1. (1) R. M. Inigo and R. M. Kossey: “Closed-Loop Control of a Manipulator Arm Using a Wrist Force Sensor”, IEEE Trans. on Indu. Elect., Vol. IE-34, No. 8., pp. 371-378 (1987)
2. (2) A. Bicchi and G. Tonietti: “Fast and Soft-arm Tactics”, IEEE. Robot. Automat. Mag., Vol. 11, pp. 22-33 (2004)
3. (4) S. Katsura, Y. Matsumoto, and K. Ohnishi: “Modeling of Force Sensing and Validation of Disturbance Observer for Force Control”, IEEE Trans. on Indu. Elect., Vol. 54, No. 2, pp. 530-538 (2007)
4. (5) S. Sakaino, T. Sato, and K. Ohnishi: “A Stability Analysis of Force Control Based on Momentum”, T. IEE Japan, Vol. 129-D, No. 6, pp. 614-621 (2009) (in Japanese)