Robot Builders

As computer chips are getting smaller and smaller, it becomes crucial to find new ways to connect them. Canadian researchers have developed a method to produce self-assembled nanowires that are 5,000 times longer than they are wide. They’ve been able to obtain nanowires measuring only 10 nanometers in width, but with a length of 50 microns. These nanowires could be used in about 10 years or more when the semiconductor industry reaches the 10-nanometer limit.

Pseudo-admittance is introduced as a novel bilateral telemanipulation system that is designed to mimic proportional-velocity admittance control on systems where the master is an impedance-type robot. The controller generalizes to systems with slave robots of the impedance or admittance type. Pseudo-admittance uses a proxy with admittance dynamics combined with direct force feedback from the slave, resulting in unique properties that mimic admittance control and exhibit tremor attenuation and quasi-static transparency. Pseudo-admittance control has potential benefits for tasks that require better-than-human levels of precision, as well as with systems that are typically run under rate control. The controller can also be modified to include virtual fixtures that provide guidance during task execution, while leaving ultimate control of the system with the operator. Guidance virtual fixtures could be used as macros that increase both speed and precision on structured tasks that require direct human control. The properties of the system are verified through simulations and experiments.

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The next version of Red Hat’s Fedora Linux will offer a feature called Fedora Electronic Laboratory that should be of interest to robotics and electronics hobbyists. Fedora Electronic Lab will include free software for ASIC and VLSI design, verilog and VHDL hardware design, SPICE simulation, PCB layout, schematic capture, timing and waveform visualization, 3D layout visualization, and microcontroller programming tools including Atmel AVR and PIC tools. Many of the free software tools were already available but required compilation or complex installation to use. Now they’ll be available to all Fedora Linux users without any extra work. A LiveCD version will also be available. Over 250 Universities are know to already use the VLSI tools in this collection, so having a complete Linux distro with the tools included should be a big time saver. Fedora Electronic Lab is largely the result of efforts by Chitlesh Goorah to collect useful existing free software for electronic engineers.

This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. When both sensors are integrated in a system their relative pose needs to be determined. The rotation between the camera and the inertial sensor can be estimated, concurrently with camera calibration, by having both sensors observe the vertical direction in several poses. The camera relies on a vertical chequered planar target and the inertial sensor on gravity to obtain a vertical reference. Depending on the setup and system motion, the translation between the two sensors can also be important. Using a simple passive turntable and static images, the translation can be estimated. The system needs to be placed in several poses and adjusted to turn about the inertial sensor centre, so that the lever arm to the camera can be determined. Simulation and real data results are presented to show the validity and simple requirements of the proposed methods.

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In this paper, an algorithm for autonomous stair climbing with a tracked vehicle is presented. The proposed method achieves robust performance under real-world conditions, without assuming prior knowledge of the stair geometry, the dynamics of the vehicle’s interaction with the stair surface, or lighting conditions. The approach relies on fast and accurate estimation of the robot’s heading and its position relative to the stair boundaries. An extended Kalman filter is used for quaternion-based attitude estimation, fusing rotational velocity measurements from a 3-axial gyroscope, and measurements of the stair edges acquired with an onboard camera. A two-tiered controller, comprised of a centering- and a heading-control module, utilizes the estimates to guide the robot rapidly, safely, and accurately upstairs. Both the theoretical analysis and implementation of the algorithm are presented in detail, and extensive experimental results demonstrating the algorithm’s performance are described.

Using NASA satellite imagery, researchers at the University of South Florida (USF) in St. Petersburg have found that it is possible to monitor coastal water quality. This means that water quality can be checked daily rather than monthly as done by traditional methods which involves expensive boat surveys. This information can be crucial for resource managers devising restoration plans for coastal water ecosystems. According to the researchers, this method can be applied to coastal waters worldwide with little changes — providing that resource managers have access to data from NASA satellites. read story

The integration of visual and inertial sensors for human motion tracking has attracted significant attention recently, due to its robust performance and wide potential application. This paper introduces a real-time hybrid solution to articulated 3D arm motion tracking for home-based rehabilitation by combining visual and inertial sensors. Data fusion is a key issue in this hybrid system and two different data fusion methods are proposed. The first is a deterministic method based on arm structure and geometry information, which is suitable for simple rehabilitation motions. The second is a probabilistic method based on an Extended Kalman Filter (EKF) in which data from two sensors is fused in a predict-correct manner in order to deal with sensor noise and model inaccuracy. Experimental results are presented and compared with commercial marker-based systems, CODA and Qualysis. They show good performance for the proposed solution.

Robotics Engineer Chris Schur has documented his research into mobile robot docking. The discussion includes beacon and sensor selection and usage, techniques for successfully navigating to a charging station, and ideas about the mechanical and electrical aspects of the docking connection itself.

As one of the methods for reducing the work of programming, the Learning-from-Observation (LFO) paradigm has been heavily promoted. This paradigm requires the programmer only to perform a task in front of a robot and does not require expertise. In this paper, the LFO paradigm is applied to assembly tasks by two rigid polyhedral objects. A method is proposed for recognizing these tasks as a sequence of movement primitives from noise-contaminated data obtained by a conventional 6 degree-of-freedom (DOF) object-tracking system. The system is implemented on a robot with a real-time stereo vision system and dual arms with dexterous hands, and its effectiveness is demonstrated.