•The initial torque equation of the hydro-turbine is transformed to differential form.•A synergetic control method for excitation and governor systems is proposed.•The excitation control law output ...is introduced into the governor system.•The proposed controller reduces output oscillation and suppresses hydraulic coupling.
The existence of a shared pipeline in a multi-machine system can lead to hydraulic coupling effects between units. It increases the difficulty of controlling hydroelectric units and affects the stability of the power system. This paper refines the model of the hydroelectric generator unit and builds a nonlinear model of a hydro-generator unit with the single penstock multi-machine system. The synergetic control theory was introduced, and the governor and excitation system controllers were designed separately. A joint synergistic controller is obtained by analyzing the two systems' synergistic factors and controlled characteristics. This controller realizes the joint control of the excitation and governor system. The simulation selected a proportion-integral-derivative (PID) controller with optimized parameters, synergistic governor controller (SEC), and synergistic excitation controller (SGC) for comparison to verify the effectiveness of the proposed method. The results indicate that the proposed control method exhibits competent control effects in the single penstock multi-machine system. It can reduce the impact of hydraulic coupling, shorten the adjusting time, and ensure the fast and stable operation of the system. In addition, the values of system time parameters and synergetic control parameters are analyzed separately to provide a reference for achieving optimal control.
Vehicle active safety receives ever increasing attention in the attempt to achieve zero accidents on the road. In this paper, we investigate a control architecture that has the potential of improving ...yaw stability control by achieving faster convergence and reduced impact on the longitudinal dynamics. We consider a system where active front steering and differential braking are available and propose a model predictive control (MPC) strategy to coordinate the actuators. We formulate the vehicle dynamics with respect to the tire slip angles and use a piecewise affine (PWA) approximation of the tire force characteristics. The resulting PWA system is used as prediction model in a hybrid MPC strategy. After assessing the benefits of the proposed approach, we synthesize the controller by using a switched MPC strategy, where the tire conditions (linear/saturated) are assumed not to change during the prediction horizon. The assessment of the controller computational load and memory requirements indicates that it is capable of real-time execution in automotive-grade electronic control units. Experimental tests in different maneuvers executed on low-friction surfaces demonstrate the high performance of the controller.
The unmanned ground vehicle (UGV) travels in complex and uncertain terrain. Its vertical stability is a key factor affecting the working state and service life of high-sensitivity on-board sensors ...and mechanical structures. With the development of unmanned platform, a six-wheel independent drive UGV (6WID UGV) came into being. Its complex operating conditions and the unique configuration of active hydro-pneumatic suspension (AHPS) put forward higher requirements for vertical stability control. Based on the AHPS of 6WID UGV, a revised active disturbance rejection sliding mode controller (R-ADRSMC) is designed to improve the vertical stability of UGV. Firstly, the dynamic model of AHPS was established, and a test platform was built to verify the accuracy of the nonlinear characteristics of stiffness and damping. Secondly, an extended state observer (ESO) is used to estimate the disturbance caused by the model’s high nonlinearity and uncertainty. The known disturbance is fed back to ESO to form feedforward compensation, which improves the accuracy of disturbance estimation and compensation. Thirdly, the output of ESO is incorporated into the control law of the sliding mode controller (SMC), giving the control law real-time adaptive capability to the state of suspension system. Finally, the effectiveness of R-ADRSMC and its strong robustness to the uncertainty of road and load parameters are verified by simulation. The results show that compared with passive suspension (PS), active disturbance rejection control (ADRC), and SMC, the proposed R-ADRSMC can effectively improve the vertical stability of UGV under complex road conditions and has better control characteristics.
•A vertical stability control strategy (R-ADRSMC) for AHPS system is proposed.•The uncertain disturbances are estimated and feedforward compensated by ESO.•The dynamic model of AHPS system is validated by the experimental results.•The effectiveness and robustness of proposed strategy are verified by simulation.
For the next generation fusion devices, the presence of in-vessel coils is fundamental to deal with elongated plasmas and alternative configurations, highly performant, yet critically sensitive to ...the vertical unstable mode. A pair of equatorial in-vessel coils connected in anti-series is sufficient to deal with the vertical control problem. In case of independent equatorial coils, they can also be used to produce a fast radial control action able to preserve plasma facing components during fast plasma transients. The main criticality of independent in-vessel coils is related to the induced current during disruptive events, making the coils extremely vulnerable due to overcurrents and mechanical stress. In this paper, we present the solution proposed for the conceptual design of the in-vessel equatorial coils for the Divertor Tokamak Test fusion device. This solution is able to guarantee radial and vertical control performance and robustness in case of disruption. Simulations are provided to show the efficiency of the design in case of disruptions and the effectiveness of the closed-loop control actions.
The security and stability control system is the guarantee of the security and stability operation of the power grid. With the increasing scale of distributed new energy access to the power grid, the ...security and stability control strategy of the power grid is becoming more complex, and it is becoming increasingly important to correctly analyze and implement the security and stability control strategy. In order to ensure the correctness of the security and stability control strategy implemented by the security and stability control device, it is necessary to analyze the security and stability control strategy in detail. Therefore, this article proposes an intelligent analysis method of the security and stability control strategy based on the knowledge graph. First, this article introduces the ontology design method of the security and stability control strategy based on the knowledge graph, combines the characteristics and applications of the knowledge graph, analyzes the relationship between the elements of the strategy, and designs a clear-structured knowledge network. Second, this article analyzes the automatic construction technology of the graph, constructs the six-element ontology model of the security and stability control strategy, and realizes the human–computer interaction functions such as auxiliary decision making, strategy reasoning, and intelligent search based on the knowledge graph. Using artificial intelligence technology, this article takes the security and stability control strategy of a certain area’s security and stability control system as an example to model and manage. The results show that it can assist the tester to quickly retrieve the strategy, effectively improve the detection efficiency of the security and stability control strategy, avoid the omission and ambiguity caused by the manual understanding of the strategy, and ensure the accuracy and comprehensiveness of the security and stability control strategy detection.
