Assistance of virtual space manipulation by means of novel pseudo-force feedback devices

基于触觉信息比本体感觉信息在触觉识别中的作用更大这一发现，提出了一种伪力反馈方法，该方法通过收紧每个指尖来诱导触觉。该方法的概念是将显示感觉限制为仅限于触觉，而不是传统的力反馈设备通过施加实际反作用力来刺激触觉和本体感觉受体。采用高电压初始加速脉冲开环控制器对样机进行控制，减小了装置延迟。样机的紧固力可达2.3N。使用者感觉到的反作用力与所施加的接触力相关。样机的两指抓取装置成功地识别了从10 mm到70 mm的大范围的虚拟物体。在此基础上，提出了一种具有伪力反馈功能的虚拟物体操纵系统原型，该系统由握指伪力反馈装置、通用物理模拟器和虚拟联轴器组成。为了仿真的稳定性和清晰的接触感觉，虚拟耦合被分成两个部分。使用由虚拟耦合产生的力向量和虚拟手指的速度来检测操纵对象与另一对象的碰撞。撞击力大致是通过增加手指紧固力来表现的。实验结果表明，伪力反馈提供了更逼真的抓握感觉，减少了对虚拟物体的渗透，这表明指尖收紧装置具有伪力展示的潜力，伪力展示是辅助虚拟空间操作的有效手段。

Based on the finding that tactile information has larger role in haptic recognition than proprioceptive information, a pseudo-force-feedback method was proposed that induces tactile sense to each fingertip by its tightening. The concept of the method is limiting the display sense to tactile alone, in contrast to the conventional force-feedback devices stimulate both tactile and proprioceptive receptors by applying actual reaction force. The prototype device was controlled with open-loop controller with high-voltage initial acceleration pulse to reduce the device delay. The prototype device attained the tightening force up to 2.3N. The perceived reaction force sense by the users correlated with the applied contact force. The prototype two-fingered grasping device demonstrated that the wide range of virtual objects, from 10 to 70mm, were successfully recognized. The subjective sensation of grasping was more resemble to actual objects than the substitutive method using vibration.Further more, a virtual objects manipulation system with pseudo-force-feedback function was prototyped that consists of pseudo-force-feedback devices by finger-tightening, a general-purpose physical simulator and virtual couplings. The virtual coupling was divided into two components for simulation stability as well as clear contact perception. Collision of the manipulating object with another object was detected using the force vectors generated by the virtual couplings and velocity of the virtual fingers. The collision-force was approximately displayed by increasing finger-tightening force. Experimental trials demonstrated that pseudo-force-feedback provides more realistic grasping sensation and reduces penetration into virtual objects.These results suggested that fingertip tightening device has a potential of pseudo-force-display, and pseudo-force-display is effective for assisting virtual space manipulation.