Algorithms for Automated Pointing of Cardiac Imaging Catheters

This paper presents a modified controller and expanded algorithms for automatically positioning cardiac ultrasound imaging catheters within the heart to improve treatment of cardiac arrhythmias such as atrial fibrillation. Presented here are a new method for controlling the position and orientation of a catheter, smoother and more accurate automated catheter motion, and initial results of image processing into clinically useful displays. Ultrasound imaging (intracardiac echo, or ICE) catheters are steered by four actuated degrees of freedom (DOF) to produce bi-directional bending in combination with handle rotation and translation. Closed form solutions for forward and inverse kinematics enable position control of the catheter tip. Additional kinematic calculations enable 1-DOF angular control of the imaging plane. The combination of positioning with imager rotation enables a wide range of visualization capabilities, such as recording a sequence of ultrasound images and reconstructing them into 3D or 4D volumes for diagnosis and treatment. The algorithms were validated with a robotic test bed and the resulting images were reconstructed into 3D volumes. This capability may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissues or working instruments. The methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control.Engineering and Applied Science

Design, fabrication and control of soft robots

Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.National Science Foundation (U.S.) (Grant IIS-1226883

Robust motion control of a soft robotic system using fractional order control

This paper has been presented at 26th International Conference on Robotics in Alpe-Adria-Danube Region (RAAD 2017)This work presents a novel control approach for a tendon-driven soft robotic system. The soft robotic system composed of a silicon continuum, tendons and antagonistic actuation yields a highly complex mechanical model. As the high complexity is not feasible here, a linear time invariant system is approximated instead for the controller design. A fractional order PDalfa controller is applied to meet performance and the high robustness requirements due to the neglected nonlinear dynamics. Simulation and experimental data confirm a superior performance of the FO controller while exhibiting a higher robustness to model mismatches and better disturbance rejection properties