并联式六维加速度传感器的误差及容错处理

Error and fault-tolerant processing of parallel type six-axis accelerometer

基于解耦算法研究了并联式六维加速度传感器的误差特性和容错策略。通过引入"辅助角速度"的概念,并借助于四元数将旋转参量扩展至四维空间,得到了两个形式简单的递推公式,实现了六维加速度的完全解耦。通过剖析解耦机理,找到了影响解耦精度的3类误差源,并分析了它们的产生原因。通过构建辅助角速度误差与源误差、输出误差之间的映射关系,推导出了3组基本误差方程的解析表达式,据此揭示了各误差因素的影响规律。仿真试验与数学推导的结果吻合得较好,验证了误差方程及规律的有效性。从尺度约束的角度挖掘出弹性体拓扑构型中隐藏的变形协调条件,推导出了3个力协调方程,由此给出了一种可解决93个组合故障问题的容错处理方案。样机试验结果显示,局部支链出现故障后重构系统的综合解耦误差不超过8.5%,基本满足测量要求,验证了容错处理方案的可行性,同时也表明并联式六维加速度传感器具备一定的鲁棒性。

On the basis of decoupling algorithm, the error characteristics and fault-tolerance strategy of a parallel type six-axis accelerometer were researched. By introducing an aided angular velocity and using quaternion to describe rotation parameters in a four-dimensional space, two explicit recursive formulas with simple forms were obtained, and six-axis accelerations were entirely decoupled. By analyzing the decoupling mechanism, three kinds of error sources affecting the decoupling precision were obtained, and the reasons that cause the error were analyzed. By establishing the mapping relations between the error of aided angular velocity, source errors and output errors, the analytical expressions of the basic error equations were derived, and then the influence rules of error components were revealed. The verification experiment shows that the mathematical results are well consistent with the simulation ones in ADAMS, and the relative error between them is acceptable. Three force coordination equations were derived by establishing the hidden deformation compatibility conditions of elastomeric topological configuration, and then a fault-tolerant processing scheme was proposed to solve 93 combined failures. Experimental results indicate that the maximum relative error is 8. 5 after using the new algorithm to decouple the six-axis acceleration of the systems with partial failures, which meets the accuracy requirements. Above results verify that the influence rules of errors and the scheme of fault-tolerant processing are both correct and feasible, and also demonstrate that the parallel type six-axis aceelerometer has some level of robustness.