Inertia

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

A dual model-free control of underactuated mechanical systems, application to the inertia wheel inverted pendulum

Abstract: This paper deals with a new method allowing recent model-free control technique to deal with underactuated mechanical systems for stable limit cycles generation. A model-free controller is designed in order to track some parametrized reference trajectories. A second model-free controller is then designed using trajectories' parameters as control inputs in order to stabilize the internal dynamics. The proposed method is applied to a real underactuated mechanical system: the inertia wheel inverted pendulum. Numerical simulations as well as real-time experiments are presented showing the effectiveness of the proposed control method and its robustness toward external disturbances.

Application of matrix displacement methods in the study of panel flutter.

Abstract: A finite element approach to panel flutter problem has been attempted in this analysis. A method to derive the aerodynamic influence coefficient matrices kinematically consistent with the stiffness and inertia matrices, has been suggested. These matrices have been employed in the formulation of the dynamic equations of motion and the system of equations solved for their complex eigen values and vectors by the usual methods. This approach is general and is applicable to any boundary conditions. Some examples have been worked out, on a computer, for simply supported panels in supersonic flow and the results found to be in good agreement with those from other conventional methods.

Dynamics analysis of a parallel hip joint simulator with four degree of freedoms (3R1T)

Abstract: For a hip joint simulator with a 3SPS+1PS spatial parallel manipulator as the core module, a formulation based on the Kane equation was derived for the dynamic characteristics of the simulator from the kinematics analysis of the model. The relationships of the velocities and accelerations between the moving platform and active branched-chains were deduced. The velocity and angular velocity components of the moving platform were served as the generalized velocities. And the dynamic model was established by obtaining the generalized active forces and inertial forces. Then the driving forces and powers of the active branched-chains and the constraint reaction forces of the intermediate branched-chain were simulated in the numerical method. The results showed that the active driving forces of the branched-chains reached their respective maximum when the moving platform rotated into 0.13∘ around X-axis, 2∘ around Y-axis, and 18∘ around Z-axis. And the intermediate branched-chain needed to balance the driving and inertia forces, as well as support the moving platform and load the force of hydraulic cylinder. Therefore, the maximum constraint reaction force of the intermediate branched-chain is along the Z-axis. The research works provided a theoretical basis for the design of the active branched-chains driving system and the structural parameters of the intermediate branched-chain, as well as for the control system.

Resonant-type inertia linear motor based on the harmonic vibration synthesis of piezoelectric bending actuator

Abstract: Traditional piezoelectric inertia motors are generally driven at the quasi-static frequency range, which results in a relatively slow moving speed. In this paper, a piezoelectric bending actuator was designed for a resonant-type inertia linear motor. The driving mechanism of the actuator was also studied. The actuator's movement in a periodical sawtooth-shaped waveform was generated by composing two sinusoidal resonant bending vibrations with a frequency ratio of 1:2. A prototype inertia motor was fabricated. Experimental results confirmed the effectiveness of the design. The no-load maximum speed was 28.2 mm/s with drive voltage of 300 Vp–p for a base frequency of 587 Hz. At a preload force of 9.6 N and a driving voltage of 400 Vp–p for the base frequency, the linear speed was 18.5 mm/s with 0.02 N drag load. The moving direction could be reversed by changing the driving voltage's phase.

An Improved Virtual Inertia Algorithm of Virtual Synchronous Generator

Abstract: Virtual synchronous generator (VSG) simulates the first-order motion equation of a synchronous generator (SG) with the algorithm. VSG can improve the system voltage and frequency support capabilities of a microgrid or a weak grid. It is now widely applied at a high penetration level of distributed generation (DG) systems. However, because there is a contradiction between active power steady-state deviation of VSG and dynamic impact regulation, the VSG running in grid-connected mode with existing strategies cannot meet the steady and dynamic control requirements. Thus, an improved virtual inertial control strategy of VSG is proposed in this paper. The active power impact is reduced effectively under the circumstance of damping coefficient D ω equal to 0 and a large inertia, thus the dynamic characteristic of active power is improved and its steady-state characteristic is maintained. Firstly, based on the analysis of the damping coefficient effect on the system dynamic process, two forms of improved virtual inertia algorithms are put forward by cascading a differential link into different positions of the first-order virtual inertia forward channel. Then, by comparing the characteristics of the system with the two improved algorithms, the improved virtual inertial strategy based on differential compensation is proven to be better, and the design of its parameters is analyzed. Finally, simulation and experimental results verify the effectiveness of the proposed algorithm.