Magnetorheological(MR) cell with multi-coil was designed to enlarge the range of controllable transmission torque by increasing the effective length. Individual input current was proposed to maximize its potential for...Magnetorheological(MR) cell with multi-coil was designed to enlarge the range of controllable transmission torque by increasing the effective length. Individual input current was proposed to maximize its potential for reducing power consumption and generating large yield stress. Finite element analysis was performed to analyze magnetic field distribution, based on which a prototype MR cell was fabricated and tested to investigate the performance of various combinations of individual input currents. A good correlation was identified between experimental results and FEA predications. The results show that the power consumption can be reduced to 42.4%, maintaining large transmission torque, by distributing the total current(2 A) to three individual magnetic coils. In addition, optimal results of four input currents considering a multi-objective function are obtained by changing the weighting factor λ. The advantage of this design, such as lower power consumption and more control flexibility, makes it more competitive in engineering applications that require large energy consumption.展开更多
<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes...<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes more greenhouse effects than carbon dioxide so a methane monitoring system is required to warn its release from gas emitting environments. The low explosive limit of methane is 5% in ambient air, so gas leakage is dangerous and can produce explosions. An entire head monitoring system was built around a MQ-4 methane gas sensor as it is cheap and reliable. The design proves to be flexible enough as it can measure CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> emissions in ducts, CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in landfills at different depths and even in cattle barns. The measuring system head consists of a suction pump, solenoids, and a methane sensor. Measurements are taken 13 seconds after methane gas sucking. </span><span style="font-family:Verdana;">A timing of 100 seconds is required for purging the chamber before the</span><span style="font-family:Verdana;"> second solenoid is turned-on. Devices temperature during operation was sampled with a thermal Flir-One camera and solenoid coil temperature was of 24.9</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="white-space:nowrap;">˚</span>C </span><span style="font-family:Verdana;">after a continuous operation of 30 seconds. As hoses for emission sampling</span><span style="font-family:Verdana;"> become larger time for sampling increases as well as energy consumption.</span></span>展开更多
基金Projects(51175265,51305207)supported by the National Natural Science Foundation of China
文摘Magnetorheological(MR) cell with multi-coil was designed to enlarge the range of controllable transmission torque by increasing the effective length. Individual input current was proposed to maximize its potential for reducing power consumption and generating large yield stress. Finite element analysis was performed to analyze magnetic field distribution, based on which a prototype MR cell was fabricated and tested to investigate the performance of various combinations of individual input currents. A good correlation was identified between experimental results and FEA predications. The results show that the power consumption can be reduced to 42.4%, maintaining large transmission torque, by distributing the total current(2 A) to three individual magnetic coils. In addition, optimal results of four input currents considering a multi-objective function are obtained by changing the weighting factor λ. The advantage of this design, such as lower power consumption and more control flexibility, makes it more competitive in engineering applications that require large energy consumption.
文摘<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane is released from waste disposal areas as a result from anaerobic decay of food. Methane causes more greenhouse effects than carbon dioxide so a methane monitoring system is required to warn its release from gas emitting environments. The low explosive limit of methane is 5% in ambient air, so gas leakage is dangerous and can produce explosions. An entire head monitoring system was built around a MQ-4 methane gas sensor as it is cheap and reliable. The design proves to be flexible enough as it can measure CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> emissions in ducts, CH</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in landfills at different depths and even in cattle barns. The measuring system head consists of a suction pump, solenoids, and a methane sensor. Measurements are taken 13 seconds after methane gas sucking. </span><span style="font-family:Verdana;">A timing of 100 seconds is required for purging the chamber before the</span><span style="font-family:Verdana;"> second solenoid is turned-on. Devices temperature during operation was sampled with a thermal Flir-One camera and solenoid coil temperature was of 24.9</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="white-space:nowrap;">˚</span>C </span><span style="font-family:Verdana;">after a continuous operation of 30 seconds. As hoses for emission sampling</span><span style="font-family:Verdana;"> become larger time for sampling increases as well as energy consumption.</span></span>
