Autonomous robot-assisted active catheter insertion using image guidance.
ABSTRACT In this paper, we investigate autonomous robot- assisted insertion of an active catheter instrumented with shape memory alloy (SMA) actuators using image guidance. An Augmented Hybrid Impedance Control (AHIC) algorithm is implemented on a Mitsubishi robot (PA 10-7C) to insert the active catheter. The robot is constrained to move in Cartesian space along a pre-defined trajectory while controlling the force of insertion. A closed-loop control scheme has been developed to accurately control the bending in the active catheter. The tip of the active catheter is tracked in real-time to provide information on the path of the catheter and for determining the future course of insertion. The catheter is autonomously guided from the point of entry to the site of plaque buildup, thereby shielding the surgeon from the harmful radiation due to the X-rays used for imaging, providing a more ergonomic approach for catheter insertion. Experimental results are given to illustrate the robot-assisted catheter insertion procedure.
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ABSTRACT: Continuum manipulators are gaining widespread acceptance in commercial robotics, particularly in the medical field, where their compliance allows a large benefit for patient safety. However, this compliance also makes precise position control of these manipulators quite difficult. This paper presents two closed-loop control implementations applied to a small scale continuum manipulator. These implementations are both based on manipulator tip position feedback from an electromagnetic sensor. The command tracking and disturbance rejection properties of the two control implementations are shown to be approximately equivalent, and provide improved position control when compared to open-loop control, without sacrificing system stability.Proceedings - IEEE International Conference on Robotics and Automation 01/2012;
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ABSTRACT: Calculating leakage inductances between windings of multi-winding Traction transformers is one of the most important schemes in design procedure. In this paper, analytical and finite element methods (FEM) have been introduced for electromagnetic modeling of traction transformers with four pancake split windings. Using these models, the leakage inductances between the split windings are calculated and the models have been validated with the help of experimental data gathered from a typical 4000kV A cast-resin dry-type transformer. Some reformations are employed to improve the FEM results and effects of these reformations on accuracy of the model are studied. Employing the validated models, the effects of middle yoke on the leakage inductances of split winding traction transformers are discussed in this paper.ECTI-EEC. 02/2012;
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ABSTRACT: Continuum manipulators offer a means for robot ma-nipulation in a constrained environment, where the manipulator body can safely interact with, comply with, and navigate around obstacles. However, obstacle interactions impose constraints that conform the robot body into arbitrary shapes regardless of ac-tuator positions. Generally, these effects cannot be wholly sensed on a continuum manipulator and, therefore, render model-based controllers incorrect, leading to artificial singularities and unstable behavior. We present a task-space closed-loop controller for contin-uum manipulators that does not rely on a model and can be used in constrained environments. Using an optimal control strategy on a tendon-driven robot, we demonstrate this method, which we term model-less control, which allows the manipulator to interact with several constrained environments in a stable manner. To the best of our knowledge, this is the first work in controlling continuum manipulators without using a model.IEEE Transactions on Robotics 08/2014; 30(4):880-888. · 2.57 Impact Factor