摘要 :
The previous paper described the logic tuning, the vehicle manufacture and the evaluation in the HILS system for the purpose of the development of a Steer-By-Wire (SBW) system. This paper describes the content of applying to a new...
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The previous paper described the logic tuning, the vehicle manufacture and the evaluation in the HILS system for the purpose of the development of a Steer-By-Wire (SBW) system. This paper describes the content of applying to a new HILS system, the vehicle manufacture and the result of the evaluation performed in Independent-type SBW (I-SBW) system. Here, the SBW indicates the method of steering both tires by using one motor as the steering gear actuator, similar to the conventional steering system. On the other hand, the I-SBW means the method of steering both front tires independently by using dual motors as the steering gear actuator. As a result, the layout and the kinematical mechanism of the I-SBW system are quite different from those of the typical steering mechanism. Nevertheless, there is no change in the steering column motor system. In the report, we first describe the structure and control logic of the I-SBW system, and then the control effect on this system as applied for both the HILS system and a vehicle. Furthermore, our HILS system involves the actuator mechanism which realizes the reaction force of the road surface with a minimized frictional force in operation. Therefore, it is possible for us to tune the control logic via the HILS system and confirm the effect of the tuned control logic by applying it to a vehicle with the I-SBW system.
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X-by-wire control systems in automotive applications refer to systems where the input device used by the operator is connected to the actuation power subsystem by electrical wires, as opposed to being connected by mechanical or hy...
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X-by-wire control systems in automotive applications refer to systems where the input device used by the operator is connected to the actuation power subsystem by electrical wires, as opposed to being connected by mechanical or hydraulic means. The "X" in the X-by-wire is replaced by "steer," "throttle," and "brake" to represent the steer-by-wire, throttle-by-wire, and brake-by-wire systems. Common to all of these subsystems is that the operator control input device (i.e., steering column, acceleration pedal, and brake pedal) is not connected to the actuation devices mechanically. Rather, it is connected to an embedded computer which, in turn, sends the control signals to the actuation devices. Current state of art steering systems used in articulated vehicles are hydro-mechanical type systems, i.e., the steering column motion is transmitted and amplified by the main hydraulic circuit by hydro-mechanical means. This paper presents a new steer-by-wire (SBW) system which we designed, modeled, analyzed, and tested on wheel type loader construction equipment. The simulation results and tests conducted on a prototype development vehicle (a medium size wheel type loader) show very good agreement. The control algorithm is modeled using graphical modeling tools similar to Simulink and StateFlow. A real-time control algorithm is implemented on a Motorola 68332 microprocessor-based embedded controller. The operational performance of the steer-by-wire system has been convincingly demonstrated.
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While full automation of road vehicles remains a future goal, shared-control and semiautonomous driving-involving transitions of control between the human and the machine-are more feasible objectives in the near term. These altern...
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While full automation of road vehicles remains a future goal, shared-control and semiautonomous driving-involving transitions of control between the human and the machine-are more feasible objectives in the near term. These alternative driving modes will benefit from new research toward novel steering control devices, more suitably where machine intelligence only partially controls the vehicle. In this article, it is proposed that when the human shares the control of a vehicle with an autonomous or semiautonomous system, a force control, or nondisplacement steering wheel (i.e., a steering wheel which does not rotate but detects the applied torque by the human driver) can be advantageous under certain schemes: tight rein or loose rein modes according to the H-metaphor. We support this proposition with the first experiments to the best of our knowledge, in which human participants drove in a simulated road scene with a force control steering wheel (FCSW). The experiments exhibited that humans can adapt promptly to force control steering and are able to control the vehicle smoothly. Different transfer functions are tested, which translate the applied torque at the FCSW to the steering angle at the wheels of the vehicle; it is shown that fractional order transfer functions increment steering stability and control accuracy when using a force control device. The transition of control experiments is also performed with both: a conventional and an FCSW. This prototypical steering system can be realized via steer-by-wire controls, which are already incorporated in commercially available vehicles.
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In this paper, the modeling of steer-by-wire (SbW) systems is further studied, and a sliding mode control scheme for the SbW systems with uncertain dynamics is developed. It is shown that an SbW system, from the steering motor to ...
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In this paper, the modeling of steer-by-wire (SbW) systems is further studied, and a sliding mode control scheme for the SbW systems with uncertain dynamics is developed. It is shown that an SbW system, from the steering motor to the steered front wheels, is equivalent to a second-order system. A sliding mode controller can then be designed based on the bound information of uncertain system parameters, uncertain self-aligning torque, and uncertain torque pulsation disturbances, in the sense that not only the strong robustness with respect to large and nonlinear system uncertainties can be obtained but also the front-wheel steering angle can converge to the handwheel reference angle asymptotically. Both the simulation and experimental results are presented in support of the excellent performance and effectiveness of the proposed scheme.
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In this paper, a robust sliding mode learning control (SMLC) scheme is developed for steer-by-wire (SbW) systems. It is shown that an SbW system with uncertain system parameters and unknown external disturbance from the interactio...
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In this paper, a robust sliding mode learning control (SMLC) scheme is developed for steer-by-wire (SbW) systems. It is shown that an SbW system with uncertain system parameters and unknown external disturbance from the interactions between the tires and the variable road surface can be modeled as a second-order system. A sliding mode learning controller can then be designed to drive both the sliding variable and the tracking error between the steered front-wheel angle and the hand-wheel reference angle to asymptotically converge to zero. The proposed SMLC scheme exhibits many advantages over the existing schemes, including: 1) no information about vehicle parameter uncertainties and self-aligning torque variations is required for controller design; and 2) the control algorithm is capable of efficiently adjusting the closed-loop response based on the most recent history of the closed-loop stability and ensuring a robust steering performance. Both simulations and experiments are presented to show the excellent steering performance and the effectiveness of the proposed learning control methodology.
