Suspension Control Research Articles

Semi-active control of primary suspensions to improve ride quality in a high-speed railway vehicle

Semi-active suspensions are seen as a promising technology to improve ride quality in high-speed railway vehicles as they provide substantial benefits not achievable through an optimisation of the passive suspension while avoiding some drawbacks of full-active control. Previous works showed that semi-active primary suspensions (SAPS) offer significant improvement of ride quality. However, published implementations of this concept did not consider the coupling effects between car-body and bogie vibrations, which play a decisive role in the success of control strategies for SAPS. This paper provides a comprehensive analysis of SAPS to improve vehicle ride comfort, with special attention to the mitigation of car-body bending vibration. A vehicle model considering the coupling of car-body bending and bogie pitch is proposed and used for the synthesis of an LQG controller. The performance of the semi-active suspension and controller is assessed using a detailed flexible multibody system of a high-speed vehicle. The proposed control scheme is shown to be highly effective in reducing car-body vibration in the entire frequency range of interest from 1 Hz to20Hz. A remarkable ride comfort improvement is found in the entire speed range from 150 km/h to 350 km/h.

Investigation of Vehicle Stability by Integration of Active Suspension, Torque Vectoring, and Direct Yaw Control

Investigation of Vehicle Stability by Integration of Active Suspension, Torque Vectoring, and Direct Yaw Control

The design of the magnetic suspension control system cargo platform

Background: The paper discusses the features of building a control system for an electro-magnetic suspension of a cargo platform. The operating conditions of cargo systems are associated with a large range of changes in the mass of the cargo and an abrupt change in the voltage of the power source. The control structure of the electromagnetic suspension system contains a non-linear unstable object (electromagnet). This greatly complicates the management process.
 Aim: The aim of the work is to study the properties of an unstable control object for its representation by an equivalent linear model, which makes it possible to automate the process of controller synthesis in the MATLAB software environment.
 Methods. The main research methods are computer modeling, computational studies, analysis of research results.
 Results: An approach to the construction of an adaptive control system for an electromagnetic suspension based on the synthesis of a linear controller based on an equivalent linear model of an unstable object is proposed.
 Conclusion: The practical significance lies in the fact that the proposed approach can be used to design a control system for the electromagnetic suspension of a cargo platform.

Two-Terminal Suspension Adaptive Control With Synchronous Compensation for Maglev Wind Turbine Yaw System

The article proposes an adaptive robust controller with synchronization compensation for the Maglev wind turbine yaw system to achieve stable nacelle suspension and pitching suppression. First, two-degree-of-freedom suspension model is constructed with consideration of magnetic coupling and pitching interference, and then deduces a two-terminal suspension control model based on the inverse system. Second, a nominal suspension controller is designed based on the composite error; and then an adaptive synchronization controller is proposed to adjust coupling parameters based on reconstructed synchronous function; an adaptive tracking controller is used to online update dominant control input parameters. The robust controller is to compensate for the influence of the approximation errors during the parameters convergence process. It is proved that the proposed strategy can guarantee the globally uniformly ultimately bounded of all signals, and suspension tracking error and synchronization error can converge to the desired smaller neighborhood of zero. Finally, simulation and experimental results show that the system with the proposed strategy has the faster dynamic response, smaller steady error and synchronization error, and stronger robustness than other two strategies.

Magnetorheological Fluid-Based Bending Actuator for Magnetic Sensing

Magnetorheological (MR) fluids have applications in diverse areas such as automobile suspension, architecture, and vibration control due to their fast response, wide range of controllability, and temperature resistance. However, traditional MR fluids-based applications for robotics lack the capability of sensing that can provide information about the environment. In this letter, we present a MR fluid-based bending actuator for magnetic sensing by integrating a strain gage into the actuator. Its deflection can be detected by reading the change of resistance when the actuator deflects under different external magnetic fields. Subsequently, we obtain the relationship between the magnetic flux density and the deflection by deriving an analytical model. To demonstrate the magnetic actuation capability of the actuator, we fabricate a fish-like robot whose tail is composed of the actuator. We further conduct simulations and experiments to validate the analytical model of magnetic sensing. This model shows good agreement with the simulation and experiment results. We validate the actuator for magnetic sensing by demonstrating that it can exhibit a good tracking response of dynamic signals (maximum absolute error smaller than 2.5 mT). The results illustrate that the MR fluid-based bending actuator has the potential to use in the environmental inspection.

