A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification
Inspired by improving the adaptive capability of the robot to external impacts or shocks, the adjustable stiffness behavior in joints is investigated to ensure conformity with the safety index. This paper proposes a new soft actuation unit, namely Adjustable Stiffness Rotary Actuator (ASRA), induced...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Actuators |
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| Online Access: | https://www.mdpi.com/2076-0825/9/4/141 |
| _version_ | 1797544257232306176 |
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| author | Cong Phat Vo Van Du Phan Thanh Ha Nguyen Kyoung Kwan Ahn |
| author_facet | Cong Phat Vo Van Du Phan Thanh Ha Nguyen Kyoung Kwan Ahn |
| author_sort | Cong Phat Vo |
| collection | DOAJ |
| description | Inspired by improving the adaptive capability of the robot to external impacts or shocks, the adjustable stiffness behavior in joints is investigated to ensure conformity with the safety index. This paper proposes a new soft actuation unit, namely Adjustable Stiffness Rotary Actuator (ASRA), induced by a novel optimization of the elastic energy in an adjusting stiffness mechanism. Specifically, a stiffness transmission is configured by three pairs of antagonistically linear springs with linkage bars. The rotational disk and link bars assist the simplified stiffness control based on a linear transmission. To enhance the elastic energy efficiency, the force compressions of the linear springs are set to be perpendicular to the three-spoke output element, i.e., the output link direction. Besides, the ASRA model is also formed to investigate the theoretical capabilities of the stiffness output and passive energy. As a simulated result, a high passive energy storage ability can be achieved. Then, several experimental scenarios are performed with integral sliding mode controllers to verify the physical characteristics of the ASRA. As trial results, the fast transient response and high accuracy of both the position and stiffness tracking tests are expressed, in turn, independent and simultaneous control cases. Moreover, the real output torque is measured to investigate its reflecting stiffness. |
| first_indexed | 2024-03-10T13:57:01Z |
| format | Article |
| id | doaj.art-4cfe1ea52d6041209eb7ef0a687dd350 |
| institution | Directory Open Access Journal |
| issn | 2076-0825 |
| language | English |
| last_indexed | 2024-03-10T13:57:01Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Actuators |
| spelling | doaj.art-4cfe1ea52d6041209eb7ef0a687dd3502023-11-21T01:28:38ZengMDPI AGActuators2076-08252020-12-019414110.3390/act9040141A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental VerificationCong Phat Vo0Van Du Phan1Thanh Ha Nguyen2Kyoung Kwan Ahn3School of Mechanical and Automotive Engineering, University of Ulsan, Ulsan 44610, KoreaSchool of Mechanical and Automotive Engineering, University of Ulsan, Ulsan 44610, KoreaSchool of Mechanical and Automotive Engineering, University of Ulsan, Ulsan 44610, KoreaSchool of Mechanical and Automotive Engineering, University of Ulsan, Ulsan 44610, KoreaInspired by improving the adaptive capability of the robot to external impacts or shocks, the adjustable stiffness behavior in joints is investigated to ensure conformity with the safety index. This paper proposes a new soft actuation unit, namely Adjustable Stiffness Rotary Actuator (ASRA), induced by a novel optimization of the elastic energy in an adjusting stiffness mechanism. Specifically, a stiffness transmission is configured by three pairs of antagonistically linear springs with linkage bars. The rotational disk and link bars assist the simplified stiffness control based on a linear transmission. To enhance the elastic energy efficiency, the force compressions of the linear springs are set to be perpendicular to the three-spoke output element, i.e., the output link direction. Besides, the ASRA model is also formed to investigate the theoretical capabilities of the stiffness output and passive energy. As a simulated result, a high passive energy storage ability can be achieved. Then, several experimental scenarios are performed with integral sliding mode controllers to verify the physical characteristics of the ASRA. As trial results, the fast transient response and high accuracy of both the position and stiffness tracking tests are expressed, in turn, independent and simultaneous control cases. Moreover, the real output torque is measured to investigate its reflecting stiffness.https://www.mdpi.com/2076-0825/9/4/141Adjustable Stiffness Rotary Actuatorvariable stiffness transmission mechanismenergy efficiency |
| spellingShingle | Cong Phat Vo Van Du Phan Thanh Ha Nguyen Kyoung Kwan Ahn A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification Actuators Adjustable Stiffness Rotary Actuator variable stiffness transmission mechanism energy efficiency |
| title | A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification |
| title_full | A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification |
| title_fullStr | A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification |
| title_full_unstemmed | A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification |
| title_short | A Compact Adjustable Stiffness Rotary Actuator Based on Linear Springs: Working Principle, Design, and Experimental Verification |
| title_sort | compact adjustable stiffness rotary actuator based on linear springs working principle design and experimental verification |
| topic | Adjustable Stiffness Rotary Actuator variable stiffness transmission mechanism energy efficiency |
| url | https://www.mdpi.com/2076-0825/9/4/141 |
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