Papers by Prashant Jamwal
Journal of Intelligent and Fuzzy Systems, Aug 13, 2016
Robotic devices can be potentially used to assist physical therapy treatments in order to restore... more Robotic devices can be potentially used to assist physical therapy treatments in order to restore musculoskeletal system malfunctions owing to neurological disorders. Cable actuated parallel robots, despite their obvious benefits such as enhanced workspace, light weight, and flexibility, are not popularly used in ankle rehabilitation treatments, due to their complex mechanism and cable actuation issues. In order to address these issues, it is recommended to carry out robot design optimization. However, design synthesis of the cable actuated parallel ankle robot calls for multi-objective optimization (MOO), since there are multiple and conflicting objectives to achieve. To acquire more choices between actuator forces, overall stiffness of robot (which is crucial for a cable based ankle robot) and other vital design objectives, it is required to explore the extreme ends of the Pareto Front (PF) more carefully. Existing multi-objective evolutionary algorithms (MOEAs) normally focus on the convergence and may not provide solutions at the extremities of PF. Capitalizing on this improvement opportunity, this paper presents a fuzzy based MOEA, namely, biased fuzzy sorting genetic algorithm (BFSGA) which encourages solutions in the extreme zones of the PF. It is shown in this paper that using proposed method, diversity in the populations is supported and in the process wider trade-off choices of objectives can be obtained. During ankle robot design optimization, crisp objectives are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS). Subsequently OAS is used to assign a fuzzy dominance ranking to the design solutions. It is found that the BFSGA approach performs well in exploring the extreme zones of the Pareto front, which are normally overlooked by other MOEA such as NSGA-II due to their inherent mechanism.
International Symposium on Robotics, 2008
Mathematical Biosciences and Engineering, 2020
The present research envisages a novel group decision making model to evaluate the operational ri... more The present research envisages a novel group decision making model to evaluate the operational risk of airports from four aspects of human, equipment, management and environment factors. The proposed model featured an integration of intuitionistic fuzzy set and set pair analysis. Due to the lack of the systematic data and quantitative analysis concerning the uncertainty of these indicators, an intuitionistic fuzzy set was used to characterize them, which converted them into the ternary connection numbers based on set pair analysis. A new distance based on the intuitionistic fuzzy set and set pair analysis was proposed to analyze the consistency degree of any two experts on the same airport operation risk, wherein the degree of contact determined both the uncertainty and certainty of each indicator, so as to obtain the ranking degree of the expert group on the operation risk of all airports. Moreover, the relationship between the value of these indicators and the threshold changes of the airport operation risk ranking was evaluated. This study could be used as an effective tool for transit authorities to rank the operational risk of different airports, by comprehensively considering the viewpoint deviation of different decision makers on the same scheme, and its uncertainty factors. The analysis of the case study comprising four airports in China showed that with an increase in the degree of contact, the operation risk value of the airport in Beijing remained the same that of Tianjin and Qinhuangdao decreased, and for Shijiazhuang gradually increased.
Proceedings Of The Institution Of Mechanical Engineers, Part H: Journal Of Engineering In Medicine, Oct 24, 2017
There is an increasing research interest in exploring use of robotic devices for the physical the... more There is an increasing research interest in exploring use of robotic devices for the physical therapy of patients suffering from stroke and spinal cord injuries. Rehabilitation of patients suffering from ankle joint dysfunctions such as drop foot is vital and therefore has called for the development of newer robotic devices. Several robotic orthoses and parallel ankle robots have been developed during the last two decades to augment the conventional ankle physical therapy of patients. A comprehensive review of these robotic ankle rehabilitation devices is presented in this article. Recent developments in the mechanism design, actuation and control are discussed. The study encompasses robotic devices for treadmill and over-ground training as well as platform-based parallel ankle robots. Control strategies for these robotic devices are deliberated in detail with an emphasis on the assist-as-needed training strategies. Experimental evaluations of the mechanism designs and various control strategies of these robotic ankle rehabilitation devices are also presented.
Electric Power Systems Research, Aug 1, 2023
In this paper, a detailed mathematical modeling of non-ideal Ultra-lift Luo Converter (ULLC) is p... more In this paper, a detailed mathematical modeling of non-ideal Ultra-lift Luo Converter (ULLC) is presented by considering all the parasitics of the energy storing elements. The analysis is performed using Leverrier's algorithm in conjunction with the state-space averaging modeling method. The ULLC exhibits very high voltage gain capability, combining both the voltage gain of elementary and super-lift type luo converter. Further, the control to output transfer function and input to output transfer function are analyzed for both ideal and non-ideal scenarios. Besides, frequency response analysis is performed to prove the control stability of the same. Finally, it is believed that the reported findings could be of some assistance to the readers in providing a step-by-step procedure to analyze the steady-state and transient behaviour of ULLC converter under non-idealities and presence of parasitics.
