Time Based Stiction Compensation

Workload control (WLC) systems can be seen as a natural extension of input-output control systems which allow both the control of jobs into the shop and the control of capacity which affects the flow of finished goods out of the shop. In previous research, it has been shown that WLC can help to reduce manufacturing lead times, even if the total workload processed by the shop in a given time period is maintained at a constant rate. However, the relative contributions of the input control mechanisms versus the output control mechanisms have not been clearly determined. This paper seeks to explore this which affects the flow of finished goods out of the shop. In previous research, it has been shown that WLC can help to reduce manufacturing lead times, even if the total workload processed by the shop in a given time period is maintained at a constant rate. However, the relative contributions of the input control mechanisms versus the output control mechanisms have not been clearly determined. This paper seeks to explore this issue using a simulation of a real job shop, in which the WLC system that has been developed at Lancaster University is used. It explores the use of input control alone and the use of input control plus output control. In addition, the relation between workload and various performance measures, such as lead time, queueing time and capacity utilisation, is explored. The results of the experiments show that one should consider input control and output control as two levers of control that are both to be pulled rather than relying on the single lever of stopping the input when the WIP reaches some preset level.

<div class="htmlview paragraph">A large percentage of on-highway tractors today have air suspensions. Air suspensions require some type of control system to adjust the ride height. This system is usually referred to as a Load Leveling System. These systems come in a variety of different configurations but all basically have the same functions. When designed correctly, the system can reduce driveline vibration, reduce air consumption (improving compressor life and fuel efficiency), provide an accurate 5<sup>th</sup> wheel height and improve the ride quality.</div> <div class="htmlview paragraph">This paper explores how the characteristics of the leveling system affect the roll stability. One and Two-valve systems are considered, as well as, the position of the valve, response times, valve deadband and the systems response to an off-center load.</div> <div class="htmlview paragraph">Notably not every conceivable condition has been considered. The situations chosen for analysis are meant to provide an overview of how the characteristics of the leveling system can have an influence on the rollover threashold. The fact that some of the situations may suggest one leveling system configuration has a better performance than another is not sufficient to conclude that that system is universally better than the other system in practical applications.</div> <div class="htmlview paragraph">With that said, the results of the analysis do suggest that under specific conditions, certain configurations may have some influence on the rollover threashold. When the vehicle is loaded correctly and the slow response of the valve and valve deadband are considered, the one-valve system used by most OEMs today results in slightly better rollover threashold than a two valve system. If the response times of the valves are ignored or the duration of the roll event lasts a substantial amount of time, the two-valve system provides a slightly better result.</div> <div class="htmlview paragraph">If the cargo is loaded significantly away from the center of the vehicle track, a two-valve system will provide a better rollover threashold. However, the two-valve system may hide the problem from the driver where a one-valve system would allow the initial roll angle of the chassis to be non-zero, increasing the odds that the off-center load will be detected and corrected. The lateral position of the leveling valve will very slightly have an influence on the system. A system that is design not to change the air volume during roll conditions would be preferred if packaging allows this configuration. Overall, the contribution of this parameter is minimal even ignoring the slow response of the leveling system.</div>

Drawing on the dominant logic perspective, this study argues that entrepreneurial orientation (EO) can generate an entrepreneurial dominant logic among new ventures that facilitate making and implementing decisions to experiment with entrepreneurial initiatives. Yet, the decisions are associated with high uncertainty. Since new ventures cannot endure high levels of uncertainty, to harness the potential of EO they should put in place proper control systems to reduce uncertainty associated with EO. This study examines the moderating role of output control, behavior control, and input control in the relationship of EO to new venture performance. It finds that both output control and behavior control have positive moderating effects but input control plays a negative moderating role. The findings enrich our knowledge on the EO–performance linkage. Moreover, this study represents one of the first attempts to adopt the dominate logic perspective to illustrate EO phenomena, laying down a solid threshold over which to introduce the perspective to the EO literature. And, by combining EO and control systems in a moderating model this study responds to appeals for extending control systems into entrepreneurship studies and thereby contributes to research on control systems.

