scholarly journals H-infinity Sliding Mode Controller Design for a Human Swing Leg System

2020 ◽  
Vol 23 (2) ◽  
pp. 117-126
Author(s):  
Hazem I. Ali ◽  
Azhar Jabbar Abdulridha
Keyword(s):  
Knee Joint ◽  
Hip Joint ◽  
Controller Design ◽  
Sliding Mode ◽  
Knee Joints ◽  
Upper Body ◽  
Double Pendulum ◽  
H Infinity ◽  
Dynamic Output Feedback Controller ◽  
Better Than

In this paper, the H-infinity Sliding Mode Control (HSMC) is designed to produce a new dynamic output feedback controller for trajectory tracking of the nonlinear human swing leg system. The human swing leg system represents the support of human leg or the humanoid robot leg which is usually modeled as a double pendulum. The thigh and shank of a human leg is represented by two pendulum links and the hip joint will connect the upper body to the thigh and the knee joint will connect the thigh to the shank. The external torques (servo motors) are applied at the hip and knee joints to move the muscles of thigh and shank. The results show that the HSMC can robustly stabilize the system and achieve a desirable time response specification better than if only H-infinity or SMC is used. This controller achieves the following specifications:  sec,  for hip joint and sec, for knee joint.

scholarly journals State Feedback Sliding Mode Controller Design for Human Swing Leg System

2018 ◽  
Vol 21 (1) ◽  
pp. 51 ◽  
Author(s):  
Hazem I. Ali ◽  
Azhar J. Abdulridha
Keyword(s):  
State Feedback ◽  
Humanoid Robot ◽  
Controller Design ◽  
Sliding Mode ◽  
Knee Joints ◽  
Upper Body ◽  
Double Pendulum ◽  
Robot Leg ◽  
Dynamic Output Feedback Controller ◽  
The Mathematical Model

In this paper, the robustness properties of sliding mode control (SMC) which is designed to produce a dynamic output feedback controller to achieve robustness for trajectory tracking of the nonlinear human swing leg system is presented. The human swing leg represents the support of human leg or the humanoid robot leg which is usually modeled as a double pendulum. The thigh and shank of a human leg will respect the pendulum links, hip and knee will connect the upper body to thigh and then shank respectively. The total moments required to move the muscles of thigh and shank are denoted by two external (servomotors) torques applied at the hip and knee joints. The mathematical model of the system is developed. The results show that the proposed controller can robustly stabilize the system and achieve a desirable time response specification.

Impulse and Moment of Impulse in the Leg Joints by Impact From Kicking

1983 ◽  
Vol 105 (2) ◽  
pp. 108-111 ◽  
Author(s):  
L. Lindbeck
Keyword(s):  
Theoretical Analysis ◽  
Knee Joint ◽  
Hip Joint ◽  
Lower Leg ◽  
Knee Joints ◽  
Double Pendulum ◽  
Additional Measurement ◽  
Impulsive Motion ◽  
Series Of Experiments ◽  
The Impact

In a previous paper we have given a theoretical analysis of the impulsive motion of the leg, modeled as a double pendulum. This analysis made it possible to estimate the impulsive reactions in the knee joint as a function of the measured initial and final velocities of the leg, when an impact was given to the lower leg, e.g., by means of a kick. This estimation was made under the assumption that no impulsive moments occur in the hip and the knee joints, i.e., that no muscles were stretched during the time of impact. In the present paper it is shown how such impulsive moments, should they occur, can be determined by means of an additional measurement, i.e., of the velocity of the ball after the impact. The results from a series of experiments are reported, showing that such impulsive moments in the joints occur in an appreciable number of the kicks, especially in the hip joint, indicating that muscles, acting on this joint, are prestressed during the impact.

