Component synthesis vibration suppression method of two component forces for flexible spacecraft

Considering the characteristics of two component forces on component synthesis vibration suppression(CSVS) method, two theorems on two component forces suppressing fractional multiple design frequency are given respectively. Meanwhile, the control force, which is composed by two arbitrary component forces with different initial time, can suppress certain frequencies for secondorder undamped vibration system. Using the above theorems, control moment of jet attitude maneuver on flexible spacecraft is designed on the basis principle of CSVS method. The simulations validate the correctness and effectiveness of the proposed method.     

NEW OPTIMAL LARGE ANGLE MANEUVER STRATEGY FOR SINGLE FLEXIBLE LINK

INTRODUCTIONTo accommodate the requirement of lightweight,for many machine systems, such as flexiblemanipulator, large solar array and flexible antennas ofspacecraft, flexibility has become an imPOrtantcharacteristic. But flexible vibration can degrade badlythe peforance and the precision of flexible systems.Control of vibration becomes very important asdesigners attempt to push the state of the art withfaster and lighter machines systems. Researchers haveexammed many different controlle…     

基于分力合成方法的航天器闭环反馈控制

为了增强分力合成主动振动抑制方法抵抗外界干扰的能力,将分力合成方法与闭环反馈控制相结合同时进行设计.用非约束模态级数方法建立解耦的姿态动力学方程和挠性附件振动方程,通过选取合适的反馈量,在设计闭环反馈参数时将挠性附件的振动和分力合成方法同时加入到约束条件中,得到最佳性能解.通过对单挠性杆模型的仿真,在满足系统各项性能指标的条件下,调整时间较分步设计方法明显减少,证明本文方法的有效性.     

FLEXIBLE SPACECRAFT VIBRATION SUPPRESSION USING PWPF MODULATED INPUT COMPONENT COMMAND AND SLIDING MODE CONTROL

This paper presents a dual‐stage control system design method for the rotational maneuver and vibration stabilization of a spacecraft with flexible appendages. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. The design of attitude controller was based on sliding mode control (SMC) theory leading to a discontinuous control law. This controller accomplishes asymptotic attitude maneuvering in the closed‐loop system and is insensitive to the interaction of elastic modes and uncertainty in the system. The shaped command input controller based on component synthesis vibration suppression (CSVS) method is designed for reduction of flexible mode vibration, which only requires information about natural frequency and damping of the closed system. Additionally, to extend the CSVS method to the system with on‐off actuators, pulse‐width pulse‐frequency (PWPF) modulation is employed to control the thruster firing and integrated with the CSVS method. Simulation results have been proven the potential of this technique to control flexible spacecraft.     

低开关频率下同步CSVS的电流谐波特性分析

在高电压-大电流的大功率牵引传动系统中,驱动逆变器受到开关损耗和散热条件等的限制,逆变器的最高工作开关频率通常只有几百赫兹。为了提高逆变器的输出性能,通常在中频段采用同步调制策略。针对同步SVPWM,总结了满足半周期奇对称HWS(half-wave odd symmetry)、1/4周期偶对称QWS(quarter-wave even symmetry)和三相对称3PS (quarter-wave even symmetry)的对称性规律,介绍了其中的同步CSVS的脉冲生成规律及发波方式。通过阻感负载下的仿真和实验,对同步CSVS的电流谐波特性进行分析,得到了电流谐波含量随调制比的变化规律以及电流谐波主要集中次数的分布规律,为同步CSVS的应用提供了一定的参考价值。     

分力合成和智能材料相结合的振动控制方法

针对采用喷气控制的挠性航天器大角度姿态机动的振动抑制问题,提出了一种将分力合成(CSVS)和基于分布式压电陶瓷元件(PZT)振动控制相结合的主动振动抑制方法.研究了将分力合成方法应用于闭环系统的控制.为了将CSVS方法应用于具有常幅值执行机构的系统,提出将PWPF调制与CSVS相结合的方法.为了进一步抑制挠性附件的残余振动,采用分布压电陶瓷元件(PZT)作为作动器,设计正位置反馈(PPF)补偿器,增加挠性结构振动模态的阻尼,使得挠性结构的振动在较短的时间内能够迅速衰减.最后,将该方法应用于挠性航天器的单轴rest-to-rest姿态机动控制,结果验证了该方法的可行性和有效性.     

Maneuver and vibration reduction of flexible spacecraft using sliding mode/command shaping technique

The current trend of spacecraft is to use large,complex, and light-weight space structures to achieveincreased functionality at a reduced lunch cost. Thisresults in these space structures being extremely flexibleand having lowfundamental vibration modes, and thesemodes are often excited during normal on-orbit opera-tions, such as attitude maneuvers, and so on, especial-ly, when the spacecraft attitude control system employson-off thrusters that produce discontinuous and nonlin-ear control actio…