Reweighted adaptive bilinear filters for an active noise control system with a nonlinear secondary path

An express method for optimally tuning analog PI and PID controllers is considered. An integral quality criterion with minimizing the control output is proposed for optimizing control systems. The suggested criterion differs from existing ones in that the control output applied to the technological process is taken into account in a correct manner, due to which it becomes possible to maximally reduce the expenditure of material and/or energy resources in performing control of industrial equipment sets. With control organized in such manner, smaller wear and longer service life of control devices are achieved. A unimodal nature of the proposed criterion for optimally tuning a controller is numerically demonstrated using the methods of optimization theory. A functional interrelation between the optimal controller parameters and dynamic properties of a controlled plant is numerically determined for a single-loop control system. The results obtained from simulation of transients in a control system carried out using the proposed and existing functional dependences are compared with each other. The proposed calculation formulas differ from the existing ones by a simple structure and highly accurate search for the optimal controller tuning parameters. The obtained calculation formulas are recommended for being used by specialists in automation for design and optimization of control systems.

Model Based Predictive Networked Control Systems

제어계에서 제어성능을 개선시키기 위해서 많은 제어기법들이 제안되어왔다. 궤환제어계에서 일반적으로 제어기의 출력이 제어대상의 입력으로 사용된다. 그러나 불필요한 잡음이 제어기의 출력에 포함된다. 그러므로 이러한 잡<br/> 음을 제거하고 계의 응답특성을 개선시키기 위해서 전치보상기를 사용할 필요가 있다.<br/> 본 논문에서는 모델추종제어를 위한 전치보상기의 설계법을 I-PD 제어계에서 제안하였다. 제안한 전치보상기를신경망으로 구현하였고, 계의 응답특성이 어떤 조건하에서 변할 때 원하는 응답이 되도록 전치보상기의 이득이 자<br/> 동적으로 조정되도록 하였다.

Fuzzy logic control (FLC) system is a control system which is working based on error input data, rate of error, and accelaret of error of controlling variable. Using some rules of FAM (Fuzzy Associate Memory) which is constructed for resulting a decision can be used to actuator of controller. This paper is des-cribing about designing fuzzy logic as a control system for ship maneuvering, which is input for FLC are yaw error, yaw rate, and tracking error while the output of fuzzy logic control is command rudder signal. FLC con-sists of two units of controller; it is first controller unit work for autopilot and second controller unit for offset track. Interference function for FLC is Sugeno – Takagi which represent mathematic equation from input vari-able of FLC. Gain control of FLC based on least square estimation of error yaw, yaw rate, and output control signal relationship from LQR/LTR as a model reference control. Dynamic model of ship maneuvering has been derived on 3 dof with Clarke hydrodynamic coefficient. The capability of logic fuzzy control has been shown on simulation, for tanker ship model without interference or within interference. Robust of fuzzy logic control has been got from trajectory convergence error of yaw and yaw rate error when on turning simulation or off turning simulation toward the sector (0, 0).

A method of guidance is described for an autonomous guided vehicle (AGV) operating in a pre-defined and structured environment such as a warehouse or factory. The guidance system requires a series of data describing concatenated curved and straight-line segments to be passed to the vehicle as a representation of a planned path within its environment. The coordinate position of each line segment, the associated AGV direction, and the demand speed constitute a series of commands which are queued and then executed in sequence. In order to execute commands, the AGV is equipped with two-level sensor systems, ultrasonic transducers and odometry, which allow it to estimate and correct its global position continually. In addition to a queue of commands, the AGV also has a pre-programmed knowledge of the position of a number of correction boards within its environment. When the AGV passes such a correction board, it can measure its position relative to the board in the local frame of the board. This is then transformed into a global position correction. Position corrections appear as step disturbances to the control system. The control system is arranged so that it allows the vehicle to move back on to its planned trajectory after a position correction in a critically damped fashion.

