Bond Graph Technique Research Articles

Modeling and simulation of the kinematic behavior of the deployment mechanism of solar array for a 1‐U CubeSat

AbstractKinematics of deployable solar array mechanisms in CubeSat satellites have considerable influence on the stability and attitude control of a satellite, especially in low mass systems as CubeSats. One of the issues with the conventional solar panel deployment mechanisms in CubeSats is the speed of its deployment, especially when position‐lock to hold the panels back from oscillation is lacking. The generated oscillation becomes more pronounced in a system equipped with solar tracking unit and thus, reduces available projected area of the panels and causing fatigue at the yoke and panel hinges. This work aims at modeling and simulation of the 1‐U CubeSat solar panel deployment mechanism vibration control using fisher wire. Two‐fold panel deployment mechanism with a rolling sun‐tracking tilt mechanism was developed. The system performance from viewpoint of vibration analysis was evaluated using mass‐spring‐damper method and bond graph techniques. Numerical simulations and experiments were performed to validate the proposed method. The modeling and computational analysis were done with SOLIDWORKS software. The system was tested for vibration and stability using the seismic mass‐spring‐and‐damper arrangement to validate the model. A 3‐D printing was generated and tested to evaluate its vibration performance and its effects during deployment. The result was such that the two panels attached to a wing hinged at Y – and – Y directions deployed slowly and smoothly at approximately 2 s, giving room for the vibration to decay exponentially towards zero. This agrees with reported works where a DC motor was used to control speed of deployment by increasing time to 6.8 s. The simulated and experimental results of the printed model showed close agreement with the theoretical values with an error of 0.03% in energy supply reliability and up to 400% power generation potential when compared to body mounted solar panels with the same satellite specification without a significant impact on system strength and stability.

Sensor fault diagnosis for uncertain dissimilar redundant actuation system of more electric aircraft via bond graph and improved principal component analysis

This paper develops a sensor condition monitoring method integrating the model-based bond graph (BG) technique and data-driven principal component analysis (PCA) for the dissimilar redundant actuation system of more electric aircraft with uncertain parameters. The uncertain dissimilar redundant actuation system is modeled by BG in linear fractional transformation form. After that, the analytical redundancy relations containing the nominal part and the uncertain part can be derived, based on which the adaptive thresholds and the fault signature matrix (FSM) can be obtained for robust fault detection and fault isolation. To improve the fault isolation performance under the multiple faults condition, a new fault isolation method integrating FSM and improved PCA (IPCA) is developed, where the possible fault set generated from the FSM is further refined by the IPCA module with an improved reconstruction algorithm and cyclic PCA monitoring model to achieve a more efficient fault isolation result. The effectiveness of the proposed approach is validated by simulation investigations.

Robust control of a planar snake robot based on interval type-2 Takagi–Sugeno fuzzy control using genetic algorithm

This paper presents trajectory tracking control of a snake robot in the presence of system uncertainty such as disturbances and parameter uncertainties. First, we derive a realistic dynamic model of the snake robot in the framework of the bond graph technique. Next, we present an interval type-2 Takagi–Sugeno fuzzy proportional–derivative (IT2FPD) control scheme, whose parameters are tuned using a genetic algorithm (GA) optimization approach. An improved optimization formulation with randomness is employed for robust near-optimal parameters. Under the assumption that forward velocity of the robot is always positive, we apply the proposed IT2FPD controller to the snake robot model so that the robot can have locomotion along the desired trajectory against uncertainties. To validate the performance of the proposed robot model and control scheme, we conduct in-depth numerical experiments using 20-sim software. Experimental results demonstrate that the snake robot embedded with the IT2FPD controller achieves a straight-line locomotion with the serpenoid gait function despite infiltration of external disturbances and parameter changes.

