空间探测原子磁强计的主动磁补偿实验

在空间探测过程中,采用高灵敏无自旋交换弛豫(SERF)原子磁强计在行星表面进行磁场测量是原位物质成分分析的有效手段之一。为了提高SERF原子磁强计的磁场测量灵敏度,必须减小外界磁场扰动对其原子自旋SERF态质量的影响,基于SERF原子磁强计的测量原理,设计了一套主动磁补偿系统。首先,通过测量驱动激光光强获得3个方向的磁场信息;在此基础上,控制电流源和线圈主动产生一个与外界磁场扰动大小相同、方向相反的磁场来补偿扰动,以提高原子自旋SERF态的质量;最后,结合现有的SERF原子磁强计实验平台进行了实验验证。实验结果表明,与手动补偿方式相比,采用本文所述的主动磁补偿系统,可以实时跟踪磁场补偿点,降低系统信号的噪声,补偿了外界磁场的扰动,验证了磁强计主动磁补偿技术的有效性,为后续样机的研制奠定了技术基础。     

Micro powder injection molding of boron carbide components with SiC-Al2O3-Y2O3 sintering additives

Sintering additives and micro-powder injection molding offer an effective method to densify boron carbide（B₄C） and make B₄C components with complex shapes. By adjusting the proportion of three kinds of powders（SiC, Al₂O₃ and Y₂O₃）, four kinds of sintering additives were prepared. The feedstock uniformity, debinding behavior, phase composition and microstructure of micro injection molded B₄C components with different sin...     

Workspace,stiffness analysis and design optimization of coupled active-passive multilink cable-driven space robots for on-orbit services

The use of space robots (SRs) for on-orbit services (OOSs) has been a hot research topic in recent years. However, the space unstructured environment (i.e.: confined spaces, multiple obstacles, and strong radiation interference) has greatly restricted the application of SRs. The coupled active-passive multilink cable-driven space robot (CAP-MCDSR) has the characteristics of slim body, flexible movement, and electromechanical separation, which is very suitable for extreme space environments. However, the dynamic and stiffness modeling of CAP-MCDSRs is challenging, due to the complex coupling among the active cables, passive cables, joints, and the end-effector. To deal with these problems, this paper proposes a workspace, stiffness analysis and design optimization method for such type of MCDSRs. Firstly, the multi-coupling kinematics relationships among the joint, cables and the end-effector are established. Based on hybrid series-parallel characteristics, the improved coupled active–passive (CAP) dynamic equation is derived. Then, the maximum workspace, the maximum stiffness, and the minimum cable tension are resolved, among them, the overall stiffness is the superposition of the stiffness produced by the active and the passive cable. Furthermore, the workspace, the stiffness, and the cable tension are analyzed by using the nonlinear optimization method (NOPM). Finally, an 8-DOF CAP-MCDSR experiment system is built to verify the proposed modeling and trajectory tracking methods. The proposed modeling and analysis results are very useful for practical space applications, such as designing a new CAP-MCDSR, or utilizing an existing CAP-MCDSR system.