Recursive forward dynamics for multiple robot arms moving a common task object

Recursive forward dynamics algorithms are developed for an arbitrary number of robot arms moving a commonly held object. The multiarm forward dynamics problem is to find the angular accelerations at the joints and the contact forces that the arms impart to the task object. The problem also involves finding the acceleration of this object. The multiarm forward dynamics solutions provide a thorough physical and mathematical understanding of the way several arms behave in response to a set of applied joint moments. Such an understanding simplifies and guides the subsequent control design and experimentation process. The forward dynamics algorithms also provide the necessary analytical foundation for conducting analysis and simulation studies. The multiarm algorithms are based on the filtering and smoothing approach recently advanced for single-arm dynamics, and they can be built up modularly from the single-arm algorithms. The algorithms compute recursively the joint-angle accelerations, the contact forces, and the task-object accelerations. Algorithms are also developed to evaluate in closed form the linear transformations from the active joint moments to the joint-angle accelerations, to the task-object accelerations., and to the task-object contact forces. A possible computing architecture is presented as a precursor to a more complete investigation of the computational performance of the dynamics algorithms

A spatial operator algebra for manipulator modeling and control

A recently developed spatial operator algebra, useful for modeling, control, and trajectory design of manipulators is discussed. The elements of this algebra are linear operators whose domain and range spaces consist of forces, moments, velocities, and accelerations. The effect of these operators is equivalent to a spatial recursion along the span of a manipulator. Inversion of operators can be efficiently obtained via techniques of recursive filtering and smoothing. The operator algebra provides a high level framework for describing the dynamic and kinematic behavior of a manipulator and control and trajectory design algorithms. The interpretation of expressions within the algebraic framework leads to enhanced conceptual and physical understanding of manipulator dynamics and kinematics. Furthermore, implementable recursive algorithms can be immediately derived from the abstract operator expressions by inspection. Thus, the transition from an abstract problem formulation and solution to the detailed mechanizaton of specific algorithms is greatly simplified. The analytical formulation of the operator algebra, as well as its implementation in the Ada programming language are discussed

Classification using set-valued Kalman filtering and Levi\u27s decision theory

We consider the problem of using Levi\u27s expected epistemic decision theory for classification when the hypotheses are of different informational values, conditioned on convex sets obtained from a set-valued Kalman filter. The background of epistemic utility decision theory with convex probabilities is outlined and a brief introduction to set-valued estimation is given. The decision theory is applied to a classifier in a multiple-target tracking scenario. A new probability density, appropriate for classification using the ratio of intensities, is introduced

Parallel O(log n) algorithms for open- and closed-chain rigid multibody systems based on a new mass matrix factorization technique

In this paper, parallel O(log n) algorithms for computation of rigid multibody dynamics are developed. These parallel algorithms are derived by parallelization of new O(n) algorithms for the problem. The underlying feature of these O(n) algorithms is a drastically different strategy for decomposition of interbody force which leads to a new factorization of the mass matrix (M). Specifically, it is shown that a factorization of the inverse of the mass matrix in the form of the Schur Complement is derived as M(exp -1) = C - B(exp *)A(exp -1)B, wherein matrices C, A, and B are block tridiagonal matrices. The new O(n) algorithm is then derived as a recursive implementation of this factorization of M(exp -1). For the closed-chain systems, similar factorizations and O(n) algorithms for computation of Operational Space Mass Matrix lambda and its inverse lambda(exp -1) are also derived. It is shown that these O(n) algorithms are strictly parallel, that is, they are less efficient than other algorithms for serial computation of the problem. But, to our knowledge, they are the only known algorithms that can be parallelized and that lead to both time- and processor-optimal parallel algorithms for the problem, i.e., parallel O(log n) algorithms with O(n) processors. The developed parallel algorithms, in addition to their theoretical significance, are also practical from an implementation point of view due to their simple architectural requirements

Publications of the Jet Propulsion Laboratory, 1988

This bibliography describes and indexes by primary author the externally distributed technical reporting, released during calendar year 1988, that resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Laboratory. Three classes of publications are included: JPL publications in which the information is complete for a specific accomplishment; articles from the quarterly Telecommunications and Data Acquisition (TDA) Progress Report; and articles published in the open literature

High level language-based robotic control system

This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages

Dynamical Analysis Of A Passive Dynamic Walking Biped Robot

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012Bu tezde, Uzaysal Operatör Cebri (UOC) kullanılarak pasif dinamik yürüme yapan bir robotun dinamik incelemesi yapılmıştır. Bu yöntem robotik bir sistemin eklem ve bağlantı elemanlarındaki kuvvet ve hız dağılımlarını vermekle birlikte, özyinemeli yapısı sayesinde hızlı hesaplama yapmaya olanak sağlamaktadır. Bir diğer yandan pasif dinamik yürüme ise, genellikle iki bacaklı olarak seçilen bir sistemin eğik bir düzlemde sadece yerçekimi kuvveti etksininde yürüme hareketini gerçekleştirdiği durumdur. İki bacaklı sistem yerçekimi etkisi altında tam bir yürüme hareketini tekrarlar. Bu fikir genellikle iki bacaklı robotların verimlerinin arttırılmasında kullanılmaktadır. Tezde tasarlanan beş serbestlik dereceli iki bacaklı sistem iki boyutlu uzayda tanımlanmıştır. İnsan bacağının doğası gereği sistem diz ve diz kitleme mekanizmaları ile modellenmiş ve bu mekanizmalar sözde eklem yöntemi yardımıyla oluşturulmuştur. Dizlerdeki ve ayaklardaki sınır kuvvetlerinin hesaplanması da bu çalışma dahilinde incelenmiştir. Sonuçlar pasif dinamik yürüme yapan bir robotun iç dinamiklerini göz önüne sermektedir.In this thesis using the Spatial Operator Algebra (SOA) the dynamic analysis of a passive dynamic walking biped robot is obtained. This method reveals the force and velocity distributions of links and joints of a robotic system, and also computationally efficient because of its recursive manner. On the other hand, passive dynamic walking is a case, where a mechanism, mostly biped, walks only by the gravitational forces on a shallow slope ground. Two legged system repeats full walking cycle under the influence of the gravitational force. This idea is mostly being used for efficiency problem of bipeds. In this thesis, a 5 degree of freedom biped robot is designed in 2D space. Due to the nature of human legs, the biped is modeled with knees and knee locking system using pseudo joint technique. The constraint forces due to the boundary conditions on knees and feet have also been computed as a result of this thesis. The results provided a deep insight of a passive dynamic walking biped robot.Yüksek LisansM.Sc

Proceedings of the Fifth NASA/NSF/DOD Workshop on Aerospace Computational Control

The Fifth Annual Workshop on Aerospace Computational Control was one in a series of workshops sponsored by NASA, NSF, and the DOD. The purpose of these workshops is to address computational issues in the analysis, design, and testing of flexible multibody control systems for aerospace applications. The intention in holding these workshops is to bring together users, researchers, and developers of computational tools in aerospace systems (spacecraft, space robotics, aerospace transportation vehicles, etc.) for the purpose of exchanging ideas on the state of the art in computational tools and techniques