Browsing by Subject "mobile robots"

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Open Access
A self-adjusting and modular supervisory control algorithm for planar dexterous manipulation
(Elsevier, 2023-04) Ristevski, Stefan; Çakmakçı, Melih
Many applications require precise handling and manipulation of delicate objects. In some cases, the object must be transported to a new location following a strict travel path including time-related constraints. This paper presents a self-adjusting modular control algorithm for dexterous manipulation of planar objects using multiple manipulators with precise path and timing deliveries. The popular caging approach is simple, and usually effective when manipulating objects with multiple devices but can fail following complex paths with orientation adjustments under time-critical tracking requirements. The proposed approach exploits the dynamics of the object in real-time using tracking control and allocates the force that needs to be applied by each manipulator based on their current position around the object to maximize their capability to push in the direction of the contact angle. The new algorithm is self-adjusting and modular; It can adjust its force allocation according to configuration changes during operation, and manipulators execute the same algorithm regardless of their number. The advantages of the new approach are successfully demonstrated both with simulations and testbed experiments, including orientation tracking, which is not typically featured with the caging approach. Conditions to check when the new algorithm is most effective are also analyzed. The closed-loop stability and performance of the new algorithm are also studied and necessary conditions are identified.
Open Access
A comparison of different approaches to target differentiation with sonar
(2001) Ayrulu (Erdem), Birsel
This study compares the performances of di erent classication schemes and fusion techniques for target di erentiation and localization of commonly encountered features in indoor robot environments using sonar sensing Di erentiation of such features is of interest for intelligent systems in a variety of applications such as system control based on acoustic signal detection and identication map building navigation obstacle avoidance and target tracking The classication schemes employed include the target di erentiation algorithm developed by Ayrulu and Barshan statistical pattern recognition techniques fuzzy c means clustering algorithm and articial neural networks The fusion techniques used are Dempster Shafer evidential reasoning and di erent voting schemes To solve the consistency problem arising in simple ma jority voting di erent voting schemes including preference ordering and reliability measures are proposed and veried experimentally To improve the performance of neural network classiers di erent input signal representations two di erent training algorithms and both modular and non modular network structures are considered The best classication and localization scheme is found to be the neural network classier trained with the wavelet transform of the sonar signals This method is applied to map building in mobile robot environments Physically di erent sensors such as infrared sensors and structured light systems besides sonar sensors are also considered to improve the performance in target classication and localization.