Developments of a Knee Motion Assist Mechanism for Wearable Robot with a Non-circular Gear and Grooved Cams

Terada, Hidetsugu; Zhu, Yuxuan; Suzuki, M.; Cheng, Chung–Ying; Takahashi, Ryutaro

doi:10.1007/978-94-007-2727-4_6

Cited by 39 publications

(18 citation statements)

References 2 publications

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“…And, during the 15 to 90 degrees, knee joint rotates with gliding to the back direction, at the bones contacts section, as shown in Fig.4 (23) . Also, that motion at the bone center section is well known.…”

Section: Assisting Mechanism For Knee Jointmentioning

confidence: 98%

Study of Wearable Knee Assistive Instruments for Walk Rehabilitation

Zhu

Nakamura

Ito

et al. 2012

JAMDSM

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A wearable Knee Assistive Instrument for the walk rehabilitation was newly developed. Especially, this system aimed at supporting the rehabilitation for the post-TKA (Total Knee Arthroplasty) which is a popular surgery for aging people. This system consisted of an assisting mechanism for the knee joint, a hip joint support system and a foot pressure sensor system. The driving system of this robot consisted of a CPU board which generated the walking pattern, a Li-ion battery, DC motors with motor drivers, contact sensors to detect the state of foot and potentiometers to detect the hip joint angle. The control method was proposed to reproduce complex motion of knee joint as much as possible, and to increase hip or knee flexion angle. Especially, this method used the timing that heel left from the floor. This method included that the lower limb was raised to prevent a subject's fall. Also, the prototype of knee assisting system was tested. It was confirmed that the assisting system is useful.

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Section: Assisting Mechanism For Knee Jointmentioning

confidence: 98%

Study of Wearable Knee Assistive Instruments for Walk Rehabilitation

Zhu

Nakamura

Ito

et al. 2012

JAMDSM

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“…In this mechanism, the rotational force was accumulated in the spiral spring during knee flexion, and that released when the joint is fully extended. In addition, based on the previously reported knee motion of Japanese people (Terada et al, 2012), the cam profiles and the center locus of the non-circular gear are generated according to the "asymmetrical-modified-trapezoid acceleration curve". The theoretical relationship between the rotation angles of the knee joint, the roll-back motion displacement, and the assistive torque of the flat spiral spring are shown in Fig.…”

Section: Design Of the Assistive Mechanism For The Knee Jointmentioning

confidence: 99%

“…12. The instrument is attached to a healthy person (25age, men) and the cam profiles are optimized for the subject (Terada, 2012). Because the influence of fatigue is significant, the test are repeated only once per subject.…”

Section: Verification Of the Prototype Instrumentmentioning

confidence: 99%

Development of an assistive instrument for lifting motion using driving springs

Terada

Makino

Ishida

et al. 2017

JAMDSM

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To assist in lifting heavy weight objects from the floor, an assistive instrument that can be worn on the hip and knee joints has been developed. The instrument was driven by coil and flat spiral springs to operate for a long time. At this instrument, the assistive mechanism for the hip joint comprised a plate cam with a "sine-output" oscillating follower and a compression coil spring. The assistive mechanism for the knee joint comprised a non-circular gear, two grooved cams and a flat spiral spring. To eliminate the influence of abduction or adduction and a medial or lateral rotation, two types of freely rotating joints were attached to each of these mechanisms. Based on the analysis of the lifting motion of an object from the floor, it was concluded that the torque applied on the hip and knee joints depends on the individual differences in body height and a body weight, and can be estimated using a two dimensional model. A prototype of the proposed instrument was fabricated and tested. This instrument can be used to reduce the required muscle activities of the hip and knee joints by about 15% compared to while lifting without the instrument when subjected to a force of 98N by an object. Furthermore, the results showed that the assistive instrument exhibits sufficient performance in aiding the lifting motions.Keywords : Assistive instrument, Lifting, Hip joint, Knee joint, Flexion, Extension, Driving spring IntroductionA variety of power assistive devices, that generally use electrical or hydraulic actuators, have been developed in Japan (Ishii et al., 2004 andSato et al., 2010). However, these devices are heavy and not suitable to be used for a long duration. Previously, we developed a spring-driven instrument to assist the standing-up motion for elderly people (Terada et al., 2016). This device was designed to be light weight and to operate for a long duration. The behavior of the standing-up motion is similar to the motion of lifting an object from the floor. However, this instrument could not provide enough assistive power to enable a lifting motion. In this study, the lifting motion of a heavy weight object from the floor was analyzed to estimate the generated torques of hip and knee joints. Then, an assistive instrument was designed which can be used in any environmental conditions even without electric supply. Furthermore, to confirm the usefulness of the proposed design, a prototype is tested experimentally to characterize the reduction in the required muscle activity at the hip and knee joints as a result of using the instrument. Recently, in Japan, the number of elderly people has rapidly increased and the aging society causes various problems (Yoshimura, 2009). Moreover, at care centers and nursing homes, the number of nursing aid and nursing care personnel is insufficient. Furthermore, there are numerous cases that require flexible judgment by nursing personnel such as assisting while transferring a person from a wheelchair or while bathing, which are difficult to automate using robots. On t...

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“…Therefore, a conventional mechanism which has 1-DOF rotation joint is insufficient. Considering this point, a knee joint driving mechanism which is attached on the outside of leg has been newly developed [4].…”

Section: Knee Joint Assist Mechanismmentioning

confidence: 99%

Development of a Wearable Assist Robot for Walk Rehabilitation After Knee Arthroplasty Surgery

Terada

Zhu

HORIGUCHI

et al. 2012

Advances in Mechanisms Design

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In Japan, it is popular that the disease knee joints will be replaced to artificial joints by surgery. And we have to assist so many patients for walk rehabilitation. So, the wearable assist robot has been developed. This robot includes the knee motion assist mechanism and the hip joint support mechanism. Especially, the knee motion assist mechanism consists of a non-circular gear and grooved cams. This mechanism rotates and slides simultaneously, which has two degree-of-freedom. Also, the hip joint support mechanism consists of a hip brace and a ball-joint. This mechanism can avoid motion constraints which are the internal or external rotation and the adduction or abduction. Then, the control algorithm, which considers an assisting timing for the walk rehabilitation, has been proposed. A sensing system of a walk state for this control system uses a heel contacts sensor and knee and hip joint rotation angle sensors. Also, the prototype robot has been tested. And it is confirmed that the assisting system is useful.

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Developments of a Knee Motion Assist Mechanism for Wearable Robot with a Non-circular Gear and Grooved Cams

Cited by 39 publications

References 2 publications

Study of Wearable Knee Assistive Instruments for Walk Rehabilitation

Study of Wearable Knee Assistive Instruments for Walk Rehabilitation

Development of an assistive instrument for lifting motion using driving springs

Development of a Wearable Assist Robot for Walk Rehabilitation After Knee Arthroplasty Surgery

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