Control mechanism strategies for spin-stabilized projectiles

Fresconi, Frank; Plostins, Peter

doi:10.1243/09544100jaero705

Cited by 31 publications

(22 citation statements)

References 9 publications

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“…Fuzing and warhead are contained in the central portion of the projectile body. The maneuver mechanism is placed at the aft end of the spin-stabilized projectile to maximize control authority [15][16]. This mechanism consists of a rotary motor (shown in red in Figure 1) linked to a deflected wing (light blue in Figure 1).…”

Section: A Projectile Conceptmentioning

confidence: 99%

Guidance and Control of a Man Portable Precision Munition Concept

Fresconi

Rogers

2015

AIAA Atmospheric Flight Mechanics Conference

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Small diameter, gun-launched projectiles pose a challenging platform on which to implement closed-loop guidance and control. This paper presents a novel imager-based guidance and control algorithm for small diameter, spin-stabilized projectiles. The control law is specifically formulated to rely on feedback only from a strap-down detector and roll angle sensors.Following introduction of the projectile nonlinear dynamic model, an integrated guidance and control algorithm is presented in which control commands are computed directly from detector feedback using a gain-scheduled proportional control. Time-varying controller gains are derived through a surrogate modeling approach, and controller performance is further enhanced through use of an observer that filters unwanted angular motion components from detector feedback.Example closed-loop flight simulations demonstrate performance of the proposed control system, and Monte Carlo analysis shows a factor of two accuracy improvement for the closed-loop system over ballistic flight. Results indicate that delivery system improvements are achievable in small, gyroscopically-stabilized projectiles containing low cost guidance elements using the proposed integrated guidance and control approach. mass [kg]This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. AIAA SciTech I moment of inertia matrix [kg-m 2 ] , ⁄ total velocity of projectile with respect to the wind, velocity of center of gravity with respect to inertial frame in body-fixed coordinates [m/s] atmospheric density [kg/m 3 ] dynamic pressure at projectile mass center [N/m 2 ] q M dynamic pressure at wing actuator center of pressure [N/m 2 ] Mach number √ pitch angle-of-attack [rad] √ yaw angle-of-attack [rad] √ √ total angle-of-attack [rad] aerodynamic roll angle [rad] , , aerodynamic forces acting on projectile [N] , , gravity forces acting on projectile [N] , , aerodynamic moments acting on projectile [Nm] , , total, zero-yaw, and yaw-dependent axial force coefficient , , , total, trim, linear and nonlinear normal force coefficient roll damping moment coefficient , , , total, trim, linear and nonlinear pitching moment coefficient pitch damping moment coefficient Magnus force coefficient Magnus moment coefficient , , , Wind actuator aerodynamic coefficients , axial center-of-pressure, radial CP [m] → vector from center-of-gravity to i th moveable Downloaded by NANYANG TECHNICAL UNIVERSITY on October 1, 2015 | http://arc.aiaa.org | aerodynamic surface center-of-pressure [m] , , , Φ, Earth-fixed commanded, Earth-fixed control, body-fixed control, relative, and stowed roll angles [rad] 1 0 0 0 Φ Φ 0 Φ Φ transformation matrix from body-fixed to moveable aerodynamic surface coordinates transformation matrix from body-fixed to Earthfixed coordinates transformation matrix from body-fixed to wing surface coordinates transformation matrix from velocity vector coordinates to Earth-fixed coordinates , , inertial position [m] , , inertial translational veloc...

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Section: A Projectile Conceptmentioning

confidence: 99%

Guidance and Control of a Man Portable Precision Munition Concept

Fresconi

Rogers

2015

AIAA Atmospheric Flight Mechanics Conference

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“…The maneuver mechanism is placed at the aft end of the spin-stabilized projectile to maximize control authority (14,15). The maneuver section includes power conditioning electronics, processor, microelectromechanical inertial sensors, battery, and the actuator.…”

Section: Conceptmentioning

confidence: 99%

Guidance and Control of a Man-Portable Precision Munition Concept

Fresconi¹,

Rogers²

2014

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Approved for public release; distribution is unlimited.ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)June 2014 ARL-TR-6966 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThe hypothesis of this report is that delivery accuracy of small-diameter spin-stabilized projectiles can be improved through novel guidance and control techniques using low-cost components. A gyroscopically stable projectile equipped with a strap-down detector and rotary actuation assembly is introduced. Flight models are formulated to enable nonlinear simulation. The unique guidance challenges posed by characteristics of spin-stabilized flight dynamics such as limit cycles, center-ofgravity swerve, instability, and practical feedback are illustrated. New guidance and control techniques to circumvent these difficulties are proposed. Modeling, parameter estimation, and stability analysis results underpin control design. Representative feedback, control commands, and flight behaviors from nonlinear simulations demonstrate the efficacy of this guidance approach. Monte Carlo analysis shows more than a factor of two in accuracy improvement of the guided over the ballistic flight. These results indicate that delivery system improvements are achievable in small, gyroscopically stable projectiles containing low-cost guidance elements using integrated control formulations. iii SUBJECT TERMS

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“…The nature of the applied force and moment of this mechanism is similar to an impulse where the magnitude cannot be controlled and the paddle force is only active for a portion of the roll cycle. 1,26 The forces acting on the paddle can be modeled as an axial force coefficient C XC and normal force coefficient C NC . The paddle also produces a yawing moment given by the cross product of the control forces given in equation (13) with the position vector from the projectile center of mass to the center of pressure of the paddle.…”

Section: Application To An Example Smart Projectilementioning

confidence: 99%

“…Canards are a very common control mechanism used on all types of projectiles, typically consisting of a pair of canards mounted on the nose of the projectile that, when deflected, produce a normal and axial force on the projectile. 1,2 Other types of mechanisms can be used to create aerodynamic asymmetries which can be used to guide a projectile. Some examples are spoilers mounted at the rear of a fin-stabilized projectile 3 and a spin-stabilized projectile with a nose capable of moving relative to the projectile body.…”

Section: Introductionmentioning

confidence: 99%

Impact point model predictive control of a spin-stabilized projectile with instability protection

Gross

Costello

2013

Proceedings of the Institution of Mechanical Engineers, Part G:

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Most smart projectile control systems generate lateral control forces to guide the round to a target. Experience has shown that under the right combination of body orientation, translational velocity, and angular velocity, relatively low lateral control force inputs can induce instability of the round. To solve this problem, an additional control logic layer is appended to a nominal impact point flight control law to protect it from instability in these infrequent, but consequential situations. To highlight the newly developed control logic, a smart 155 mm spin-stabilized projectile equipped with a rotating paddle control mechanism is considered. For this example configuration, cross range maneuvering occasionally induces instability. Simulation results, using both rigid and multi-body nonlinear flight dynamics models, indicate that the addition of the instability protection layer in the control logic prevents projectile instability while not substantially altering target impact statistics. The nature of this protector design lends itself well to the use of a GPU to perform the calculations, greatly decreasing the computation time needed.

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Control mechanism strategies for spin-stabilized projectiles

Cited by 31 publications

References 9 publications

Guidance and Control of a Man Portable Precision Munition Concept

Guidance and Control of a Man Portable Precision Munition Concept

Guidance and Control of a Man-Portable Precision Munition Concept

Impact point model predictive control of a spin-stabilized projectile with instability protection

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