Towards teleoperation with human-like dynamics: Human use of elastic tools

Variable stiffness actuators undergo lower peak force in contacts compared to their rigid counterparts, and are thus safer for human-robot interaction. Furthermore, they can store energy in their elastic element and can release it later to achieve human-like dynamic movements. However, it is not clear how to integrate them in teleoperator...

Dynamics motion simulation of the Hermes robot arm subjected to constraints

During operations with a manipulator arm situations will occur when the manipulator end-effector is, or comes, in contact with its environment. The dynamics equations, which describe the motion of the manipulator, can be represented by an ordinary differential equation for the free motion and an additional algebraic (in)equality for the motion...

Linear recursive formulation of flexible multi-body space system dynamics

Numerical simulation of the dynamics of multi-body systems constitutes a central part in the design and analysis of modern space-based systems. The report focuses on the development of a recursive formulation of the dynamics of flexible spacecraft-robotmanipulator systems, suitable for efficient numerical simulation. The rather well-established...

Modelling dynamical systems with equality state-space constraints

A mathematical theory for modelling dynamical systems with equality state-space constraints is presented. The dynamic behaviour of these systems is represented by a combination of differential and algebraic equations. It Is shown that the freedom offered by control is essential to obtain other, mathematically equivalent formulations. The notion...

Predesign of a simulator for inverse robot kinematics

An inverse robot kinematics method is being developed that is to be applicable to any sequential rigid robot. In this report, first requirements are identified and a survey of existing methods is given. An. evaluation of these methods with respect to the requirements then shows that a method based on optimization is the best candidate. It...

Numerical solution of dynamical systems with equality state-space constraints

Numerical simulation of constrained dynamical systems is known to exhibit stability problems even when the unconstrained system can be simulated in a stable manner. We show that not the constraints themselves, but the transformation of a continuous set of equations to a discrete set of equations is the true source of the stability problem....

Study on efficient numerical time-integration methods for simulation of multi-body systems

This report describes the results of an evaluation of numerical integration schemes to be used for the digital simulation of second order ordinary differential equations (ODE's) which are characteristic for multibody systems such as space manipulators. The study focuses on dedicated schemes for this type of systems. Main attention is paid to the...

Quasi-recursive dynamics equations for spacecraft-based flexible robotic manipulators

The report contains the development of the dynamics equations of a spacecraftmanipulator system with chain topology. The spacecraft may be flexible. The attached manipulator consists of an arbitrary number of links, connected by single degree-of-freedom rotational joints. None, any, or all of the links may be flexible. A rigid or flexible...

Equivalent flexibility modelling for the recursive simulation of robot manipulator dymamics

The report focuses on the mathematical modelling of the dynamics of spacecraft based manipulators displaying structural flexibility in their links. The equations of motion must be cast in a form suitable for efficient numerical simulation. Equations of motion found in literature are usually written in the form of an augmented system of...

Flexible space-based robot modelling and real-time simulation

The Hermes manipulation system (HERA) is a sophisticated space manipulator system, which has to perform tasks ranging from berthing to tool operation in various operational modes from fully automatic to purely manual. Development and qualification of such a space-based manipulator must be supported by computer simulation facilities. The HERA...

Equivalent flexibility modelling: A novel approach towards recursive simulation of flexible spacecraft-manipulator dynamics

For the simulation of rigid spacecraft manipulator dynamics there exists efficient recursive software. Extension of this software for the simulation of flexible spacecraft-manipulator dynamics would have important advantages. In this paper the method of Equivalent Flexibility Modelling (EFM) is outlined. Each flexible body is re-modelled as a...

A reference model for the dynamics of a flexible, spacecraft-based manipulator

The objective of the study is to develop the equations of motion of a single link, flexible manipulator, attached to an orbiting spacecraft. A payload may be attached to the end-effector of the manipulator. Starting point is d'Alembert's principle, with displacements described by hybrid coordinates. The equations of motion for the two-body...

Dynamics modelling, simulation, and control of a spacecraft/manipulator system

Four well-known formalisms for mathematical modelling of the dynamics of a spacecraft/manipulator system are derived from the unifying d'Alembert principle. The Newton-Euler formalism is discussed in more detail, as it allows efficient numerical simulation. An algorithm is defined for the control of the manipulator end-effector motion in...