Showing papers on "Missile published in 1995"

Proportional navigation and weaving targets

Abstract: Sinusoidal or weave maneuvers on the part of the target can make it particularly difficult for a pursuing missile to hit. Normalized design curves are presented so that the guidance system designer can easily assess the influence of weave maneuvers on missile system performance. These curves show how the target weave frequency and amplitude along with the interceptor guidance system tune constant and effective navigation ratio determine the size of the miss distance. Acceleration saturation effects also are considered as a further important influence on system performance. Finally, suggestions are made showing how to improve system performance.

LPV control design for pitch-axis missile autopilots

Abstract: The missile pitch-axis autopilot is designed using linear parameter-varying (LPV) control theory. The controller guarantees quadratic stability and bounded induced L/sub 2/-norm performance for the missile plant. Our approach is motivated by gain-scheduling methodology and provides a well founded and systematic procedure for high performance missile autopilot design.

Guidance of a homing missile via nonlinear geometric control methods

Abstract: This paper examines the guidance problem of an acceleration constrained homing missile when the initial missile heading is far from intercept course. A guidance strategy based on the theory of feedback linearization is presented, and simulation results are given comparing miss distance performance of the feedback linearized guidance law to proportional navigation. It is demonstrated that the feedback linearized guidance law is a viable option under these conditions. aT L*A(r) LgLkfh(x) N'

Supersonic combustion ramjet missile

Abstract: During the period of 1962-1978, the Applied Physics Laboratory of Johns Hopkins University developed the technology for a family of missiles named SCRAM for use as fleet defense weapons. SCRAM is the acronym for supersonic combustion ramjet missile. The development work began with the conceptual design of two missile configurations and calculations of the expected performance for a variety of missions to provide defense for the surface fleet. A novel class of multimodule fixed-geometry hypersonic inlets was designed and wind-tunnel models were built and tested at Mach numbers of 4-10 at angles of attack up to 15 deg. Injector and combustor development was carried out in direct connect test apparatus. Considerable effort was directed to the development and testing of a wide variety of storable, reactive liquid fuels including boranes and aluminum alkyls. Many new testing techniques and diagnostic instruments were developed that are still key elements of scramjet test operations. The program culminated with the testing of the entire engine in free jets at Mach numbers of 57.3 and the design of a family of revised vehicle configurations that could exploit the full capability of the performance observed in the ground test program. This article presents the highlights of the technology program and references recently released documents.

Design and evaluation of robust nonlinear missile autopilots from a performance perspective

Abstract: In this paper a general uncertainty model for a nonlinear missile system is developed, which assumes uncertainties in all aerodynamic force and moment generating terms in the equations of motion. These uncertainties are then bounded and used as a deterministic model in the design of two robust nonlinear missile autopilots. The first approach is an input/output linearized robust controller design, and the second is a recursive robust nonlinear controller design. The general uncertainty model is then used to define limited bandwidth stochastic perturbations for the evaluation of these autopilots. The resulting performance evaluations and comparisons are obtained through computer simulation and by Monte Carlo analysis.

High-Performance, Robust, Bank-to-Turn Missile Autopilot Design

Abstract: Subjects related to a robust multivariable autopilot design are examined in this paper. First, a canonical robust control design formulation is introduced and is illustrated by formulating an integrated autopilot design problem. This formulation addresses the considerations of missile command following, model parameter variations, actuator dynamics, flexible dynamics, and parasitic feedback effects. Then, three robust autopilot designs for the HAVE DASH II missile system are executed. The controllers are solved using the generalized Hamiltonian approach which unifies a class of robust control designs in the same framework in terms of the formulation, data structure, and solution algorithm. The simulation shows that the designs achieve good response against significant kinematic and inertia couplings and aerodynamic parameter variations.

Device for self-defense against missiles

Abstract: The invention relates to a device for self-defense of aircraft against missiles and provides for a combination of a proximity sensor for the enemy missile, an intercepting rocket, and an aimed light beam, with the light beam optionally being used alone as an optical jammer against an optical homing head on the missile, or being used together with the intercepting rocket to steer it optically by either a semi-active or a beam rider steering method.

Reinforcement Learning Applied to a Differential Game

Abstract: An application of reinforcement learning to a linear-quadratic, differential game is presented. The reinforcement learning system uses a recently developed algorithm, the residual-gradient form of advantage updating. The game is a Markov decision process with continuous time, states, and actions, linear dynamics, and a quadratic cost function. The game consists of two players, a missile and a plane; the missile pursues the plane and the plane evades the missile. Although a missile and plane scenario was the chosen test bed, the reinforcement learning approach presented here is equally applicable to biologically based systems, such as a predator pursuing prey. The reinforcement learning algorithm for optimal control is modified for differential games to find the minimax point rather than the maximum. Simulation results are compared to the analytical solution, demonstrating that the simulated reinforcement learning system converges to the optimal answer. The performance of both the residual-gradient and non...

