Yaw Acceleration Research Articles

A Novel Tyre Force Distribution Method for Four-Wheel Independent Driving Vehicles

This paper discusses an optimal algorithm for distributing tyre force by an analytical multiplier penalty function method with which the maneuverability and stability of the four-wheel independent driving vehicles can be improved. Based on hierarchical method, the controller is divided into the upper level and lower level one. In the upper level controller, the yaw moment is calculated by sliding control to track the desired yaw rate. In the lower level controller, the analytical multiplier penalty method is utilized to distribute the yaw moment to tyre forces according with equality constraints of yaw and longitudinal acceleration. Simulation was conducted with Matlab/Simulink and Carsim. Simulation results show that the proposed method is effective.

The relationship between vehicle yaw acceleration response and steering velocity for steering control

This paper proposes a novel concept for the modelling of a vehicle steering driver model for path following. The proposed steering driver reformulates and applies the Magic Formula, used for tyre lateral force vs. slip angle modelling as a function of vertical force, to the vehicle’s yaw acceleration vs. steering velocity response as a function of vehicle speed. The path-following driver model was developed for use in gradient-based mathematical optimisation of vehicle suspension characteristics for handling. Successful application of gradient-based optimisation depends on the availability of good gradient information. This requires a robust driver model that can ensure completion of the required handling manoeuvre, even when the vehicle handling is poor. The steering driver is applied to a nonlinear full vehicle model of a sports utility vehicle, performing a severe double lane change manoeuvre. Simulation results show excellent correlation with test results. The proposed driver model is robust and well suited to gradient-based optimisation of vehicle handling.

Staying within the nullcline boundary for vehicle envelope control using a sliding surface

Envelope control has been implemented successfully in aircraft for over a decade to assist pilots in stabilising their planes. With current advances in sideslip angle and friction coefficient estimation, envelope control can now be applied to the automotive industry as well. Using full state estimation of yaw rate and sideslip angle, stability controllers can assist the driver by keeping the vehicle within a safe region of the planar state space. This paper discusses the physical phenomena that must be taken into account when choosing an envelope and details a specific choice of envelope comprised of the yaw acceleration nullcline and the maximum rear slip angle limits. The vehicle is kept within the envelope using a computationally simple sliding surface control scheme. Experimental data show the success of the controller, which is implemented on a vehicle through the use of steer-by-wire.

Strait-line Tracking Control of Under-actuated Ship

High performance path following control, especially straight line path tracking, is one of the most difficult problems in autonomous control of under-actuated ship. In this paper, we propose a straight line path following control algorithm by combining adaptive yaw angle feedback, back-stepping and acceleration feedback technique together. The most absorbing advantage of the proposed controller is that it not only reserves the good performance of back-stepping controller and bring much faster convergent rate, but also eliminates the disturbance impacts, which is very important in real applications. The simulation results with respect to a training ship model have shown the feasibility and validity of the proposed method.

Discussion on: “Experimental Identification of Engine-to-Slip Dynamics for Traction Control Applications in a Sport Motorbike”

Vehicle dynamics is today of great importance in automo- tive industry. Indeed, over the past few years, automo- tive engineering has been characterized by rapid growth in active systems. Many research works have therefore been devoted to the control of such active subsystems, as braking, steering or suspension actuators. In particular the control of suspension systems still remains of interest since this subsystem in uences comfort and road handling as well [1, 2, 3]. More recently the use of di erent actua- tors (braking, steering, suspension ...) has shown to allow for emergency situations such as rollover, too large lateral and yaw accelerations, slipping .... [4, 5, 6]. However, as emphasized by Matteo Corno and Sergio Savaresi much less work have been devoted to motorbike control, in particular in sport industry. The aim of the paper is then to bring some contribution for Traction Con- trol applications. Indeed some new methodology for ex- perimental identi cation of engine-to-slip dynamics is pro- posed, leading to the analysis of the interest of throttle or spark-advance actuators for slip control respectively. First, the authors present two algorithms that can be used for wheel speed measurements. It is emphasized that both solutions lead to some estimation delays, which de- pends on the type and chracteristics of the sensor. The core of the paper concern the identi cation of engine-to- slip dynamics using as input variable, either the throttle position, or the spark advance. First it has been shown in this paper that the modelling of the throttle-to-slip system can be approached by a switch- ing system with two modes, since it better approximates the full harmonics model. Then the delay issue has been discussed and the im- portance of taking into account the time-delay in con- trol design has been emphasized. It appears that some recent methodologies in observation and control of time- delay systems, could be planned, as the ones proposed in [11, 12, 13].

