Concentric Tube Robots (CTRs) have been proposed to operate within the unstructured environment for minimally invasive surgeries. In this letter, we consider the operation scenario where the tubes travel inside the channels with a large clearance or large curvature, such as aortas or industrial pipes. Accurate kinematic modeling of CTRs is required for the development of advanced control and sensing algorithms. To this end, we extended the conventional CTR kinematics model to a more general case with large tube-to-tube clearance and large centerline curvature. Numerical simulations and experimental validations are conducted to compare our model with respect to the conventional CTR kinematic model. In the physical experiments, our proposed model achieved a tip position error of 1.53 mm in the 2D planer case and 4.36 mm in 3D case, outperforming the state-of-the-art model by 71% and 66%, respectively.

A robotic surgical device has learned to autonomously navigate inside a beating heart. Using only a small camera for vision, it successfully travelled to the correct location in the hearts of pigs for surgeons to then complete the operation. Pierre Dupont at Harvard Medical School in Boston and his colleagues created a robotic catheter --a thin tube widely used in surgeries to deliver devices or drugs. The device has a camera and LED light on its tip and is connected to a motor system that controls its movement from the other end. The team used 2000 images of the interior of a heart to train an algorithm to control the movement of the catheter.

The pig looks like any other pig, only it's been wearing a backpack for a week--in the name of science. Just behind its head sits a control box, with a battery and processor, from which runs a cable that enters through the pig's flank. Once inside, the cable attaches to a very special robot clamped onto the pig's esophagus, the pathway to the stomach. Little by little, the robot lengthens, in turn lengthening the tube. The robot attached to a segment of esophagus.

You don't see self-driving cars taking over American cities yet, but robotic tractors already roar through our corn and soybean farms, helping to plant and spray crops. They also gather huge troves of data, measuring moisture levels in the soil and tracking unruly weeds. Combine that with customized weather forecasts and satellite imagery, and farmers can now make complex decisions like when to harvest--without ever stepping outside. These tools are part of a new trend, known as "precision agriculture," that is transforming how we grow crops. Using everything from sensors on combines to drones equipped with infrared cameras that monitor plant health, service providers--ranging from Monsanto and DuPont to startups--take data from the fields, upload it to the cloud, crunch it, and provide farmers with advice on how to run their operations.