Near-optimal three-dimensional air-to-air missile guidance against maneuvering target

Abstract: Closed-loop guidance of a medium-range air-to-air missile (AAM) against a maneuvering target is synthesized using a three-phase, near-optimal guidance scheme. A large period of the closed-loop guidance is performed using neighboring optimal control techniques about open-loop optimal solutions obtained by solving the associated minimum time to intercept trajectories. The first phase is the boost phase guidance where the normal acceleration limit may be active due to high lofting of the boost-sustain-coast AAM. The guidance in this phase accommodates only errors in the missile's state variables, the target maneuvering being neglected. The boost phase guidance involves guidance in the presence of active control constraints. The second phase is the midcourse guidance where both state perturbations and target maneuvers are considered. Comparisons are made between guidance with gain indexing performed with clock time and with performance index to go. Models of aggressive target and run-away targets were used and the guidance scheme performance is excellent. Three methods of optimal gain evaluation are also discussed. Performance augmentation is obtained by using a center of attainability as a pseudotarget that fairs into the actual target as time to go becomes zero. The final phase is the terminal guidance, which employs proportional navigation and its variants.

Interception of spiraling ballistic missiles

Abstract: During re-entry the rolling velocity of the non-separating tactical ballistic missile caused by configurational asymmetries will normally pass through the missile pitch frequency. This may result in a large amplitude circular yaw and a severe spiraling of the vehicles center of mass. The presence of a static aerodynamic induced rolling moment may cause the roll rate to lock-in at the critical frequency in which case the severity of this spiraling motion is greatly increased. Both the amplitude and frequency of spiraling generally increase as the missile descends in altitude. The frequency of the motion is in the range 0.5 to 1 Hz which is the range of target weave frequencies most critical for fast-response proportional navigation interceptors. These motions can cause significant miss distance in a conventional proportional navigation guidance system. This paper demonstrates the advantages of using a weave guidance law. The paper shows that an alternative approach to improving interceptor performance is by improving the guidance law used to steer the missile. If the target weave frequency can be estimated the paper shows that the compensated weave guidance law substantially improves system performance.

Dual-control scheme for improved missile maneuverability

Abstract: A cooperative dual-control strategy actuates forward and aft control devices simultaneously to significantly improve a missile's maneuverability/dynamic capability. A substantial, and measurable, operational effect of the inventive control strategy is a dramatic improvement in a missile's divert capability. To effect a maneuver in accordance with the inventive strategy, a missile's aft fins are initially deflected to generate a force OPPOSITE that conventionally used (pushing the missile's tail in the direction of the commanded maneuver) while simultaneously actuating forward thrusters to also push the missile's nose in the direction of the commanded maneuver but at a faster rate than the tail section. This causes the missile body to simultaneously rotate and translate in the direction of the commanded maneuver. Once a sufficient amount of aerodynamic force develops due to body rotation, the aft fins are deflected to generate a force that opposes the commanded maneuver to maintain a moment on the missile body and complete the commanded maneuver. An important benefit of cooperative dual-control strategy is that the missile begins to translate in the direction of the commanded maneuver immediately (conventional isolated aft control schemes do not accomplish this) and at a faster rate than is possible with either isolated forward control devices or an intuitive dual-control approach.

Missile flight control using active flexspar actuators

Abstract: A new type of subsonic missile flight control surface using piezoelectric flexspar actuators is presented. The flexspar design uses an aerodynamic shell which is pivoted at the quarter-chord about a graphite main spar. The shell is pitched up and down by a piezoelectric bender element which is rigidly attached to a base mount and allowed to rotate freely at the tip. The element curvature, shell pitch deflection and torsional stiffness are modeled using laminated plate theory. A one-third scale TOW 2B missile model was used as a demonstration platform. A static wing of the missile was replaced with an active flexspar wing. The 1' X 2.7' active flight control surface was powered by a bi-morph bender with 5-mil PZT-5H sheets. Bench and wind tunnel testing showed good correlation between theory and experiment and static pitch deflections in excess of +/- 14 degree(s). A natural frequency of 78.5 rad/s with a break frequency of 157 rad/s was measured. Wind tunnel tests revealed no flutter or divergence tendencies. Maximum changes in lift coefficient were measured at (Delta) CL equals +/- .73 which indicates that terminal and initial missile load factors may be increased by approximately 3.1 and 12.6 g's respectively, leading to a greatly reduced turn radius of only 2,400 ft.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Self-propelled rescue apparatus

Abstract: Rescue apparatus comprising a self-propelled missile mounted on a hand-held launcher and arranged to carry a flotation device in a collapsed condition from the launcher to a distressed target, the launcher and flotation device being connected by a flexible line, so that when the missile is aimed and launched toward the target, the flotation device is carried to the target and then deployed automatically to provide flotation support and establish a "life-line" from the launcher.