Sideslip angle plays an important role in vehicle stability control. However, it is difficult to measure directly unless some complex and expensive devices are employed. Thus, sideslip angle ...estimated by vehicle states such as lateral acceleration, yaw rate and so on is required in real-time vehicle stability control. A new variable structure extended Kalman filter integrated with the sideslip angle rate feedback algorithm and damping item is proposed in this paper. The main idea of the sideslip angle rate feedback algorithm is to compensate the model error caused by road friction estimation inaccuracy while that of the damping item is to suppress the error accumulation. The estimated results are compared with the real values obtained by the differential global position system on a low friction road and it shows that the proposed methodology can provide accurate sideslip angle to some extent for vehicle stability control.
•Evolutionary game model was established, analyzed and simulated.•The SACMS, LRDCMS, and coal enterprises strategy selections fluctuates repeatedly.•Effective measures on controlling the game ...stability are proposed.
In the process of coal mining safety inspection in China, the different interests and influences of stakeholders and their complicated dynamic interactions make the coal mining safety laws and regulations less effective. Moreover, the existing literature on China’s coal mining safety inspection is short of research on revealling the dynamic interactions that can occur under the bounded rationality and also on proposals for effective interactions that will lead to improved safety outcomes. Therefore, this paper explores the use of evolutionary game theory to describe the interactions between the stakeholders in China’s coal mining safety inspection system, which includes the State Administration of Coal Mine Safety (SACMS), the Local Regulation Departments of Coal Mine Safety (LRDCMS), and coal enterprises. Moreover, the paper also explores dynamic simulations of the evolutionary game model to analyze the stability of stakeholder interactions and to identify equilibrium solutions. The simulation results show that the strategy selections of the three stakeholders fluctuate repeatedly, which indicates that the evolutionary stable strategy does not exist in the current interactions between the stakeholders. Therefore, the dynamic penalty control scenario and an optimized dynamic penalty-incentive control scenario were proposed to control the fluctuations and then simulated again. And the simulation results indicated that the dynamic penalty control scenario can effectively restrain the fluctuations and make stakeholder interactions more stable. Furthermore, the optimized dynamic penalty-incentive control scenario can not only restrain the fluctuations effectively but also present an ideal evolutionary stable strategy in which coal enterprises could nearly choose safety production as their optimal strategy.
•Studies on EU-DEMO 3D coils requirements and conceptual design for error field correction and plasma control.•Assessment if one set of coils can fulfil a list of functional requirements: EFC, ...manipulation of the locked NTMs phase, and ELM suppression or mitigation.•Calculations are performed to verify that the 3D fields applied do not generate 3D power exhaust effects that jeopardize the protection of the machine divertor/wall.•Considerations on the coil technology and configurations shows that no showstopper have been found in this preliminary phase.
This work presents the initial studies on the requirements for the design of 3D coils on EU-DEMO. The use of 3D coils in present machines includes two main purposes: the first one is the Error Field Correction (EFC). The EFC aims at minimizing the intrinsic non-axisymmetric fields in the machine. Fulfilling the requirements is evaluated with the minimization of residual error fields, both in vacuum and with plasma response. The second purpose relates to the application of 3D fields to control the plasma. The first of these control functions includes the manipulation of the locked neoclassical tearing modes (NTMs) phase, and their positioning in front of the electron cyclotron antennae, for optimum stabilization. A second function is the application of 3D perturbation of the plasma edge to suppress ELMs. As the fastest required time constant of the applied 3D fields is comparable or longer with respect to that of the vacuum vessel, ex-vessel coils can be considered. Another constraint considered is that the 3D fields applied do not generate 3D power exhaust effects, such as divertor lobes, that jeopardize the protection of the machine divertor/wall. This constriant is met in the finding of this work, in the case considered of the ELMs suppression. The aim of this study is to assess if one set of coils could be designed that fulfills all these purposes/functions. The results show that, by using ITER tolerances for the TF, CS and PF coils, all these functions on EFC (using the overlap criterion assumption, which includes the plasma response), NTM phase control and ELMs suppression can be met with the proposed design of one row of ex vessel coils. An additional activity has started to study if the non-resonant perturbations generated by this set of coils could lead to detrimental effects via neoclassical toroidal viscosity (NTV) torque. Preliminary considerations on the coil technology, are also presented, with no showstopper found in this preliminary phase.
The stability control of passive walking has been a major challenge in the field of passive robots because of its significant nonlinear characteristics. Using the adaptive sliding mode control based ...on local approximation of Radial Basis Function Neural Network (RBFNN), the walking stability of the simplest point foot model of biped passive robot is investigated in this paper. Simulation results show that the passive robot with this control method could achieve stable periodic gait with fewer steps than the robot without the control. In addition, given different control target state functions according to the characteristics of passive walking gait, passive robot can stabilize to corresponding periodic walking state with small control errors under the adaptive sliding mode control based on RBFNN. Finally, the influences of the gain coefficients of weight updating formula of RBFNN and the robustness coefficients of adaptive sliding mode controller on the control error results are discussed. It is found that the error decreases when the parameters increase within a certain limit, and the control effect becomes less obvious when the parameter exceeds the limit range.
•The RBF Neural Network is applied to the adaptive sliding mode controller to obtain accurate control effect.•The control method in paper can make passive robot achieve stable walking faster than the robot without control.•Passive robot could walk stably under the control with different control objective state functions.•The control method has higher control precision by adjusting the controller parameters.
