-time behavior planning, a corresponding deep learning behavior network is constructed, and planning of the tunnel detection task is completed. The AUV action network is trained by the DDPG method, the AUV is regarded as an environment model, and force-to-state mapping is obtained, thereby realizing the action control of the AUV.

The invention belongs to the technical field of underwater robots, in particular to a long-term fixed-point vertical-section observation-type underwater robot. The long-term fixed-point vertical-section observation-type underwater robot comprises a propulsion section, a stern buoyancy adjusting section, a battery cabin section, an electronic cabin section, a bow buoyancy adjusting section and an observation load section, wherein the propulsion section and the observation load section use open frame structures; the observation load section carries an oceanographic hydrological data observation sensing equipment; the upper part of the propulsion section is provided with a satellite antenna; the stern buoyancy adjusting section, the battery cabin section, the electronic cabin section and the bow buoyancy adjusting section are arranged in a full-sealed pressure resistant cabin; and through double-way buoyancy adjusting of the stern buoyancy adjusting section and the bow buoyancy adjusting section, the motion posture of the underwater robot is adjusted and the underwater robot can hover at a fixed point. The underwater robot realizes a high-accuracy repeatable double-way buoyancy adjusting function and can realize autonomous balancing and fixed-point hovering.

A water environment robotic system that includes a control station, an underwater robotic vehicle, and a water-surface robotic vehicle. The underwater robotic vehicle is in communication with the water-surface robotic vehicle and the water-surface robotic vehicle is in communication with the control station. Accordingly, the water-surface robotic vehicle can act as a relay between the control station and the underwater robotic vehicle. The water-surface robotic vehicle is further capable of detecting the position of the underwater vehicle and automatically adjusting the position of the underwater vehicle in order to maintain general vertical alignment between the two vehicles.

A modular system for building underwater robotic vehicles (URVs), including a pressure vessel system, modular chassis elements, a propulsion system and compatible buoyancy modules. The pressure vessel system uses standardized, interchangeable modules to allow for ease of modification of the URV and accommodation of different internal and external components such as sensors and computer systems. The system also includes standard, reconfigurable connections of the pressure vessel to the modular chassis system. A standardized, modular propulsion system includes a magnetic clutch, and a magnetic sleeve used to power the URV on or off.

The invention in particular relates to a long-term fixed-point observation type underwater robot with a three-body configuration, which belongs to the technical field of underwater robots. The long-term fixed-point observation type underwater robot with the three-body configuration comprises a main body and two sub bodies, wherein the two sub bodies are respectively arranged on the two sides of the main body; the main body comprises a propulsion section, a stern buoyancy adjusting section, a main body battery cabin section, an electronic cabin section, a bow buoyancy adjusting section and an observation load section, which are connected with each other in sequence, wherein the observation load section carries sensing equipment; the stern buoyancy adjusting section, the main body battery cabin section, the electronic cabin section and the bow buoyancy adjusting section are arranged in a full-sealed main body pressure resistant cabin; the top of the external side of the full-sealed main body pressure resistant cabin is provided with a satellite antenna; and the sub bodies comprise sub body battery sets and sub body propellers, wherein the sub body battery sets are arranged in the full-sealed main body pressure resistant cabin, and the sub body propellers are arranged on the stern of the full-sealed main body pressure resistant cabin. The invention has the advantages of long-distance passage voyage, fixed-point operation, autonomous rising and sinking and long-term observation.

The invention relates to the technical field of robots, and provides a master-slave underwater robotic arm delay control method which can achieve coordinated control on the master arm and the salve arm of a master-slave underwater robotic arm in a bad operating environment and under the condition of transmission communication delay. The method comprises the following steps: giving the structure parameters of an underwater robotic arm, and making a delay analysis of the master and slave robotic arms according to a kinematics model of the underwater robotic arm; collecting hydrodynamic factors, and verifying whether the performance of the robotic arm meets the demand of the model according to the kinematics model of the underwater robotic arm; and delaying an action signal of the master arm, caching joint control signals at first n moments in an underwater controller, and calculating the ideal motion position of the joint of the slave arm at a moment n+1 based on a multi-power curve fitting method. The problem that an underwater robotic arm works intermittently due to a bad operating environment and transmission communication delay is solved.

