A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors
Precision spherical joint is a spherical motion pair that can realize rotation with three degrees of freedom. This joint is widely used in robots, parallel mechanisms, and high-end medical equipment, as well as in aerospace and other fields. However, the rotation orientation and angle cannot be dete...
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| Format: | Article |
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MDPI AG
2020-07-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/20/14/4020 |
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| author | Penghao Hu Linchao Zhao Chuxin Tang Shanlin Liu Xueming Dang Yi Hu |
| author_facet | Penghao Hu Linchao Zhao Chuxin Tang Shanlin Liu Xueming Dang Yi Hu |
| author_sort | Penghao Hu |
| collection | DOAJ |
| description | Precision spherical joint is a spherical motion pair that can realize rotation with three degrees of freedom. This joint is widely used in robots, parallel mechanisms, and high-end medical equipment, as well as in aerospace and other fields. However, the rotation orientation and angle cannot be determined when the joint is in passive motion. The real-time determination of the rotation orientation and angle is crucial to the improvement of the motion control accuracy of the equipment where the joint is installed in. In this study, a new measurement method that utilizes eddy current sensors is proposed to identify the special features of the joint ball and realize angle measurements indirectly. The basic idea is to manufacture the specific shape features on the ball without affecting its movement accuracy and mechanical performance. An eddy current sensor array is distributed in the ball socket. When the ball head rotates, the features on the ball opposite to the sensor, as well as the output signal of every eddy current sensor, change. The measurement model that establishes the relationship between the output signal of the eddy current sensor array and the rotation direction and angle of the ball head is constructed by learning and training an artificial neural network. A prototype is developed using the proposed scheme, and the model simulation and feasibility experiment are subsequently performed. Results show that the root mean square angular error of a single axis within a range of ±14° is approximately 20 min, which suggests the feasibility of the proposed method. |
| first_indexed | 2024-03-10T18:21:31Z |
| format | Article |
| id | doaj.art-0124ab42768141bfb005af871aa76791 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T18:21:31Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-0124ab42768141bfb005af871aa767912023-11-20T07:17:30ZengMDPI AGSensors1424-82202020-07-012014402010.3390/s20144020A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current SensorsPenghao Hu0Linchao Zhao1Chuxin Tang2Shanlin Liu3Xueming Dang4Yi Hu5School of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaSchool of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaSchool of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaSchool of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaSchool of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaSchool of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, ChinaPrecision spherical joint is a spherical motion pair that can realize rotation with three degrees of freedom. This joint is widely used in robots, parallel mechanisms, and high-end medical equipment, as well as in aerospace and other fields. However, the rotation orientation and angle cannot be determined when the joint is in passive motion. The real-time determination of the rotation orientation and angle is crucial to the improvement of the motion control accuracy of the equipment where the joint is installed in. In this study, a new measurement method that utilizes eddy current sensors is proposed to identify the special features of the joint ball and realize angle measurements indirectly. The basic idea is to manufacture the specific shape features on the ball without affecting its movement accuracy and mechanical performance. An eddy current sensor array is distributed in the ball socket. When the ball head rotates, the features on the ball opposite to the sensor, as well as the output signal of every eddy current sensor, change. The measurement model that establishes the relationship between the output signal of the eddy current sensor array and the rotation direction and angle of the ball head is constructed by learning and training an artificial neural network. A prototype is developed using the proposed scheme, and the model simulation and feasibility experiment are subsequently performed. Results show that the root mean square angular error of a single axis within a range of ±14° is approximately 20 min, which suggests the feasibility of the proposed method.https://www.mdpi.com/1424-8220/20/14/4020spherical jointeddy current sensorGRNN algorithmangle measurement |
| spellingShingle | Penghao Hu Linchao Zhao Chuxin Tang Shanlin Liu Xueming Dang Yi Hu A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors Sensors spherical joint eddy current sensor GRNN algorithm angle measurement |
| title | A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors |
| title_full | A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors |
| title_fullStr | A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors |
| title_full_unstemmed | A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors |
| title_short | A New Method for Measuring the Rotational Angles of a Precision Spherical Joint Using Eddy Current Sensors |
| title_sort | new method for measuring the rotational angles of a precision spherical joint using eddy current sensors |
| topic | spherical joint eddy current sensor GRNN algorithm angle measurement |
| url | https://www.mdpi.com/1424-8220/20/14/4020 |
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