磁性液体触觉传感器的设计及特性研究

Design and characteristics research on the magnetic fluid tactile sensor

磁性液体兼具液体材料的流动性和固体材料的磁性,能够在重力场和磁场的作用下长期稳定存在。磁性液体具有独特的一阶浮力特性,在磁场梯度的作用下能够悬浮起比自身密度大的非磁性物体。基于磁性液体的一阶浮力特性,设计了一种新型的磁性液体触觉传感器。当接触压力作用在悬浮触棒的非磁性触点时,悬浮触棒的移动将引起霍尔元件处的磁场变化,进而输出电压信号。该结构能够进行接触压力、表面轮廓和微小位移的同时测量。该触觉传感器体积小,相比于传统的硅片式触觉传感装置成本更低。磁性液体相比于固体材料来说,能够在系统中起到缓冲吸能的作用,进而提高了传感器系统的耐冲击性。在0~0.09 N的接触压力测量范围内,测量精度能够达到10-2 N量级,灵敏度3.34 V/N,线性度误差3.4%,迟滞误差1.4%,分辨率1.1%F.S.。

Magnetic fluid has both the fluidity of liquid materials and the magnetism of solid materials, which can exist stably for a long time under the action of gravitational field and magnetic field. The unique first-order buoyancy principle of magnetic fluid makes it could suspend non-magnetic objects, whose density is higher than itself, under the action of magnetic field gradient. Based on the first-order buoyancy principle of magnetic fluid, a novel magnetic fluid tactile sensor is designed. When the contact pressure acts on the non-magnetic point of the suspended rod, the movement of the suspended rod will cause the change of magnetic field at the Hall element. Then, the output voltage signal will change accordingly. The structure can be used for simultaneous measurement of contact pressure, surface profile and micro displacement. Compared with the traditional silicon wafer, the tactile sensor has small size and low cost. In addition, the magnetic liquid can absorb energy in the system, which can help to improve the impact resistance of the sensor system. Within the contact pressure measurement range of 0~0.09 N, the measurement accuracy can reach in order of 10-2 N. The sensitivity is 3.34 V/N, the linearity error is 3.4%, the hysteresis error is 1.4%, and the resolution is 1.1% F.S.