An integrated control of front in-wheel motors and rear electronic limited slip differential for high-speed cornering performance

Author(s):  
Hyunsoo Cha ◽  
Youngjin Hyun ◽  
Kyongsu Yi ◽  
Jaeyong Park

This paper presents an integrated control of in-wheel motor (IWM) and electronic limited slip differential (eLSD) for high-speed cornering performance. The proposed algorithm is designed to improve the handling performance near the limits of handling. The proposed controller consists of a supervisor, upper-level controller, and lower-level controller. First, the supervisor determines a target motion based on the yaw rate reference with a target understeer gradient. The target understeer gradient is devised to improve the lateral stability with in-wheel motor control based on a nonlinear static map. The yaw rate reference is designed based on the target understeer gradient to track the yaw reference with eLSD control. Second, the upper-level controller calculates the desired yaw moments for IWM and eLSD to generate the target motion. Third, the lower-level controller converts the desired yaw moment to the actuator torque commands for IWMs and eLSD. The tire friction limits are estimated based on the tire model and friction circle model to prevent tire saturation by limiting the torque inputs. The proposed algorithm has been investigated via both simulations and vehicle tests. The performance of the integrated control was compared with those of individual control and uncontrolled case in the simulation study. The vehicle tests have been performed using a rear wheel drive vehicle equipped with two front IWMs and eLSD in the rear axle. The vehicle test has been conducted at a racing track to show that the proposed algorithm can improve the lateral stability near the limits of handling.

Author(s):  
Mark W. Arndt ◽  
Stephen M. Arndt

The effects of reduced kingpin offset distance at the ground (scrub radius) and speed were evaluated under controlled test conditions simulating front tire tread detachment drag. While driving in a straight line at target speeds of 50, 60, or 70 mph with the steering wheel locked, the drag of a tire tread detachment was simulated by applying the left front brake with a pneumatic actuator. The test vehicle was a 2001 dual rear wheel four-wheel-drive Ford F350 pickup truck with an 11,500 lb. GVWR. The scrub radius was tested at the OEM distance of 125 mm (Δ = 0) and at reduced distances of 49 mm (Δ = −76) and 11 mm (Δ = −114). The average steady state responses at 70 mph with the OEM scrub radius were: steering torque = −24.5 in-lb; slip angle = −3.8 deg; lateral acceleration = −0.47 g; yaw rate = −8.9 deg/sec; lateral displacement after 0.75 seconds = 3.1 ft and lateral displacement after 1.5 seconds = 13.1 ft. At the OEM scrub radius, responses that increased linearly with speed included: slip angle (R2 = 0.84); lateral acceleration (R2 = 0.93); yaw rate (R2 = 0.73) and lateral displacement (R2 = 0.59 and R2 = 0.87, respectively). At the OEM scrub radius, steer torque decreased linearly with speed (R2 = 0.76) and longitudinal acceleration had no linear relationship with speed (R2 = 0.09). At 60 mph and 70 mph for both scrub radius reductions, statistically significant decreases (CI ≥ 95%) occurred in average responses of steer torque, slip angle, lateral acceleration, yaw rate, and lateral displacement. At 50 mph, reducing the OEM scrub radius to 11 mm resulted in statistically significant decreases (CI ≥ 95%) in average responses of steer torque, lateral acceleration, yaw rate and lateral displacement. At 50 mph the average slip angle response decreased (CI = 87%) when the OEM scrub radius was reduced to 11 mm.


2010 ◽  
Vol 118-120 ◽  
pp. 728-732
Author(s):  
Shu Wen Zhou ◽  
Si Qi Zhang ◽  
Guang Yao Zhao

Tractor semitrailers on high speed obstacle avoidance under emergency are likely to arise rollover or jack-knifing, which are serious risks for motorists. A dynamic stability analysis model of a three-axle tractor semitrailer vehicle is developed using the application tool. The linearized vehicle model is utilized to predict the dynamics state of the tractor semitrailer built in multibody dynamics simulation software. The lateral stability simulation for yaw rate following and anti-rollover has been performed on the dynamic model based on virtual prototyping. The results show that the lateral stability control based on tractor semitrailer proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing can be prevented to a large extent.


2010 ◽  
Vol 29-32 ◽  
pp. 1420-1424
Author(s):  
Shu Wen Zhou ◽  
Si Qi Zhang ◽  
Guang Yao Zhao

Since the handling behaviour of car-trailer combination is more complex and less predictable than that of non-articulated vehicles, the drivers may lose control of the vehicle in some hasty steering maneuvers. The kinematics of car-trailer combination has been analyzed with a 3 DOF model. A modified Vehicle Dynamics Control system was designed to improve the lateral stability of the trailer. The dynamics simulation for lateral stability of car-trailer combination has been performed on the multi-body model. The results show that the lateral stability of car-trailer combination, including yaw rate and roll angle has been improved with the modified Vehicle Dynamics Control system.


Author(s):  
Rami Y. Hindiyeh ◽  
J. Christian Gerdes

This paper presents a controller framework for autonomous drifting of a rear wheel drive vehicle. The controller uses a successive loop structure, where yaw rate is treated as a synthetic input to control the vehicle’s sideslip dynamics, and yaw rate is in turn controlled through coordination of steering and rear drive force. Relative to prior designs, the drift controller presented in this work enables a straightforward, physically insightful stability analysis where local closed-loop stability of the desired high sideslip “drift equilibrium” is demonstrated. When implemented on a by-wire testbed, the new controller achieves experimental performance that matches or exceeds prior designs, generating sustained and robust autonomous drifts.


