Active Steering System Research Articles

An artificial neural network-based integrated tilt control system for narrow electric three-wheelers

The active tilt-controlled narrow electric three-wheelers offer an encouraging solution to pressing environmental and urban challenges, including air and noise pollution, parking shortage, and traffic congestion while improving their rollover stability. The previous research on active tilt control established a desired tilt angle neglecting track width which helps to bear unbalanced lateral acceleration that leads to rollover threat. This article proposes a dynamic rollover index based optimal tilting approach, which tilts the vehicle only when rollover index reaches beyond the desired optimal threshold values. Furthermore, the present work introduces an optimal active tilt control strategy, integrating tilt control system with an active steering system. The proposed integrated tilt control system optimizes an active steering gain with the objective to minimise the deviation in the desired trajectory. The proposed control system ensures the manoeuvrability and rollover stability at higher speed up to 100 km/hr with 22° steering angle even when vehicle reaches its tilt limit. Matlab/Simulink has been used in this study to thoroughly investigate the vehicle dynamics model and proposed integrated active tilt control system. The proposed control strategy is found to be more effective than the traditional steering direct tilt control approach. An artificial neural network that avoids the control system’s complexity and provides a faster response was also studied. The investigation showcases the efficacy of augmenting the dataset length and increasing neurons in the network’s hidden layers. The performance metrics of the trained model tested on the external data imply that the model holds significant potential for practical applications.

Planning lane changes using advance visual and haptic information.

Taking a motor planning perspective, this study investigates whether haptic force cues displayed on the steering wheel are more effective than visual cues in signaling the direction of an upcoming lane change. Licensed drivers drove in a fixed-base driving simulator equipped with an active steering system for realistic force feedback. They were instructed to make lane changes upon registering a directional cue. Cues were delivered according to the movement precuing technique employing a pair of precues and imperative cues which could be either visual, haptic, or crossmodal (a visual precue with a haptic imperative cue, and vice versa). The main dependent variable was response time. Additional analyses were conducted on steering wheel angle profiles and the rate of initial steering errors. Conditions with a haptic imperative cue produced considerably faster responses than conditions with a visual imperative cue, irrespective of the precue modality. Valid and invalid precues produced the typical gains and costs, with one exception. There appeared to be little cost in response time or initial steering errors associated with invalid cueing when both cues were haptic. The results are consistent with the hypothesis that imperative haptic cues facilitate action selection while visual stimuli require additional time-consuming cognitive processing.

A Basic Study for Active Steering Wheel System for Steering Burden Evaluation by Driving Position Focus on Driver’s Arm Size

As automated driving has not yet been established, on narrow roads where there is no separation between pedestrians and vehicles, it is essential to switch to manual driving. However, when the driver turns the steering wheel from one hand to another on narrow roads, it causes steering burdens and operational errors if the steering feel or burden is not proper. Thus, this study aims to construct an active steering wheel system that provides an appropriate steering feel or burden by controlling the steering reaction torque, driving position and steering gear ratio for each driver. In this paper, we focused on and examined the driving position among these. A two-dimensional steering model that considers the size of the arms for each driver was established to evaluate steering burden. In addition, a basic study was conducted on the appropriate driving position. Then, based on the joint movements and angles calculation, the appropriate driving position that considers the size of the arms was studied by evaluating the joint power. As a result, it was found that if the steering wheel position is too close to the driver, the amount of joint movement increases, and if it is too far away, the joint movement decreases. Therefore, it was found that the appropriate steering wheel position for each driver’s arm length can be considered by using the joint power.

Motorcycle emergency steering assistance: A systematic approach from system definition to benefit estimation and exploratory field testing