Robust diagnosis of PEM electrolysers using LFT bond graph

A model based diagnosis for Proton Exchange Membrane (PEM) water electrolyser has been presented in this paper using Linear Fractional Transformation (LFT) bond graph technique. LFT helps in calculating the adaptive thresholds in order to make the diagnosis robust against parameters and measurement uncertainties, hence avoiding false alarms. A modular approach has been followed that allows the model to be adapted to different configurations of PEM electrolyser. The developed diagnosis has been first tested offline by injecting the faults into behavioural model of the PEM electrolyser and then implemented online for a single cell PEM electrolyser.

Priority flow divider valve and its dynamic analysis using various hydraulic drive systems: a bond graph approach

Abstract. The priority flow divider valve (PFDV) is used in power hydraulic system to split the supply flow in dual paths, i.e., primary path and secondary path. The flow ratio in each path is either predetermined or can be adjustable as per the loading conditions. The stated properties of the valve can be applied in a steering mechanism in automobile and a hydrostatic power transmission unit in a wind turbine. In a steering mechanism, it helps the system to perform two different functions against two different loads simultaneously, whereas, in a wind turbine, it can be used in hydrostatic power transmission unit to reduce the power fluctuation obtained from it. The hydrostatic power transmission system with PFDV (SMHPTSPFDV) used in a steering mechanism and the hydrostatic power transmission system with PFDV (WTHPTSPFDV) used in a wind turbine are modeled using the bond graph technique, and simulated in SYMBOLS Shakti software to analyze the steady and dynamic performance of the PFDV. The user-defined rectangular and sinusoidal variable pump speed has been used as inputs for system performance analysis. It is found that the PFDV may handle dual loads simultaneously, and it eliminates the use of multiple control valves to operate the same dual loads. Hence, it not only improves the system stability but also reduces the maintenance cost of the system. Moreover, the power and energy loss through the PFDV have been analyzed for both applications. It has been found that the power loss through the PFDV is higher when it is connected with SMHPTSPFDV. Also, the influences on the power and energy loss through PFDV are analyzed under various loading conditions.

Linear actuator–based knee exoskeleton for stand–sit–stand motions: a bond graph approach

People with knee disorders often find it difficult to perform common mobility tasks, such as stand–sit–stand motions. High knee torque is required to complete such transitions, as the chances of toppling increase during these motions. Most of the existing conventional approaches, such as wheelchairs and crutches, have failed to provide complete independence to the users. Conversely, contemporary systems like lower body exoskeletons which are bulky, complex, and expensive do not specifically target the knee joint instead of assisting other joints. Hence, there is a need to aid the knee joint using a robotic knee exoskeleton capable of accurately providing the desired knee torque. In the present work, to assist the user in performing the stand–sit–stand motions, an electromyography sensor-based four-bar knee exoskeleton actuated by a linear actuator is proposed. The modeling of the complete exoskeleton is developed using bond graph technique, as the components exist in different energy domains and it is possible to frame a dynamic bond graph model using only kinematic equations. The prototype is fabricated, and experiments are carried out on an artificial limb to prove the efficacy of the design of the current knee exoskeleton. The assistive torque developed by the actuator at the knee joint of the exoskeleton is found to be suitable to assist the wearer. As a result, little effort is required by the wearer for performing the stand–sit–stand motions. The rotation of the thigh link of the developed exoskeleton was found to be suitable for performing the stand–sit–stand activity.

Effect of pump leakage on slip and pressure loss in a hydraulic cylinder drive

Pump leakage plays a critical role in the safety as well as the functioning of hydraulic drives. Studying the effect of pump leakage on the dynamics of hydraulic drive can improve the drive safety by giving insight into dynamic symptoms of leakage fault and can improve the functioning range of drive by giving insight into the slip and pressure losses of the drive during steady and transient states. This article aims at dynamic characteristic analysis of pump leakage in a hydrostatic drive with linear actuator and lever mechanism. Such hydraulic drives are used in several earth moving machines e.g. crane, dumper truck, front loader etc. To carry out this analysis, the system model is developed using the Bond graph technique and validated using real measurements. Finally, the developed model is utilized to generate and analyse the system dynamics under different intensities of pump leakage. The steady state portion of the results indicate that the pump leakage results in significant slip or flow loss as compared to pressure loss. However, the transient portion of the result indicates that effect of pump leakage is almost same on both slip loss as well as pressure loss of the drive.