Application of Recursive Least Square Algorithm on Estimation of Vehicle Sideslip Angle and Road Friction

A recursive least square (RLS) algorithm for estimation of vehicle sideslip angle and road friction coefficient is proposed. The algorithm uses the information from sensors onboard vehicle and control inputs from the control logic and is intended to provide the essential information for active safety systems such as active steering, direct yaw moment control, or their combination. Based on a simple two-degree-of-freedom (DOF) vehicle model, the algorithm minimizes the squared errors between estimated lateral acceleration and yaw acceleration of the vehicle and their measured values. The algorithm also utilizes available control inputs such as active steering angle and wheel brake torques. The proposed algorithm is evaluated using an 8-DOF full vehicle simulation model including all essential nonlinearities and an integrated active front steering and direct yaw moment control on dry and slippery roads.

Nonlinear control concepts for a UA

A reconfigurable flight control method is developed to be implemented on an Unmanned Aircraft (VA), a thirty percent scale model of the Cessna 150. This paper presents the details of the UA platform, system identification, reconfigurable controller design, development, and implementation on the UA to analyze the performance metrics. A Crossbow Inertial Measurement Unit provides the roll, pitch, and yaw accelerations and rates along with the roll and pitch. The 100-400 mini-air data boom from SpaceAge Control provides the airspeed, altitude, angle of attack, and the side slip angles. System identification is accomplished by commanding preprogrammed inputs to the control surfaces and correlating the corresponding variations at the outputs. A Single Network Adaptive Critic, which is a neural network-based optimal controller, is developed as part of a nonlinear flight control system. An online learning neural network is augmented to form an outer loop to reconfigure and supplement the optimal controller to guarantee a "practical stability" for the airplane. This paper also presents some simulations from the hardware-in-the-loop testing and concludes with an analysis of the flight performance metrics for the controller under investigation.

Global vehicle control using differential braking torques and active suspension forces

This article treats the problem of global chassis control of a wheeled-vehicle in a turn. The aim of our research is to design a nonlinear control law that allows the vehicle to follow the desired trajectories in yaw rate and in longitudinal acceleration while stabilizing the behaviours of roll rate, pitch rate and vertical velocity using both braking torques and suspension forces. The research is realized under the collaboration of the Centre de Robotique of the École des Mines de Paris with PSA-Peugeot-Citroën. The global control problem is divided into two subproblems depending on the physical control actuators which are used. First, in the case of horizontal dynamics control, only the braking torques are used. Then, in the second case of vertical dynamics control, only the suspension forces are used. In this case, we show that the system loses its controllability property during the transition phase of the turn, if we consider explicitly the yaw acceleration equation to compute the suspension forces. An alternative solution is proposed, which can regulate the pitch rate, roll rate and vertical velocity, and can act on the yaw rate by adapting a constrained optimal control algorithm. Then the two control subproblems are merged into a global chassis control which achieves our aim. The above mentioned control laws are based on the technique of nonlinear constrained optimization and of singular perturbations theory using natural time scale decomposition in slow/fast subsystems. They have been tested and validated on a complete vehicle model of 14 degrees of freedom developed by PSA-Peugeot-Citroën.

