Stick-slip vibrations present at the bottom hole assembly (BHA) of a generic oilwell drillstring subject to dry friction are studied. Different nonlinear differential equations-based models of a drillstring are analyzed. The drillstring models presented are oriented to avoid simulation problems due to the discontinuities originated by the presence of dry friction. The influence of different dri...

This paper presents an approach to Cartesian controlled heavy machines. The system under investigation is a drill rig equipped with two drilling booms each actuated by eight hydraulic drives. To improve accuracy and efficiency in both possible operation modes, drilling and bolting, a Cartesian control system has been implemented, which takes advantage of using different subsets of the redundant...

This paper presents a modification to L1 adaptive control that allows for disturbances entering at the output and application of this control strategy to Managed Pressure Drilling with harmonic disturbances representing the heave motion of a floating drilling rig. By incorporating the disturbance at the output into the reference model, it is shown that the L1 adaptive control structure can be l...

The process of borehole drilling is a nonlinear and many dimensional process. During drilling it is possible occurrence of some complications (for example transition of drilling tool in layer with anomalous pressure). New method of identification of rock layers with anomalous pressure was proposed and tested on real plant data.

This study focuses on the robust control of stabilized platform of rotary steering drilling system. Firstly, the uncertain and nonlinear mathematical model of stabilized platform is given by considering the outside interference, drilling technology and geometrical parameter perturbation of the borehole on stabilized platform under work condition. Then, an adaptive neural network sliding mode co...

Here we present a method for high-precision drilling using an industrial robot with high-bandwidth force feedback, which is used for building up pressure to clamp-up an end-effector to the work-piece surface prior to drilling. The focus is to eliminate the sliding movement (skating) of the end-effector during the clamp-up of the end-effector to the work-piece surface, an undesired effect that i...