Rigid Body Dynamics Algorithms presents the subject of computational rigid-body dynamics through the medium of spatial 6D vector notation. It explains how to model a rigid-body system and how to analyze it, and it presents the most comprehensive collection of the best rigid-bodydynamics algorithms to be found in a single source. The use of spatial vector notation greatly reduces the volume of algebra which allows systems to be described using fewer equations and fewer quantities. It also allows problems to be solved in fewer steps, and solutions to be expressed more succinctly. In addition algorithms are explained simply and clearly, and are expressed in a compact form. The use of spatial vector notation facilitates the implementation of dynamics algorithms on a computer: shorter, simpler code that is easier to write, understand and debug, with no loss of efficiency.

Rigid Body Dynamics Algorithms

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1065&context=usafresearch

A review of space robotics technologies for on-orbit servicing

https://repositorium.sdum.uminho.pt/bitstream/1822/19623/1/6.7.32%202012.pdf

Compliant contact force models in multibody dynamics : evolution of the Hertz contact theory

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

https://science.sciencemag.org/content/sci/312/5778/1350.full.pdf

Touchdown of the Hayabusa spacecraft at the Muses Sea on Itokawa.

A general and comprehensive analysis on the continuous contact force models for soft materials in multibody dynamics is presented throughout this work. The force models are developed based on the foundation of the Hertz law together with a hysteresis damping parameter that accounts for the energy dissipation during the contact process. In a simple way, these contact force models are based on the analysis and development of three main issues: (i) the dissipated energy associated with the coefficient of restitution that includes the balance of kinetic energy and the conservation of the linear momentum between the initial and final instant of contact; (ii) the stored elastic energy, representing part of initial kinetic energy, which is evaluated as the work done by the contact force developed during the contact process; (iii) the dissipated energy due to internal damping, which is evaluated by modeling the contact process as a single degree-of- freedom system to obtain a hysteresis damping factor. This factor takes into account the geometrical and material properties, as well as the kinematic characteristics of the contacting bodies. This approach has the great merit that can be used for contact problems involving materials with low or moderate values of coefficient of restitution and, therefore, accommodate high amount of energy dissipation. In addition, the resulting contact force model is suitable to be included into the equations of motion of a multibody system and contributes to their stable numerical resolution. A demonstrative example of application is used to provide the results that support the analysis and discussion of procedures and methodologies described in this work.

/pdf/on-the-continuous-contact-force-models-for-soft-materials-in-38io7v5muo.pdf

On the continuous contact force models for soft materials in multibody dynamics

Literature survey of contact dynamics modelling

Canadian researchers have proposed a design for a new radio telescope consisting of an array of very large ree ectors. A largemultitethered aerostat will be used to support each ree ector’ s receiver. The length of each tether can be adjusted by ground-based winches, and active control is used to overcome the effects of wind turbulence on the aerostat. To aid in the system’ s mechanical and controller design, a computer model has been developed, including models of the tethers and the aerostat. Two types of aerostat have been considered: spherical and streamlined. A wind turbulence model is incorporated to provide disturbance to the system. Controllers are used to adjust the tether lengths based on feedback of the receiver’ s position. The model is used to optimize the control gains. We e nd that, with 50 kW available at each winch, it is possible to maintain the receiver’ s position within 85 cm of its desired location, even in the worst-case cone guration.

Dynamics/Control of a Radio Telescope Receiver Supported by a Tethered Aerostat

In this paper, the dynamics and biomimetic control of an artificial finger joint actuated by two opposing one-way shape memory alloy (SMA) muscle wires that are configured in a double spring-biased agonist–antagonist fashion is presented. This actuation system, which was described in Part I, forms the basis for biomimetic tendon-driven flexion/extension and abduction/adduction of the artificial finger. The work presented in this paper centres on thermomechanical modelling of the SMA wire, including both major and minor hysteresis loops in the phase transformation model, and co-operative control strategy of the agonist–antagonist muscle pair using a pulse-width-modulated proportional-integral-derivation (PWM–PID) controller. Parametric analysis and identification are carried out based on both simulation and experimental results. The performance advantage of the proposed co-operative control is shown using the metacarpophalangeal joint of the artificial finger.

A shape memory alloy based tendon-driven actuation system for biomimetic artificial fingers, part ii: Modelling and control

https://www.tpbin.com/Uploads/Subjects/a7ae18c1-a03b-454f-88c0-cbdeedc6ef78.pdf

Fuzzy PWM-PID control of cocontracting antagonistic shape memory alloy muscle pairs in an artificial finger

Using an order N Lagrangian formulation, the paper studies attitude control of a rigid platform supporting a flexible tether connected to a rigid satellite. The system, in an arbitrary orbit, is free to undergo three-dimensional motion in both rigid and flexible degrees of freedom. As can be expected, the governing equations of motion, in general, are highly nonlinear, nonautonomous, and coupled, and are amenable only to numerical integration. The control is achieved through time dependent offset of the tether attachment point, as determined through the Liapunov method, thus providing regulated amount of tether tension induced damping moment. Results suggest that the controller is quite successful in stabilizing the platform about its nominal equilibrium position in a few orbits, even in the presence of relatively large disturbances. Furthermore, extensive parametric study suggests that the controller is quite versatile in imparting any desired orientation to the platform. This would enable the system to ...

Gabriele Gilardi

Papers

Literature survey of contact dynamics modelling

Dynamics/Control of a Radio Telescope Receiver Supported by a Tethered Aerostat

A shape memory alloy based tendon-driven actuation system for biomimetic artificial fingers, part ii: Modelling and control

Fuzzy PWM-PID control of cocontracting antagonistic shape memory alloy muscle pairs in an artificial finger

Attitude Control of Space Platform Based Tethered Satellite System