Multi-Objective Optimization of the Handling Performances of a Road Vehicle: A Fundamental Study on Tire Selection

The optimization of the handling behavior of road vehicles is dealt with in this paper. Both a linear and a nonlinear model have been considered. A number of analytical solutions to the equations of motion have been derived for the linear model. The objective functions (i.e. performance indices) to be optimized for a steering step input maneuver were the sideslip angle gain, the yaw velocity peak response time, the yaw velocity overshoot and the initial yaw acceleration. The front and rear tire cornering stiffness have been considered as the design variables to be optimized. The derived optimal solutions can be used during preliminary design for the definition of the best vehicle handling performance. The tire cornering stiffness of a number of actual road vehicles comply with the corresponding values coming from the optimization process proposed in the paper.

Vestibular catch-up saccades in labyrinthine deficiency.

During rapid head rotations, saccades ipsiversive with compensatory vestibulo-ocular reflex (VOR) slow phases may augment the deficient VOR and assist gaze stabilization in space. The present experiments compared these vestibular catch-up saccades (VCUSs) with visually and memory-guided saccades. To characterize VCUSs and their relationship to deficiency of the initial VOR, we delivered random, whole-body transients of 1000 and 2800 degrees/s2 peak yaw acceleration around four different eccentric vertical axes in eight unilaterally and one bilaterally vestibulopathic subjects, as well as nine age-matched normal subjects. Eye and head movements were sampled at 1200 Hz using magnetic search coils. Subjects fixed targets at either 500 or 15 cm distance immediately before unpredictable onset of rotation in darkness. Under all testing conditions, normal subjects exhibited only compensatory vestibular slow phases and occasional anticompensatory quick phases. This behavior was also typical of unilaterally vestibulopathic subjects rotated contralesionally. When rotated ipsilesionally, however, vestibulopathic subjects had deficient slow-phase VOR gain with prolonged latency, and six of the nine exhibited saccadic movements in the compensatory direction (VCUSs). Higher head accelerations preferentially evoked VCUSs, but there were no preferred combinations of target distances and eccentric rotation axes. Peak velocities and durations of VCUSs increased with saccade amplitude. The latency distribution for VCUSs peaked around 70 ms, substantially shorter than reported for either visually guided express saccades or vestibular memory contingent saccades. The latency of each VCUS was highly correlated with the gaze error prior to that VCUS. The amplitude of VCUSs was calibrated to gaze position error, such that VCUSs reduced gaze error by an average of 37%. Thus when VOR slow-phase responses cannot compensate fully for head rotation, vestibular gaze position error can nevertheless calibrate the programming of VCUSs to augment the deficient VOR, much like catch-up saccades substitute for deficient visual pursuit.

STEERING OF 4WD VEHICLES WITH INDEPENDENT WHEEL TORQUE CONTROL

This paper investigates the steering performance of a new configuration of automotive vehicles-4WD vehicles with independent wheel torque control (IWTC). The vehicle model has no steer linkages and a turning manoeuvre can be realised by controlling the wheel torque at each wheel to give a tyre speed differential between the outside and inside tyres. The wheel torque difference between the outside and inside tyres, which controls the tyre velocity difference, is a function of the handwheel angle and the error between the expected yaw rate and the measured yaw rate. In order to control steer stability, a stability compensator for tyre/road adhesion limit is developed and the yaw rate and yaw acceleration are used as control variables. This strategy first evaluates the vehicle stability and then reacts depending on whether the stability criteria is satisfied. The study shows that IWTC vehicles can be well steered by applying the methods developed in this research.

STEERING OF 4WD VEHICLES WITH INDEPENDENT WHEEL TORQUE CONTROL

Abstract This paper investigates the steering performance of a new configuration of automotive vehicles-4WD vehicles with independent wheel torque control (IWTC). The vehicle model has no steer linkages and a turning manoeuvre can be realised by controlling the wheel torque at each wheel to give a tyre speed differential between the outside and inside tyres. The wheel torque difference between the outside and inside tyres, which controls the tyre velocity difference, is a function of the handwheel angle and the error between the expected yaw rate and the measured yaw rate. In order to control steer stability, a stability compensator for tyre/road adhesion limit is developed and the yaw rate and yaw acceleration are used as control variables. This strategy first evaluates the vehicle stability and then reacts depending on whether the stability criteria is satisfied. The study shows that IWTC vehicles can be well steered by applying the methods developed in this research.

