Patent Publication Number: US-2022236746-A1

Title: Thrust vectoring for fluid borne vehicles

Description:
TECHNICAL FIELD 
     The present application relates to thrust vectoring for fluid borne vehicles such as, for example, vehicles that use thrust vectoring to enable them to change their angular and/or linear velocities rapidly, and to decouple their trajectory from their body orientation. The present application is particularly relevant to aircraft, more particularly unmanned aerial vehicles (“UAVs”), unmanned submersible vehicle, remotely operated vehicles or drones. 
     BACKGROUND 
     A number of powered, fluid borne vehicles are known, including vehicles adapted to operate under the control of an onboard human pilot, as well as vehicles adapted to operate unmanned (being controlled either by an offboard human pilot, by onboard software, by offboard software, or by some combination of the above). Some such vehicles impart forces on the fluid medium through thrust producing means such as propellers and fans (also known as rotors), which accelerate the medium as they are rotated relative to the host vehicle by a driving means such as an electric motor or internal combustion engine. Examples of this type of vehicle include rotary wing and propeller driven fixed wing aircraft, submersibles (including submarines and underwater remotely operated vehicles (“ROVs”)) and airships. Other vehicles comprise thrust producing means wherein stored reaction matter is accelerated and ejected from the vehicle (for example, by burning a stored fuel and a stored oxidant, as in the case of rocket propelled vehicles). Further vehicles combine elements of these thrust producing means (for example, jet engine propelled vehicles, which burn stored fuel but predominantly accelerate ambient air ingested by the engines). Further to producing thrust, some thrust producing means also produce a moment (or torque) on the vehicle, and in many cases the production of thrust and the production of torque depend on each other. 
     Most powered, fluid borne vehicles control the forces and moments generated by their thrust producing means in order to control their motion through the fluid, using the thrust producing means directly to resist (or assist) gravity and/or to produce control forces and moments, or to ensure adequate relative flow of fluid about fluid dynamic surfaces affixed to the vehicle (for example, foils, wings or fins). A vehicle with prominent fluid dynamic surfaces typically generates large forces normal to these surfaces whilst largely controlling its orientation and trajectory by non-thrust producing means (for example, by actuating control surfaces such as flaps, ailerons or spoilers to influence the normal force on each fluid dynamic surface). 
     Powered, fluid-borne vehicles that rely heavily on direct control of the thrust producing means in order to generate control forces and moments may implement thrust vectoring, whereby both the orientations and the magnitudes of forces and moments produced by each thrust producing means are controlled by a vehicle control system, in order to directly produce a net force and moment on the vehicle and hence control its trajectory. 
     One example of such a fluid borne vehicle is the multi-rotor drone, a vehicle comprising a plurality of rotors typically arranged such that their axes of rotation are all substantially parallel to each other and said axes are in a substantially fixed relation to the vehicle. Such a vehicle vectors the forces and moments generated by the rotors by varying the speed of rotation of each rotor independently (causing a change in the thrust and moment applied to the vehicle by each rotor). By so varying the force and moment applied to the vehicle by each rotor, the vehicle changes its orientation, thereby changing the direction in which the net thrust from the rotors acts, and so controls its trajectory. 
     A disadvantage of a vehicle such as the multi-rotor drone described above is that the orientation of the vehicle (and any payloads affixed directly to the vehicle, such as sensors or effectors) is coupled to the vehicle&#39;s trajectory, which is undesirable when a payload needs to be aimed dynamically. A common solution that at least partially decouples the orientation of a payload item from the orientation (and trajectory) of the vehicle is the introduction of a motorised gimbal between the vehicle and the payload. However, such a gimbal adds weight, and cannot typically compensate for the complete range of vehicle orientations due to body masking and mechanical constraints on gimbal rotation. As a result, significant performance and agility can be sacrificed, especially when the payload is elongate (for example, a tube-shaped projectile launcher) or otherwise of a high mass and inertia (necessitating a heavy gimbal). This significantly degrades the mission capability of such vehicles in tasks requiring high agility and performance whilst simultaneously aiming payloads independently of the vehicle&#39;s trajectory. 
     A further consequence of the coupling between the vehicle&#39;s orientation and the net force vector is that the inertia of the entire vehicle affects the speed with which the vehicle can modify said vector. Typically, a multi-rotor drone comprises significant structural mass, as well as the mass of batteries and onboard systems required for flight. The inertia of this combined mass impedes the ability of the control system to quickly modify the net force vector, for example to counter external disturbances such as wind gusts. This hampers the ability of such a vehicle to operate in windy environments. 
     A further disadvantage of the coupling between the vehicle&#39;s orientation and the net force vector with respect to multi-rotor drones is that, in order to move horizontally, a drone will typically adopt a high drag configuration relative to its direction of motion, reducing its ability to achieve a high speed. 
     Rotating the axis of rotation of each rotor of a multi-rotor drone (each about an axis radiating substantially from the centre of the drone and passing close to the axis of rotation of the rotor) is a known method of decoupling such a vehicle&#39;s trajectory from its orientation, and also of potentially improving the speed of response to disturbances (see Kamel, M., Verling, S., Elkhatib, O., Sprecher, C., Wulkop, P., Taylor, Z., Siegwart, R. and Gilitschenski, I., 2018. Voliro: An omnidirectional hexacopter with tiltable rotors. arXiv preprint arXiv:1801.04581). 
     In this approach, however, it is difficult to efficiently apply large forces in any configuration apart from the configuration in which all the rotor axes of rotation are substantially parallel (as for a conventional multi-rotor drone). Accordingly, decoupling of the vehicle&#39;s trajectory and orientation still incurs a significant cost in performance and agility. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example implementations will now be described, by way of example only, referring to the accompany drawings. 
         FIG. 1  is a perspective view of an unmanned aerial vehicle according to example implementations. 
         FIG. 2  is a detailed view of thrust vectoring module(s) according to example implementations. 
         FIG. 3  is a perspective view of the vehicle with its thrust vectoring modules configured to propel the vehicle forwards according to example implementations. 
         FIG. 4  is a perspective view of the vehicle with its thrust vectoring modules configured to yaw the vehicle according to example implementations. 
         FIG. 5  is a perspective view of the vehicle hovering with its body oriented at an extreme pitch angle according to example implementations. 
         FIG. 6  is a perspective view of the vehicle with its thrust vectoring modules configured for an extreme manoeuvre according to example implementations. 
         FIG. 7  is a perspective view of the vehicle configured to hover with the body in a vertical orientation and with the exhaust from the thrust producing means of one thrust vectoring module impinging on the thrust producing means of a second thrust vectoring module according to example implementations. 
         FIG. 8  is a perspective view of the vehicle configured to hover with the body in a vertical orientation and with the exhaust from the thrust producing means of one thrust vectoring module not impinging on the thrust producing means of a second thrust vectoring module according to example implementations. 
