Motion Planning of the Sit to Stand Movement for Powered Lower Limb Orthoses

2017 ◽  
Author(s):  
Octavio Narvaez-Aroche ◽  
Andrew Packard ◽  
Murat Arcak
Keyword(s):  
Lower Limb ◽  
Feedback Linearization ◽  
User Modeling ◽  
Center Of Mass ◽  
Angular Position ◽  
Control Allocation ◽  
Sit To Stand ◽  
Kinematic Behavior ◽  
Planar Robot ◽  
Reference Trajectories

We propose a generalizable strategy for planning the sit to stand movement of a powered lower limb orthosis and its user. Modeling the system as a three rigid link planar robot, we rely on its kinematic equations to obtain a set of transformations that allows us to compute reference trajectories for the angular positions of the links, starting from a desired kinematic behavior for the center of mass of the robot and the angular position of link 2 relative to link 1; as we consider them more suitable to define for achieving a safe sit to stand transition. We then proceed to design a tracking controller via feedback linearization and solve a constrained least-squares program to address the control allocation problem from including the loads applied by the arms of the user as inputs. We simulate two relevant STS movements to illustrate the system tracking the reference trajectories generated with our strategy, in the presence of parameter uncertainty.

scholarly journals Reachability Analysis for Robustness Evaluation of the Sit-to-Stand Movement for Powered Lower Limb Orthoses

2018 ◽  
Author(s):  
Octavio Narvaez-Aroche ◽  
Andrew Packard ◽  
Pierre-Jean Meyer ◽  
Murat Arcak
Keyword(s):  
Lower Limb ◽  
Center Of Mass ◽  
Linear Quadratic Regulator ◽  
The State ◽  
Reachable Sets ◽  
Linear Quadratic ◽  
Initial State ◽  
Worst Case ◽  
Sit To Stand ◽  
Finite Time Horizon

A sensitivity-based approach for computing over-approximations of reachable sets, in the presence of constant parameter uncertainty and a single initial state, is used to analyze a three-link planar robot modeling a Powered Lower Limb Orthosis and its user. Given the nature of the mappings relating the state and parameters of the system with the input, and output describing the trajectories of its Center of Mass, reachable sets for their respective spaces can be obtained relying on the sensitivities of the nonlinear closed-loop dynamics in the state space. These over-approximations are used to evaluate the worst-case performances of a finite time horizon linear-quadratic regulator for controlling the ascending phase of the Sit-To-Stand movement.

scholarly journals Effects of lower limb resistance exercise on muscle strength, physical fitness, and metabolism in pre-frail elderly patients: a randomized controlled trial

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaoxing Lai ◽  
Lin Bo ◽  
Hongwei Zhu ◽  
Baoyu Chen ◽  
Zhao Wu ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Resistance Exercise ◽  
Frail Elderly ◽  
Lower Limb ◽  
Intervention Group ◽  
Control Group ◽  
Walking Test ◽  
Sit To Stand ◽  
Femoris Muscle ◽  
Activity Energy

Abstract Background Few studies examined interventions in frail elderly in China, while the awareness of applying interventions to prevent frailty in pre-frail elderly is still lacking. This study aimed to explore the effects of lower limb resistance exercise in pre-frail elderly in China. Methods This was a randomized controlled trial of patients with pre-frailty. The control group received routine care, while the exercise group received a 12-week lower limb resistance exercise based on routine care. The muscle strength in the lower limbs, physical fitness, and energy metabolism of the patients was evaluated at admission and after 12 weeks of intervention. Results A total of 60 pre-frail elderly were included in this study. The patients were divided into the exercise group (n = 30) and control group (n = 30) by random grouping. There were 17 men and 13 women aged 65.3 ± 13.4 in the exercise group, and 15 men and 15 women aged 67.6 ± 11.9 years in the control groups. The Barthel index was 80.3 ± 10.6 and 85.1 ± 11.6, respectively. The characteristics of the two groups were not significantly different before intervention (all p > 0.05). The results of repeated measurement ANOVA showed that there was statistically significant in crossover effect of group * time (all p < 0.05), that is, the differences of quadriceps femoris muscle strength, 6-min walking test, 30-s sit-to-stand test, 8-ft “up & go” test, daily activity energy expenditure and metabolic equivalent between the intervention group and the control group changed with time, and the variation ranges were different. The main effects of time were statistically significant (all p < 0.05), namely, femoris muscle strength, 6-min walking test, 30-s sit-to-stand test, 8-ft “up & go” test, daily activity energy expenditure and metabolic equivalent of the intervention group and the control group were significantly different before and after intervention. The main effects of groups were statistically significant (p < 0.05), namely, femoris muscle strength, 6-min walking test, 30-s sit-to-stand test, daily activity energy expenditure and metabolic equivalent before and after intervention were significantly different between the intervention group and the control group, while there was no significant differences in 8-ft “up & go” test between groups. Conclusion Lower limb resistance exercise used for the frailty intervention could improve muscle strength, physical fitness, and metabolism in pre-frail elderly. Trial registration ChiCTR, ChiCTR2000031099. Registered 22 March 2020, http://www.chictr.org.cn/edit.aspx?pid=51221&htm=4

