Proportional Solenoid Valves (PSV) have been successfully used in the hydraulic industry for many years due to the benefits associated with higher accuracy compared to on/off solenoid valves, and the robustness and cost compared to servo valves. Because the PSV plays an important role in the performance of a hydraulic system, a technique commonly referred to as Condition Monitoring Scheme (CMS) has been used extensively to monitor the progress of faults in the PSV. But before any CMS can be implemented on a system, it needs to be thoroughly tested for its reliability of fault detection since, a failure of the CMS to detect any potential fault can be economically disastrous, and dangerous in terms of the safety of personnel. The motivation of this research was to develop a fault simulator which could reliably and repeatedly induce user defined faults in the PSV and thereby aid in testing the efficacy of the CMS for monitoring such simulated faults.<p>Industry research has revealed that the most common mode of failure in spool valves is an increase in the friction between the spool and valve, due to wear, contamination and dirt, which renders the valve inoperable. In this research, a non-destructive fault simulator was developed which induced artificial friction faults in the PSV. The PSV consisted of two solenoids on the opposite sides of the valve spool by virtue of which, bi-directional position control could be achieved. The PSV with the spool and one of the solenoids was used as the system in which the faults were simulated, and the second solenoid was used an a fault simulator for inducing the desired friction characteristics in the system. <p>The friction characteristics induced in the valve were similar to those in the classical friction curve, i.e., stiction at low velocities and Coulomb and viscous friction at higher velocities. By employing a closed loop position control scheme, one of the solenoids was used to generate a linearly increasing velocity profile by virtue of which the desired friction characteristics could be induced in different velocity regimes. The other solenoid was used to generate the desired friction force. A closed loop force control strategy, which used the feedback from a force transducer, allowed for the accurate control of the friction characteristics. stiction was induced at low velocities by passing the required current in both the solenoids that resulted in no net force on the valve spool. Due to the absence of any driving force the spool was stalled at the desired location, thus achieving the same effect of stiction at low velocities. The coulomb and viscous friction were induced at higher velocities by employing an algorithm which was a function of the spool velocity. Different magnitudes of static, coulomb and viscous friction were induced to achieve the friction characteristics represented by the classical friction curve. Since the change in force characteristics of the valve results in a corresponding change in the current drawn by the position control solenoid, a rudimentary CMS for monitoring the current characteristics is presented. Based on the experimental results and validation using the CMS it was concluded that the fault simulator was able to accurately produce the desired frictional loading on the valve spool and was able to do so with a high degree of repeatability. Proportional Solenoid Valves (PSV) have been successfully used in the hydraulic industry for many years due to the benefits associated with higher accuracy compared to on/off solenoid valves, and the robustness and cost compared to servo valves. Because the PSV plays an important role in the performance of a hydraulic system, a technique commonly referred to as Condition Monitoring Scheme (CMS) has been used extensively to monitor the progress of faults in the PSV. But before any CMS can be implemented on a system, it needs to be thoroughly tested for its reliability of fault detection since, a failure of the CMS to detect any potential fault can be economically disastrous, and dangerous in terms of the safety of personnel. The motivation of this research was to develop a fault simulator which could reliably and repeatedly induce user defined faults in the PSV and thereby aid in testing the efficacy of the CMS for monitoring such simulated faults. Industry research has revealed that the most common mode of failure in spool valves is an increase in the friction between the spool and valve, due to wear, contamination and dirt, which renders the valve inoperable. In this research, a non-destructive fault simulator was developed which induced artificial friction faults in the PSV. The PSV consisted of two solenoids on the opposite sides of the valve spool by virtue of which, bi-directional position control could be achieved.The PSV with the spool and one of the solenoids was used as the system in which the faults were simulated, and the second solenoid was used an a fault simulator for inducing the desired friction characteristics in the system. The friction characteristics induced in the valve were similar to those in the classical friction curve, i.e., stiction at low velocities and Coulomb and viscous friction at higher velocities. By employing a closed loop position control scheme, one of the solenoids was used to generate a linearly increasing velocity profile by virtue of which the desired friction characteristics could be induced in different velocity regimes. The other solenoid was used to generate the desired friction force. A closed loop force control strategy, which used the feedback from a force transducer, allowed for the accurate control of the friction characteristics. stiction was induced at low velocities by passing the required current in both the solenoids that resulted in no net force on the valve spool. Due to the absence of any driving force the spool was stalled at the desired location, thus achieving the same effect of stiction at low velocities. The coulomb and viscous friction were induced at higher velocities by employing an algorithm which was a function of the spool velocity. Different magnitudes of static, coulomb and viscous friction were induced to achieve the friction characteristics represented by the classical friction curve. Since the change in force characteristics of the valve results in a corresponding change in the current drawn by the position control solenoid, a rudimentary CMS for monitoring the current characteristics is presented. Based on the experimental results and validation using the CMS it was concluded that the fault simulator was able to accurately produce the desired frictional loading on the valve spool and was able to do so with a high degree of repeatability.