         FIG. 9  is a detailed view of a thrust producing means of a thrust vectoring module whereby an axis of rotation of the thrust producing means is controlled by an actuator according to example implementations. 
         FIG. 10  is a diagram showing a plan view of an arrangement of three thrust vectoring modules affixed to an elongate body according to example implementations. 
         FIG. 11  is a diagram showing a plan view of an arrangement of three thrust vectoring modules affixed to a ‘Y’ shaped body according to example implementations. 
         FIG. 12  is a diagram showing a plan view of a vehicle comprising two thrust vectoring modules, wherein each module comprises a pair of thrust producing means, each thrust producing means disposed on either side of an elongate body according to example implementations. 
         FIG. 13  is a diagram showing a plan view of a vehicle according to example implementations, wherein each thrust vectoring module comprises two quartets of thrust producing means, such that individual control of the thrust producing means is sufficient (without additional actuation) to control the net force and moment applied to the vehicle by a thrust vectoring module. 
         FIG. 14  is a diagram showing plan views of thrust vectoring modules according to example implementations. 
         FIG. 15  is a diagram showing plan views of further thrust vectoring modules according to example implementations. 
         FIG. 16  depicts a thrust vectoring module according to example implementations. 
         FIG. 17  illustrates balanced torque and thrust differentials according to example implementations. 
         FIG. 18  depicts a flight controller according to example implementations. 
         FIG. 19  illustrates machine-readable storage and machine-executable instructions according to example implementations. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , shown is an example implementation of an unmanned aerial vehicle  100 . The vehicle  100  is shown with axes ‘x’, ‘y’, and ‘z’ that will be used in the forthcoming description. The vehicle  100  has a vehicle body  102  that extends generally along the ‘x’ axis and has a centre of gravity (COG)  104 . The vehicle  100  has a longitudinal axis  106 . 
     The vehicle  100  has two arms  108 ,  110  rotatably attached to the vehicle body  102  at a distance along the ‘x’ axis from the COG  104  at arm mounting points  112 ,  113 . The two arms  108 ,  110  are each able to rotate relative to the vehicle body  102  about respective axes of rotation  114 ,  116 . The rotation of the arms  108 ,  110  may be limited, or the arms may be able to rotate continuously, that is, freely without any rotational limit. The rotation of one or both arms  108 ,  110  may be controlled by respective independent actuators that are described below with reference to  FIG. 9 . Additionally, or alternatively, one arm, or both of the arms  108 ,  110 , may be free to rotate in a bearing with the rotation being controlled by controlling the moments acting on an arm due to at least one of one or more forces or one or more moments from thrust producing means  118 ′,  118 ″. It will be appreciated that such one or more moments will have an effect when one or more than one of the bars  122  to  128  are rotated. The mounting point  112  of one arm is located a distance from the vehicle COG along the ‘x’ axis in one direction while the mounting point  113  of the other arm is located a distance from the vehicle COG along the ‘x’ axis in the opposite direction. 
     Example implementations can be realised in which the thrust producing means comprises one or more than one of a thruster such as, for example, a rotor such as any of the propellers  120  depicted. The thrust producing means may additionally comprise one or more than one motor. A motor can be provided per rotor. 
     Each arm  108 ,  110  has rotatably attached thereto a pair of thrust producing means mounting bars  122  to  128 . In the example implementation shown, the mounting bars  122  to  128  are rotatable relative to their respective arms  108 ,  110  about respective mounting bar axes  130  to  136  of rotation. The mounting bars  122  to  128  to are each mounted at mounting points  138  to  144  along the arms  108 ,  110 . The mounting points  138  to  144  are displaced a distance along the respective arm rotation axes  114 ,  116  from the arm mounting point  112 ,  113  of their respective arms  108 ,  110 . For each arm  108 ,  110 , one mounting bar is displaced a distance along the arm rotation axis in one direction and the other in the opposite direction. The rotation of each bar about a respective rotational axis  130  to  136  may be controlled by an appropriate actuator including through the use of one or more further (not shown) thrust producing means. 
     Each of the mounting bars  122  to  128  has attached thereto one or more thrust producing means  118 ′,  118 ″. Example implementations will be described in which each mounting bar  122  to  128  has an equal number of thrust producing means. Furthermore, example implementations will be described in which each mounting bar  122  to  128  comprises respective pluralities of thrust producing means  118 ′,  118 ″ such as, for example, the respective pairs of thrust producing means  118 ′,  118 ″ depicted. The thrust producing means  118 ′,  118 ″ are each mounted a distance from respective bar mounting points  138  to  144  along respective axes of rotation  130  to  136 . Example implementations can be realised in which one, or a first, thrust producing means  118 ′ of each bar is displaced from a respective bar mounting point along a respective mounting bar axis of rotation in one direction and the other thrust producing means  118 ″ is displaced in the opposite direction. 
     A thrust vectoring module  146  to  152  comprises a set of arms, set of thrust producing means mounting bars, and a set of thrust producing means. It will be appreciated from the above description that each thrust vectoring module  146  to  152  can be rotated about an axis parallel to the vehicle body ‘y’ axis by rotating the arm  108 ,  110  of said thrust vectoring module about its rotational axis. Furthermore, each thrust producing means  118 ′,  118 ″ can be rotated about an axis not parallel to a respective arm rotational axis  114 ,  116  by rotating the corresponding thrust producing means mounting bar  112  to  128  about a respective rotational axis  130  to  136 . A thrust vectoring module  146  to  152  is an example implementation of a thrust vectoring assembly. As will be appreciated below, particularly with reference to  FIG. 12 , a thrust vectoring module can comprise at least one thrust producing means mounted on a respective bar rotatably coupled to a respective arm. 
     The vehicle  100  is shown in  FIG. 1  in a hovering position with the body  102  of the vehicle in a horizontal position. In this position, the vehicle  100  can be rotated and stabilised about the body ‘x’ axis by differing the thrust provided by each thrust producing means  118 ′,  118 ″. 
     The vehicle  100  can be rotated and stabilised about the body ‘y’ axis by differing the forces produced by the two arms  108 ,  110  about this axis. With the arms  108 ,  110  in the positions shown in  FIG. 1 , the vehicle  100  can thus be rotated and stabilised about the body ‘y’ axis by differing the net forces produced by thrust producing means  118 ′,  118 ″ of the rear thrust vectoring modules  148  and  152  relative to that produced by thrust producing means associated with the front thrust vectoring modules  146  and  150 . 
