Theory and practice of reversing control on multiply-articulated vehicles

A path-tracking controller is presented for automating the reversing of multiply-articulated vehicles. This uses a state feedback approach and steers the wheels of the front axle to ensure that the rearmost vehicle unit tracks a specified path. Linear closed-loop analysis is performed and shows that the controller is stable for vehicles with up to six trailers. The controller is implemented on three full-size experimental heavy vehicles: a ‘tractor–semitrailer’, a ‘B-double’ vehicle and a ‘B-triple’ vehicle, which have one trailer, two trailers and three trailers respectively. Experimental results are presented and the controller performance is evaluated. All test vehicles were able to track the paths to within 400 mm of the desired path. This research was funded by the Engineering and Physical Sciences Research Council (EPSRC) and Volvo Trucks through an Industrial CASE award. The authors would like to acknowledge Leo Laine and Carl-Johan Hoel from Volvo Trucks for their collaboration and contributions to the research.This is the author accepted manuscript. The final version is available from Sage via http://dx.doi.org/10.1177/095440701559691

A path planning and path-following control framework for a general 2-trailer with a car-like tractor

Maneuvering a general 2-trailer with a car-like tractor in backward motion is a task that requires significant skill to master and is unarguably one of the most complicated tasks a truck driver has to perform. This paper presents a path planning and path-following control solution that can be used to automatically plan and execute difficult parking and obstacle avoidance maneuvers by combining backward and forward motion. A lattice-based path planning framework is developed in order to generate kinematically feasible and collision-free paths and a path-following controller is designed to stabilize the lateral and angular path-following error states during path execution. To estimate the vehicle state needed for control, a nonlinear observer is developed which only utilizes information from sensors that are mounted on the car-like tractor, making the system independent of additional trailer sensors. The proposed path planning and path-following control framework is implemented on a full-scale test vehicle and results from simulations and real-world experiments are presented.Comment: Preprin

Implementation of Reversing Control on a Doubly Articulated Vehicle

The problem of reversing vehicles with two trailers could be solved with a semi-autonomous assistance system for automatically steering the vehicle. In the literature found, no controllers have been implemented on a full-size vehicle with two trailers. In this paper, two simple path-tracking controllers are presented for automating the reversing of a “B-double” vehicle, consisting of a tractor and two trailers. One of the controllers is a heuristic “preview point” controller; the other uses a state feedback approach. The controllers steer the wheels on the front axle so as to stabilize the vehicle in reverse and control the path of the rearmost axle to follow a prescribed path. A tuning strategy is outlined where both controllers are tuned using the linear quadratic regulator and have the same closed-loop poles. The two controllers are implemented on a full-size B-double test vehicle. Experimental results are discussed, and the controller performances are evaluated against criteria. With the state feedback controller, the test vehicle was able to track target paths, consisting of a roundabout and a lane change, to within 50 mm.This research was funded by the Engineering and Physical Sciences Research Council (EPSRC) and Volvo Trucks through an Industrial CASE award. The authors would like to acknowledge Leo Laine and Carl-Johan Hoel from Volvo Trucks for their collaboration and contributions to the research. The authors would like to acknowledge Denby Transport for their loan of the ‘Extra’ Eco-Link B-trailer for use in vehicle testing. The authors would like to acknowledge the members of the CVDC who supported the work in this paper. At the time of writing, the Consortium consisted of the University of Cambridge with the following partners from the heavy vehicle industry: Anthony Best Dynamics, Camcon, Denby Transport, Firestone Air Springs, GOODYEAR DUNLOP, Haldex, Motor Industry Implementation of Reversing Control on a Doubly-Articulated Vehicle 15 Research Association, SDC Trailers, SIMPACK, Tinsley Bridge, Tridec, Volvo Trucks, and Wincanton

Evaluation of navigability in skid-steer mobile robots with passive trailers moving on sloping terrain

[EN] The use of trailers allows robots to increase their load capacity to perform multiple tasks, but their use carries multiple risks. In this research, three metrics are developed to assess the navigability of robots with coupled trailers when moving at low speeds on inclined surfaces: an index that predicts the initiation of rollover in the robot or trailers; another index that estimates the start of the total slip due to the slopes of the terrain, either in the robot or the trailers; and finally, an index that quantifies the robot's ability to address itself and follow a path. These three metrics were developed based on the reaction forces of the wheels with the ground and were validated through  simulation and experimental tests using a Skid Steer robot called Lázaro, demonstrating their effectiveness in estimating the risk condition for which they were designed.[ES] El uso de remolques permite a los robots aumentar su capacidad de carga para realizar múltiples tareas, pero su uso conlleva múltiples riesgos. En esta investigación, se desarrollan tres métricas para evaluar la navegabilidad de robots con remolques acoplados cuando se mueven a bajas velocidades sobre superficies inclinadas: un í­ndice que predice el inicio del vuelco en el robot o los remolques; otro í­ndice que estima el inicio del deslizamiento total debido a las inclinaciones del terreno, ya sea en el robot o los remolques; y finalmente, un í­ndice que cuantifica la capacidad del robot para direccionarse y seguir una trayectoria. Estas tres métricas fueron desarrolladas con base en las fuerzas de reacción de las ruedas con el suelo y fueron validados a través de simulación y pruebas experimentales utilizando un robot Skid Steer llamado Lázaro, demostrándose su efectividad al estimar la condición de riesgo para la cual fueron diseñados.Este trabajo ha sido realizado parcialmente gracias al apoyo del Decanato de Investigación de la Universidad Nacional Experimental del Táchira bajo los proyectos No. 01-025-2016 y 01-004-2019.García, JM.; Yánez, P.; Martínez, JE. (2022). Evaluación de la navegabilidad en robots móviles skid-steer con remolques pasivos moviéndose sobre terrenos inclinados. Revista Iberoamericana de Automática e Informática industrial. 20(1):13-24. https://doi.org/10.4995/riai.2022.17161132420

Comparison of the vocabularies of the Gregg shorthand dictionary and Horn-Peterson's basic vocabulary of business letters

This study is a comparative analysis of the vocabularies of Horn and Peterson's The Basic Vocabulary of Business Letters1 and the Gregg Shorthand Dictionary.2 Both books purport to present a list of words most frequently encountered by stenographers and students of shorthand. The, Basic Vocabulary of Business Letters, published "in answer to repeated requests for data on the words appearing most frequently in business letters,"3 is a frequency list specific to business writing. Although the book carries the copyright date of 1943, the vocabulary was compiled much earlier. The listings constitute a part of the data used in the preparation of the 10,000 words making up the ranked frequency list compiled by Ernest Horn and staff and published in 1926 under the title of A Basic Writing Vocabulary: 10,000 Words Lost Commonly Used in Writing. The introduction to that publication gives credit to Miss Cora Crowder for the contribution of her Master's study at the University of Minnesota concerning words found in business writing. With additional data from supplementary sources, the complete listing represents twenty-six classes of business, as follows 1. Miscellaneous 2. Florists 3. Automobile manufacturers and sales companie