Postural stability is reduced with age or neurological disorder and improved with certain types of training (e.g., Tai-chi) as evaluated by various measures using center of pressure (COP) during quiet standing. However, the implications of specific measures with respect to the underlying control mechanisms have remained unclear. PURPOSE: To investigate the influence of variation in the control system on the COP measures during quiet standing, using mathematical simulations. METHODS: A feedback model that represented the human body and the control system during quiet standing was built using an inverted pendulum, a proportional and derivative (PD) controller with a time delay (the neural controller) and another PD controller without a time delay (the mechanical controller). The angle of the pendulum was fed back to the controllers, and the output of the neural controller (corresponding to the motor command) was input into the neuro-muscular torque generator. The sum of the output of the neuro-muscular torque generator and of the mechanical controller represented the ankle torque. A driving noise was added to the motor command to simulate realistic body sway conditions. The gain combinations that robustly stabilized the entire system were used to simulate the COP fluctuations. The gains of the controllers and the noise amount were treated as variables. The statistical relationship between each measure and the controller gains or noise was assessed using the partial correlation analysis. Sixty thousand and five hundred combinations of the variables were tested in total. RESULTS: All gains correlated negatively with the time domain measures (r=-0.372 to-0.659) except the mean velocity, which correlated positively with each gain. The neural derivative gain correlated positively with the frequency domain measures (r =0.964 to 0.973). The proportional gains correlated with Hurst exponent positively for the short term region (r= 0.837 to 0.892) and negatively for the long term region (r=-0.828 to-0.883). The amount of noise correlated positively with time domain measures (r= 0.901 to 0.988) but not with frequency measures. CONCLUSIONS: Each COP measure is associated with the variation in the control system. As such, the COP measures have a potential for investigating or characterizing the control system of balance.

Optimum design, simulation and test of a new flow control valve with an electronic actuator for turbine engine fuel control system

US reconfirms anti-dumping duties on Indian & Chinese carbazole violet

In the past, the majority of research on governmental organizational control and the establishment of a control system focused on the possession of authority itself, but ignored the contribution of knowledge-based resources, which has been increasingly valued by researchers in recent years. Taking the perspective of knowledge-based resource, this thesis examines the relationship between control premises and control modes, and its influence on governmental organization in Taiwan. The research found: 1.intangible knowledge-based resource contribution also plays a key role in the control system; 2.knowledge-based resources has a significant influence on output control, process control, and social control; 3.the variables of governmental agencies and service units do not have different views on the knowledge resources and controlled mode. The results have enlarged the research scope of controlled theories in governmental organizations, thus providing a valuable reference for the design and application of a practical control system.

Control valves are an increasingly vital component of modern manufacturing around the world, since control valves are mechanical devices, their performance is less than ideal, and degrades over time. For a plant to perform optimally control valve performance must be tracked and maintained. Backlash is one of much invertible nonlinearity present in control valve, if a valve has some backlash, the loop will have a tendency to oscillate, which will get bigger and bigger as time goes by and will also make the loop slower to respond. At present, pneumatic valve Positioner is used which uses mechanical cam to correct the non-linear nature of control valves. Pneumatic valves Positioner typically are very simple and do not implement integral control. In this project a novel low cost Smart Positioner is designed and developed to improve the performance of control loops. A rotary potentiometer with a linear actuator is used to give feedback signals to the controller of the current position of the control valve. A specially designed control system which is cascade in nature increases the performance of the control system. The Position sensor control being a slave controller acts faster to position the valve and thereby avoiding backlash problem. The developed design is implemented in the Second Order Two Tank Level control system and the performance metrics such as Rise time, Settling time and Steady state errors evaluated found improved after implementing smart Positioner. The oscillation of control valve was found minimum compared to pneumatic Positioner which clearly an indication of reduced backlash in the system. The low cost smart Positioner is RVDT which fixed on a pinion rack and interfacing the proposed second order system using MATLAB for error analysis and LabVIEW software and NI DAQ6008 to run the proposed second order system.

Spark ignition engine performance and exhaust emissions are strongly affected by the fuel/air ratio used. A considerable amount of investigations have been carried out by engine manufacturers to control engine performance and meet exhaust emission standards of governmental agencies by developing control systems for some operating variables such as ignition timing(IT), Fuel Air Ratio(FAR), and Exhaust Gas Recirculation (EGR) This paper presents a fuzzy control system that measures exhaust temperature and operates a needle valve on the engine earburetor jet that enables the fuel to air ratio lo oscillate about a desired value. A group of experiments have been carried out to obtain the relationship between fuel to air ratio or (ɸ), Exhaust temperature and exhaust emissions. A group of fuzzy logic rules which relate exhaust temperature, to the desired speed with the position of a needle valve actuated by a stepping motor are prop osed. A beneficial of fuzzy control method was that the rules determined the characteristics of control system are interpreted by the operator. Experimental and simulated results show that the prop osed fuzzy system improves the fuel/air mixture quality.