Performance Analysis of Torque-sensorless Assist Control of a Powered Exoskeleton Using Highly Back-drivable Actuators

Kanai, Yoshiki; Fujimoto, Yasutaka

doi:10.1109/indin41052.2019.8972220

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…In previous research, we did not consider the back drive efficiency when modeling an actuator module [21], [22]. In this section, we assume a single joint knee exoskeleton, the modeling of an actuator module and the torque estimation method considering back driving efficiency will be discussed.…”

Section: Modeling Of An Actuator Module and Torque Estimation Methods...mentioning

confidence: 99%

“…To improve the low backdrivability in high reduction ratio, Fujimoto et al conducted research to maximize the forward driving efficiency of a compound planetary reduction gearbox called bilateral drive gear [19], [20], [22], [22]. The researchers developed a gearbox prototype by obtaining the optimum parameters to formulate and maximize the forward drive efficiency of the type-3K [19] and type-2K-H [20].…”

Section: Introductionmentioning

confidence: 99%

“…The forward driving efficiency, backward driving efficiency, and reverse-drive start torque of the type-3K gearbox prototype were measured as 85.32%, 84.33%, and 0.0145 N•m, respectively. Kanai et al, reported results of external torque estimation using bilateral drive gear and realized high back drivability without additional elements [21], [22]. However, the authors designed only the actuator module and did not design a exoskeleton robot.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Torque-Sensorless Control for a Knee Exoskeleton Using Back-Drivable Actuators

Mori

Fujimoto

2022

2022 IEEE 17th International Conference on Advanced Motion Control (AMC)

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Exoskeleton robots have attracted significant attention in an increasingly aging global population with a declining birthrate. However, exoskeleton robots are not as popular as other service robots, such as communication robots and mobility robots. This is primarily because exoskeleton robots are in close contact with the human body, making safety and operability an issue. Reduction gears that show a high reduction ratio and high backdrivability have been proposed to solve these problems. Reduction gears with a high backdrivability can be used to estimate external force without using any additional devices, such as torque sensors. Therefore, this study introduces the development of an knee exoskeleton using a highly back-drivable gear. The size of a developed knee exoskeleton is approximately 220 W×60 D×65 H mm with a weight of approximately 1.2 kg. Moreover, we introduce an external force estimation method without a torque sensor. We used a multi encoder based disturbance observer (MEDOB) to estimate the external force. The experimental results of the external force estimation are presented. The root mean square error of the external force estimation without and with input assist torque were 0.162 and 0.128 N•m, respectively. We confirm that estimating external torque with high accuracy is possible with and without assisted control.

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Section: Modeling Of An Actuator Module and Torque Estimation Methods...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of Torque-Sensorless Control for a Knee Exoskeleton Using Back-Drivable Actuators

Mori

Fujimoto

2022

2022 IEEE 17th International Conference on Advanced Motion Control (AMC)

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“…Because the friction on the rotor can be efficiently compensated by a backdriving control system, this section mainly discusses the mover side friction. A friction model is built based on the following equation [9]:…”

Section: A Friction Modeling and Measurementmentioning

confidence: 99%

Sensor-less Back-driving Control of Direct-drivable RotLin Linear Series Elastic Actuator

Fujimoto

2021

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society

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In this paper, a novel direct-drivable RotLin (Rotary to Linear) linear serious elastic actuator is studied. The RotLin actuator converts rotary motion into linear motion through helical shaped permanent magnets on this rotor and translator. Because of removing mechanical transmissions of traditional electrical actuators, force density of the RotLin machine is high. In previous research, a load force sensor based back-driving system was implemented on the RotLin machine. In this research, a force-sensor-less back-drive control system is achieved. Firstly, magnetic force of the RotLin machine is analyzed based on linearized spring force model; then, mover side friction is measured and modeled; finally, a load force estimator is designed based on the spring force model and the friction model. Besides, the cogging torque is measured and compensated. In the end, a force-sensor-less force control system is designed based on rotor position control, and by setting the reference force to zero, a backdriving control was implemented on the prototype of the RotLin actuator. The experiment results verified accuracy of the designed load force estimator and back-drivability of the proposed system.

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Improved Trigger Time of Force Sensorless Power-Assisted System based on Fuzzy Logical Strategy and EMG Signal

Hsueh

Kao

et al. 2022

2022 25th International Conference on Mechatronics Technology (ICMT)

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Performance Analysis of Torque-sensorless Assist Control of a Powered Exoskeleton Using Highly Back-drivable Actuators

Cited by 6 publications

References 13 publications

Evaluation of Torque-Sensorless Control for a Knee Exoskeleton Using Back-Drivable Actuators

Evaluation of Torque-Sensorless Control for a Knee Exoskeleton Using Back-Drivable Actuators

Sensor-less Back-driving Control of Direct-drivable RotLin Linear Series Elastic Actuator

Improved Trigger Time of Force Sensorless Power-Assisted System based on Fuzzy Logical Strategy and EMG Signal

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