Research on sliding mode controller of the high-speed maglev train under aerodynamic load

The high-speed maglev train will be subjected to extremely obvious aerodynamic load and instantaneous aerodynamic impact during passing another train, which brings significant challenges to the train’s suspension stability and safe operation. It’s necessary to consider the influence of aerodynamic load and shock waves in the design of suspension control algorithms. Traditional proportion integration differentiation (PID) control cannot follow the change of vehicle parameters or external disturbance, which is easy to cause suspension fluctuation and instability. To improve the suspension stability and vibration suppression of the high-speed maglev train under aerodynamic load and impact, we design a siding mode controller introducing the primary suspension’s deformation to replace the aerodynamic load on the electromagnet. Furthermore, we establish the train’s dynamic simulation model with three vehicles and compare the designed controller and the PID controller for their performance in controlling the model suspension stability in the presence of the train operating in open air. Simulation results show that the sliding mode control (SMC) method proposed in this paper can effectively restrain the electromagnet fluctuation of the train under aerodynamic loads.

Real time hardware implementation of discrete sliding mode fuzzy controlled buck converter using digital signal processor

This paper deals with the real time hardware implementation of discrete sliding mode fuzzy control (DSMFC) for buck converter using digital signal processor (DSP). Applications like electric vehicle suspension control, flight dynamic control, robot position control and engine throttle position control; sliding mode control (SMC) plays a major role. Hardware realization is difficult with SMC strategy due to the continuous gain change results in chattering problem and actuator or contact may break. To resolve this problem the fuzzy logic (FL) approach has combined with the robust technique discrete sliding mode control (DSMC) to develop a new strategy for DSMFC. The mathematical modeling of the controller is done using MATLAB/Simulink software and practical design of the converter is also realized. The robustness of the controller is proved by introducing sudden change in input voltage as well as load with the help of switching circuit in hardware realization. The obtained practical results are verified by comparing with the simulation output and reference value.

Cooperative Control of Interconnected Air Suspension Based on Model Predictive Control

The suspension system is a significant part of a vehicle because it transmits the torque and force between the wheels and the frame, meeting the requirements of ride comfort. In this paper, a novel interconnected air suspension was introduced and a cooperative control between interconnected mode activation (IMA) and outsourced mode activation (OMA) was designed. To improve ride comfort in a bus at a minimal energy consumption, this cooperative control based on model predictive control (MPC) for computing the best force and the rule was defined to distribute the best suspension force generated by IMA and OMA. The simulation and experimental results showed that the proposed control strategy significantly improved ride comfort in different conditions. Compared with traditional control in the test vehicle, the RMS of the front-left sprung mass and unsprung vertical acceleration decreased by 24.2% and 14.5%, respectively, under a straight condition; the RMS of the sprung (unsprung) mass vertical acceleration reduced by 22.38% and 15.43%, respectively, under a bump condition.

Development of APP-Controlled Hydraulic Damping Adjustment System for Bike Front Fork

With quickly growing environmental awareness, cycling has become a popular global activity. However, the bike riding road may be so rugged that the suspension damping status should be appropriately adjusted to make riding more comfortable. Traditionally, the damping adjustment in bikes relies on a manual operation in advance, causing inconvenience during riding. To resolve this problem, this paper aims to develop an APP-controlled hydraulic damping adjustment system for bike front fork suspension control. The microprocessor works as a core controller. G-sensor (accelerometer) is used to detect the road condition. Blade with photointerrupter circuit is designed to accurately control the DC motor rotating position for determining fork damping ratio. Moreover, APP can send control signals and receive data to/from the microprocessor via Bluetooth module between each other. Additionally, the bike driving mileage, period of time, and route can be displayed on APP instantly. The experimental results confirm that the proposed system is superior in term of robustness, accuracy, and convenience.

