Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes
In this paper, a method to control one degree of freedom lightweight flexible manipulators is investigated. These robots have a single low-frequency and high amplitude vibration mode. They hold actuators with high friction, and sensors which are often strain gauges with offset and high-frequency noi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-11-01
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| Series: | Actuators |
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| Online Access: | https://www.mdpi.com/2076-0825/10/12/317 |
| _version_ | 1797507066763411456 |
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| author | Saddam Gharab Selma Benftima Vicente Feliu Batlle |
| author_facet | Saddam Gharab Selma Benftima Vicente Feliu Batlle |
| author_sort | Saddam Gharab |
| collection | DOAJ |
| description | In this paper, a method to control one degree of freedom lightweight flexible manipulators is investigated. These robots have a single low-frequency and high amplitude vibration mode. They hold actuators with high friction, and sensors which are often strain gauges with offset and high-frequency noise. These problems reduce the motion’s performance and the precision of the robot tip positioning. Moreover, since the carried payload changes in the different tasks, that vibration frequency also changes producing underdamped or even unstable time responses of the closed-loop control system. The actuator friction effect is removed by using a robust two degrees of freedom <i>PID</i> control system which feeds back the actuator position. This is called the inner loop. After, an outer loop is closed that removes the link vibrations and is designed based on the combination of the singular perturbation theory and the input-state linearization technique. A new controller is proposed for this outer loop that: (1) removes the strain gauge offset effects, (2) reduces the risk of saturating the actuator due to the high-frequency noise of strain gauges and (3) achieves high robustness to a change in the payload mass. This last feature prompted us to use a fractional-order <i>PD</i> controller. A procedure for tuning this controller is also proposed. Simulated and experimental results are presented that show that its performance overcomes those of <i>PD</i> controllers, which are the controllers usually employed in the input-state linearization of second-order systems. |
| first_indexed | 2024-03-10T04:42:23Z |
| format | Article |
| id | doaj.art-47d79872933e4c1887f3641c042e0989 |
| institution | Directory Open Access Journal |
| issn | 2076-0825 |
| language | English |
| last_indexed | 2024-03-10T04:42:23Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Actuators |
| spelling | doaj.art-47d79872933e4c1887f3641c042e09892023-11-23T03:16:31ZengMDPI AGActuators2076-08252021-11-01101231710.3390/act10120317Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload ChangesSaddam Gharab0Selma Benftima1Vicente Feliu Batlle2Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, SpainInstituto de Investigaciones Energéticas y Aplicaciones Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, SpainEscuela Técnica Superior de Ingeniería Industrial de Ciudad Real, Universidad de Castilla-La Mancha, 13071 Ciudad Real, SpainIn this paper, a method to control one degree of freedom lightweight flexible manipulators is investigated. These robots have a single low-frequency and high amplitude vibration mode. They hold actuators with high friction, and sensors which are often strain gauges with offset and high-frequency noise. These problems reduce the motion’s performance and the precision of the robot tip positioning. Moreover, since the carried payload changes in the different tasks, that vibration frequency also changes producing underdamped or even unstable time responses of the closed-loop control system. The actuator friction effect is removed by using a robust two degrees of freedom <i>PID</i> control system which feeds back the actuator position. This is called the inner loop. After, an outer loop is closed that removes the link vibrations and is designed based on the combination of the singular perturbation theory and the input-state linearization technique. A new controller is proposed for this outer loop that: (1) removes the strain gauge offset effects, (2) reduces the risk of saturating the actuator due to the high-frequency noise of strain gauges and (3) achieves high robustness to a change in the payload mass. This last feature prompted us to use a fractional-order <i>PD</i> controller. A procedure for tuning this controller is also proposed. Simulated and experimental results are presented that show that its performance overcomes those of <i>PD</i> controllers, which are the controllers usually employed in the input-state linearization of second-order systems.https://www.mdpi.com/2076-0825/10/12/317flexible links robotfractional order controlrobust controlsensor offsethigh-frequency noise |
| spellingShingle | Saddam Gharab Selma Benftima Vicente Feliu Batlle Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes Actuators flexible links robot fractional order control robust control sensor offset high-frequency noise |
| title | Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes |
| title_full | Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes |
| title_fullStr | Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes |
| title_full_unstemmed | Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes |
| title_short | Fractional Control of a Lightweight Single Link Flexible Robot Robust to Strain Gauge Sensor Disturbances and Payload Changes |
| title_sort | fractional control of a lightweight single link flexible robot robust to strain gauge sensor disturbances and payload changes |
| topic | flexible links robot fractional order control robust control sensor offset high-frequency noise |
| url | https://www.mdpi.com/2076-0825/10/12/317 |
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