13-11-2012, 02:03 PM
crane controller
[attachment=39241]
The crane is controlled by remote control which is intercepted with a microcontroller, to which all the input information is given. It read and analyzes the formation of coding through data transmission lines to dual tone multi-frequency signal (DTMF) transceiver chip. The radio wave signal is demodulated and decoded by transceiver chip for emission. The MCU completes the command code from reception and recognition and then it sends the command-driven peripherals, process requirements to be completed by the lifting action.
The crane controller consists of three blocks 1) Analog to Digital Converter block 2) Pulse width modulator block 3) Control output circuitry block in ADC block I gave analog input voltage, two set point voltages and power voltage to determine the correct resolution for the closest digital out put, which is verified with microcontroller output utilizing LED.
In Micro controller function block
I supplied the input from digital out put of A-D converter block representing the value of analog speed reference input to the system. The limit Switch input to the system is also fed into this block. The out put of this block is given in two forms- pulse width and pulse polarity which controls the polarity of the systems square wave out put.
I tested the block in multiple ways; I tested the software portion where C program is used as driver for the function and as a simulator for a wide range of digital input. I plotted graph by taking values from the simulator out put. I tested the full range of analog inputs in small steps and verify that we output the correct duty cycle and polarity for each input. By using mechanical switch as input to the microcontroller I tested the limit switch and verified that closing each limits switch disables the output of appropriate polarity.
Experimental set up
The tunnel operates as open circuit, meaning air is drawn from the laboratory and exhausted outside the building. The laboratory tunnel incorporates a supersonic nozzle contour which has been designed using methods of characteristics. The nozzle coordinates that are listed include an empirical correction for boundary layer growth, which is an important factor at high speeds. The contoured tunnel floor is slotted and sealed to permit the insertion of a traversing Pitot tube. The roof of the test section is plane and corresponds to the centerline of a hypothetical symmetrical tunnel of twice the height. Air is sucked through the Laval nozzle of the tunnel depicted in Figs. 1 and 2, but several other methods of flow drive may be used.
The position of the flow intake valve (i.e. the percentage that the valve is open; 100% corresponding to fully open) is set through a computer-controlled DC gear-head motor. The position of the valve is measured using a rotary potentiometer that converts the valve position to a voltage that can be read by the DAQ board. Therefore, to move the valve to a desired position the software turns on the motor with a direction corresponding to opening or closing the valve, while simultaneously reading the valve potentiometer voltage. Once the voltage corresponding to the desired valve position is reached the software turns off the motor.
The pressure from the impact and static pressure probes is measured using pressure transducers that convert pressure values to a voltage that can be read by the DAQ board. Each pressure probe can also be connected to the Wallace & Tiernan dial gages through an array of computer-controlled solenoid valves.
Probe Manipulator
The position of the impact pressure probe (Pitot tube) in the tunnel test section is changed using a computer-controlled manipulation system that has 2 degrees of freedom, namely x (horizontal) and y (vertical) translation. The computer control system enables the experimenter to not only collect data more accurately, but also perform multiple tasks simultaneously.
Determination of Isentropic Flow Properties in Nozzles
A MATLAB file can be generated from the experiment user interface which computes the predicted values for M listed in Table 1, using the tabulated A/A* data from the same table. The Pitot tube measures the stagnation or total pressure behind the shock. In this diagram p1 corresponds to the static pressure in a plane which is tangent to the shock. The following expression, known as the Rayleigh Pitot Relation is usually solved recursively to obtain M once p1 and p02 are known.
Optical Methods for Gas Dynamic Analysis
Shock waves are thin (about 0.0001 cm) but special diagnostic techniques are available for visualizing the variations in fluid density which accompanies shock formation. The local change of refractive index—due to gas compression—interferes with the transmission of an illuminating beam, and this provides a visual manifestation of the shock Interferometers, Schlieren systems.
The Schlieren Method
The Schlieren apparatus for this experiment, shown schematically in Fig. 8, uses lenses. However, for larger systems with long focal lengths mirrors are customarily employed, since these are less expensive than lenses for comparable size and optical performance. In Fig. 8 a light source S is imaged by the lens L1 onto aperture A , which serves to define the source and eliminate any spurious light due to reflections from the source envelope. Lens L2 collimates the light which then passes through the test section and is focused by L3 in the plane of a knife edge KE.
The knife edge is adjusted so that in the absence of any disturbance in the test section it just occludes all the radiation that would normally pass to the viewing screen. A shock wave or similar perturbation of the fluid density in the test section may then cause light to pass around KE as explained in Fig. 7. If the location of the screen is chosen such that it displays a sharp image of the test section via L3 and the previous conditions have been met, then shock waves are readily observable.
Collect static and stagnation pressure data to compute the Mach number. The MATLAB® file generated by the interface can be used to compute both the theoretical and experimental Mach numbers for this experiment, but you need to complete collecting data for all tests before running the file.