Journal of Computational Design and Engineering, Nov 11, 2021
Neuroplasticity allows the human nervous system to adapt and relearn motor control following stro... more Neuroplasticity allows the human nervous system to adapt and relearn motor control following stroke. Rehabilitation therapy, which enhances neuroplasticity, can be made more effective if assisted by robotic tools. In this paper, a novel 4-SPS parallel robot has been developed to provide recovery of wrist movements post-stroke. The novel mechanism presented here was inspired by the forearm anatomy and can provide the rotational degrees of freedom required for all wrist movements. The robot design has been discussed in detail along with the necessary constructional, kinematic, and static analyses. The spatial workspace of the robot is estimated considering various dimensional and application-specific constraints besides checking for singular configurations. The wrist robot has been further evaluated using important performance indices such as condition number, actuator forces, and stiffness. The pneumatic artificial muscles exhibit varying stiffness, and therefore, workspace points are reached with different overall stiffness of the robot. It is essential to assess robot workspace points that can be reached with positive forces in actuators while maintaining a positive definite overall stiffness matrix. After the above analysis, design optimization has been carried out using an evolutionary algorithm whereby three critical criteria are optimized simultaneously for optimal wrist robot design.
Expert Review of Neurotherapeutics, Nov 16, 2020
Introduction: Robot-assisted neuro-rehabilitation is gaining acceptability among the physical the... more Introduction: Robot-assisted neuro-rehabilitation is gaining acceptability among the physical therapy community. The ankle is one of the most complicated anatomical joints in the human body and neurologic injuries such as stroke often result in ankle and foot disabilities. Areas covered: Robotic solutions for the ankle joint physical therapy have extensively been researched. Significant research has been conducted on the mechanism design, actuation as well as control of these ankle rehabilitation robots. Also, the experimental evaluations of these robots have been conducted with healthy and neurologically impaired subjects. This paper presents a comprehensive review of the recent developments in the field of robot-assisted ankle rehabilitation. Mechanism design, actuation, and various types of control strategies are discussed. Also, the experimental evaluations of these ankle rehabilitation robots are discussed in the context of the evaluation of robotic hardware with healthy subjects as well as motor function outcomes with neurologically impaired subjects. Expert opinion: Significant progress in the mechanism design, control, and experimental evaluations of the ankle rehabilitation robots have been reported. However, more sensing and reference trajectory generation methods need to be developed as well as more objective quantitive evaluations that need to be conducted for establishing the clinical significance of these robots.
Clinical Biomechanics, May 1, 2017
Background: A musculoskeletal model for the ankle complex is vital in order to enhance the unders... more Background: A musculoskeletal model for the ankle complex is vital in order to enhance the understanding of neuro-mechanical control of ankle motions, diagnose ankle disorders and assess subsequent treatments. Motions at the human ankle and foot, however, are complex due to simultaneous movements at the two joints namely, the ankle joint and the subtalar joint. The musculoskeletal elements at the ankle complex, such as ligaments, muscles and tendons, have intricate arrangements and exhibit transient and nonlinear behaviour. Methods: This paper develops a musculoskeletal model of the ankle complex considering the biaxial ankle structure. The model provides estimates of overall mechanical characteristics (motion and moments) of ankle complex through consideration of forces applied along ligaments and muscle-tendon units. The dynamics of the ankle complex and its surrounding ligaments and muscle-tendon units is modelled and formulated into a state space model to facilitate simulations. A graphical user interface is also developed during this research in order to include the visual anatomical information by converting it to quantitative information on coordinates. Findings: Validation of the ankle model was carried out by comparing its outputs with those published in literature as well as with experimental data obtained from an existing parallel ankle rehabilitation robot. Interpretation: Qualitative agreement was observed between the model and measured data for both, the passive and active ankle motions during trials in terms of displacements and moments. Keywords-Ankle joint, musculoskeletal model, joint moments, parallel ankle robots. NDERSTANDING the mechanical properties of the human ankle musculoskeletal system is important for simulating human movements, in the study of multi-joint U
IEEE Journal of Biomedical and Health Informatics, Mar 1, 2013
Cadence or stride frequency is an important parameter being controlled in gait training of neurol... more Cadence or stride frequency is an important parameter being controlled in gait training of neurologically impaired subjects. The aim of this study was to examine the effects of cadence variation on muscle activation patterns during robot assisted unimpaired gait using dynamic simulations. A twodimensional (2-D) musculoskeletal model of human gait was developed considering eight major muscle groups along with existing ground contact force (GCF) model. A 2-D model of a robotic orthosis was also developed which provides actuation to the hip, knee and ankle joints in the sagittal plane to guide subjects limbs on reference trajectories. A custom inverse dynamics algorithm was used along with a quadratic minimization algorithm to obtain a feasible set of muscle activation patterns. Predicted patterns of muscle activations during slow, natural and fast cadence were compared and the mean muscle activations were found to be increasing with an increase in cadence. The proposed dynamic simulation provide important insight into the muscle activation variations with change in cadence during robot assisted gait and provide the basis for investigating the influence of cadence regulation on neuromuscular parameters of interest during robot assisted gait.
