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.

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.

scholarly journals Mechanics and energetics of walking and running up and downhill: A joint-level perspective to guide design of lower-limb exoskeletons

2020 ◽  
Author(s):  
Richard W. Nuckols ◽  
Kota Z. Takahashi ◽  
Dominic J. Farris ◽  
Sarai Mizrachi ◽  
Raziel Riemer ◽  
...  
Keyword(s):  
Lower Limb ◽  
Gait Cycle ◽  
Human Locomotion ◽  
Mechanical Power ◽  
Joint Mechanics ◽  
Wearable Robot ◽  
Lower Limb Exoskeleton ◽  
Surface Gradient ◽  
Gait Phase ◽  
Robotic Devices

AbstractLower-limb wearable robotic devices can provide effective assistance to both clinical and healthy populations; however, how assistance should be applied in different gait conditions and environments is still unclear. We suggest a biologically-inspired approach derived from knowledge of human locomotion mechanics and energetics to establish a ‘roadmap’ for wearable robot design. In this study, we characterize the changes in joint mechanics during both walking and running across a range of incline/decline grades and then provide an analysis that informs the development of lower-limb exoskeletons capable of operating across a range of mechanical demands. Eight subjects (6M,2F) completed five walking (1.25 m -1) trials at −15%, −10%, 0%, 10%, and 15% grade and five running (2.25 m s-1) trials at −10%, −5%, 0%, 5%, and 10% grade on a treadmill. We calculated time-varying joint moment and power output for the ankle, knee, and hip. For each gait, we examined how individual limb-joints contributed to total limb positive, negative and net power across grades. For both walking and running, changes in grade caused a redistribution of joint mechanical power generation and absorption. From level to incline walking, the ankle’s contribution to limb positive power decreased from 44% on the level to 28% at 15% uphill grade (p < 0.0001) while the hip’s contribution increased from 27% to 52% (p < 0.0001). In running, regardless of the surface gradient, the ankle was consistently the dominant source of lower-limb positive mechanical power (47-55%). In the context of our results, we outline three distinct use-modes that could be emphasized in future lower-limb exoskeleton designs 1) Energy injection: adding positive work into the gait cycle, 2) Energy extraction: removing negative work from the gait cycle, and 3) Energy transfer: extracting energy in one gait phase and then injecting it in another phase (i.e., regenerative braking).

scholarly journals Terrain Feature Estimation Method for a Lower Limb Exoskeleton Using Kinematic Analysis and Center of Pressure

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4418 ◽  
Author(s):  
Myounghoon Shim ◽  
Jong In Han ◽  
Ho Seon Choi ◽  
Seong Min Ha ◽  
Jung-Hoon Kim ◽  
...  
Keyword(s):  
Lower Limb ◽  
Kinematic Analysis ◽  
Center Of Pressure ◽  
Contact Point ◽  
Estimation Method ◽  
Least Square Method ◽  
Least Square ◽  
Estimation Accuracy ◽  
Lower Limb Exoskeleton ◽  
Contact Points

While controlling a lower limb exoskeleton providing walking assistance to wearers, the walking terrain is an important factor that should be considered for meeting performance and safety requirements. Therefore, we developed a method to estimate the slope and elevation using the contact points between the limb exoskeleton and ground. We used the center of pressure as a contact point on the ground and calculated the location of the contact points on the walking terrain based on kinematic analysis of the exoskeleton. Then, a set of contact points collected from each step during walking was modeled as the plane that represents the surface of the walking terrain through the least-square method. Finally, by comparing the normal vectors of the modeled planes for each step, features of the walking terrain were estimated. We analyzed the estimation accuracy of the proposed method through experiments on level ground, stairs, and a ramp. Classification using the estimated features showed recognition accuracy higher than 95% for all experimental motions. The proposed method approximately analyzed the movement of the exoskeleton on various terrains even though no prior information on the walking terrain was provided. The method can enable exoskeleton systems to actively assist walking in various environments.

