Rotational speed sensors

Similar to rotational-speed sensors, angle and linear position sensors can be found in a wide variety of applications and systems. Sensor requirements and associated techniques are as manifold as these applications. Some of the most important sensors measure... 

Figure 5.7.8 shows the layout of a rotational speed sensor that is designed as a gradiometer. The Wheatstone bridge is split into two half bridges, which are sepa-... 

The models where two or four batches of powders can be processed in the cylinders mounted on rotating plate were the workhorse instruments in many laboratories. The recent Pulverisette model 7 was designed with larger rotational speeds specially for processing of powders to nanometric-level size. The Fritsch model Pulverisette mills, models 4, 5, and 6, are compatible with an interesting reactor cylinder, in which the cover is equipped with pressure and temperature sensor and a small radiofrequency unit allows for wireless transfer of the sensors data to the receiver interfaced with computer. This GTP (temperature-pressure) system developed... 

Rotational-speed and phase sensors represent the largest market by unit of all sensor types. The most important applications are ... 

The total market for rotational-speed and phase sensors is estimated to be 310 million units in 2002, increasing to 390 million units in 2008, and representing a market value of more than 1600 million. The total market is almost saturated, so new sensor types will replace the older, passive technology. 

Active wheel-speed sensors have been available for years. New features in modem cars to enhance comfort require more information about the behavior of the car. One important piece of information is the rotational direction of the wheels, and hence the direction of the car. The Bosch DFlli was the first sensor to deliver this information, and it was used in the Bosch EHB system in 2001. The sensor transmits this additional information by modulation of the pulse width of the speed signal. The sensor contains three Hall elements two for speed measurement by the difference principle, and a third arranged in such a way that an addi-... 

Speed limits the ability to transduce applied force or torque for all measurement methods. Apart from electrical limits of filtering and signal conversion effects like material internal friction, skin effects and non-homogeneous material behavior will define speed limits. In most cases the rotational speed defines the principle of signal transmission. This is one of the reasons why torque sensors are still not used with automatic transmission. The input torque is calculated by the engine management [5],... 

Flow. Nonintrusive sensors that can be maintained at the process temperature are ideally suited to measure the flow rate of feed and product streams. Magnetic flow meters are suitable and inexpensive choice for aqueous streams. Organic streams with low dielectric constants require a vibrating tube mass flow meter to satisfy these criteria. Although commonly installed, flow meters that operate by inducing a pressure drop proportional to the flow rate present restrictions for solids accumulation that may alter the calibration. An alternative approach is to monitor the rotational speed of a positive displacement pump. Accuracy of this method is subject to wear and tolerances in the pump. 

The shaft was connected to a variable speed electric motor via a flexible coupling. Rotational speeds were chosen to give a certain shear rate and detected by an optical sensor. The infrared polarizer in die radiation path downstream from the window was inserted parallel to the shaft which applied shear on the lubricant layers. Two directions were distinguished parallel (0 ) and perpendicular (90 ) to flow of lubricant in a surface parallel to the shaft. Three types of spectra were obtained, one unpolarized and two polarized. 

Rotation Speed. Most often, FSW and its variants use motors with internal control through drives. The motor speed is almost always controlled and is often monitored via output from motor drives. Separate sensors are not required. 

Various visual clues including head movement, eye gaze direction and ocular measures are computed from Kinect sensor data. The following features are extracted mean value of head positions in 3D coordinate system of Kinect sensor within a measurement time frame mean value of head orientation measures, i.e., pitch, yaw and roU frequency domain analysis for head translation and rotation on three axes and its Euchdean norm based on FFT head translation speed and head rotation speed mean value of eyebrow positions relative to the respective eyes within a measurement time frame mean value of eye blink frequency and blink duration within a measurement time frame. 

During calibration, the shear stress sensor is mounted on the stationary plate at various radial positions with different gap size and rotational speed to achieve a wide range of shear stress values for static calibration. 

Probably the most common experiment carried out on aqueous systems containing synthetic polymers is that in which the shear stress is increased from zero to a maximum before being reduced back to zero over a time period of several minutes or more. The rotational speed of the sensor is recorded in line with the applied stress throughout the course of the experiment, so that shear rate data can be calculated. A plot of shear stress versus shear rate obtained in this way is often referred to as a flow curve as shown earlier in Figure 3.8. As already discussed, viscosity equals shear stress divided by shear rate. A viscosity profile is shovm by the viscosity value versus shear rate. 

A magnetic sensor indicated shaft orientation and provided a pulse for an accurate rotational speed indicator. 

The front panel of the casing of the instrument contains the adjustment and control units (control switches for the UV lamps (254 nm and 366 nm), timing unit, and temperature), with a keyboard of the sensor type, as well as the power switch for the instrument, and the switch for the nitrogen overpressure with a manometer (0-2.5 bar). The rotation speed may be varied between 80 and 2000 rpm in steps of 10 and 100 rpm. 

In this experiment, we use a simple controller program, where the rotation speed of wheels has only two values, and la- Moreover we assume that sensors only tell white and black colors on the track. In other words, the values of si and sr are determined by only the position of the line tracing robot. On the other hand, we model the delay of sensors and actuators. Concretely, we have parameters ds, da, and dt for delay between the time when program senses color and the time when the sensors obtain the values of colors, delay between the time when program issues a command and the time when the motor reacts, and sleeping time for next sense-act loop, respectively. This modeling represents real behaviors of a line tracing robot. 

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