IEEE Access, 2020
The number of older people is growing rapidly around the world. Ageing process results in reduced... more The number of older people is growing rapidly around the world. Ageing process results in reduced or restricted mobility which is essential to perform activities of daily living. Currently, there are numerous powered assistive exoskeletons commercially available as well as are being developed to support and rehabilitate lower limbs. Significant attention is also been given to develop upper limb rehabilitation devices, however the question of what kind of assistive devices can be used by elderly group of people for their upper limbs and what technical characteristics they should incorporate is not properly researched. This paper presents the state of the art of currently available assistive exoskeletons which can be exploited to support the motions of upper limbs of elderly to perform activities of daily living. Mechanism type, degrees of freedom, type actuators and materials selected for the fabrication of these porotypes are presented in detail. Also, the type of control systems utilized for these upper limb exoskeletons are discussed in detail with the insight on the feedback signal methods. A detailed discussion on the challenges in the fields of mechanism development, actuation and control for these upper limb powered exoskeletons is presented with the opportunities for future technological developments.
Journal of Cleaner Production, May 1, 2018
Highlights: 1. Production of synthetic zeolites derived from coal fly ash 2. Effect of the proces... more Highlights: 1. Production of synthetic zeolites derived from coal fly ash 2. Effect of the process parameters on conversion into zeolites 3. Heuristic approach of production optimization 4. Fuzzy modeling as an effective system architecture
IEEE Transactions on Automation Science and Engineering, Oct 1, 2015
This paper describes the design analysis and optimization of a novel 3-degrees of freedom (dof) w... more This paper describes the design analysis and optimization of a novel 3-degrees of freedom (dof) wearable parallel robot developed for ankle rehabilitation treatments. To address the challenges arising from the use of parallel mechanism, flexible actuators and the constraints imposed by the ankle rehabilitation treatment, a complete robot design analysis is performed. Three design stages of the robot, namely, kinematic design, actuation design and structural design are identified and investigated and in the process six important performance objectives are identified which are vital to achieve design goals. Initially the optimization is performed by considering only a single objective. Further analysis revealed that some of these objectives are conflicting and hence these are required to be simultaneously optimized. To investigate a further improvement in the optimal values of design objectives, a preference based approach and evolutionary algorithm based non-dominated sorting algorithm (NSGA II) are adapted to the present design optimization problem. Results from NSGA II are compared with the results obtained from the single objective optimization and preference based optimization approaches. It is found that NSGA II is able to provide better design solutions and is adequate to optimize all the objective functions concurrently. Finally, a fuzzy based ranking method has been devised and implemented in order to select the final design solution from the set of nondominated solutions obtained through NSGAII. The proposed design analysis of parallel robots together with the multiobjective optimization and subsequent fuzzy based ranking can be generalized with modest efforts for the development of all the classes of parallel robots.
