车辆IMU软测量技术精度分析

Accuracy analysis of vehicle IMU soft sensing technology

摘要:

为节约半主动悬架电气架构和电子控制单元(ECU)的开发流程,提出一种新的半主动悬架传感器布置方案,并给出最佳惯性测量单元(IMU)安装位置。建立通过IMU信号解算4个簧上位置加速度的精确与完备公式,选择合适的角转动次序和参考系来保证解算方法的正确性；利用最优化理论及偏导数方法结合不同的悬架权重研究传感器安装位置对软测量精度的影响,并给出了有约束条件下的最优安装位置。实验结果表明:新提出的传感器布置方案及运动学解算方法可以很好地预测4个簧上位置处的垂向加速度,并具有较高的稳定性,但是安装在不同位置处的解算精度差异较大；通过最优化理论得出的有约束最佳安装理论位置的实验结果与理论符合(均方根误差约为0.6 m·s^-2),相比于其他安装位置,最佳安装位置处的实验结果对不同工况均具有较高的稳定性及测量精度；相比于水平安装位置,IMU的垂向位置对最终的解算结果和精度有较大的影响。采用数形结合思想给出了一个IMU安装位置误差等值椭球面,用该椭球面可以较为清楚直观地对安装位置进行分析。

Abstract:

To save the semi-active suspension electrical architecture and ECU development process, a new semi-active suspension sensor layout scheme is proposed, and the optimal IMU installation position is given. An accurate and complete formula for calculating the acceleration of four sprung positions by IMU signal is established. The proper angular rotation order and reference frame are selected to ensure the correctness of the method. The influence of sensor mounting position on soft sensing accuracy is given by using optimization theory and partial derivative method combined with different suspension weights, and the optimal mounting position with constraints is given. The experimental results show that the new sensor arrangement scheme and kinematics solution method can well predict the vertical acceleration of four sprung positions and have high stability, but the solution accuracy of different positions is quite different. The experimental results of the constrained optimal installation position obtained by the optimization theory are consistent with the theory (the root mean square error is about 0.6 m·s^-2). Compared with other installation positions, the experimental results of the optimal installation position have higher stability and measurement accuracy for different working conditions. Compared with the horizontal installation position, the vertical position of IMU has a greater impact on the final solution results and accuracy. An equivalent error ellipsoid of IMU installation position is given with combination of quantities and spatial forms, which can analyze the installation position more clearly and intuitively.