- Email: [email protected]
Yaw rate and lateral acceleration feedback for four-wheel steering
214
Abstracts/JSAE Review 16 (1995) 211-222
suhiro Ueda, Antonio Moran (Tokyo University of Agriculture and Technology/Japan), pp. 153-158, 13 figs., 1 table, 6 refs. Four-wheel-steering (4WS) systems have been studied and developed with remarkable success from the viewpoint of vehicle dynamics. Most of the control methods require a liuearized bicycle model of the actual vehicle system which is however strongly influenced by tire nonlinearity especially in critical situations such as emergent maneuver for collision avoidance on slippery road surface. This paper proposes a new method to design the 4WS system taking into account the nonlinear characteristics of tires and suspensions. For this purpose the new method using artificial neural network and linear control theory is analyzed and applied to the identification and control of a nonlinear vehicle model structured using a software for multi-body dynamic analysis (ADAMS). This model takes into account the nonlinear characteristics of actual vehicles with tires which are modeled by "magic formula". The results of computer simulation show that the proposed method using neural network can be efficiently used to improve the handling and stability of vehicles.
9438196 Comparison of 4WS and Direct Yaw Moment Control (DYC) for Improvement of Vehicle Handling Performance Masato Abe, Naoto Ohkubo, Yoshio Kano (Kanagawa Institute of Technology/ Japan), pp. 159-164, 8 figs., 3 refs. Zero side slip and the first order lag yaw rate model following control laws for the direct yaw moment control and four wheel steer are introduced. The effects of these control on improving active safety of vehicle handling are investigated with computer simulations. It is found that the yaw rate model following direct yaw moment control has a greater effect on improving vehicle handling especially during severe maneuvering range than the four wheel steer. 9438204 Yaw Rate and Lateral Acceleration Feedback for Four-Wheel Steering Jiirgen Ackermann (DLR/Germany), pp. 165-170, 6 figs., 10 refs. First the lateral and yaw motions are decoupled by yaw rate feedback to active front wheel steering. This decoupling property is robust with respect to uncertain mass, velocity and tire side-force characteristics. Second, an ideal unity steering transfer function is obtained by feedback of the lateral acceleration at the front axle to front wheel steering. Third, velocity invariant yaw dynamics with tunable yaw damping are obtained by feedback of the yaw rate to rear-wheel steering.
A control strategy for a two-state damper of a semi-active truck suspension system is developed. Three main design demands can be distinguished: low values of the body acceleration to ensure 'good' comfort, low dynamic tire forces and a small suspension working space. The purpose of the controller is to improve the performance with respect to one of these demands and to keep the performance with respect to the other demands between certain limits. The control strategy uses the 'dynamic programming procedure'. The behaviour of the semi-active suspension with this strategy is tested on rounded pulses and is compared with the behaviour of a passive suspension.
9438231 Design of IMC Structured Automotive Semi-Active Damping Controller Sejin Park, Jakyum Koo (Ssang Yong Motor Company/Korea), pp. 183-188, 12 figs., 6 refs. In this paper, a novel sky-hook style semi-active control scheme is proposed by using IMC(Interual Model Control). In practical application, actuator is constrained within upper and lower bound, especially for a semi-active suspension system. The proposed scheme is effective for this kind of non-linearity compensation, and shows improved performance comparing with conventional skyhook based control system. The restilt is synthesized by simulation. 9438240 A Genetic Algorithm Based Fuzzy System for Semi-Active Suspension System Design Edge C. Yeh, Shao How Lu, Chin Chih Chen (National Tsing Hua University/Taiwan R.O.C.), pp. 189-194, 10 figs., 2 tables, 7 refs. In this study, a genetic algorithm (GA) based fuzzy system is developed to generate a rule table automatically for a fuzzy semi-active suspension system design. For implementation, a nonlinear damper is considered with the damping characteristics of a variable orifice to develop a controller to control the metering orifice area directly. In order to select a proper fuzzy rule table for the introduced nonlinear damper, the chromosome of GA is decoded into a code string of fuzzy membership functions and the corresponding fuzzy rule table entries for evolution. In GA, the evaluation function measures only the acceleration of the sprung mass for ride comfort. Simulations of a quarter car model with linear and nonlinear dampers are carried out for comparison. A random road profile is used in the simulation. Simulation results show that the proposed approach can learn the control strategy for semi active suspention systems.