IEEE Transactions on Industrial Electronics, Feb 1, 2017
It is a common hypothesis in the field of robot assisted gait rehabilitation that the active invo... more It is a common hypothesis in the field of robot assisted gait rehabilitation that the active involvement and voluntary participation of neurologically impaired subjects in the robotic gait training process may enhance the outcomes of such therapy. An adaptive seamless assist-as-needed (AAN) control scheme was developed for the robotic gait training. The AAN control scheme learns in real time the disability level of human subjects based on the trajectory tracking errors and adapts the robotic assistance accordingly. The overall AAN control architecture works on the basis of a robust adaptive control approach. The performance of seamless AAN control scheme was evaluated during treadmill training with a compliant robotic orthosis having 6degrees of freedom (DOF). Two experiments, namely trajectory following experiment and the AAN experiment were carried out to evaluate the performance of seamless adaptive AAN control scheme. It was found that the robotic orthosis is capable of guiding the subjects' limbs on reference trajectories during the trajectory following experiment. Also, a variation in robotic assistance was recorded during the AAN experiment based on the voluntary participation of human subjects. This work is an advance on the current state of the art in the compliant actuation of robotic gait rehabilitation orthoses in the context of seamless AAN gait training. Index Terms-Assist-as-needed, compliance adaptation, gait training, pneumatic muscle actuators, intrinsically compliant, robotic orthosis. I. INTRODUCTION EHABILITATION treatment of gait in patients suffering from neurologic impairments [1-3] such as stroke [4-6] and spinal cord injuries (SCI) can be significantly improved with the aid of robotic orthoses [7-9]. Active use
IEEE-ASME Transactions on Mechatronics, Feb 1, 2014
This paper presents the development of a novel adaptive wearable ankle robot for the treatments o... more This paper presents the development of a novel adaptive wearable ankle robot for the treatments of ankle sprain through physical rehabilitation. The ankle robot has a bioinspired design, devised after a careful study of the improvement opportunities in the existing ankle robots. Robot design is adaptable to subjects of varying physiological abilities and age groups. Ankle robot employs lightweight but powerful pneumatic muscle actuators (PMA) which mimics skeletal muscles in actuation. To address nonlinear characteristics of PMA, a fuzzy-based disturbance observer (FBDO) has been developed. Another instance of an adaptive fuzzy logic controller based on Mamdani inference has been developed and appended with the FBDO to compensate for the transient nature of the PMA. With the proposed control scheme, it is possible to simultaneously control four parallel actuators of the ankle robot and achieve three rotational degrees of freedom. To evaluate the robot design, the disturbance observer, and the adaptive fuzzy logic controller, experiments were performed. The ankle robot was used by a neurologically intact subject. The robot-human interaction was kept as active-passive while the robot was operated on predefined trajectories commonly adopted by the therapists. Trajectory tracking results are reported in the presence of an unpredicted human user intervention, use of compliant and nonlinear actuators, and parallel kinematic structure of the ankle robot.
International Journal of Intelligent Systems Technologies and Applications, 2021
A novel method for short-term load forecasting (STLF) is proposed in this paper. The method utili... more A novel method for short-term load forecasting (STLF) is proposed in this paper. The method utilizes both long and short data sequences which are fed to a wavenet based model that employs dilated causal residual convolutional neural network (CNN) and long short-term memory (LSTM) layer respectively to hourly forecast future load demand. This model is aimed to support the demand response program in hybrid energy systems, especially systems using renewable and fossil sources. In order to prove the generality of our model, two different datasets are used which are the ENTSO-E (European Network of Transmission System Operators for Electricity) dataset and ISO-NE (Independent System Operator New England) dataset. Moreover, two different ways of model testing are conducted. The first is testing with the dataset having identical distribution with validation data, while the second is testing with data having unknown distribution. The result shows that our proposed model outperforms other deep learning-based model in terms of root mean squared error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). In detail,
IEEE Transactions on Human-Machine Systems, Oct 1, 2020
While newer designs and control approaches are being proposed for rehabilitation robots, vital in... more While newer designs and control approaches are being proposed for rehabilitation robots, vital information from the human musculoskeletal system should also be considered. Incorporating knowledge about joint biomechanics during the development of robot controllers can enhance the safety and performance of robot-aided treatments. In the present work, the optimal path or trajectories of a parallel ankle rehabilitation robot were generated by minimizing joint reaction moments and the tension along ligaments and muscle-tendon units. The simulations showed that using optimized robot paths, user efforts could be reduced to 80%, thereby ensuring less strain on weaker or stiffer ligaments, etc. Additionally, to limit the moments applied by the robot in stiff or constrained directions, the intended robot path was modified to move the commanded position in the direction opposite to that of the position error. Such online modification of the robot path can lead to a reduction in forces applied by a robot to the subject. Simulation results and experimental findings with healthy subjects using an ankle rehabilitation robot prototype and subsequent statistical analysis further validated that path modification based on ankle joint biomechanics results in a reduction in undesired forces experienced by human users during treatment.
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Papers by Prashant Jamwal