Limits...
Design of a novel telerehabilitation system with a force-sensing mechanism.

Zhang S, Guo S, Gao B, Hirata H, Ishihara H - Sensors (Basel) (2015)

Bottom Line: Patients' safety is guaranteed by monitoring the motor's current from the exoskeleton device.To compensate for any possible time delay or data loss, a torque-limiter mechanism was also designed in the exoskeleton device for patients' safety.Finally, we successfully performed a system performance test for passive training with transmission control protocol/internet protocol communication.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan. s13d505@stmail.eng.kagawa-u.ac.jp.

ABSTRACT
Many stroke patients are expected to rehabilitate at home, which limits their access to proper rehabilitation equipment, treatment, or assessment by therapists. We have developed a novel telerehabilitation system that incorporates a human-upper-limb-like device and an exoskeleton device. The system is designed to provide the feeling of real therapist-patient contact via telerehabilitation. We applied the principle of a series elastic actuator to both the master and slave devices. On the master side, the therapist can operate the device in a rehabilitation center. When performing passive training, the master device can detect the therapist's motion while controlling the deflection of elastic elements to near-zero, and the patient can receive the motion via the exoskeleton device. When performing active training, the design of the force-sensing mechanism in the master device can detect the assisting force added by the therapist. The force-sensing mechanism also allows force detection with an angle sensor. Patients' safety is guaranteed by monitoring the motor's current from the exoskeleton device. To compensate for any possible time delay or data loss, a torque-limiter mechanism was also designed in the exoskeleton device for patients' safety. Finally, we successfully performed a system performance test for passive training with transmission control protocol/internet protocol communication.

Show MeSH

Related in: MedlinePlus

Output torque of the master device.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4481901&req=5

sensors-15-11511-f014: Output torque of the master device.

Mentions: We implemented a teleoperation to test the slave device can track the motion of therapists while the output impedance of master device is adjusted to near-zero. The master and slave devices were located in different rooms in Kagawa University, where the network latency is not significant. The two sides communicated with transmission control protocol/internet protocol. The experimental setup of the master side is shown in Figure 11. A subject instead of a therapist performed the training as a surrogate therapist. The subject was knowledgeable in rehabilitation training. The user interface included the operation panel, a real-time video, and a virtual model. The operation panel was used for switching the training tasks, saving training data, etc. The real-time video was transmitted from the slave side via a web camera. The master system consisted of the motor driver, controller, master device, and an inertia sensor (MTx sensor). The setup of the slave side is shown in Figure 12. We used a healthy subject (age 27 years, male) as a surrogate patient. The design of this telerehabilitation system focuses on elbow joint motor recovery. Therefore, on the slave side, only the motor in the elbow joint was driven and controlled (i.e., the motor installed in the wrist part of the exoskeleton device was not used). After the patient connected his system with the therapist’ side, the therapist started the training while monitoring the status of the patient. In this test, the passive training modality was selected and the output impedance of master device was set to near-zero. In this modality, the patient maintained a relaxed position while the therapist provided the desired motion pattern. The motion from the therapist was measured with the inertia sensor with a 1000-Hz sampling frequency. The exoskeleton device tracked the motion well with a closed-loop position control method. The experimental results are shown in Figure 13 and Figure 14, showing that the exoskeleton device was able to track the motion from therapists well and the output torque from the master device was controlled within a small value. The average time delay during this experiment was 0.6788 ms. The surrogate patient did not feel obvious time delay. As a healthy subject was used as a surrogate patient, the subject was relaxed and followed the motion of the therapists. Therefore, a spasm condition was not tested. The stability of the telrehabilitation system for spastic conditions will be tested in our future studies.


Design of a novel telerehabilitation system with a force-sensing mechanism.

Zhang S, Guo S, Gao B, Hirata H, Ishihara H - Sensors (Basel) (2015)

Output torque of the master device.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481901&req=5

sensors-15-11511-f014: Output torque of the master device.
Mentions: We implemented a teleoperation to test the slave device can track the motion of therapists while the output impedance of master device is adjusted to near-zero. The master and slave devices were located in different rooms in Kagawa University, where the network latency is not significant. The two sides communicated with transmission control protocol/internet protocol. The experimental setup of the master side is shown in Figure 11. A subject instead of a therapist performed the training as a surrogate therapist. The subject was knowledgeable in rehabilitation training. The user interface included the operation panel, a real-time video, and a virtual model. The operation panel was used for switching the training tasks, saving training data, etc. The real-time video was transmitted from the slave side via a web camera. The master system consisted of the motor driver, controller, master device, and an inertia sensor (MTx sensor). The setup of the slave side is shown in Figure 12. We used a healthy subject (age 27 years, male) as a surrogate patient. The design of this telerehabilitation system focuses on elbow joint motor recovery. Therefore, on the slave side, only the motor in the elbow joint was driven and controlled (i.e., the motor installed in the wrist part of the exoskeleton device was not used). After the patient connected his system with the therapist’ side, the therapist started the training while monitoring the status of the patient. In this test, the passive training modality was selected and the output impedance of master device was set to near-zero. In this modality, the patient maintained a relaxed position while the therapist provided the desired motion pattern. The motion from the therapist was measured with the inertia sensor with a 1000-Hz sampling frequency. The exoskeleton device tracked the motion well with a closed-loop position control method. The experimental results are shown in Figure 13 and Figure 14, showing that the exoskeleton device was able to track the motion from therapists well and the output torque from the master device was controlled within a small value. The average time delay during this experiment was 0.6788 ms. The surrogate patient did not feel obvious time delay. As a healthy subject was used as a surrogate patient, the subject was relaxed and followed the motion of the therapists. Therefore, a spasm condition was not tested. The stability of the telrehabilitation system for spastic conditions will be tested in our future studies.

Bottom Line: Patients' safety is guaranteed by monitoring the motor's current from the exoskeleton device.To compensate for any possible time delay or data loss, a torque-limiter mechanism was also designed in the exoskeleton device for patients' safety.Finally, we successfully performed a system performance test for passive training with transmission control protocol/internet protocol communication.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan. s13d505@stmail.eng.kagawa-u.ac.jp.

ABSTRACT
Many stroke patients are expected to rehabilitate at home, which limits their access to proper rehabilitation equipment, treatment, or assessment by therapists. We have developed a novel telerehabilitation system that incorporates a human-upper-limb-like device and an exoskeleton device. The system is designed to provide the feeling of real therapist-patient contact via telerehabilitation. We applied the principle of a series elastic actuator to both the master and slave devices. On the master side, the therapist can operate the device in a rehabilitation center. When performing passive training, the master device can detect the therapist's motion while controlling the deflection of elastic elements to near-zero, and the patient can receive the motion via the exoskeleton device. When performing active training, the design of the force-sensing mechanism in the master device can detect the assisting force added by the therapist. The force-sensing mechanism also allows force detection with an angle sensor. Patients' safety is guaranteed by monitoring the motor's current from the exoskeleton device. To compensate for any possible time delay or data loss, a torque-limiter mechanism was also designed in the exoskeleton device for patients' safety. Finally, we successfully performed a system performance test for passive training with transmission control protocol/internet protocol communication.

Show MeSH
Related in: MedlinePlus