The present invention relates generally to a system and method for bang-bang control for a guided projectile and, more particularly to a system and method for generating equally spaced resultant force vectors using a bang-bang control actuation system with a plurality of control surfaces mounted tangentially around a surface of the projectile.
Laser-guided projectiles generally use a laser illuminator to mark (e.g., illuminate, “paint”, etc.) a target. The reflected laser light from the target is then detected by the seeker head of the weapon, which sends signals to the weapon's control fins to guide the weapon toward the designated target. Global positioning system (GPS) guided projectiles generally rely on GPS or other location based satellites to guide the GPS-guided projectile to the designated target. It is common for laser-guided projectiles and GPS-guided projectiles to include advanced control and actuation systems to direct the laser-guided projectile to the desired target. Such advanced control and actuation systems substantially increase the complexity of such devices, as well as the costs associated with such devices.
Several challenges exist with implementing a small form factor projectile having a limited engagement range. Such challenges include small form factor components and minimizing costs. It is difficult to utilize such advanced control and actuation systems in a small form factor in a low cost projectile. A 3-axis proportional control actuation system is bulky, as it requires 3 motors, gear trains, and canard storage, for example. Such a system is also expensive as it requires micro machined parts, close tolerances, and a high part count, which may be considered overkill for a near-ballistic flight.
Aspects of the present invention overcome the problems identified above by placing control surfaces (e.g., canards) on a plane that is tangent to the round projectile, such that the lift force generated by the canards is generated through a centerline axis of the projectile. This eliminates the need for an opposing fin to counter roll moment. Sizing the control surfaces to form an equilateral triangle gives each surface equal span, and enables the force generated by two panels to be equal and opposite to that of the opposing panel. The end effect is that each panel only has two active states (neutral (0 deflection) and positive deflection), (neutral (0 deflection) and negative deflection) or (positive deflection and negative deflection. Thus, a solenoid and a return spring (or other return mechanism) may be used to control deflection of the control surfaces. Additionally, the control surfaces may fold along the surface of the projectile, which frees up internal volume and minimizes the length of the control section.
One aspect of the invention relates to a guided projectile including: a body having a circular cross-section in at least a portion of the body; a plurality of actuators housed at least partially within the body; a plurality of control surfaces, wherein each control surface is secured to one of the plurality of actuators and the plurality of control surfaces are tangentially mounted about the cross-section of the body and each of the actuators are configured to impart a positive deflection on one of the control surfaces; a receiver housed within the head portion to for guiding the guided projectile, wherein the receiver outputs information related to a relative position between the guided projected and an associated target; and a processor coupled to the seeker and the plurality of actuators, wherein the processor processes the information output from the seeker to provide bang-bang control of the plurality of control surfaces to guide the guided projectile to the associated target.
Another aspect of the invention relates to a guided projectile including: a cylindrical body having a first axis and a second axis, wherein the first axis is perpendicular to the second axis; a plurality of control surfaces having a length and a width, wherein the each of the plurality of control surfaces are tangentially secured across a surface of the cylindrical body such the length of each of the plurality of control surfaces is substantially perpendicular to the first major axis and the width of each of the plurality of control surfaces is substantially perpendicular to the second major axis in a neutral position; a receiver housed within a portion of the cylindrical body, wherein the receiver guides the guided projectile to an associated target and the receiver outputs information related to a relative position between the guided projectile and the associated target; and a processor operatively coupled to the receiver and the plurality of control surfaces wherein the processor processes the information output from the receiver to provide bang-bang control of the plurality of control surfaces to guide the guided projectile to the associated target.
Another aspect of the invention relates to a method for controlling a guided projectile having a plurality of control surfaces mounted tangentially across a surface of a body the guided projectile and normal to a major axis of the guided projectile, the method including: receiving signals for guiding the guided projectile to an associated target; outputting information related to a relative position between the guided projectile and the associated target; processing the information to provide bang-bang control of the plurality of control surfaces through a plurality of actuators, wherein each of the plurality of control surfaces is operably coupled to one of the plurality of actuators to direct the guided projectile to the associated target; and deflecting at least one of the control surfaces to direct the guided projectile to the associated target.
One aspect of the invention relates to a guided projectile including: a body having a circular cross-section in at least a portion of the body; a plurality of actuators housed at least partially within the body; a plurality of control surfaces, wherein each control surface is secured to one of the plurality of actuators and the plurality of control surfaces are tangentially mounted about the cross-section of the body and each of the actuators are configured to impart a positive deflection on one of the control surfaces; a seeker housed within the head portion to detect electromagnetic radiation for guiding the guided projectile, wherein the seeker outputs information related to distance and/or direction of the detected electromagnetic radiation; and a processor coupled to the seeker and the plurality of actuators, wherein the processor processes the information output from the seeker to provide bang-bang control of the plurality of control surfaces to guide the guided projectile to an associated target.
Another aspect of the invention relates to a guided projectile including: a cylindrical body having a first axis and a second axis, wherein the first axis is perpendicular to the second axis; a plurality of control surfaces having a length and a width, wherein the each of the plurality of control surfaces are tangentially secured across a surface of the cylindrical body such the length of each of the plurality of control surfaces is substantially perpendicular to the first major axis and the width of each of the plurality of control surfaces is substantially perpendicular to the second major axis in a neutral position; a seeker housed within a portion of the cylindrical body, wherein the seeker is configured to detect electromagnetic radiation for guiding the guided projectile to an associated target and the seeker outputs information related to the detected electromagnetic radiation; and a processor operatively coupled to the seeker and the plurality of control surfaces wherein the processor processes the information output from the seeker to provide bang-bang control of the plurality of control surfaces to guide the guided projectile to the associated target.
