Analysis of human physical vulnerability using static equilibrium techniques of a Hazard flood for the determination of unsafe areas in the city of Catacaos – Piura, Peru

Heavy rains and El Niño phenomenon are recurring natural phenomena at a national level. These can cause floods due to the overflowing of rivers, which, when close to cities, can cause both human and material losses. The district of Catacaos, located in the city of Piura, was the one with the highest number of injuries due to the flood caused by El Niño phenomenon in 2017. This phenomenon causes a large amounts of rainfalls due to the presence of abnormally warm waters along the northern coast of Peru [1]. It is for this reason that the need arose to carry out an analysis of the physical vulnerability due to instability of people through static equilibrium, in said district, in order to present maps of unsafe areas in the face of this phenomenon. In this investigation, flood hazard maps are generated simulating the one presented in 2017, using 2D hydraulic modeling. For the generation of vulnerability curves, the instability analysis is performed by moment and drag force. Finally, maps with unsafe areas are made using ArcGis software. Where the results obtained indicate that 29.37% of the city was flooded. Likewise, the vulnerability maps generated show us that women and men over 18 years of age in the city of Catacaos would be vulnerable to dragging and overturning in the face of floods in 16.54% and 13.21%, respectively, of the total studied area. This information will be useful for the development of future evacuation plans during floods, carried out by national entities.

On the kinematics of a concave sidecut line deformed on a flat surface

The present paper investigates the static equilibrium of a thin elastic structure with concave sidecut pressed against a flat rigid surface, as an idealization of a ski or snowboard undergoing the conditions of a carved turn. An analytical model is derived to represent the contact behaviour and provide an explanation for concentrated loads occurring at the sidecut extremities. The deformations are prescribed assuming tied contact along the sidecut line and neglecting torsional deformations. The loading conditions leading to this ideal deformed state are then sought, in order to better understand the mechanics of the turn. The results are illustrated with different sidecut geometries and compared with finite element computations for validation purposes. Depending on the function describing the sidecut line, concentrated force and moment are found to take place at the sidecut extremities.

Group interaction of robots with an arbitrary kinematic diagram of manipulators during synchronous execution of technological operations

The stabilization of the manipulated object near the position of static equilibrium under kinematic and force disturbances during cooperative transportation by two robots of arbitrary structure is considered. The dynamic balance of an object in grippers is described by the Mathieu equation. The controlled executive system of the coupled robot provides adjustment of the manipulation system with minimal potential energy in the grippers. A variant of the optimal control in terms of speed is considered when transferring the system to a position close to static equilibrium. Keywords: robot, group control, controlled generalized coordinates, continuity of connections, cooperative work. [email protected]

Intuitive Physical Human-Robot Interaction using an Underactuated Redundant Manipulator with Complete Spatial Rotational Capabilities

In this paper, the concept of underactuated redundancy is presented using a novel spatial two-degree-of-freedom (2-DoF) gravity balanced rotational manipulator, composed of movable counterweights. The proposed kinematic arrangement makes it possible to intuitively manipulate a payload undergoing 3-DoF spatial rotations by adding a third rotational axis oriented in the direction of gravity. The static equilibrium equations of the 2-DoF architecture are first described in order to provide the required configuration of the counterweights for a statically balanced mechanism. A method for calibrating the mechanism, which establishes the coefficients of the static equilibrium equations, is also presented. In order to both translate and rotate the payload during manipulation, the rotational manipulator is mounted on an existing translational manipulator. Experimental validations of both systems are presented to demonstrate the intuitive and responsive behaviour of the manipulators during physical human-robot interactions.

Predicting Crenulate Bay Profiles from Wave Fronts: Numerical Experiments and Empirical Formulae

For crenulate-shaped bays, the coastal outline assumes a specific shape related to the predominant waves in the area: it generally consists of a tangential zone downcoast and a curved portion upcoast. Many coastal engineers have attempted to derive an expression of the headland bay shapes that emerge when a full equilibrium is reached (stable or dynamic). However, even though models for static equilibrium bays exist, they are merely of an empirical kind, lacking further insight on relationships between incident wave characteristics and beach shape. In addition, it is commonly believed that shoreline profiles tend to follow wave fronts, but this has been never fully verified. In this paper, we investigate a possible correlation between static equilibrium profiles and wave front shapes. Numerical experiments have been performed using the MIKE 21 Boussinesq Wave module, and the generated wave fronts have been compared to the hyperbolic-tangent equilibrium profile. A thoughtful analysis of results revealed that a single-headland equilibrium profile is merely the wave front translated perpendicularly to the wave direction at the headland tip, without any influence of wave period or in wave direction. A new function called the “wave-front-bay-shape equation” has been obtained, and the application and validation of this formula to the case-study bay of the Bagnoli coast (south-west of Italy) is described in the paper.