Control Laws For Vehicles Research Articles

Robust adaptive control for a class of autonomous vehicle platoons

SummaryThis article studies robust adaptive control for a class of autonomous vehicle platoons. In particular, two innovative adaptive control laws are proposed to address both position and velocity tracking for a vehicle platoon. In addition, it is shown that robust asymptotic string stability can be delivered by the underlying adaptive control laws for the vehicle platoon, in the sense that these adaptive control laws are capable of mitigating parameter uncertainties involved in the nonlinear vehicular dynamics and achieving truly cooperative adaptive cruise control while ensuring the required safety spacing between each neighboring vehicle pair asymptotically. It is also shown that the control performance of the vehicle platoon can be further improved if the operating equilibrium points of all vehicles can be adaptively estimated, leading to two linear time‐invariant control laws for individual vehicles under both position and velocity controls and for the vehicle platoon. Simulation studies illustrate the effectiveness of the proposed control method, validating the results obtained for the class of vehicle platoons.

The method of efficient individual control of electric traction motors of an electric portal axle during cornering

BACKGROUND: In recent years, the global automotive industry has shown increased interest in electric traction drive for road vehicles, including electric cars, electric buses and electric trucks, where various drive layouts are used. One of the most widespread drive layouts is an individual electric traction drive, which is often used in modern electric buses. The individual electric traction drive has such advantages as reliability in sustaining traction or braking forces in case of failure of one of the engines, compact placement of engines, low floor level along the entire length of the cabin and adaptation of the electric traction drive to road conditions. The last point of the mentioned advantages requires the development of an advanced control system. AIMS: Development of the yaw recognition algorithm and formation of the algorithm for designing a torque redistribution regulator. METHODS: Modeling of the operation of the yaw recognition algorithm is carried out during simulation tests in the MATLAB/Simulink software package. The main dependencies are derived, followed by obtaining a phase variable, for the correct operation of the optimal controller. RESULTS: The yaw recognition algorithm, which forms the torque redistribution between the driving wheels, is developed, an algorithm for designing an optimal regulator was developed, such concepts as theoretical and actual motion parameters are introduced. Simulation modeling of the spatial movement of an electric bus is carried out in the MATLAB/Simulink software package, showing the operability and efficiency of the developed system. The scientific novelty is the formation of the optimal regulator, making torque redistribution possible. CONCLUSIONS: The practical value of the development and research lies in the possibility of applying the algorithm and the control law for vehicles equipped with the individual electric traction drive.

線形二輪モデルを評価ツールとしたモデルマッチングと最適オブザーバの組合せによるロバスト操舵制御則の評価

Recently, in regards to vehicle steering control system based on steer by wire (SBW), the relationship between the vehicle response and steering input could change flexibly. There are some previous studies (e.g. H∞, LQG, Model Matching etc. ) to similar researches, but these researches are mutually exclusive for the desired response and robustness. We report the evaluation results of the robust steering control law by combination of model matching and optimal observer, which can realize compatible of vehicle desired response and robust characteristics to steer input disturbance simultaneously. Generally, this offered system can accommodate to develop the SBW system which realize compatible of vehicle desired response and robust characteristics to steer input disturbance simultaneously. Especially, the function to eliminate the input disturbance allows the efficient design to develop the vehicle control law realize compatible of the maneuverability and dynamic stability involving the static stability characteristics. The control plant, which abstracts the actual vehicle characteristics by linear bicycle model using the linear cornering stiffness, is positioned as the evaluation tool to verify the desired response and the robustness of offered control law. Although this linear bicycle model plant is positioned for the evaluation tool, in accordance with this research developing, we would verify the effect of this control law to the actual vehicle characteristics.

Evolution of attitude control law of an Indian re-entry launch vehicle

Reusable launch vehicle (RLV) is a goal pursued by different aerospace agencies, world-wide. Indian space research organization is also one among them. This paper covers the challenges faced and the solutions developed for control law design of a typical re-entry vehicle. The first stage of the test vehicle, used for technology demonstration mission, is a conventional solid rocket motor. The second stage of the test vehicle is a winged body vehicle termed as technology demonstrator vehicle (TDV). This TDV forms the orbiter stage of a conceptual two-stage-to-orbit vehicle. While developing control law for TDV, the experience gained in developing control law for expendable launch vehicles is fully utilized. Due to the presence of winged-second-stage, the solution for attitude control problem naturally inherits the procedure and technology used for designing control law of an aircraft. There are significant differences a re-entry vehicle has in comparison to both aircraft and launch vehicles. Due to these differences, the final control law depends on both aircraft and launch vehicle control law design methodologies. In this paper the authors share the insights gained in control law design of a RLV. The paper gives the reasons for the selection of a combination of co-ordinate systems, for the development of linear plant model of RLV. It emphasizes the difference in the plant modelling with respect to aircraft dynamics in accounting gravitational force in the linear plant model. Requirement of pseudo trim condition for force balance is described in the paper. The paper highlights the commands to be tracked and variables to be fed back during different regimes of re-entry flight. Issues in control law gain design with respect to selected sensors and their placement are elaborated in the paper. Insights on the aspect of trim scheduling, gain scheduling, and finalization of control law structure are also given in the paper.