Land Vehicle Roll/Yaw Product of Inertia Measurement

This paper focuses on the measurement of the roll/yaw product of inertia of a vehicle and describes a four-degree-of-freedom lumped-parameter ADAMS model used to simulate the test configuration. The measurement is performed by oscillating the vehicle in yaw and monitoring the resulting yaw acceleration and roll torque. The product of inertia is calculated from equations representing the motion of a rigid body relative to a nonmoving reference frame modified to accommodate for the misalignment of the vehicle center of gravity and the test apparatus yaw axis, and to approximate the compliant behavior between the test device and vehicle. The effects of the vehicle center of gravity misalignment from the test apparatus’ yaw axis and the compliance between the test vehicle and test device are studied. The measurement uncertainty is found using the law of propagation of uncertainty.

Fighter aircraft lateral directional axes full envelope control law design

A decoupled wide envelope lateral/directional axes control design is presented for a supermanoeuvrable version of an F-18 aircraft. A control structure is developed that separates gain scheduling issues from aircraft performance issues. Flight condition dependent state and control effectiveness variations are accounted for by an inner loop controller designed using eigenstructure assignment. Structured singular value synthesis is used to design an implicit model following outer loop controller that addresses flying qualities performance specifications. A control selector is designed that generates lateral/directional aerodynamic and thrust vectoring commands from generalized control inputs of roll and yaw acceleration. Flying qualities and robustness analyses show that the control system performs well despite neglected dynamics and system uncertainties. Nonlinear simulations are presented showing excellent decoupling of roll and yaw responses.

Some aspects of a realistic three-dimensional pursuit-evasion game

A three-dimensio nal pursuit-evasion game between a realistic missile and an aircraft is studied employing point-mass models for both vehicles. Since a direct method to solve this complicated mini-max problem is too time-consuming, the study is conducted by carrying out massive simulations in the parameter space of initial conditions and guidance law parameters. The important role of information in the opponent's acceleration to the game and the effectiveness of the strategy in rotating the line-of-sight vector are shown. It is found that there exist very few cases where the aircraft can avoid the missile, among them typical air-combat maneuvers such as linear acceleration, high-£ barrel roll, split-S, and horizontal-S. Nomenclature flcmax = missile lateral acceleration command limit Ompjdmy = missile acceleration components measured in aircraft pitch and yaw axis, respectively ^p^y^pc^yc = missile-pitch and yaw-axis lateral accelerations and their command signals OpttOyt = aircraft-desir ed pitch and yaw acceleration components, respectively Otp9oty = aircraft acceleration components measured in missile pitch and yaw axis, respectively CD = drag coefficient CDO

Optimal Control Model Applications and Field Measurements with Respect to Car Driving

ABSTRACT The well-known optimal control model has been applied only rarely to car driving, although its structure suits the modelling demands of driving by allowing for a multitask application and providing possibilities for the evaluation of driving in terms of supervisory control. Two series of Supervisory Driver Model predictions are stated for lateral position control in a straight driving scenario with disturbances generated internally by the driver. The first series of model calculations predicts lateral position variations and the time that a driver's vision can be occluded during the observation and control of different combinations of display variables (lateral position, lateral speed, yaw rate, lateral acceleration and yaw acceleration). The second series of predictions concerns two extreme sets of display variables in relation to driving speed and driving experience. Model predictions for the observation and control of all display variables give occlusion times which correspond with data from i...

Optimum angular accelerations for control of a remote maneuvering unit.

Six Ss successfully reoriented the attitude of a simulated remote maneuvering unit (RMU) using an on-off acceleration command control system. RMU attitude was determined solely by viewing the space scene being televised by the RMU. The RMU was controlled under three conditions of angular acceleration; 4, 8, and 12° / sec.2. Four deg/sec2 resulted in least fuel expenditure and most accurate rate control without a sacrifice in time. These results and Ss' preference data recommended pitch, yaw, and roll accelerations of 4°/sec2 when using an on-off acceleration command control system.