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Abstract

The ergodic channel capacity of wireless optical multiple-input multiple-output (MIMO) system with pulse position modulation (PPM) is investigated. The combined effects of atmospheric turbulence, atmospheric attenuation, pointing error and channel spatial correlation are taken into consideration. The expression of ergodic channel capacity is derived, and is further performed by Wilkinson approximation method for simplicity. The simulation results indicated that the strong spatial correlation has the greatest influence on the ergodic channel capacity, followed by pointing errors and atmospheric turbulence. Moreover, the ergodic channel capacity growth brought by space diversity only performs well under independent and weakly correlated channels. Properly increasing the size and spacing of the receiving apertures is an effective means of effectively increasing the ergodic channel capacity.
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Bibliography

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Authors and Affiliations

Minghua Cao
1
Yue Zhang
1
Zhongjiang Kang
1
Huiqin Wang
1

  1. School of Computer and Communication, Lanzhou University of Technology, Lanzhou, China
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Abstract

While cycloid pin-wheel precision reducers (referred to as RV reducers) are widely used in industrial robots, a widely accepted design standard or verification method of their test platforms is not available. In this study, a comprehensive sliding-separation test platform of RV reducers was developed. The test platform can test various measurement items such as transmission error, static measurement of lost motion, dynamic measurement of lost motion, torsional rigidity, no-load running torque, starting torque, backdriving torque, and transmission efficiency of the RV reducer for robots. The principle and method of dynamic measurement of lost motion tests based on the two-way transmission error method were studied and this test function was successfully integrated with the comprehensive test platform in order to increase the test items of the dynamic performance parameters of RV reducers. The measurement results of the no-load running torque of the RV reducer were consistent with the Stribeck curve. Based on the concept of optimal measurement speed, a decomposition test method of the geometric component of the dynamic measurement of lost motion and the elastic component of the dynamic measurement of lost motion was proposed in the dynamic measurement test of lost motion. Through precision calibration, function test and repeatability test, the results were compared with the data of enterprise’s samples. The consistent results have proved that the test platform met engineering requirements and measurement accuracy requirements. Based on the new test principle, the developed platform can test more parameters of RV reducers with high precision and display the comprehensive test performance.
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Authors and Affiliations

Huijun Yue
1
Xiangkai Wu
1
Zhaoyao Shi
1
Yue Zhang
1
Yong Ye
1
Lintao Zhang
1
Ying Fu
1

  1. Beijing University of Technology, Beijing Engineering Research Center of Precision Measurement Technology and Instruments, 100, Ping Le Yuan, Chaoyang District, Beijing 100124, China

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