Robot assisted standing-up in persons with lower limb prostheses

Abstract

Abstract-Robot assisted standing-up manoeuver was tested in an intact person and a person after above-knee amputation. The subjects were asked to use as much leg activity as possible to lift their body while maintaining contact with the robot. The robot guided the subjects with three reference speeds. Kinematics and external forces acting on the body were recorded. The robot influence on the hip trajectory and the torques of the leg joints were studied. The subjects were able to track the robot movement. Thus, it is possible to use the robot to guide an impaired person along a desired trajectory during the standing-up process. In this way the impaired persons can be trained to accomplish an efficient sit-to-stand movement, while different trajectories of raising can be preprogrammed. Keywords -Standing-up, assistive robot, above-knee amputation I. INTRODUCTIONThe ability to stand up from a sitting position is essential for a person's independency. Successful raising is also the prerequisite for walking. However, the standing-up manoeuvre requires higher torque and larger ranges of motion in the joints of the lower limbs than walking. Standing-up is a frequent human activity. On average a healthy person stands up four times per hour [1]. Persons after the lower limb amputation are faced with the necessity to relearn standing-up in a different way than they were used to. Usually higher joint torques in the intact leg and improved balancing are required.A robot was built to assist disabled persons during the sit-to-stand transfer. The robot is meant to be used as a training device, an assessment tool and to study the rising manoeuvre. When training with the robot assistive device, a disabled person can safely approach limits of his/her capabilities without risking to fall. Using the robot to measure rising is more comfortable than placing sensors such as infrared markers or goniometers on the patient's body. The assistive device can be programmed to interact with a person's voluntary activity in order to gain information about the standing-up process. The suitability to support paraplegic patients rising by the help of functional electrical stimulation was evaluated in [2]. A similar passive device supporting part of a paraplegic patient's body weight was used to study the FES control strategies during standing-up [3]. We believe that other categories of disabled persons, such as amputees and aging population can benefit from robot assisted training of standing-up.The optimal trajectory of an amputee may differ from the optimal trajectory of an intact person. The present paper is a preliminary study mainly focused on the use of the robot as a device to guide a patient along a desired preprogrammed trajectory. Special attention was paid to interaction between the subject and the robot. II. METHODOLOGYThe assistive robot resembles to half of a seesaw construction and has one active and one passive degree of freedom (Fig. 1). A rotating segment is driven by a hydraulic cylinder. A commercially available bicycle seat s...

TRIZ and AHP in Early Design Stage of a Novel Reconfigurable Wheelchair

“…Year References Wheelchair with swiveling, reclining, and lifting chair capabilities 1991 [6] Wheelchair with hip-up capability 1992 [7] Robot-assisted sit to stand transfer for lower limb prostheses 2001 [8] Walking aid with feature to assist elders for Sit to Stand transfer 2002 [9] Wheelchair with lifting and hip-up functions 2004 [10] Chair to help in transformation from Sit to Stand for low seat 2010 [11] Prototype of a reconfigurable wheelchair for sit to stand transfer 2016 [12] Further, a wheelchair incorporated with standing feature enables users to have a better accessibility along with various health benefits such as 125 enhanced blood circulation, reduced risk of pressure sores, etc [5] Both backrest adjustment as well as standing feature of the wheelchair allows the user to exercise so that physical damage prevention and physical rehabilitation can be attained. Thus, reconfigurable wheelchair built-in with sit-to-stand and sit-to-sleep capabilities can be a practical solution for such wheelchair user population to promote their quality of life (QoL), safety and comfort.…”

Design and evaluation of a double rope rehabilitation robot for sit-to-stand training

“…10 In sit-to-stand training, lower limb prostheses were tested to guide the injured person to train along required trajectories. 11 Robot Lokomat used independent DC servomotors to drive hip and knee joints achieving positive and negative rotation, which imitates the behavior of humans. 12 However, this type of rehabilitation robots cannot reflect human motion intention intelligently, they may only drive the limb movement without considering the body strength feedback, which may lead to no obvious rehabilitation effect.…”

A Sit-to-Stand Training Robot and Its Performance Evaluation: Dynamic Analysis in Lower Limb Rehabilitation Activities

“…But these rehabilitation activities may not ensure that training is undertaken in a natural and comfortable trajectory for the patients; moreover inadequate trajectory training may lead the injured limb to develop an unnatural trajectory. Meanwhile, rehabilitation robots with prescribed movement pattern or interactive motion rehabilitation have been developed for naturalistic motion and body weight supported training (10)(11)(12)(13) , and a gravity-balancing leg passive orthosis also performed well in trajectory training (14) . But these rehabilitation systems are not capable of intelligently interpreting human intentions; they may just support an injured limb of a patient without concentrating on retraining weak points that may lead to unobvious rehabilitation effects.…”

“…4-9, and respect patients' moving intention which improved the weak point of Ref. [10][11][12][13][14]. In addition, a game control method was developed to improve the coordination of brain and limbs, which achieved the advantage of Ref.…”