摘要:
A bipolar metai-gas battery cell stack (1) eliminates the heavy bipolar plates (11) of the prior art by means of locating the series electrical connections (25, 27) between oppositely polarized electrodes (5, 7) of adjacent cells (3) external to the cells (3) in a dielectric frame (21, 23). As a result, the reliability of said electrical connections (25, 27) is improved, weight is saved, and reactant gas screens (15) and electrolyte reservoirs (13) can beneficially be made of compressible lightweight materials. Electrolyte is beneficially confined within each cell (3), and secondary (overcharge) gasses are beneficially confined within each cell (3) in a region (17) proximate the positive electrode (7). A hydrophobic barrier (29) and the frame segments (21, 23) prevent intercell migration of electrolyte and secondary gasses.
摘要:
A digital system for controlling the attitude of a spacecraft (14), e.g., a satellite, with respect to three orthogonal axes. The system can control satellites (14) in parking orbit, transfer orbit, or final operational orbit, whether or not the satellite (14) employs one or more momentum wheels. A processor (2) converts weighted data from spacecraft sensors (12), representing angular orientation and angular velocities about each of the three axes, into thruster pulsetrain signatures to command the firing of each of six thrusters positioned about spacecraft (14). A positive and a negative thruster being positioned to impart both directions of angular momentum about each of the three axes. Each thruster pulsetrain signature is created once every processed error cycle period T1, and contains a varying number of pulses of varying widths. A negative feedback PWPF loop (2, 16, 20, 22, 24) is actuated for each of the three axes, preferably several times each Tl inorder to achieve better thrust on/off resolution. The PWPF loops are preferably implemented by digital means. Serial-out shift registers (44, 46) load the thruster pulsetrain signatures into means (48, 50, 52, 54) for firing the thrusters, preferably after splitting the signature pulses into clone pulses in order to minimize the impact of errors due to asynchronization between the clock which loads the registers (44, 46) and the clock which shifts these registers. Data extenders (40, 42) eliminate possible gaps caused by asynchronization, and thus prevent unwanted on/off thruster switching.
摘要:
Disclosed is a method and apparatus for estimating yaw error and roll and yaw disturbance torques from measured roll error and yaw momentum on a continuous on-orbit basis in an orbiting satellite. The information thus obtained can be used to correct continuously for the yaw error by means of, for example, activating a magnetic torquer. Two control loops are described, a fast loop 69 to damp nutations by changing momentum wheel speed, and a slow loop 1 of the Luenberger observer variety. The latter is a yaw error correction loop which also serves to unload yaw momentum. The satellite in which the invention was first incorporated is of the type having three momentum wheels, all situated in the plane orthogonal to the roll axis. h normal operation, two wheels, each having major momentum component along the pitch axis and minor momentum component along the yaw axis, are operable. A third backup wheel aligned along the yaw axis becomes operable only in the eventuality that one of the primary wheels suffers a breakdown during the life of the satellite. The slow speed yaw loop 1 is used to adjust a magnetic coil torquer. It can be implemented in a number of forms including a hard-wired analog form or a digital computer with certain constant scaling factors programmed into the memory of the computer.
摘要:
An externally powered twin-barrel machine gun includes a shuttle (42) having two firing chambers (64), 66). The shuttle linearly moves between two positions so that the firing chambers are alternately fed a round of ammunition and discharged. A feed system (21) has a pair of augers (23, 24) each with a helical groove (26) therein which receives a round of ammunition which obtains a dwell position on a zero pitched section (28) of the grooves. A ramming system (91) rams a round of ammunition to the firing chamber aligned therewith and simultaneously ejects anyspent cartridge through a forward aperture (62) in the housing (16). The spent cartridge is frictionally engaged by an axially aligned acceleration belt (76) which quickly withdraws the spent cartridge from the firing chamber and accelerates it onto a deflection cam (88).
摘要:
A twin-barrel machine gun has two stationary firing chambers (16,18), a conveyor (26), and a feed system (20) mounted within a housing. The feed system 20 transfers ammunition (22) from the conveyor 26 to the firing chambers 116,18). The feed system (22) includes a sprocket (48) pivotably mounted about its central longitudinal axis. The sprocket (48) has two receptacle slots (50,52) and two discharge slots (62,64) circumferentially spaced thereabout. The sprocket (48) is rotatable between a first and second position. The receptacle slots (50,52) each have a first position aligned with the conveyor to receive a round of ammunition and a second position aligned with a respective firing chamber. One receptacle slot is in its first position when the other is in its second position. The discharge slots also have a first position aligned with a firing chamber and a second position aligned with an outlet in the housing. One discharge slot is in its first position when the other is in its second position. An ejector cam (84) is also rotatably mounted about an axis aligned with the axis of rotation of the sprocket (48). The ejector cam is fitted within a central hollow of the sprocket. A drive gear (78,80,126,128,116,118) connected to the sprocket oscillates the sprocket between its first and second positions and a second drive gear (100,102,90,112,114,116,118) oscillates the ejector cam (84) so that it laterally passes through the first and second discharge slots when in their respective second positions. The ejector cam ejects any cartridges from the discharge slot as it passes therethrough.
摘要:
A DC-DC-Converter of the switching type is disclosed with energy storage on the primary side (6) of the isolation transformer (5). Four transistors (1,2,3,4) or other switching devices are switched sequentially to convert the unregulated input direct current to alternating current. If no rectifiers are used, the output is a substantially squarewave alternating current and hence the device can be used as a DC-AC converter. Multiple outputs (30,40,60) can be used; when the load through them is varied, the output voltage on the other outputs does not appreciably change. The device has a high efficiency (over 85 percent), is current limited, and has no minimum or maximum output voltage limitations. An inductor (21) is employed on the primary side (6) of the transformer (5) for temporary storage during the switching of the transistors (1,2,3,4). The output voltage is regulated by means of pulse width modulation.