Braking assistance systems are already contributing to improving motorcyclists’ safety, however, research on emergency systems acting on the steering is lacking. These systems, already available for passenger cars, could prevent or mitigate motorcycle crashes in which safety functions based only on braking are ineffective. The first research question was to quantify the safety impact of diverse emergency assistance systems acting on the steering of a motorcycle. For the most promising system, the second research question was to assess the feasibility of its intervention using a real motorcycle.Three emergency steering assistance systems were defined in terms of Functionality, Purpose, and Applicability: Motorcycle Curve Assist (MCA), Motorcycle Stabilisation (MS), and Motorcycle Autonomous Emergency Steering (MAES). Experts evaluated each system’s applicability and effectiveness based on the specific crash configuration (using Definitions for Classifying Accidents — DCA), the Knowledge-Based system of Motorcycle Safety (KBMS), and the In-Depth Crash Reconstruction (IDCR). An experimental campaign was conducted with an instrumented motorcycle to assess the rider’s reaction to external steering input. A surrogate method for an active steering assistance system imparted external steering torques in correspondence with a lane change to analyse the effect of the steering inputs on motorcycle dynamics and rider controllability.MAES globally got the best score for each assessment method. MS received better evaluations than MCA in two out of three methods. The union of the three systems covered a sizeable fraction of the crashes considered (maximum score in 22.8% of the cases). An estimation of the injury potential mitigation, based on injury risk functions for motorcyclists, was made for the most promising system (MAES). The field test data and video footage showed no instability or loss of control, despite the high intensity (>20Nm) of the external steering input. The rider interviews confirmed that the external action was intense but manageable.For the first time, this study presents an exploratory assessment of the applicability, benefits, and feasibility of motorcycle safety functions acting on the steering. MAES, in particular, was found applicable to a relevant share of crashes involving motorcycles. Remarkably, applying an external action to produce a lateral avoidance manoeuvre proved feasible in a real-world test setting.

Effect of steering reaction torque of ultra-compact electric vehicle on steering burden for active steering wheel system

An ultra-compact electric mobility vehicle cannot be equipped with power steering, and the physical burden is large. Therefore, we are continuously researching steering support for an ultra-compact electric mobility vehicle equipped with a steer-by-wire system (SBWS). The SBWS has not been widely diffused because the steering and front wheels are connected only to electric signals and do not have a high redundancy level. However, the advantage of an SBWS is that the steering reaction torque felt through the steering wheel can be controlled freely. We investigated an active steering wheel system (ASWS) that can control an appropriate steering feeling for each driver by being equipped with SBWS and evaluating the steering burden of each driver. So far, research on the SBWS has been considered to improve operability by transmitting road information and feeding back vehicle motion, however few research on an SBWS considers the physical and mental burden on the driver. In this study, we conducted a fundamental analysis of the effect of the steering reaction torque on the steering burden, focusing on the operating direction of the steering wheel.

Simulation-based study on active tilt controlled narrow tilting three-wheeler considering road bank angle

The issues like traffic congestion, parking space and vehicular emission can be reduced by adopting electric narrow tilting three-wheelers, which can also provide a cost-effective and safe mode of transport for low-income people. According to energy technology perspectives 2017, well-to-wheel global greenhouse gas emissions can be reduced up to 1.3 GtCO2-eq by 2060 by adopting electric mobility. This study presents a new and modified SDTC strategy and performance parameters that takes Road Bank Angle (RBA) into account so as to exhibit the adverse effects on rollover safety, ride comfort in terms of the perceived lateral acceleration and desired trajectory. Besides, this study identifies the importance of the RBA consideration in active tilt controlled vehicle for the scenario of parking on sloped surface. Simple electronic control architecture of the SDTC approach with real-time RBA consideration is proposed to address the limitations of SDTC and its supplementary advantages. This study evaluates the scenario of constant turn manoeuvre and vehicle parking on the banked roads. A multi-body model is used to capture the dynamic characteristics of the vehicle, whereas a characteristic of the Tilt Actuation System (TAS) and Active Steering (AS) system is incorporated in the form of a Transfer Function (TF) estimated using a system identification approach. The results indicate that the inclusion of a real-time RBA in the SDTC enables it to maintain steady-state torque and perceived lateral acceleration close to zero with the proposed controlled strategy, and it also keeps the vehicle upright on the sloped surface. It may be concluded that RBA compensation improves the ease of handling the vehicle while parking or riding on a sloped surface without significant control system alterations, which also makes it a viable alternative for physically disabled people.

Modeling of a two-axle rail vehicle for state estimation

A two-axle rail vehicle having solid axle wheel-sets is developed by using Kalman filter state estimator. Approximately 18 states (from all the 8 inertial measurements) are observed by developing a Kalman filter. A total of five gyroscopes and three accelerometers calibrate the lateral acceleration, yaw velocity of the vehicle and two wheel-sets roll velocity. All the vehicle states are observed by formulating the Kalman filter, moreover, the Kalman filter is also used to calculate the different parameters like cant angle and radius of the curvature of the track. The design of the rail vehicle is validated by comparing the actual results with the same from computer simulations. The simulation also helps to develop an optimal and novel controller to assess the performance of the design of an active steering system.

