30 research outputs found

    Unmanned Ground and Aerial Robots Supporting Mine Action Activities

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    During the Humanitarianā€demining actions, teleoperation of sensors or multiā€sensor heads can enhance-detection process by allowing more precise scanning, which is useful for the optimization of the signal processing algorithms. This chapter summarizes the technologies and experiences developed during 16 years through national and/or Europeanā€funded projects, illustrated by some contributions of our own laboratory, located at the Royal Military Academy of Brussels, focusing on the detection of unexploded devices and the implementation of mobile robotics systems on minefields

    Prof. Cezar Oprișan (1955 ā€“ 2018)

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    Professor Cezar Oprișan was born on April 27th, 1955, in Tupilați, Neamț District, Romania. He graduated from the Mechanical Engineering Faculty, Polytechnic Institute "Gheorghe Asachi" of Iasi, Machines Building Technology specialization (1975-1980). After three years of activity in industry, as technology engineer with Pipe Company in Roman, Romania, he started his academic career as assistent professor in the Department of Machine Design and Mechanisms (today, Mechanical Engineering, Mechatronics and Robotics Department), Mechanical Engineering Faculty, "Gheorghe Asachi" Technical University of Iasi

    The Kinematics of a Bipod R2RR Coupling between Two Non-Coplanar Shafts

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    The paper presents a new solution for motion transmission between two shafts with non-intersecting axes. The structural considerations fundament the existence in the structure of the mechanism of three revolute pairs and a bipod contact. Compared to classical solutions, where linkages with cylindrical pairs are used, our solution proposes a kinematical chain also containing higher pairs. Due to the presence of a higher pair, the transmission is much simpler, the number of elements decreases, and as a consequence, the kinematical study is straightforward. Regardless, the classical analysis of linkages cannot be applied because of the presence of the higher pair. For the proposed spatial coupling, the transmission ratio is expressed as a function of constructive parameters. The positional analysis of the mechanism cannot be performed using the Hartenbergā€“Denavit method due to the presence of a bipod contact, and instead, the geometrical conditions of existence for the bipod contact are applied. The Hartenbergā€“Denavit method requires the replacement of the bipodic coupling with a kinematic linkage with cylindrical (revolute and prismatic) pairs, resulting in complicated analytical calculus. To avoid this aspect, the geometrical conditions required by the bipod coupling were expressed in vector form, and thus, the calculus is significantly reduced. The kinematical solution for the proposed transmission can be obtained in two ways: first, by considering the equivalent transmission containing only cylindrical pairs and applying the classical analysis methods; second, by directly expressing the condition of definition for the higher pairs (bipodic pair) in vector form. The last method arrives at a simpler solution for which analytical relations for the positional parameters are obtained, with one exception where numerical calculus is needed (but the precision of this parameter is controlled). The analytical kinematics results show two possibilities of building the actual mechanism with the same constructive parameters. The rotation motions from the revolute pairs, internal and driven, and the motions from the bipod joint were obtained through numerical methods since the equations are very intricate and cannot be solved analytically. The excellent agreement validates the theoretical solutions obtained and the possibility of applying such mechanisms in technical applications. The constructive solution exemplified here is simple and robust

    The Kinematics of a Bipod R2RR Coupling between Two Non-Coplanar Shafts

    No full text
    The paper presents a new solution for motion transmission between two shafts with non-intersecting axes. The structural considerations fundament the existence in the structure of the mechanism of three revolute pairs and a bipod contact. Compared to classical solutions, where linkages with cylindrical pairs are used, our solution proposes a kinematical chain also containing higher pairs. Due to the presence of a higher pair, the transmission is much simpler, the number of elements decreases, and as a consequence, the kinematical study is straightforward. Regardless, the classical analysis of linkages cannot be applied because of the presence of the higher pair. For the proposed spatial coupling, the transmission ratio is expressed as a function of constructive parameters. The positional analysis of the mechanism cannot be performed using the Hartenberg–Denavit method due to the presence of a bipod contact, and instead, the geometrical conditions of existence for the bipod contact are applied. The Hartenberg–Denavit method requires the replacement of the bipodic coupling with a kinematic linkage with cylindrical (revolute and prismatic) pairs, resulting in complicated analytical calculus. To avoid this aspect, the geometrical conditions required by the bipod coupling were expressed in vector form, and thus, the calculus is significantly reduced. The kinematical solution for the proposed transmission can be obtained in two ways: first, by considering the equivalent transmission containing only cylindrical pairs and applying the classical analysis methods; second, by directly expressing the condition of definition for the higher pairs (bipodic pair) in vector form. The last method arrives at a simpler solution for which analytical relations for the positional parameters are obtained, with one exception where numerical calculus is needed (but the precision of this parameter is controlled). The analytical kinematics results show two possibilities of building the actual mechanism with the same constructive parameters. The rotation motions from the revolute pairs, internal and driven, and the motions from the bipod joint were obtained through numerical methods since the equations are very intricate and cannot be solved analytically. The excellent agreement validates the theoretical solutions obtained and the possibility of applying such mechanisms in technical applications. The constructive solution exemplified here is simple and robust

    Chapter Unmanned Ground and Aerial Robots Supporting Mine Action Activities

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    Lightweight protective structures and materials such as the personal protective equipment (PPE) for explosive ordnance disposal (EOD) personnel are frequently under investigation globally. Their mechanical response to impulsive loads such as blast and ballistic impacts is critical for establishing the spectrum of their performance against various types of threats. This chapter presents a novel testing technique that incorporates three near-simultaneous impacts in one shot in order to acquire deeper understanding of the dynamic interactions that take place during an explosion. A numerical model of an aramid fabric is developed to examine the parameters that influence the ballistic performance under multiple impacts. Fragment cluster impacts with dense dispersion have increased probability to perforate the target material. Heterogeneous, non-isotropic materials, like most of the ballistic grade protective materials, distribute the energy of the impacts in the form of stress wave streams causing the material to behave differently depending on the formation of the impacting fragments. Experimental work with aramid fabrics against single and triple impacts with the fragment-simulating projectile (FSP, 1.102 g) indicates that the ballistic limit in triple impacts is considerably lower that the ballistic limit in single impacts. The actual ballistic performance against multiple fragment impacts is severely underestimated with the classical single-impact methodologies
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