Dynamic modeling and analysis of a hydro-mechanical power transmission system

This work proposes a hydro-mechanical power transmission technology. It is a combined concept of mechanical and hydraulic power transmission. This scheme overcomes the individual issues of the both power transmission systems, and provides various combined advantages such as it not only attain higher output speed but also provides a suitable provision to store excess energy into it. A dynamic model of hydro-mechanical power transmission technology is developed using bond graph (BG) technique and simulated using SYMBOLS SHAKTI software. Simulation responses of the model indicate that the output speed of the hydro-motor is gained due positive gear ratio and hydraulic system added higher system controllability potential.

Application and implementation of the bond graph methodology on the structural damage detection and monitoring of aeroengines

Advancements in structural safety are of prominent importance in various industrial sectors. A significant body of research has been dedicated to proposing theoretical and empirical guidelines for detecting, localizing, and assessing the severity of damage to structures. This research proposes a novel theoretical approach that employs a bond graph methodology to perform structural health assessments of aeroengine structures. In this work, a reduced aeroengine model is proposed. Using the bond graph technique, the governing dynamic equations of motion can be determined. The results obtained from the analysis can then be used to perform a structural health assessment of the aeroengine. The outcomes allow for detection and localization of any damage to the structure, based on the regions identified. In the present study, damage indicator factors have also been determined for specified aeroengine regions, which can be used to localize damage and assess the severity of its propagation in an aeroengine. The proposed theoretical structural health monitoring methodology has notable advantages over other processes proposed in the literature. The present work allows for a reduction in the cost associated with damage detection, localization, and propagation. The proposed theory offers an accurate theoretical benchmark for comparison with experimental data when assessing structural integrity. Moreover, the proposed methodology can be used to develop and implement design modifications based on design objectives, ensuring continuous and safe operation of aeroengine structures.

Fault diagnosis and prognosis of steer-by-wire system based on finite state machine and extreme learning machine

In this paper, an integrated condition monitoring method combining model-based fault diagnosis and data-driven prognosis is proposed for steer-by-wire (SBW) system. First, the SBW system is modeled by bond graph (BG) technique and a two-degree-of-freedom (2-DOF) state-space model of the vehicle is built. Based on the 2-DOF model, the estimated self-aligning torque is used for the control of feedback motor. The fault detection is carried out by evaluating the analytical redundancy relations derived from the BG model. Since the fault isolation performance is essential to subsequent fault estimation process, a new fault isolation method based on finite state machine is developed to improve the isolation ability by combining the dependent and independent analytical redundancy relations, where the number of potential faults could be decreased. In order to refine the possible fault set to determine the true fault, a cuckoo search (CS)–particle filter is developed for fault estimation. Based on the estimated true fault, prognosis can be implemented which is important to achieve failure prevention and prolong system lifespan. To this end, an optimized extreme learning machine (OELM) is proposed where the input weights and hidden layer biases are optimized by CS. Based on data representing fault values obtained from the fault identification, the OELM model is trained for remaining useful life prediction of failing component. Finally, the proposed methodologies are validated by simulations.

Different Dynamic Formulations for a Mechanism using Bond Graph

For modeling dynamics of mechanisms, various classical formulations are available in the literature. The equations of dynamics given by various classical formulations can also be derived from the bond graph. The bond graph is a convenient graphical representation for modeling dynamics of physical systems in multi-energy domains.In this paper, various alternative causality assignment procedures in the bond graph are used to derive different classical formulations such as the Lagrange’s equations of the first kind (with multipliers), Lagrange’s formulation of the second kind, and Hamiltonian formulations. An example of the quick return mechanism has been modeled using the bond graph technique, and various alternative causality assignment procedures are applied to derive the various formulations. Simulation coding has been done using MATLAB and results have been analyzed and discussed. The purpose of this paper is to show how the various formulations can be obtained from bond graph using various alternative causality assignment procedures.

