Estimation of Vehicle Longitudinal Speed Based on Improved Kalman Filter

Estimation of vehicle longitudinal acceleration is very important in vehicle active safety control system. In this paper, two driving conditions of a 4WD off-road vehicle are divided by vehicle signals such as steering angle. Under different working conditions, different estimation algorithms are adopted. In the straight driving condition, the longitudinal speed was estimated by adjusting the variance weight of acceleration Kalman observation noise based on kinematics method. For steering conditions, in order to obtain the longitudinal velocity at the center of mass, by dynamic method, a lateral state estimator was designed and tire sideslip dynamics was modeled. The CarSim-Simulink co-simulation results show that the proposed algorithm has high accuracy and strong practicability.

Vehicle State Estimation Based on Strong Tracking Central Different Kalman Filter

Vehicle active safety control was a key technology to avoid serious safety accidents, and accurate acquisition of vehicle states signals was a necessary prerequisite to achieve active vehicle safety control. Based on the purpose, a 3-DOF nonlinear vehicle dynamics model containing constant noise and a nonlinear tire model were established, and several vehicle key states were estimated by a strong tracking central different Kalman filter (CDKF). The conclusion showed that the proposed estimator had higher accuracy and less computation requirement than the CKF, CDKF, and UKF estimators. Numerical simulation and experiments indicated that the proposed vehicle state estimation method not only had higher estimation accuracy but also had higher real-time function.

A Novel V2V Cooperative Collision Warning System Using UWB/DR for Intelligent Vehicles

The collision warning system (CWS) plays an essential role in vehicle active safety. However, traditional distance-measuring solutions, e.g., millimeter-wave radars, ultrasonic radars, and lidars, fail to reflect vehicles’ relative attitude and motion trends. In this paper, we proposed a vehicle-to-vehicle (V2V) cooperative collision warning system (CCWS) consisting of an ultra-wideband (UWB) relative positioning/directing module and a dead reckoning (DR) module with wheel-speed sensors. Each vehicle has four UWB modules on the body corners and two wheel-speed sensors on the rear wheels in the presented configuration. An over-constrained localization method is proposed to calculate the relative position and orientation with the UWB data more accurately. Vehicle velocities and yaw rates are measured by wheel-speed sensors. An extended Kalman filter (EKF) is applied based on the relative kinematic model to combine the UWB and DR data. Finally, the time to collision (TTC) is estimated based on the predicted vehicle collision position. Furthermore, through UWB signals, vehicles can simultaneously communicate with each other and share information, e.g., velocity, yaw rate, which brings the potential for enhanced real-time performance. Simulation and experimental results show that the proposed method significantly improves the positioning, directing, and velocity estimating accuracy, and the proposed system can efficiently provide collision warning.

Parameterization of the ABS electronic control unit for increasing the autonomous trucks’ active safety

The article is devoted to the issue of improving the autonomous vehicles safety. The anti-lock braking system was chosen as the object of the study, since it is one of the components of the vehicle active safety during emergency braking. Its functioning varies depending on parameters such as vehicle type, transmission type, external and internal steering wheel angles. It is necessary to parameterize correctly the electronic control unit of the anti-lock braking system depending on the specific values of these parameters. For this, a software module was developed that reads the values of the vehicle parameters from a file and sends their array to the electronic control unit. Then we can check the result: how the block responded to the sent request -positively or negatively. All this will speed up the parameterization process, increase its accuracy, preventing the occurrence of operator errors during its implementation.

A review of vehicle active safety control methods: From antilock brakes to semiautonomy

A comprehensive review of technologies and approaches for active safety systems designed to reduce ground vehicle crashes, as well as the associated severity of injuries and fatalities, is provided. Active safety systems are commonly referred to as systems that can forewarn a driver of a potential safety hazard, or automatically intervene to reduce the likelihood of an accident without requiring driver intervention. The data from naturalistic drivers has shown that such systems are instrumental in improving vehicle safety in various conditions, particularly at higher speeds and under adverse road conditions. The increased integration of sensors, electronics, and real-time processing capabilities has served as one of the critical enabling elements in the widespread integration of active safety systems in modern vehicles. The emphasis is placed on control approaches for active safety systems and their progression over the years from antilock brakes to more advanced technologies that have nearly enabled semiautonomous driving. A review of key active safety control approaches for antilock braking, yaw stability, traction control, roll stability, and various collision avoidance systems is provided.

