In wind tunnel tests, the pose of the aircraft model in wire-driven parallel suspension system (WDPSS) is determined by driving several wires. Pose measurement is very important for the study of WDPSS. Using machine vision technology, Monocular Vision Measurement System has been constructed to estimate the pose of the aircraft model by applying a camera calibration, by extracting corresponding control points for the aircraft model, and by applying several homogeneous transformations. This article describes the programs of the measurement system, measurement principle and data processing methods which is based on HALCON to achieve the Solution of the pose of aircraft model. Through experiments, practical feasibility of the system is validated.
In the wire-driven parallel suspension system, because manufacturing and assembling deviations exist, the expected control accuracy can not be reached. A mathematical model of wire-driven parallel manipulators is established. Effects of the deviations eliminated can improve the accuracy of the mathematical model. Particle swarm optimization (PSO) is a robust stochastic evolutionary computation technique, which is very easy to understand and implement. Particle swarm optimization is used to calculate model deviations and find values of the deviations. The results obtained by the particle swarm optimization algorithm can update the mathematical model of the wire-driven parallel manipulators and improve the control accuracy of the wire-driven suspension system.
This paper presents an optimized write driver used in Phase change memory (PCM). To pursue fast RESET/SET operation, the proper clock scheme is applied, with the maximum frequency at about 200MHz. The write driver uses current pulses at a fixed frequency to successfully write into memory cells. Compared with the traditional SET operation, the novel dual-pulse SET operation divides the program pulse into 2 periods: pre-programming period provides large energy to cross the threshold-switching fast, programming period quenches the phase change resistance to that of the crystalline state. The optimization of the write operation decrease the program time and improves the resistance distribution.
Resistance distributions of the crystalline (SET) state and amorphous (RESET) state for phase change memory (PCM) are experimentally investigated at the array level. The RESET distribution shows a low resistance tail, which potentially affects the reading margin of the chip. These tail cells are divided into two types by resistance programming current (R-IP) and current voltage (I-V) characteristics. Finally, approaches of improving the integration process to remove the Type-1 tail cells and optimizing the programming operation to repair the Type-2 tail cells are proposed.
An 8Mb phase change random access memory (PCRAM) has been developed by a 130nm 4-ML standard CMOS technology based on the Resistor-on-Via-stacked-Plug (RVP) storage cell structure. This phase change resistor is formed after CMOS logic fabrication. PCRAM can be embedded without changing any logic device and process. The memory cell selector is implemented by a standard 1.2V NMOS device. Aimed at the resistance distributions, lowering the operation current and improving the bit yield, some methods are used to optimize the design of the chip.
A write driver for PCM is designed to improve reliability and bit yield in the write operation, due to the distributions during the phase change process. And the PCM cell can be injected by current or voltage respectively. Meanwhile, owing to the possible variations of the SET process parameters, the designed circuit can generate either multiple stepdown current pulse or multiple step-down voltage pulse. The circuit is developed based on SMIC 130 nm CMOS standard technology. Compared to the traditional constant current pulse programming, the test results show that the proposed multiple step-down current generator for SET operation can improve the uniformity of resistance and bit yield.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.