无人机自驾仪硬件加固方案设计与可靠性分析

自驾仪是无人机实现自主飞行与自主完成各项任务的核心器件。现有商用无人机自驾仪大多没有进行硬件加固,直接用来执行重大任务时有一定风险。通过分析可知自驾仪组成模块中对安全性和可靠性影响最大的模块为控制解算器。根据逐步提高的容错需求,使用复位器、计数器、反相器、选择器等简单器件以及在芯片内部添加简单代码,分别设计了单机复位加固方案、双机热备加固方案、硬件切换和软件切换双机互备加固方案。重点研究了加固方案的可靠性随时间的变化关系,并进行了对比分析。对加固方案的工作机制进行了模拟,分析了这些方案在处理故障时的系统异常输出时间等容错特性。计算表明,这些加固方案可以显著提高系统的可靠性,其中双机互备加固方案的可靠性最高。该研究对于指导高可靠性自驾仪设计时在容错效果与复杂度、成本等方面进行折中具有较大的参考意义。

Hardware Reinforcement Designs and Reliability Analyses of UAV Autopilots

The autopilot is the crucial device of an UAV to implement autonomous flights and missions. Most of the existing commercial autopilots have no hardware reinforcement, which will lead to a risk in carrying out some significant tasks. The control resolver is analyzed as the module which performs the greatest impact on the security and the reliability in the composing of an autopilot. With the increasing fault-tolerance requirements, 4 reinforcements are respectively designed, namely, the single resolver reset reinforcement, the dual resolver hot backup reinforcement, and the dual host systems switched by hardware and software. Several simple devices such as reset chips, counters, inverters and selectors, and additional codes inside the resolvers are used to build the reinforcements. The reliabilities varying with time of the reinforcements are emphatically studied. With the simulation of the working mechanisms, the fault-tolerance performances such as the abnormal output durations of the reinforcements in fault treatments are analyzed. The calculations show that all the reinforcements can obviously enhance the reliability of the autopilot, of which the dual host systems increase the most. This research provides a meaningful direction to the tradeoff of the fault-tolerance performance, complexity, and cost in high reliability autopilot designs.