Disturbance Observer-Based Predictive Functional Critical Control of a Table Drive System
This paper addresses a control system design for a table drive system based on the disturbance observer (DOB)-based predictive functional critical control (PFCC). To empower the previously developed DOB-based PFC to handle constraints on controlled outputs, we propose to take a critical control approach. To this end, we derive the transfer function representation of the PFC controller and yield a detailed design procedure. The effectiveness of the proposed method is confirmed through an experimental evaluation.
Improving Tracking Performance of Predictive Functional Control Using Disturbance Observer and Its Application to Table Drive Systems
A practical approach for improving tracking performance of the predictive functional control (PFC) is proposed. The disturbance observer is utilized to nominalize the actual plant and to reduce the predicted output error in the PFC algorithm by canceling not only constant but also high-order disturbances. The proposed control scheme is experimentally validated on a single axis table drive system and is compared with the standard PFC and the industrial cascade control. The experimental results prove the effectiveness of the proposed disturbance observer-based PFC scheme.
Low-temperature thermal expansion of PEEK, HTA and some of their composites reinforced with carbon fibres
Abstract The thermal expansion of poly(ether ether ketone), a modification of poly (ether sulphone) and carbon fibre reinforced composites of these polymers has been measured over the range −153 to 27°C with a push-rod diameter. Where other measurements are available for comparison, agreement is obtained within experimental scatter. Some multidirectional composites are tested and the measured values of thermal expansion are explained qualitatively. It is thought that the specimen size has had a significant effect on these results. The longitudinal and transverse coefficients of thermal expansion of Hercules AS4 fibre have been calculated.