A method for performing operations using a water environment robotic system on a target section of pipeline located in an underwater environment is provided. The method includes the steps of deploying the underwater robotic vehicle into the water and visually inspecting the underwater environment to locate the pipeline and its plurality of weld joints. A cleaning operation is performed at one of the plurality of weld joints using the underwater robotic vehicle. The robotic vehicle can land on the sea floor and deploy a robotic arm to inspect the cleaned weld joint. The underwater can then swim to a next weld joint and land and perform cleaning and inspection operations, which can be repeated until all inspection sites are inspected.

The invention relates to the field of underwater robotics, particularly to a method of tracking an underwater robot by use of an on-water robot to achieve autonomous tracking of the underwater robot by the on-water robot. The underwater robot starts an underwater acoustic communication set MA installed on the back of the underwater robot, and sends navigational state information of the underwater robot periodically to an underwater acoustic communication set MB installed at the bottom of the on-water robot; the underwater acoustic communication set MB sends the navigational state information to an on-water robot computer; the on-water robot computer calculates and outputs a heading angle control command and a speed control command so that the on-water robot moves in accordance with the control commands. The device provided by the invention requires only one on-water robot and two underwater acoustic communication sets with no other auxiliary devices; the underwater acoustic communication sets are easy to install and can be installed anywhere on the back of the underwater robot or at the bottom of the on-water robot; and the autonomous tracking algorithm program is convenient to transform and suitable for various robots.

A modular system for building underwater robotic vehicles (URVs), including a pressure vessel system, modular chassis elements, a propulsion system and compatible buoyancy modules. The pressure vessel system uses standardized, interchangeable modules to allow for ease of modification of the URV and accommodation of different internal and external components such as sensors and computer systems. The system also includes standard, reconfigurable connections of the pressure vessel to the modular chassis system. A standardized, modular propulsion system includes a magnetic clutch, and a magnetic sleeve used to power the URV on or off.

The invention relates to the field of underwater robotics. Based on distance collected every two moments between an underwater robot and an acoustic beacon and sailing distance of the underwater robot during the period, a computer in the underwater robot calculates a steering angle of the underwater robot and controls the underwater robot to sail toward the acoustic beacon. When the distance between the underwater robot and the acoustic beacon decreases to a set value, the underwater robot performs circular motion round the acoustic beacon. Based on a course and speed of the underwater robot and the distance collected between the underwater robot and the acoustic beacon, an improved extended Kalman filter algorithm is used for estimating position of the underwater robot online. According to the invention, the device requires only one acoustic beacon and a range finder, without the need of other auxiliary devices; can be easily transferred to various underwater robots with the range finder easy to install and the correction algorithm program of good transferability; and has the advantages of good stability and reliability, accurate correction, simple installation, long service life and wide application.

The invention relates to underwater robot technique, especially providing a hydraulic-shears, which is formed by a fixing anvil pin, a shearer, a movable shearing cutter, a drawing straight pin, a cylinder, and a piston rod. Wherein, said shearer is in U-shape whose one side is rectangle; the shearer has a horizontal groove guide rail and a cylinder hole at vertical direction; the fixing anvil pin through said cylinder hole is connected to the U-shape bottom edge; another side of U-shape is in post-structure connected with said cylinder; the inner part of post-structure is in chamber structure while a square hole is near the cylinder; the cutter has a groove guide rail through said horizontal direction mounted inside the chamber, to be through said square hole and connected with one end of piston rod via drawing straight pin; and the open of said U-shape structure of said shearer contains steel wire. The invention has simple structure, lower machining precision, non-cutting left of steel wire, smaller size, lighter weight, application of easily changing vulnerable parts, reliable operation and the application of operation unmanned remote-control diving apparatus.

A water environment robotic system that includes a control station, an underwater robotic vehicle, and a water-surface robotic vehicle. The underwater robotic vehicle is in communication with the water-surface robotic vehicle and the water-surface robotic vehicle is in communication with the control station. Accordingly, the water-surface robotic vehicle can act as a relay between the control station and the underwater robotic vehicle. The water- surface robotic vehicle is further capable of detecting the position of the underwater vehicle and automatically adjusting the position of the underwater vehicle in order to maintain general vertical alignment between the two vehicles.

