External Force Field Modeling for Autonomous Surface Vehicles

Abstract

Operating in the presence of strong adverse forces is a particularly challenging problem in field robotics. In most robotic operations where the robot is not firmly grounded, such as aerial, surface, and underwater, minimal external forces are assumed as the standard operating procedures. The first action for operating in the presence of non-trivial forces is modeling the forces and their effect on the robots motion. In this work an Autonomous Surface Vehicle (ASV), operating on lakes and rivers with varying winds and currents, collects wind and current measurements with an inexpensive custom-made sensor suite setup, and generates a model of the force field. The modeling process takes into account depth, wind, and current measurements along with the ASVs trajectory from GPS. In this work, we propose a method for an ASV to build an environmental force map by integrating in a Gaussian Process the wind, depth, and current measurements gathered at the surface. We run extensive experimental field trials for our approach on real Jetyak ASVs. Experimental results from different locations validate the proposed modeling approach.

Dynamic Autonomous Surface Vehicle Control and Applications in Environmental Monitoring

“…Even though these works, addressing collection and modeling of dynamic environmental properties, they do not provide the time and space considerations that impact a lightweight, small-scale ASV. To implement a future adaptive controls and online path planning techniques for surface vehicles a reliable map of environmental forces is required and in this work we generate those with Gaussian Processes [12].…”

“…a) Modelling Environmental Forces: When performing waypoint navigation it is sometimes desirable to perform corrections beforehand rather that reactively by current measurements of sensors. Collecting wind and water current data, we build a map of the external forces speed and direction using Gaussian Processes with Matern 3/2 kernel [12] (see Figure 4). b) Prediction of the Force Affect: For reactive response the direct measurements are taken from the sensors.…”

Diseño de un autopiloto para pequeños vehículos no tripulados

“…Esto hace que hoy día diversos grupos de investigación alrededor del mundo estén trabajando con este tipo de vehículos. Por ejemplo, en [1]- [4] se han desarrollado pequeños ASV con fines de investigación. Estos vehículos han demostrado ser de gran utilidad en tareas tales como el monitoreo medioambiental, la toma de muestras, la confección de mapas batimétricos entre otros, todos ellos sin el costo de desplegar grandes vehículos y personal.…”

“…Sin embargo, aún es la autonomía un factor limitante para ciertos escenarios en donde se deben efectuar misiones prolongadas. En estos escenarios la propulsión eléctrica no es una alternativa viable y se hace necesario recurrir a vehículos propulsados por combustible, los cuales suelen ser de mayor tamaño y costo, con una mecánica más compleja y la necesidad de un3 Microelectromechanical systems 4. Global Navigation Satellite Systems.Recibido: 07/12/18; Aceptado: 18/02/19…”

Meander Based River Coverage by an Autonomous Surface Vehicle

“…Due to these curves, the water flow at different speeds across the river, which in turns contributes to different rates of erosion and sediment deposits. ASV operations are heavily affected by the water currents encountered [15], as such, the efficiency of the ASV's navigation can be improved by choosing to go against the slower currents and with the faster currents.…”