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In the present work, a new method for the determination of the outrigger loads in mobile cranes is proposed. The approach adopted assumes the mobile crane as a rigid body and the ground having a linear elastic behavior. The outrigger reactions are determined, using the concept of complete support pattern, through the calculation of the area of triangles constructed within it. The main feature of the method is that the determination of the outrigger reactions can be done by means of graphical considerations with the advantage to perform the task quickly and without the use of complicated calculations. The knowledge of the outrigger pattern, the resultant of all the forces applied and the center of mass of the system crane-payload are only needed as input data. Although the method is suitable for cranes with an outrigger system of any number and shape, the simplification deriving from the use of the graphical approach is fully available only for an outrigger system with four outriggers having a specific shape. These configurations, however, represent the most common configuration found in real applications. The validity of the method proposed has been proven comparing the results with data available in the cranes' manuals and with actual reactions of the outriggers of a mobile cranes operating on site. [ABSTRACT FROM AUTHOR]

It is shown in this study the graphical analysis using velocity polygons may be used to locate direct singular positions of a limited degree-of-freedom (DOF) parallel manipulator. The three DOF parallel manipulator MIPS is treated for illustration. The conditions for the moving platform to become movable under zero driving speeds can be obtained using the graphical velocity analysis. Manipulator configurations satisfying these conditions are direct singular positions. Several direct singular positions are determined using this technique. In order to verify these singular positions, Jacobian matrix for this manipulator is also derived in this study, and singular positions determined from graphical analysis can make the Jacobian matrix singular. [ABSTRACT FROM AUTHOR]