Measurement of Resultant Acceleration of a Moving Object in 3-D Space Based on Sensing Position of A Metallic Ball Rolling in a Spherical Shell

本文研究的是一种智能加速度传感器，它可以对三维空间中运动的物体进行平衡感知。实际上，我们已经开发了一种传感器，可以测量三维空间中运动加速度和重力的合成，该传感器是基于对位于球壳内部弹性层上的金属球的位置的传感。介绍了不同类型硅橡胶弹性层的构造，并利用赫兹定律计算了其对压力的位移。由于由此产生的加速度使球朝着在壳中找到平衡位置的方向滚动，因此金属球的中心位置是要追求的目标。弹性层与壳体同心，易变形，因此三个高频振荡型接近传感器可以检测球抗压沉降。给出了利用沉降对压力特性提取加速度的测量原理。通过对不同橡胶的实验结果进行比较，得出最合适的传感器设计方案。这些数据对于制定球面加速度传感器的规格具有重要意义。我们得到的实际数据表明，角度误差小于7.4[度]；量误差小于0.097[m/s^2]；力灵敏度0.089[N]；不敏感范围小于6.1[度]，几乎没有振动。

This research is concerned with a smart acceleration sensor which makes it possible to give equilibrium sense on a object moving in a 3-d space. Actually, we have developed a sensor which can measure resultant acceleration of motion and gravity in 3D space based on sensing a metallic ball position on elastic layer located at inside of a spherical shell. Construction of different types of elastic layers by silicon rubber is introduced and their displacements against pressure are calculated by using the Hertz' law. Since the resultant acceleration makes the ball roll toward the direction to find a balanced position in the shell, the center position of the metallic ball is the target to be pursued. The elastic layer is concentric to the shell and liable to distort so that three proximity sensors of high-frequency oscillation type can detect ball sink against pressure. We show measurement principle of extracting the acceleration by using the characteristics of the sink versus pressure. Experimental results are shown and compared among various rubbers to have the most appropriate design of the sensor. These data are important for making specifications of the spherical acceleration sensor. We got practical data such that angular error less than 7.4[deg] ; amount error less than 0.097[m/s^2] : force sensitivity 0.089[N] ; insensible range less than 6.1[deg] with almost no vibration.