     The vehicle can be rotated and stabilised about the body ‘z’ axis by rotating one or more of the mounting bars  122  to  128  mounted on, or at the ends of, each arm  108 ,  110  into positions in which the forces produced from the thrust producing means  118 ′,  118 ″ mounted on, or at the ends of, each bar have a component perpendicular to the body ‘z’ axis. Such an arrangement is shown in  FIG. 4 , where all four mounting bars  122  to  128  shown have been rotated so that the forces produced from the thrust producing means  118 ′,  118 ″ attached thereto create moments about the body ‘z’ axis. It will be appreciated that it is not necessary to rotate all the mounting bars  122  to  128  to control the vehicle  100  about the body ‘z’ axis. It will be appreciated that the vehicle can alternatively be rotated and stabilised about the body ‘z’ axis through applying a torque differential to counter rotating pairs of rotors of a rotary thrust producing means  118 ′,  118 ″ in arrangements using rotary thrust producing means  118 ′,  118 ″. The thrust vectoring approach described herein may provide faster response times and/or larger moments. 
     In the example implementations described herein the thrust producing means can be controlled individually and independently of one another in any and all permutations. The control of the thrust producing means comprises control over at least one or more than one of the speed of the rotors  120 , the rotation of at least one arm or both of the arms  108 ,  110 , or at least one or more than one of rotation of the mounting bars  122  to  128 , all taken jointly and severally in any and all permutations. Similarly, rotations of an arm  108 ,  110  can be individually and independently controlled. Also, rotations of the mounting bars  122  to  128  can be individually and independently controlled. Still further, example implementations can be realised in which the rotors  120  have at least one, or both, of cyclic or collective pitch control that can all be controlled individually and independently. Still further any and all example implementations can be realised in which the thrust producing means  118 ′,  118 ″ can be formed into one or more than one set of thrust producing means  118 ′,  118 ″ such that the thrust producing means  118 ′,  118 ″ within a set can be controlled individually and independently of any other thrust producing means outside of the set, and/or in which the thrust producing means within a set can be controlled synchronously with one another. For example, the thrust producing means within a set can all be controlled to vary respective thrusts by a given percentage, or to adopt a prescribed thrust. 
     In example implementations herein the two arms  108 ,  110  are free to rotate relative to the vehicle body  102  as a result of the moments acting about their respective rotational axes  114 ,  116 . In such an embodiment, the rotation of each arm  108 ,  110  relative to the vehicle body  102  must be controlled. This can be achieved by differing or otherwise varying the net thrust provided by the thrust producing means  118 ′,  118 ″ mounted on opposing ends of the mounting bars such as, for example, ensuring that thrust producing means  118 ′ on the end of mounting bar  122  has a different thrust to thrust producing means  118 ″ on the other end of the mounting bar  112 . It will be appreciated that by having such a thrust differential between opposing thrust producing means pairs, at least one, or both, of the rotational position or angular rates of rotation of the arms  108 ,  110  relative to the body  100  can be controlled. 
     It will be appreciated that by rotating the arms  108 ,  110  to a desired angle relative to the vehicle body  102 , the force/moment vector produced from the thrust producing means  118 ′,  118 ″ associated with each arm can be rotated about an axis parallel to the vehicle body ‘y’ axis of the vehicle  100  without rotating the vehicle body  102  about the ‘y’ axis. 
     It will be further appreciated that, in relation to a thrust vectoring module  146  to  152 , provision may be made for one or more than one thrust producing means mounting bar on one side of the main body  102  to rotate independently about the arm axis of rotation relative to the mounting bar on the other side of the main body  102  by, for example, fixing the rotation of the arm relative to the body and introducing a separate bearing for each mounting bar to enable its independent rotation about the arm axis, or by splitting the arm in two at some point along its length). It will be further appreciated that in such an arrangement the rotation of a mounting bar on one side of the main body can be effected independently of the other side by a separate actuator for each mounting bar, or by independently controlling the moments about the mounting bar axis acting on each mounting arm by at least one or more forces or one or more moments, or a combination of one or more forces and one or more moments from the thrust producing means  118 ′,  118 ″ mounted to each arm. It will be further appreciated that if such a provision is made, the axes of rotation of each, or one or more than one, mounting bar may not be aligned. It will be further appreciated that a provision for such independent rotation of the mounting bars about the arm axis may optionally remove the requirement to rotate the mounting bars about their respective mounting bar axes in order to control the vehicle, as, for example, the differential from the thrust vectors from thrust producing means  118 ′,  118 ″ on opposing arms can be used to control the vehicle about its ‘z’ axis when the vehicle is in the orientation of  FIG. 1 . 
     Referring to  FIG. 2 , there is shown a close up view  200  of a thrust vectoring module. Example implementations of a thrust vectoring module can be varied.  FIG. 2  illustrates several configurations of thrust vectoring modules; namely thrust vectoring module  202 , thrust vectoring module  214  and thrust vectoring module  216 . The thrust vectoring modules  202 ,  214 ,  216  are example implementations of one or more than one or all of the above described thrust vectoring modules  146  to  152 . The thrust vectoring module  202  comprises a number of thrust producing means  204  to  210 . The thrust producing means  204  to  210  are example implementations of the above described thrust producing means  118 ′.  118 ″. In the example implementation depicted, the thrust vectoring module  202  comprises a number of thrust producing means disposed either side of the body  100 , or at distal ends or positions of an arm  212 , or arms  212 ′,  212 ″. The arm  212  is, or the arms  212 ′,  212 ″ are, an example of one or both of the arms  108 ,  110  described above. In the example shown, the thrust vectoring module  202  comprises four thrust producing means  204  to  210 . The four thrust producing means  204  to  210  are positioned either side of the body  100 . Alternatively or additionally, as indicated above, a thrust vectoring module can comprise a set of thrust producing means disposed on the same side of the body  100 , or at the same end of the arm  212 , in the same manner as the thrust vectoring modules  146  to  152  described above.  FIG. 2  illustrates two such thrust vectoring modules  214 ,  216 . Example implementations can be realised in which each thrust producing means  118 ′,  118 ″ comprises a respective motor  218  to  224 . The motors  218  to  224  can be controlled independently of one another, or can be controlled in synchronisation with one another. The thrust vectoring module  202 , or the thrust vectoring modules  214 ,  216 , have respective arms  212 ′,  212 ″ with a common arm axis  226 . The arm axis  226  is an example of any or all of the arm axes  114 ,  116  described above. Similarly, the thrust vectoring module  202  has, or the thrust vectoring modules  214 ,  216  have, have respective mounting bars  228 ,  230 . The mounting bars are examples of the mounting bars  122  to  128  described above. Each mounting bar  228 ,  230  has a respective mounting bar axis  232 ,  234 , which is comparable to the above described mounting bar axes  130  to  136 . 
