@article{oai:repository.dl.itc.u-tokyo.ac.jp:00000089, author = {Arai, Hirohiko and Tachi, Susumu}, issue = {1}, journal = {IEEE transactions on industrial electronics : a publication of the IEEE Industrial Electronics Society}, month = {Feb}, note = {application/pdf}, pages = {15--20}, title = {Position control system of a two degree of freedom manipulator with a passive joint}, volume = {38}, year = {1991} }