This paper explores a novel approach to dexterous manipulation, aimed at levels of speed, precision, robustness, and simplicity suitable for practical deployment. The enabling technology is a Direct-drive Hand (DDHand) comprising two fingers, two DOFs each, that exhibit high speed and a light touch. The test application is the dexterous manipulation of three small and irregular parts, moving them to a grasp suitable for a subsequent assembly operation, regardless of initial presentation. We employed four primitive behaviors that use ground contact as a “third finger”, prior to or during the grasp process: pushing, pivoting, toppling, and squeeze-grasping. In our experiments, each part was presented from 30 to 90 times randomly positioned in each stable pose. Success rates varied from 83% to 100%. The time to manipulate and grasp was 6.32 seconds on average, varying from 2.07 to 16 seconds. In some cases, performance was robust, precise, and fast enough for practical applications, but in other cases, pose uncertainty required time-consuming vision and arm motions. The paper concludes with a discussion of further improvements required to make the primitives robust, eliminate uncertainty, and reduce this dependence on vision and arm motion.

Localizing contacts and collisions is an important aspect of failure detection and recovery for robots and can aid perception and exploration of the environment. Contrary to state-of-the-art methods that rely on forces and torques measured on the robot, this paper proposes a kinematic method for proprioceptive contact localization on compliant robots using velocity measurements. The method is validated on two planar robots, the quadrupedal Minitaur and the two-fingered Direct Drive (DD) Hand which are compliant due to inherent transparency from direct drive actuation. Comparisons to other state-of-the-art proprioceptive methods are shown in simulation. Preliminary results on further extensions to complex geometry (through numerical methods) and spatial robots (with a particle filter) are discussed.

Threaded fasteners are prevalent throughout modern manufacturing. Thus, as the demand for automation in manufacturing increases, so does the demand for automated threaded fastening systems. However, many fundamental issues and engineering challenges still hinder robustness in automation, particularly for smaller screws and critical product finishing requirements. This paper surveys the state of the art in threaded fastening automation and discusses open questions for further research. This survey covers the following areas: 1) fundamentals of threaded fastening, including basic concepts and definitions; 2) analysis of the entire assembly process (consisting of part feeding and orientation, pickup, alignment, and driving), including discussions of tools, control strategies, and other considerations; 3) failure modes and techniques to mitigate them; 4) threaded fastening systems and electromechanical approaches; and 5) open challenges and suggestions for future development. Understanding the current state of automation in threaded fastening will provide a foundation for researchers to advance this field.

Hundreds of billions of small screws are assembled in consumer electronics industry every year, yet reliably automating the screwdriving process remains one of the most challenging tasks. Two barriers to further adoption of robotic threaded fastening systems are system cost and technical challenges, especially for small screws. An affordable intelligent screwdriving system that can support online stage and result classification is the first step to bridge the gap. To this end, starting from a state transition graph of screwdriving processes and a labeled screwdriving dataset (1862 runs of M1.4 screws) on multiple sensor signals, we develop classification algorithms and perform sensor reduction. Fast and accurate result classifiers are developed using linear discriminant analysis, while a wrapper method for feature subset selection is used to identify the optimal feature subset and corresponding sensor signals to reduce cost. A stage classifier based on decision tree is developed using the optimal sensor subset. The stage classifier achieves high accuracy in realtime prediction of various stages when augmented with the state transition graph.

We give a system overview and initial experimental results for SIMbot (spherical induction motor based ballbot), a human-sized dynamically stable mobile robot with only two active moving parts. SIMbot is a qualitatively new kind of robot with the potential to drastically reduce mechanical complexity in human-sized mobile robots. SIMbot uses a novel spherical induction motor as its drive mechanism, which is mechanically simpler than other ballbot drive mechanisms. We demonstrate the feasibility of this innovation with experimental results for balancing, stationkeeping, short point-to-point motions, and recovery from initial lean angles.

This paper describes the design, construction, and operation of a closed-loop spherical induction motor (SIM) ball wheel for a balancing mobile robot (ballbot). Following earlier work, this new design has a smaller rotor and higher torques due to the use of six stators in a skewed layout. Actuation and sensing kinematics as well as control methods are presented. In its current implementation, torques of up to 8 Nm are produced by the motor with rise and decay times of 100 ms. Results are presented supporting its potential as a prime mover for mobile robots.