System performance can be significantly improved when both the design of the plant and of the controller are considered concurrently. Control theory can be applied to a broad variety of systems, including those that are physical in nature and many that are not. Despite the generality of control theory, there are many situations in which opportunities are missed for using less conservative control laws and simpler overall implementations. This is due to the use of formulations that do not explicitly reveal the existence of intrinsic information pertaining to the particular domain of application. Such is the case with many physical systems. However, the various constraints associated with physical reality (in the form of principles, laws, etc.) open up several possibilities which can be exploited for system design and control. In this paper, we propose the Reciprocal Variable Feedback principle as a means for facilitating the control of plants with complicated nonlinear dynamics in the presence of parameter and/or structural uncertainty. The RVF principle exploits the effort-flow relationships associated with power interactions in order to assist in the design and control of physical processes. This is accomplished by using appropriate sensors instead of computation based on models (e.g., feedback linearization) and can be implemented within many physical domains. A motion control example is used to provide insight into the nature of the principle. It is expected that in the future, additional principles will be identified and introduced for integrating design with the control of dynamical systems.

1.
Astro¨m, K. J., and Wittenmark, B., 1984, Computer Controlled Systems: Theory and Design, Prentice-Hall, Englewood Cliffs, NJ.
2.
Axelby
G. S.
, ed.,
1959
, “
Control Concept
,”
IRE Trans. on Automatic Control
, Vol.
AC-4
, No.
1
, pp.
1
2
.
3.
Eveleigh, V. W., 1967, Adaptive Control and Optimization Techniques, McGraw-Hill, New York, NY.
4.
Friedland, B., 1975, “The Problem of the Gap,” Proc. IEEE Conference on Decision and Control, Houston, TX, p. 268.
5.
Gogoussis, A., 1989, “Solutions to the Frictional Dynamics Problem and the Reciprocal Variable Feedback Methodology for Design and Control of Robot Mechanisms,” Ph.D. thesis, Dept. of Mechanical Engineering, University of Minnesota.
6.
Gogoussis
A.
, and
Donath
M.
,
1993
, “
Determining the Effect of Coulomb Friction on the Dynamics of Bearings and Transmissions in Robot Mechanisms
,”
ASME Journal of Mechanical Design
, Vol.
116
(
2
), pp.
231
240
.
7.
Hogan, N., 1987, “Beyond Regulators: Modeling Control Systems as Physical Systems,” Proc. American Control Conference, Minneapolis, MN, Vol. 2, pp. 1468–1476.
8.
Horowitz, I. M., 1963, Synthesis of Feedback Systems, Academic Press, New York, NY.
9.
Kokotovic, P., 1975, “Focus on Modelling,” Proc. IEEE Conference on Decision and Control, Houston, TX, p. 269.
10.
Paynter, H. M., 1960, Analysis and Design of Engineering Systems, MIT Press, Cambridge, MA.
11.
Vossoughi, G., 1992, “Achieving Robust Performance for Electrohydraulic Servo Systems: an H-infinity/mu-Synthesis Solution for Manipulation and Contouring,” Ph.D. thesis, Dept. of Mechanical Engineering, University of Minnesota.
This content is only available via PDF.
You do not currently have access to this content.