Delay compensated pneumatic brake controller for heavy road vehicle active safety systems

Performance enhancement of typically sluggish pneumatic brake actuators in Heavy Commercial Road Vehicles (HCRVs) is necessary for the efficacious operation of active safety systems. This study develops a robust Proportional Integral Derivative (PID) controller using the Kharitonov theorem for pneumatic brakes. To account for the inherent time delay present in pneumatic brakes, Padé approximation and state prediction methods were used. The efficacy of the brake controller when used for active safety system operation has been investigated by conducting Hardware-in-Loop (HiL) experiments. It was found that state prediction based design turned out to be a better choice for handling time delays in the brake actuator. This controller was then compared with a Sliding Mode Control (SMC) based brake controller and the performance of both controllers was comparable. Further, the state prediction based PID brake controller was found to be robust up to 100% variation in system time constant and 40% variation in time delay for different road and load conditions.

Review of Vehicle Active Safety Systems and their coordinated control

Background: All the time, the safety of the vehicle has been valued by all the world's parties, whether it is now or in the future, the automobile safety issue is the hotspot and focus of the research by experts and scholars. The continuous increase of car ownership brings convenience to people's life and also poses a threat to people's life and property security. Vehicle active safety system is the hotspot of current research and development, which plays an important role in automobile safety. Firstly, the vehicle active safety technology and its development situation was introduced, then Ref. review was carried out about Anti-Lock Brake System (ABS), Electronic Brake force Distribution (EBD/CBC), Brake Assist System (BAS/EBA/BA), Traction Control System (TCS/ASR), Vehicle Stability Control (VSC/ESP/DSC), etc. At present, there are many patents on the control of each subsystem, but few patents on the integrated control for the active safety of vehicles. Objective: The main contents of this paper are as follows: the control strategies and methods of different active safety systems, how to improve the stability of vehicle control and ensure the effectiveness of active safety system control. It provides a reference for the development of active safety control technology and patent. Methods: Through the analysis of different control algorithms and control strategies of Anti-lock and braking force distribution systems, it is pointed out that the switching of EBD/ABS coordinated control strategy according to slip rate can make full use of slip rate and road adhesion coefficient to improve the safety of the system. For the BAS, the slip problem is solved through the combination of Mechanical Assistant Braking System (MABS) and Electronic Braking Assistant (EBA) system by measuring the distance of the vehicle ahead and the speed of the vehicle ahead. The optimal slip rate control is realized by different control algorithms and control strategies of traction control system. It is pointed out that the adaptive fuzzy neural controller should be used to control the yaw angular velocity and centroid side angle of Electronic Stability Program (ESP), which has a good effect on maintaining vehicle stability. A sliding mode variable structure controller combined with constant speed control and approach law control is used to control the yaw moment. Results: Through the coordinated control strategy of EBD/ABS, the slip rate and road adhesion coefficient were fully utilized by switching according to slip rate. The problem of sliding slope is solved by MABS with EBA system. The ESP should use adaptive fuzzy neural controller to control the yaw angular velocity and centroid side angle, and adopt the joint sliding mode variable structure controller which combines the ABS control and the yaw moment control. Through the optimal control theory, the coordinated control of each subsystem can significantly improve the driving stability, riding comfort, fuel economy and so on. Conclusion: This adopt different control strategy and control algorithm for different active safety control system and make full use of tire-road friction coefficient and slip ratio optimal slip ratio, then it realized accurate control of control variables such as yawing angular velocity, centroid side-slip angle, yawing moment and finally ensure the vehicle braking stability, robustness of the controller and the lateral stability of vehicle.

Robust Estimation of Vehicle Motion States Utilizing an Extended Set-Membership Filter

Reliable vehicle motion states are critical for the precise control performed by vehicle active safety systems. This paper investigates a robust estimation strategy for vehicle motion states by feat of the application of the extended set-membership filter (ESMF). In this strategy, a system noise source is only limited as unknown but bounded, rather than the Gaussian white noise claimed in the stochastic filtering algorithms, such as the unscented Kalman filter (UKF). Moreover, as one part of this strategy, a calculation scheme with simple structure is proposed to acquire the longitudinal and lateral tire forces with acceptable accuracy. Numerical tests are carried out to verify the performance of the proposed strategy. The results indicate that as compared with the UKF-based one, it not only has higher accuracy, but also can provide a 100% hard boundary which contains the real values of the vehicle states, including the vehicle’s longitudinal velocity, lateral velocity, and sideslip angle. Therefore, the ESMF-based strategy can proffer a more guaranteed estimation with robustness for practical vehicle active safety control.

Stand for cyclic tests of rack and pinion steering mechanism

At the present moment the motor vehicle designers pay particular attention to the vehicle active safety aspects. Steering control plays a significant role here, since its slightest malfunction may result in very unpleasant consequences. Therefore, specific attention is paid to the improvement of the steering control quality and reliability. This article presents the design of a stand for testing steering mechanisms of various dimensions through application of torque at numeral angles; the torque application aims to improve the vehicle active safety.