Comparative study of knee joint torque estimations for linear and rotary actuators using bond graph approach for stand–sit–stand motions

Stand–sit–stand (STS) motions are the most frequently performed activities of everyday life and require extensive movement of knee joint. People suffering from knee joint disorders face difficulties in performing this motion. The compact knee exoskeleton (KE) has proven to be a viable, less complex, and cheaper alternative to the available entire lower-, upper-, and full-body exoskeletons. With growing number of technical glitches and finite battery life problems, there exist risks of sudden failure of the actuator of KE that could be detrimental for the vulnerable users. To overcome this problem, there is a need to accommodate a backup actuator in KE which can continue providing assistance during movement if the primary actuator ceases to function. This article provides a performance comparison of a four-bar mechanism-driven KE that can accommodate both the linear and the rotary actuators. The modelling and simulation of the system are performed using the bond graph (BG) technique. The results successfully showed that both actuators offered desired ranges of motions needed for STS motion. Furthermore, the knee joint torques developed by the linear and rotary actuators were found to be 40 Nm and 57 Nm, respectively, which corresponds to 60% and 85% of the total torque required by the knee joint to perform STS motions, thereby reducing the user effort to 40% and 15%, respectively. Thus, both actuators are self-capable to provide necessary assistance at the knee joint even if the primary actuator ceases to work due to a sudden fault, the secondary actuator will provide the required rotation of the thigh link and will continue to deliver the assistive torque. The article also effectively shows the application of BG approach to model the multidisciplinary systems like KE as it conveniently models the system containing various elements in different energy domains.

A multi-product job shop scenario utilising Model Predictive Control

Multi-product manufacturing scenarios today have to face many challenges considering external factors such as availability of resources or attending product demands and internal factors such as adjustment of buffer levels or utilisation of workstations. In this paper, a multi-product job shop consisting of workstations coupled by an unidirectional material flow with different production routings is considered. The existing model based on the bond graph technique is adapted to an optimal control problem, allowing the applicability of the Model Predictive Control scheme. Concerning performance criteria, two different objective functions are defined: the first aims for predefined processing frequencies of the workstations and the second one takes into account product demands. Both approaches were examined in simulations showing that a steady state is achieved in terms of stable buffer levels and processing frequencies.

Inverse Kinematics of a Spatial Mechanism using Multibond Graph

Various methods are available to compute kinematics and dynamics in the case of spatial mechanisms. These methods are cumbersome and laborious for large and multibody spatial mechanisms. The bond graph technique is a powerful alternative tool for modeling. A four-link closed-chain 3R2S (3Revolute 2Spherical) spatial mechanism stands out among the other four-link closed-chain spatial mechanisms due to its ability to be used in a number of applications. The main aim of this paper is to compute the inverse kinematics of the mechanism using the bond graph structure of the system. In this paper, modeling of a four-link closed-chain 3R2S spatial mechanism has been conducted using a multibond graph approach. Inverse kinematics of the spatial mechanism, under various applications, has been directly obtained from the bond graph modeling. MATLAB coding for simulation has been done directly from the multibond graph without explicitly deriving system equations. The simulation results have been analyzed and discussed using various plots.

Modeling and Analyses the Equivalent-Schema Models for OSRR and COSRR Coupled to Planar Transmission Lines by Scattering Bond Graph

Following consumer demand, international competition has become increasingly high, suddenly industrialists are mobilizing to meet the requirements. Faced with this challenge, and in order to be able to respond to these prerequisites, manufacturers are looking for techniques that will allow them to gain productivity by increasing the rate of perfection before going to manufacturing. Modeling presents the most important phase in a construction chain since it allows not only analysis and understanding of the physical system but also to improve its behavior according to the desired objective from the design phase. The results presented in this article concern the modeling of the transmission lines of metamaterials loaded with OSRR Split-Ring Resonators and COSRR Complementary Open Split-Ring Resonators resonators, with the aim of improving analysis, synthesis and understanding of this system. By using the Scattering Bond Graph technique, which improves the adaptation of the impedance, and reduces the bandwidth. This technique allows us to deduce the scattering parameters (matrix [S]) of the OSRR / COSRR TL elements from the wave matrix [W], hence this matrix is determined through on the specific properties of the equivalent Bond Graph presentation based on the notion of causality.

