Multi-mode switching in flight control

This paper presents a multi-mode controller approach for a constrained linear system with bounded disturbances based on the model predictive control (MPC) framework. Compared with single MPC controller implementations, the proposed approach has the flexibility of having a large domain of attraction, good asymptotic behavior and reasonably low on-line computation. The closed-loop control law of the multi-mode controller is available in closed-form. In this case, the proposed controller has fewer partitions of the domain of attraction compared to single MPC controller having similar domain of attraction. The performances of the approach are presented via an example

We describe the implementation of the multiple model-based failure detection and identification (FDI) and adaptive reconfigurable control (ARC) algorithms of Boskovic and Mehra (see Proceeding of the 1998 Conference on Decision and Control, Tampa, FL, 1998) anf of Boskovic, Li, Rago and Mehra (see Technical report, Scientific Systems Co., Inc., 1999) in the nonlinear 6 DOF TAFA simulation. Due to the nonlinear nature of the simulation, the implementation and tuning of the algorithms is substantially more complicated than their counterparts in linear simulations. However, the well tuned FDI-ARC achieved excellent performance despite severe flight-critical variations in the aircraft dynamics.

This paper investigates the design and verification of a hybrid model predictive controller of a damping multi-mode switching damper for application in vehicle suspensions. Since the damping mode switches induce different modes of operation, the vehicle suspension system including this damper poses challenging hybrid control problem. To solve this problem, a novel approach to the modelling and controller design problem is proposed based on hybrid modelling and model predictive control techniques. The vehicle suspension system with the damping multi-mode switching damper is formulated as a mixed logical dynamical model comprising continuous and discrete system inputs. Based on this model, a constrained optimal control problem is solved to manage the switching sequences of the damping mode with respect to the suspension performance requirements. Numerical simulation results demonstrate the effectiveness of the proposed control methodology finally.

A power-split hybrid electric vehicle (HEV) combines the advantages of both series and parallel hybrid vehicle architectures by utilizing a planetary gear set to split and combine the power produced by electric machines and a combustion engine. Because of the different modes of operation, devising a near optimal energy management strategy is quite challenging and essential for these vehicles. To improve the fuel economy of a power-split HEV, we first formulate the energy management problem as a nonlinear and constrained optimal control problem. Then two different cost functions are defined and model predictive control (MPC) strategies are utilized to obtain the power split between the combustion engine and electrical machines and the system operating points at each sample time. Simulation results on a closed-loop high-fidelity model of a power-split HEV over multiple standard drive cycles and with different controllers are presented. The results of a nonlinear MPC strategy show a noticeable improvement in fuel economy with respect to those of an available controller in the commercial Powertrain System Analysis Toolkit (PSAT) software and the other proposed methodology by the authors based on a linear time-varying MPC.

Two versions of a distributed-memory model, one for associative information and one for serial-order information, leave open the question of whether there are two different modes of operation or only one. An analysis of these two versions showed that differential predictions emerge when one considers the role of item information. To test these predictions, a standard item-recognition task (Sternberg, 1966) was embedded in a paired-associate probe-recognition task, a serial-order probe-recognition task, or both. The item-recognition serial-position curves were quite different in the paired-associate and the serial-order conditions, and followed the paired-associate condition when the two were combined. In general, the results were consistent with the predictions of the distributed-memory models, and supported the idea of different modes of operation rather than a single common mode of operation.

A novel energy management optimization strategy for integrated photovoltaic-storage LVDC systems using dynamic multi-mode switching under energy market-oriented conditions

In the paper we first present several failure models, and derive the model predictive control (MPC) algorithm for the no-failure case when the objective is to track the outputs of a reference model. Following that, the multiple model switching and tuning methodology, as applied in the context of failure detection and identification (FDI) and adaptive reconfigurable control, is presented and described in detail, and its stability and convergence properties are discussed. Multiple model predictive control (MMPC) approach is presented and the MMPC algorithm is derived for the case of lock-in-place control effector failures. Combining the online FDI system with the MPC approach results in an efficient MMPC algorithm that is well suited for different types of failures.

The brain circuitry of attention

The problem of the development of modern bearings (magnetic, gas, etc.) for high-speed machines with a wide range of capacities (from tens of kilowatts to megawatts) and rotational speeds (from 6000 to 60000 rpm) used in oil and gas production, robotics, space technology, and mini gas-turbine power plants is considered. The distribution of forces applied to the rotor shaft in different modes of operation is investigated including the case of shaft eccentricity. In operation, the eccentricity should not exceed 5%. A computer system is designed on the basis of the numerical method for field (2D) computation in the active part of the machine. The distribution of forces is analyzed taking into account the saturation of the magnetic circuit of the machine and the harmonic content of the mutual magnetic flux (flux in the gap). When calculating these forces in the no-load mode of operation, it was assumed that, in machines with permanent magnets, the mutual magnetic flux on the rotor is about 10–15% higher than under the rated load because of the demagnetization effect of the armature reaction. The mutual magnetic flux was specified depending on the type of rotor magnets. The computer system takes into account the relative position of the rotor poles relative to the stator field reaction under load (load angle Θ). It is also taken into account that, during use, the resulting mutual magnetic flux is distorted (compared to the no-load mode). As a result, a number of additional high harmonics appear in the gap, which affect the forces applied to the rotor shaft. Load angle Θ is calculated using graphical options of the simulation package by the iteration method. An algorithm for the implementation of this method is described. The distribution of the radial forces along the rotor shaft surface (differential parameter) and the total radial attraction force applied to the rotor shaft (integral parameter) are calculated for different values of eccentricity and different modes of operation of high-speed machines.

