Abstract: A controller for an electro-mechanical actuation system (e.g., missile fin actuator) includes a Kalman estimator circuit generating an estimate of operating state including position and velocity of motor, position and velocity of a position-controlled element (PCE), and motor current. The estimate is generated based on a dynamic model explicitly including the effect of structural stiffness and damping in the coupling between the motor and PCE, for example by treating it as a mechanical oscillator having spring and damping constants. The Kalman estimator operates on a motor drive control signal and a measured position signal which may be from a Hall sensor sensing motor position. A linear quadratic regulator circuit applies a state feedback gain matrix to a state vector to generate a control effort signal. The state feedback gain matrix minimizes a quadratic cost function representing variance of the control effort signal and/or the measured position signal.

Abstract: A multi-stage fin deployment assembly includes a rotary actuator configured to release a first spring-loaded stage that, when deployed, releases a second spring-loaded stage to deploy a set of deployable member or fins. By chaining these spring-loaded stages together, a relatively small input force, as provided by the rotary actuator, causes the second spring-loaded stage to generate a relatively large output force on the fins. This multistage force magnification makes it possible for the deployment assembly to utilize smaller actuators that require less power and take up less space, compared to conventional locking mechanisms.

Abstract: A multi-stage fin deployment assembly includes a rotary actuator configured to release a first spring-loaded stage that, when deployed, releases a second spring-loaded stage to deploy a set of deployable member or fins. By chaining these spring-loaded stages together, a relatively small input force, as provided by the rotary actuator, causes the second spring-loaded stage to generate a relatively large output force on the fins. This multistage force magnification makes it possible for the deployment assembly to utilize smaller actuators that require less power and take up less space, compared to conventional locking mechanisms.

Abstract: A servovalve includes a single motor which actuates separate valve members of separate servovalve assemblies. Each of the valve members controls the flow of hydraulic fluid from separate hydraulic fluid sources. In order to provide each valve member with the ability to operate in the event that the other valve member becomes inoperable, such as caused by jamming of the valve member, each servovalve assembly includes a compression assembly that provides each servovalve assembly with a jam-override capability.

Abstract: A direct drive servovalve (10) includes redundant drive motors (14) coupled to a common valve drive shaft (22,24) by a connection device (26). The connection device (26) is configured to allow operation of the servovalve (10) in the case where one or more of the drive motors (14) becomes inoperable, such as caused by jamming or binding of a rotor associated with the drive motor. By use of the connection device (26), in the event that one of the drive motors (14) was to become jammed, the remaining operable motors (14) can continue to stroke or cause translation of a valve member (18) of the direct drive servovalve (10) to allow its continued operation.

Abstract: A shift lock assembly includes a drive member carried by a drive shaft and configured to rotatably couple to a drive motor and a shift mechanism disposed between the drive member and a ground plate, the shift mechanism configured to move between a first position and a second position relative to the drive member and the ground plate. When disposed in the first position, the shift mechanism is configured to couple the drive shaft to the ground plate and decouple the drive shaft from the drive member to allow rotation of the drive member relative to the drive shaft. When disposed in the second position, the shift mechanism is configured to couple the drive shaft to the drive member and decouple the drive shaft from the ground plate to allow rotation of the drive shaft in response to rotation of the drive member.

Abstract: A floating piston actuator for use with multiple hydraulic systems includes a housing and a piston assembly. The piston assembly includes an elongate shaft or ram, at least one secured piston coupled to the ram, and a set of moveable pistons moveably disposed within the housing chamber on the ram such that the set of moveable pistons are translatable relative to a longitudinal axis of the ram. The set of moveable pistons form at least three hydraulically separate actuator cylinders where each of the three hydraulically separate actuator cylinders are disposed in fluid communication with a corresponding pressurized fluid source. The floating piston actuator allows hydraulic redundancy while maintaining a similar length compared to existing multi-system actuators. The floating pistons can be arranged in multiple configurations to allow operation with a hydraulic system failure without force fight or binding and with a higher output force than conventional multi-system actuators.

Abstract: One embodiment is directed to a locking mechanism. The locking mechanism has a housing and a rotary actuator carried by the housing. The rotary actuator includes a shaft and armature disposed around at least a portion of the shaft. The armature is configured to rotate the shaft about a longitudinal axis of the shaft. The locking mechanism also has a cam carried by the shaft and a set of locking balls disposed between the cam and the housing. The locking mechanism has a locking assembly carried by the housing, the locking assembly being axially positionable between a locked position relative to the housing and a released position relative to the housing.

Abstract: A servovalve torque motor includes first and second pole pieces and an armature. Each of the first and second pole pieces includes an armature face that opposes the armature. The area of the armature face of the second pole piece is smaller than the area of the armature face of the first pole piece. The unequal areas of the first and second armature faces create a bias in the servovalve torque motor while allowing the first and second pole pieces to be disposed at equal distances from the armature to define substantially equal air gaps. The inclusion of substantially equal air gaps between the pole pieces and the armature reduces the maximum flux in the armature for the same bias and torque output, compared to conventional servovalve torque motors. The reduction in maximum armature flux decreases armature saturation and improves linearity during operation.

Abstract: A controller for an electro-mechanical actuation system such as a missile fin actuator includes a Kalman estimator circuit which generates an estimate of operating state including position and velocity of motor, position and velocity of a position-controlled element (PCE), and motor current. The estimate is generated based on a dynamic model explicitly including the effect of structural stiffness and damping in the coupling between the motor and the PCE, for example by treating it as a mechanical oscillator having spring and damping constants. The Kalman estimator operates on a motor drive control signal and a measured position signal which may be from a Hall sensor sensing motor position. A linear quadratic regulator circuit generates a control effort signal by applying a state feedback gain matrix to a state vector. The state feedback gain matrix minimizes a quadratic cost function representing variance of the control effort signal and/or the measured position signal.

