48,743 research outputs found
Nonsmooth-Optimization-Based Bandwidth Optimal Control for Precision Motion Systems
Precision motion systems are at the core of various manufacturing equipment.
The rapidly increasing demand for higher productivity necessitates higher
control bandwidth in the motion systems to effectively reject disturbances
while maintaining excellent positioning accuracy. However, most existing
optimal control methods do not explicitly optimize for control bandwidth, and
the classic loop-shaping method suffers from conservative designs and fails to
address cross-couplings, which motivates the development of new control
solutions for bandwidth optimization. This paper proposes a novel bandwidth
optimal control formulation based on nonsmooth optimization for precision
motion systems. Our proposed method explicitly optimizes the system's MIMO
control bandwidth while constraining the H-infinity norm of the closed-loop
sensitivity function for robustness. A nonsmooth optimization solver, GRANSO,
is used to solve the proposed program, and an augmented quadratic programming
(QP)--based descent direction search is proposed to facilitate convergence.
Simulation evaluations show that the bandwidth optimal control method can
achieve a 23% higher control bandwidth than conventional loop-shaping design,
and the QP-based descent direction search can reduce iteration number by 60%,
which illustrates the effectiveness and efficiency of the proposed approach
Transcending the Acceleration-Bandwidth Trade-off: Lightweight Precision Stages with Active Control of Flexible Dynamics
Micro/Nano-positioning stages are of great importance in a wide range of
manufacturing machines and instruments. In recent years, the drastically
growing demand for higher throughput and reduced power consumption in various
IC manufacturing equipment calls for the development of next-generation
precision positioning systems with unprecedented acceleration capability while
maintaining exceptional positioning accuracy and high control bandwidth.
Reducing the stage's weight is an effective approach to achieving this goal.
However, the reduction of stages' weight tends to decrease its structural
resonance frequency, which limits the closed-loop control bandwidth and can
even cause stability issues. Aiming to overcome the aforementioned challenge
and thus create new lightweight precision stages with substantially improved
acceleration capability without sacrificing stage control performance, this
research presents a novel sequential structure and control design framework for
lightweight stages with low-frequency flexible modes of the stage being
actively controlled. Additional actuators and sensors are placed to actively
control the flexible structural dynamics of the lightweight stage to attain
high control bandwidth. A case study is simulated to evaluate the effectiveness
of the proposed approach, where a stage weight reduction of 24% is demonstrated
compared to a baseline case, which demonstrates the potential of the proposed
design framework. Experimental evaluation of the designed stage's motion
performance will be performed on a magnetically levitated linear motor platform
for performance demonstration.Comment: arXiv admin note: substantial text overlap with arXiv:2301.04208;
text overlap with arXiv:2309.1173
STOL Simulation Requirements for Development of Integrated Flight/propulsion Control Systems
The role and use of simulation as a design tool in developing integrated systems where design criteria is largely unavailable is well known. This paper addresses additional simulation needs for the development of Integrated Flight/Propulsion Control Systems (IFPCS) which will improve the probability of properly interpreting simulation results. These needs are based on recent experience with power approach flying qualities evaluations of an advanced fighter configuration which incorporated Short Takeoff and Landing (STOL) technologies and earlier experiences with power approach flying qualities evaluations on the AFTI/F-16 program. The use of motion base platforms with axial and normal degrees of freedom will help in evaluating pilot coupling and workload in the presence of high frequency low amplitude axial accelerations produced by high bandwidth airspeed controllers in a gusty environment
High-performance control of dual-inertia servo-drive systems using low-cost integrated SAW torque transducers
Abstract—This paper provides a systematic comparative
study of compensation schemes for the coordinated motion
control of two-inertia mechanical systems. Specifically, classical proportional–integral (PI), proportional–integral–derivative (PID), and resonance ratio control (RRC) are considered, with an enhanced structure based on RRC, termed RRC+, being proposed. Motor-side and load-side dynamics for each control structure are identified, with the “integral of time multiplied by absolute
error” performance index being employed as a benchmark metric. PID and RRC control schemes are shown to be identical from a closed-loop perspective, albeit employing different feedback sensing mechanisms. A qualitative study of the practical effects of employing each methodology shows that RRC-type structures
provide preferred solutions if low-cost high-performance torque transducers can be employed, for instance, those based on surface acoustic wave tecnologies. Moreover, the extra degree of freedom afforded by both PID and RRC, as compared with the basic PI, is shown to be sufficient to simultaneously induce optimal closed-loop performance and independent selection of virtual inertia ratio. Furthermore, the proposed RRC+ scheme is subsequently
shown to additionally facilitate independent assignment
of closed-loop bandwidth. Summary attributes of the investigation are validated by both simulation studies and by realization of the methodologies for control of a custom-designed two-inertia system
A novel linear direct drive system for textile winding applications
The paper describes the specification, modelling, magnetic design, thermal characteristics and control of a novel, high acceleration (up to 82g) brushless PM linear actuator with Halbach array, for textile package winding applications. Experimental results demonstrate the realisation of the actuator and induced performance advantages afforded to the phase lead, closed-loop position control scheme
High-speed noise-free optical quantum memory
Quantum networks promise to revolutionise computing, simulation, and
communication. Light is the ideal information carrier for quantum networks, as
its properties are not degraded by noise in ambient conditions, and it can
support large bandwidths enabling fast operations and a large information
capacity. Quantum memories, devices that store, manipulate, and release on
demand quantum light, have been identified as critical components of photonic
quantum networks, because they facilitate scalability. However, any noise
introduced by the memory can render the device classical by destroying the
quantum character of the light. Here we introduce an intrinsically noise-free
memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We
consequently demonstrate for the first time successful storage of GHz-bandwidth
heralded single photons in a warm atomic vapour with no added noise; confirmed
by the unaltered photon statistics upon recall. Our ORCA memory platform meets
the stringent noise-requirements for quantum memories whilst offering technical
simplicity and high-speed operation, and therefore is immediately applicable to
low-latency quantum networks
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