Current Issue : July - September Volume : 2016 Issue Number : 3 Articles : 4 Articles
This study proposes the use of a split covariance intersection algorithm (Split-CI) for decentralized multirobot cooperative\nlocalization. In the proposed method, each robot maintains a local cubature Kalman filter to estimate its own pose in a predefined\ncoordinate frame.When a robot receives pose information from neighbouring robots, it employs a Split-CI based approach to fuse\nthis received measurement with its local belief. The computational and communicative complexities of the proposed algorithm\nincrease linearly with the number of robots in the multirobot systems (MRS).The proposed method does not require fully connected\nsynchronous communication channels between robots; in fact, it is applicable for MRS with asynchronous and partially connected\ncommunication networks. The pose estimation error of the proposed method is bounded. As the proposed method is capable\nof handling independent and interdependent information of the estimations separately, it does not generate overconfidence state\nestimations.The performance of the proposed method is compared with several multirobot localization approaches.The simulation\nand experiment results demonstrate that the proposed algorithm outperforms the single-robot localization algorithms and achieves\napproximately the same estimation accuracy as the centralized cooperative localization approach, but with reduced computational\nand communicative cost....
A primary requirement in distributed robotic software systems is the dissemination of data to all interested collaborative\nentities in a timely and scalable manner. However, providing such a service in a highly dynamic and resource limited\nrobotic environment is a challenging task, and existing robot software infrastructure has limitations in this\naspect. This paper presents a novel robot software infrastructure, micROS-drt, which supports real-time and scalable\ndata distribution. The solution is based on a loosely coupled data publish-subscribe model with the ability to support\nvarious time-related constraints. And to realize this model, a mature data distribution standard, the data distribution\nservice for real-time systems (DDS), is adopted as the foundation of the transport layer of this software infrastructure.\nBy elaborately adapting and encapsulating the capability of the underlying DDS middle ware, micROS-drt can meet\nthe requirement of real-time and scalable data distribution in distributed robotic systems. Evaluation results in terms\nof scalability, latency jitter and transport priority as well as the experiment on real robots validate the effectiveness of\nthis work....
The paper presents a motion planning method of redundant manipulator for painting uniform thick coating on the interior\nof irregular duct of some air crafts. Discontinuous peripheral painting method is employed by analyzing the restrictions during\npainting the duct. For improving the longitudinal uniformity of thick coating, the interlacing painting method plans two sets of\nsweeping paths and an interlacing distance between the starting paths of the two times of painting. The interlacing distance and\noverlapping distance are optimized by establishing and analyzing the model of longitudinal uniformity. To enhance the transverse\nuniformity, sweeping speeds for curved surfaces are calculated by the ratio of transfer efficiency after the basic sweeping speed for\nthe plane is determined. The intertwining method, minimizing the sum of the weighed distances between the duct centerline and\nkey points of the manipulator links, is employed for the joint trajectory planning without collision. The simulation and experiment\nresults show that the redundant manipulators can finish painting the internal surface of the irregular S-shaped duct without\ncollision. The maximum relative deviation is 16.3% and the thicknesses of all measurement points satisfy the acceptance criteria of\nthe factory....
In order to spray onto the canopy of interval planting crop, an approach of using a target spray robot with a composite vision servo\nsystem based on monocular scene vision and monocular eye-in-hand vision was proposed. Scene camera was used to roughly\nlocate target crop, and then the image-processing methods for background segmentation, crop canopy centroid extraction, and\n3D positioning were studied. Eye-in-hand camera was used to precisely determine spray position of each crop. Based on the\ncenter and area of 2D minimum-enclosing-circle (MEC) of crop canopy, a method to calculate spray position and spray time was\ndetermined. In addition, locating algorithm for the MEC center in nozzle reference frame and the hand-eye calibration matrix were\nstudied.The processing of a mechanical arm guiding nozzle to spray was divided into three stages: reset, alignment, and hovering\nspray, and servo method of each stage was investigated. For preliminary verification of the theoretical studies on the approach, a\nsimplified experimental prototype containing one spray mechanical arm was built and some performance tests were carried out\nunder controlled environment in laboratory. The results showed that the prototype could achieve the effect of ââ?¬Å?spraying while\nmoving and accurately spraying on target.ââ?¬Â...
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