R. Jailani

Development of Dynamic Muscle Model with Functional Electrical Stimulation

This paper presents the development of paraplegic muscle model with Adaptive Neuro-Fuzzy Inference System (ANFIS). A series of experiments using Functional Electrical Stimulation (FES) with different stimulation frequencies, pulse width and pulse duration to investigate the impact on muscle output torque are conducted. The data that is obtained is used to develop the paraplegic muscle model. 500 training data and 300 testing data set are used in the development of muscle model. The muscle model thus developed is validated with clinical data from one paraplegic subject and in comparison with two other muscle models from previous researchers. The ANFIS muscle model is found to be the most accurate muscle model representing paraplegic muscle model. The established model is then used to predict the behaviour of the underlying system and will be used in the future for the design and evaluation of various control strategies.

Finite State Control of FES-Assisted Walking with Spring Brake Orthosis

This paper presents finite state control (FSC) of paraplegic walking with wheel walker using functional electrical stimulation (FES) with spring brake orthosis (SBO). The work is a first effort towards restoring natural like swing phase in paraplegic gait through a new hybrid orthosis, referred to as spring brake orthosis (SBO). This mechanism simplifies the control task and results in smooth motion and more-natural like trajectory produced by the flexion reflex for gait in spinal cord injured subjects. The study is carried out with a model of humanoid with wheel walker using the Visual Nastran (Vn4D) dynamic simulation software. Stimulated muscle model of quadriceps is developed for knee extension. Fuzzy logic control (FLC) is developed in Matlab/Simulink to regulate the muscle stimulation pulse-width required to drive FES-assisted walking gait and the computed motion is visualised in graphic animation from Vn4D and finite state control is used to control the transaction between all walking states. Finite state control (FSC) is used to control the switching of brakes, FES and spring during walking cycle.

Fuzzy modelling of knee joint with genetic optimization

Modelling of joint properties of lower limbs in people with spinal cord injury is significantly challenging for researchers due to the complexity of the system. The objective of this study is to develop a knee joint model capable of relating electrical parameters to dynamic joint torque as well as knee angle for functional electrical stimulation application. The joint model consists of a segmental dynamic, time-invariant passive properties and uncertain time-variant active properties. The knee joint model structure comprising optimised equations of motion and fuzzy models to represent the passive viscoelasticity and active muscle properties is formulated. The model thus formulated is optimised using genetic optimization, and validated against experimental data. The developed model can be used for simulation of joint movements as well as for control development. The results show that the model developed gives an accurate dynamic characterisation of the knee joint.

Effect of Inclined Rowing Machine on FES-Assisted Indoor Rowing Exercise Performance

This paper describes the effect of inclined track in an indoor rowing machine on the rowing exercise for paraplegics. The indoor rowing exercise is introduced as a total body exercise for rehabilitation of function of lower extremities through the application of functional electrical stimulation (FES). A model of the machine is developed using the Visual Nastran (Vn4D) software environment. Nine different degrees of inclination are set. Fuzzy logic control is implemented to control the knee and elbow trajectories for each of the inclination angle. The generated level of electrical stimulations for activation of quadriceps and hamstrings muscles are recorded and analysed. The results show that the highest efficiency is achieved at 7° of inclination. In view of good results obtained, it is concluded that different angles of track inclination significantly affect the level of electrical stimulation required to assist paraplegics’ indoor rowing exercise.

Estimation of Passive Stiffness and Viscosity in Paraplegic: A Dynamic Leg Model in Visual Nastran

Abstract This paper presents investigations into pendulum test to measure passive knee motion from a paraplegic subject. The test is used to evaluate changes in the knee angular displacement, passive stiffness and viscosity. Then, genetic algorithm (GA) parameter optimization is used with Visual Nastran (Vn4D) to find passive stiffness and viscosity values for modelling the paraplegic leg. The best performance of the Vn4D leg model is achieved with the optimum values of the viscosity and the stiffness equal to 0.0031055 Nms/deg and 0.024244 Nm/deg respectively. The model was found to be the best Vn4D model with actual subjects leg properties to represent paraplegic leg model.

