Excessive recoil severely restricts the loading of high-power traditional guns on modern vehicles. To reduce the recoil without breaking the continuous firing mode and reducing the projectile velocity, a recoil reduction method that controls the lateral ejecting of propellant gas by a piston was proposed. The recoil reduction device is symmetric about the barrel axis. First, a one-dimensional two-phase flow model of interior ballistic during the gun firing cycle was established. Next, the MacCormack scheme was used to simulate, and the piston motion was gained. Then the propagation of the rarefaction wave in the barrel was presented. Finally, the propulsion difference between the piston-controlled gun and the traditional gun was discussed. The results showed that the recoil momentum was reduced by 31.80%, and the muzzle velocity was decreased by just 1.30% under the reasonable matching of structural parameters.

This paper presents a miniature Linear Series Elastic Actuator (LSEA), in which two low-cost linear potentiometers were adopted to achieve a compact design. To improve the measurement accuracy of the linear potentiometer, a novel Bezier-based Calibration Method (BCM) and its optimization method were proposed to calibrate the inherent nonlinearity of the linear potentiometer. Calibration efficiency of the BCM was investigated numerically by making a comparison with the widely used Polynomial Calibration method (PCM), and the effect of the BCM calibration on the control performance of the LSEA was investigated experimentally by displacement and force control. Results reveal that the BCM exhibits an excellent local calibration ability for the nonlinearity with knee points. Due to the above characteristic, the BCM could produce a better calibration accuracy than the PCM under the same model order and improve the control performance of the LSEA. In addition, the BCM could calibrate the inherent nonlinearity of the potentiometer in a continuous form rather than that of piecewise ones. The continuous calibration form could bring more convenience to practical applications.

A new recoil reduction method of gun was proposed in this work to reduce the recoil without reducing the muzzle velocity and changing the continuous firing mode. Its recoil reduction mechanism was studied based on the two-phase flow theory. First, combining the gas-solid two-phase flow in the barrel, the electromagnetic control in the electromagnetic valve, the fluid-solid coupling in the piston cavity, and the transient gas flow in the exhaust pipe, an eight-stage mathematical model of the gun propulsion process was established. Next, the propagation law of the rarefaction wave in the barrel was discussed. Then, the propulsion difference between the gun proposed here and the traditional gun was presented. The results showed that the proposed method could reduce the recoil impulse by 38.20% without reducing the muzzle velocity under reasonable matching of the structural parameters.

Excessive recoil severely restricts the application of high-power traditional guns on modern aircraft. The objective of the proposed dual-chamber dispersed charging high-pressure opening and low-pressure replying gas-guide self-locking control rear spray scheme is to address the shortcomings of existing lateral-nozzle weapons, which are unable to control the opening and replying of the rear spray channel. This results in the inefficient utilization of powder gas and a short duration of continuous rear spray. The scheme aims to further reduce the recoil impulse of the weapon by optimizing the opening and replying of the rear spray channel. In light of the two-phase flow of powder gas within the dual chamber, the gas-guide self-locking channel and lateral rear nozzle, coupled with the gas-solid coupling effect of the two spring-slider systems of the valve and the locking pin, a mathematical model is proposed. A model of the firing process of a 30 mm cannon with dispersed charging, gas-guide, and self-locking control rear spray has been established. The flow field in the two chambers and lateral rear nozzle, as well as the motion law of the valve and the locking pin, have been obtained. A further comparison is made with the firing process of a two-chamber weapon with a fixed-pressure valve, with the objective of analyzing the influence of the gas-guide self-locking control on the duration and total impulse of the powder gas post-spray. The results demonstrate that in comparison to existing dual-chamber fixed-pressure weapons, the dual-chamber gas-guide self-locking control post-spray weapon increases the post-spray duration from 4.682 to 7.434 ms, thereby extending the post-spray. The duration of the powder gas post-spray is increased by 58.78 %, while the total post-spray impulse rises from 414.12 to 454.77 N s. This results in a reduction of the weapon recoil impulse by 29.34 %. This study further reduces the weapon recoil impulse of the dual-chamber rear spray while simultaneously controlling the opening and resetting of the rear spray channel. This makes the design of the dual-chamber rear spray a more practical method of reducing the recoil impulse.

Using Dynamic Vibration Absorber (DVA) to suppress the vibration of slender structure is promising for its reliable, efficiency and low cost. The main purpose of this study is to suppress the beam vibration by simultaneously optimizing DVA position, mass, damping and stiffness of a DVA-beam system. The motion equations of the DVA-beam system are derived first using the Rayleigh-Ritz method and Lagrange’s equation. Then the Particle Swarm Optimization is then applied to seek the DVA optimal parameters. In which the objective is to minimize the RMS value of the beam tip deflection in a specific time domain. The PSO performance is investigated in three kinds of beam load conditions, that is free vibration, beam subjected to pulse excitation and harmonic excitation. It is observed that in these optimizations the objective function converges quickly. Based on the optimal DVA parameters, the dynamic responses of the optimal DVA-beam system are analyzed and compared with those of bare beam. The results demonstrate that the optimal designed DVA can effectively suppress the beam vibration.