Patent ID: 6039193
Filing Date: 2000-03-21
Classification: B66C

Abstract:
A method for automatically controlling a cranes's rider block liftline and taglines, comprising the steps of:providing a crane having a base with a boom extending therefrom at a point of attachment to define a boom angle with a horizontal reference, said crane further being equipped with a rider block tagline system in which a rider block can be adjusted vertically by a liftline and horizontally by taglines;defining a coordinate system having an origin at said point of attachment;determining a current position of said rider block in terms of its horizontal coordinate and vertical coordinate relative to said origin, and in terms of an inhaul angle of said liftline;generating a matrix that defines i) incremental change in said horizontal coordinate with respect to incremental change in each of said boom angle, a length of said liftline and a length of said taglines, ii) incremental change in said vertical coordinate with respect to incremental change in each of said boom angle, said length of said liftline and said length of said taglines, and iii) incremental change in the sine of said inhaul angle with respect to incremental change in each of said boom angle, said length of said liftline and said length of said taglines;providing a vector defining velocity criteria for said rider block in terms of horizontal motion of said rider block, vertical motion of said rider block and rate of change of said inhaul angle;multiplying said vector by an inversion of said matrix to generate a control matrix that defines speed and direction of travel for said liftline and said taglines; andcontrolling movement of said liftline and said taglines using said control matrix.