Bond Graph Modelling and Simulation of Planar Quadruple Robot with Different Gaits

Legged robots have capability of traversing on any type of terrain with much ease and stability compared to wheeled robots. The legged robots do not have continuous contact with ground, and thus, it is easy to avoid obstacles. The objective of this paper is to model and simulate a walking mechanism for quadruple model that is stable and is able to implement different types of gaits. The stability control of legged robot is of utmost importance as compared to wheeled robot as contact from ground is discontinuous due to lifting and placing of leg. The positing of legs relative to body of robot considerably affects the stability, and also the sequence and timing in which legs are moved and placed play important role in energy efficiency. Here, model of quadruped robot with four legs has been developed using bond graph technique. Results from simulation are discussed. The comparison of different gaits is made for energy efficiency.

Analysis of Energy Harvesting in a New Prosthetic Foot Via Bond Graph Method

This paper proposes the application of the Energy Harvesting concept to quantify the energy potential of mechanical energy from the direct contact of a prothetic foot with the ground during walking. Dynamic system modeling was used via Bond Graph technique. As a result, the mathematical model can be considered stable due to the location of the poles and zeros. The values of the simulated results converge to the experimental results, demonstrating the consistency, stability and convergence of the model. Furthermore, the use of Bond Graph technique allowed to quantify the power in 75 W during walking.

Power-optimized motion planning of reconfigured redundant space robot

Main advantage of redundant space manipulator is that it can be configured differently by actuating various joints. Space manipulators are designed to be deployed in harsh surroundings, which in turn would increase the possibility of manipulator failure. Thus, the enhancement of the capabilities of the robots and the failures thereafter are a major concern. This article presents three aspects of hyper-redundant space robot. First, the control strategies based on minimum power criterion with all healthy joints are proposed. Second, hyper-redundancy is put upon to reconfigure the space robot with the failure of locked joints. Third, the optimization of workplace trajectory of the manipulator is obtained by genetic algorithm and a minimum power criterion has been adopted in all three cases. The bond-graph technique is employed for robot modeling with the use of SYMBOLS Shakti software, which generates system equations in C++ code. This code is subsequently converted into a MATLAB program. The result obtained through simulation shows that 37% of the total power consumption was reduced by the actuators through an optimization approach.

Bond graph observer for mode identification and discernibility study

This paper presents a new concept for calculating of the bond graph observer gains based on a graphical approach that investigates the Lyapunov Second Method in order to conclude about the observer stability and to search for the adequate gains that stabilize the observer. This new observer is used in the mode identification procedure. In fact, the observer’s residues allow the differentiation between the current mode and the other system modes. In order to guarantee the efficiency of the mode identification procedure, a new bond graph approach is proposed. It concerns the discernibility between the modes in bond graph language. First, it deals with the R-discernibility that introduces the definition of the discernibility through the structural parity residual then returns to a simple calculation of some matrices’ ranks in bond graph language. Second, another bond graph technique is applied to define the discernibility throughout the equivalency between the realizations.

Bond graph modeling of soft switching concept and its parameters optimization

ABSTRACTThe function of a soft switch is to provide a temporarily flow path of high pressure throttle fluid and store it temporally in a small chamber during valve transition, thus leading to passive vibration isolation. In this article, three different on/off controlled hydraulic systems without and with soft switch have been modeled using bond graph technique and simulated to analyze the performance of the soft switch. Some key parameters of the soft switch are identified and their values are optimized through multiple-run simulation. Thereafter, a relationship has been derived between the soft switch parameters and the overall energy loss of the system using regression analysis. It has been observed that the total energy loss in the system with soft switch is about one-third of that when the system is operated with relief valve only.