Efficient closed-form solution of the kinematics of a tunnel digging machine

摘要

In this work the kinematics of a large size tunnel digging machine is investigated. The closed-loop mechanismudis made by 13 links and 13 class 1 couplings, 7 of which are actuated. This kind of machines are commonly usedudto perform ground drilling for the placement of reinforcement elements during the construction of tunnels. Theuddirect kinematic solution is obtained using three methods: the first two are based on the numerical solution ofudthe closure equation written using the Denavit-Hartenberg method, while the third is based on the definition andudsolution in closed form of an equivalent spherical mechanism. The procedures have been tested and implementedudwith reference to a real commercial tunnel digging machine. The use of the proposed method for the closed–formudsolution of direct kinematics allows to obtain a major reduction of the computation time in comparison with theudstandard numerical solution of the closure equation.