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Kruijff, G.J.M.; Kruijff-Korbayová, I.; Keshavdas, S.; Larochelle, B.; Janíček, M.; Colas, F.; Liu, M.; Pomerleau, F.; Siegwart, R.; Neerincx, M.A.; Looije, R.; Smets, N.J.J.M; Mioch, T.; van Diggelen, J.; Pirri, F.; Gianni, M.; Ferri, F.; Menna, M.; Worst, R.; Linder, T.; Tretyakov, V.; Surmann, H.; Svoboda, T.; Reinštein, M.; Zimmermann, K.; Petříček, T.; Hlaváč, V.
doi: 10.1080/01691864.2014.976654pmid: N/A
Tipover may cause fatal damages to the mobile robot system during obstacle crossing or stair climbing, and the system centroid position (SCP) is very important for the tipover stability. By monitoring the SCP, it is possible to estimate the risk of tipover and take appropriate actions to prevent the incident from happening. This paper proposes a new tipover avoidance method for enhancing the tipover stability of a tracked mobile manipulator by online adjusting the SCP. The tipover stability criteria for the robot are discussed based on the orientation data from a three-axial gyroscope and the SCP calculation. The velocity kinematic model of the manipulator for SCP adjustment is also presented in this paper. In addition, a redundancy resolution method is employed in order to improve the performance of the robot. The proposed method is applied to a search and rescue robot consists of a four degree of freedom manipulator and a tracked mobile base, and the effectiveness of this method is demonstrated by experimental results.
Park, Jongwon; Kim, Kyung-Soo; Kim, Soohyun
doi: 10.1080/01691864.2014.968617pmid: N/A
This paper introduces a novel design for a robotic leg to achieve a fast running mechanism that is inspired by domestic cats. The skeletomuscular system and parallel leg movement of a cat are analyzed and applied to determine the link parameters and the linkage structure of the proposed mechanism. The linkage design of the leg mechanism is explained, and a kinematic analysis based on vector loop equations is performed. The effectiveness of the proposed mechanism is verified experimentally. A single leg clamped to a vertically moving slider exhibits a step frequency of 4.45 Hz while supporting a 0.5 kg body weight. The biped robot runs at an average speed of 0.75 m/s at a step frequency of 2.8 Hz for a trot gait on flat ground. This leg mechanism can facilitate the development of fast running robot systems.
Kamezaki, Mitsuhiro; Iwata, Hiroyasu; Sugano, Shigeki
doi: 10.1080/01691864.2014.959053pmid: N/A
A practical operator support system for disaster response work using construction machinery is applied to object-break operations using a dual-arm machine. An object-break operation, which separates an object into two different parts by applying massive pulling force, requires skillful force and trajectory controls. Operators typically have trouble visually perceiving the movement of the manipulator because the target object is strongly restrained. As a result, after the object has been separated into two pieces, the operator may continue performing lever operations because of unavoidable perception reaction time and the manipulator may collide with the surrounding environment. A control input cancellation system based on object-break identification is proposed to reduce the time difference between the object break and operation stoppage. A support system for disaster response situations must be safe and efficient and accommodate operators with various skill levels; thus, common physical phenomena related to the object breakage should be exploited. The system cancels control inputs to stop the movement of the manipulator when an object-break flag is detected, which is defined as a situation where the force applied to each joint of a manipulator decreases rapidly when a lever operation and load on the inside of the grapple are detected. Demolition experiments were conducted using a hydraulic dual-arm system. The results indicate that the displacement of the end-point after the object breaks is greatly decreased and the completion time of the task is reduced as well.
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doi: 10.1080/01691864.2014.985335pmid: N/A
This paper describes our experience in designing, developing and deploying systems for supporting human–robot teams during disaster response. It is based on R&D performed in the EU-funded project NIFTi. NIFTi aimed at building intelligent, collaborative robots that could work together with humans in exploring a disaster site, to make a situational assessment. To achieve this aim, NIFTi addressed key scientific design aspects in building up situation awareness in a human–robot team, developing systems using a user-centric methodology involving end users throughout the entire R&D cycle, and regularly deploying implemented systems under real-life circumstances for experimentation and testing. This has yielded substantial scientific advances in the state-of-the-art in robot mapping, robot autonomy for operating in harsh terrain, collaborative planning, and human–robot interaction. NIFTi deployed its system in actual disaster response activities in Northern Italy, in July 2012, aiding in structure damage assessment.