Multi-objective H2/H∞ control of uncertain active suspension systems with interval time-varying delay

The vehicle active suspension has been widely used as it could effectively improve the vehicle ride comfort. To solve the issues of actuator uncertainty and time delay existing in the active suspension system, a multi-objective non-fragile [Formula: see text] control algorithm is proposed in this work. First, to effectively describe the vehicle suspension dynamics, a quarter-car suspension model is constructed first in this study. Second, aiming at improving the ride quality and guarantee the hard constraints of the suspension system, a multi-objective H2/ H∞ performance index is proposed. Subsequently, the issues of external disturbances, actuator uncertainty and delay are considered in the design process of the suspension controller. Then, a multi-objective non-fragile control algorithm is proposed based on an effective Lyapunov functional. The control gain can be obtained by solving a convex optimization problem in terms of linear matrix inequalities. Finally, numerical simulations are implemented on MATLAB/Simulink platform to show the robustness and superiority of the proposed controller. Experiments are implemented on a quarter-car test rig to validate the practical performance of the designed controller.

Research on Control of Semi-Active Suspension System Using Hydraulic Single-Tube Shock Absorber

There are some factors that influence a running vehicle. The dynamic forces acting at the contact between tires and rough road surfaces can have a detrimental impact on passenger health and vehicle safety. The purpose of the automotive suspension system is to reduce the impact of these forces and vibrations on passengers and also improve mobility, safety and the vehicle’s longevity itself. The stiffness of the springs and the damping characteristic of the shock absorbers should be sufficiently non-linear for system's substantial performance. Many studies on the control of vehicle suspension system have lately been conducted in order to increase ride comfort and maneuverability but shock absorber’s model has not been described detailly. This paper proposed a PID controller for a semi-active suspension system with a hydraulic single-tube shock absorber. A quarter-car model with a sub-model of the single-tube shock absorber was used to perform the simulation. In comparison with the non-controlled system, the damping performance of the controlled system increased significantly.

On an enhanced back propagation neural network control of vehicle semi-active suspension with a magnetorheological damper

To improve the ride quality of a vehicle, an enhanced vibration control method is presented for semi-active suspension (SAS) with magnetorheological (MR) damper by combining back propagation neural network (BPNN) and particle swarm optimization (PSO). Based on the test data of MR damper, a non-parametric model of MR damper using adaptive neuro-fuzzy inference system (ANFIS) is first established, and based on that, a dynamics model of the SAS system is derived. Next, a BPNN controller is designed to fulfill the effective control of the current in MR damper. Meanwhile, the improved PSO with adaptive weight and dynamic acceleration constant is introduced to optimize the weights and thresholds of the BPNN controller, which can avoid the designed BPNN falling into the local optimum and then improve the convergence rate of the designed controller. Besides, the stability of the developed controller is analyzed via Lyapunov stability theory. Different from the existing models and methods, the established model can well describe the dynamics behaviors of the actual MR damper, and the proposed control method has better adaptability, convergence speed and precision. Finally, a simulative investigation is performed to validate the effectiveness and feasibility of the proposed controller, compared to existing BP-PID control and the passive suspension, the vehicle acceleration of SAS with this proposed controller is respectively improved by 10% and 30%.

