This article presents an electronic stability control system that uses active front steering to keep the system state constrained to a subset of the system's lateral stability region with absolutely ...no possibility of failure and safety-critical control based on control barrier functions to obtain the control signal. We propose a method that maximizes the safe set to the largest convex subset of the lateral stability region, rendering the closed-loop system least invasive to the driver's commands. To achieve this, we introduce a safety-critical control formulation that considers exponential control-dependent barrier or Lyapunov functions of arbitrary relative degree. We validate the proposal through commercial vehicle simulation software.
In complex real-world scenarios, wheel-legged robots with maneuverability, stability, and reliability have addressed growing research attention, especially in material transportation, emergency ...rescue, as well as the exploration of unknown environments. How to achieve stable high-level movement with payload delivery simultaneously is the main challenge for the wheel-legged robot. In this article, a novel hierarchical framework for the flexible motion of the six wheel-legged robot is considered in experimental results. First, for the wheeled motion, the speed consensus algorithm is implemented to the six-wheeled cooperative control; for the legged motion, three gait sequences, and foot-end trajectory based on the Bezier function are designed. Furthermore, a whole-body control architecture includes the attitude controller, impedance controller, and center height controller is developed for obstacle avoidance, which can ensure the horizontal stability of the body of the robot when it passes through obstacles in different terrain. Finally, extensive experimental demonstrations using the six wheel-legged robot (BIT-6NAZA) are dedicated to the effectiveness and robustness of the developed framework, indicating that it is a superior case of a selectable flexible motion with satisfactory stable performance under the field world environment.
In this paper, we present selected benchmark aerial manipulation tasks using an aerial vehicle endowed with multi-degree of freedom manipulators. The proposed tasks analyze environmental coupling and ...are broken into three general categories: momentary, loose, and strong coupling. A classical control structure is derived, tuned, and verified through experiments, conducted for benchmarking purposes to include pick-and-place, insertion, and valve-turning tasks. Although other nonlinear controllers may prove more effective, the classical control approach has been selected in order to analyze contact stability and provide benchmark results for future reference. An analysis of system stability is conducted and implemented into the controller. A vision-based high-level controller fuses motion tracking data in order to provide control of both the aircraft and the manipulators, allowing the system to become coupled to the environment and perform the required operation. We present recent results validating our framework using the proposed aircraft-arm system.
•A novel vehicle model is used for yaw rate prediction.•Adaptive model predictive control is developed to improve the yaw stability.•Time-varying model parameters are identified by the unbiased ...estimation.•The performance of the proposed scheme is verified in various scenarios.
In this paper, an adaptive model predictive control (AMPC) scheme with high computational efficiency is developed to improve the yaw stability for four-wheel-independently-actuated electric vehicles (FWIA EVs). A novel vehicle model is first established based on an autoregressive with exogenous input (ARX) model, which is independent of vehicle parameters and road conditions. The time-varying model parameters are identified by an unbiased estimation system via an instrumental variable (IV) method. The AMPC scheme is proposed based on the ARX vehicle model for direct yaw moment control (DYC). Then, a multi-objective optimization method is proposed to optimize torque allocation for yaw stability enhancement. Finally, the performance of the proposed scheme is verified under the double lane change and slalom maneuvers in Carsim. Simulation results show that the ARX-model-based unbiased estimation can effectively follow the reference while filtering out measurement noises. The yaw rate signal is smoother and the computational time is reduced by half under the proposed AMPC scheme in comparison to that under conventional dynamics-model-based MPC. In the meantime, the vehicle slip angle and the steering wheel angle are reduced, which indicates improved vehicle stability.
In this paper, a robust adaptive sliding mode (ASM) controller for improving vehicle maneuverability and lateral stability of steer-by-wire (SBW) vehicles. The proposed stability control algorithm is ...composed of the following three remarkable characteristics: 1) As the vehicle sideslip angle which is very useful in vehicle stability control is often unavailable or unmeasurable for practical applications, a sliding mode-based state observer is proposed to online estimate the actual sideslip angle via the yaw rate and the lateral acceleration measurements. 2) ASM lateral stability controller, as an upper level controller, is designed to calculate the corrected steering angle for driving both the yaw rate and the sideslip angle to achieve their desired values in the presence of modelling uncertainties and external disturbances. Moreover, an adaptive law is incorporated in the control law to estimate the switching gain such that the complex uncertainty bound information can be avoided. 3) The desired steering angle is realized by a lower steering controller via ASM for an SBW system. The hardware-in-the-loop simulation results demonstrate the excellent stability control performance of the proposed control for different steering maneuvers.
