High Performance Continuously Variable Transmission Control Through Robust Control-Relevant Model Validation

Author(s):  
Tom Oomen ◽  
Stan van der Meulen

Optimal operation of continuously variable transmissions (CVTs) is essential to meet tightening emission and fuel consumption requirements. This is achieved by accurately tracking a prescribed transmission ratio reference and simultaneously optimizing the internal efficiency of the CVT. To reduce the power losses in a CVT, the absolute pressure levels are lowered, which increases the sensitivity to torque disturbances and increases the importance of disturbance feedforwards. This requires a high performance feedback controller for the hydraulic actuation system in a CVT. The aim of this paper is to develop a multivariable feedback controller for the hydraulic actuation system that is robust with respect to the varying system dynamics that are induced by the varying operating conditions, including transmission ratio changes. Hereto, new connections between system identification and robust control are exploited to achieve high performance. As a result, the varying system dynamics are directly evaluated in terms of closed-loop performance objectives. Subsequent robust control design reveals an increase of the control performance of almost a factor two in terms of the criterion value. This leads to improved simulated and measured closed-loop step responses, including a decrease in settling time from 0.4 s to 0.2 s. Finally, the designed robust controller is successfully validated in a standardized driving cycle experiment.

2014 ◽  
Vol 551 ◽  
pp. 337-343
Author(s):  
Hui Chen ◽  
Yong Ling Fu ◽  
Juan Chen ◽  
He Song Liu

With the development of the advanced precision-guided missile and anti-missile system, high precision, high penetration ability and Low energy consumption have become an important direction for the missile. A new missile electro-hydraulic actuation system with dual independent closed-loop is put forward with the trend of high performance and energy-saving, and then the operating principle and process are discussed. Finally the accurate mathematical model is established, and the influence of the different basic pressure on the dynamic performance is analyzed. The simulation results show that the new proposed scheme has made great improvements in reducing the zero-control current of the system, but the efficiency and performance of the actuation system should be considered integrated due to the decrease of the dynamic performance, so it is practical for the future development of the missile electro-hydraulic actuation system.


Author(s):  
Dingding Cheng ◽  
Lijun Liu ◽  
Zhen Yu

Traditional steady-state control methods are applied to turbofan engines operating in the small region near certain operating conditions, which need to switch controllers for operating in the large region and then may lead to instability and performance degradation of the closed-loop system. In this paper, a novel multivariable nonlinear robust control method for turbofan engines is proposed to improve the control performance within the large region. To enlarge the controllable region, a polynomial state-space model describes the nonlinear characteristics of turbofan engines. Based on the analysis of the closed-loop control system, by using the Lyapunov function theorems, a polynomial robust controller is designed to ensure the stability and desired nonlinear control performance of turbofan engines. Compared with the classical PI, mixed sensitivity, and H∞ control, simulation results show that the proposed method has better transient responses, disturbance rejection, and other control performance for the turbofan engine within the large region.


Author(s):  
Massimo Rundo ◽  
Raffaele Squarcini

The paper presents two displacement controls for IC Engine lubricating vane pumps. The main feature is the variable setting of the absolute pressure limiter that can switch from a high to a low level when a minimum threshold value of engine speed or oil temperature is exceeded. This is obtained by venting the displacement actuator of the pump by means of a two positions electrovalve or a temperature sensitive valve. Aim is the reduction of the circuit pressure in the less critical engine operating conditions in order to decrease the absorbed torque. These controls are contrasted with a traditional fixed setting device in terms of overall energy absorbed by the pump in the NEDC cycle. Comparisons are performed with a lumped parameters simulation model able to replicate the operating conditions encountered by the pump during the driving cycle, in terms of oil temperature and circuit permeability. Outcomes from simulation have been validated by experimental tests on pumps prototypes. Tests have been performed on a rig where the load on the pump is generated by a proportional throttle valve controlled in a closed loop in order to reproduce, for each temperature and velocity condition, the resistance of the lubricating circuit. The study brings to evidence that with both systems a significant reduction of the absorbed energy can be achieved in the NEDC without detrimental effects on engine lubrication.


2012 ◽  
Vol 542-543 ◽  
pp. 769-774
Author(s):  
Qun Ling Yu ◽  
Na Bai ◽  
Yan Zhou ◽  
Rui Xing Li ◽  
Jun Ning Chen ◽  
...  

A new technique for reducing the offset of latch-type sense amplifier has been proposed and effect of enable signal voltage upon latch-type sense amplifier offset in SRAM has been investigated in this paper. Circuit simulation results on both StrongARM and Double-tail topologies show that the standard deviation of offset can be reduced by 31.23% (StrongARM SA) and 25.2% (Double-tail SA) , respectively, when the voltage of enable signal reaches 0.6V in TSMC 65nm CMOS technology. For a column of bit-cell (1024 bit-cell), the total speed is improved by 14.98% (StrongARAM SA) and 22.26% (Double-tail SA) at the optimal operation point separately, and the total energy dissipation is reduced by 30.45% and 29.47% with this scheme.


1985 ◽  
Vol 65 (2) ◽  
pp. 285-298 ◽  
Author(s):  
J. E. KRUGER ◽  
B. A. MARCHYLO

Chromatographic conditions were optimized and three commercially available columns were evaluated for separation of alcohol-soluble storage proteins of Neepawa wheat using reversed-phase high-performance liquid chromatography (RP-HPLC). Optimal separation was achieved using an extracting solution of 50% 1-propanol, 1% acetic acid, and 4% dithiothreitol and an HPLC elution time of 105 min at a flow rate of 1.0 mL/min. HPLC columns evaluated (SynChropak RP-P, Ultrapore RPSC and Aquapore RP-300) varied in selectivity and resolution. The column providing the greatest versatility was Aquapore RP-300 available in cartridge form. Sodium dodecyl sulfate gradient-gel electrophoresis analysis of protein peaks resolved by RP-HPLC indicated that many of the eluted peaks contained more than one protein species. Chromatographic protein patterns obtained for Neepawa wheat grown at different locations and in different years were qualitatively the same.Key words: Protein, high-performance liquid chromatography, wheat


Author(s):  
Cesar A. Lopez Martinez ◽  
R. van de Molengraft ◽  
M. Steinbuch

Author(s):  
Hanz Richter ◽  
Kedar B. Karnik

The problem of controlling the rectilinear motion of an open container without exceeding a prescribed liquid level and other constraints is considered using a recently-developed constrained sliding mode control design methodology based on invariant cylinders. A conventional sliding mode regulator is designed first to address nominal performance in the sliding mode. Then an robustly-invariant cylinder is constructed and used to describe the set of safe initial conditions from which the closed-loop controller can be operated without constraint violation. Simulations of a typical transfer illustrate the usefulness of the method in an industrial setting. Experimental results corresponding to a high-speed transfer validate the theory.


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