scholarly journals Applied Mechatronics: Designing a Sliding Mode Controller for Active Suspension System

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Aydin Azizi ◽  
Hamed Mobki

The suspension system is referred to as the set of springs, shock absorbers, and linkages that connect the car to the wheel system. The main purpose of the suspension system is to provide comfort for the passengers, which is created by reducing the effects of road bumpiness. It is worth noting that reducing the effects of such vibrations also diminishes the noise and undesirable sound as well as the effects of fatigue on mechanical parts of the vehicle. Due to the importance of the abovementioned issues, the objective of this article is to reduce such vibrations on the car by implementing an active control method on the suspension system. For this purpose, a conventional first-order sliding mode controller has been designed for stochastic control of the quarter-car model. It is noteworthy that this controller has a significant ability to overcome the stochastic effects, uncertainty, and deal with nonlinear factors. To design a controller, the governing dynamical equation of the quarter-car system has been presented by considering the nonlinear terms in the springs and shock absorber, as well as taking into account the uncertainty factors in the system and the actuator. The design process of the sliding mode controller has been presented and its stability has been investigated in terms of the Lyapunov stability. In the current research, road surface variations are considered as Gaussian white noise. The dynamical system behavior for controlled and uncontrolled situations has been simulated and the extracted results have been presented. Besides, the effects of existing uncertainty in the suspension system and actuator have been evaluated and controller robustness has been checked. Also, the obtained quantitative and qualitative compressions have been presented. Moreover, the effect of controller parameters on the basin of attraction set and its extensiveness has been assessed. The achieved results have indicated the good performance and significant robustness of the designed controller to stabilize the suspension system and mitigate the effects of road bumpiness in the presence of uncertainty and noise factors.

2011 ◽  
Vol 216 ◽  
pp. 96-100
Author(s):  
Jing Jun Zhang ◽  
Wei Sha Han ◽  
Li Ya Cao ◽  
Rui Zhen Gao

A sliding mode controller for semi-active suspension system of a quarter car is designed with sliding model varying structure control method. This controller chooses Skyhook as a reference model, and to force the tracking error dynamics between the reference model and the plant in an asymptotically stable sliding mode. An equal near rate is used to improve the dynamic quality of sliding mode motion. Simulation result shows that the stability of performance of the sliding-mode controller can effectively improve the driving smoothness and safety.


2020 ◽  
Vol 10 (12) ◽  
pp. 4320 ◽  
Author(s):  
Dou Guowei ◽  
Yu Wenhao ◽  
Li Zhongxing ◽  
Amir Khajepour ◽  
Tan Senqi

This paper presents a control method based the lateral interconnected air suspension system, in order to improve the road handling of vehicles. A seven-DOF (Degree of freedom) full-vehicle model has been developed, which considers the features of the interconnected air suspension system, for example, the modeling of the interconnected pipelines and valves by considering the throttling and hysteresis effects. On the basis of the well-developed model, a sliding mode controller has been designed, with a focus on constraining and minimizing the roll motion of the sprung mass caused by the road excitations or lateral acceleration of the vehicle. Moreover, reasonable road excitations have been generated for the simulation based on the coherence of right and left parts of the road. Afterwards, different simulations have been done by applying both bumpy and random road excitations with different levels of roughness and varying vehicle lateral accelerations. The simulation results indicate that the interconnected air suspension without control can improve the ride comfort, but worsen the road handling performance in many cases. However, by applying the proposed sliding mode controller, the road handling of the sprung mass can be improved by 20% to 85% compared with the interconnected or non-interconnected mode at a little cost of comfort.


Author(s):  
C Kim ◽  
P I Ro

In this paper, the control of an active suspension system using a quarter car model has been investigated. Due to the presence of non-linearities such as a hardening spring, a quadratic damping force and the ‘tyre lift-off’ phenomenon in a real suspension system, it is very difficult to achieve desired performance using linear control techniques. To ensure robustness for a wide range of operating conditions, a sliding mode controller has been designed and compared with an existing nonlinear adaptive control scheme in the literature. The sliding mode scheme utilizes a variant of a sky-hook damper system as a reference model which does not require real-time measurement of road input. The robustness of the scheme is investigated through computer simulation, and the efficacy of the scheme is shown both in time and frequency domains. In particular, when the vertical load to the sprung mass is changed, the sliding mode control resumes normal operation faster than the nonlinear self-tuning control and the passive system by factors of 3 and 6, respectively, and suspension deflection is kept to a minimum. Other results showed advantages of the sliding mode control scheme in a quarter car system with realistic non-linearities.


Author(s):  
S. Rajendiran ◽  
P. Lakshmi ◽  
B. Rajkumar

Vehicle vibration can be controlled by Active Suspension System (ASS). The performances of ASS are better than the conventional Passive Suspension System (PSS). The effectiveness of ASS is based on the type of controllers used. In this paper, a quarter car model with ASS is considered for analysis. To reduce the vibration and improve the ride quality, Fractional order Fuzzy Sliding Mode Controller (FrFSMC) is proposed and its performances are compared with Fuzzy Sliding Mode Controller (FSMC) and passive system. While testing the performance of the controllers three types of road disturbances are given to the quarter car model to stimulate the vibration. The results of the proposed controllers are also compared against the existing Gray Fuzzy Sliding Mode Controller (GFSMC). From the time responses and root mean square indices, FrFSMC performs better than the FSMC, GFSMC and PSS.


2020 ◽  
pp. 107754632098244
Author(s):  
Hamid Razmjooei ◽  
Mohammad Hossein Shafiei ◽  
Elahe Abdi ◽  
Chenguang Yang

In this article, an innovative technique to design a robust finite-time state feedback controller for a class of uncertain robotic manipulators is proposed. This controller aims to converge the state variables of the system to a small bound around the origin in a finite time. The main innovation of this article is transforming the model of an uncertain robotic manipulator into a new time-varying form to achieve the finite-time boundedness criteria using asymptotic stability methods. First, based on prior knowledge about the upper bound of uncertainties and disturbances, an innovative finite-time sliding mode controller is designed. Then, the innovative finite-time sliding mode controller is developed for finite-time tracking of time-varying reference signals by the outputs of the system. Finally, the efficiency of the proposed control laws is illustrated for serial robotic manipulators with any number of links through numerical simulations, and it is compared with the nonsingular terminal sliding mode control method as one of the most powerful finite-time techniques.


Author(s):  
Gurubasavaraju Tharehalli mata ◽  
Vijay Mokenapalli ◽  
Hemanth Krishna

This study assesses the dynamic performance of the semi-active quarter car vehicle under random road conditions through a new approach. The monotube MR damper is modelled using non-parametric method based on the dynamic characteristics obtained from the experiments. This model is used as the variable damper in a semi-active suspension. In order to control the vibration caused under random road excitation, an optimal sliding mode controller (SMC) is utilised. Particle swarm optimisation (PSO) is coupled to identify the parameters of the SMC. Three optimal criteria are used for determining the best sliding mode controller parameters which are later used in estimating the ride comfort and road handling of a semi-active suspension system. A comparison between the SMC, Skyhook, Ground hook and PID controller suggests that the optimal parameters with SMC have better controllability than the PID controller. SMC has also provided better controllability than the PID controller at higher road roughness.


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