With the ongoing promotion and adoption of electric vehicles, intelligent and connected technologies have been continuously advancing. Electrical control systems implemented in electric vehicles have ...emerged as a critical research direction. Various drive-by-wire chassis systems, including drive-by-wire driving and braking systems and steer-by-wire systems, are extensively employed in vehicles. Concurrently, unavoidable issues such as conflicting control system objectives and execution system interference emerge, positioning integrated chassis control as an effective solution to these challenges. This paper proposes a model predictive control-based longitudinal dynamics integrated chassis control system for pure electric commercial vehicles equipped with electro–mechanical brake (EMB) systems, centralized drive, and distributed braking. This system integrates acceleration slip regulation (ASR), a braking force distribution system, an anti-lock braking system (ABS), and a direct yaw moment control system (DYC). This paper first analyzes and models the key components of the vehicle. Then, based on model predictive control (MPC), it develops a controller model for integrated stability with double-layer torque distribution. The required driving and braking torque for each wheel are calculated according to the actual and desired motion states of the vehicle and applied to the corresponding actuators. Finally, the effectiveness of this strategy is verified through simulation results from Matlab/Simulink. The simulation shows that the braking deceleration of the braking condition is increased by 32% on average, and the braking distance is reduced by 15%. The driving condition can enter the smooth driving faster, and the time is reduced by 1.5 s~5 s. The lateral stability parameters are also very much improved compared with the uncontrolled vehicles.
Stability/Control Augmentation System (S/CAS) is widely recognized as a basic framework of flight controllers, and its usefulness has been well established. In general, SAS is composed of a ...proportional controller using attitude rate signals, and CAS is composed of a proportional-integral controller using the errors between attitude/attitude rate/acceleration commands and their current values; that is, S/CAS is a kind of a PID controller with the input signal to the derivative controller being set as the attitude rate signals. The interpretation of PID gains, i.e. appropriateness of PID gains, is very easy since PID gains are directly related to their control actions. On the other hand, due to this too much simplified structure, it is hard to implement another function to PID controllers. In this paper, we propose a novel S/CAS which has the ability to estimate some of plant states in addition to the original control function of improving the stability and the controllability, and we also propose its design method in terms of tractable LMI conditions.
Variable time delays exist between the driver's inputs and the responses of the vehicle dynamic states during a critical steering course. And due to the delay of active brake actuators, a sideslip or ...a rollover may occur even to a vehicle with a traditional stability control system. In addition, the unnecessary intervention of rollover prevention controller may deteriorate yaw stability of a vehicle in these situations. To mitigate the adverse effect of time delay on vehicle stability control and to realize coordinated stability control, a novel three-dimensional dynamic stability controller (3DDSC) is designed for yaw stability control, yaw-roll stability control and rollover prevention control. The framework consists of a supervisor, an upper controller, and a lower controller. A nonlinear vehicle model is used in the supervisor to predict the vehicle's future states and to determine the control mode and the related controllable areas with active brake method. Then model predictive control is used in the upper controller to calculate the desired tire forces of four wheels under the constraints of the given controllable area; then, the desired tire forces are realized by a lower hydraulic pressure controller. The proposed 3DDSC is evaluated with a CarSim-MATLAB cosimulation and hardware-in-the-loop simulation. The results show that 3DDSC can achieve a seamless integration of lateral stability and rollover prevention in complicated steering maneuvers.
This paper considers the problem of collision avoidance for road vehicles, operating at the limits of friction. A two-level modelling and control methodology is proposed, with the upper level using a ...friction-limited particle model for motion planning, and the lower level using a nonlinear 3DOF model for optimal control allocation. Motion planning adopts a two-phase approach: the first phase is to avoid the obstacle, the second is to recover lane keeping with minimal additional lateral deviation. This methodology differs from the more standard approach of path-planning/path-following, as there is no explicit path reference used; the control reference is a target acceleration vector which simultaneously induces changes in direction and speed. The lower level control distributes vehicle targets to the brake and steer actuators via a new and efficient method, the Modified Hamiltonian Algorithm (MHA). MHA balances CG acceleration targets with yaw moment tracking to preserve lateral stability. A nonlinear 7DOF two-track vehicle model confirms the overall validity of this novel methodology for collision avoidance.
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