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Weight gain and stretched and weakens abdominal muscles by an enlarging gravid uterus are remarkable features during pregnancy. These changes elicit postural and movement instability and place strain on various body segments. In general, agonist and antagonist muscles of body segments act simultaneously to increase joint stabilization during human movements. The co-contraction might be well observed...
Nowadays, decreasing birthrate and aging population become to be the serious social problem in Japan. Therefore, needs of assistive devices are more and more increasing. When people use such assistive devices, there is a risk that devices cost user excessive burden. So analysis and evaluation of motions and load of person who uses assistive devices are necessary. In this paper, a model to analyze...
This paper describes the reduction of chattering in functional electrical stimulation (FES) with Smith compensator. We proposed a bilateral controller using FES. In the bilateral controller, in addition to normal remote control, the reaction forces of the distant location are transmitted back to the operator. Therefore, the operator feels like being in the distant location. In controlling of the human...
The elderly sometimes fall owing to tripping caused by decreased dorsal flexion during the swing phase. A wearable assist device that was able to increase dorsal flexion to reduce the risk of tripping was proposed in this study. This device assists in dorsal flexion during the swing phase by transferring the tension force from the upper body to the foot by connecting them using strings. To improve...
Lower back pain is a major health concern worldwide. One cause of lower back pain is the burden on the lumbar region caused by the handling of heavy objects. To reduce this burden, the Ministry of Health, Labour and Welfare in Japan has recommended “squat lifting.” However, this technique, which supports a large force on lower limbs, is not very popular. Therefore, we aimed to develop a power assist...
This paper investigates a functional electrical stimulation (FES) cycling system on velocity tracking control for human limbs in order to stimulate multiple muscle groups continuously and simultaneously at all angles during pedaling. A stationary cycle and rider is modeled as an Euler Lagrange system by using a closed-chain mechanism. Stability of the developed controller is analyzed through Lyapunov-based...
Since manual rehabilitation therapy can be taxing for both the patient and the physiotherapist, a gait rehabilitation robot has been built to reduce the physical strain and increase the efficacy of the rehabilitation therapy. The prototype of the gait rehabilitation robot is designed to provide assistance while walking for patients with abnormal gait pattern and it can also be used for rehabilitation...
This work presents a wearable device and the algorithms for quantitative modelling of joint spasticity and its application in a pilot group of subjects with different levels of spinal cord injury. The device comprises light-weight instrumented handles to measure the interaction force between the subject and the physical therapist performing the tests, EMG sensors and inertial measurement units to...
Some unilateral lower-limb amputees load the intact limb more than the prosthetic limb. This can cause chronic pains, fatigue, lumbago, and joint diseases, including knee osteoarthritis. To avoid and counteract these symptoms it is necessary to improve their asymmetric gait. Increasing the function of the hip abductor muscle is important to maintaining symmetrical weight distribution. Therefore, the...
Two common rehabilitation therapies for individuals possessing neurological conditions are functional electrical stimulation (FES) and robotic assistance. This paper focuses on combining the two rehabilitation strategies for use on the biceps brachii muscle group. FES is used to elicit muscle contractions to actuate the forearm and a rehabilitation robot is used to challenge the muscle group in its...
Sit-to-stand transition is an essential step in a lower limb rehabilitation therapy, mainly for assisting the patient to transit from wheel chair to the next level of therapy. A mixed stiffness-damping control adaptation is proposed for this task which will help in reaching the final position with a constant velocity. A combination of control model is proposed to ensure the initiation and the final...
In this study, we developed a 4-degrees of freedom (DOF) force feedback device independent of its operational component comprising pneumatic artificial muscles and magnetorheological clutches. Research and development of force feedback devices is becoming popular in fields such as entertainment, remote operation, and rehabilitation. These areas of research are related to virtual reality and augmented...
We present a novel control approach for assistive lower-extremity exoskeletons. In particular, we implement a virtual pivot point (VPP) template model inspired leg force feedback based controller on a lower-extremity powered exoskeleton (LOPES II) and demonstrate that it can effectively assist humans during walking. It has been shown that the VPP template model is capable of stabilizing the trunk...
Lower back pain is a major health concern worldwide. One cause of lower back pain is the burden on the lumbar region caused by the handling of heavy objects. To reduce this burden, the Ministry of Health, Labour and Welfare in Japan has recommended “squat lifting.” However, this technique, which supports a large force on lower limbs, is not very popular. Therefore, we aimed to develop a power assist...
Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable...
Lower Limb Exoskeleton robot that can facilitate stair walking is a big challenge, most systems could only provide level ground walking. In this study, a lightweight (0.5kg at ankle, 0.5kg at waist for control box) and autonomous exoskeleton Ankle Robot was proposed to provide power assistance for gait training of chronic stroke patients and it can facilitate three walking conditions in real-time:...
Functional electrical stimulation (FES) is a promising solution for restoring functional motion to individuals with paralysis, but the potential for achieving full-arm reaching motions with FES for various desired tasks has not been realized. We present an open-loop controller capable of calculating and applying the necessary muscle stimulations to hold the wrist of an individual with high tetraplegia...
In this paper we present the design of a one degree of freedom assistive platform to augment the strength of upper limbs. The core element is a variable stiffness actuator, closely reproducing the behavior of a pair of antagonistic muscles. The novelty introduced by this device is the analogy of its control parameters with those of the human muscle system, the threshold lengths. The analogy can be...
Crouch or “flexed knee” gait is a pathological gait pattern affecting many individuals with cerebral palsy. One proposed method to alleviate crouch is to provide robotic assistance to knee extension during walking. The purpose of this study was to evaluate how the magnitude of knee extensor torque affects knee kinematics, kinetics, and muscle activity. Motion capture, ground reaction force and electromyography...
A positive training synergy can be obtained when two individuals attempt to learn the same motor task while mechanically coupled to one another. In this paper, we have studied how mimicking this interaction through impedance control can be exploited to improve assistance delivered by hand exoskeleton devices during rehabilitation. In this context, the machine and user take complementary roles akin...
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