Proportional Solenoid Valves (PSV) have been successfully used in the hydraulic industry for many years due to the benefits associated with higher accuracy compared to on/off solenoid valves, and the robustness and cost compared to servo valves. Because the PSV plays an important role in the performance of a hydraulic system, a technique commonly referred to as Condition Monitoring Scheme (CMS) has been used extensively to monitor the progress of faults in the PSV. But before any CMS can be implemented on a system, it needs to be thoroughly tested for its reliability of fault detection since, a failure of the CMS to detect any potential fault can be economically disastrous, and dangerous in terms of the safety of personnel. The motivation of this research was to develop a fault simulator which could reliably and repeatedly induce user defined faults in the PSV and thereby aid in testing the efficacy of the CMS for monitoring such simulated faults.<p>Industry research has revealed that the most common mode of failure in spool valves is an increase in the friction between the spool and valve, due to wear, contamination and dirt, which renders the valve inoperable. In this research, a non-destructive fault simulator was developed which induced artificial friction faults in the PSV. The PSV consisted of two solenoids on the opposite sides of the valve spool by virtue of which, bi-directional position control could be achieved. The PSV with the spool and one of the solenoids was used as the system in which the faults were simulated, and the second solenoid was used an a fault simulator for inducing the desired friction characteristics in the system. <p>The friction characteristics induced in the valve were similar to those in the classical friction curve, i.e., stiction at low velocities and Coulomb and viscous friction at higher velocities. By employing a closed loop position control scheme, one of the solenoids was used to generate a linearly increasing velocity profile by virtue of which the desired friction characteristics could be induced in different velocity regimes. The other solenoid was used to generate the desired friction force. A closed loop force control strategy, which used the feedback from a force transducer, allowed for the accurate control of the friction characteristics. stiction was induced at low velocities by passing the required current in both the solenoids that resulted in no net force on the valve spool. Due to the absence of any driving force the spool was stalled at the desired location, thus achieving the same effect of stiction at low velocities. The coulomb and viscous friction were induced at higher velocities by employing an algorithm which was a function of the spool velocity. Different magnitudes of static, coulomb and viscous friction were induced to achieve the friction characteristics represented by the classical friction curve. Since the change in force characteristics of the valve results in a corresponding change in the current drawn by the position control solenoid, a rudimentary CMS for monitoring the current characteristics is presented. Based on the experimental results and validation using the CMS it was concluded that the fault simulator was able to accurately produce the desired frictional loading on the valve spool and was able to do so with a high degree of repeatability. Proportional Solenoid Valves (PSV) have been successfully used in the hydraulic industry for many years due to the benefits associated with higher accuracy compared to on/off solenoid valves, and the robustness and cost compared to servo valves. Because the PSV plays an important role in the performance of a hydraulic system, a technique commonly referred to as Condition Monitoring Scheme (CMS) has been used extensively to monitor the progress of faults in the PSV. But before any CMS can be implemented on a system, it needs to be thoroughly tested for its reliability of fault detection since, a failure of the CMS to detect any potential fault can be economically disastrous, and dangerous in terms of the safety of personnel. The motivation of this research was to develop a fault simulator which could reliably and repeatedly induce user defined faults in the PSV and thereby aid in testing the efficacy of the CMS for monitoring such simulated faults. Industry research has revealed that the most common mode of failure in spool valves is an increase in the friction between the spool and valve, due to wear, contamination and dirt, which renders the valve inoperable. In this research, a non-destructive fault simulator was developed which induced artificial friction faults in the PSV. The PSV consisted of two solenoids on the opposite sides of the valve spool by virtue of which, bi-directional position control could be achieved.The PSV with the spool and one of the solenoids was used as the system in which the faults were simulated, and the second solenoid was used an a fault simulator for inducing the desired friction characteristics in the system. The friction characteristics induced in the valve were similar to those in the classical friction curve, i.e., stiction at low velocities and Coulomb and viscous friction at higher velocities. By employing a closed loop position control scheme, one of the solenoids was used to generate a linearly increasing velocity profile by virtue of which the desired friction characteristics could be induced in different velocity regimes. The other solenoid was used to generate the desired friction force. A closed loop force control strategy, which used the feedback from a force transducer, allowed for the accurate control of the friction characteristics. stiction was induced at low velocities by passing the required current in both the solenoids that resulted in no net force on the valve spool. Due to the absence of any driving force the spool was stalled at the desired location, thus achieving the same effect of stiction at low velocities. The coulomb and viscous friction were induced at higher velocities by employing an algorithm which was a function of the spool velocity. Different magnitudes of static, coulomb and viscous friction were induced to achieve the friction characteristics represented by the classical friction curve. Since the change in force characteristics of the valve results in a corresponding change in the current drawn by the position control solenoid, a rudimentary CMS for monitoring the current characteristics is presented. Based on the experimental results and validation using the CMS it was concluded that the fault simulator was able to accurately produce the desired frictional loading on the valve spool and was able to do so with a high degree of repeatability.

No description available.