Abstract: In a normal operating mode, a motor controller provides motor drive current to windings of a motor based on sensor signals to drive the windings in a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition in a given commutation state, then in a first driving step, the windings are momentarily driven according to an advanced commutation state, and during the first driving step, a reverse transition of the sensor signals to a state corresponding to a preceding commutation state is detected.

Abstract: The actuator system has a external rotor motor having: (i) an internal armature configured as a stator having a set of coils wrapped around a set of arms, and (ii) an external permanent magnet rotor having a set of poles configured to rotate less than 90 degrees around the stator. The actuator system has a drive shaft configured to be rotated by the external rotor motor. The actuator system has a drive train connecting the external permanent magnet rotor to the drive shaft, and configured to provide gear ratio to the drive shaft.

Abstract: A device has built-in inductive load testing capabilities. The device includes a device housing, an inductive load disposed within the device housing; and test circuitry disposed within the device housing. The test circuitry is constructed and arranged to effectuate application of a modulated test signal to the inductive load, and obtain a result signal in response to the application of the modulated test signal to the inductive load. The test circuitry is further constructed and arranged to generate an output signal indicating that the inductive load is in one of (i) a shorted inductive load state, (ii) a normal inductive load state, and (iii) an abnormally high inductive load state, based on the result signal. Such test circuitry is well-suited for testing a variety of devices having inductors/coils which are susceptible to defects (e.g., a solenoid, a motor winding, various actuator components, etc.).

Abstract: A position sensing assembly includes a bearing element and a helically shaped rotational member used to drive a portion of a sensor assembly, such as a Digital Rotary Magnetic Encoder. Interaction between the bearing element and a helically shaped rotational member minimizes the presence of backlash in the position sensing assembly. Accordingly, as an actuator assembly drives both a control element, such as a flight control surface, and the position sensing assembly, the sensor assembly generates an output signal that accurately reflects the position of the control element.

Abstract: An electric motor has a stator, and a rotor disposed within the stator. The stator has a set of stator laminations and a set of windings held in position by the set of stator laminations. The rotor is arranged to rotate about an axis. The set of stator laminations is arranged into a stack. Each stator lamination includes an outer section, and a set of teeth coupled to the outer section. Each tooth of the set of teeth extends from that outer section toward the axis. Each tooth has (i) a first end which is proximate to the outer section and distal to the axis, and (ii) a second end which is proximate to the axis and distal to the outer section. A width of the first end of each tooth is substantially greater than a width of the second end of each tooth.

Abstract: A hydraulic actuator is configured to provide redundant boost control to an aircraft within approximately the same space required by a single hydraulic cylinder. The hydraulic actuator includes a housing and a piston assembly disposed within the housing. The piston assembly includes a ram, a first piston secured to the ram, and second and third pistons disposed on the ram such that the second and third pistons are translatable relative to the longitudinal axis of the ram. The pistons form two hydraulically separate actuator cylinders within the space required by a single cylinder which results in a reduction in the weight and size of the hydraulic actuator.

Abstract: A direct drive servovalve device includes (i) a servovalve motor having a stator and a rotor assembly configured to rotate relative to the stator, (ii) a valve member coupled to the rotor assembly, and (iii) a sensor assembly. The sensor assembly includes an interface configured to couple to a controller that controls the servovalve motor, a set of programmable Hall sensors coupled to the interface, and a support. The support (e.g., a ring-shaped collar or sleeve) supports the set of Hall sensors at an installation location which is (i) adjacent to the rotor assembly and (ii) fixed relative to the stator. The set of programmable Hall sensors is configured to provide a set of position signals to the controller through the interface. The set of position signals identifies a rotational position of the rotor assembly relative to the stator.

Abstract: A slot cover actuation assembly controls access through a slot on a projectile. The slot cover actuation assembly includes a slot cover, a fastener (e.g., a screw), and an actuator (e.g., a squib device). The fastener is arranged to position the slot cover at an installation position on the projectile. The slot cover covers the slot on the projectile when the slot cover resides at the installation position. The actuator is arranged to release the slot cover from the installation position on the projectile. The slot cover uncovers the slot on the projectile when the actuator releases the slot cover from the installation position on the projectile, thus allowing a control surface member (e.g., a fin) to deploy.

Abstract: A technique can recover from motor stalls caused by misalignment of motor position sensors such as Hall-effect sensors. In a normal operating mode, a motor controller provides motor drive current to the motor windings based on the sensor signals according to a normal commutation sequence, and monitors for occurrence of a motor stall condition. Upon detecting the motor stall condition, the motor controller first momentarily drives the windings according to one of an advanced commutation state and a delayed commutation state each adjacent to the given commutation state in the normal commutation sequence, and determines whether the motor stall condition persists. If the stall condition persists, then the motor controller next momentarily drives the windings according to the other of the advanced commutation state and the delayed commutation state.

Abstract: A guidable projectile has a central shaft, a projectile body, and a surface control assembly. The projectile body is arranged to rotate around at least a portion of the central shaft during flight of the guidable projectile to provide stabilization. The surface control assembly is supported by the central shaft. The surface control assembly includes a movable member arranged to control a trajectory of the guidable projectile during flight of the guidable projectile, and an electromagnetic actuator interconnected between the central shaft and the movable member. The electromagnetic actuator is arranged to control movement of the movable member relative to the central shaft.