Augmentation of High-Altitude Maneuver Performance of a Tail-Controlled Missile Using Lateral Thrust,

Abstract: : Tactical ballistic missiles (TBM's) may experience severe spiral maneuvers as they reenter the earth's atmosphere. It has been estimated that these maneuvers may increase in magnitude from 1 to 10 g's as the vehicle descends in altitude from 100 to 60 kft. The maneuvers also occur within the frequency range 0.5 to 1.0 Hz. This imposes the greatest difficulty on present-day proportional navigation interceptors. To hit these targets the interceptor must possess extremely fast maneuver response characteristics. At the altitudes mentioned this is generally impossible with aerodynamic control. This study investigates the possibility of achieving the desired interceptor time constant with a combination of aerodynamic and lateral-thrust control. The basic concept involves the use of conventional aerodynamic control for most of the terminal engagement with transition to blended control as time-to-go approaches zero. As a modification to existing airframes, the feasibility of the concept depends on the peak level of the thrust required, the location of the thrust device along the missile body, and the necessary total impulse. These factors are addressed in relation to a typical tail-controlled interceptor. A simple blended-autopilot control theory is developed and the improvement in miss distance performance that results from the concept is indicated. Two of the more important findings of the study are that there is an optimum location along the missile body for the point of application of the thrust and that the time-to-go for transition from aerodynamic to blended control should approximate 0.5 sec.

Missile test method for testing the operability of a missile from a launch site

Abstract: A missile is tested by first stimulating the performance of missile built-in tests that are stimulated in service by signals from the launch site, and which tests do not require internal access to the missile. If performance is satisfactory, no further testing is required. If a condition of unsatisfactory missile performance is detected, an access cover is removed, connections are made to internal sources of data, and the built-in tests are repeated in order to determine which internal components caused the unsatisfactory missile performance. The component is repaired. The testing with the access cover removed is repeated, and, if the performance is satisfactory, the access cover is replaced and the testing with the access cover present is repeated.

Improved command to line-of-sight for homing guidance

Abstract: The command to line-of-sight (CLOS) guidance is known to require very high acceleration commands as the distance between a missile and its target becomes closer. Therefore, the CLOS is generally used for midcourse guidance. In order to use the CLOS for homing, an additional feedforward acceleration command (FFC) is necessary. In this correspondence an improved CLOS (ICLOS) technique which includes FFC is proposed. Its performance improvement is demonstrated by applying the technique to a surface-to air missile (SAM). >

Missile system incorporating a targeting aid for man-in-the-loop missile controller

Abstract: A missile is remotely controlled by a person operating with a base controller that displays an image of an aim-point target. Simultaneously, the base controller displays, as an overlay, a prosecutable target locus that represents the outer boundary of the region that may be hit by the missile, in the event that a maximum change in the guidance commands were to be introduced at that moment. The prosecutable target locus depends upon missile performance capability and the location of the missile relative to the aim-point target, which are provided to the base controller.

Missile launching and orientation system

Abstract: This invention concerns a missile launching system, and particularly a missile launching and orientation system. It can be used to modernize missiles with an inclined launch at an angle by transforming them into missiles controlled for circular defense, avoids ejection of the passive mass within the launching area. In order to do this, the launching system comprises launching means, aerodynamic control surfaces with drive and means of orientation including at least one gas generator and nozzles connected to it. Orientation means are located in an annular body rigidly connected to the rear part of the missile body. The outside surface of the annular body is cone-shaped and is covered with a thermal insulating material forming a gas pipe, the profile of which is a continuation of the profile of the nozzle of the missile cruise engine.

Missile simulator apparatus

Abstract: A missile simulator training apparatus (44) for pilot training of an aircraft of the type having at least one missile station, including a pre-launch module (10) for substantially simulating the pre-launch functions of a missile in response to data received from the aircraft. The apparatus also includes an inert factor formed missile body (32), thereby providing the apparatus with static and aerodynamic loads equivalent to that of an actual missile. The apparatus further includes a data link and data capture module (46) for recording all data transactions between the apparatus and the aircraft for post-flight analysis of aircraft and pilot performance.

Fuzzy logic PID controller for missile terminal guidance

Abstract: Demonstrates fuzzy logic terminal guidance for a surface-to-surface missile. A conventional proportional-integral-derivative (PID) guidance scheme is first employed to form the basis for the fuzzy terminal guidance. The PID guidance scheme employs heading and flight path angle errors derived from sensor imagery of target location to compute angular rate commands. The fuzzy logic terminal guidance design procedure involves translating the conventional PID guidance scheme into a fuzzy control structure with the associated fuzzification of input/output variables, encoding of decision-making knowledge into rulebases, and defuzzification. A novel scheme is implemented in which fuzzy rulebases are used to generate and combine PD and PI portions of the guidance commands. Additionally, the fuzzy terminal guidance includes rulebases to control speed and to perform gain scheduling. Performance evaluations demonstrate the feasibility of the approach.