     Referring to  FIG. 3  shows a view  300  of an arrangement demonstrating decoupling of the thrust vector from the vehicle body orientation. From the arrangement shown in  FIG. 1 , the vehicle  100  can be translated by tilting the entire vehicle  100 , including the thrust vectoring modules  146  to  152 , together in order to direct the resultant thrust vector acting on the vehicle body  102 . In the arrangement of  FIG. 3 , the vehicle body  102  is maintained in a horizontal orientation, or any other orientation, while the net thrust from the thrust vectoring modules  146  to  152  acts to propel the vehicle  100  forward. This may, for example, allow a sensor or payload  302  that is incorporated into the vehicle body or rigidly attached thereto to maintain a horizontal, or other, orientation while the vehicle moves in a desired direction and/or accelerates at a desired rate. Furthermore, this arrangement may allow the vehicle to accelerate with a faster response time than the aforementioned alternative of  FIG. 1  since the thrust producing means  118 ′,  118 ″ are not required to rotate the entirety of the vehicle  100  to the desired orientation, but rather only need to rotate the thrust vectoring modules  146  to  152 . This can follow from the thrust vectoring modules have a lower moment of inertia as compared to the vehicle body, or vehicle as a whole. In this way, example implementations can be realised in which the attitude of the vehicle body  102  can be set, maintained or changed, independently of the orientation of the thrust vectoring modules  146  to  152 , the angle of rotation or inclination of at least one, or both, of the mounting bar axes of rotation  130  to  136  or the arm axes of rotation  114 ,  116  taken jointly and severally in any and all permutations. 
     Referring to  FIG. 4 , there is shown a view  400  of the vehicle  100  of  FIG. 1  in an arrangement in which thrust producing means mounting bars  122  to  128  have been rotated through an angle relative to the arms  108 ,  110  to which they are attached. This can be used to control vehicle  100  rotation about the vehicle body ‘z’ axis. In the example depicted, the front two mounting bars  122 ,  126  have been rotated to a position of 45 degrees while the rear two mounting bars  124 ,  128  have been rotated to a position of 135 degrees. Although the example illustrated has been described with reference to pairs of mounting bars; namely bars  122 ,  126  and bars  124 ,  128 , having been rotated to the same position, example implementations are not limited to such an arrangement. Example implementations can be realised in which each mounting bar  122  to  128  can be rotated to the same position as any other mounting bar  122  to  128  or can be rotated to a respective, individual or different, position as compared to any other mounting bar  122  to  128 . 
     Referring to  FIG. 5 , there is shown a view  500  of the vehicle  100  of  FIG. 1  in an arrangement in which each arm  108 ,  110  has been rotated through an angle relative to the vehicle body  102  and the vehicle body  102  has been rotated at an angle relative to the horizontal position of  FIG. 1 . In this arrangement, the decoupling of the thrust vector from the vehicle body orientation allows the vehicle body  102  to be maintained in a desired non-horizontal orientation while the thrust vectoring modules  146  to  152  are oriented such that the vehicle  100  can maintain a static hover or move in any direction, and/or give effect to any rotation, while maintaining the depicted vehicle body attitude. 
     It will be appreciated therefore that example implementations allow the vehicle body ‘x’ axis to attain desired directions while simultaneously independently applying a net thrust to the vehicle body to control desired translations and while simultaneously controlling the vehicle body  102  about its ‘y’ and ‘z’ axes. Example implementations can be realised in which any given vehicle body axis can assume a desired attitude while concurrently controlling or moving the vehicle body about any one or more other vehicles axes. 
       FIG. 6  shows a view  600  of an example implementation of a position in which the vehicle body ‘x’ axis is oriented vertically. The thrust vectoring modules  146  to  152  can produce moments about all of the axes depending on the operation of the thrust producing means. A possible configuration of the thrust producing means, given the orientation of the thrust vectoring modules, would be a corkscrew or helical motion about the ‘y’ axis together with modulating, in time, the thrust from each thrust producing means to maintain the vehicle air borne. In such an arrangement the vehicle  100  can be controlled by rotating the arms  108 ,  110  of the thrust vectoring modules  146  to  152  relative to the body  102 . It will be appreciated that the control scheme about the vehicle body ‘y’ axis as described with reference to  FIG. 1  and that described with reference to  FIG. 6  can, for example, be used, in combination or alternatively, to control the vehicle about its body ‘y’ axis over a range of positions. 
     Referring to  FIG. 7 , there is shown a view  700  of the vehicle  100  vertically disposed. With the thrust vectoring modules  146  to  152  positioned as indicated, that is, the mounting bar axes of rotation  130  to  136  being perpendicular or orthogonal to the longitudinal axis  106  of the vehicle body  102 , the vehicle  100  can hover, ascend or descend vertically. In such an arrangement, the net thrust differential between each of the thrust vectoring modules  146  to  152  cannot be used to control the vehicle body  102  about its ‘y’ axis without first causing their respective arms to rotate about their respective arm axes  114 ,  116  as these thrust vectors have no moment arm about the ‘y’ axis in the instantaneous configuration shown. 
     In example implementations the arms  108 ,  110  are free to rotate continuously relative to the vehicle body  102  about their rotation axis  114 ,  116 . Thus, it will be appreciated that the vehicle body  102  can, for example, be rotated continuously while the vehicle remains in a hover with a static COG. 
       FIG. 8  shows a view  800  of an arrangement that describes further aspects of example implementations. In the arrangement of  FIG. 7 , the thrust vectoring modules  146  to  152  are rotated to a position in which one or more of the thrust producing means  118 ′,  118 ″ of one thrust vectoring module such as, for example, one, or both, of thrust vectoring modules  148 ,  152 , impinges on, or otherwise interferers with or influences, a thrust producing means  118 ′,  118 ″ of another thrust vectoring module such as one, or both, of thrust vectoring modules  146 ,  150 . Example implementations can be realised in which at least one, both or more, of the thrust vectoring modules or thrust producing means  118 ′,  118 ″ can be positioned or oriented to at least reduce or eliminate such impingement, interference or influence. In the example depicted in  FIG. 7 , it can be seen that the thrust producing means  118 ′,  118 ″ of the upper thrust vectoring module or modules  148 ,  152  are, in this position, propelling fluid directly towards the thrust producing means  118 ′,  118 ″ of the lower thrust vectoring module or modules  146 ,  150 . It will be appreciated that this can have undesirable effects on the thrust produced from the thrust producing means  118 ′,  118 ″ of the lower thrust vectoring module or modules  146 ,  150 . Therefore, example implementations allow the thrust producing means  118 ′,  118 ″ of the upper thrust vectoring module or modules  148 ,  152  to be rotated as shown in  FIG. 8  by rotating the mounting bars  124 ,  128 . The thrust producing means  118 ′,  118 ″ are operated such that the net thrust of each, in at least one, or both, of the ‘y’ or ‘z’ axis direction, balance or otherwise cancel, that is, without introducing a net moment or force acting on the vehicle body in the ‘yz’ plane. This alleviates, or at least reduces, problematical interference between the thrust vectoring modules without introducing a net moment or force acting on the vehicle body. 
