27 research outputs found
Flexible manipulator control experiments and analysis
Modeling and control design for flexible manipulators, both from an experimental and analytical viewpoint, are described. From the application perspective, an ongoing effort within the laboratory environment at the Ohio State University, where experimentation on a single link flexible arm is underway is described. Several unique features of this study are described here. First, the manipulator arm is slewed by a direct drive dc motor and has a rigid counterbalance appendage. Current experimentation is from two viewpoints: (1) rigid body slewing and vibration control via actuation with the hub motor, and (2) vibration suppression through the use of structure-mounted proof-mass actuation at the tip. Such an application to manipulator control is of interest particularly in design of space-based telerobotic control systems, but has received little attention to date. From an analytical viewpoint, parameter estimation techniques within the closed-loop for self-tuning adaptive control approaches are discussed. Also introduced is a control approach based on output feedback and frequency weighting to counteract effects of spillover in reduced-order model design. A model of the flexible manipulator based on experimental measurements is evaluated for such estimation and control approaches
Decentralized Blocking Zeros and Decentralized Strong Stabilization Problem
Cataloged from PDF version of article.This paper is concerned with a new system theoretic
concept, decentralized blocking zeros, and its applications in the
design of decentralized controllers for linear time-invariant finitedimensional
systems. The concept of decentralized blocking zeros
is a generalization of its centralized counterpart to multichannel
systems under decentralized control. Decentralized blocking zeros
are defined as the common blocking zeros of the main diagonal
transfer matrices and various complementary transfer matrices
of a given plant. As an application of this concept, we consider
the decentralized strong stabilization problem (DSSP) where the
objective is to stabilize a plant using a stable decentralized
controller. It is shown that a parity interlacing property should
be satisfied among the real unstable poles and real unstable
decentralized blocking zeros of the plant for the DSSP to be
solvable. That parity interlacing property is also suf6icient for the
solution of the DSSP for a large class of plants satisfying a certain
connectivity condition. The DSSP is exploited in the solution
of a special decentralized simultaneous stabilization problem,
called the decentralized concurrent stabilization problem (DCSP).
Various applications of the DCSP in the design of controllers for
large-scale systems are also discussed
Vehicular traffic flow at an intersection with the possibility of turning
We have developed a Nagel-Schreckenberg cellular automata model for
describing of vehicular traffic flow at a single intersection. A set of traffic
lights operating in fixed-time scheme controls the traffic flow. Open boundary
condition is applied to the streets each of which conduct a uni-directional
flow. Streets are single-lane and cars can turn upon reaching to the
intersection with prescribed probabilities. Extensive Monte Carlo simulations
are carried out to find the model flow characteristics. In particular, we
investigate the flows dependence on the signalisation parameters, turning
probabilities and input rates. It is shown that for each set of parameters,
there exist a plateau region inside which the total outflow from the
intersection remains almost constant. We also compute total waiting time of
vehicles per cycle behind red lights for various control parameters.Comment: 8 pages, 17 eps figures, Late
Variable Structure Control in Automotive Control Systems
This work presents a control design for an automotive antilock braking systems. Our approach is based on the sliding mode control concept. We formulate the problem of achieving minimum stopping distance as that of extremum searching in a highly uncertain situation when the optimized function is not known analytically but its output values can be observed on-line. For the braking problem the magnitude of the tire/road friction force is a maximized variable. It is considered to be an output of a nonlinear dynamic system which includes the model of mechanical motion and equations of the hydraulic circuit. This setting is complicated by the optimized variable (friction force) not being directly measurable. To overcome this difficulty a sliding mode observer was designed