Molecular characterization of the microbial community structure in two activated sludge systems for the advanced treatment of domestic effluents

The paper is focused on simulating the discharge of Li-Ion batteries using series and parallel cells in different modes of operation. The simulations are realized using Matlab/Simulink. Two cases are analyzed for the system under test: constant discharge current and a variable discharge current. In these cases the batteries were considered 100% or partially charged. For a series cell we used four batteries and for the parallel connection we used three series cells. The simulated waveforms for the state of charge (SoC) and the output voltage of batteries are presented for the analyzed cases.

With the growing number of physically disabled person in the present age, the usage of wheelchair has become unprecedented. Electric autonomous smart wheelchairs have emerged as the go to caring module for the disabled people. The proposed electric health monitoring smart wheelchair system is intended to be an all-in-one electric wheelchair that surpasses its previous predecessors. It allows the user to independently move around both indoor and outdoor using 3 different mode of operation – gesture control for controlling via neck movement, Joystick control & voice command module. It is incorporated with ultrasonic sonar edge detection module & obstacles detection both front and back to ensure safety of the patient. A variety of sensors such as heart rate sensor, PIR sensor, load cell, temperature & humidity detection are attached to keep monitoring the patient while he/she is sitting on the wheelchair. In the event of any accident or anomaly in the health monitoring data, the system will notify the relative and affiliated medical institution via SMS combined with GPS location. The proposed wheelchair system also incorporates retractable solar panel to charge the battery while operating outdoors. The proposed prototype model has been tested in a local area and the practical simulation data gained is promising. As a whole, the proposed prototype has a great deal to offer to the disabled population.

The stringent safety requirements for civil aircraft flight control have consistently favoured the application of Proportional Integral Derivative (PID) in conventional flight control design. However, PID gain adjustment becomes burdensome when designing multimode flight control laws within the full envelope. For advanced civil aircraft, the complexity of mode management and gain adjustment is likely to escalate further. The Incremental Nonlinear Dynamic Inverse (INDI) holds promise as an effective solution. The scientific validity of INDI has been demonstrated through cases such as F35-B. However, there remains significant challenges in applying INDI to the flight control laws design of civil aircraft. One key challenge is the design of a unified INDI control scheme that can accommodate Level 1 flight quality commands. Another challenge is to demonstrate that INDI can effectively simplify gain tuning and mode management while achieving the desired control effect. This paper addresses these issues by proposing a model-based INDI control scheme and corresponding evaluation scheme, demonstrating satisfactory adaptability to the stringent safety requirements and the simplification advantages. The proposed solution herein is a meaningful endeavour to apply INDI to civil aircraft flight control law design, which contributes to leverage the advantages of advanced civil aircraft in various scenarios.

The YC-14 tactical transport aircraft uses three channels of digital flight control electronics (FCE) to provide fail-operational, fail-safe augmentation of the basic flight control characteristics. This paper discusses the system-level testing performed to verify the software prior to first flight and then prior to flights using modified versions of the software. Testing is performed in two phases: the FCE are connected to a simulation of the aircraft systems with no aircraft dynamics (open loop); and the FCE are connected to a simulation of the aircraft systems and the aircraft dynamics with simulated sensor inputs (closed loop). A semiautomatic testing facility used for data management and control of the tests is described.

The existence of operational dead zone during mode switching in noninverting buck-boost converter results in oscillation of the output voltage and instability of the system during high power operation. The mechanism and effect of the operational dead zone are analyzed, the conditions that need to be met when eliminating the operational dead zone are researched, and a multimode smooth switching control strategy which can completely eliminate the operational dead zone is proposed. The converter works with three operating modes, the method of theoretical analysis combined with experimental correction is used to set the mode switching parameters, to ensure that the actual voltage gains of the converter on both sides of the mode switching points are equal. A single-degree-of-freedom buck-boost mode is designed to replace the pass-through mode to maintain the converter's stable output. And the converter's operating power level and overall power transmission efficiency can be improved, when the control parameters are designed to reduce the interval length of the boost mode and the single-degree-of-freedom buck-boost mode. Finally, a 700-W experimental prototype is built to verify the effectiveness of the proposed solution.