<p>To control the exhaust gas recirculation (EGR) and the exhaust brake, the position of a butterfly valve connected to a piston inside a pneumatic cylinder is controlled by altering the pressure inside the cylinder. This thesis evaluates the possibility to do this with pulse width modulation (PWM) controlled On/Off valves. The whole electro-pneumatic actuator system is built out of two On/Off valves and a cylinder.</p><p>A mathematical model of the system is constructed. The complete system model on state space form consists of nine states and is nonlinear. The model captures the dynamics of the system. The statics of the system is not captured as accurately. The model is still good enough to be used as aid when developing control strategies, since position feedback is available.</p><p>Automatic control strategies for the system are first developed and tested in simulation. The first approach is PID control. Because of the nonlinear properties of the system the results from a PID with a constant proportional part is unsatisfactory. To cope with the nonlinearities, a fuzzy controller is constructed; the results prove somewhat better, but not as good as expected due to implementation difficulties.</p><p>In a test bench the system is controlled by a P controller with feedforward from position. The feedforward strongly reduces the nonlinear behavior of the system. With this implementation the results that were hoped for with the fuzzy controller are reached.</p>

To control the exhaust gas recirculation (EGR) and the exhaust brake, the position of a butterfly valve connected to a piston inside a pneumatic cylinder is controlled by altering the pressure inside the cylinder. This thesis evaluates the possibility to do this with pulse width modulation (PWM) controlled On/Off valves. The whole electro-pneumatic actuator system is built out of two On/Off valves and a cylinder. A mathematical model of the system is constructed. The complete system model on state space form consists of nine states and is nonlinear. The model captures the dynamics of the system. The statics of the system is not captured as accurately. The model is still good enough to be used as aid when developing control strategies, since position feedback is available. Automatic control strategies for the system are first developed and tested in simulation. The first approach is PID control. Because of the nonlinear properties of the system the results from a PID with a constant proportional part is unsatisfactory. To cope with the nonlinearities, a fuzzy controller is constructed; the results prove somewhat better, but not as good as expected due to implementation difficulties. In a test bench the system is controlled by a P controller with feedforward from position. The feedforward strongly reduces the nonlinear behavior of the system. With this implementation the results that were hoped for with the fuzzy controller are reached.

This thesis deals with the determination of the position of the solenoid core in real time based on the measured current. The reference position of the current is used for feedback control of the solenoid. For this issue, software tool Matlab/Simulink was used. For current and temperature measurements, PCB circuits were created. The whole project was carried out on the dSPACE platform.

The presented innovative magnetic testing method utilises the fact, that each commercially available electromagnet can not only be used as an actuator, but also comprises internal sensor functions. This allows a huge application variety in the fields of non-destructive testing and condition monitoring of electromagnetic systems during production and within the application in the field.

This thesis deals with the determination of the position of the solenoid core in real time based on the measured current. The reference position of the current is used for feedback control of the solenoid. For this issue, software tool Matlab/Simulink was used. For current and temperature measurements, PCB circuits were created. The whole project was carried out on the dSPACE platform.

Bedbugs are insects which exclusively feed on the blood of humans and other large animals. Bedbug infestations are a growing problem in modern society and some of the current solutions involve humans acting as bait to lure the bedbugs out of their nests. Research indicates that bedbugs are attracted to, among other things, the increased levels of carbon dioxide (CO2) that humans emit. This project aimed to create a machine that was able to simulate human breathing to a point where it could be used as a human substitute to a human during treatment for bedbug infestations. The prototype was based on diaphragmatic breathing and a pump mechanism was built which breathes air in and out. The machine’s purpose was to manipulate the air by adding a specific amount of CO2 and humidity. To control the levels of CO2 and humidity, a control system was designed. The system was tested with the goal of being able to maintain a specified level of CO2 and humidity over a longer period of time. Tests found that CO2-levels were possible to regulate with relative ease, however the chosen components for the humidity-system was found to not be effective in regards of rapidly increasing the humidity to the levels that can be found in human exhaled air. / Vägglöss är en insekt som exklusivt livnär sig på blod från djur och människor. Vägglössangrepp är ett växande problem i samhället och vissa nuvarande lösningar involverar att en människa agerar lockbete för att locka ut vägglössen från sina gömställen. Forskningen pekar på att vägglöss attraheras av bland annat de ökade halterna av koldioxid (CO2) som utsöndras av människan. Detta projekts ändamål var att skapa en maskin som simulerar mänsklig utandning för att kunna användas som ett substitut för en människa under en behandling av ett vägglössangrepp. Prototypen har baserats på diafragmaandning och en pumpmekanism har byggts som andas in och ut luft. Maskinen ämnar manipulera den inandade luften med en önskad mängd CO2 och fukt. För att kontrollera de önskade nivåerna designades ett kontrollsystem. Detta har sedan testats med målet att kunna ha en önskad och stabil nivå av CO2 och fukt under en längre period. Tester fann att CO2-nivåerna gick att reglera med ett relativt enkelt kontrollsystem men att det valda luftfuktningssystemet inte var effektivt nog för att höja fuktnivån till den som återfinns i mänsklig utandningsluft.

No description available.