Robot Builders

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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A team of MIT faculty and researchers are working toward what could be the car of the future: a vehicle that drives itself, with people as passengers. Their vehicle passed a driving test last week during a visit by officials from the DARPA Urban Challenge competition. -more-

Another research team has found a way to use nanotechnology to deliver drugs. As you may know, polymeric nanoparticles are excellent carriers for delivering drugs. But as they are quickly removed from the blood, they are somewhat ineffective for the task. Now, researchers from the University of California at Santa Barbara (UCSB) have found that ‘nanoparticles can be forced to remain in the circulation when attached to red blood cells.’ In other words, these nanoparticles hitchhike on red blood cells. Apparently, these nanoparticles could stay with their hosts for their life time — about 120 days. So this could lead to new treatments for cancer or heart disease. But stay tuned, because this technique only works in the lab right now.

This paper proposes an algorithm that drives a unicycle type robot to a desired path, including obstacle avoidance capabilities. The path-following control design relies on Lyapunov theory, backstepping techniques and deals explicitly with vehicle dynamics. Furthermore, it overcomes the initial condition constraints present in a number of path-following control strategies described in the literature. This is done by controlling explicitly the rate of progression of a “virtual target” to be tracked along the path; thus bypassing the problems that arise when the position of the path target point is simply defined as the closest point on the path. The obstacle avoidance part uses the Deformable Virtual Zone (DVZ) principle. This principle defines a safety zone around the vehicle in which the presence of an obstacle induces an “intrusion of information” that drives the vehicle reaction. The overall algorithm is combined with a guidance solution that embeds the path-following requirements in a desired intrusion information function, which steers the vehicle to the desired path while the DVZ ensures minimal contact with the obstacle, implicitly bypassing it. Simulation and experimental results illustrate the performance of the control system proposed.

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Many of the terms dealt with by roboticists such as consciousness, emotion, and intelligences are notoriously difficult to define. Researchers Shane Legg and Marcus Hutter have put together a very interesting collection of over 70 definitions of intelligence (PDF format), creating the largest and most well-referenced such collection to date. With a little effort, I bet we could expand their list to twice the size! They’ve divided the list into collective definitions, psychologist’s definitions, and AI researcher’s definitions. Among the definers you’ll find Minsky, Schank, Warwick, Lenat, Feigenbaum and other well-known AI and robotics researchers. Definitely worth a read if this is a topic you wrangle with when designing your robots. -more-

Another research team has found a way to use nanotechnology to deliver drugs. As you may know, polymeric nanoparticles are excellent carriers for delivering drugs. But as they are quickly removed from the blood, they are somewhat ineffective for the task. Now, researchers from the University of California at Santa Barbara (UCSB) have found that ‘nanoparticles can be forced to remain in the circulation when attached to red blood cells.’ In other words, these nanoparticles hitchhike on red blood cells. Apparently, these nanoparticles could stay with their hosts for their life time — about 120 days. So this could lead to new treatments for cancer or heart disease. But stay tuned, because this technique only works in the lab right now. read story

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.

This paper explores a sensorless manipulation method for orienting and translating convex objects in the plane. The manipulation task is performed by a two-agent point-contact push. During the manipulation, each agent makes a point contact with the object, and both agents push together along a straight-line. One advantage of the two-agent point-contact push over the physical fence based push is that the two-agent point-contact push can manipulate non-polygonal parts, and reduce the position and orientation uncertainties simultaneously. First, two manipulation primitives are identified, equilibrium and non-equilibrium pushes, and the motion of the object characterized under these two pushing actions. Then, a controllability analysis is conducted for this class of manipulation using the theory of positive bases. After the analysis, the planning problem is studied in the framework of a switched system, and an analytical solution to the planning problem is developed. Finally, manipulation examples and experiments are provided to demonstrate the proposed manipulation method.

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.

In this short article, Popular Science reports that a Brown University team has developed a new imaging system. The CTX process combines ‘computed-tomography (CT) scanners, X-ray video and computer software to give doctors and researchers a 3-D look at bones in motion.’ In a previous note, the team said that ‘CTX technology is expected to deliver images with exceptional precision and detail. Researchers will be able to track 3-D skeletal movements with 0.1 millimeter accuracy and see the equivalent of 1,000 CT images per second.’ A commercial system should be ready by 2010.