Control of a mobile robotic manipulator: a combined design approach

"This paper focuses on the problem of reducing via control actions the interaction between the mobile platform and the arm in a mobile robot equipped with a redundant planar manipulator. It is solved maintaining the mobile base as immobile as possible once it has been moved to a desired position, which serves to a double purpose. On the one hand, it helps keeping fixed the workspace of the manipulator, as predefined in the world coordinates, in order for the end-effector being able to reach the points where it has to perform its tasks. On the other hand, as this reduces the disturbances that the otherwise moving base would introduce on the arm movement, this serves to improve the precision in the execution of whatever task the end-effector has to perform. The problem is solved via a combination of operational space control to solve the arm tip trajectory tracking problem and energy-shaping and damping assignment to restrict the movement of the mobile base. The latter is achieved using a backstepping technique in the Bond Graph domain which emulates dissipation and stiffness at the base wheels coordinates through the control of the DC motors actuating them. Simulation results show the good performance of the control system."

Energy- and flatness-based control of DC-DC converters with nonlinear load

"This paper presents a passivity-based controller design (PBC) aimed at stabilizing DC-DC power electronic converters with nonlinear dissipative loads. The converters considered in this work are the buck, the boost and the buck-boost. First, Bond Graph technique is used to obtain the flat output of each converter model. The controller is designed within the port-Hamiltonian (pH) framework, ensuring stability and other desired closed-loop properties. To this aim a desired closedloop dynamics in pH form with a quadratic storage function and a flat-output-inspired change of variables are proposed, which are common to the three converters. The controllers that render the closed-loop dynamics in the desired pH form are obtained via model matching. This design has two major advantages. The first is that the so-called matching equation can be solved by construction; thus, the cumbersome task of solving partial differential equations is avoided. The second advantage is that in all the converters treated the closed-loop dynamics is linear; thus, the performance of the control system can be easily determined via the tuning of the eigenvalues of the closed-loop evolution matrix. The performance is assessed through digital simulation."

"Robustifying passive closed-loop Port-Hamiltonian systems using Observer Based Control"

"This paper contributes a passivity-based approach to obtain a control law that robustifies Port-Hamiltonian (pH) control systems under external and state-dependent disturbances using disturbance observers (DO). A twostage design procedure is used to define the Disturbance Observed Based Control (DOBC) scheme. In the first stage a passivity based control law, called Interconnection and Damping assignment (IDA-PBC) is designed in the Bond Graph (BG) domain via BG prototyping, using an undisturbed model of the physical system. This stage is not the main issue of this paper and therefore the IDA-PBC law will be assumed to be known. The second stage, the main result of this paper, consists in the design of the DO and its integration with the IDA-PBC control law. The DO is derived in the BG domain via the integration of the residual signal computed from a Diagnostic Bond Graph (DBG). The methodology is developed through examples in the BG domain and formalized and extended in the pH framework."

"Study of supply chain vulnerabilities based on cognitive engineering and ARIMA formal models"

"This research concerns the formulation of models and methods for supply chains risk analysis. An ontological approach using the KOD method (Knowledge Oriented Design) has been implemented to clearly identify relationships between the concepts of supply chain, risk, vulnerability and disturbances (critical scenarios). As a result, conceptual models of supply chains facing risk situations and critical scenarios are proposed. From the resulting conceptual models and mathematical models proposed in the literature, a multi-stage supply chain model using ARIMA models incorporating the randomness of the demand has been elaborated. In order to adapt this model to scenario criticality, constraints on orders and inventories have been taken into account. Under critical disturbances on information flows (demand) and physical flows (quality of the product supplied), constraints can be reached and supply chain behaviours can evolve toward critical dynamics or even become unstable. Supply chain vulnerabilities has been assessed and discussed."

Bond graph approach for disturbance rejection with Derivative State Feedback

"This paper presents the application to a real Torsion-Bar system of Disturbance Rejection by Derivative State Feedback using an Unknown Input Observer. Finite and infinite structures of the model are analysed with a structural approach directly on the bond graph model and thus properties of the controlled system as well as the observer are structurally highlighted. The effectiveness of the proposed method is assessed with actual tests on the Torsion-Bar system."

"Thermo hydraulic pseudo bond graph based modeling of a centrifugal pumppipe system with experimental analysis"

"The emergence of electrical energy is closely related to the use of power. However, the temperature of electronics could be compared to those encountered by a shuttle nose when entering the atmosphere and requires a thermal management. The technology investigated in this paper is original because able to evacuate important heat flux. The proposed system is named Biphasic Fluid Loop Mechanically Pumped (BFLMP) with a transport capacity of the thermal power up to 10 MW.m, exceeding in this way the performance of all known technologies. This paper begins with a description of the test rig of the BFLMP and its instrumentation. The second part of the paper is a detailed study of the thermo hydraulic behavior of the pump-pipe system. The proposed model is based on the bond graph theory because of its energetic approach and the multi-physics character of the studied system. A validation test is launched using water with regulation temperature at the pressurizer set at 60°C, the temperature of the secondary circuit is regulated at 37°C, a power crenel of 400 W has been applied on the evaporator. Results are discussed in a last part; the model shows up good agreement with the experimental results. The volumetric pump studied in this work is original because it was specially designed and manufactured to equip the BFLMP developed in collaboration with the research laboratory CRIStAL. This pump has been patented. Also, this centrifugal machine has been tested and has been characterized. Its performance curves are obtained and used in the model proposed in this paper. In addition, the proposed algorithm models the pump using a resistive bond graph element R."

"Bond graph approach for input-output decoupling of linear MIMO systems with Derivative State Feedback"

"This paper presents a new solution for the well-known input-output decoupling problem of linear multivariable systems with a derivative state feedback control law. A simple solution to the pole placement problem is highlighted in the monovariable and multivariable cases with application to a mechanical system. Analysis up to control design are achieved structurally in the bond graph domain for the case study."

"Realising optimum design of a hybrid renewable energy system using multiobjective evolutionary algorithm"

"This paper proposes a strategy to find the combined design of hybrid PV/wind electric system and the policy of financial support of state. Different from the most existing proposals, this study formalizes the problem as a multi-objective optimization considering the benefits of both user and supplier. Multi-objective evolution algorithm based on decomposition (MOEA/D) is adopted to solve the formulated problem. The proposed strategy is applied in the case of a company located in the southeast of France. The results validate the effectiveness of the proposal."

New results for global stability of neutral-type delayed neural networks

"This paper deals with the stability analysis of the class of neutral-type neural networks with constant time delay. By using a suitable Lyapunov functional, some delay independent sufficient conditions are derived, which ensure the global asymptotic stability of the equilibrium point for this this class of neutral-type neural networks with time delays with respect to the Lipschitz activation functions. The presented stability results rely on checking some certain properties of matrices. Therefore, it is easy to verify the validation of the constraint conditions on the network parameters of neural system by simply using some basic information of the matrix theory."

Design and verification of discrete event controllers for Smart Factory

"This paper presents a study on the development of smart factory in the context of the manufacturing industry. We show that such systems must be agile, i.e. able to adapt quickly to changing contexts such as a particular production or material faults. In this study we model the control system of these systems by a layered and generic approach. We distinguish several classes of models to manage different categories of flexibility. The main objective of the study is to provide a rigorous and systematic method for modeling and verifying systematically, rigorously and effectively this type of system."