SensoryFusion 2013 Abstracts


Full Papers
Paper Nr: 1
Title:

Assessment of Walker-assisted Human Interaction from LRF and Wearable Wireless Inertial Sensors

Authors:

Maria Martins, Carlos Cifuentes, Arlindo Elias, Valmir Schneider, Anselmo Frizera and Cristina Santos

Abstract: This paper describes the assessment of basic walker-assisted human interaction based on a laser range finder (LRF) sensor and two inertial wearable sensors. Thirteen osteoarthritis patients and thirteen healthy subjects were selected to be part of this pilot experiment, which intends to acquire and calculate spatiotemporal and human-interaction parameters from walker-assisted ambulation. A comparison is made between the spatiotemporal parameters of healthy subjects and the ones of patients with osteoarthritis. Moreover, it is made an analysis of the effect that change of direction in walker-assisted ambulation can have on spatiotemporal parameters. Results have shown that 1) velocity, step length and distance to the walker are significantly affected by the change of direction, and 2) distance to the walker and step length can distinguish between healthy subjects and patients with osteoarthritis. In terms of human-interaction parameters, results show that a LRF sensor can correctly describe the trajectory and velocity of the user in relation to the walker. However, just the wearable sensors can characterize changes in direction. These results will be further used in the development of a robotic control that intends to detect the user's intention through LRF and inertial sensors, and respond accordingly.

Paper Nr: 2
Title:

Human-like Sensor Fusion Mechanisms in a Postural Control Robot

Authors:

Georg Hettich, Vittorio Lippi and Thomas Mergner

Abstract: In humans, maintaining body posture is a basis for many activities such as standing, walking or reaching. Human posture control involves multi-sensory integration mainly of joint angle, joint torque, vestibular and visual inputs. This integration provides humans with high flexibility and with robustness in terms of fail-safety. Roboticists may draw inspirations from the human control methods when building devices that interact with humans, such as prostheses or exoskeletons. This study presents a multisensory control method derived from human experiments, which is re-embodied in a biped postural control robot. The robot uses ankle and hip joints for balancing in the sagittal plane during external disturbances such as support surface motion. For the balancing, the robot estimates the external disturbances that have impact on its body by fusing the sensory signals. It then uses these estimates in negative feedback to command the local joint controls to compensate for the disturbances. This study describes the human sensor fusion mechanisms and their implementation into the robot, and it compares robot and human responses to support surface tilt. Measured balancing responses of the robot resemble in the main characteristics those of the human subjects, suggesting that the described sensor fusion mechanisms capture important aspects of human balancing.

Paper Nr: 3
Title:

Assessment of the Suitability of the Motorized Ankle-Foot Orthosis as a Diagnostic and Rehabilitation Tool for Gait

Authors:

Guillermo Asín, Filipe A. Barroso, Juan C. Moreno and José L. Pons

Abstract: A unilateral powered exoskeleton (Motorized ankle-foot orthosis, MAFO) is presented in this work, with the aim of studying muscle and kinematics short-term adaptations of the ankle during rehabilitation tasks. For this purpose, we conducted this study during gait over a treadmill, measuring surface electromyography activation and biomechanical data, in different conditions of assistance. This pilot study also aims to demonstrate that the tool is suitable for measuring biomechanical data while allowing EMG measurements, proving it as a useful tool during gait assessment and rehabilitation. Gastrocnemius Medialis activation presents slightly higher amplitude with higher assistances, so the subjects performed a higher range of motion gait pattern. Tibialis Anterior EMG activation presents consistent data with previous studies. Ankle angle at lower assistances makes the robot force less the subject to reach the imposed gait pattern, and so the range of motion diminishes. Regarding ankle angular velocity, at higher assistances, higher velocities are reached. The torque between the subjects foot and the robot. For lower assistances, the imposed reference pattern is less restrictive, and so the force the user exerts against the robot is lower.

Paper Nr: 4
Title:

Error Augmented Robotic Rehabilitation of the Upper Limb - A Review

Authors:

Aris C. Alexoulis-Chrysovergis, Andrew Weightman, Emma Hodson-Tole and Frederik J. A. Deconinck

Abstract: Objective: To collect and assess the available evidence for the efficacy of error augmentation in upper limb robotic rehabilitation. Methods: A systematic literature search up to May 2013 was conducted in one citation index, the Web of Knowledge, and in two individual databases: PubMed and Scopus, for publications that utilized error augmented feedback as practice modality in robotic rehabilitation of the upper limb. Results: The systematic search returned 12 studies that utilized error augmented feedback in trials to unimpaired and impaired individuals suffering from stroke, multiple sclerosis and primary dystonia. One additional study utilizing viscous force fields was included as the authors paid special merit to the effects of the field in directions where the error was amplified. In the studies that met the inclusion criteria two different types of error augmented feedback was used that is, haptic and visual feedback which were used either separately as rehabilitation modalities or in conjunction with each other. All studies but one report positive outcome regardless of the type(s) of feedback utilized. Conclusions: Error augmentation in upper limb robotic rehabilitation is a relatively new area of study, counting almost nine years after the first relevant publication and rather understudied. Error augmentation in upper limb robotic rehabilitation should be further researched in more practice-intensive studies and with larger trial groups. The potential of error augmented upper limb rehabilitation should also be explored with conditions other than the ones described in this review.