PID Control of Knee Extension for FES-Assisted Walking with Spring Brake Orthosis

This paper presents a simulation of bipedal locomotion to control the stimulation pulses of functional electrical stimulation (FES) for activating muscles for paraplegic walking with spring brake orthosis (SBO). The work is a first effort towards restoring natural like swing phase in paraplegic gait through a new hybrid orthosis, referred to as spring brake orthosis (SBO). This mechanism simplifies the control task and results in smooth motion and more-natural like trajectory produced by the flexion reflex for gait in spinal cord injured subjects. The study is carried out with a model of humanoid with wheel walker using the Visual Nastran (Vn4D) dynamic simulation software. Stimulated muscle model of quadriceps is developed for knee extension. Proportional integral derivative (PID) control is developed in Matlab/Simulink to regulate the muscle stimulation pulse-width required to drive FES-assisted walking gait and the computed motion is visualised in graphic animation from Vn4D. The results show that SBO can reduce torque and stimulation pulses required for FES-assisted paraplegic walking with wheel walker and PID control is found to be appropriate controller for the leg extension.

Fuzzy logic control of knee extension for FES-assisted walking with spring brake orthosis

This paper presents a simulation of bipedal locomotion to control the stimulation pulses of functional electrical stimulation (FES) for activating muscles for paraplegic walking with spring brake orthosis (SBO). The work is a first effort towards restoring natural like swing phase in paraplegic gait through a new hybrid orthosis, referred to as spring brake orthosis (SBO). This mechanism simplifies the control task and results in smooth motion and more-natural like trajectory produced by the flexion reflex for gait in spinal cord injured subjects. The study is carried out with a model of humanoid with wheel walker using the Visual Nastran (Vn4D) dynamic simulation software. Stimulated muscle model of quadriceps is developed for knee extension. Fuzzy logic control (FLC) is developed in Matlab/Simulink to regulate the muscle stimulation pulse-width required to drive FES-assisted walking gait and the computed motion is visualised in graphic animation from Vn4D. The results show that SBO can reduce torque and stimulation pulses required for FES-assisted paraplegic walking with wheel walker and FLC is found to be appropriate controller for the leg extension.

Parameter Optimization of FES-Assisted Indoor Rowing Exercise Using MOGA

This paper describes the parameter optimization of fuzzy logic control (FLC) of FES-assisted indoor rowing exercise (FES-rowing) using multi objective genetic algorithm (MOGA). The indoor rowing exercise is introduced as a total body exercise for rehabilitation of function of lower extremities through the application of functional electrical stimulation (FES). FLC is used to control the knee and elbow trajectories for smooth rowing manoeuvre. MOGA is implemented in Matlab with a dynamic simulation model of indoor rowing exercise is developed using Visual Nastran (vN4D) software environment. MOGA is used to optimize the FES-rowing with two objective functions specified that are i) to minimize the mean squared error of knee angle trajectory and ii) to minimize the total electrical stimulation required by the muscles. In view of good results obtained, it is concluded that MOGA is able to obtain the optimal design of FLC for FES-rowing with two conflicting objectives.

Poster:Development of dynamic leg joint model for paraplegic with Functional Electrical Stimulation

This paper presents the development of paraplegic joint model using Artificial Neural Network (ANN). A series of experiments using Functional Electrical Stimulation (FES) with different stimulation frequencies, pulse width and pulse duration to investigate the impact on the leg swing angle is conducted. The data obtained is used to develop the paraplegic leg joint model. 74810 training data and 33602 testing data set are used in the development of joint model. The joint model thus developed is validated with clinical data from one paraplegic subject. Two modelling strategies were used to model the leg joint which the ANN joint model is found to be the most useful joint model representing paraplegic leg. The established model is then used to predict the behaviour of the underlying system and will be used in the future for the design and evaluation of various control strategies.

The Effectiveness of Body Weight Transfer in FES-Assisted Walking with Wheel Walker

This paper describes the development of a fuzzy control scheme for functional electrical stimulation, (FES)-assisted paraplegic walking with wheel walker. The simulation in this study starts with a model of humanoid with wheel walker using the Visual Nastran (Vn4D) dynamic simulation software. The humanoid model is designed based on anthropometric data. Two stimulated muscle models, quadriceps and hamstrings, are developed for knee extension and flexion. A fuzzy logic controller is designed to control the walking gait. It is designed in Matlab/Simulink to regulate the muscle stimulation pulse width required to drive FES-assisted walking gait. The body weight transfer technique is introduced to improve the paraplegic walking performance. The results show that body weight transfer can reduce torque required for FES-assisted paraplegic walking with wheel walker.