Lower body exoskeleton-supported compliant bipedal walking for paraplegics: How to reduce upper body effort?

IEEE Trans. Human-Mach. Syst.

Nishimura

Hyodo

et al. 2015

Self Cite

104

Abstract-This paper presents a wearable upper body exoskeleton system with a model based compensation control framework to support robot-aided shoulder-elbow rehabilitation and power assistance tasks. To eliminate the need for EMG and force sensors, we exploit off-the-shelf compensation techniques developed for robot manipulators. Thus target rehabilitation tasks are addressed by using only encoder readings.A proof of concept evaluation was conducted with 5 able-bodied participants. The patient-active rehabilitation task was realized via observer-based user torque estimation, in which resistive forces were adjusted using virtual impedance. In the patient-passive rehabilitation task, the proposed controller enabled precise joint tracking with a maximum positioning error of 0.25 degrees. In the power assistance task, the users' muscular activities were reduced up to 85% while exercising with a 5 [kg] dumbbell. Therefore, the exoskeleton system was regarded as being useful for the target tasks; indicating that it has a potential to promote robot-aided therapy protocols.

“…Currently, the lower extremity of TTI-Exo is being employed for the paraplegia walking support task [28]. Therefore, whole-body motion control will be our next assignment.…”

Section: Discussionmentioning

confidence: 99%

Proof of Concept for Robot-Aided Upper Limb Rehabilitation Using Disturbance Observers

IEEE Trans. Human-Mach. Syst.

Nishimura

Hyodo

et al. 2015

Self Cite

104

“…Starting with Vukobratovic's work [1], numerous lower body exoskeletons have been developed for various applications, ranging from power augmentation [2] and robot-aided rehabilitation [3] to paraplegia walking support [4]- [6] and gait assistance [7]- [10]. An exhaustive review on lower limb rehabilitation devices is provided in [11].…”

Section: Introductionmentioning

confidence: 99%

“…Though the software-controlled active compliance schemes can enhance environmental interaction capabilities [6]- [8], the rest of the listed benefits may not be acquired due to fundamental open-loop characteristics of actuators with low compliance [13]. Consequently, several exoskeletons are powered via passively compliant actuators [10], [14]- [16].…”

Section: Introductionmentioning

confidence: 99%

Towards balance recovery control for lower body exoskeleton robots with Variable Stiffness Actuators: Spring-loaded flywheel model

Doppmann

2015 IEEE International Conference on Robotics and Automation (ICRA)

Hamaya

et al. 2015

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This paper presents a biologically-inspired realtime balance recovery control strategy that is applied to a lower body exoskeleton with variable physical stiffness actuators at its ankle joints. For this purpose, a torsional spring-loaded flywheel model is presented to encapsulate both approximated angular momentum and variable physical stiffness, which are crucial parameters in describing the postural balance. In particular, the incorporation of physical compliance enables us to provide three main contributions: i) A mathematical formulation is developed to express the relation between the dynamic balance criterion ZMP and the physical ankle joint stiffness. Therefore, balancing control can be interpreted in terms of ankle joint stiffness regulation. ii) 'Variable physical' stiffness is utilized in the bipedal robot balance control task for the first time in the literature, to the authors' knowledge. iii) The variable physical stiffness strategy is compared with the optimal constant stiffness strategy by conducting experiments on our exoskeleton robot. The results indicate that the proposed method provides a favorable balancing control performance to cope with unperceived perturbations, in terms of center of mass position regulation, ZMP error and mechanical power.

“…Due to the loss of the sensorimotor control concerning the lower body of the paraplegics, the common control strategy of the exoskeleton robots is to track preplanned joint trajectories with high-gain controllers, e.g., PID. Although such strategies are sufficient for basic walking support, they cannot guarantee a feasible walking performance of the human-robot integrated system [13]. Since the mutual interaction of the human-robot integrated system with the outer environment is not included within the controller, a consistent and global characterization of the walking motion cannot be acquired [14].…”

mentioning

confidence: 99%

A Soft+Rigid Hybrid Exoskeleton Concept in Scissors-Pendulum Mode: A Suit for Human State Sensing and an Exoskeleton for Assistance

2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR)

Acer

Barkana

et al. 2019

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In this paper, we present a novel concept that can enable the human aware control of exoskeletons through the integration of a soft suit and a robotic exoskeleton. Unlike the state-of-the-art exoskeleton controllers which mostly rely on lumped human-robot models, the proposed concept makes use of the independent state measurements concerning the human user and the robot. The ability to observe the human state independently is the key factor in this approach. In order to realize such a system from the hardware point of view, we propose a system integration frame that combines a soft suit for human state measurement and a rigid exoskeleton for human assistance. We identify the technological requirements that are necessary for the realization of such a system with a particular emphasis on soft suit integration. We also propose a template model, named scissor pendulum, that may encapsulate the dominant dynamics of the human-robot combined model to synthesize a controller for human state regulation. A series of simulation experiments were conducted to check the controller performance. As a result, satisfactory human state regulation was attained, adequately confirming that the proposed system could potentially improve exoskeleton-aided applications.