The invention belongs to the technical field of underwater robots, and discloses an underwater robot target tracking method based on deep learning and monocular vision, which comprises the following steps of inputting the images from a video sequence, estimating an underwater transmission map by using a deep learning neural network for each input image, and determining a target orientation; and establishing a direction and a control scheme of the target motion estimation through a transmission graph obtained through a network. According to the novel underwater robot monocular vision target tracking method based on deep learning, the transmission of an underwater image is calculated by a monocular image acquisition method in an underwater environment. For each incoming video frame and an environment without the priori knowledge, a previously trained convolutional neural network is creatively introduced to compute a transmission map, which provides the depth-dependent estimation. According to the method provided by the invention, the target area can be found, and a tracking direction is established.

A metrology device, computer program product and computer-implemented method generating survey data without having the device touch subsea objects being surveyed. The metrology device may be used with an underwater vehicle or diving personnel, and may comprise an inertial navigation system having gyroscopes to detect angular velocity and accelerometers for the detection of linear velocity and transported by an underwater robotic apparatus or diver, the inertial navigation system outputting position and orientation data of the device for storage; an aiding device for collecting image data of the subsea objects, the aiding device being positioned so that the distance and orientation between the optical scanner and the inertial navigation system is known; and a computer for using the position information and image data between a successively visited known point to determine the drift of the metrology device and to use the drift of the metrology device to correct measurements of same.

The invention discloses an unmanned surface vehicle and robotic fish shoal master-slave collaboration system comprising an upper computer, a host and slaves. The upper computer communicates with the slaves through the host by a wireless communication network. The upper computer is arranged in a control center. The host is arranged on an unmanned surface vehicle. The slaves are arranged on each robotic fish of the robotic fish shoal. The unmanned surface vehicle acts as a signal transmission intermediate station to transmit the detection signals of the underwater detectors, i.e. the robotic fishes, to the upper computer through the unmanned surface vehicle so that the power of signal transmission can be enhanced, the distance of signal transmission can be increased, the robotic fish shoal is quite close to the unmanned surface vehicle, real-time communication between the underwater robotic fishes and the unmanned surface vehicle can be realized, and thus the signal stability and the operation and movement radius of the whole robotic fish shoal can be enhanced. The work mode of collaboration of multiple robotic fishes is adopted so that the detection area of the detectors can be extended and the overall work efficiency can be enhanced.

The invention provides a bionic robot fish of the family Trevally, belonging to the technical field of underwater robots, including a fish tail, a tail transmission mechanism, a tail steering gear, a battery, a controller, a pectoral fin steering gear, a switch and a fish body, and a pressure sensor , a sealing cylinder, an electronic compass, a buoyancy adjustment cylinder, a linear potentiometer, a buoyancy motor, a camera and a pectoral fin, the fish tail is connected with the tail steering gear through a tail transmission mechanism, a sealing cylinder and a buoyancy adjustment cylinder are arranged in the fish body, and the sealing cylinder A battery, a controller and a pectoral fin steering gear are arranged inside, a buoyancy motor is arranged at the rear end of the buoyancy adjustment cylinder, a switch and a camera are arranged on the head of the fish body. The beneficial effects of the present invention are: reasonable structure, novel and ingenious, capable of carrying a variety of information collection modules for data collection, at the same time adapting to the operation requirements in various environments, having good maneuverability and propulsion efficiency, and the modular design is easy to manufacture, Installation and commissioning simplifies the design and processing of complex parts and reduces costs.

The invention relates to the technical field of underwater bionic robots, in particular to a center-of-gravity regulating device. The invention discloses a center-of-gravity regulating device applied to an underwater robotic dolphin. A lead screw (1) is driven to rotate through the forward rotation and the backward rotation of a stepping motor (3) so as to move a lead screw nut (2) engaged with the lead screw (1); a slide block group is dragged to move forwards for realizing the movement of the center of gravity; an encoder (4) is used for recording the number of rotation circles and the angular speed of the lead screw (1) and estimating the position and the translation speed of the slide block group; and a front limit switch (11) and a back limit switch (12) are used for realizing the initial position resetting of the slide block group. The lead screw (1) and the stepping motor (3) of the center-of-gravity regulating device provided by the invention are subject to low radial load. Moreover, the center-of-gravity regulating device is simple in manufacture and convenient in control, can adapt to the center-of-gravity regulating demand for the three-dimensional movement of a larger robotic dolphin, and has a significant application prospect in the tasks of monitoring water quality environments, inspecting underwater equipment and the like.