Another aspect of the invention relates to a method for controlling a guided projectile having a plurality of control surfaces mounted tangentially across a surface of a body the guided projectile and normal to a major axis of the guided projectile, the method including: detecting electromagnetic radiation from a laser source at a seeker; outputting information related to distance and/or direction of the detected electromagnetic radiation; processing the information to provide bang-bang control of the plurality of control surfaces through a plurality of actuators, wherein each of the plurality of control surfaces is operably coupled to one of the plurality of actuators to direct the guided projectile to an associated target; and deflecting at least one of the control surfaces to direct the guided projectile to the associated target.
The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail illustrative embodiments of the invention, such being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Likewise, elements and features depicted in one drawing may be combined with elements and features depicted in additional drawings. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Portions of this disclosure identify GPS as an example of an applicable positioning/navigation technology. However, this description is not intended to limit the invention to GPS receivers. Other positioning technologies such as Russian GLONASS, China COMPASS, Europe Galileo, and India IRNSS are also deemed to be within the scope of the present invention.
Referring now to
The control surfaces 30 may be any desired size and shape. In general, the control surfaces 30 are substantially planar and have a length (L), a width (W) and a thickness (T). The width (W) should be sufficient to provide adequate deflection of the guided projectile 18 to guide the projectile when deployed. The thickness (T) should be sufficient to ensure that the control surface may be adequately attached to an actuator, discussed below, as well as ensuring that the control surfaces do not deform when deployed at high speeds. Preferably, the length (L) of the control surfaces 30 is sufficient to form a desired shape. For example, as illustrated in
As shown in
A similar benefit may result with the control surfaces 30A-30D configured in the shape of a square, as illustrated in
Referring back to
As illustrated in
Referring to
Referring to
Referring to
For positive deflection, the control surface 30 is an extended position. The extended position occurs when a portion of the control surface 30 is deflected such that the planar surface of the control surface 30 is not parallel with the primary axis (A) of the guided projectile 18 and a forward portion of the control surface 30 aligned closer to the body 32 than an aft portion of the control surface 30. For example, the width (W) dimension of the control surface is changed from a neutral position (parallel with the first axis (A) of the body) to a non-parallel or deflected position. This occurs when the aft portion of the control surface 30 is positively deflected outward from the body 32 and the forward portion of the control surface 30 is deflected toward the body 32.
For negative deflection, the control surface 30 is an inverted position, as compared to the extended position. For example, in the inverted position, a portion of the control surface 30 is deflected such that the planar surface of the control surface 30 is not parallel with the primary axis (A) of the guided projectile 18 and an aft portion of the control surface 30 aligned closer to the body 32 than a forward portion of the control surface 30.
Generally, the control surface 30 will be deflected a prescribed deflection angle θ. For example, the control surface 30 will be deflected a prescribed deflection angle θ. The deflection angle θ may vary depending on a variety of factors including, for example, size of the guided projectile, type of actuator used, type of control system, ballistic range, etc. A suitable deflection angle may be in the range of 3-20 degrees, for example.
While neutral, positive and negative deflection of the control panels are contemplated within the scope of this invention, an actuator 40 utilizing bang-bang control is operable to place the control panel in only two positions. For example, the actuator may be configured to place the control panel 30 in a positive deflection position and neutral position, in a negative deflection position and neutral position; or in a positive deflection position and a negative deflection position.
As discussed above, the guided projectile 18 includes a plurality of control surfaces 30 that are secured around the periphery of the body 32 in a manner to form an equilateral triangle. There are substantial advantages to the symmetry of an equilateral triangle. For example, referring to
Likewise, deflection of two of the plurality of control surfaces (e.g., 30A and 30B) results in a deflection force vector substantially normal to a third control surface (30C), as illustrated in
The guided projectile 18 also includes a seeker 50 or a positioning receiver 50 that is operatively coupled to the control surfaces 30 through the actuators 40, as illustrated in
The seeker 50 operates by remaining pointed or otherwise acquiring a desired target or other destination point. Alternatively, the seeker 50 may acquire a point other than an intended destination, but which aids in guidance of the projectile 18 to its intended destination. The seeker 50 may be mounted on a gimbal (not shown) to allow the seeker 50 to move as relative orientation between the guided projectile 18 and the target 16 or destination changes.
The seeker 50 may be any of a variety of known terminal seekers. Two broad categories of terminal seekers are imaging infrared (IIR) seekers and millimeter wave radio frequency (MMW) seekers. In addition to the broad categories of seekers mentioned above, it will be appreciated that any of a wide variety of seekers may be utilized with the control surface configuration described above.
As described above, in the case where the guided projectile 18 includes a positioning receiver for guiding the projectile, the positioning receiver receives positioning signals from the positioning satellites 11 and the positioning receiver outputs appropriate control signals to the actuators 40A-40C to adjust the control surfaces 30A-30C in order to put the guided projectile 18 on a course for reaching its desired destination.
It will be appreciated that the forward body 12 may include other types of components other than those mentioned above. For example, the forward body 12 may include a payload 54, such as a suitable projectile. In addition, the forward body 12 may include communication devices for actively or passively communicating with remote tracking and/or guidance devices, for example.
As discussed with respect to
Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the following claims.
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