Roll Damping for Projectiles Including Wraparound, Offset, and Arbitrary Number of Fins

Abstract: An algebraic correlation for the roll-damping and roll-producing moments for finned projectiles and missiles has been extended and verified to accept bodies with an arbitrary number of fins—not only cruciform fins, but curved wraparound fins with fin cant, and fins with offset angles. The extended correlation is applicable at subsonic, transonic, and supersonic speeds. A direct method to compute the fin roll-producing moment from the fin normal force is provided to circumvent the existing lengthy and cumbersome semiempirical methods. Seven different missile and projectile configurations with widely varying fin shapes and sizes were tested, and their measured data are tabulated. The present correlation is very simple, and can be used to refine initial configuration selection and thus reduce the number of costly full-flowfield computations. The correlation is limited to missiles with only one set of fins and to small angles of attack.

Apparatus for the remote control of missiles or torpedoes

Abstract: The invention provides an apparatus for the remote control of missiles or torpedoes launched from a launching container, by means of a cable of which a portion is wound onto a supply reel connected with the launching and of which the other portion is wound onto a supply reel in the missile or the torpedo. The supply reel in the launching container is arranged on the forward end of the container, and the supply reel in the missile or torpedo is arranged on the rearward end of the missile or torpedo. The cable section between the two supply reels, before the launching of the missile or torpedo, is fastened along the major portion of its length on the interior wall of the launching container, by means of a gluing arrangement which consists of a material whose combustion temperature is at least by 800° C. lower than the melting temperature of the optical waveguide, or by means of a flexible clamping arrangement whose holding force can be adjusted.

Feedback Linearization Autopilot Design for the Advanced Kinetic Energy Missile Boost Phase

Abstract: This paper describes an application of feedback linearization to the design of an autopilot for the boost phase of the advanced kinetic energy missile, a hypervelocity missile being developed by the U.S. Army Missile Command. The rapid change in missile states during the boost phase, coupled with a requirement for accurate guidance, provide a challenge for the autopilot designer. Application of the feedback linearization methodology permitted an autopilot design to be successfully accomplished without the necessity for generating numerous airframe transfer functions and frozen-point stability plots. The resulting autopilot is easily updated to accommodate changes in the missile design.

Smart canister systems

Abstract: The smart canister systems disclosed herein enables missile population to increase while minimizing the need for additional interface hardware. Particularly, multiplexing and demultiplexing functions and conversion flexibility enable the system to be adaptable to different types of missile characteristics and hardware. A redundant, bi-directional bus architecture with a distributed and dynamically reconfigurable control as well as enhanced built-in-test, fault monitoring and display capability enable the smart canister systems to provide a faster response time and higher launcher availability in a multifarious missile environment.

Simulator for smart munitions testing

Abstract: A missile or other smart munitions simulator uses an analog function simuor to simulate the detector signal of the missile's optical tracking components. The analog function simulator stores convoluted scene data for respective ranges between the missile and the `target` it is tracking. The scene data are stored in respective data matrices, and may correspond to the target itself or to the background. Depending on the value of variables produced during the missile tracking simulation, the analog function simulator accesses elements in the data matrices and interpolates between them, thereby producing an analog signal which simulates the detector signal of the missile's optical tracking components.

Steering loop for missiles

Abstract: In a steering loop for missiles which are guided to a target by means of a seeker head, the seeker head having a limited field of view, the seeker head determines the line of sight to the target by look angles with respect to missile-fixed pitch and yaw axes. A signal processing computer receives the seeker head signals and generates signals which determine the motion of the missile. These signals are applied to a steering system and guide the missile to the target. In order to avoid loss of the target due to limitations of the field of view of the seeker head, the signal processing computer influences the signals determining the motion of the missile such as to ensure a motion of the missile which holds the line of sight always within the field of view.

Missile with deployable control fins

Abstract: A missile (20) includes a missile body (22) and a structure for controlling the flight path of the missile body. The control structure includes at least one control fin (28) and an actuator shaft (38) that supports the control fin (28) for rotational missile control movement about a control axis (30) perpendicular the axis (23) of the missile body (22). A deployment shaft (42) extending from the control fin (28) is rotatable in a deployment shaft bore (46) in the actuator shaft (38), and permits the control fin (28) to rotate from a folded position (56) parallel and adjacent to the missile body (22) to a extended position (58) parallel to the control axis (30)