The taxi function

<p>This paper investigates the lane keeping control and the lateral control of autonomous ground vehicles, robots or the like considering the road agency formation unit (RAFU) functions. A strategy based knowing the real position of several points of the trajectory is proposed to achieve the lateral control purpose and maintain the lane keeping errors within the prescribed performance boundaries. The RAFU functions are applied to achieve these goals. The stability of these functions, their applicability to approach any arbitrary trajectory and the easy control of the possible error made on the approximation are useful advantages in practice.</p>

METHOD FOR OVERCOMING THE DEAD ENDS DURING MOVEMENTS TO THE TARGET POINT ALONG AN ARBITRARY TRAJECTORY OF THE OUTPUT LINK CENTER

The article proposed a method for overcoming the dead ends that arising during movements of the android robot's hand in an organized space along the velocity vector. In a dead end situation, the algorithm cannot calculate next configuration, which will allow the center of output link to be shifted at a given speed and positioning accuracy to the next point of the trajectory. The proposed method is based on the calculation of the permissible positioning accuracy of the center of the output link in order to change the position of the arm configuration relative to the forbidden zones with deviations from the specified path. The positioning accuracy in this case will depend on the width of the corridor in which the center of the output link can move freely, as well as on the distance between the center of the output link and the boundaries of the corridor. An algorithm is proposed using this method and the implementation of a test example confirming the verification of the performance of this algorithm is presented. The developed algorithm for the synthesis of movement along an arbitrary trajectory of the center of the output link allows one to determine the reachability of target points with the use of an automated method at the virtual level in the presence of forbidden zones. In this case, the given geometrical dimensions of the forbidden zones and objects of manipulation are taken into account. This algorithm can be used in the development of intelligent control systems for autonomously functioning robots that move objects of manipulation without the participation of a human operator.

Individual Condensation Trails in Aircraft Trajectory Optimization

Contrails are one of the driving contributors to global warming, induced by aviation. The quantification of the impact of contrails on global warming is nontrivial and requires further in-depth investigation. In detail, condensation trails might even change the algebraic sign between a cooling and a warming effect in an order of magnitude, which is comparable to the impact of aviation-emitted carbon dioxides and nitrogen oxides. This implies the necessity to granularly consider the environmental impact of condensation trails in single-trajectory optimization tools. The intent of this study is the elaboration of all significant factors influencing on the net effect of single condensation trails. Possible simplifications will be proposed for a consideration in single-trajectory optimization tools. Finally, the effects of the most important impact factors, such as latitude, time of the year, and time of the day, wind shear, and atmospheric turbulence as well as their consideration in a multi-criteria trajectory optimization tool are exemplified. The results can be used for an arbitrary trajectory optimization tool with environmental optimization intents.

Transient-Inflow-Performance Modeling From Analytic Line-Source Solutions for Arbitrary-Trajectory Wells

Summary We present two easily computable, equally valid, semianalytic, single-phase, constant-rate solutions to the diffusivity equation for an arbitrarily oriented uniform-flux line source in a 3D, anisotropic, bounded system in Cartesian coordinates. With the addition of superposition, these become inflow solutions for wells of arbitrary trajectory. In addition, we produce analytic time derivatives for pressure-transient analyses (PTAs) of complex wells. If we extract solution components for 2D systems from the general solution, we can construct discrete complex-fracture-inflow and PTA capability for vertical, fully penetrating fractures, suitable for use as the basis solution in modeling complex phenomena, such as pressure-constrained production or development of fracture interference. For a 3D slanted well, the full characterization of dimensionless pressure over 10 decades of dimensionless time behavior can be produced in 1.5 seconds. With a fast-computing analytic solution for pressure anywhere in the system, we can also produce dense pressure maps at scalable resolution where any point could represent an observation well for convolution and enhanced interpretation. Likewise, the pressure derivative and the slope of the logarithmic temporal derivative of pressure can be mapped throughout to indicate local flow regime in a complex system. In particular, we compare and contrast the PTA signatures from symmetrical and asymmetrical horizontal, slanted, and diagonal line sources and examine when the behavior of a thin 3D reservoir collapses to the equivalent of a 2D fully penetrating fracture. Once the reservoir-thickness/length ratio reaches 1:100, all wells with the same projection onto the x–y plane are indistinguishable except for very early time, probably masked by wellbore/fracture-storage effects.