A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and ...
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A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and accurate tracking of the aerodynamic angle commands with the finite time convergence. The proposed control strategy is developed on the basis of integral sliding mode philosophy, which combines conventional sliding mode control and a linear quadratic regulator over a finite time interval with a free-final-state and allows the finite-time establishment of a high-order sliding mode. Firstly, a second-order sliding mode attitude controller is designed in the proposed high-order siding mode control framework. Then, to address the control chattering problem, a virtual control is introduced in the control design and hence a third-order sliding mode attitude controller is developed, leading to the chattering reduction as well as the control accuracy improvement. Finally, simulation examples are given to illustrate the effectiveness of the theoretical results.
The optimal path planning for fixed-wing unmanned aerial vehicles(UAVs) in multi-target surveillance tasks(MTST) in the presence of wind is *** take into account the minimal turning radius of UAVs,the Dubins model is ...
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The optimal path planning for fixed-wing unmanned aerial vehicles(UAVs) in multi-target surveillance tasks(MTST) in the presence of wind is *** take into account the minimal turning radius of UAVs,the Dubins model is used to approximate the dynamics of *** on the assumption,the path planning problem of UAVs in MTST can be formulated as a Dubins traveling salesman problem(DTSP).By considering its prohibitively high computational cost,the Dubins paths under terminal heading relaxation are introduced,which leads to significant reduction of the optimization scale and difficulty of the whole ***,in view of the impact of wind on UAVs' paths,the notion of virtual target is *** application of the idea successfully converts the Dubins path planning problem from an initial configuration to a target in wind into a problem of finding the minimal root of a transcendental ***,the Dubins tour is derived by using differential evolution(DE) algorithm which employs random-key encoding technique to optimize the visiting sequence of ***,the effectiveness and efficiency of the proposed algorithm are demonstrated through computational *** results exhibit that the proposed algorithm can produce high quality solutions to the problem.
Hazard and operability (HAZOP) methodology is an important Process Hazard Analysis (PHA) technique for ensuring safety production in chemical industry. Due to the lacks of accuracy and reliability in manual HAZOP anal...
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ISBN:
(纸本)9781509029280
Hazard and operability (HAZOP) methodology is an important Process Hazard Analysis (PHA) technique for ensuring safety production in chemical industry. Due to the lacks of accuracy and reliability in manual HAZOP analysis, the quantitative HAZOP analysis has gained more and more attention. In this work, a process simulation-based HAZOP analysis method and its flow chart are proposed. And the proposed method is applied to a steam generation subsystem in an ethylene pyrolysis unit on a dynamic process simulation platform. All deviation parameters of system can be calculated and described quantitatively. The case study shows the proposed method is useful for the effective risk prevention and control measures in a chemical process.
This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system(RCS). Firstly, a novel finite-time attitude controller is p...
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This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system(RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency(PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS *** are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.
This paper aims to investigate an extended state observer (ESO) based control approach for the ground-coupled heat pump system (GCHP). As GCHP system has strong disturbances, a feasible approach of disturbance rejecti...
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Hydro-viscous speed clutch(HVC) is a central control element of the driver system. Because of nonlinearities and hysteresis of the clutch, the setting of control parameters has a significant impact on the performance ...
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Hydro-viscous speed clutch(HVC) is a central control element of the driver system. Because of nonlinearities and hysteresis of the clutch, the setting of control parameters has a significant impact on the performance of the speed control system. This paper studies the HVC of a vehicle temperature control system, and analyzes the parameters tuning method of a PID controller for the closed-loop control system. By employing a two-storey optimized control framework, the resulting model from identification can be used to complete the control parameters auto-tuning. Simulation and experimental results have showed that this auto-tuning method can obtain a group of parameters in terms of a desired performance index, which guarantees the balance of dynamic characteristics, stability and anti-jamming in closed-loop system.
In the multi-platform air defense combat, platforms cooperate to achieve best effect. In the traditional air defense cooperation, assigning interception units has been paid more attention. Based on the existing task a...
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ISBN:
(纸本)9781467374439
In the multi-platform air defense combat, platforms cooperate to achieve best effect. In the traditional air defense cooperation, assigning interception units has been paid more attention. Based on the existing task allocation model, we added the cooperative guidance and time window constraints to accord with the modern battle mode. An allocation method based on decentralized auctions is also proposed. Each platform employs the heuristic method to choose proper target and confirm the execution time, then resolve the conflict by consensus rules. This method is robust for communication network, besides it can avoid the single point of failure. Simulation results show this algorithm is significantly effective and satisfies the demand of real time.
This paper proposes adaptive fuzzy PD+ based controller for the attitude maneuver of rigid spacecraft. Based on the error of the system, the adaptive fuzzy PD+ based controller applies adaptive fuzzy algorithm to modi...
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This paper describes a novel amphibious robot, which adopts a dual-swing-legs propulsion mechanism, proposing a new locomotion mode. The robot is called FroBot, since its structure and locomotion are similar to frogs....
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This paper describes a novel amphibious robot, which adopts a dual-swing-legs propulsion mechanism, proposing a new locomotion mode. The robot is called FroBot, since its structure and locomotion are similar to frogs. Our inspiration comes from the frog scooter and breaststroke. Based on its swing leg mechanism, an unusual universal wheel structure is used to generate propulsion on land, while a pair of flexible caudal fins functions like the foot flippers of a frog to generate similar propulsion underwater. On the basis of the prototype design and the dynamic model of the robot, some locomotion control simulations and experiments were conducted for the purpose of adjusting the parameters that affect the propulsion of the robot. Finally, a series of underwater experiments were performed to verify the design feasibility of FroBot and the rationality of the control algorithm.
In this work,a finite-horizon optimal control problem for first-order plus time delay(FOPTD) processes is *** show that if the control horizon is greater than three and the prediction horizon is great than the control...
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In this work,a finite-horizon optimal control problem for first-order plus time delay(FOPTD) processes is *** show that if the control horizon is greater than three and the prediction horizon is great than the control horizon plus the time delay in discrete time,the optimal controller is not affected by either of the two ***,under these conditions,the controller parameters are explicitly calculated,the closed-loop system is shown to be stable,and the controller is *** problem considered is related to the results on linear quadratic regulation of linear systems with time delays;however,the detailed parameterization of the state-space model introduced by the FOPTD process provides an additional opportunity to investigate the exact controller structure and properties(e.g.,the locations of the closed-loop poles),which are also the major difficulties encountered and overcome in this *** problem is motivated from phenomena experienced in designing industrial model predictive control(MPC) tuning algorithms,and extensive numerical examples indicate that the proposed results speed up the MPC autotuning algorithms by 70%.
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