This paper presents a new version of the camera-spacemanipulation method (CSM). The set of nonlinear view parameters of the classic CSM is replaced with a linear model. Simulations and experiments show a similar precision error for the two methods. However, the new approach is simpler to implement and is faster.Index Terms-Camera matrix, camera-space manipulation (CSM), pinhole camera model, robot control, vision-based control.
This article presents an iterative procedure for improving the precision obtainable with camera-space manipulation. It also reports on extensive experimental results using this procedure with a task of some historical note in the area of vision-guided robotics, a task that involves close-tolerance, 3D, rigid-body assembly. The procedure was devised to achieve higher pre cision by introducing to parameter estimates the accuracy of the "perspective" camera model, while retaining the numerical advantage of the orthographic model. The camera-space coor dinates of each of several visually detected cues on the grasped object are multiplied by an iteratively improved correction fac tor, so that the modified image-plane appearances of the cues more closely approach the ideal of an orthographic projection. The correction factor is normalized near the point of maneuver termination so that camera-space maneuver objectives may stay unchanged. A similar strategy may be used to determine the camera-space objectives themselves. Results of experimental and simulation studies are presented and discussed.
This paper focuses on the design of P -δ controllers for single-input-single-output (SISO) linear timeinvariant (LTI) systems. The basis of this work is a geometric approach allowing to partitioning the parameter space in regions with constant number of unstable roots. This methodology defines the hyperplanes separating the aforementioned regions and characterizes the way in which the number of unstable roots changes when crossing such a hyper-plane. The main contribution of the paper is that it provides an explicit tool to find P -δ gains ensuring the stability of the closed-loop system. In addition, the proposed methodology allows to design a non-fragile controller with a desired exponential decay rate σ. Several numerical examples illustrate the results and a haptic experimental setup shows the effectiveness of P -δ controllers.
In this paper the workspace and payload capacity of a new design of reconfigurable Delta-type parallel robot is analysed. The reconfiguration is achieved by adjusting the length of the kinematic chains of a given robot link simultaneously and symmetrically during the operation of the robot. This would produce a dynamic workspace in shape and volume. A numerical analysis of the variation of shape and volume of the workspace and payload capacity of the robot is presented. Based both on the results of this analysis and on practical requirements, a proposal for the design of a reconfiguring mechanism is presented.
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