Trajectory Generation for a Lower Limb Exoskeleton for Sit-to-Stand Transition Using a Genetic Algorithm

2017 ◽  
Author(s):  
Ameya S. Chamnikar ◽  
Gaurav Patil ◽  
Mohammadreza Radmanesh ◽  
Manish Kumar
Keyword(s):  
Genetic Algorithm ◽  
Lower Limb ◽  
Degrees Of Freedom ◽  
Fitness Function ◽  
Trajectory Generation ◽  
The Body ◽  
Assistive Device ◽  
Reference Trajectory ◽  
Lower Limb Exoskeleton ◽  
Sit To Stand

Population of the world above the age of 65 years is increasing rapidly. Aging causes weakening of human joints which increases constraints on mobility of the body. Sit-to-Stand (STS), an important part of Activities of Daily Living (ADL) is one of the motions that is affected because of weakened joints. With the lack of personal care there is going to be a need for devices which can assist the aging population in STS. We propose the use of a lower-limb exoskeleton as an assistive device. One of the main challenges in this area is to generate a human like reference trajectory for exoskeleton to follow. This paper proposes the use of Genetic Algorithm (GA), to generate reference trajectories for the joint angles for lower limb exoskeleton for STS transition. The fitness function for the GA presented here is constructed based on the fact that for a successful STS center of mass (COM) needs to stay in the area of support. After the trajectory generation a simple controller is proposed to control a 3 degrees of freedom exoskeleton. The dynamics of the system being controlled are modelled as an inverse 3 degrees of freedom pendulum and the equations are derived using the Euler-Lagrange equation. The highly non-linear dynamics are linearized using an input-output feedback linearization technique. A PD controller is presented for this linearized dynamic system and the validation of the controller is done using simulations. Simulation results show that GA successfully generates a human like trajectory which eliminates the need to use motion tracking system for measuring human trajectories.

scholarly journals Simulating human–machine coupled model for gait trajectory optimization of the lower limb exoskeleton system based on genetic algorithm

2020 ◽  
Vol 17 (1) ◽  
pp. 172988141989349
Author(s):  
Bin Ren ◽  
Jianwei Liu ◽  
Jiayu Chen
Keyword(s):  
Genetic Algorithm ◽  
Lower Limb ◽  
Trajectory Optimization ◽  
Physical Simulation ◽  
Trajectory Generation ◽  
Coupled Model ◽  
Human Motion ◽  
Machine Model ◽  
Lower Limb Exoskeleton ◽  
Simulation Engine

The lower limb exoskeleton robot is capable of providing assisted walking and enhancing exercise ability of humans. The coupling human–machine model has attracted a lot of research efforts to solve the complex dynamics and nonlinearity within the system. This study focuses on an approach of gait trajectory optimization of lower limb exoskeleton coupled with human through genetic algorithm. The human–machine coupling system is studied in this article through multibody virtual simulation environment. Planning of the motion trajectory is carried out by the genetic algorithm, which is iteratively generated under optimization of a set of specially designed fitness functions. Human motion captured data are used to guide the evolution of gait trajectory generation method based on genetic algorithm. Experiments are carried out using the MATLAB/Simulink Multibody physical simulation engine and genetic algorithm-toolbox to generate a more natural gait trajectory, the results show that the proposed gait trajectory generation method can provide an anthropomorphic gait for lower limb exoskeleton device.

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.

Investigation of Human Locomotion With a Powered Lower Limb Exoskeleton

2021 ◽  
pp. 233-254
Author(s):  
Sergey Fedorovich Jatsun ◽  
Andrey Yatsun ◽  
Sergei Savin
Keyword(s):  
Lower Limb ◽  
Pressure Sensors ◽  
Human Locomotion ◽  
Sensor System ◽  
Assistive Device ◽  
Supporting Surface ◽  
Lower Limb Exoskeleton ◽  
Contact Points ◽  
Human Ability

In this chapter, the lower limb exoskeleton is studied. The roles of the exoskeleton both as a measurement device for studying human locomotion and as an assistive device that restores the human ability to walk are discussed. Particular attention is given to the investigation of the role of the pressure sensors and other devices that allow us to measure normal reactions at the contact points with the supporting surface and also detect these contacts. The way the geometry of the supporting surface affects the sensors system of the robot is considered, and new designs for feet sensor system are proposed. These include elastic foot, a foot with actuated sensors, and a foot with spring-damper systems.

scholarly journals Robust nonsingular fast terminal sliding-mode control for Sit-to-Stand task using a mobile lower limb exoskeleton

2020 ◽  
Vol 101 ◽  
pp. 104496 ◽  
Author(s):  
Joel Hernández Hernández ◽  
Sergio Salazar Cruz ◽  
Ricardo López-Gutiérrez ◽  
Arturo González-Mendoza ◽  
Rogelio Lozano
Keyword(s):  
Sliding Mode Control ◽  
Lower Limb ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Lower Limb Exoskeleton ◽  
Mode Control ◽  
Sit To Stand ◽  
Fast Terminal Sliding Mode

Three-dimensional modelling of wheelchair contrived with lower limb exoskeleton for right hemiplegic dysfunction

2020 ◽  
Vol 234 (7) ◽  
pp. 651-659
Author(s):  
AN Nithyaa ◽  
S Poonguzhali ◽  
N Vigneshwari
Keyword(s):  
Lower Limb ◽  
Computer Aided Design ◽  
Age Groups ◽  
Three Dimensional ◽  
The Body ◽  
Three Dimensional Model ◽  
Design Quality ◽  
Lower Limb Exoskeleton ◽  
Repeated Exercise ◽  
Aided Design

Hemiplegia is a type of paralysis that affects one side of the body due to stroke, characterizing severe weakness or rigid movement. Many people of different age groups are affected by this condition which cannot be completely cured but can be minimized through proper physiotherapy. A continuous and repeated exercise has to be given to the hemiplegic subjects to regain their motor function. To serve this purpose, a three-dimensional model of wheelchair contrived with lower limb exoskeleton is designed and motion analysis is done using SolidWorks. This virtual model of the object is created with the assistance of computer-aided design software. Professionals can be able to do the experiment on what-if scenarios with their three-dimensional designs, which helps to validate their devices and identify any snags with design quality. The pattern of behaviour of lower limb exoskeleton is predicted using SimMechanics in MATLAB.

Investigation of Human Locomotion With a Powered Lower Limb Exoskeleton

2018 ◽  
pp. 26-47 ◽  
Author(s):  
Sergey Fedorovich Jatsun ◽  
Andrey Yatsun ◽  
Sergei Savin
Keyword(s):  
Lower Limb ◽  
Pressure Sensors ◽  
Human Locomotion ◽  
Sensor System ◽  
Assistive Device ◽  
Supporting Surface ◽  
Lower Limb Exoskeleton ◽  
Contact Points ◽  
Human Ability

In this chapter, the lower limb exoskeleton is studied. The roles of the exoskeleton both as a measurement device for studying human locomotion and as an assistive device that restores the human ability to walk are discussed. Particular attention is given to the investigation of the role of the pressure sensors and other devices that allow us to measure normal reactions at the contact points with the supporting surface and also detect these contacts. The way the geometry of the supporting surface affects the sensors system of the robot is considered, and new designs for feet sensor system are proposed. These include elastic foot, a foot with actuated sensors, and a foot with spring-damper systems.

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