Lateral Misalignment and Yaw Angle Control Considering Vehicle Dynamics Based on Receiving Energy in Dynamic Wireless Power Transfer

Recently, dynamic wireless power transfer (DWPT) has been shown to be a promising technology for the widespread of electric vehicles (EVs). To utilize this technology, a critical challenge is to eliminate the coil misalignments, which cause a decrease in the coupling coefficient, thereby considerably degrading the power transfer efficiency. Considering the rectangular coils, this paper presents a new method to estimate and eliminate lateral misalignments. Based on the dynamics model of the vehicle, the lateral misalignment is estimated by the fusion of the DWPT current and the onboard inertial measurement unit. On the other hand, the misalignment and the yaw angle of the vehicle are simultaneously controlled by using rear in-wheel motors and the front active steering system. The effectiveness of the proposed method has been demonstrated by both simulations and experiments using a vehicle developed by our research group.

Decentralized integration of constrained active steering and torque vectoring systems to energy-efficient stability control of electric vehicles

In this paper, the optimal driving torques of four wheels in an electric vehicle (EV) are obtained by minimizing the losses of four in-wheel motors. In order to slightly change these optimal torques for vehicle stability recovery, a new constrained active front steering (AFS) system is analytically designed and integrated with the torque vectoring (TV) system in a novel decentralized structure. In the proposed structure, the required external yaw moment is applied by the TV controller only when the constrained AFS is filled to capacity determined by a stability index extracted from the nonlinear phase plane analysis. As a result of this integration strategy, the external yaw moment is used as low as possible. Consequently, the torques in electrical motors are used near the optimal values consistent with optimal energy consumption. Comparative simulation studies with the standalone TV are conducted in the CarSim software environment to show the efficiency of the proposed decentralized control structure in terms of energy consumption and stability. Moreover, the suitability of the constrained control method used in the integration structure is shown in comparison with the well-known nonlinear model predictive control method in terms of practical implementation.

Multiobjective Synchronous Control of Heavy-Duty Vehicles Based on Longitudinal and Lateral Coupling Dynamics

The steering system, suspension system, and braking system of the vehicle are interrelated, so the ride comfort and handling stability of the vehicle are also closely related. But the vertical and lateral dynamics equations and controls system of the vehicle are always independent of each other, and the multiobjective control is generally achieved through the coordination of control algorithms. In this paper, taking the dynamic load of the tire as a link, the vertical dynamic model and the lateral dynamic model of heavy-duty vehicle are coupled. When the heavy-duty vehicle is turning, the proposed coupling model not only reflects the influence of the front wheel angle on the vertical motion and the vertical tire load, but also reflects the unevenness of the road surface on vehicle lateral motion. In order to improve the handling stability and transient safety of the vehicle, a synchronous control system combining six-wheel steering and front wheel active steering is proposed. It solves the problem that it is difficult to effectively track the desired yaw rate for the three-axle all-wheel steering vehicle with the middle rear wheel angle as the control input. Under the framework of the vehicle vertical/lateral unified coupling dynamics model, the semiactive suspension system controlled by fuzzy PID and the six-wheel active steering system combined with fuzzy control and fuzzy PID control are integrated. It is verified that the synchronous control method effectively optimizes the vertical and lateral motion characteristics of heavy-duty vehicles during steering and, at the same time, improves the ride comfort and steering stability.

A method for evaluating sensitivity of electromagnetic localization systems for wireless capsule endoscopes.

This paper studies the use of electromagnetic induction in localization of wireless capsule endoscopes (WECs). There is still currently a need for an accurate localization system to enable localizing possible findings in the gastrointestinal tract, and to develop an active steering system for the capsule. Developing an optimal localization system requires the sensitivity of the system to be analyzed. In this paper, three different coil geometries are modelled with a computer simulation platform, and their sensitivities and target responses are compared. In order to do that, a formulation for the sensitivity based on the dipole model approximation is presented. The first coil array is based on literature and is used as a reference. The second array presents how having more transmit-receive channels in the array effects the sensitivity. The third coil array simulates the effect of increasing the field excitation intensity in different directions by using a three-axial Helmholtz array. In addition, both proposed coil arrays utilize larger coils than the reference. As a result, it seems that both increasing the coil size and the number of field projections interrogating the target increase the overall sensitivity in the region of interest and the target response. The findings suggest that an optimal coil array could utilize both large coils and multiple transmit-receive channels to increase the number of independent fields incident onto the target.