9438213 A Study on the Development of Active Damper System with Electric Motor Driven Orifice Scok-Jae Yoon (MANO Motor Co./Korea), Sung Bin Han (Induk Institute of Design/Korea), pp. 171-176, 6 figs., 1 table, 16 refs. A viable solution, to the compromise in a passive suspension system, is presented in this paper. The use of active damping gives substantial comfort, safety, and performance gains over the passive suspension system. This system will minimize the effects of acceleration lift, braking dip, body roll and road shock without sacrificing handling quality. This suspension system uses the conventional hardware of a passive system combined with the sensors and ride leveling components of an active suspension system. Therefore, this system is in essence a compromise between fully active and passive suspension, allowing lower cost but sacrificing the versatility and quality of an active suspension system. It is our intension to give the damper a greater variation of rate than three types of usual semi-active suspension system. The design utilizes a rotating orifice plate by electric motor to control the flow rate. Widely, resulting in a adjustable damping rate, the means of controlling the orifice plate is also supplied, along with a control system that achieves the desired comfort standards.
9438259 A Robust Semi.active Suspension Control Law to Improve Ride Quality Kyongsu Yi (Hanyang University/Korea), Taeil Oh, Myung W. Suh (Kia Motors Corp./Korea), pp. 195-199, 8 figs., 9 refs. This paper deals with a robust semi-active control algorithm which is applicable to a semi-active suspension with a multi-state damper. Most of the literature to date has focused on the control of damping rate of a semi-active force element assuming that the desired damping rate can be instantaneously produced. However, since the controllable damping rates are discrete in case of a multi-state semi-active damper, the desired damping rate can not be produced exactly even if force-velocity relations of a multi-state semi-active damper is completely known. In addition, damping characteristics of the semi-active dampers are different from damper to damper. A robust nonlinear control law is developed. The main objective of the proposed control strategies is to improve ride quality by tracking the desired active force with a multi-state semi-active damper of which the force-velocity relationships are " n o t " completely known. The performance of the proposed semi-active control law is numerically compared to those of the control law based on the bilinear model and a passive suspension. The proposed control algorithm is robust to nonlinear characteristics and uncertainty of the force-velocity relationships of a multi-state damper.
9438222 A Semi-Active Suspension System based on Dynamic Programming J.H.E.A. Muijderman, F.E. Veldpans, J.J. Kok (Eindhoven University of Technology/The Netherlands), pp. 177-182, 4 figs., 5 refs.
9438268 Adaptive Control of Semi-Active Suspension for All-Service Vehicle Dafeng Jin, Yiming Zhang (Beijing Institute of Teehnology/P.R. of China), pp. 200-205, 19 figs., 1 refs.
Abstracts/JSAE Review 16 (1995) 211-222
suhiro Ueda, Antonio Moran (Tokyo University of Agriculture and Technology/Japan), pp. 153-158, 13 figs., 1 table, 6 refs. Four-wheel-steering (4WS) systems have been studied and developed with remarkable success from the viewpoint of vehicle dynamics. Most of the control methods require a liuearized bicycle model of the actual vehicle system which is however strongly influenced by tire nonlinearity especially in critical situations such as emergent maneuver for collision avoidance on slippery road surface. This paper proposes a new method to design the 4WS system taking into account the nonlinear characteristics of tires and suspensions. For this purpose the new method using artificial neural network and linear control theory is analyzed and applied to the identification and control of a nonlinear vehicle model structured using a software for multi-body dynamic analysis (ADAMS). This model takes into account the nonlinear characteristics of actual vehicles with tires which are modeled by "magic formula". The results of computer simulation show that the proposed method using neural network can be efficiently used to improve the handling and stability of vehicles.
9438196 Comparison of 4WS and Direct Yaw Moment Control (DYC) for Improvement of Vehicle Handling Performance Masato Abe, Naoto Ohkubo, Yoshio Kano (Kanagawa Institute of Technology/ Japan), pp. 159-164, 8 figs., 3 refs. Zero side slip and the first order lag yaw rate model following control laws for the direct yaw moment control and four wheel steer are introduced. The effects of these control on improving active safety of vehicle handling are investigated with computer simulations. It is found that the yaw rate model following direct yaw moment control has a greater effect on improving vehicle handling especially during severe maneuvering range than the four wheel steer. 9438204 Yaw Rate and Lateral Acceleration Feedback for Four-Wheel Steering Jiirgen Ackermann (DLR/Germany), pp. 165-170, 6 figs., 10 refs. First the lateral and yaw motions are decoupled by yaw rate feedback to active front wheel steering. This decoupling property is robust with respect to uncertain mass, velocity and tire side-force characteristics. Second, an ideal unity steering transfer function is obtained by feedback of the lateral acceleration at the front axle to front wheel steering. Third, velocity invariant yaw dynamics with tunable yaw damping are obtained by feedback of the yaw rate to rear-wheel steering.
