Measurement of Six Degrees of Freedom Head Kinematics in Impact Conditions Employing Six Accelerometers and Three Angular Rate Sensors (6aω Configuration)
Measurement of Six Degrees of Freedom Head Kinematics in Impact Conditions Employing Six Accelerometers and Three Angular Rate Sensors (6aω Configuration)
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DOI：
10.1115/1.4005427
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发表时间：
2011-11-01
影响因子：
1.7
通讯作者：
Bolte, John H.
中科院分区：
文献类型：
--
作者：
Kang, Yun-Seok;Moorhouse, Kevin;Bolte, John H.
在汽车碰撞条件下测量六自由度(6 DOF)头部运动学的能力对于评估头颈部负荷以及脑损伤是重要的。提出了一种在短时冲击条件下精确获取六自由度头部运动学的方法，并进行了验证。该方法使用六个加速度计和三个角速率传感器(6a欧米伽配置)，从而使用代数方程来确定相对于物体固定的坐标系的角加速度，并且直接测量角速度，而不是对角加速度进行数值积分。在低速(2.3m/S)和高速度(4.0m/S)两种碰撞条件下，利用混合III型假人的内部9个加速度计测头和提出的6a欧米伽方案进行了头部碰撞试验，以验证该方法的有效性。将6a omega方法与9个加速度计阵列传感器组件(NAP)以及由3个加速度计和3个角速度传感器(3a Omega)组成的配置进行了比较，这两种配置都通常用于测量头部的6个自由度运动学，以评估脑和颈部损伤。通过计算归一化均方根偏差(NRMSD)来量化三种方法(6a欧米伽、3a欧米伽和NAP)精确测量6自由度头部运动学的能力，NRMSD提供了随时间变化的平均百分比误差。头部碰撞试验结果表明，在低速和高速碰撞条件下，所提出的6a omega方案能够产生与NAP方案相当的角加速度和线加速度。结果发现，在高速头部撞击条件下，由于所需的数值差分，3a欧米伽格式不能提供精确的角加速度或转换到远程位置的线加速度。6a欧米伽和3a欧米伽方案都能够测量准确的角位移，而NAP仪器由于双重数值积分而无法产生准确的角位移。建议的6a omega方案似乎能够在任何严重的撞击条件下测量头部的准确6自由度运动学。[DOI：10.1115/1.4005427]
The ability to measure six degrees of freedom (6 DOF) head kinematics in motor vehicle crash conditions is important for assessing head-neck loads as well as brain injuries. A method for obtaining accurate 6 DOF head kinematics in short duration impact conditions is proposed and validated in this study. The proposed methodology utilizes six accelerometers and three angular rate sensors (6a omega configuration) such that an algebraic equation is used to determine angular acceleration with respect to the body-fixed coordinate system, and angular velocity is measured directly rather than numerically integrating the angular acceleration. Head impact tests to validate the method were conducted using the internal nine accelerometer head of the Hybrid III dummy and the proposed 6a omega scheme in both low (2.3 m/s) and high (4.0 m/s) speed impact conditions. The 6a omega method was compared with a nine accelerometer array sensor package (NAP) as well as a configuration of three accelerometers and three angular rate sensors (3a omega), both of which have been commonly used to measure 6 DOF kinematics of the head for assessment of brain and neck injuries. The ability of each of the three methods (6a omega, 3a omega, and NAP) to accurately measure 6 DOF head kinematics was quantified by calculating the normalized root mean squared deviation (NRMSD), which provides an average percent error over time. Results from the head impact tests indicate that the proposed 6a omega scheme is capable of producing angular accelerations and linear accelerations transformed to a remote location that are comparable to that determined from the NAP scheme in both low and high speed impact conditions. The 3a omega scheme was found to be unable to provide accurate angular accelerations or linear accelerations transformed to a remote location in the high speed head impact condition due to the required numerical differentiation. Both the 6a omega and 3a omega schemes were capable of measuring accurate angular displacement while the NAP instrumentation was unable to produce accurate angular displacement due to double numerical integration. The proposed 6a omega scheme appears to be capable of measuring accurate 6 DOF kinematics of the head in any severity of impact conditions. [DOI: 10.1115/1.4005427]