<b>Development of Active Bogie Steering System to Improve Curving Performance</b>

This paper presents an active steering system designed to ensure both the curving performance and running stability of a vehicle. Electro-hydraulic actuators installed in place of anti-yaw dampers generate a yaw moment between the carbody and bogie. The system detects curves with gyroscopes mounted on the vehicle. This configuration enables the reduction of wheel/rail lateral force without requiring complicated mechanical links in the bogies. The actuators also work as anti-yaw dampers during high-speed running to ensure running stability.

Rail vehicle running safety and steering efficiency evaluation method based on equivalent curvature difference of active steering technology

Active steering technology can effectively solve the contradiction between the running stability and curving performance of traditional bogies. However, the execution deviations between the actual and theoretical steering actions, which expressed in this paper as equivalent curvature differences, would occur when mileage error or other abnormal operating conditions happens. In this study, the influence of equivalent curvature differences on running safety was studied, and a steering efficiency evaluation method was proposed. First, the equivalence between the wheel–rail relationship in the under- and over-steering states and that in the passive state was demonstrated by combining analytical and numerical simulation methods. It was concluded that under- and over-steering states do not worsen the running safety of rail vehicles. Then, the formula for wear number with the equivalent curvature difference as the independent variable was derived based on the linear model of the rail vehicle, and the accuracy of the formula was verified using the nonlinear model. Finally, a steering efficiency evaluation method was established, and a steering efficiency evaluation under different equivalent curvature differences and steering rates was conducted. The results of this study can provide a reference for engineering active steering systems.

Integrated control of electric vehicles based on active front steering and model predictive control

Energy efficiency and handling stability are of the most importance for the control of electric vehicles. It is a challenge to maintain the stability and mobility of the vehicle at the cost of minimum energy under various driving conditions. A novel integrated control strategy of yaw stability and energy efficiency based on model predictive control and active steering system is presented. To improve the energy efficiency of the in-wheel motors, a global search algorithm of the instantaneous optimal efficiency of the motor is used to obtain the optimal torque distribution of the front and rear axles. Meanwhile, a terminal sliding mode controller is presented to maintain the lateral stability of the vehicle under general conditions. To reduce the large additional yaw moment of the vehicle under high-speed cornering condition, the model predictive controller is used to coordinate the active steering system and the direct yaw moment control system. Then, to balance the lateral stability and energy efficiency of the vehicle under extreme conditions, a stability judgment controller is proposed, which based on the theory of phase plane and yaw rate threshold method. The simulation results show that the integrated control strategy can improve the lateral stability of the vehicle under different road friction conditions, and compared with the control strategy without motor efficiency optimization , the integrated control strategy reduces the energy consumption by 21.66% and 11.18% in the ‘sine steering’ and ‘single lane change’ maneuver, respectively. In the slalom maneuver, the energy consumption of the integrated control strategy with energy saving optimization function is reduced by 10.13%.

Lateral Stability Control of Articulated Heavy Vehicles Based on Active Steering System

Lateral Stability Control of Articulated Heavy Vehicles Based on Active Steering System

A Randomized Filtering Strategy Against Inference Attacks on Active Steering Control Systems

In this paper, we develop a framework against inference attacks aimed at inferring the values of the controller gains of an active steering control system (ASCS). We first show that an adversary with access to the shared information by a vehicle, via a vehicular ad hoc network (VANET), can reliably infer the values of the controller gains of an ASCS. This vulnerability may expose the driver as well as the manufacturer of the ASCS to severe financial and safety risks. To protect controller gains of an ASCS against inference attacks, we propose a randomized filtering framework wherein the lateral velocity and yaw rate states of a vehicle are processed by a filter consisting of two components: a nonlinear mapping and a randomizer. The randomizer randomly generates a pair of pseudo gains which are different from the true gains of the ASCS. The nonlinear mapping performs a nonlinear transformation on the lateral velocity and yaw rate states. The nonlinear transformation is in the form of a dynamical system with a feedforward-feedback structure which allows real-time and causal implementation of the proposed privacy filter. The output of the filter is then shared via the VANET. The optimal design of randomizer is studied under a privacy constraint that determines the protection level of controller gains against inference attacks, and is in terms of mutual information. It is shown that the optimal randomizer is the solution of a convex optimization problem. By characterizing the distribution of the output of the filter, it is shown that the statistical distribution of the filter’s output depends on the pseudo gains rather than the true gains. Using information-theoretic inequalities, we analyze the inference ability of an adversary in estimating the control gains based on the output of the filter. Our analysis shows that the performance of any estimator in recovering the controller gains of an ASCS based on the output of the filter is limited by the privacy constraint. The performance of the proposed privacy filter is compared with that of an additive noise privacy mechanism. Our numerical results show that the proposed privacy filter significantly outperforms the additive noise mechanism, especially in the low distortion regime.

