Control of Suspensions for Vehicles With Flexible Bodies—Part I: Active Suspensions

1996 ◽  
Vol 118 (3) ◽  
pp. 508-517 ◽  
Author(s):  
Aleksander Hac´ ◽  
Iljoong Youn ◽  
Hsien H. Chen
Keyword(s):  
Rigid Body ◽  
Output Feedback ◽  
Control Strategies ◽  
The Body ◽  
Vehicle Body ◽  
Structural Vibrations ◽  
Control Laws ◽  
Modal Damping ◽  
Rigid Body Model ◽  
Full State Feedback

In this paper, two classes of control strategies for active suspension are developed. The purpose of control is to reduce structural vibrations of the body without compromising traditional control objectives. In the first approach, the control laws for the suspension forces are synthesized to enhance modal damping in the structural modes. In the second approach, a separate proof-mass actuator mounted on the vehicle body is used to suppress structural vibrations, while suspension controllers based on a rigid-body model are utilized. The results of simulation demonstrate that with both methods significant reductions in structural vibrations can be achieved without sacrificing other aspects of performance, provided that modal variables for the body beaming modes are available for feedback. To simplify the implementation, suboptimal decentralized controllers using state and subsequently output feedback are developed, which are obtained by taking advantage of the separation between the natural frequencies of the rigid-body and the structural modes. For both control methods, output feedback, including the modal variables for the body beaming modes, results in performances that are close to those obtained for a full state feedback.

Control Strategies for Semi-Active Lorry Suspensions

1996 ◽  
Vol 210 (2) ◽  
pp. 161-178 ◽  
Author(s):  
D Cebon ◽  
F H Besinger ◽  
D J Cole
Keyword(s):  
Linear Models ◽  
Control Strategies ◽  
Power Input ◽  
Optimum Level ◽  
Passive Damping ◽  
Control Laws ◽  
Body Acceleration ◽  
Performance Improvements ◽  
Full State Feedback ◽  
Active Damper

The optimum level of passive damping for minimizing the root mean square (r.m.s.) dynamic tyre force and r.m.s. body acceleration of a heavy vehicle is determined by testing a damper in a ‘hardware-in-the-loop’ (HiL) test rig. Two different control strategies [‘modified skyhook damping’ (MSD), and linear optimal control with full state feedback (FSF)] are investigated theoretically using linear models, and suspension force control laws are derived. These control laws, along with simple ‘on–off’ control, are then tested experimentally using a prototype semi-active damper which is controlled so as to follow the demanded force, except when power input is required. The achievable performance improvements are compared and differences between the linear theory, computer simulations and experimental performance are discussed. It is found that using FSF control, r.m.s. body acceleration and r.m.s. tyre force can be reduced simultaneously by 28 and 21 per cent of their values for optimal passive damping.

Investigating Rigidity of Military Vehicle Body Using Operating Deflection Shape (ODS) Analysis

2006 ◽  
Vol 49 (2) ◽  
pp. 16-24 ◽  
Author(s):  
Mark Bounds ◽  
George White
Keyword(s):  
Rigid Body ◽  
Dynamic Models ◽  
The Body ◽  
Vehicle Body ◽  
Rigid Body Dynamic ◽  
Military Vehicle ◽  
Acceleration Data ◽  
Specific Frequency ◽  
Body Dynamic ◽  
Insight Into

The Army has many rigid-body dynamic models of various vehicle platforms. The adequacy of these rigid-body models has been questioned. In an effort to gain insight into the significance of flexibility in the development of dynamic vehicle models, operating deflection shape (ODS) techniques were applied to acceleration data gathered from the body of a wheeled military vehicle. The data were analyzed in an effort to determine a specific frequency range over which the assumption of rigidity would be valid. For the particular platform examined in this study, the assumption of rigidity would apply up to approximately 14 Hz. Future efforts include using operational modal analysis (OMA) to further examine the problem.

