论文标题
稀疏磁力计的无惯性运动跟踪 - 双铰链关节系统中可观察性的条件
Sparse Magnetometer-free Inertial Motion Tracking -- A Condition for Observability in Double Hinge Joint Systems
论文作者
论文摘要
惯性测量单元通常用于越来越多的应用领域,以跟踪或捕获运动链的运动,例如人类四肢,外骨骼或机器人致动器。一个主要的挑战是磁干扰的存在,导致磁力计读数不可靠。最近的研究表明,可以通过剥削运动学约束来克服这个问题。尽管运动链的每个段通常都配备了IMU,但一种称为稀疏惯性运动跟踪的新方法旨在从减少的传感器集的测量值中推断出完整的运动状态。在目前的贡献中,我们将无磁力计和稀疏方法结合在一起,以实时运动跟踪具有非平行关节轴的双铰链关节系统。分析系统的可观察性,我们找到了一个条件,该条件可以确保所有段之间的相对取向由运动构成的唯一确定,而运动约束仅包含陀螺仪读数。此外,我们提出了一个移动性估计器,并在对具有不同兴奋程度的三个运动的模拟研究中验证它。这项研究的结果证实了所有理论上的猜想,并证明在精确而简单的激发条件下,无磁力计稀疏惯性实时运动跟踪是可行的。
Inertial measurement units are commonly used in a growing number of application fields to track or capture motions of kinematic chains, such as human limbs, exoskeletons or robotic actuators. A major challenge is the presence of magnetic disturbances that result in unreliable magnetometer readings. Recent research revealed that this problem can be overcome by exploitation of kinematic constraints. While typically each segment of the kinematic chain is equipped with an IMU, a novel approach called sparse inertial motion tracking aims at infering the complete motion states from measurements of a reduced set of sensors. In the present contribution, we combine the magnetometer-free and the sparse approach for real-time motion tracking of double-hinge joint systems with non-parallel joint axes. Analyzing the observability of the system, we find a condition which assures that the relative orientations between all segments are uniquely determined by a kinematic constraint, which contains only the gyroscope readings. Furthermore, we propose a moving-horizon estimator and validate it in a simulation study of three movements with different degrees of excitation. The results of this study confirm all theoretical conjectures and demonstrate that magnetometer-free sparse inertial real-time motion tracking is feasible under precise and simple excitation conditions.