KEYWORDS: Phase measurement, Field effect transistors, Bridges, Digital electronics, Field programmable gate arrays, Computer programming, Signal detection, Logic, Digital electronic circuits, Sensors
The induced electromotive force of traditional motor measurement usually uses another motor to connect the tested
motor with the drive shaft to measure its speed and obtain Ke value of induced electromotive force of the tested motor. If the tested motor is not suitable for connection to the connect coupling because of the shape or volume of the rotor, it is difficult to measure the Ke values of the tested motor. So some scholars have proposed two-phase motor which drives the three-phase motor, and gain the measurement method of Ke from the third phase in a few years ago. The mainly way is using the digital logic circuits to redefine the truth table by entering the signals to the motor driver chip from the three Hall sensors. So it can still maintain a positive torque above 0 even if used the two-phase driver and the motor can be rotated by the two-phase driver. But the drawback is that it can only be measured the fixed Ke value at the same phase. And it has to redefine the truth table to measure the values of the other two phase. This paper provides a new measurement method that made the motor speed accelerate to the measured speed at the beginning and measuring the value of third phases while the rotation is maintained by the other two-phase. The advantage is that it can change the phase of measurement, so it can easily measure the Ke value. And the most of digital components which including processor, keyboard decoder and frequency counter etc can be achieved in FPGA by using SOPC method. It can significantly reduce the complexity of circuit and increase system reliability degree.
The measurement of micro gears with a touch-trigger probe will be introduced in this paper. Due to the small size and complex geometry of micro gears, it is difficult to measure them by traditional instruments like coordinate measuring machines (CMM) or laser displacement sensors. This study focuses on this topic and proposes an approach to measure the three dimensional profile of micro gears. The methodology is based on coordinate measurement. A special touch-trigger probe which detects the moment of contact is employed in the measuring system. The diameter of the probe tip is smaller than 2µm and therefore small enough for measuring micro structures. All the calibration and error compensation for the measuring system are discussed in the view of micro metrology. The comparison of measured profiles from both coordinate and image measurement is discussed. Results of experiments show that the proposed approach is worth of further development in the future.
This paper presents the design principle and applications of a innovative dual-axis optoelectronic level. A commercially
available DVD pickup head is adopted as the angle sensor in association with the double-layer pendulum mechanism for
dual-axis swings. A mass-damping system is analyzed to model the mechanical dynamics. Measured angles of both axes
are processed by a microprocessor and displayed on a LCD or exported to an external PC. Compared with a triple-beam
laser angular interferometer, the error of the dual-axis optoelectronic level is better than ±0.5 arc-seconds in the
measuring range of ±20 arc-seconds, and the settling time is within 0.5 sec. Two experimental results show the
consistency with a Renishaw interfereometer and its practical use in industry.
The recent fast development of multifunctional portable electronic devices results in the obvious requirement of micro
mechanical components. Due to the popular application of the micro actuators and the micro gearboxes, micro gears
become the frequently used micro mechanical component in a small device such as small intelligent robots or dental
surgical devices. Metal Industries Research & Development Centre (MIRDC) has successfully developed a small speed
reducer that comprises several micro planetary gear trains. The module of this micro planetary gear train is 0.12mm.
Since all gears are small, no commercial instrument is available for inspection. How to evaluate the manufacturing
quality of micro gears becomes an important issue. This study focuses on the double flank gear rolling test and a
specialized apparatus is built referring to the testing requirements in the international standards. The center distance
variation during the rolling test is recorded and two indices, the total radial composite deviation and the maximum
tooth-to-tooth radial composite deviation, are calculated to evaluate the accuracy grade of the micro gears. Experimental
results show that the accuracy of the micro gear made by the cold forging process conforms to grade 7 defined in the ISO
1328-2 while grade 2 is achieved if the JGMA 116-02 is specified.
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