Reconfiguration and optimization of flight control system based on multi-model adaptive method

For the reconstruction problem of the flight control law when aircraft actuator was damaged or in failure cases,a new reconfiguration scheme of flight control system was proposed based on the linear quadratic optimal control theory and multi-model adaptive method.Based on fault diagnosis and detection technology,the reference model was obtained by the Linear Quadratic Regulator(LQR).Lyapunov stability theory was applied to ensure the strictly positive real parts and global asymptotic stability of the closed-loop control system.According to the vehicle dynamics control law for fault identification and model switching,the reconfiguration and optimization of vehicle control law based on the multi-model adaption was designed.Against the typical fault conditions,the reconfiguration simulation of the flight control system was made to verify the method,and the corresponding verification results were given,which can ensure that the aircraft effective operation.

Hierarchical Motion Planning With Dynamical Feasibility Guarantees for Mobile Robotic Vehicles

Motion planning for mobile vehicles involves the solution of two disparate subproblems: the satisfaction of high-level logical task specifications and the design of low-level vehicle control laws. A hierarchical solution of these two subproblems is efficient, but it may not ensure compatibility between the high-level planner and the constraints that are imposed by the vehicle dynamics. To guarantee such compatibility, we propose a motion-planning framework that is based on a special interaction between these two levels of planning. In particular, we solve a special shortest path problem on a graph at a higher level of planning, and we use a lower level planner to determine the costs of the paths in that graph. The overall approach hinges on two novel ingredients: a graph-search algorithm that operates on sequences of vertices and a lower level planner that ensures consistency between the two levels of hierarchy by providing meaningful costs for the edge transitions of a higher level planner using dynamically feasible, collision-free trajectories.

A theory of traffic flow in automated highway systems

This paper presents a theory for automated traffic flow, based on an abstraction of vehicle activities like entry, exit and cruising, derived from a vehicle's automatic control laws. An activity is represented in the flow model by the space and time occupied by a vehicle engaged in that activity. The theory formulates Traffic Management Center (TMC) plans as the specification of the activities and velocity of vehicles, and the entry and exit flows for each highway section. We show that flows that achieve capacity can be realized by stationary plans that also minimize travel time. These optimum plans can be calculated by solving a linear programming problem. The theory permits the study of transient phenomena such as congestion, and TMC feedback traffic rules designed to deal with transients. We propose a “greedy” TMC rule that always achieves capacity but does not minimize travel time. We undertake a microscopic study of the “entry” activity, and show how lack of coordination between entering vehicles and vehicles on the main line disrupts traffic flow and increases travel time. We conclude by giving some practical indication of how to obtain the space and time usage of activities from vehicle control laws. Finally, we illustrate the concepts presented in this paper with two examples of how the model is used to calculate the capacities of a one-lane automated highway system. In one example we study market penetration of adaptive cruise control and in the second example we study the effect of platooning maneuvers in a platooning architecture for AHS.

Longitudinal control of the lead car of a platoon

Presents longitudinal control laws for vehicles moving in an intelligent vehicle highway system (IVHS). In particular, the scenario where cars move along the highway in tightly spaced platoons is considered. The authors present control schemes that perform the major longitudinal tasks that will be required from the lead vehicle of a platoon moving on an automated highway. More specifically, schemes that maintain safe spacing, track an optimal velocity and perform various maneuvers (forming, breaking up platoons and changing lanes) are described. Simulation results are given. >

Digital Controllers for VTOL Aircraft

Using linear-optimal estimation and control techniques, digitaladaptive daptive control laws have been designed for a tandem-rocopteror heliopter which is equipped for fully automatic flight in terminal area operations. Two distinct discrete-time control laws are designed to interface with velocity-command and attitude-command guidance logic, and each incorporates proportional-integral compensation for nonzero-set-point regulation, as well as reduced-order Kalman filters for sensor blending and noise rejection. Adaptation to flight condition is achieved with a novel gain-scheduling method based on correlation and regression analysis. The linear-optimal design approach is found to be a valuable tool in the development of practical multivariable control laws for vehicles which evidence significant coupling and insufficient natural stability.