Active Steering Wheel System for Ultra-Compact Mobility Vehicles: Operability Evaluation with Steering Burden in Various Drivers

In ultra-compact electric vehicles, the satisfactory installation of an assist mechanism for steering operation is difficult. To address this problem, in this paper, we propose an active steering wheel system in which the steering wheel and tires are electrically connected, without a mechanical connection. Furthermore, in ultra-compact mobility vehicles where the driving position is restricted, steering burden is likely to occur depending on the physique of the driver. However, whether the effects of the steering reaction torque and the amount of steering increase the burden on the driver in such vehicles has not yet been clarified. Therefore, in this study, we developed an upper limb burden model using inverse kinematics and muscle activity to investigate the burden of steering on the driver by considering the driver physique.

Recovering tractor stability from an intensive rollover with a momentum flywheel and active steering: System formulation and scale-model verification

As a representative type of off-road vehicle, agricultural wheeled tractors are driven under varied and complicated road conditions such as plowed and hilly fields. Active control is the essential technique to solve tractor rollover accidents which have been identified as the most fatal incident along with agricultural mechanization. The aim of this study is to provide active correction of tractor attitude in emergency cases by combing a single-axis momentum flywheel system and active steering system. In this study, the time-varying structural nonlinear vehicle dynamic system and its subsystems are formulated during transitions among tractor states under road stimulation. By exploring the phased mutation mechanism of tractor stability, the corresponding stability criteria are proposed. The coordinated tractor safety control strategy was verified using parametric studies in a simulation and scale-model experiments. The results indicated the effective and robust control of tractor safety regarding the independent and integrated active control systems. The proposed approach is expected to provide a theoretical basis and technical support for advanced driver assistance systems applied to future intelligent agricultural vehicles.

Fuzzy and Sliding Mode Variable Structure Control of Vehicle Active Steering System

Background: The safety of vehicles has been valued throughout the world, whether it is now or in the future, the automobile safety issue is the hotspot and focus of the research by experts and scholars both at home and abroad. The continuous increase of car ownership not only brings convenience to people's lives, but it also poses a threat to people's lives and security of the property. Objective: Vehicle active safety system is the hotspot of current research and development as it plays an important role in automobile safety. Through the analysis of patents and references, we aim to understand the development of an active steering system. In order to improve the development efficiency of the active steering system, the paper proposes a feedback control method of the front-wheel angle. Methods: Based on yaw velocity and center of a mass side angle, the Active Front Steering (AFS) model is established respectively by fuzzy control and sliding mode control under the establishment of seven degrees of freedom vehicle dynamics model and the Dugoff tire model. Results: The simulation results show that both the control algorithm of sliding mode control and fuzzy control can improve the handling stability of vehicle steering on high adhesion coefficient road surface. On the low adhesion coefficient road, the control effect of slide mode control is more ideal while fuzzy control caused larger oversteer. Conclusion: The simulation results show that the control effect of sliding mode is superior to fuzzy control.

An Active Steering Hand-held Robotic System for Minimally Invasive Orthopaedic Surgery Using a Continuum Manipulator.

This paper presents the development and experimental evaluation of an active steering hand-held robotic system for milling and curved drilling in minimally invasive orthopaedic interventions. The system comprises a cable-driven continuum dexterous manipulator (CDM), an actuation unit with a handpiece, and a flexible, rotary cutting tool. Compared to conventional rigid drills, the proposed system enhances dexterity and reach in confined spaces in surgery, while providing direct control to the surgeon with sufficient stability while cutting/milling hard tissue. Of note, for cases that require precise motion, the system is able to be mounted on a positioning robot for additional controllability. A proportional-derivative (PD) controller for regulating drive cable tension is proposed for the stable steering of the CDM during cutting operations. The robotic system is characterized and tested with various tool rotational speeds and cable tensions, demonstrating successful cutting of three-dimensional and curvilinear tool paths in simulated cancellous bone and bone phantom. Material removal rates (MRRs) of up to 571 mm3/s are achieved for stable cutting, demonstrating great improvement over previous related works.