       FIG. 9  shows a pair of views  900  of an example mechanism  902  to rotate mounting bars  122  to  128 . The example mechanism  902  is an example implementation of an actuator such as any of the actuators described herein. The rotor, that is, the thrust producing means  118 ′,  118 ″ is mounted on a mounting bar  904 . The mounting bar  904  is an example implementation of any of the mounting bars  122  to  128  described herein. The thrust producing means  118 ′,  118 ″ is rotatably coupled, via a number of linkages  906  to  910 . A first linkage  906  is driven by, or coupled to, a servomotor  912 . The servomotor  912  controls the rotation and orientation of the thrust producing means  118 ′,  118 ″ by rotating the first linkage  906  that, in turn, rotates the thrust producing means  118 ′,  118 ″. The linkages are arranged to control rotation of the thrust producing means about a respective mounting bar axis. It will be appreciated that but for the thrust producing means being distally disposed from a respective arm, there would be mechanical interference between a rotor of the thrust producing means and the respective arm. 
       FIG. 10  shows a view  1000  of an alternative example implementation of a vehicle  1002  comprising a number of thrust vectoring modules. In the example illustrated there are three thrust vectoring modules  1004  to  1008  arranged linearly along a vehicle body  1010 . The vehicle  1002  is an example of any of the vehicles described herein such as, for example, the above described vehicle  100 . Similarly, the thrust vectoring modules  1004  to  1008  are examples of any of the thrust vectoring modules described herein such as, for example, thrust vectoring modules  146  to  152  and/or the thrust vectoring module  202  or modules  214 ,  216  described with reference to  FIG. 2 . Although the example illustrated comprises three thrust vectoring modules, example implementations are not limited to such an arrangement. Example implementations can be realised in which there are one, two, three or more than three thrust vectoring modules. 
       FIG. 11  shows a view  1100  of an alternative example implementation of a vehicle  1102  in which there are a plurality of thrust vectoring modules arranged on a vehicle body  1104 . In the example depicted, the vehicle comprises three thrust vectoring modules  1106  to  1110  arranged on a vehicle body  1104 . The vehicle  1102  is an example of any of the vehicles described herein such as, for example, the above described vehicle  100 . Similarly, the thrust vectoring modules  1106  to  1110  are examples of any of the thrust vectoring modules described herein such as, for example, thrust vectoring modules  146  to  152  and/or the thrust vectoring module or modules  202 ,  214 ,  216  described with reference to  FIG. 2 . Although the example depicted comprises three thrust vectoring modules, example implementations are not limited to such an arrangement. Example implementations can be realised in which there are one, two, three or more than three thrust vectoring modules. 
       FIG. 12  shows a view  1200  of an alternative example implementation of a vehicle  1202  in which each mounting bar  1204  to  1210  has only a single thrust producing means  1212  to  1218  attached thereto. Such an arrangement does not allow the angle of each arm  1220  to  1230  to be controlled by the differential thrust between two thrust producing means as does the arrangement shown in the preceding figures. As such, the angle is controlled using an actuator. Example implementations of the actuator can be realised as described above in  FIG. 9 . Such an arrangement may use fewer thrust producing means  1212  to  1218  than the arrangement shown in, for example,  FIG. 1 . Such an arrangement may use a larger number of non-thrust producing actuators and may have a greater response time than the example implementations described with reference to  FIG. 1 . 
     The vehicle  1202  is an example of any of the vehicles described herein such as, for example, the above described vehicle  100 . Similarly, the thrust producing means  1212  to  1218  are examples of any of the thrust producing means described herein such as, for example, thrust producing means  204  to  210  described with reference to  FIG. 2 . Although the example depicted comprises two thrust vectoring modules, example implementations are not limited to such an arrangement. Example implementations can be realised in which there are one, two or more than two thrust vectoring modules. 
       FIG. 13  shows a view  1300  of an alternative example implementation of a vehicle  1302  in which each mounting bar  1304  to  1310  has a plurality of thrust producing means. In the example shown, the vehicle  1302  comprises four thrust vectoring modules  1312  to  1318  attached thereto. Such an arrangement allows the angles of the mounting bars  1304  to  1310  to be controlled with thrust differentials in a manner analogous to that with which the angle of the arms is controlled in various implementations described herein. Such an arrangement may use fewer non-thrust producing actuators than the arrangement shown in, for example,  FIG. 1 . Such an arrangement may use a larger number of thrust producing means  1312  to  1318 . 
     The vehicle  1302  is an example of any of the vehicles described herein such as, for example, the above described vehicle  100 . Similarly, the thrust vectoring modules  1312  to  1318  are examples of any of the thrust vectoring modules described herein such as, for example, thrust vectoring modules  146  to  152  and/or the thrust vectoring module or modules  202 ,  214 ,  216  described with reference to  FIG. 2 . Although the example depicted comprises four thrust vectoring modules, example implementations are not limited to such an arrangement. Example implementations can be realised in which there are one, two, three, four or more than four thrust vectoring modules. 
     It will be appreciated that where the rotation of the arms and/or mounting bars are controlled by actuators, it may be possible to use differential thrust to apply moments about the rotational axes, which may, for example, allow control of the vehicle body about an axis without rotation of one or more of the arms or mounting bars. 
       FIGS. 14A-D  shows views  1400  of example implementations of thrust vectoring modules. 
       FIG. 14A  shows a view  1400 A of an example implementation in which a thrust vectoring module  1402 A is rotatably attached to a vehicle body at a mounting point  1404 A via a rotatable arm  1406 A. The thrust vectoring module has a number of thrust producing means. In the example shown, the thrust vectoring module  1402 A comprises two thrust producing means  1408 A,  1410 A attached to a mounting bar  1412 A. Rotation of the arm  1406 A about a respective rotation axis  1414 A is controlled using at least one of differential thrusts or differential moments between the two thrust producing means  1408 A,  1410 A. 
       FIG. 14B  depicts a view  1400 B of an example implementation in which a thrust vectoring module  1402 B is rotatably attached to a vehicle body at a mounting point  1404 B via a rotatable arm  1406 B. The thrust vectoring module  1402 B comprises a plurality of thrust producing means. In the example depicted, the thrust vectoring module  1402 B comprises two thrust producing means  1408 B,  1410 B attached to a mounting bar  1412 B. Rotation of the arm  1406 B about a respective rotation axis  1414 B is controlled using at least one of differential thrusts or differential moments between two thrust producing means  1408 B,  1410 B. Rotation of the mounting bar  1412 B can also be effected about a further rotation axis  1416 B. The rotation of the mounting bar  1412 B about the further axis of rotation  1416 B can be effected using an actuator. 
