Sphere encapsulated oriented-discrete orientation polytopes (S-dop) collision culling for multi-, rigid body dynamic

This paper discusses on sphere encapsulated oriented-discrete orientation polytopes (therefore will be referred to as S-Dop) collision culling for multiple rigid body simulation. In order to improve performance of the whole simulation system, there are available options in sacrificing the accuracy over speed by using certain approximation techniques. The aim of this research is to achieve excellent performance through implementation of suitable culling technique, without jeopardizing the resulting behavior so that the simulation will still be physically plausible. The basic idea is to identify the highly probable pairs to collide and test the pair with a more accurate collision test in broad-phase collision detection, before the pair is passed to a more costly stage. Results from the experiments showed that there are a number of ways to implement the sphere encapsulated or-Dops (S-Dop) collision culling on a multiple rigid body simulation depending on the level of performance needed

High-Dimensional Design Evaluations For Self-Aligning Geometries

Physical connectors with self-aligning geometry aid in the docking process for many robotic and automatic control systems such as robotic self-reconfiguration and air-to-air refueling. This self-aligning geometry provides a wider range of acceptable error tolerance in relative pose between the two rigid objects, increasing successful docking chances. In a broader context, mechanical alignment properties are also useful for other cases such as foot placement and stability, grasping or manipulation. Previously, computational limitations and costly algorithms prevented high-dimensional analysis. The algorithms presented in this dissertation will show a reduced computational time and improved resolution for this kind of problem. This dissertation reviews multiple methods for evaluating modular robot connector geometries as a case study in determining alignment properties. Several metrics are introduced in terms of the robustness of the alignment to errors across the full dimensional range of possible offsets. Algorithms for quantifying error robustness will be introduced and compared in terms of accuracy, reliability, and computational cost. Connector robustness is then compared across multiple design parameters to find trends in alignment behavior. Methods developed and compared include direct simulation and contact space analysis algorithms (geometric by a \u27pre-partitioning\u27 method, and discrete by flooding). Experimental verification for certain subsets is also performed to confirm the results. By evaluating connectors using these algorithms we obtain concrete metric values. We then quantitatively compare their alignment capabilities in either SE(2) or SE(3) under a pseudo-static assumption

Semi-automation of a rockbreaker system: dynamic modeling and optimal collision-free trajectory planning

In light of technological advancements, the mining industry is seeing an increase in equipment automation. A hydraulic rockbreaker is a machine that would bene t from automation. The goal of this research is to develop some of the necessary algorithms to render a rockbreaker semi-autonomous. Semi-automation of such systems would allow for improved ease of use, increased productivity and e ciency of rock breaking operations, reduced maintenance costs while also removing the operator from harm's way. Several components are necessary to make semi-automation feasible, including a dynamic model as well as trajectory planning algorithms which generate collision-free trajectories to be used by a controller. The development of a complete dynamic model for such a system would allow for better control when using model-based controllers. However, such a model is di cult to develop in practice, has added complexity and may be computationally expensive. In this work, simpli ed dynamic models are developed and compared with respect to a complete dynamic model of the rockbreaker. One of the resulting simpli ed dynamic models, which only considers the inertial and gravitational e ects of the rockbreaker's mechanical links as well as the gravitational e ects of its hydraulic actuators, is shown to provide adequate representation of the system so as to be used in a model-based controller. The work also develops a set of o ine trajectory planning algorithms that generate time-optimal trajectories which ensure smooth motions and hydraulic valve actuation while satisfying the system's ow rate constraints. With the addition of a collision avoidance strategy and collision detection algorithm, the generated trajectories within the system's work environment can be expected to be collision-free.Master of Applied Science (MASc) in Natural Resources Engineerin

Safe human-robot interaction based on dynamic sphere-swept line bounding volumes

This paper presents a geometric representation for human operators and robotic manipulators, which cooperate in the development of flexible tasks. The main goal of this representation is the implementation of real-time proximity queries, which are used by safety strategies for avoiding dangerous collisions between humans and robotic manipulators. This representation is composed of a set of bounding volumes based on swept-sphere line primitives, which encapsulate their links more precisely than previous sphere-based models. The radius of each bounding volume does not only represent the size of the encapsulated link, but it also includes an estimation of its motion. The radii of these dynamic bounding volumes are obtained from an algorithm which computes the linear velocity of each link. This algorithm has been implemented for the development of a safety strategy in a real human–robot interaction task.This work is funded by the Spanish Ministry of Education and the Spanish Ministry of Science and Innovation through the projects DPI2005-06222 and DPI2008-02647 and the grant AP2005-1458

Compact union of disjoint boxes: An efficient decomposition model for binary volumes

This paper presents in detail the CompactUnion of Disjoint Boxes (CUDB), a decomposition modelfor binary volumes that has been recently but brieflyintroduced. This model is an improved version of aprevious model called Ordered Union of Disjoint Boxes(OUDB). We show here, several desirable features thatthis model has versus OUDB, such as less unitary basicelements (boxes) and thus, a better efficiency in someneighborhood operations. We present algorithms forconversion to and from other models, and for basiccomputations as area (2D) or volume (3D). We alsopresent an efficient algorithm for connected-componentlabeling (CCL) that does not follow the classical two-passstrategy. Finally we present an algorithm for collision (oradjacency) detection in static environments. We test theefficiency of CUDB versus existing models with severaldatasets.Peer ReviewedPostprint (published version

Modelling and simulation of a multi-fingered robotic hand for grasping tasks

This paper develops the kinematic, dynamic and contact models of a three-fingered robotic hand (BarrettHand) in order to obtain a complete description of the system which is required for manipulation tasks. These models do not only take into account the mechanical coupling and the breakaway mechanism of the under-actuated robotic hand but they also obtain the force transmission from the hand to objects, which are represented as triangle meshes. The developed models have been implemented on a software simulator based on the Easy Java Simulations platform. Several experiments have been performed in order to verify the accuracy of the proposed models with regard to the real physic system.This work is supported by the Spanish Ministries of Education, Science and Innovation through the research project DPI2008-02647 ('Intelligent Manipulation through Haptic Perception and Visual Servoing by Using an Articulated Structure situated over a Robotic Manipulator') and the grant AP2005-1458