Human power augmentation devices are robotic systems used for assisting the operator in the execution of manipulative/walking tasks and with the capability of amplifying human force. In this paper, we present new approach for the synthesis of an LQG controller that, with respect to other solutions, does not require direct measurements of interaction forces between the robotic device and the external environment. The experimental performance of the devised controller is shown on a testbed with 1 DOF.

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In this study, we attempt to quantify the relation-ship etween significant arm-clutch loading, leg restriction, and motor paralysis, and analyze lumbar joint trajectories in the orthotic gait of paraplegic subjects and in the ordinary and orthotic gaits of a nor-mal subject, by using an inverted pendulum model. With leg restriction, the trajectories are located in front of an equilibrium point of the inverted pendulum, and the loading is higher due to the influence of the gravity moment. Comparing the trajectories of paraplegic and normal gait with orthosis in the hori-zontal plane,the trajectory in the paraplegic subjects was rectilinear, while that in the normal subject was curved in the direction toward the equilibrium point. The loading is lower in the curved trajectory than in the straight trajectory because of the trade-off between gravity and inertia. These results sug-gest that the increase in the distance between the trunk movement and the equilibrium point of the in-verted pendulum results in significant loading due to leg restriction and motor paralysis in the orthotic gait of paraplegics.

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A number of orthoses have been developed to restore stance and walking in paraplegic subjects. Compliance, however, has been limited, mainly owing to walking effort. Use of the forces produced by actuators is an effective way to solve the problem of the considerable effort required for orthotic gait, namely high muscular effort and high energy expenditure. The purpose of the present study was to investigate the effects of assistance by external actuators on the orthotic gait of spinal cord injury (SCI) patients. Two kinds of linear actuator were developed by using direct current (d.c.) motors for assisting the knee and hip joint of a gait orthosis. They were mounted on the knee and hip joint of a commercial advanced reciprocating gait orthosis (ARGO), and a new two-degree-of-freedom externally powered gait orthosis was thus developed. The orthosis was assessed through inter-subject expe-riments on five male adult complete SCI patients. Owing to the short training period available for the assisted gait, simultaneous operation of both joint actuators was not conducted: either the knee actuation or the hip actuation was executed only. Thus, the knee actuator and the hip actuator were assessed with a T12 subject and with subjects for T5, T8, T11, and T12 respectively. The motions of the gaits, assisted by the linear actuators, were measured by a Vicon 370 system, and the general gait parameters and compensato-ry motions were evaluated. Results demonstrated that all subjects could walk without falling, assisted either by the knee or the hip actuator; both the knee and hip joint actuator increased the gait speed and the step length; the knee flexion produced by the orthosis improved the dynamic cosmesis of walking; and lateral compensatory motions as well as vertical ones tended to decrease when the hip joint was assisted, which could contribute to a reduction in walking effort.

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The basic concepts for exoskeletal systems have been suggested for some time with applications ranging from construction, manufacturing and mining to rescue and emergency services. In recent years, research has been driven by possible uses in medical/rehabilitation and milita-ry applications. Yet there are still significant barriers to the effective use and exploitation of this technology. Among the most pertinent of these factors is the power and actuation system and its impact of control, strength, speed and, perhaps most critically, safety. This work describes the design, construc-tion and testing of an ultra low-mass, full-body exoskeleton system having seven degrees of freedom (DOFs) for the upper limbs and five degrees of freedom (DOFs) for each of the lower limbs. This low mass is prima-rily due to the use of a new range of pneumatic muscle actuators as the power source for the system. The work presented will show how the system takes advantage of the inherent controllable compliance to produce a unit that is powerful, providing a wide range of functionality (motion and forces over an extended range) in a manner that has high safety integrity for the user. The general layout of both the upper and the lower body exoskeleton is presented together with results from preliminary experiments to demonstrate the potential of the device in limb retraining, rehabilitation and power assist (augmentation) operations.

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An exoskeleton is a wearable robot with joints and links corresponding to those of the human body.With applications in rehabilitation medicine, virtual reality simulation, and teleoperation, exoskeletons offer benefits for both disabled and healthy populations. Analytical and expe-rimental approaches were used to develop, integrate, and study a powered exoskeleton for the upper limb and its application as an assistive device. The kinematic and dynamic dataset of the upper limb during daily living activities was one among several factors guiding the development of an anthropomorphic, seven degree-of-freedom, powered arm exoskeleton. Additional design inputs include anatomical and physiological considerations, workspace analyses, and upper limb joint ranges of motion. Proximal placement of motors and distal placement of cable-pulley reductions were incorporated into the design, leading to low inertia, high-stiffness links, and back-drivable transmissions with zero backlash. The design enables full gleno-humeral, elbow, and wrist joint functionality. Establishing the human-machine interface at the neural level was facilitated by the development of a Hill-based muscle model (myoprocessor) that enables intuitive interaction between the operator and the wearable robot. Potential applications of the exoskele-ton as a wearable robot include an assistive (orthotic) device for human power amplifications, a therapeutic and diagnostics device for physiotherapy, a haptic device in virtual reality simulation, and a master device for teleoperation.

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