Robot Builders

Simultaneous localization, mapping and moving object tracking (SLAMMOT) involves both simultaneous localization and mapping (SLAM) in dynamic environments and detecting and tracking these dynamic objects. In this paper, a mathematical framework is established to integrate SLAM and moving object tracking. Two solutions are described: SLAM with generalized objects, and SLAM with detection and tracking of moving objects (DATMO). SLAM with generalized objects calculates a joint posterior over all generalized objects and the robot. Such an approach is similar to existing SLAM algorithms, but with additional structure to allow for motion modeling of generalized objects. Unfortunately, it is computationally demanding and generally infeasible. SLAM with DATMO decomposes the estimation problem into two separate estimators. By maintaining separate posteriors for stationary objects and moving objects, the resulting estimation problems are much lower dimensional than SLAM with generalized objects. Both SLAM and moving object tracking from a moving vehicle in crowded urban areas are daunting tasks. Based on the SLAM with DATMO framework, practical algorithms are proposed which deal with issues of perception modeling, data association, and moving object detection. The implementation of SLAM with DATMO was demonstrated using data collected from the CMU Navlab11 vehicle at high speeds in crowded urban environments. Ample experimental results shows the feasibility of the proposed theory and algorithms.

The latest Talking Robots podcast interview is with Rudolf Bannasch, who seems to be single-handedly driving European research in Bionics. Professor at the Technical University in Berlin, Germany, coordinator of the German bionics competence network BIOKON, and founder of the startup company EvoLogics, he is a powerhouse of creativity when it comes to translating natural phenomena into engineering applications. He has studied penguins, mantas, dolphins and arctic birds, and then extracted key properties of these animals to optimize the performance of propellers, underwater modems, grippers, underwater vessels and aircraft (Turns out if you put penguins into wind-tunnels you are in for a real surprise - and yet another product for your startup!). Tune in for an overview of the state-of-the art and future in bionics, and for more information on Bannasch’s aqua-ray and air-ray robots, artificial penguins, or humanoid arms with fluidic muscles! -more-

In this paper, a tight coupling between computer vision and parallel robotics is exhibited through the projective line geometry. Indeed, contrary to the usual methodology where the robot is modeled independently from the control law that will be implemented, the proposed method takes into account, from the early modeling stage, the fact that vision will be used for control. Hence, kinematic modeling and projective geometry are fused into a control-devoted projective kinematic model. Thus, starting from a vision-based kinematic modeling of a Gough—Stewart manipulator, a visual servoing scheme is presented, where the image projection (edges) of the non-rigidly linked legs are servoed, rather than the end-effector pose or the leg directions.

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Researchers at the University of Bristol, UK, have shown that droplets of liquid can travel uphill when placed on a vertically vibrating inclined plate. ‘In fact, if the plate vibrates at the right rate, the droplets will always travel counter-intuitively up the incline.’ This very interesting discovery will not change the world, but it may lead to new methods to manipulate microscopic amounts of fluids.

The objective of this paper is to propose a new homography-based approach to image-based visual tracking and servoing. The visual tracking algorithm proposed in the paper is based on a new efficient second-order minimization method. Theoretical analysis and comparative experiments with other tracking approaches show that the proposed method has a higher convergence rate than standard first-order minimization techniques. Therefore, it is well adapted to real-time robotic applications. The output of the visual tracking is a homography linking the current and the reference image of a planar target. Using the homography, a task function isomorphic to the camera pose has been designed. A new image-based control law is proposed which does not need any measure of the 3D structure of the observed target (e.g. the normal to the plane). The theoretical proof of the existence of the isomorphism between the task function and the camera pose and the theoretical proof of the stability of the control law are provided. The experimental results, obtained with a 6 d.o.f. robot, show the advantages of the proposed method with respect to the existing approaches.

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The objective of this paper is to propose a new homography-based approach to image-based visual tracking and servoing. The visual tracking algorithm proposed in the paper is based on a new efficient second-order minimization method. Theoretical analysis and comparative experiments with other tracking approaches show that the proposed method has a higher convergence rate than standard first-order minimization techniques. Therefore, it is well adapted to real-time robotic applications. The output of the visual tracking is a homography linking the current and the reference image of a planar target. Using the homography, a task function isomorphic to the camera pose has been designed. A new image-based control law is proposed which does not need any measure of the 3D structure of the observed target (e.g. the normal to the plane). The theoretical proof of the existence of the isomorphism between the task function and the camera pose and the theoretical proof of the stability of the control law are provided. The experimental results, obtained with a 6 d.o.f. robot, show the advantages of the proposed method with respect to the existing approaches.

This paper presents a time invariant kinematic motion controller for wheeled mobile robots. Actuator capability, mechanical design, and traction forces governed by terrain features provide velocity and curvature limitations that are used in the design of the controller. A novel path manifold that considers curvature limitations is introduced to provide a desired path shape and convergence to the reference posture or trajectory. Lyapunov techniques are then used to derive a control law that asymptotically converges the robot to an arbitrarily small neighborhood of the path manifold. Posture regulation, path following, and trajectory tracking capability to a similarly scaled neighborhood of the target are provided. Controller parameters are optimized and initial conditions are identified that satisfy physical constraints of the robot and provide smooth commands. Curvature boundaries and asymptotic convergence naturally limit allowable initial conditions and are resolved by driving the robot to intermediate goal points within regions of allowable initial conditions. Posture regulation is evaluated in simulation and experiment on a Compliant Framed wheeled Modular Mobile Robot (CFMMR) for two different terrain surfaces. Trajectory tracking and path following of constant curvature references are evaluated in simulation and experiment, respectively.

Many of us, at least in developed countries, have CD players rusting in our homes. So why not turning them into something useful? A very short note by the American Chemical Society (ACS) says that Spanish researchers have adapted this now venerable technology into home health monitoring systems. This means that CD technology could be used for tests ranging from the measurement of environmental toxins to at-home disease diagnosis and even laboratory-based testing. The researchers don’t give any clues about the availability of such a product, but I think they’ve got a brilliant idea.

This paper presents a computer vision-based method for visually detecting the contact between an end-effector and a target surface under an optical microscope during microrobotic manipulation. Without using proximity or force/touch sensors, this method provides a submicrometer detection accuracy and possesses robustness. Fundamentally, after the establishment of contact in the world frame, further vertical motion of the end-effector (flexible or stiff) induces horizontal motion in the image plane. Contact between a micropipette tip and a glass slide in the scenario of microrobotic cell manipulation is used as an example to elaborate on the detection method. Experimental results demonstrate that the computer vision-based method is capable of achieving contact detection between the micropipette and the glass slide surface with an accuracy of 0.2 m. Furthermore, 1000 experimental trials reveal that the presented method is robust to variations in illumination intensity, microscopy magnification, and microrobot motion speed.

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