26 research outputs found
Realization of a special class of admittances with one damper and one inerter for mechanical control
published_or_final_versio
Realization of three-port spring networks with inerter for effective mechanical control
published_or_final_versio
Realizability of n-port resistive networks with 2n terminals
In this paper, we consider the realizability problem of n-port resistive networks containing 2n terminals. A necessary and sufficient condition for any real symmetric matrix to be realizable as the admittance of an n-port resistive network containing 2n terminals is obtained. The condition is based on the existence of a parameter matrix. We then focus on a three-port resistive network containing six terminals. A necessary and sufficient condition is derived for any real symmetric matrix to be realizable as the admittance of a three-port resistive network containing six terminals and at most five positive elements, whose topological structure is properly restricted. © 2013 IEEE.published_or_final_versio
Passive Realizations of Series Elastic Actuation: Effects of Plant and Controller Dynamics on Haptic Rendering Performance
We introduce minimal passive physical equivalents of series (damped) elastic
actuation (S(D)EA) under closed-loop control to determine the effect of
different plant parameters and controller gains on the closed-loop performance
of the system and to help establish an intuitive understanding of the passivity
bounds. Furthermore, we explicitly derive the feasibility conditions for these
passive physical equivalents and compare them to the necessary and sufficient
conditions for the passivity of S(D)EA under velocity sourced impedance control
(VSIC) to establish their relationship. Through the passive physical
equivalents, we rigorously compare the effect of different plant dynamics
(e.g., SEA and SDEA) on the system performance. We demonstrate that passive
physical equivalents make the effect of controller gains explicit and establish
a natural means for effective impedance analysis. We also show that passive
physical equivalents promote co-design thinking by enforcing simultaneous and
unbiased consideration of (possibly negative) controller gains and plant
parameters. We demonstrate the usefulness of negative controller gains when
coupled to properly designed plant dynamics. Finally, we provide experimental
validations of our theoretical results and characterizations of the haptic
rendering performance of S(D)EA under VSIC
Semi-active suspension with semi-active inerter and semi-active damper
This paper investigates the application of semi-active inerter in semi-active suspension. A semi-active inerter is defined as an inerter whose inertance can be adjusted within a finite bandwidth by on-line control actions. A force-tracking approach to designing semi-active suspension with a semi-active inerter and a semi-active damper is proposed, where the target active control force derived by LQR control in the 'Reciprocal State-Space' (RSS) framework is tracked by controlling the semi-active damping coefficient and semi-active inertance. One of the advantages of the proposed method is that it is straightforward to use the acceleration information in the controller design. Simulation results demonstrate that the semi-active suspension with a semi-active inerter and a semi-active damper can track the target active control force much better than the conventional semi-active suspension (which only contains a semi-active damper) does. As a consequence, the overall performance in ride comfort, suspension deflection and road holding is improved, which effectively demonstrates the necessity and the benefit of introducing semi-active inerter in vehicle suspension.preprin