[attachment=39241]
The crane is controlled by remote control which is intercepted with a microcontroller, to which all the input information is given. It read and analyzes the formation of coding through data transmission lines to dual tone multi-frequency signal (DTMF) transceiver chip. The radio wave signal is demodulated and decoded by transceiver chip for emission. The MCU completes the command code from reception and recognition and then it sends the command-driven peripherals, process requirements to be completed by the lifting action.
The crane controller consists of three blocks 1) Analog to Digital Converter block 2) Pulse width modulator block 3) Control output circuitry block in ADC block I gave analog input voltage, two set point voltages and power voltage to determine the correct resolution for the closest digital out put, which is verified with microcontroller output utilizing LED.
In Micro controller function block
I supplied the input from digital out put of A-D converter block representing the value of analog speed reference input to the system. The limit Switch input to the system is also fed into this block. The out put of this block is given in two forms- pulse width and pulse polarity which controls the polarity of the systems square wave out put.
I tested the block in multiple ways; I tested the software portion where C program is used as driver for the function and as a simulator for a wide range of digital input. I plotted graph by taking values from the simulator out put. I tested the full range of analog inputs in small steps and verify that we output the correct duty cycle and polarity for each input. By using mechanical switch as input to the microcontroller I tested the limit switch and verified that closing each limits switch disables the output of appropriate polarity.
Experimental set up
The tunnel operates as open circuit, meaning air is drawn from the laboratory and exhausted outside the building. The laboratory tunnel incorporates a supersonic nozzle contour which has been designed using methods of characteristics. The nozzle coordinates that are listed include an empirical correction for boundary layer growth, which is an important factor at high speeds. The contoured tunnel floor is slotted and sealed to permit the insertion of a traversing Pitot tube. The roof of the test section is plane and corresponds to the centerline of a hypothetical symmetrical tunnel of twice the height. Air is sucked through the Laval nozzle of the tunnel depicted in Figs. 1 and 2, but several other methods of flow drive may be used.
The position of the flow intake valve (i.e. the percentage that the valve is open; 100% corresponding to fully open) is set through a computer-controlled DC gear-head motor. The position of the valve is measured using a rotary potentiometer that converts the valve position to a voltage that can be read by the DAQ board. Therefore, to move the valve to a desired position the software turns on the motor with a direction corresponding to opening or closing the valve, while simultaneously reading the valve potentiometer voltage. Once the voltage corresponding to the desired valve position is reached the software turns off the motor.
The pressure from the impact and static pressure probes is measured using pressure transducers that convert pressure values to a voltage that can be read by the DAQ board. Each pressure probe can also be connected to the Wallace & Tiernan dial gages through an array of computer-controlled solenoid valves.
Probe Manipulator
The position of the impact pressure probe (Pitot tube) in the tunnel test section is changed using a computer-controlled manipulation system that has 2 degrees of freedom, namely x (horizontal) and y (vertical) translation. The computer control system enables the experimenter to not only collect data more accurately, but also perform multiple tasks simultaneously.
Determination of Isentropic Flow Properties in Nozzles
A MATLAB file can be generated from the experiment user interface which computes the predicted values for M listed in Table 1, using the tabulated A/A* data from the same table. The Pitot tube measures the stagnation or total pressure behind the shock. In this diagram p1 corresponds to the static pressure in a plane which is tangent to the shock. The following expression, known as the Rayleigh Pitot Relation is usually solved recursively to obtain M once p1 and p02 are known.
Optical Methods for Gas Dynamic Analysis
Shock waves are thin (about 0.0001 cm) but special diagnostic techniques are available for visualizing the variations in fluid density which accompanies shock formation. The local change of refractive index—due to gas compression—interferes with the transmission of an illuminating beam, and this provides a visual manifestation of the shock Interferometers, Schlieren systems.
The Schlieren Method
The Schlieren apparatus for this experiment, shown schematically in Fig. 8, uses lenses. However, for larger systems with long focal lengths mirrors are customarily employed, since these are less expensive than lenses for comparable size and optical performance. In Fig. 8 a light source S is imaged by the lens L1 onto aperture A , which serves to define the source and eliminate any spurious light due to reflections from the source envelope. Lens L2 collimates the light which then passes through the test section and is focused by L3 in the plane of a knife edge KE.
The knife edge is adjusted so that in the absence of any disturbance in the test section it just occludes all the radiation that would normally pass to the viewing screen. A shock wave or similar perturbation of the fluid density in the test section may then cause light to pass around KE as explained in Fig. 7. If the location of the screen is chosen such that it displays a sharp image of the test section via L3 and the previous conditions have been met, then shock waves are readily observable.
Collect static and stagnation pressure data to compute the Mach number. The MATLAB® file generated by the interface can be used to compute both the theoretical and experimental Mach numbers for this experiment, but you need to complete collecting data for all tests before running the file.