Adaptive Control of Two-Pendulum Suspension of Overhead Crane

When constructing the bridge crane control law, a two-pendulum model with a hook suspension, on which the transported load is suspended, and a load suspension is considered. This model more accurately describes the dynamics of cargo movement, which is especially critical in a number of crane operating modes, including cases when the mass-inertial parameters of the cargo are close to the hook. A mathematical model of the two-pendulum mechanical system of the crane suspension along one axis of its movement is described, taking into account the effect of friction forces when moving the crane trolley and wind disturbance acting on the transported cargo. Also, there is presented linearized model of hook movement with control action in the form of preset speed of crane trolley movement. The latter corresponds to the use of a servo motor or stepper motor to control the trolley. On the basis of the obtained linearized model, an adaptive control law is constructed using a scheme including an algorithm for current parametric identification, an implicit reference model, "simplified" adaptability conditions with direct tracking of hook movement (through it — cargo movement) by the properties of the assigned reference model. This control law allows you to build crane control under the current parametric uncertainty of the properties of the crane, the transported cargo and external disturbances (only approximate information about some parameters is assumed). It is shown that in the case when the natural frequency of the assigned reference model is less than that for the hook suspension, the proposed control law generates asymptotic movement of the hook (load) to the assigned point and damping of angular oscillations of the hook suspension and load suspension. For more efficient damping of angular oscillations in case of large values of load moment of inertia, it is proposed to supplement preset value of hook movement with damping movements based on angular movement of load suspension. Model examples supporting theoretical conclusions are given. It is shown that the proposed solution makes it possible to build a bridge crane control under the action of measurement noise and control signal delays.

Design of passive suspension system to mimic fuzzy logic control active suspension system

BackgroundThis paper proposes a method for designing a passive suspension system that determines the optimal suspension settings while offering feasible performance near an active suspension system. A mathematical model of a nonlinear quarter car is developed and simulated for control and optimization in MATLAB/Simulink® environment. The input road condition is a Class C Road, and the vehicle moves at 80 kmph. Fuzzy logic control (FLC) action is used to accomplish active suspension system control. An approach for investigating optimal suspension settings based on the FLC control force is described here. The optimized passive suspension system is supposed to have the same suspension travel and velocity as an active suspension system. The least square technique is implemented to optimize the suspension parameters of the passive suspension system.ResultsThe initial passive suspension system, FLC active system, and optimized suspension system are simulated in MATLAB/Simulink® environment. It is observed that RMS acceleration for the FLC system is 0.5057 m/s2, which is reduced by 46% (passive suspension system has RMS acceleration of 0.9322 m/s2, which is uncomfortable). For optimized system, RMS acceleration is 0.6990 m/s2. It is observed that the optimized passive suspension system almost mimics the initial FLC active suspension system. For the optimized system, sprung mass acceleration and VDV are improved by 30% and 27%, respectively, compared to the initial passive system.ConclusionIt is observed that the optimized passive suspension system mimics the initial FLC system. Also, an optimized FLC system has improved health criterion-based results compared to other suspension systems.

Communication-Constrained Active Suspension Control for Networked In-Wheel Motor-Driven Electric Vehicles With Dynamic Dampers

This paper is concerned with the networked active suspension control problem for in-wheel motor-driven electric vehicles subject to communication constraints, including intermittent data transmissions, quantized output measurements and network-induced transmission delays. The central goal is to develop a resource-efficient communication and active suspension control co-design approach such that the limited in-vehicle network resources are occupied in an efficient manner, while simultaneously achieving the desired suspension system performance. For this purpose, a networked data transmission framework, incorporating a dynamic event-triggered communication mechanism and a logarithmic quantizer, is developed to accommodate the intermittent and digitalized packet-based transmissions over the in-vehicle controller area network channels. Specifically, the event triggering mechanism sporadically selects the sampled sensor data packets to be transmitted, which are then quantized before sending over the network channels. Then, formal stability and suspension performance analysis is carried out, and a co-design criterion on the existence of the desired triggering mechanism and event-triggered output feedback controller is further derived. Finally, the effectiveness and merits of the derived results are substantiated via several numerical case studies.

