and conversion relationship between the steering speed and the speed of the
control surface also depend on it. Therefore, it is an extremely important
parameter of the manipulating mechanism. Only by careful design can the
optimal transmission ratio be obtained.
3. Frequency specification for manipulating mechanism. Manipulating mechanism has dual functions of motion conversion and power transfer. Besides
strength and stiffness specifications, its design should mainly be carried out
according to frequency specifications to meet the dynamic characteristics of
the control surface manipulating mechanism, ensure the frequency bandwidth of the rudder system, prevent the resonance damage of the rudder
control structure, and avoid the aeroelastic problems that may arise in rudder
control, such as the rudder control torsional stiffness is insufficient, which
causes static divergence under counter-manipulating conditions; the coupling of the rudder control torsional bending frequency causes dynamic
flutter under the condition of aerodynamic and energy interconnection.
4. Installation adjustment and clearance of feedback mechanism. Feedback
mechanism is only used for decentralized steering gear. Gear mechanism or
connecting rod mechanism is often used to transfer the control surface
deflection to the steering gear feedback potentiometer with a certain magnification factor, so that the steering system loop is closed. The feedback
mechanism is required to be installed with correct polarity, sufficient
straightness, and symmetry to facilitate precise adjustment (e.g., stepless
adjustment of center distance of gear pair, rod length of connecting rod
mechanism, potentiometer shaft, etc.), inspection, and reliable locking. In
connection with mechanism and installation of potentiometer, the overall
dynamic stiffness and anti-vibration strength of the combination should be
paid special attention. Various technical measures (such as doubleleaf gear
with ring torsion spring, gear with hairspring, and compensating spherical
hinge.) are adopted to eliminate the clearance of the mechanism and ensure
the stability of the rudder system.
5. Setting and type of locking mechanism. Locking mechanism is used to
reliably lock the control surface which is not working for a certain time,
such as the storage and transportation of missile until launching, or before
starting control, or before the separation of the first and second stages of
two-stage missile, and to reliably unlock it when needed. Generally, when
the precision of the electric lock on the return-to-zero line of the rudder
system is limited by the zero error of the rudder system and the moving gap
or the working state of the energy source, the special control surface locking
mechanism must be adopted. The locking mechanism of the control surface
of the second-stage missile must ensure that it is still locked reliably under
the maximum hinge moment in the first-stage flight. When separating, the
lock must be reliably unlocked under the corresponding hinge moment. If
the locking moment is insufficient, the control surface will be unlocked in
advance, which will eventually lead to the air disintegration of the missile.
9.1 Electro-Hydraulic Servo Control Technology of Aircraft Gas Turbine Pump
87
control surface also depend on it. Therefore, it is an extremely important
parameter of the manipulating mechanism. Only by careful design can the
optimal transmission ratio be obtained.
3. Frequency specification for manipulating mechanism. Manipulating mechanism has dual functions of motion conversion and power transfer. Besides
strength and stiffness specifications, its design should mainly be carried out
according to frequency specifications to meet the dynamic characteristics of
the control surface manipulating mechanism, ensure the frequency bandwidth of the rudder system, prevent the resonance damage of the rudder
control structure, and avoid the aeroelastic problems that may arise in rudder
control, such as the rudder control torsional stiffness is insufficient, which
causes static divergence under counter-manipulating conditions; the coupling of the rudder control torsional bending frequency causes dynamic
flutter under the condition of aerodynamic and energy interconnection.
4. Installation adjustment and clearance of feedback mechanism. Feedback
mechanism is only used for decentralized steering gear. Gear mechanism or
connecting rod mechanism is often used to transfer the control surface
deflection to the steering gear feedback potentiometer with a certain magnification factor, so that the steering system loop is closed. The feedback
mechanism is required to be installed with correct polarity, sufficient
straightness, and symmetry to facilitate precise adjustment (e.g., stepless
adjustment of center distance of gear pair, rod length of connecting rod
mechanism, potentiometer shaft, etc.), inspection, and reliable locking. In
connection with mechanism and installation of potentiometer, the overall
dynamic stiffness and anti-vibration strength of the combination should be
paid special attention. Various technical measures (such as doubleleaf gear
with ring torsion spring, gear with hairspring, and compensating spherical
hinge.) are adopted to eliminate the clearance of the mechanism and ensure
the stability of the rudder system.
5. Setting and type of locking mechanism. Locking mechanism is used to
reliably lock the control surface which is not working for a certain time,
such as the storage and transportation of missile until launching, or before
starting control, or before the separation of the first and second stages of
two-stage missile, and to reliably unlock it when needed. Generally, when
the precision of the electric lock on the return-to-zero line of the rudder
system is limited by the zero error of the rudder system and the moving gap
or the working state of the energy source, the special control surface locking
mechanism must be adopted. The locking mechanism of the control surface
of the second-stage missile must ensure that it is still locked reliably under
the maximum hinge moment in the first-stage flight. When separating, the
lock must be reliably unlocked under the corresponding hinge moment. If
the locking moment is insufficient, the control surface will be unlocked in
advance, which will eventually lead to the air disintegration of the missile.
9.1 Electro-Hydraulic Servo Control Technology of Aircraft Gas Turbine Pump
87