The invention provides a robot recognition and target tracking system for an underwater robot, and belongs to the technical field of underwater robots. The system comprises an image collection module, an image processing module, a target recognition module, a target tracking module, a communication module, and a movement control module. The output end of the image collection module is connected with the input end of the image processing module. The image processing module enables the image feature information to be transmitted to the target recognition module and the target tracking module for the processing of an information instruction, and transmits the image feature information to the movement control module for the adjustment of the posture of the underwater robot through the communication module. The beneficial effects of the invention are that the system employs the technology of image recognition and tracking, can achieve the precise search, recognition, positioning and tracking of a target region, improves the controllability and environment adaptability of the underwater robot, reduces the working difficulty of an operator, and enables a miniature underwater robot to be carry out the precise observation and operation in a complex environment.

A metrology device, computer program product and computer-implemented method generating survey data without having the device touch subsea objects being surveyed. The metrology device may be used with an underwater vehicle or diving personnel, and may comprise an inertial navigation system having gyroscopes to detect angular velocity and accelerometers for the detection of linear velocity and transported by an underwater robotic apparatus or diver, the inertial navigation system outputting position and orientation data of the device for storage; an aiding device for collecting image data of the subsea objects, the aiding device being positioned so that the distance and orientation between the optical scanner and the inertial navigation system is known; and a computer for using the position information and image data between a successively visited known point to determine the drift of the metrology device and to use the drift of the metrology device to correct measurements of same.

The invention, which belongs to the technical field of the underwater robot, provides a wave power generation type underwater robot comprising a mother ship and a submersible vehicle. A solar panel, a storage battery and a generator are arranged at the mother ship; and the electric energy generated by the solar panel and the generator is stored into the storage battery. A rotor of the generator is connected with a spool wound with a cable by a coupler; a tension sensor is arranged below the spool; and the cable winding around the spool is connected with the submersible vehicle by passing through the tension sensor. The wave power generation type underwater robot has the following beneficial effects: the structure is reasonable and performances are stable; with a special transmission structure, the wave power can be converted into the electric power for an underwater submersible vehicle; on the basis of cooperation with the solar energy for power generation, energy conservation and environment protection are realized; local materials can be used, so that the working time of the underwater submersible vehicle can be extended; with underwater and water-surface dual detection devices, multiple functions of the underwater robot and the unmanned boat are realized; and the application range is large and performances are stable, and the underwater robot can be popularized and used conveniently.

The invention discloses a dish-shaped underwater vehicle based on vector propulsion, which relates to the technical field of a submersible and an underwater vehicle. Comprises an upper light housing (1) and a lower light housing (2) with a channel, and an aperture (5) for passing a searchlight and an optical fiber cable (3) is provided in the upper light housing (1); A hole for passing the camera4 is formed in the lower light housing 2; A low support plate 10 is mounted from bottom to top inside that the low light housing 2. 3. Middle support plate 1-2 with that upper support plate 10-1; Wherein the lower support plate 10-3 support that pressure chamber 12 and carry a camera 4; Middle support plate 10-2 are penetrated by that pressure-resistant chamber 12 and carry a vector propulsion device; Upper support plate 10-1 The searchlight 5 and the depth gauge 7 are mounted with corresponding holes for penetrating the watertight connector 16. The invention is applicable to the field of underwater observation operation by a remotely controlled underwater robot, including the military field, the scientific research field and the entertainment field.

The invention discloses a drifting detection underwater robot device and a control method, and belongs to the technical field of detection underwater robots. A robot main body is of a torpedo-shaped structure; hydrologic detection equipment ADCP (Acoustic Doppler Current Profiler), ranging sonar and an emergency load rejection device are carried at the fore body of a robot; a pressure-resistant cabin is arranged at a middle cabin section; the pressure-resistant cabin is divided into an energy source cabin and a control cabin; two high-energy density lithium batteries are arranged in the energysource cabin and are correspondingly used for supplying power to a power system and a control system; a conformal antenna (comprising Beidou positioning and communication, radio and WiFi), DVL, a depthometer and ranging sonar are carried at the tail section; high-efficiency propellers are arranged on the left side and the right side of the tail of the robot; and vertical channel propeller is arranged at each of the front and rear of the robot. According to the surrounding environment and task instructions of the robot, the effect of selecting to start or close a drifting mode is intelligentlyrealized, so that low-power-consumption, long-voyage and long-time detection monitoring tasks are realized.

