We present a new mechanical design for a 3-DOF haptic device with spherical kinematics (pitch, yaw, and prismatic radial). All motors are grounded in the base to decrease inertia and increase compactness near the user's hand. An aluminum-aluminum friction differential allows for actuation of pitch and yaw with mechanical robustness while allowing a cable transmission to route through its center. This novel cabling system provides simple, compact, and high-performance actuation of the radial DOF independent of motions in pitch and yaw. We show that the device's capabilities are suitable for general haptic rendering, as well as specialized applications of spherical kinematics such as laparoscopic surgery simulation.

This paper presents a new algorithm for selecting the optimal needle insertion point in images of hand veins for robotic IV insertion. The 3D coordinates and orientation of the vein that the algorithm detects would eventually be fed to a robot for insertion of the IV needle. The goal of the algorithm is to identify venous bifurcations and determine an insertion point and approach angle for the needle in between their branches. The algorithm uses an annular tracking window that tracks along the veins and searches for bifurcations. We describe methods for centering the initial bifurcation estimates, error-checking, and positioning the needle exactly in between the bifurcation branches. We conclude with an experimental study of 50 subjects that shows a 32.4% success rate at detecting all bifurcations and a 82.6% success rate at finding at least one bifurcation in each image that contains bifurcations.

We present a series of experiments which explore the use of consumer-grade accelerometers as joint position sensors for robotic manipulators. We show that 6- and 7-dof joint angle estimation is possible by using one 3-d accelerometer for each pair of joints. We demonstrate two calibration approaches and experimental results using accelerometer-based control in both position-control and torque-control regimes. We present a manipulator design combining accelerometer-based sensing with low-cost actuation, and conclude by demonstrating the utility of consumer-grade accelerometers even on high-precision manipulators.