       FIG. 14C  shows a view  1400 C of an example implementation in which a thrust vectoring module  1402 C is rotatably attached to a vehicle body at a mounting point  1404 C via a rotatable arm  1406 C. The thrust vectoring module  1402 C comprises a predetermined number of thrust producing means. In the example implementation shown, the thrust vectoring module  1402 C comprises four thrust producing means  1408 C,  1410 C′,  1408 C,  1410 C′, two attached to each of two mounting bars  1412 C,  1412 C′ attached along the arm  1406 C rotation axis on either side of the mounting point  1404 C. Rotation of the arm  1406 C about a respective rotation axis  1414 C is controlled using at least one of differential thrusts or differential moments between thrust producing means  1408 C,  1410 C,  1408 C′,  1410 C′. 
       FIG. 14D  shows a view  1400 D of an example implementation in which a thrust vectoring module  1402 D is rotatably attached to a vehicle body at a mounting point  1404 D via a rotatable arm  1406 D. The thrust vectoring modules  1402 D comprises a predetermined number of thrust producing means. In the example implementation shown, the thrust vectoring module  1402 D comprises four thrust producing means  1408 D,  1410 D,  1408 D′,  1410 D′; two attached to each of two mounting bars  1412 D,  1412 D′ attached along the arm rotation axis  1414 D on either side of the mounting point  1404 D wherein the rotation of the arm  1406 D about its rotation axis  1414 D is controlled using at least one of differential thrusts or differential moments between thrust producing means  1408 D,  1410 D,  1408 D′,  1410 D′ and wherein the mounting bars  1412 D,  1412 D′ are controllably rotatable about at least one or more further rotation axis or axes  1416 D,  1416 D′. The rotation of the mounting bars  1412 C or  1412 C′ about the rotation axis or axes  1416 D,  1416 D′ can be effected using an actuator. 
     The vehicles depicted in  FIG. 14  are examples of any of the vehicles described herein such as, for example, the above described vehicle  100 . Similarly, the thrust vectoring modules  1402 A-D are examples of any of the thrust vectoring modules described herein such as, for example, thrust vectoring modules  146  to  152  and/or the thrust vectoring module or modules  202 ,  214 ,  216  described with reference to  FIG. 2 . Although the examples shown comprise a given number of thrust vectoring modules, example implementations are not limited to such arrangements. Example implementations can be realised in which there are one, two, three, four or more than four thrust vectoring modules. 
       FIGS. 15A and 15B  show views  1500  of example implementations of thrust vectoring modules. 
       FIG. 15A  shows a view  1500 A of an example implementation in which a thrust vectoring module  1502 A is rotatably attached to a vehicle body at a mounting point  1504 A via a rotatable arm  1506 A. The thrust vectoring module  1502 D comprises a predetermined number of thrust producing means. In the example implementation illustrated, the thrust vectoring module  1502 A has four thrust producing means  1508 A,  1510 A,  1508 A′,  1510 A′ attached to a mounting bar  1512 A. Rotation of the arm  1506 A about a respective rotation axis  1514 A is controlled using at least one of differential thrusts or differential moments between thrust producing means  1508 A,  1510 A,  1508 A′,  1510 A′, and wherein the mounting bar  1512 A is controllably rotatable about a further rotation axis  1516 A using at least one of differential thrusts or differential moments between thrust producing means  1508 A,  1510 A,  1508 A′,  1510 A′ or selected subsets of the thrust producing means  1508 A,  1510 A,  1508 A′,  1510 A′ and/or an actuator to rotate the mounting bar  1512 A. 
       FIG. 15B  shows a view  1500 B of an example implementation in which a thrust vectoring module  1502 B is rotatably attached to a vehicle body at a mounting point  1504 B via a rotatable arm  1506 B. The thrust vectoring module  1502 B comprises a predetermined number of thrust producing means. In the example implementation shown, the thrust vectoring module  1502 B has eight thrust producing means  1508 B,  1510 B to  1508 B″′,  1510 B″′, four of which are attached to each of two mounting bars  1512 B,  1512 B′. Rotation of the arm  1506 B about a respective rotation axis  1514 B is controlled using at least one of differential thrusts or differential moments between thrust producing means  1508 B,  1510 B to  1508 B″&#39;,  1510 B″′, and wherein the mounting bars  1512 B,  1512 B′ are each controllably rotatable about further rotation axes  1516 B,  1516 B′ using at least one of differential thrusts or differential moments between thrust producing means  1508 B,  1510 B to  1508 B″′,  1510 B″′, or selected subsets of the thrust producing means  1508 B,  1510 B to  1508 B″′,  1510 B″′. 
     Referring to  FIG. 16 , there is shown a view  1600  of a thrust vectoring module  1602  comprising an arm  1604  having an arm axis  1606 . The arm  1604  can be mounted or otherwise rotatably coupled to a vehicle body  1608 . The arm  1604  has a number of mounting bars. In the example implementation shown the arm  1604  has two mounting bars  1610 ,  1612 . However, example implementations are not limited to such an arrangement. Example implementations can be realised in which the arm  1604  has two or more mounting bars. 
     Each mounting bar  1610 ,  1612  bears a set of thrust producing means. In the example shown, each mounting bar has a respective plurality of thrust producing means. The example implementation depicted comprises a pair of thrust producing means  1614 ,  1616  disposed on the mounting bar  1610  proximal to the vehicle body  1608 , and a pair of thrust producing means  1618 ,  1620  disposed on the mounting bar  1612  distal to the vehicle body  1608 . In the example shown, thrust producing means  1614 ,  1616  are counter rotating rotors. One thrust producing means  1614  is arranged to rotate clockwise, applying an anti-clockwise torque to mounting bar  1610 , while the other thrust producing means  1616  is arranged to rotate anti-clockwise, producing a clockwise torque to mounting bar  1610 . Similarly, in the example shown, thrust producing means  1618 ,  1620  are counter rotating rotors. One thrust producing means  1618  is arranged to rotate anti-clockwise, applying a clockwise torque to mounting bar  1612 , while the other thrust producing means  1620  is arranged to rotate clockwise, applying an anti-clockwise torque to mounting bar  1612 . 
     Example implementations that provide such counter-rotating rotors or counter-acting thrust producing means that have thrust lines (not shown) that intersect an axis to be controlled, such as, for example, one, or both, of axes  1622 ,  1624  of the mounting bars  1610 ,  1612  realises at least one, or both, of a lower mass moment of inertia about those axes or a reduced actuation resistance due to a lower gyroscopic effect that, in turn, reduces actuator load. Still further, example implementations, having a plurality of mounting bars per arm bearing multiple thrust producing means such as, for example, two mounting bars per arm each with two rotors, experience, as the bars are rotated, a component of differential thrust able to produce a moment about the arm axis that diminishes until, when the thrust producing means axes are parallel to the arm axis, the differential thrust cannot contribute to the moment at all, at which point, example implementations use torque differentials across the thrust producing means to provide a turning moment about the arm axis. However, since a torque differential is typically related to a corresponding thrust differential, an undesirable coupling can result. The coupling can, nevertheless, be at least reduced, or removed, by providing further thrust producing means acting about the arm as depicted in  FIG. 16 , where a net thrust acts along the arm axis  1606  whilst a net moment acts about the arm axis as shown in  FIG. 17 . 
