Sketching piecewise clothoid curves

McCrae, James; Singh, Karan

doi:10.1016/j.cag.2009.05.006

Cited by 102 publications

(85 citation statements)

References 10 publications

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“…The point L i is connected to l 2 using clothoid curves [35][36] denoted by connect 2 (L i , l 2 ). The purpose of clothoids is to generate a curve that makes the vehicle correct its angle of orientation, change its lateral position in the road and generate a curve for the vehicle to traverse on a curved road.…”

Section: Curve Generationmentioning

confidence: 99%

Dynamic distributed lanes: motion planning for multiple autonomous vehicles

Kala

Warwick

2014

Appl Intell

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Unorganized traffic is a generalized form of travel wherein vehicles do not adhere to any predefined lanes and can travel in-between lanes. Such travel is visible in a number of countries e.g. India, wherein it enables a higher traffic bandwidth, more overtaking and more efficient travel. These advantages are visible when the vehicles vary considerably in size and speed, in the absence of which the predefined lanes are near-optimal. Motion planning for multiple autonomous vehicles in unorganized traffic deals with deciding on the manner in which every vehicle travels, ensuring no collision either with each other or with static obstacles. In this paper the notion of predefined lanes is generalized to model unorganized travel for the purpose of planning vehicles travel. A uniform cost search is used for finding the optimal motion strategy of a vehicle, amidst the known travel plans of the other vehicles. The aim is to maximize the separation between the vehicles and static obstacles. The search is responsible for defining an optimal lane distribution among vehicles in the planning scenario. Clothoid curves are used for maintaining a lane or changing lanes. Experiments are performed by simulation over a set of challenging scenarios with a complex grid of obstacles. Additionally behaviours of overtaking, waiting for a vehicle to cross and following another vehicle are exhibited.

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Section: Curve Generationmentioning

confidence: 99%

Dynamic distributed lanes: motion planning for multiple autonomous vehicles

Kala

Warwick

2014

Appl Intell

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“…They applied b-spline fitting methods on point sets and then converted them into piecewise monotonic curvature curves. McCrae and Singh [19], developed a sketching interface that converts individual strokes into piecewise clothoids for road design. They based their approach on a curvature analysis followed by a segmentation algorithm.…”

Section: Piecewise Clothoid Fittingmentioning

confidence: 99%

“…On the other extreme, having a large number of clothoid segments results in rapidly changing trend in the curvature profiles thus leading to visually less pleasing results. To be able to control this trade off with a user defined parameter, we adopted the curvature segmentation method proposed by McCrae and Singh [19].…”

Section: Curvature Segmentationmentioning

confidence: 99%

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Sketch-based aesthetic product form exploration from existing images using piecewise clothoid curves

Orbay

Yumer

Kara

2012

Journal of Visual Languages & Computing

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We present a new sketch-based product form exploration technique that works from images and sketches of existing products. At the heart of our approach, is a multi-stroke curve beautification method and a curve-based image deformation algorithm. The proposed approach converts groups of strokes into piecewise clothoid curves in order to produce visually pleasing shapes. The deformation diffusion algorithm then spatially distributes the user specified deformations through out the image to produce smooth transformations from the original image to the resulting image. We demonstrate the technique on a variety of images including photo-realistic images, real product images, and sketches.

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“…The curvature of discrete planar curves can be estimated considering the curvature at each point P i , with i being the point index as in Figure 2.5 and using the circum-circle form with two adjacent points of the curve (MULLINEUX; ROBINSON, 2007 apud MCCRAE;SINGH, 2009). Then,…”

Section: Computing the Discrete Curvaturementioning

confidence: 99%

Piecewise linear continuous-curvature path planning for autonomous vehicles

Silva¹

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2018Trata-se da versão corrigida da dissertação. A versão original se encontra disponível na EESC/USP que aloja o Programa de Pós-Graduação de Engenharia Elétrica. Autonomous vehicles have increasingly become an attractive field due its promising capabilities of improvements regarding safety, comfort, traffic flow etc. A required attribute for those vehicles is the ability of autonomously compute its path towards a destination point. The path must be planned considering the constructive aspects of the vehicle in order to guarantee the maneuver feasibility. This work consists on computing a feasible path for autonomous vehicles with non-holonomic constraints. Piecewise linear continuouscurvature paths constituted of clothoids, circular arcs, and straight lines are used for this purpose, providing passenger's comfort. The road network is modeled from GPS (Global Positioning System) vehicle trajectories by defining lanes, roundabouts and intersections. GPS points are used later to parameterize lanes using clothoids and to extract roundabout centers and radii. This approach provides a sparse road network model since GPS points are replaced by parameterized curves. The information about connections between roads coming from the model is used by a global path planner, which computes a minimal length route from the vehicle current position to the destination point. After that, path planners compute intersection and roundabout paths depending on the nature of connections between roads. Also, lanes changes are performed to obey traffic rules. These three path planners that connects adjacent roads use clothoids, circular arc, and straight lines as interpolating curves whose curvature is constrained to that the vehicle can perform: the intersection path planner uses only a minimal amount of steering to perform the maneuver, increasing the comfort level; the roundabout path planner takes the roundabout center and radius as well as parameters that defines the entrance and exit maneuvers to compute the path; the lane change path planner connects lanes belonging to the same road with a prescribed longitudinal traveled distance depending on whether this maneuver is required. In the end, an global continuous-curvature path is generated. As the result of this work, a real urban scenario is modeled and the proposed approaches are validated. Veículos autônomos têm cada vez mais se tornado um campo atraente de pesquisa devido às suas capacidades promissoras de melhorias em segurança, conforto, fluxo de tráfego, etc. Um atributo necessário para esses veículos é a capacidade de calcular, de forma autônoma, o seu caminho para um ponto de destino. O percurso deve ser planejado considerando os aspectos construtivos do veículo para que a viabilidade das manobras a serem executadas seja garantida. Este trabalho consiste no planejamento de trajetória para veículos autônomos com restrições não-holonômicas. Utilizam-se, para esse efeito, trajetórias cuja curvatura seja contínua e linear por partes, constituídas por clotóides, arcos de circun...

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Sketching piecewise clothoid curves

Cited by 102 publications

References 10 publications

Dynamic distributed lanes: motion planning for multiple autonomous vehicles

Dynamic distributed lanes: motion planning for multiple autonomous vehicles

Sketch-based aesthetic product form exploration from existing images using piecewise clothoid curves

Piecewise linear continuous-curvature path planning for autonomous vehicles

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