Bending and Torsional Vibration Control of a Flexible Structure Using H-infinity Based Approach

1997 ◽  
Vol 9 (5) ◽  
pp. 387-392
Author(s):  
Indra N. Kar ◽  
◽  
Kazuto Seto
Keyword(s):  
Torsional Vibration ◽  
Controller Design ◽  
Design Method ◽  
Flexible Structure ◽  
Mass Model ◽  
H Infinity ◽  
Actuator Dynamics ◽  
Lumped Parameter ◽  
Dynamic Output Feedback Controller ◽  
Three Degree Of Freedom

This paper presents a method of controlling the bending and torsional vibration mode of a flexible structure using H-infinity optimal control. A new idea is proposed in order to reduce the unmodeled system uncertainties by placing actuators in the nodes of certain neglected vibration modes. Then, the controller is designed based on the reduced order model and is capable of attenuating vibration without causing spillover instability. For this purpose, a three degree of freedom lumped parameter mass model of a plate structure is considered to control its vibrations using a dynamic output feedback controller. The actuator dynamics and the placement of the actuators are considered for a effective controller design method. The efficacy of the controller is shown through simulations.

scholarly journals Clinical and microbiological characteristics of periprosthetic hip and knee infections

2020 ◽  
pp. 237-240
Author(s):  
Vladimir A. ​ Ivantsov ◽  
I.P. Bogdanovich ◽  
V.V. Lashkovskiy ◽  
V.S. Anosov
Keyword(s):  
Surgical Treatment ◽  
Knee Joint ◽  
Hip Joint ◽  
Joint Replacement ◽  
Periprosthetic Infection ◽  
Joint Infection ◽  
Knee Joints ◽  
Knee Joint Replacement ◽  
Hip Joint Replacement ◽  
Total Knee

Objective. To characterize periprosthetic joint infection in patients undergoing a total hip and knee joint replacement. Materials and Methods. A total of 77 patients with periprosthetic infection following hip and knee joint replacement hospitalized in Grodno City Clinical Hospital were studied over the period of 2014-2018. Wound discharge, tissue samples, and fistula’s wall swab were used for microbiological tests. The analysis of surgical treatment of patients with deep periprosthetic knee and hip joint infection has been performed. Results. Periprosthetic infection after hip joint arthroplasty was observed in 32 (41.6%) patients, and after total knee joint arthroplasty in 45 (58.4%) patients. Surgical treatment was performed in 18 (56.3%) and 32 (71.1%) patients with periprosthetic infection following total knee and hip joint replacement, respectively. A total of 10 (31.2%) of 32 cultures from patients with periprosthetic infection after total hip joint replacement and 8 (17.8%) of 45 cultures from patients with periprosthetic infection after total knee joint replacement were positive. Overall, Staphylococcus aureus was detected in 9 (50%) of 18 positive cultures. Gram-negative aerobic bacteria (Acinetobacter baumannii, Klebsiella pneumoniae Pseudomonas aeruginosa) were detected in 4⁄10 and 5⁄8 of positive cultures from patients with periprosthetic infection of hip and knee joints, respectively. Conclusions. The most common pathogens causing periprosthetic infection of hip and knee joints were S. aureus (50%) and Gram-negative bacteria. The surgical treatment was performed in 71.4% of patients with periprosthetic joint infection.

Development and Evaluation of a Mechanical Stance-Controlled Orthotic Knee Joint With Stance Flexion

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Jan Andrysek ◽  
Matthew J. Leineweber ◽  
Hankyu Lee
Keyword(s):  
Knee Joint ◽  
Controller Design ◽  
Control Strategies ◽  
Weight Bearing ◽  
Quadriceps Muscle ◽  
Swing Phase ◽  
Knee Joints ◽  
Stance Control ◽  
New Type

Stance-control orthotic knee joints stabilize the knee joint during the weight-bearing portion of gait without restricting swing-phase flexion, thus achieving a more normal gait for individuals with quadriceps muscle weakness. These devices must be designed around well-defined stance-control strategies that enable or hinder joint motion at specific events during the gait cycle. This paper presents a new type of stance-control strategy and a novel stance-controller design. Pilot clinical testing was performed on a prototype, demonstrating feasibility of this approach for providing reliable knee stability while facilitating swing-phase flexion. In particular, 44 deg of swing-phase flexion and 15 deg of stance-phase flexion were achieved during level walking. Further testing is needed in situ to provide additional validation and assess other mobility conditions.