     Referring to  FIG. 17 , there is shown a view  1700  of the example implementation described with reference to  FIG. 16 , in which thrust differentials and torque differentials are decoupled using multiple rotor bearing mounting bars  1610 ,  1612  coupled to the same arm  1604 . The thrust and torque  1702 ,  1704  associated with the thrust producing means  1614 ,  1616  respectively, in conjunction with the torque and thrust  1706 ,  1708  associated with the thrust producing means  1618 ,  1620  respectively, lead to a net moment about the arm axis  1606  that can be controlled independently of a net force generated along the arm axis  1606 , whilst introducing no moment on the arm axis  1606  in any plane in which said arm axis lies. 
     Example implementations that use one or more actuators rather than thrust or torque differentials produced by the thrust producing means to control rotation about an axis can reduce the need for additional thrust producing means that, in turn, since additional thrust producing means would tend to be smaller and less efficient for a given size of vehicle, results in reduced vehicle efficiency. Conversely, example implementations that use thrust or torque differentials produced by thrust producing means to control rotation about an axis remove the need for an actuator at all, or can allow a smaller actuator to be used and can result in an improved system or control response. The selection of an appropriate combination of actuation and the application of thrust or torque differentials produced by thrust producing means is key to vehicle performance. 
     Consequently, example implementations that use actuators to control the rotation of the mounting bar axes can reduce the need for as many smaller, less efficient, thrust producing means. Example implementations can be realised that use two thrust producing means per mounting bar where an actuator is used to rotate that mounting bar about its mounting bar axis. Beneficially, such an arrangement wherein the two thrust producing means lie close to the mounting bar axis provide for a low mass moment of inertia about the mounting bar axis. Furthermore, where the two thrust producing means comprise a pair of counter-rotating rotors, gyroscopic effect about the mounting bar axis is also low. Both these attributes make the mounting bar axis in such an arrangement amenable to actuation. Example implementations that use such an arrangement do not need to additionally actuate the arm axis, since rotation about the arm axis in such an arrangement may be controlled by net thrusts and/or moments produced by the thrust producing means on the mounting bars. Consequently, having the arm axis controlled by a net moment produced by the thrust producing means and having the two mounting bars&#39;  1610 ,  1612  rotation controlled by actuation results in both a highly responsive and efficient vehicle. 
     In such an arrangement it will be appreciated that moments about the arm axis  1606  are generated by the thrust producing means  1614 ,  1616  and  1618 ,  1620  disposed either side of the arm axis  1606 . Beneficially, since the thrust producing means lie on either side of the arm axis  1606 , rotation of the thrust producing means  1614  to  1620  about their respective mounting bar axes is unconstrained by the risk of collision with the arm  1604 , and rotation about a mounting bar axis can be readily effected using an actuator since each thrust producing means axis substantially intersects its respective mounting bar. (Since each thrust producing means axis substantially intersects a respective mounting bar axis, the thrust producing means cannot produce large moments about their respective mounting bar axes; such large moments could be detrimental to actuation, could require a more powerful actuator to overcome such moments, or could require a more complex control system to synchronise moments produced by the actuator with moments produced by the thrust producing means.) 
     A thrust vectoring module comprising a single mounting bar and no actuators can apply a net force and moment to the vehicle body, but the force and moment will be coupled in magnitude such that at least three such modules would be required to control the vehicle in six degrees of freedom. Conversely, a thrust vectoring module comprising multiple mounting bar axes and no actuator can apply a force and moment to the vehicle body that are decoupled in magnitude such that only two such modules are required to control the vehicle in six degrees of freedom. 
     Any or all of the example implementations described herein can carry one or more sensors, one or more payloads, one or more actuators, one or more effectors or the like. 
     Referring to  FIG. 18 , there is shown a view  1800  of a flight controller  1802  of any vehicle according to example implementations. The controller  1802  comprises a thrust producing means controller  1804  for controlling the thrust producing means of example implementations. Controlling the thrust producing means comprises controlling at least one or more of controlling rotor speed, rotor collective pitch, forces or moments associated with the thrust producing means taken jointly and severally in any and all permutations. The controller  1802  comprises thrust vectoring module attitude controller  1806  to control the attitude of the thrust vectoring modules of example implementations. The controller  1802  comprises a mounting bar attitude controller  1808  to control the rotation of the mounting bars according to example implementations. Each of the controllers  1804  to  1808  can output data or signals  1810  to  1814  respectively for controlling the thrust producing means, thrust vectoring modules and mounting bars respectively. Although the flight controller  1802  comprises attitude controllers  1806  and  1808 , one skilled in the art will appreciate that these controllers  1806 ,  1808  may additionally or alternatively act to control rotational accelerations and rates. 
     It will be appreciated that the controllers and any associated circuitry as used herein can comprise any of physical electronic circuitry, software (such as machine-readable and machine-executable instructions), hardware, application specific integrated circuitry, or the like, taken jointly or severally in any and all permutations. 
     Therefore, implementations also provide machine-readable storage storing such machine-executable instructions. The machine-readable storage can comprise transitory or non-transitory machine-readable storage. The machine can comprise one or more processors, or other circuitry, for executing the instructions or implementing the instructions. 
     Accordingly, referring to  FIG. 19 , there is shown a view  1900  of implementations of machine-readable storage  1902 . The machine-readable storage  1902  can be realised using any type of volatile or non-volatile storage such as, for example, memory, a ROM, RAM, EEPROM, or other electrical storage, or magnetic or optical storage or the like. The machine-readable storage  1902  can be transitory or non-transitory. The machine-readable storage  1902  stores machine-executable instructions (MEIs)  1904 . The MEls  1904  comprise instructions that are executable by a processor or other instruction execution, or instruction implementation, circuitry  1906 . The processor or other circuitry  1906  is responsive to executing or implementing the MEls  1904  to perform any and all activities, operations, or methods described and/or claimed in this application such as the operations described with reference to at least one or more of  FIGS. 1 to 18 . 
     The processor or other circuitry  1906  can output one or more than one control signal  1908  for controlling other devices  1910 . Example implementations of such other devices  1910  comprise, for example, at least one or more than one of thrust producing means, thrust vectoring modules, mounting bars or actuators taken jointly and severally in any and all permutations. 
     Suitably, the machine-executable instructions  1904  comprises machine-executable instructions for controlling the vehicle during, for example, flight in the case of an air vehicle, or submersion in the case of a submersible vehicle. The machine-executable instructions comprise instructions  1912  to control the thrust producing means, instructions  1914  to control the thrust vectoring modules and instructions  1916  to control the mounting bars. 
