Joint motion control of a powered lower limb orthosis for rehabilitation

Abstract

Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training reduces the incidence of these secondary pathologies, but the physical effort involved in this training is such that there is poor compliance. This paper reports on the design and control of a new "human friendly" orthosis (exoskeleton), powered by high power pneumatic Muscle Actuators (pMAs). The combination of a highly compliant actuation system, with an intelligent embedded control mechanism which senses hip, knee, and ankle positions, velocity, acceleration and force, produces powerful yet inherently safe operation for paraplegic patients. This paper analyzes the motion of ankle, knee, and hip joints under zero loading, and loads which simulate human limb mass, showing that the use of "soft" actuators can provide a smooth user friendly motion. The application of this technology will greatly improve the rehabilitative protocols for paraplegic patients.

Improving Interactions between a Power-Assist Robot System and Its Human User in Horizontal Transfer of Objects Using a Novel Adaptive Control Method

“…The system will be upgraded to a real multi-degree of freedom system and it will be evaluated properly for heavy objects. We will enhance the compliance of the actuation [37]. More human features will be investigated and be used to design the control to further improve the human-system interactions.…”

“…More human features will be investigated and be used to design the control to further improve the human-system interactions. The biomimetic and the psychophysical approaches to the control design will be considered for other assistive and interactive applications such as rehabilitation, healthcare, and so forth [22,35,[37][38][39].…”

Recent Trends in Lower-Limb Robotic Rehabilitation Orthosis: Control Scheme and Strategy for Pneumatic Muscle Actuated Gait Trainers

“…Conversely, by focusing on the development of "human friendly" exoskeleton orthosis systems, Costa et al in 2006 proposed a powered lower-limb orthosis, which can produce powerful, yet naturally safe, operations for paraplegic patients, as illustrated in Figure 5a [37]. This was realized by combining a highly compliant actuator (PMA) with an embedded intelligent control system (a three level PID joint torque control scheme) to manipulate the antagonistic actuators of the exoskeleton.…”

Soft Pneumatic Actuators for Rehabilitation

“…Artificial muscles can thus be integrated in rehabilitation equipment based on typical robotics concepts, and can be used to control aids for the disabled (e.g., hands and upper and lower limbs) [23][24][25][26][27][28]. For wearable devices, the major considerations to be borne in mind to ensure that they cannot only be comfortable worn, but are also dependable and durable, are weight, power and deformability.…”