The invention discloses a micro-miniature modularized AUV (autonomous underwater vehicle) and belongs to the technical field of underwater robots. The micro-miniature modularized AUV comprises a head segment, a channel segment, en energy segment, a communication navigation segment, a tail segment and a propelling segment, and further comprises a horizontal propeller, a longitudinal propeller, a charging hole, an antenna, a wing panel and a tail propeller, wherein the head segment, the channel segment, the energy segment, the communication navigation segment and the tail segment are in tight fitting through connecting pieces respectively, the channel segment is provided with two channel holes perpendicular to each other, the energy segment is provided with the charging hole, the antenna is arranged on the communication navigation segment through a supporting rod, and the propelling segment is arranged behind the tail segment. The micro-miniature modularized AUV has the advantages that the micro-miniature modularized AUV is light, low in manufacturing cost, practical, convenient and the like; by means of modularized design, structural interchange and electrical interconnection among modules can be achieved, and function combination and extension capabilities are improved to meet needs of various conditions; by the aid of reasonable propeller arrangement, flexible six-degree-of-freedom movement can be achieved.

The invention belongs to the technical field of underwater robots and particularly relates to an underwater robot dual-redundancy gesture detecting system. The underwater robot dual-redundancy gesture detecting system is composed of a data fusion processor, an MEMS attitude sensor, an electronic compass, a Doppler log, a depth meter and a height meter sensor, navigation calculation is achieved through a microcontroller, gestures, speed, depth and height information is output, an output interface of the Doppler log is connected to an input interface of the data fusion processor, an output interface of an electronic compass is connected to the input interface of the data fusion processor, and an output interface of the MEMS attitude sensor is connected to the input interface of the data fusion processor. The underwater robot dual-redundancy gesture detecting system adopts information provided by multiple types of navigation sensors and achieves a high-reliability navigation information output method through data fusion. An effective compensation method is designed by analyzing typical sea conditions, and the influence of outside interference and the shortcomings of the sensors on underwater robot gesture information is avoided.

The invention relates to an underwater robot technology, and aims to provide a vertical and horizontal attitude comprehensive adjusting device for an underwater glider. According to the vertical and horizontal attitude comprehensive adjusting device disclosed by the invention, baffle plates are respectively arranged on two sides of a battery bin; a central opening position of each baffle plate sleeves a corresponding nut through a double-row angular contact ball bearing; each nut is mounted on a corresponding screw rod; the gravity center position of the battery bin is lower than that of the screw rods; one end of each screw rod is fixed to a bin wall, and the other end of each screw rod is connected to an output shaft of a pitching motor through a corresponding shaft coupler; a rolling motor is mounted on one of the baffle plates, and an output end of the rolling motor is meshed with a driven gear on the corresponding baffle plate nut through a driving gear; the driven gear and the corresponding nut are relatively fixed, and relative rotating motion is not generated; one end of a guide rail parallel to the screw rods is fixed to the bin wall; and a sliding block is arranged on the guide rail, and is connected with a connecting piece fixed to the surface of the driven gear. According to the vertical and horizontal attitude comprehensive adjusting device disclosed by the invention, pitching gravity center adjustment is realized through utilizing a screw rod nut mechanism, and rolling gravity center adjustment is realized through utilizing a meshing gear set; and the vertical and horizontal attitude comprehensive adjusting device is simple in structure, convenient to arrange, low in space occupation, high in bin capacity utilization rate, good in control performance and high in adjusting ability.

The invention discloses a wheel-leg composite driving mechanism for an amphibious spherical robot, and belongs to the technical field of underwater robots. The wheel-leg composite driving mechanism comprises two or more mechanical legs distributed along the bottom of the spherical robot and a liftable sliding joint located at the bottom center of the spherical robot; when the liftable sliding joint rises, universal wheels at the bottom do not make contact with the ground, when the liftable sliding joint falls, the universal wheels at the bottom make contact with the ground, and the spherical robot is lifted to the preset height; and the four mechanical legs can move in the circumferential direction of the spherical robot and matched with the liftable sliding joint in a falling state to achieve sliding of the spherical robot, in addition, the four mechanical legs are matched with the liftable sliding joint in a rising state to achieve crawling of the spherical robot. The wheel-leg composite driving mechanism adopts different movement modes aiming at different terrain, and movement in the underwater environment, crawling of rugged road surfaces and sliding on flat road surfaces are achieved.