     It will be appreciated that any or all of the thrust vectoring modules described herein can comprise at least one thrust producing means mounted on a respective mounting bar that is rotatably coupled to a respective arm. Any and all example implementations can be realised in which a thrust vectoring module comprises a plurality of thrust producing means mounted on a respective mounting bar that is rotatably coupled to a respective arm. Furthermore, any and all example implementations can be realised in which a thrust vectoring module comprises at least one arm having one or more than one rotatably coupled mounting bar with each mounting bar bearing one or more than one thrust producing means. Therefore, example implementations can be realised in which a thrust vectoring module comprises a plurality of mounting bars each bearing one or more thrust producing means where each bar, or at least one or more than one bar, is rotatably coupled to a respective arm. Still further, example implementations can be realised that comprise a plurality of arms with each arm bearing one or more than one rotatably coupled mounting bar where each mounting bar comprises one or more than one thrust producing means. Example implementations in which a thrust vectoring module comprises a plurality of mounting bars with respective one or more thrust producing modules can be arranged such that selected thrust producing means have counter-rotating rotors. For example, example implementations can be realised in which the thrust producing means of one or more than one mounting bar have counter rotating rotors. Additionally, and alternatively, example implementations can be realised in which the thrust producing means of one or more than one bar have counter rotating rotors compared to the thrust producing means of one or more than one other bar, wherein the bars can be supported by a common arm or respective arms. 
     It will be appreciated that the rotations about the arm axes and bar axes in any or all example implementations can be realised using at least one, two or all, of differential forces, differential moments or respective actuators taken jointly and severally in any and all permutations. Rotations realised using at least one of differential forces or differential moments can be augmented or replaced by rotations using respective actuators. In addition to the foregoing, the thrust and moments, or torque, can be generated by collective or pitch control of the rotors in addition to, or as an alternative to, generating forces and moments using at least one of differential forces, differential moments or actuators taken jointly and severally in any and all permutations. 
     Example implementations generally comprise a control system for a vehicle, a vehicle with such a control system, and methods for controlling a vehicle using such a control system. 
     Example implementations provide a vehicle generally comprising a thrust vectoring module, which, in turn, comprises a plurality of thrust producing means. The thrust vectoring module can be controlled to generate a wide range of forces and moments on the vehicle, substantially independently of the vehicle&#39;s orientation in space. 
     In an example implementation a fluid borne vehicle comprises a thrust vectoring module affixed to the vehicle, wherein the thrust vectoring module comprises a plurality of thrust producing means rotatable about an axis fixed to the vehicle. 
     In a further example implementation, a fluid borne vehicle comprises a thrust vectoring module affixed to the vehicle, wherein the thrust vectoring module comprises a plurality of thrust producing means rotatable about an axis fixed to the vehicle, wherein differing the thrust produced by the thrust producing means causes the plurality of thrust producing means to rotate about the axis fixed to the vehicle, thus vectoring the thrust of the thrust vectoring module. 
     In a still further example implementation, a fluid borne vehicle comprises a plurality of thrust vectoring modules affixed to the vehicle, wherein a thrust vectoring module comprises a plurality of thrust producing means rotatable about an axis fixed to the vehicle, wherein differing the thrust produced by the thrust producing means causes the plurality of thrust producing means to rotate about the axis fixed to the vehicle, thus vectoring the thrust of the thrust vectoring module. 
     In a yet further example implementation, a fluid borne vehicle comprises a thrust vectoring module affixed to the vehicle, wherein the thrust vectoring module comprises a plurality of thrust producing means rotatable about a first axis that is rotatable about a second axis fixed to the vehicle, wherein an actuator causes the plurality of thrust producing means to rotate about the first axis, and differing the thrust produced by the thrust producing means causes the plurality of thrust producing means to rotate about the second axis, thus vectoring the thrust of the thrust vectoring module. 
     Example implementations can be realised according to any of the following clauses: 
     Clause 1. A fluid-borne vehicle comprising a plurality of thrust vectoring modules, wherein each thrust vectoring module comprises a plurality of thrust producing means, wherein a first thrust producing means is rotatable about a first axis and the first axis is rotatable about a second axis, which is not substantially parallel to the first axis; and a second thrust producing means is rotatable about a third axis and the third axis is rotatable about the second axis, which is not substantially parallel to the third axis. 
     Clause 2. A fluid-borne vehicle as in clause 1, wherein the first axis is rotatable about the second axis by individually varying the thrust produced by a plurality of thrust producing means in order to produce a moment that causes the first axis to rotate about the second axis. 
     Clause 3. A fluid-borne vehicle as in clause 1, wherein the first axis is rotatable about the second axis by an actuator. 
     Clause 4. A fluid-borne vehicle comprising a thrust vectoring module, wherein each thrust vectoring module comprises a plurality of thrust producing means, wherein a first plurality of thrust producing means is rotatable about a first axis and the first axis is rotatable about a second axis, which is not substantially parallel to the first axis; and a second plurality of thrust producing means is rotatable about a third axis and the third axis is rotatable about the second axis, which is not substantially parallel to the third axis. 
     Clause 5. A fluid-borne vehicle as in clause 4, wherein the first axis is rotatable about the second axis by individually varying the thrust produced by a plurality of thrust producing means in order to produce a moment that causes the first axis to rotate about the second axis. 
     Clause 6. A fluid-borne vehicle as in clause 4, wherein the first axis is rotatable about the second axis by an actuator. 
     Clause 7. A fluid-borne vehicle as in any of the preceding clauses, wherein the first and third axes are in a fixed relation to each other. 
     Clause 8. A fluid-borne vehicle as in any of the preceding clauses, wherein the vehicle comprises an elongate body. 
     Clause 9. A fluid-borne vehicle as in any of the preceding clauses, wherein the vehicle is adapted to carry a sensor. 
     Clause 10. A fluid-borne vehicle as in any of the preceding clauses, wherein the vehicle is adapted to launch a projectile or fire a beam of directed energy. 
     Clause 11. A fluid-borne vehicle as in any of the preceding clauses, wherein the vehicle comprises a crawling device for attachment to surfaces. 
     Clause 12. A fluid-borne vehicle as in any of the preceding clauses, wherein in a first configuration of the vehicle, the exhaust from a thrust producing means of the first thrust vectoring module substantially impinges on a thrust producing means of the second thrust vectoring module when the vehicle body is in a certain orientation and the first thrust vectoring module is generating a certain net force and a certain net moment on the vehicle; in a second configuration of the vehicle, the exhaust from no thrust producing means of the first thrust vectoring module substantially impinges on any thrust producing means of the second thrust vectoring module when the vehicle body is substantially in the same orientation and the first thrust vectoring module is producing substantially the same net force and net moment on the vehicle; and the vehicle is adapted to avoid the first configuration in preference to the second.