Control of Suspensions for Vehicles With Flexible Bodies—Part II: Semi-Active Suspensions

1996 ◽  
Vol 118 (3) ◽  
pp. 518-525 ◽  
Author(s):  
Aleksander Hac´ ◽  
Iljoong Youn ◽  
Hsien H. Chen
Keyword(s):  
Time Delays ◽  
Control Strategies ◽  
Structural Response ◽  
Vehicle Body ◽  
Structural Vibrations ◽  
Active Suspensions ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Sufficient Distance ◽  
Control Forces

Two methods of control of semi-active suspensions that specifically address the problem of structural vibrations of the vehicle body are considered. These control strategies are based on those developed for active suspension systems in Part I of this study and rely on either modifications of suspension control forces that account for body compliance or on the addition of a proof-mass actuator to reduce structural vibrations. A half-car model that includes body compliance is used to evaluate the effects of these control strategies on the performance of the suspensions with two-state and continuously modulated dampers. The performances of the systems are evaluated in both the time and frequency domains. The effect of time delays in the process of actuating the adjustable dampers is investigated. Significant reductions of structural vibrations are observed when the nodes of body beaming modes are a sufficient distance away from the suspension mounting points, and the time delays in the control system are negligible. The results deteriorate markedly when two-state dampers are used instead of continuously variable dampers or when a time delay in excess of 5 ms is present in the control loop. When the preference in suspension design shifts toward road holding it becomes increasingly difficult to improve the vehicle structural response without sacrificing other aspects of performance.

Output Feedback Stabilization of Uncertain Nonholonomic Chained Systems

2013 ◽  
Vol 655-657 ◽  
pp. 1354-1360
Author(s):  
Zhu Ping Wang ◽  
Zhan Ping Yuan ◽  
Qi Jun Chen
Keyword(s):  
Output Feedback ◽  
Control Strategies ◽  
Nonholonomic Systems ◽  
Feedback Stabilization ◽  
Stabilization Problem ◽  
Control Laws ◽  
Output Feedback Stabilization ◽  
System States ◽  
Chained Systems ◽  
Control Coefficients

In this paper, output feedback stabilization problem of a class of nonholonomic systems in chained form with drift nonlinearity and unknown virtual control coefficients is considered. Observer-based output feedback design is developed when only partial system states are measurable. The control laws are developed using state scaling and backstepping techniques. The proposed control strategies can steer the system globally converge to the origin.

scholarly journals Effect of compliant linkages on suspension under load

2019 ◽  
Vol 10 (2) ◽  
pp. 505-516
Author(s):  
Hsing-Hui Huang ◽  
Si-Liang Chen
Keyword(s):  
Rigid Body ◽  
High Speed ◽  
Vehicle Body ◽  
Rear Suspension ◽  
Handling Performance ◽  
Suspension Systems ◽  
Body Model ◽  
Camber Angle ◽  
Rigid Body Model ◽  
Compliance Model

Abstract. A numerical investigation is performed into the effects of rigid and compliant suspension linkages, respectively, on: the kinematics and handling performance of a lightweight electric vehicle (EV). CAE models of the front and rear suspension systems are first established based on the measured parameters of the target vehicle. The validity of the CAE models is confirmed by comparing the results obtained for the camber angle and kingpin inclination angle with those obtained mathematically using the vector loop method. CAE models are then performed using half-vehicle and whole-vehicle models. Quarter-vehicle simulations are then performed to compare the solutions obtained from the compliance and rigid-body models for the forces acting on the hardpoints of the two suspension systems under pothole impact conditions. Finally, whole-vehicle simulations are conducted using both the rigid-body model and the compliance model to evaluate the handling performance of the EV in impulse steering tests conducted at vehicle speeds of 40, 60 and 80 km h−1, respectively. In general, the results show that the choice of a rigid-body model or a compliance model has a significant effect on the forces computed at some of the hardpoints in the front and rear suspension systems. Furthermore, the rigid-body model predicts a better vehicle body stability following high-speed turns than the compliance model.

A Computational Model of Scapulo-Humeral-Clavicle Complex via Multibody Dynamics

2009 ◽  
Author(s):  
Shanzhong Shawn Duan ◽  
Keith M. Baumgarten
Keyword(s):  
Rigid Body ◽  
Soft Tissues ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
The Body ◽  
Constraint Forces ◽  
Upper Arm ◽  
Body Model ◽  
Rigid Body Model ◽  
Concentric Ball

The shoulder-upper arm complex has the most mobile joint in the body and is composed of three main bones: the collarbone (clavicle), the shoulder blade (scapula), and the upper arm bone (humerus). The shoulder joint is a non-concentric ball and socket joint. It differs from the hip, a highly stabilized, concentric ball and socket joint, that is constrained mostly by its osseous anatomy. Thus, the shoulder has more flexibility and less inherent stability than the hip because it is mainly stabilized by muscles, tendons, and ligaments. The relative decrease in stability of the shoulder compared to other joints puts the shoulder at increase risk of damage by disease or injury. The constraints added by muscles, tendons, and ligaments make modeling of the shoulder a challenge task. This paper presents a multi rigid body model to describe dynamical properties of the scapulo-humeral-clavicle complex. The bones are represented by rigid bodies, and the soft tissues (tendons, ligaments and muscles) are represented by springs and actuators attached to the rigid bodies. The rigid bodies are connected by ideal kinematic joints and have fixed centers of gravity. Equations of motion of the multi rigid body model are derived via Kane’s methods. Combination of springs and actuators includes independent variables for both motion and constraint forces, the sum of which determine the activation level.

