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Integrated DOB-Based Approach For Admittance Control of An Industrial Robot |
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Kangwagye Samuel(DGIST, Korea), Kevin Haninger(Fraunhofer IPK, Germany), Sehoon Oh(DGIST, Korea) |
| Admittance control can improve robot performance and robustness in interactive tasks, but is still limited by stability when implemented on low-admittance hardware. To improve accuracy of rendered dynamics and reduce contact forces, a novel integrated disturbance observer-based admittance control method which is implemented on a position/velocity-controlled industrial robot in task space is proposed. The multisensor information is integrated to estimate and cancel the disturbances, outside the position/velocity control loop, all in task space. Experiments on the actual robot show that the proposed method is able to improve accuracy and reduce contact forces even at higher admittance. |
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Intelligent Lower Limb Blood Circulation System for Long-Sitting People |
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Donghyun Kwon, Hyeoncheol Kim, Jungsu Choi(Yeungnam University, Korea) |
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Sedentary lifestyles have led to health issues due to poor lower limb venous circulation from prolonged sitting. While existing devices aiming to improve this are bulky and often ineffective, the paper introduces "Healthy-CAL," a compact calf stimulation device. Utilizing a Semi-Auto-Locking mechanism, it offers an enhanced operating range for better circulation. Additionally, its Limit Angle Recognition Algorithm ensures tailored ankle exercises by detecting the user's ankle joint limits. The device's efficacy was confirmed through tests on 10 subjects. |
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Robust Impedance-based Position Control For Safe Human-Robot Interaction |
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Wonbum Yun, Sehoon Oh(DGIST, Korea) |
| A novel Workspace Force/Acceleration Disturbance Observer (WFADOB) controller is proposed, which utilizes both interaction force and acceleration to design a disturbance observer loop, enabling precise motion tracking even with low-impedance gain settings. Additionally, the proposed controller offers fine impedance rendering performance, offering safe contact while maintaining low impedance. This paper discusses the problem of motion tracking performance due to friction and the issue of interaction force that arises during contact. The proposed controller is theoretically analyzed and experimentally verified, demonstrating its performance compared to conventional methods. |
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Disturbance Observer-based Torque Control of Coaxial Magnetic Gear and Tool Changing Application |
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Hangyeol Song, Edgar Lee, Seokhwan Jeong(Sogang University, Korea) |
| The non-contact power transmission features of the coaxial magnetic gear has gotten considerable interest due to its numerous advantages. It provides enhanced efficiency and reduced noise during power transmission, and its inherent backdrivability allows it to withstand overload impact. Furthermore, the magnets incorporated into the coaxial magnetic gear impart it with a spring-like property, enabling torque control without the need for a torque sensor, similar to the control mechanism employed in series elastic actuators. This study introduces a torque control algorithm for the coaxial magnetic gear and proposes a tool-changing mechanism that utilizes the magnetic coupling. |
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A Novel Winding Approach with Disturbance Observer |
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Kwanho Yu, Yejin Shin, Jungsu Choi(Yeungnam University, Korea) |
| The filament winding method faces obstacles in improving Type IV hydrogen tank quality. A new approach considers tow prepreg tension control and direct force application during winding. However, force sensor integration is complex due to winding machine intricacies and tow prepreg characteristics. To address this, we propose a sensorless force control method. This method involves pressing the tow prepreg directly to achieve the innovative winding process. Utilizing a disturbance observer for reaction force and end-effector position control enables effective force measurement without force sensors. Moreover, leveraging external tank data enhances force control performance. |
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Interaction Control for Isometric, Isotonic, and Isokinetic Exercise using Series Elastic Actuator |
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Seokho Yang, Jaegeun Jang, Chan Lee(Yeungnam University, Korea) |
| This paper introduces a novel control method utilizing impedance(admittance) control to generate exercise loads based on the muscle contraction model. Subsequently, the proposed method is applied to an actuator equipped with a torque sensor, and an analysis is conducted to examine the impact of the torque sensor's stiffness on control performance. Through experimental evaluation, a comparative analysis of control performance based on different stiffness values is conducted, confirming the capability of the torque sensor-equipped actuator to generate exercise loads based on the muscle contraction model. |
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