Geriatric Walk Assist Robot - Design, Analysis and Implementation of a Modular Lower Limb Exoskeleton Robot

2016 ◽  
Vol 852 ◽  
pp. 770-775 ◽  
Author(s):  
P. Karthikeyan ◽  
Gopal Satheesh Kumar ◽  
M. Ajin
Keyword(s):  
Lower Limb ◽  
Control Algorithm ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Gait Pattern ◽  
The Body ◽  
Sensors And Actuators ◽  
Aged People ◽  
Lower Limb Exoskeleton ◽  
Exoskeleton Robot

Among the problems of major concern faced by the geriatric community the fore most is considered to be: “as we grow older it gets difficult to walk”. As they lose their strength to withstand their weight they become weak to walk on their own. Through this project a design is proposed for an assistive modular lower limb exoskeleton robot to enable aged people to walk on their own. The design is mainly based on the amplification of the pressure applied on the thighs and ankles of the legs and these pressures are used to move the legs of the robot which support the legs of the user. Since the user is capable of generating a minimum pressure on their own the working of the gait pattern is mainly based on the movement of knee and ankle, and so only the knee and the ankle are considered in this design. Another reason is that the major weight of the body acts on the knee and the foot while walking. The working of the robot is mainly based on the layered control algorithm embedded on the microcontroller acting through the sensors and actuators. Pressure sensors are used to measure the applied pressure and electrical actuators are used due to their lesser weight. Based on the experimental results obtained with the working robot the design would be fine-tuned for optimized performance.

Design of Passive Lower Limb Exoskeleton to Aid in Injury Mitigation and Muscular Efficiency

2020 ◽  
Author(s):  
Dylan Tracey ◽  
Hao Zhang
Keyword(s):  
Lower Limb ◽  
Stride Length ◽  
Human Locomotion ◽  
Running Economy ◽  
Lower Limbs ◽  
Stride Frequency ◽  
Load Variations ◽  
Lower Limb Exoskeleton ◽  
Viable Solution ◽  
The Impact

Abstract With the duties and responsibilities of the military, they are on the cutting edge of R&D and the latest and greatest technologies. One significant problem effecting thousands of soldiers are injuries to the lower limbs, specifically the knees, as a result of high impact to the joints and muscles. Through the research of biomechanics and ergonomics during human locomotion of running, cause and effects fatigue, muscular activation during running, gait cycle force analysis, and biomimicry of kangaroos, we were able to identify lower limb exoskeletons as a viable solution to the problem. The purpose of this research was to develop a relatively inexpensive prototype of a passive lower limb exoskeleton to aid in injury mitigation and muscular efficiency for soldiers. The hypothesis was that a lower limb exoskeleton would reduce/mitigate injuries by reducing stride length and increases stride frequency to lower impact on the knees while running. The prototype was tested by one participant on a 2-mile course with two load variations tested while running. The key results were seen from the spring systems potential to increase average stride cadence/frequency by 6–14% and reduce impact on joints and muscles by increasing the number of steps and reducing high center of gravity oscillation by 13–27%. Furthermore, this study provides evidence and research that proves that a passive lower limb exoskeleton design, which increases stride frequency and reduces stride length, can mitigate injuries to the lower limbs when running with weight by reducing the impact forces on the knees and improving running economy.

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.

Analysis of Human–Exoskeleton System Interaction for Ergonomic Design

2020 ◽  
pp. 001872082091378
Author(s):  
Yilin Wang ◽  
Jing Qiu ◽  
Hong Cheng ◽  
Xiaojuan Zheng
Keyword(s):  
Lower Limb ◽  
Pressure Sensors ◽  
Gait Training ◽  
Average Pressure ◽  
Interaction Forces ◽  
Lower Limb Exoskeleton ◽  
Pressure Threshold ◽  
Pain Pressure Threshold ◽  
Cord Injury ◽  
And Control

Objective Lower-limb exoskeleton systems are defined as gait training or walking-assisting devices for spinal cord injury or hemiplegic patients. Crutches, straps, and baffles are designed to protect subjects from falling. However, skin abrasions occur when the interaction forces are too large. In this study, the interaction forces between the human body and an exoskeleton system named the AIDER were measured to confirm whether the design was ergonomic. Background The AIDER system is a wearable lower-limb exoskeleton. It secures a subject by binding on the waist, thighs, shanks, and feet. Method Eight healthy subjects participated in the study. The interaction forces of the waist strap, thigh baffles, shank baffles, and crutch handles were measured by pressure sensors. Ten repetitions were completed in this study. After one repetition, custom comfort questionnaires were completed by the subjects. Results Although a few of the peak values of the maximum intensities of pressure between the hands and crutch handles reached the minimum value of the pain–pressure threshold (PPT), the average pressure intensities were much smaller than the PPT value. Conclusions The results indicated that the mechanical structure and control strategy of the AIDER must be improved to be more ergonomic in the future.

The role of delayed lower limb embolectomy in patients with late ischemia

Chirurgia ◽  
2020 ◽  
Vol 32 (6) ◽  
Author(s):  
Walid M. Gamal ◽  
Abdrheem F. Mohamed ◽  
Zeniab M. Askary
Keyword(s):  
Lower Limb
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