Authors:
Li Zhang,
Bijoy K. Ghosh,
Volume: 1, Page 2515 Paper number 501
Abstract:
In this paper, a novel 3D structure estimation approach is proposed.
The uniqueness of the approach lies in the fusion of vision and 2D
range, which is a common sensor combination for mobile robots. 2D range
information can be used for hypothesizing 3D structures, feature association,
and improving the estimate accuracy. These problems are difficult to
solve if using only vision. The proposed approach will be beneficial
to 3D map building application of the mobile robots. Experimental results
validate the effectiveness of the approach.
Authors:
Peter I. Corke,
Seth A. Hutchinson,
Volume: 1, Page 2521 Paper number 502
Abstract:
In image-based visual servo control, where control is effected with
respect to the image, there is no direct control over the Cartesian
velocities of the robot end effector. As a result, the robot executes
trajectories that are desirable in the image, but which can be indirect
and seemingly contorted in Cartesian space. In this paper we describe
the cause of these phenomena, and introduce a new partitioned approach
to visual servo control that overcomes the problem. In particular,
we decouple the z-axis rotational and translational components of the
control from the remaining degrees of freedom. Then, to guarantee that
all features remain in the image throughout the entire trajectory,
we incorporate a potential function that repels feature points from
the boundary of the image plane. We illustrate our new control scheme
with a variety of simulation results.
Authors:
Ruggero Frezza,
Claudio Altafini,
Volume: 1, Page 2527 Paper number 503
Abstract:
In this paper, we describe a predictive control law for an aircraft
autonomous approach to landing based on active vision. The path following
problem and the control of the pan-tilt unit that holds the on-board
camera are both formulated geometrically in the frameworks of SE(3)
and on the sphere S^2.
Authors:
João P. Hespanha,
Volume: 1, Page 2533 Paper number 504
Abstract:
This paper deals with the problem of driving the position of a point-robot
to a goal point, using measurements provided by a single camera. The
camera can be moved to compensate for the ambiguity in depth. It is
shown that, although the system consisting of the point robot together
with the moving camera is observable, there is no output-feedback controller
capable of asymptotically stabilizing an equilibrium point of the closed-loop
system. However, it is possible to design a controller that drives
the robot to the goal, provided that the position of the camera does
not converge. We give a hybrid controller---combining logic-based switching
with continuous dynamics---that accomplishes this. The stability of
the controller is also analyzed when there is miscalibration between
the robot and the camera.
Authors:
Allen Tannenbaum,
Volume: 1, Page 2539 Paper number 505
Abstract:
In this paper, we consider some general ideas for a theory of controlled
active vision. We will use as a model problem that of tracking, in
particular tracking eye movements. We will indicate that one can treat
this problem by using adaptive and robust control in conjunction with
multiscale methods from signal processing, and shape recognition theory
from computer vision. Tracking is a basic control problem in which
we want the output to follow or track a reference signal, or equivalently
we want to make the tracking error as small as possible relative to
some well-defined criterion (say energy, power, peak value, etc.).
Even though tracking in the presence of a disturbance is a classical
control issue, the problem at hand is very difficult and challenging
because of the highly uncertain nature of the disturbance. There are
a number of tracking problems that can easily be considered in a university
environment and which could act as benchmarks for testing various algorithms.
For example, one could consider the eye movement tracking problem in
the context of a man-computer interface. The techniques which we will
discuss should have a wide range of applicability in a number of tracking
problems including those in robotics, remotely controlled vehicles,
and pilot tracking helmets currently being developed.
Authors:
Mario Sznaier,
Brian Murphy,
Octavia I. Camps,
Volume: 1, Page 2545 Paper number 506
Abstract:
Recent hardware developments have rendered controlled active vision
a viable option for a broad range of practical problems. However,
realizing this potential requires having a framework for synthesizing
robust active vision systems, capable of moving beyond carefully controlled
environments. Recent work has shown that this can be achieved by combining
robust computer vision and control techniques. However, in some cases
robustness is achieved at the expense of performance. In this paper
we show that this performance loss can be avoided by recasting the
problem into a Linear Parameter Varying (LPV) form and using recently
developed robust identification and control tools for this class of
problems. These results are experimentally validated using a Bisight
robotic head.
|