Improving sit-to-stand transition by the saddle-assistive device in the spinal cord injury: A case study

2021 ◽  
pp. 095441192110033
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Limb ◽  
Reaction Force ◽  
Assistive Device ◽  
Limb Weakness ◽  
Sit To Stand ◽  
Lower Limb Weakness ◽  
Wide Range ◽  
Cord Injury

Physical problems caused by fractures, aging, stroke, and accidents can reduce foot power; these, in the long term, can dwindle the muscles of the waist, thighs, and legs. These conditions provide the basis for the invalidism of the harmed people. In this study, a saddle-walker was designed and evaluated to help people suffering from spinal cord injury and patients with lower limb weakness. This S-AD works based on body weight support against the previously report designs. This saddle-walker consisted of a non-powered four-wheel walker helping to walk and a powered mechanism for the sit-to-stand (STS) transfer. A set of experiments were done on the STS in the use of the standard walker and the saddle-assistive device(S-AD). A comparison of the results showed that this device could reduce the vertical ground reaction force (GRF) of the legs up to 70%. Using this device could help a wide range of patients with lower limb weakness and SCI patients in changing from sitting to standing.

Application of Sit-To-Stand Assistive Device Based on Hip Support

2021 ◽  
Vol 14 ◽  
Author(s):  
Huaiqiang Zhang ◽  
Qiang Xue ◽  
Shuo Yang ◽  
Tongtong Wang ◽  
Binwei Zhou
Keyword(s):  
Lower Limb ◽  
Independent Living ◽  
Structural Characteristics ◽  
Assistive Devices ◽  
Assistive Device ◽  
Technology Application ◽  
Assist Devices ◽  
Advantages And Disadvantages ◽  
Sit To Stand

Background: Completing the transition from a sitting position to a standing position is a basic skill in people’s daily lives and is crucial for independent living. Lower limb dysfunction will bring many inconveniences into a person’s life and greatly affect their quality of life. Patients with lower limb dysfunction are a specialized group, and nursing problems for this group are becoming increasingly serious. Helping patients with lower limb dysfunction restore their lower limb mobility or assisting them to walk is a social problem necessary to be solved. Objective: : To review the recent sit-to-stand assistive devices based on hip support, classify them systematically and introduce their characteristics, including the mechanisms and the types of patients for which such mechanisms are applicable; to help patients with lower limb dysfunction or doctors (therapists) understand and choose a reasonable sit-to-stand assist device based on hip support. Methods: This paper summarizes literatures and patents about sit-to-stand assistive devices. From the aspects of structural characteristics, drive type and support modes based on the hip and applications situation, the advantages and disadvantages of the typical sit-to-stand assist devices are represented. Results: Current and future development trends on the structural characteristics, drive type and support modes based on the hip and applications situation of sit-to-stand assist devices are discussed to improve the humanization, modularization and applicability of sit-to-stand assist devices. Conclusion: Sit-to-stand assistive devices based on hip support can help patients improve the quality of their life, assist patients carrying out rehabilitation training, and delay the decline of lower limb function. However, the existing sit-to-stand assistive devices based on hip support need further improvement in the aspects of motion mechanism, new technology application and ergonomics design.

Modeling a Predictive Control of Human Locomotion Based on the Dynamic Behavior

2018 ◽  
pp. 316-331
Author(s):  
Joao Mauricio Rosario ◽  
Leonimer Flavio de Melo ◽  
Didier Dumur ◽  
Maria Makarov ◽  
Jessica Fernanda Pereira Zamaia ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Predictive Control ◽  
Lower Limb ◽  
Center Of Mass ◽  
Human Locomotion ◽  
Lower Limbs ◽  
Human Gait ◽  
Virtual Model ◽  
Dynamical Study ◽  
Continuous Dynamic

This chapter presents the development of a lower limb orthosis based on the continuous dynamic behavior and on the events presented on the human locomotion, when the legs alternate between different functions. A computational model was developed to approach the different functioning models related to the bipedal anthropomorphic gait. Lagrange modeling was used for events modeling the non-holonomic dynamics of the system. This chapter combines the comparison of the use of the predictive control based on dynamical study and the decoupling of the dynamical model, with auxiliary parallelograms, for locating the center of mass of the mechanism using springs in order to achieve the balancing of each leg. Virtual model was implemented and its kinematic and dynamic motion analyzed through simulation of an exoskeleton, aimed at lower limbs, for training and rehabilitation of the human gait, in which the dynamic model of anthropomorphic mechanism and predictive control architecture with robust control is already developed.

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