Independent Researcher, Sapporo 063-0867, Japan.
Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan.
Sensors (Basel). 2022 Oct 19;22(20):7989. doi: 10.3390/s22207989.
Advances in micro-electro-mechanical systems technology have led to the emergence of compact attitude measurement sensor products that integrate acceleration, magnetometer, and gyroscope sensors on a single chip, making them important devices in the field of three-dimensional (3D) attitude measurement for unmanned aerial vehicles, smartphones, and other devices. Sensor fusion algorithms for posture measurement have become an indispensable technology in cutting-edge research, such as human posture measurement using wearable sensors, and stabilization problems in robot position and posture measurement. We have also developed wearable sensors and powered suits in our previous research. We needed a technology for the real-time measurement of a 3D human body motion. It is known that quaternions can be used to algebraically handle 3D rotations; however, sensor fusion algorithms for three sensors are presently complex. This is because these algorithms deal with the post-rotation attitude (pure quaternions) rather than rotation information (the rotor) to avoid a double covering problem involving the rotor. If we are dealing with rotation, it may be possible to make the algorithm simpler and faster by dealing directly with the rotor. In this study, to solve the double covering problem involving the rotor, we propose a stateful rotor and develop a technique for uniquely determining the time-varying states of the rotor. The proposed stateful rotor guarantees the continuity of the rotor parameters with respect to angular changes, and this paper confirms its effectiveness by simulating two rotations around an arbitrary axis. In addition, we verify experimentally that a fast sensor fusion method using stateful rotor can be used for attitude calculation. Experiments also confirm that the calculated results converge to the desired rotation angle for two spatial rotations around an arbitrary axis. Since the proposed stateful rotor extends and stabilizes the definition of the rotor, it is applicable to any algorithm that deals with time-varying quaternionic rotors. In this research, an algorithm based on a multiply-add operation is designed to reduce computational complexity as a high-speed calculation for embedded systems. This method is theoretically equivalent to other methods, while contributing to power saving and the cost reduction of products.
微机电系统技术的进步使得紧凑的姿态测量传感器产品得以出现，这些产品将加速度计、磁力计和陀螺仪传感器集成在单个芯片上，成为无人机、智能手机和其他设备三维（3D）姿态测量领域的重要设备。姿态测量的传感器融合算法已经成为前沿研究中不可或缺的技术，例如使用可穿戴传感器进行人体姿态测量，以及在机器人位置和姿态测量中的稳定问题。在我们之前的研究中，我们还开发了可穿戴传感器和动力服。我们需要一种用于实时测量 3D 人体运动的技术。众所周知，四元数可用于代数处理 3D 旋转；然而，目前三个传感器的传感器融合算法比较复杂。这是因为这些算法处理的是经过旋转的姿态（纯四元数），而不是旋转信息（转子），以避免涉及转子的双重覆盖问题。如果我们处理的是旋转，那么直接处理转子可能会使算法更简单、更快。在这项研究中，为了解决涉及转子的双重覆盖问题，我们提出了一种有状态的转子，并开发了一种技术来唯一确定转子的时变状态。所提出的有状态转子保证了转子参数相对于角度变化的连续性，本文通过模拟围绕任意轴的两次旋转来验证其有效性。此外，我们通过实验验证了使用有状态转子的快速传感器融合方法可用于姿态计算。实验还证实，对于围绕任意轴的两个空间旋转，所计算的结果收敛到期望的旋转角度。由于所提出的有状态转子扩展和稳定了转子的定义，因此它适用于处理时变四元数转子的任何算法。在这项研究中，设计了一种基于乘法-加法运算的算法，以降低计算复杂度，作为嵌入式系统的高速计算。该方法在理论上与其他方法等效，同时有助于节省电力和降低产品成本。
