Control Design for Cancellation of Unnatural Reaction Torque and Vibrations in Variable-Gear-Ratio Steering System

Author(s):  
Atsushi Oshima ◽  
Xu Chen ◽  
Sumio Sugita ◽  
Masayoshi Tomizuka

Variable-gear-ratio steering is an advanced feature in automotive vehicles. As the name suggest, it changes the steering gear ratio depending on the speed of the vehicle. This feature can simplify steering for the driver, which leads to various advantages, such as improved vehicle comfort, stability, and safety. One serious problem, however, is that the variable-gear-ratio system generates unnatural torque to the driver whenever the variable-gear-ratio control is activated. Such unnatural torque includes both low-frequency and steering-speed-dependent components. This paper proposes a control method to cancel this unnatural torque. We address the problem by using a tire sensor and a set of feedback and feedforward algorithms. Effectiveness of the proposed method is experimentally verified using a hardware-in-the-loop experimental setup. Stability and robustness under model uncertainties are evaluated.

Author(s):  
Sumio Sugita ◽  
Masayoshi Tomizuka

Variable-gear-ratio steering, also known as active steering, is an advanced steering technology which enhances the driver’s comfort and vehicle operability. However, one big problem, namely the unnatural reaction torque created by the variable actuator, restricts the further practical-use of the variable-gear-ratio steering. This paper proposes a control method to cancel the unnatural torque using a simple concept called friction relocation. Effectiveness of the method is experimentally confirmed using a hardware-in-the-loop simulator.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jian Wang ◽  
Shifu Liu ◽  
Jian Wu ◽  
Jun Yang ◽  
Aijuan Li

With the rapid development of the vehicle chassis control and autonomous driving technology, it is more and more urgent to realize the active steering technology of autonomous driving stability control. Under emergency conditions, the adhesion constraints, the model uncertainty, and the strong nonlinearity of vehicle bring great challenges to active steering control. In this paper, a model predictive control method for an active steering system based on a nonlinear vehicle model is proposed to solve the problems of adhesion constraint, model uncertainty, and external disturbance in the active steering system. Based on the real-time measurement of vehicle state, a new optimization method is proposed in this paper, which has good performance in dealing with the uncertainty and nonlinearity of the model. The control method transforms the constraint problem into quadratic programming and nonlinear programming. In order to ensure the control accuracy when the vehicle enters the nonlinear area, the control model is built with the combination of the nonlinear tire model and the 2DOF model. The control model is built based on Simulink, and the effectiveness of the controller is the verified joint simulation of Simulink and CarSim. The hardware-in-the-loop (HIL) test bench based on LabVIEW RT is built and tested in order to verify the feasibility and real effect of the controller. Simulation and HIL test results demonstrate that, compared with PID controller, the model predictive controller can accomplish the driving task well and improve the vehicle handling stability.


Author(s):  
M. Selçuk Arslan ◽  
Naoto Fukushima

A Steer-By-Wire (SBW) control scheme is proposed for enhancing the lateral stability and handling capability of a super lightweight vehicle by using the energy optimal control method. Tire dissipation power and virtual power, which is the product of yaw moment and the deviation of actual yaw rate from the target yaw rate, were selected as performance measures to be minimized. The SBW control scheme was tested using Hardware-In-the-Loop (HIL) simulation on an SBW test rig. The case studies performed were high-speed rapid lane change, crosswind, and braking-in-a-turn. HIL simulation results showed that the SBW control scheme was able to maintain vehicle stability. The proposed SBW control design taking advantage of the full range steering of front wheel, significantly improves the vehicle handling capability. The results also demonstrate the importance of SBW control for super lightweight vehicles.


2014 ◽  
Vol 568-570 ◽  
pp. 1031-1035
Author(s):  
Ju Tian ◽  
Yao Chen

The electro-hydraulic load simulator is an important equipment for aircraft hardware-in-the-loop simulation. An adaptive PID control method for compensating extraneous torque with simple structure and easy to implement is proposed according to the variation characteristics of load gradient in the load simulator. The control parameter tuning method is also given.


Author(s):  
Amirhossein Salimi ◽  
Amin Ramezanifar ◽  
Javad Mohammadpour ◽  
Karolos M. Grogoriadis

Restricted space inside the magnetic resonance imaging (MRI) scanner bore prevents surgeons to directly interact with the patient during MRI-guided procedures. This motivates the development of a robotic system that can act as an interface during those interventions. In this paper, we present a master-slave robotic system as a solution to the aforedescribed issue. The proposed system consists of a commercial PHANTOM device (product of The Sensable Technologies) as the master robot and an MRI-compatible patient-mounted parallel platform (that we name ROBOCATH) designed to serve as the slave mechanism inside the scanner bore. We present in this paper the design principles for the platform, as well as the PID control design for the system. We use our experimental setup to evaluate the performance of the system by examining the effectiveness of the slave platform in tracking the reference trajectories generated by the master robot.


2021 ◽  
Author(s):  
Yujian Ren ◽  
Jingxiang Li ◽  
Yuanzhe Dong ◽  
Dong Jin ◽  
Shengdun Zhao

Abstract High efficiency and good section quality are two main objectives of metal bar cropping. A suitable control method can help to achieve both goals. An investigation of the control method of low-cycle fatigue cropping (LCFC) based on the acoustic emission (AE) technique has been proposed in this study. Ring-down counts and kurtosis are used to monitor the whole process of LCFC. The results showed that kurtosis is more suitable for monitoring the LCFC process and as a critical parameter to optimize the control method than ring-down counts in the noisy factory environment.Moreover, three types of materials are studied in this experiment; by combine with the AE results, macroscopic images and microscopic images of sections, characteristics of various LCFC stages are obtained. The results also indicated reduce the area of the transient fracture zone is the key to improve the section quality. Reducing the load frequency before the unstable crack propagation stage will beneficial to realize the goals. Based on the evaluation of kurtosis, an optimized control method is presented, and two control parameters: transient time T and the critical value of the slope of kurtosis C are determined. For 16Mn, 1045 and Al 6061, the T is 5s, 10s, and 1s, respectively. For 16Mn, 1045, and Al 6061, the C is 100, 300, and 0, respectively. Two parameters, h and S, are used to evaluate the section quality and four control strategies are compared. The results indicate the optimal control methods can improve the section quality effectively. The influence trend of reducing loading frequency is investigated by further comparison. It can be seen as the frequency decreases, the efficiency of the section quality improving decreases. In order to realize the optimal results, different control strategies are adopted for different materials. Strategy 1 (high frequency is 20Hz,high frequency thought the whole process), strategy 2 (high frequency is 20Hz,low frequency is 8.33Hz), and strategy 3 (high frequency is 20Hz,low frequency is 6.67Hz) is suitable for Al 6061, 1045, and 16Mn, respectively.


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