Search

A walking control algorithm is generally a mixture of various controllers; it depends on the characteristics of the target system. Simply adopting one part of another researcher's algorithm does not guarantee an improvement in walking performance. However, this paper proposes an effective algorithm that can be easily adopted to other biped humanoid robots; the algorithm enhances the walking performance and stability of the robot merely by adjusting the walking-ready posture. The walking performance of biped humanoid robots is easily affected by an unsuitable walking-ready posture in terms of accuracy and repeatability. More specifically, low accuracy for the walking-ready posture may cause a large difference between an actual biped robot and its mathematical model, and the low repeatability may disturb the evaluation of the performances of balance controllers. Therefore, this paper first discusses the factors that detrimentally affect bipedal walking performance and their phenomena in the walking-ready posture. The necessary conditions for an ideal walking-ready posture are then defined based on static equilibrium and a suitable adjustment algorithm is proposed. Finally, the effectiveness of the algorithm is verified through dynamic computer simulations. [ABSTRACT FROM AUTHOR]

In this paper, the boundary coverage of known environments is investigated using multiple microrobots (MMR) involved in a distributed inspection case study. A strong need for an operator is able to control and receive feedback from microrobots. However, communication range is limited because of the size effect of microrobot, and obstacles may also prevent microrobots from communicating. To enable MMR to accomplish coverage task while maintaining the network connectivity with a base station, we propose a market-based boundary coverage algorithm. This algorithm can dynamically allocate the boundary coverage task to a microrobot, so as to adapt to the change of communication network topology. A motion control model based on virtual spring–damper system is established to prevent communication network splitting by monitoring infrared link quantity information among microrobot nodes. Simulations and experimental results, obtained using our MMR tested in a distributed inspection case study, demonstrate that the proposed solution fulfills the objective of maintaining network connectivity at all times while completing the allocated boundary coverage task. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a new cooperation control algorithm for stabilizing and trajectory tracking of an unmanned electric bicycle. The simplified model of the bicycle with the balancer is derived from Lagrangian and non-holonomic constraints with respect to translation and rotation relative to the ground plane. The stabilizing control and trajectory control of an autonomous bicycle are derived independently based on the simplified model. The balancing control is derived based on the output-zeroing controller. The steering and balancer for stabilizing the bicycle are used when the linear velocity is zero or the system starts up. It is shown that a balancing control using both the steering and the balancer has a better performance than conventional ones with only balancer or steering. The trajectory tracking control is derived by an input-output linearization approach to track the path in the ground plane. The steering and the back wheel are used to design the trajectory control. The coupling of the steering between the balancing control and the trajectory control are set by weighting gain. The balancing and the trajectory control have been implemented with the real bicycle by using MATLAB XPC-TARGET. An autonomous electric bicycle can be controlled remotely via a host PC. Numerical simulation and experimental results are shown to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

In this paper, we propose an algorithm for simultaneous indoor self-localization and Sound Source Localization (SSL) using a swarm of microphone-embedded-micro-quadrocopters (size10 cm). Micro-quadrocopters are extremely noisy, have low CPU power and cannot lift heavy equipment: the small payload of each micro-quadrocopter (5 g) only allows us to equip it with one microphone in addition to the inbuilt motion sensors. To perform robust SSL despite these issues, we propose three functions: (1) Self-localization of the quadrocopters using sound landmarks placed in the environment, and simultaneous localization of unknown sound sources; (2) Sound source detection; (3) Distributed data fusion based on noisy information from all members of the swarm. To achieve these, we propose three algorithms that are robust to noise, can perform with a varying number of quadrocopters, and do not rely on GPS nor motion capture to allow indoor operations: (1) A sound-based Unscented Kalman Filter (UKF) for self-localization of each quadrocopter; (2) A peak-based algorithm for sound source detection; (3) A distributed SSL algorithm for swarms with consensus-based integration using a new filter termed Unscented Kalman Consensus Filter (UKCF). We evaluated the proposed methods in real world and in simulated environments. The preliminary results show that the sound-based UKF represents an improvement of 37% on position estimation precision compared to basic dead reckoning approaches, even when the theoretical assumptions are violated; the distributed UKCF gives an improvement of 85% on SSL compared to a single-sensor approach in simulation. [ABSTRACT FROM PUBLISHER]

In this paper the problem of patrolling an environment with a dynamic team of robots is targeted. Lately, the interest of the research community has been focused in the development of patrol strategies; however there is a deficit of studies comparing such strategies, namely in terms of their performance and team scalability in different environments. For this reason, an evaluation of five representative patrol approaches is presented in this article. Aiming to analyze the performance, ability to scale and the behavior resulting from interactions between teammates, extensive realistic simulation using ROS together with Stage was conducted. The metric used to compare the performance is the average idleness of the topological environment (i.e. graph), that represents the area to patrol. The results presented help to identify which strategies enable enhanced team scalability and which are the most suitable approaches given any environment, supporting future research directions in the field. [ABSTRACT FROM PUBLISHER]

A system procedure is proposed for a multi-robot rescue system that performs real-time exploration over disaster areas. Real-time exploration means that every robot exploring the area always has a communication path to human operators standing by at a base station and that the communication path is configured by ad hoc wireless networking. Real-time exploration is essential in multi-robot systems for USAR (urban search and rescue) because operators must communicate with every robot to support the victim detection process and ad hoc networking is suitable to configure a communication path among obstacles. The proposed system procedure consists of the autonomous classification of robots into search and relay types and behavior algorithms for each class of robot. Search robots explore the areas and relay robots act as relay terminals between search robots and the base station. The rule of the classification and the behavior algorithm refer to the forwarding table of each robot constructed for ad hoc networking. The table construction is based on DSDV (destination-sequenced distance vector) routing that informs each robot of its topological position in the network and other essentials. Computer simulations are executed with a specific exploration strategy of search robots. The results show that a multi-robot rescue system can perform real-time exploration with the proposed system procedure and reduce exploration time in comparison with the case where the proposed scheme is not adopted. [ABSTRACT FROM PUBLISHER]