On Pre-Emptive In-Wheel Motor Control for Reducing the Longitudinal Acceleration Oscillations Caused by Road Irregularities

Road irregularities induce vertical and longitudinal vibrations of the sprung and unsprung masses, which affect vehicle comfort. While the vertical dynamics and related compensation techniques are extensively covered by the suspension control literature, the longitudinal dynamics on uneven road surfaces are less frequently addressed, and are significantly influenced by the tires and suspension systems. The relatively slow response of internal combustion engines does not allow any form of active compensation of the effect of road irregularities. However, in-wheel electric powertrains, in conjunction with pre-emptive control based on the information on the road profile ahead, have some potential for effective compensation, which, however, has not been explored yet. This paper presents a proof-of-concept nonlinear model predictive control (NMPC) implementation based on road preview, which is preliminarily assessed with a simulation model of an all-wheel drive electric vehicle with in-wheel motors, including a realistic tire model for ride comfort simulation. The major improvement brought by the proposed road preview controller is evaluated through objective performance indicators along multiple maneuvers, and is confirmed by the comparison with two benchmarking feedback controllers from the literature.

Research on the Mechanism and Control Characteristics of Vehicle-Track Beam Coupling Vibration for Medium-Speed Maglev Vehicle

In the maglev transportation system, the track beam may vibrate under the dynamic levitation force of the maglev vehicle due to its own elastic characteristics, which may cause the vehicle to vibrate. At present, the general method of suppressing vibration is to improve the stiffness, density, damping of the bridge, and the accuracy of track installation, which will result in higher construction costs. In this article, the simulation analysis of the vehicle-rail coupling vibration is carried out from the perspective of suspension control characteristics. Through theoretical derivation, a mathematical model is established, and the mechanism of the vehicle-bridge coupling system vibration is analyzed through simulation. The internal influence of the main parameters of the controller on the system vibration is discussed. Theoretical analysis and simulation research show that the mismatch between the structural parameters of the track beam and the controller parameters will cause coupled vibration, while adjusting the parameters to match the track beam structure can suppress vibration to a certain extent. Taking the 25-m simply supported beam of Changsha Maglev Express as the research object, the vehicle-bridge coupled vibration characteristics test under 75–140-km/h operating speed is carried out, and the dynamic response of the vehicle and the bridge frame is obtained. Dynamic experiments show that proper controller parameters can maintain a stable suspension of the vehicle. This research provides theoretical and experimental references for vehicle-track coupled vibration suppression and maglev transportation system optimization.

A new active suspension control scheme for vehicles considering steering stability

A new active suspension control scheme for vehicles considering steering stability

On the Resonant Vibrations Control of the Nonlinear Rotor Active Magnetic Bearing Systems

Nonlinear vibration control of the twelve-poles electro-magnetic suspension system was tackled in this study, using a novel control strategy. The introduced control algorithm was a combination of three controllers: the proportional-derivative (PD) controller, the integral resonant controller (IRC), and the positive position feedback (PPF) controller. According to the presented control algorithm, the mathematical model of the controlled twelve-poles rotor was established as a nonlinear four-degree-of-freedom dynamical system coupled to two first-order filters. Then, the derived nonlinear dynamical system was analyzed using perturbation analysis to extract the averaging equations of motion. Based on the extracted averaging equations of motion, the efficiency of different control strategies (i.e., PD, PD+IRC, PD+PPF, and PD+IRC+PPF) for mitigating the rotor’s undesired vibrations and improving its catastrophic bifurcation was investigated. The acquired analytical results demonstrated that both the PD and PD+IRC controllers can force the rotor to respond as a linear system; however, the controlled system may exhibit the maximum oscillation amplitude at the perfect resonance condition. In addition, the obtained results demonstrated that the PD+PPF controller can eliminate the rotor nonlinear oscillation at the perfect resonance, but the system may suffer from high oscillation amplitudes when the resonance condition is lost. Moreover, we report that the combined control algorithm (PD+IRC+PPF) has all the advantages of the individual control algorithms (i.e., PD, PD+IRC, PD+PPF), while avoiding their drawbacks. Finally, the numerical simulations showed that the PD+IRC+PPF controller can eliminate the twelve-poles system vibrations regardless of both the excitation force magnitude and the resonant conditions at a short transient time.

Initial Pitch Control for Semi-active Suspension System

Initial Pitch Control for Semi-active Suspension System