Dynamic Multi-Rigid-Body Systems with Concurrent Distributed Contacts: Theory and Examples

Trinkle, Jeff; Tzitzouris, James A.; Pang, Jong-Shi

doi:10.2172/780283

Cited by 18 publications

(30 citation statements)

References 15 publications

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“…Images are not the only sensory source: tactile and force sensor data and more is also important. Although some have explored low-level contact models (e.g., Trinkle et al 2001;Kolev and Todorov 2015, and others), these are too detailed for the level of abstraction where active perception operates.…”

Section: Why Has the Robotics Community Failed To Produce A Flexible mentioning

confidence: 99%

Revisiting active perception

2017

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Despite the recent successes in robotics, artificial intelligence and computer vision, a complete artificial agent necessarily must include active perception. A multitude of ideas and methods for how to accomplish this have already appeared in the past, their broader utility perhaps impeded by insufficient computational power or costly hardware. The history of these ideas, perhaps selective due to our perspectives, is presented with the goal of organizing the past literature and highlighting the seminal contributions. We argue that those contributions are as relevant today as they were decades ago and, with the state of modern computational tools, are poised to find new life in the robotic perception systems of the next decade.

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Section: Why Has the Robotics Community Failed To Produce A Flexible mentioning

confidence: 99%

Revisiting active perception

2017

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“…Various sources, even as early as in the late 1800s [69] Trinkle [70], and Trinkle et al [86]. Baraff describes a method that allows impulsive forces according to the principle of constraints when forces alone cannot solve contact [8].…”

Section: Methodsmentioning

confidence: 99%

Optimization-based animation

Milenkovic

Schmidl

2001

Proceedings of the 28th Annual Conference on Computer Graphics and Interactive Techniques

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of a doctoral dissertation at the University of Miami.Dissertation supervised by Professor Victor J. Milenkovic. No. of pages in text: 162A new paradigm for rigid body simulation is presented and analyzed. Current techniques for rigid body simulation run slowly on scenes with many bodies in close proximity. Each time two bodies collide or make or break a static contact, the simulator must interrupt the numerical integration of velocities and accelerations. Even for simple scenes, the number of discontinuities per frame time can rise to the millions. An efficient optimization-based animation (OBA) algorithm is presented which can simulate scenes with many convex threedimensional bodies settling into stacks and other "crowded" arrangements. This algorithm simulates Newtonian (second order) physics and Coulomb friction, and it uses quadratic programming (QP) to calculate new positions, momenta, and accelerations strictly at frame times. The extremely small integration steps inherent to traditional simulation techniques are avoided.Contact points are synchronized at the end of each frame. Resolving contacts with friction is known to be a difficult problem. Analytic force calculation can have ambiguous or non-existing solutions. Purely impulsive techniques avoid these ambiguous cases, but still require an excessive and computationally expensive number of updates in the case of many simultaneous contacts. It is shown informally that even taking into account advances in stiff integration techniques, penalty force methods cannot overcome this issue of running time in highly crowded scenes. New algorithms are presented that calculate simultaneous impulses to resolve collisions and static contacts under the Coulomb friction model. The simultaneous impulses are the solution to a QP.In addition, the algorithms apply "bouncing at distance" and "freezing of bodies" to further speed up the simulation. These new QP algorithms are hybridized with a traditional priority queue momentum update scheme to allow sequential impulses when they are required for realism, such as in the office toy pendulum. When added to the implementation of OBA, these new algorithms increase the speed of the simulation by a factor of up to 30.The position update has been hybridized with retroactive detection (RD) to prevent fast and thin bodies from passing through each other. Due to the modular design of the OBA simulator, the described techniques can be used as components in any existing simulator that follows a modular design of position update, finding contacts, and resolving contacts. Non-convex bodies are simulated as unions of convex bodies. Links and joints are simulated with bi-directional constraints. Analysis of the algorithm and discussion of example simulations are provided. DedicationIn loving memory of my father.iii

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“…These include impulse-based dynamics [17], penalty-based methods, and constraint-based dynamics; e.g. Gauss' principle of least constraints [20] or the linear complementarity problem (LCP) formulation [1], [25]. Poststabilization techniques for rigid body simulation with contact and constraints have also been proposed [4].…”

Section: B Collision Detection and Responsementioning

confidence: 99%

Adaptive Dynamics with Efficient Contact Handling for Articulated Robots

Gayle¹,

Manocha²

2006

Robotics: Science and Systems II

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Abstract-We present a novel adaptive dynamics algorithm with efficient contact handling for articulated robots. Our algorithm automatically computes a fraction of the joints whose motion provides a good approximation to overall robot dynamics. We extend Featherstone's Divide-and-Conquer algorithm and are able to efficiently handle all contacts and collisions with the obstacles in the environment. Overall, our approach provides a time-critical collision detection and resolution algorithm for highly articulated bodies and its complexity is sub-linear in the number of degrees-of-freedom. We demonstrate our algorithm on several complex articulated robots consisting of hundreds of joints.

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Dynamic Multi-Rigid-Body Systems with Concurrent Distributed Contacts: Theory and Examples

Cited by 18 publications

References 15 publications

Revisiting active perception

Revisiting active perception

Optimization-based animation

Adaptive Dynamics with Efficient Contact Handling for Articulated Robots

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