Author(s):  
Milad Jalali ◽  
Amir Khajepour ◽  
Shih-ken Chen ◽  
Bakhtiar Litkouhi

In this paper, a new approach is proposed to deal with the delay in vehicle stability control using model predictive control (MPC). The vehicle considered here is a rear-wheel drive electric (RWD) vehicle. The yaw rate response of the vehicle is modified by means of torque vectoring so that it tracks the desired yaw rate. Presence of delays in a control loop can severely degrade controller performance and even cause instability. The common approaches for handling delays are often complex in design and tuning or require an increase in the dimensions of the controller. The proposed method is easy to implement and does not entail complex design or tuning process. Moreover, it does not increase the complexity of the controller; therefore, the amount of online computation is not appreciably affected. The effectiveness of the proposed method is verified by means of carsim/simulink simulations as well as experiments with a rear-wheel drive electric sport utility vehicle (SUV). The simulation results indicate that the proposed method can significantly reduce the adverse effect of the delays in the control loop. Experimental tests with the same vehicle also point to the effectiveness of this technique. Although this method is applied to a vehicle stability control, it is not specific to a certain class of problems and can be easily applied to a wide range of model predictive control problems with known delays.


Author(s):  
CS Nanda Kumar ◽  
Shankar C Subramanian

In electric and hybrid vehicles, regenerative braking is applied only at the driven wheels by the electric drive, whereas the non-driven wheels are not subjected to brake force during the pure regenerative braking mode. The application of pure regenerative brake may affect the vehicle’s lateral stability during a turn. The impact could be more severe when the pure regenerative brake is applied at the turn on the rear wheels (for a rear wheel drive vehicle) over a low friction road surface. As part of a solution to reduce this impact, a brake force sharing (BFS) strategy between regenerative and friction brake has been proposed in this paper, which improves the brake force distribution between front and rear wheels to ensure a stable turn. The vehicle model and the BFS strategy were developed, and the IPG Car Maker® software was used to evaluate the effectiveness of the proposed strategy. The simulation results on BFS strategy have been corroborated using experimental data collected from a test vehicle. Further, a closed loop control structure was developed for implementing the proposed BFS strategy in electric and hybrid vehicles.


Author(s):  
Maithili Patel ◽  
Manthan Mahajan

A racing vehicle requires to be designed for optimum performance, stability and maneuverability considering all situations like straight line acceleration and high speed cornering. The car is driven close to its tractive limits and a control system becomes inevitable to manifest utmost performance of the car. In this paper, the focus is on design of an electronic differential for a rear wheel driven Formula Student Electric vehicle, with each rear wheel driven by separate motors. The electronic differential (e-diff) is aimed at both straights and corners, which is fulfilled by considering objective parameters, which assist in cornering by improving yaw rate and straights by improving traction. However, in this paper we shall focus on cornering only. The paper looks at various possible control strategies for obtaining desired values of certain parameters and describes in detail implementation of a yaw rate controlled system. A vehicle model is created on MATLAB/Simulink platform to look at changes in vehicle behavior in response to various control strategies. The model consists of vehicle dynamics and driver models developed by the authors. The coupled model simulates the vehicle performance on any given track and provides the variation of required parameters. Iterations are done and the results are used to tune the controller parameters to optimize performance on tight turns and overall lap times at the endurance event at the Formula Student competition.


Author(s):  
Ildar Gabitov ◽  
Andrei Negovora ◽  
Azamat Valiev ◽  
Vladimir Ilin ◽  
Danila Plotnikov ◽  
...  

This paper presents a method for the vehicle speed estimation with a Fuzzy Logic based algorithm. The algorithm acquires the measurements of the yaw rate, steering angle, wheel velocities and exploits a set of five Fuzzy Logics dedicated to different driving conditions. The technique estimates the speed exploiting a weighted average of the contributions provided by the longitudinal acceleration and the credibility assigned by the Fuzzy Logics to the measurements of the wheels’ speed. The method is experimentally evaluated on an all-wheel drive electric racing vehicle and is valid for the front and rear wheel drive configurations. The experimental validation is performed by comparing the obtained estimation with the result of computing the speed as the average of the linear velocity of the four wheels. A comparison to the integral of the vehicle acceleration over time is reported.


2009 ◽  
Vol 16-19 ◽  
pp. 544-548 ◽  
Author(s):  
Shu Wen Zhou ◽  
Hai Shu Chen ◽  
Si Qi Zhang ◽  
Li Xin Guo

Rollover and jack-knifing of tractor semitrailer on high speed obstacle avoidance under emergency are serious threats for motorists. A tractor semitrailer model was built with multi-rigid-body method in this paper. The steering performance of tractor semitrailer has been analyzed, as well as the stability control theory, including yaw rate following, anti-rollover. The dynamics simulation for yaw rate following and anti-rollover has been performed on the dynamic tractor semitrailer. The results show that the vehicle dynamics control proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing are prevented and the tractor semitrailer more accurately follows the driver's desired path.


Sign in / Sign up

Export Citation Format

Share Document