1) S. Kawamura, K. Miyata, H. Hanafusa and K. Ishida: Proposal of a Hierarchical Feedback Control Scheme for Pneumatic Drive Systems, Proc. of U.S.A.-Japan Sympo. on Flexible Automation, Minneapolis, 175/180 (1988)
2) J.L. Shearer, et al.: Fluid Power Control, M.I.T. Press (1960)
3) M. Vidyasagar: Nonlinear System Analysis, Prentice-Hall (1978)
4) S. Arimoto and F. Miyazaki: Stability and Robustness of PD and PID Feedback Control with Gravity Compensation for Robot Manipulators, Proc. of ASME 1986 Winter Annual Meeting, Anaheim, 67/72 (1986)