A control strategy for a two-state damper of a semi-active truck suspension system is developed. Three main design demands can be distinguished: low values of the body acceleration to ensure 'good' comfort, low dynamic tire forces and a small suspension working space. The purpose of the controller is to improve the performance with respect to one of these demands and to keep the performance with respect to the other demands between certain limits. The control strategy uses the 'dynamic programming procedure'. The behaviour of the semi-active suspension with this strategy is tested on rounded pulses and is compared with the behaviour of a passive suspension.
9438231 Design of IMC Structured Automotive Semi-Active Damping Controller Sejin Park, Jakyum Koo (Ssang Yong Motor Company/Korea), pp. 183-188, 12 figs., 6 refs. In this paper, a novel sky-hook style semi-active control scheme is proposed by using IMC(Interual Model Control). In practical application, actuator is constrained within upper and lower bound, especially for a semi-active suspension system. The proposed scheme is effective for this kind of non-linearity compensation, and shows improved performance comparing with conventional skyhook based control system. The restilt is synthesized by simulation. 9438240 A Genetic Algorithm Based Fuzzy System for Semi-Active Suspension System Design Edge C. Yeh, Shao How Lu, Chin Chih Chen (National Tsing Hua University/Taiwan R.O.C.), pp. 189-194, 10 figs., 2 tables, 7 refs. In this study, a genetic algorithm (GA) based fuzzy system is developed to generate a rule table automatically for a fuzzy semi-active suspension system design. For implementation, a nonlinear damper is considered with the damping characteristics of a variable orifice to develop a controller to control the metering orifice area directly. In order to select a proper fuzzy rule table for the introduced nonlinear damper, the chromosome of GA is decoded into a code string of fuzzy membership functions and the corresponding fuzzy rule table entries for evolution. In GA, the evaluation function measures only the acceleration of the sprung mass for ride comfort. Simulations of a quarter car model with linear and nonlinear dampers are carried out for comparison. A random road profile is used in the simulation. Simulation results show that the proposed approach can learn the control strategy for semi active suspention systems.
9438213 A Study on the Development of Active Damper System with Electric Motor Driven Orifice Scok-Jae Yoon (MANO Motor Co./Korea), Sung Bin Han (Induk Institute of Design/Korea), pp. 171-176, 6 figs., 1 table, 16 refs. A viable solution, to the compromise in a passive suspension system, is presented in this paper. The use of active damping gives substantial comfort, safety, and performance gains over the passive suspension system. This system will minimize the effects of acceleration lift, braking dip, body roll and road shock without sacrificing handling quality. This suspension system uses the conventional hardware of a passive system combined with the sensors and ride leveling components of an active suspension system. Therefore, this system is in essence a compromise between fully active and passive suspension, allowing lower cost but sacrificing the versatility and quality of an active suspension system. It is our intension to give the damper a greater variation of rate than three types of usual semi-active suspension system. The design utilizes a rotating orifice plate by electric motor to control the flow rate. Widely, resulting in a adjustable damping rate, the means of controlling the orifice plate is also supplied, along with a control system that achieves the desired comfort standards.
9438259 A Robust Semi.active Suspension Control Law to Improve Ride Quality Kyongsu Yi (Hanyang University/Korea), Taeil Oh, Myung W. Suh (Kia Motors Corp./Korea), pp. 195-199, 8 figs., 9 refs. This paper deals with a robust semi-active control algorithm which is applicable to a semi-active suspension with a multi-state damper. Most of the literature to date has focused on the control of damping rate of a semi-active force element assuming that the desired damping rate can be instantaneously produced. However, since the controllable damping rates are discrete in case of a multi-state semi-active damper, the desired damping rate can not be produced exactly even if force-velocity relations of a multi-state semi-active damper is completely known. In addition, damping characteristics of the semi-active dampers are different from damper to damper. A robust nonlinear control law is developed. The main objective of the proposed control strategies is to improve ride quality by tracking the desired active force with a multi-state semi-active damper of which the force-velocity relationships are " n o t " completely known. The performance of the proposed semi-active control law is numerically compared to those of the control law based on the bilinear model and a passive suspension. The proposed control algorithm is robust to nonlinear characteristics and uncertainty of the force-velocity relationships of a multi-state damper.
9438222 A Semi-Active Suspension System based on Dynamic Programming J.H.E.A. Muijderman, F.E. Veldpans, J.J. Kok (Eindhoven University of Technology/The Netherlands), pp. 177-182, 4 figs., 5 refs.
9438268 Adaptive Control of Semi-Active Suspension for All-Service Vehicle Dafeng Jin, Yiming Zhang (Beijing Institute of Teehnology/P.R. of China), pp. 200-205, 19 figs., 1 refs.