The invention belongs to the technical field of underwater robots, and particularly relates to an underwater robot six-degree-of-freedom dynamic positioning thrust distribution optimization method based on a genetic algorithm. The method comprises the following steps that the underwater robot working mode is determined according to the input quantity, a thrust distribution model is established, the complex constraint condition is simplified according to the spatial arrangement characteristics and genetic algorithm dimension reduction is realized; the size and the rotation angle of the propellers are set and the optimization objective is set; and the problem of thrust distribution optimization is solved by using the genetic algorithm, and the dimension reduction matrix is inversely solved so as to solve the thrust and the rotation angle of each propeller. The constraint of thrust distribution is enhanced to the six degree of freedom from the four degree of freedom; the problem of the difficulty of solving the nonlinear joint constraint of the conventional method can be avoided by using the genetic algorithm; and the dimension reduction method is put forward in thrust distribution and the solving accuracy can be enhanced and the calculation speed can be accelerated so that thrust distribution fast solving and optimization of energy consumption reduction under the condition of thesix-degree-of-freedom constraint can be realized.

The invention provides a microminiature full-freedom-degree cable-controlled underwater robot, and belongs to the technical field of underwater robots. The microminiature full-freedom-degree cable-controlled underwater robot comprises an upper floating body, a frame, an illuminating lamp I, a lower floating body, an illuminating lamp II, a control cabinet, a rear camera and a front camera. The microminiature full-freedom-degree cable-controlled underwater robot is characterized by also comprising an upper propulsion system and a lower propulsion system; the upper floating body is connected with the lower floating body through the frame; four through holes are formed in the surface of the upper floating body, and the upper propulsion system is arranged in the four through holes; the control cabinet is arranged in a middle position of a lower surface; and the lower propulsion system is arranged on the upper surface of the lower floating body. The microminiature full-freedom-degree cable-controlled underwater robot disclosed by the invention has the beneficial effects that an eight-propeller non-singular structure arranging form is adopted, so that full-freedom-degree control can be achieved, and the anti-jamming capability of a small-scale ROV is improved; the microminiature full-freedom-degree cable-controlled underwater robot adopts an image recognizing and tracking algorithm and an environment self-adaption intelligent control algorithm, so that the manoeuvrability of the ROV is greatly improved; and in addition, the microminiature full-freedom-degree cable-controlled underwater robot has the advantages of being small in size, light in mass, convenient to use, low in price and the like, and is convenient for market popularization and application.

The invention discloses a manta ray mode underwater robotic fish device and system. The manta ray mode underwater robotic fish device comprises a basal body, bionic manta ray pectoral fins, a propulsion assembly, and a bionic mantle membrane, wherein a camera cabin is arranged at the front end of the basal body, and an electronic cabin and a battery module cabin are arranged at the bottom of the basal body in parallel; the bionic manta ray pectoral fins are symmetrically arranged on the sides of the middle of the basal body and can swing up and down; the propulsion assembly is arranged at thetail part position of the basal body; and the bionic mantle membrane is attached to the bottom surface of the basal body. The manta ray mode underwater robotic fish device and system solve the problemthat an existing manta ray robotic fish cannot combine linear propulsion and flexible steering.

An improved inspection apparatus includes a control apparatus, a tractor apparatus comprising a tractor and a drive mechanism connected together, the drive mechanism being connected with the control apparatus, a tether apparatus disposed on the tractor and being movable between a deployed position and a retracted position, and a buoy apparatus. The buoy apparatus is connected with the tether apparatus and includes a buoy and a camera apparatus, the buoy in a condition submerged in a fluid applying a buoyant force to the camera apparatus whereby in the deployed position of the tether apparatus the buoy apparatus is in an elevated position situated relatively higher in a vertical direction than in the retracted position of the tether apparatus wherein the buoy apparatus is in another position situated relatively lower in the vertical direction, the camera apparatus being structured to provide a visual output signal to the control apparatus.