Development of a 6-DOF force display system using ER actuators with high-safety. - Junji Furusho; Chengqiu Li; Xinghao Hu; Naoto Shichi; Takehito Kikuchi; Akio Inoue; Kenji Nakayama; Yuhei Yamaguchi; Ushio Ryu (VRCIA, 2006)