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A robust yaw stability control design based on active front steering control is proposed for in-wheel-motored electric vehicles with a Steer-by-Wire (SbW) system. The proposed control system consists of an inner-loop controller (r...
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A robust yaw stability control design based on active front steering control is proposed for in-wheel-motored electric vehicles with a Steer-by-Wire (SbW) system. The proposed control system consists of an inner-loop controller (referred to in this paper as the steering angle-disturbance observer (SA-DOB), which rejects an input steering disturbance by feeding a compensation steering angle) and an outer-loop tracking controller (i.e., a PI-type tracking controller) to achieve control performance and stability. Because the model uncertainties, which include unmodeled high frequency dynamics and parameter variations, occur in a wide range of driving situations, a robust control design method is applied to the control system to simultaneously guarantee robust stability and robust performance of the control system. The proposed control algorithm was implemented in a CaSim model, which was designed to describe actual in-wheel-motored electric vehicles. The control performances of the proposed yaw stability control system are verified through computer simulations and experimental results using an experimental electric vehicle.
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This paper proposes a novel adaptive hierarchical control approach for Steer-by-Wire (SbW) vehicles to improve the handling stability. The high-level stability control scheme contains a variable steering ratio (VSR) strategy based...
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This paper proposes a novel adaptive hierarchical control approach for Steer-by-Wire (SbW) vehicles to improve the handling stability. The high-level stability control scheme contains a variable steering ratio (VSR) strategy based on the adaptive-network-based fuzzy inference system (ANFIS) and an active front steering (AFS) controller designed with the integral sliding mode method by tracking the expected yaw rate, in which the desired front wheel angle is generated to enhance the cornering stability performance. Besides, an adaptive tracking controller (ATC) for the SbW system is designed by using the adaptive sliding mode control method to achieve desired steering performance in the lower level. The proposed adaptive control strategy is validated with different driving circles from ISO standards in simulation tests and hardware-in-the-loop (HiL) experiments. The results demonstrate that the designed control approach improve the vehicle handling stability significantly, even in some extreme driving conditions.
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This paper presents a novel adaptive fuzzy sliding mode (AFSM) control scheme for a vehicle steer-by-wire (SbW) system. Initially, the dynamics of the SbW system are described by a second-order differential equation where the Coul...
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This paper presents a novel adaptive fuzzy sliding mode (AFSM) control scheme for a vehicle steer-by-wire (SbW) system. Initially, the dynamics of the SbW system are described by a second-order differential equation where the Coulomb friction and the self-aligning torque are treated as external disturbances. Furthermore, an AFSM controller is designed for the SbW system, which utilizes an adaptive law to estimate both the Coulomb friction and the self-aligning torque, a sliding mode control component to deal with the parametric uncertainties and unmodeled dynamics, and a fuzzy strategy to strike a good balance between the chattering-alleviation and the tracking precision. The stability of the control system is verified in the sense of Lyapunov, and the selection of control parameters is provided in detail. Lastly, experiments are carried out under various road conditions. The experimental results demonstrate that the developed AFSM controller possesses superiority in terms of higher tracking accuracy, stronger robustness and a better balance between the control precision and smoothness in comparison with a conventional sliding mode (CSM) controller and a boundary layer-based adaptive sliding mode (BLASM) controller.
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This paper proposes a novel adaptive terminal sliding-mode (ATSM) control scheme for a Steer-by-Wire (SBW) vehicle. It is shown that the developed ATSM controller can drive the closed-loop error dynamics to converge to zero in a f...
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This paper proposes a novel adaptive terminal sliding-mode (ATSM) control scheme for a Steer-by-Wire (SBW) vehicle. It is shown that the developed ATSM controller can drive the closed-loop error dynamics to converge to zero in a finite time, where adaptive laws are applied to estimate the uncertain bounds of the system parameters and disturbances in Lyapunov sense. Compared with the sliding-mode-based SBW control systems, the proposed ATSM control not only assures the finite-time error convergence and strong robustness with respect to parameter uncertainties and varying driving conditions, but also requires no prior knowledge of the system parameters and road information. Experimental results from an SBW vehicle are demonstrated to verify the remarkable performance of the proposed control in terms of the robustness, error convergence, and road disturbance attenuation, in comparison with other control strategies.
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This article proposes an individual auxiliary and fault-tolerant control (IAFTC) for the electric vehicles with the steer-by-wire system considering different drivers steering characteristics. It is composed of an individual auxil...
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This article proposes an individual auxiliary and fault-tolerant control (IAFTC) for the electric vehicles with the steer-by-wire system considering different drivers steering characteristics. It is composed of an individual auxiliary controller, a fault detection and diagnosis controller (FDDC), and an individual fault-tolerant controller. The individual auxiliary controller is used to specifically assist the drivers' steering behaviors and maintain their steering style when the steering motors are healthy. The FDDC detects and estimates the state and parameter of actuators in real time as well as feedbacks the condition or the extent of partial damage concerning motors to ECU. After the fault-tolerant command is transmitted from ECU, an individual fault-tolerant controller will be turned ON to deal with the influence of faulty motor on different drivers. The IAFTC strategy can specifically assist the drivers to track the reference path, reducing the physical and mental workloads of drivers in the no-fault or fault vehicle steering process. The results of simulation using the Matlab and hardware-in-the-loop tests indicate that the controller can provide appropriate assistance control to different drivers in a human-vehicle cooperative method so as to deal with complex actuator's condition.
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