การนำทางการเคลื่อนที่หนึ่งองศาอิสระของแขนโดยใช้การป้อนกลับด้วยการสั่นสะเทีอนชนิดสัมผัส / พงศธร ศรอำพล = One-dof arm movement guidance using vibrotactile feedback / Pongstorn Sornumpol
The most serious problem for visually impaired persons is the lack of surrounding information. Vibrotactile signal applying to skin is an alternative solution which could supply them with necessary data to overcome this difficulty. However, since sensing bandwidth of the skin is restrictive in receiving information, it is more practical to use a small amount of simple data which is also easy to understand for this purpose. This research illustrated a feedback control method of one-dof arm movement guidance using a vibrotactile actuator. A mathematical model corresponding to arm movement in response to vibrotactile signal was created from frequency responses of 10 subjects with normal vision. The vibrotactile actuator is capable of producing up to 50 Hz signal. The subjects were given a learning period by using a closed loop P-controller to guide the arm from one reference position to another. The responses were estimated using a transfer function containing a gain, an integrator, and a time delay. However,the values of the gain and the time-delay for each individual are not consistent and vary with time. The model was constructed to design a feedback guidance system. It was found that a PD guidance system combined with a dead zone is appropriate for guiding arm movements to the desired locations with accuracy in a short period of time.