scholarly journals Innovative concepts for the usage of veneer-based hybrid materials in vehicle structures

2021 ◽  
pp. 146442072199839
Author(s):  
DB Heyner ◽  
G Piazza ◽  
E Beeh ◽  
G Seidel ◽  
HE Friedrich ◽  
...  
Keyword(s):  
Steel Strip ◽  
High Energy ◽  
The Body ◽  
Vehicle Body ◽  
Material System ◽  
Laminated Veneer Lumber ◽  
Hybrid Beam ◽  
Bending Load ◽  
The Impact ◽  
Very High

A promising approach for the development of sustainable and resource-saving alternatives to conventional material solutions in vehicle structures is the use of renewable raw materials. One group of materials that has particular potential for this application is wood. The specific material properties of wood in the longitudinal fiber direction are comparable to typical construction materials such as steel or aluminum. Due to its comparatively low density, there is a very high lightweight construction potential especially for bending load cases. Structural components of the vehicle body are exposed to very high mechanical loads in the case of crash impact. Depending on the component under consideration, energy has to be absorbed and the structural integrity of the body has to be ensured in order to protect the occupants. The use of natural materials such as wood poses particular challenges for such applications. The material characteristics of wood are dispersed, and depend on environmental factors such as humidity. The aim of the following considerations was to develop a material system to ensure the functional reliability of the component. The test boundary conditions for validation also play a key role in this context. The potential of wood–steel hybrid design based on laminated veneer lumber and steel was investigated for use in a component subjected to crash loads such as the door impact beam. The chosen solution involves a separation of functions. A laminated veneer lumber-based beam was hybridized with a steel strip on the tension side. The steel strip was designed to compensate the comparatively low elongation at fracture of the wood and to ensure the integrity of the beam. The wooden component was designed for high energy absorption due to delamination and controlled failure during the impact, while maintaining the surface moment of inertia, i.e. the bending stiffness of the entire component. This approach was chosen to ensure the functional safety of the component, avoid sudden component failure and utilize the high potential of both materials. The tests carried out provided initial functional proof of the chosen solution. The hybridization achieved significantly higher deformations without sudden failure of the beam. In addition, bending capabilities were increased significantly compared to a beam without hybridization. In comparison with a state-of-the-art steel beam, the hybrid beam was not able to achieve the maximum deformation and the target weight of the hybrid beam. Further optimization of the hybrid beam is therefore necessary.

scholarly journals Combination of an Improved FRF-Based Substructure Synthesis and Power Flow Method with Application to Vehicle Axle Noise Analysis

2008 ◽  
Vol 15 (1) ◽  
pp. 51-60 ◽  
Author(s):  
C.Q. Liu
Keyword(s):  
Power Flow ◽  
Noise Analysis ◽  
Flow Analysis ◽  
Synthesis Method ◽  
The Body ◽  
Vehicle Body ◽  
Total System ◽  
Simple Formulation ◽  
Substructure Synthesis ◽  
Fea Model

In this paper, an improved FRF-based substructure synthesis method combined with power flow analysis is presented and is used for performing a vehicle axle noise analysis. The major transfer paths of axle noise transmitted from chassis to vehicle body are identified and ranked based on power flows transmitted through bushings between the chassis and body. To calculate the power flows, it is necessary to know the reaction forces and the vibrations at the bushing locations on the body side. To this end, the body is represented in terms of experimentally derived frequency response functions (FRF's) at the bushing locations, and the FRF's are coupled with the FEA model of the chassis for performing a total system dynamic analysis. This paper also describes how the FRF's of the vehicle body and the frequency dependent stiffness data of the bushings can be combined together with a simple formulation to better represent the dynamic characteristics of a full vehicle. A classical example is used to illustrates the concept of the method, and the method is then applied to a vehicle axle noise analysis with detailed procedure. The theoretical predictions are compared with experimentally measured results. Good correlation has been obtained.

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