Gait Generation for a Walking Robot with Passive Joints

2008 ◽  
Vol 20 (5) ◽  
pp. 785-792 ◽  
Author(s):  
Kazunori Kaede ◽  
◽  
Tooru Nogai ◽  
Keyword(s):  
Knee Joint ◽  
Hip Joint ◽  
Model Simulation ◽  
Knee Joints ◽  
Legged Robot ◽  
Walking Robot ◽  
Ankle Joints ◽  
Robot Behavior ◽  
Link Model ◽  
Input Torque

We selected a three-legged robot to study passive walking. The robot consists of one actuated leg and one pair of passive legs. The active leg has a knee joint and an ankle joint. The passive legs, which we call “crutches,” have no knee joints, but it do have passive ankle joints. The crutches and the leg are connected by a hip joint. The robot behavior is passive while it supports itself on its crutches and swings its leg. In order for the robot to have a wide stride and be stable after the leg swings out and lands, a referenced trajectory of the leg's swing is generated by a planar, four-link model simulation to evaluate its posture after the leg lands. The pattern of walking applies to the robot's actual walk on level ground. An additional walking robot that has a knee joint that is permitted to rotate freely has been designed. The lower leg is equipped with a solenoid magnet which keeps the knee joint straight. The knee joint bends and the leg swings in response to a change in the input torque to the hip joint.

Prediction, Control and Energy Analyses of Hydraulic Transformer Based Heave Compensator

2021 ◽  
Author(s):  
Huan Yu ◽  
Jinhui Fang ◽  
Jianhua Wei ◽  
Shizhen Li ◽  
Hangjun Zhang
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Ship Motion ◽  
Luenberger Observer ◽  
Hydraulic Transformer ◽  
Simulation Results ◽  
The One ◽  
Prediction Control ◽  
Wave Induced ◽  
Better Than

Abstract Heave compensators are widely used in offshore equipments to decouple the load motion from the wave induced ship motion. Hydraulic transformer based heave compensator (HTHC) can better compensate the ship’s heave in comparison with passive heave compensators (PHC) under changing sea conditions, meanwhile the accumulators’ volume is decreased significantly. Here in this paper, some further discussions about HTHC are given on the aspects of prediction, controller design and energy saving through simulation. Results turn out that heave prediction based on sliding mode observer is better than the Luenberger observer based one; chattering can be reduced through back-stepping method. The controller is robust when the load is perturbed by uncertain forces, and energy consumption of HTHC is about 56% of the one in an equal-sized hybrid active heave compensator (HAHC) meanwhile its total installed power can be reduced by 70%.

Effects of a Passive Dynamic Walker’s Mechanical Parameters on Foot-Ground Clearance

2014 ◽  
Vol 687-691 ◽  
pp. 279-284
Author(s):  
Xin Yu Liu ◽  
Xi Zhe Zang ◽  
Jie Zhao
Keyword(s):  
Stability Analysis ◽  
Numerical Simulations ◽  
Hip Joint ◽  
Parameters Optimization ◽  
Knee Joints ◽  
Upper Body ◽  
Mechanical Parameters ◽  
Human Beings ◽  
Ground Clearance ◽  
Ankle Joints

Unlike human beings, a robot will fall without a sufficient walking foot-ground clearance, which is essential to a success walking. However, to obtain less calculating time and simpler analysis, foot scuffing is ignored in most studies during numerical simulations of passive dynamic walkers which can walk down a gentle slope and are actuated only by their own gravity. So this paper initials a study on the effects of a passive dynamic walker’s mechanical parameters on foot-ground clearance and the results can be used to make a further parameters optimization based on walking stability analysis. A passive dynamic walking model with a hip joint, knee joints, ankle joints and an upper body and a prototype were built and numerical simulations were implemented to analyze the effects of mechanical parameters on foot-ground clearance. Finally, the results were validated in prototype experiments.

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