Inertia

About: Inertia is a research topic. Over the lifetime, 12006 publications have been published within this topic receiving 164291 citations.

Inertia-Free Spacecraft Attitude Control Using Reaction Wheels

Abstract: This paper extends the continuous inertia-free control law for spacecraft attitude tracking derived in prior work to the case of three axisymmetric reaction wheels. The wheels are assumed to be mounted in a known and linearly independent, but not necessarily orthogonal, configuration with an arbitrary and unknown orientation relative to the unknown spacecraft principal axes. Simulation results for slew and spin maneuvers are presented with torque and momentum saturation.

Polynomial-Method-Based Design of Low-Order Controllers for Two-Mass Systems

Abstract: In this paper, low-order integral-proportional (IP), modified IP (m-IP), and modified integral-proportional-derivative (m-IPD) controllers are designed for the speed control of a two-mass system based on a normalized model and polynomial method. In order to have sufficient damping, the parameters of the controllers are determined through characteristic-ratio assignment under the principle that all the characteristic ratios should be larger than two. It is found that for an inertia ratio smaller than one-third, an IP controller can effectively suppress the vibrations with proper damping, while for a relatively larger inertia ratio, an m-IP controller (i.e., IP controller with an additional low-pass filter) is effective. m-IPD control is theoretically effective for a large inertia ratio. However, the necessity of a negative derivative gain leads to a very poor robustness. Both simulation and experimental results verified the effectiveness of the designed IP and m-IP controllers when the inertia ratio is relatively small. For the m-IPD controller, its poor robustness is demonstrated by introducing a large gear backlash in experiments, while the IP and m-IP controllers show promising results of a much better robustness against the gear backlash nonlinearity.

Sliding sheets: lubrication with comparable viscous and inertia forces

Abstract: A rigid plane thin sheet is sliding steadily at speed U close to a plane wall, in a fluid of kinematic viscosity v. The sheet is infinitely wide and is of length L in the direction of motion, and its leading edge is a distance h0 [Lt ] L from the wall. A solution is sought for arbitrary finite values of R = Uh20/νL. In the limit as e = h0/L→0, the problem reduces to that of solving the boundary-layer equation in the gap region between sheet and wall, and this is done here both by an empirical linearization, and by direct numerical methods. The solutions have the property that they reduce to those predicted by lubrication theory when R is small, and to those predicted by an inviscid small-gap theory when R is large. Special attention is paid to the correct entrance and exit conditions, and to the location of the centre of pressure.

Multi-objective bat algorithm with time-varying inertia weights for optimal design of passive power filters set

Abstract: In this study, a novel method is developed to optimise the design of passive power filters (PPFs). The proposed method is based on the famous bat algorithm (BA) and is expected to make the PPF design easier and more effective than conventional trial-and-error approaches. Furthermore, the effects of inertia weight variations on the performance of the proposed method are examined. To optimise performance, the most suitable inertia weight, with the best effects, will be selected. For solving multi-objective optimisation problems, a so-called external archive is also integrated into the proposed method. A case study of PPF design is also presented to demonstrate the accuracy, efficiency and superiority of the proposed method.

Motion capture based identification of the human body inertial parameters

Abstract: Identification of body inertia, masses and center of mass is an important data to simulate, monitor and understand dynamics of motion, to personalize rehabilitation programs. This paper proposes an original method to identify the inertial parameters of the human body, making use of motion capture data and contact forces measurements. It allows in-vivo painless estimation and monitoring of the inertial parameters. The method is described and then obtained experimental results are presented and discussed.