- Email: [email protected]
Preview control of active suspension using disturbance of front wheel
216
Abstracts/JSAE Review 16 (1995) 211-222
vehicles. The model relevance and validity has been confirmed through experimental data. Additional applications include bond graph models of engine/transmission block dynamics, torque converter, electro-hydraulic clutch control actuators, and different (sub) systems ranging from 4WD power trains to interactive vehicle dynamics and control. These models have been useful for hardware and/or control strategy design and development.
9438358 Force Sensory Information Evaluation for Gear Changing Control for the Disabled Driver Christopher Nwagboso (Bolton Institute/U.K.), pp. 254-259, 4 figs., 7 refs. Driving of road vehicles by disabled and elderly drivers can be physically and mentally demanding tasks if the vehicle is not purposely designed for this class of driver. This is even more the case if the driving task requires changing of gears, especially if the vehicle is fitted with a manual gear system. In this paper the dynamics and sensory information required to effect gear changing by this class of drivers will be evaluated. The force sensory device designed for the experimental analysis is presented. This paper concludes by proposing a neural network for evaluating the sensory information needed for gear change control. 9438367 Numerical Analysis of Minimum-Time Cornering Takehiko Fujioka, Masaaki Kato (The University of Tokyo/Japan), pp. 260-265, 9 figs., 1 table, 4 refs. This paper investigates minimum-time cornering of a vehicle using numerical simulation based on optimal control theory instead of actual driving tests, variable. This paper indicates the results of calculations on how to control a vehicle to pass through a certain combined corner with an inclination in minimum-time. Sequential Conjugate Gradient Restoration Algorithm is used to solve optimal control problem numerically, which is often used to compute the optimal trajectory of a satellite.
9438376 A Control of Backward Maneuverability at Parking Ichiro Kageyama, Atsushi Hirata (Nihon University/Japan), pp. 266-269, 6 figs., 4 refs. This study deals with control methods of parking for a passenger car on align parking. Recently, research has been carried out to try to give unskilled driver's support, and also to try and develop autonomous vehicles. However most of them lacked an actual situation, for example narrow confines, obstacles, and so on. This study examines these missing aspect, using optimal control method when simurations of backward maneuverability for passenger car are carried out with and without swich back control, good results are oftracs. keywords: automatic parking, automatic steering, advanced vehicle control system, backward maneuverability 9438385 Autonomous Parking of Vehicles with Intelligent Fuzzy-Neural Networks Antonio Moran, Masao Nagai (Tokyo University of Agriculture and Technology/Japan), pp. 270-275, 11 figs., 5 refs. This paper presents a new design method of autonomous parking systems by integrating fuzzy systems and neural networks. First a fuzzy driver was designed based on the experience of a human driver and after it was refined by designing a fuzzy-neuro driver. The performance of both the fuzzy driver and fuzzy-neuro driver are analyzed and compared. 9438394 Tire Cornering Characteristics with Braking or Driving Force on Actual Road Mitsuhiro Makita, Shuji Torii (Nissan Motor Co., Ltd./Japan), pp. 276-280, 9 figs., 4 refs. The difference between Magic Formula tire model based on laboratory test and measurement data on various vehicle running conditions in tire side force are compared. Coefficients in Magic Formula tire model, that dominate cornering force in small slip angle region, are modified to identify with actual cornering data in each case. The fluctuation of the
modified coefficients is within 5% even in same tire and measurement system.
9438402 Tire Loads Realized Through Inertia Forces by 4 W S / 4 W D Control Haruo Shimosaka, Kosuke Matsumoto (Meiji University/Japan), pp. 281-286, 6 figs., 2 refs. The purpose of this study is to demonstrate that by utilizing the centrifugal forces of a vehicle in longitudinal and lateral directions, we can control the posture of the pitching and the rolling motion, in order to transfer the vertical load in the tires. In other words, with the control of the side slip angle, we can control the size of frictional circle by 4WS. After finishing the transfer of the tire loads, we can obtain the larger or smaller frictional circles, and then we can control the magnitude of the forces generated by the tires, in the longitudinal and the lateral direction respectively, within the frictional circle. Utilizing this control, we can make the vehicle run in the stable region of the tires and as a result, improve the stability of the vehicle when turning. 9438411 Analysis on Vehicle Stability in Critical Cornering Using Phase-Plane Method Shoji Inagaki, Ikuo Kushiro, Masaki Yamamoto (Toyota Motor Corp./Japan), pp. 287-292, 14 figs., 4 refs. Analysis on the vehicle dynamic stability in critical cornering has been carried out using the phase-plane method with the couple of the state variables, the vehicle side slip angle /3 and its angular velocity /3. The /3-/~ phase-plane analysis is more effective to represent the vehicle non-linear stability characteristic than the convetional state-plane method with the state variables fl and the yaw velocity y. The mechanism of stabilizing by counter-steering and lack of vehicle stability by excessive steering input can be explained well by the change of the characteristic on the fl-/3 phase-plane. Then it has been verified that the direct yaw moment control system by active braking with the algorithm based on the phase-plane analyses makes the vehicle stability much more in critical cornering by an experimental vehicle. 9438420 Application of a Preview Controlled Active Suspension to a (Non)linear 2-D Truck Model R.G.M. Huisman, F.E. Veldpaus, J.G.A.M. van Heck, J.J. Kok (Eindhoven University of Technology/The Netherlands), pp. 293-298, 7 figs., 17 refs. An active suspension with 'wheelbase preview' is applied to the rear axle of the tractor of a six-DOF, two-dimensional tractor-semitrailer model. The preview and state information, required to calculate the actuator force, are reconstructed from simple measurements of chassis accelerations and suspension deflections. The performance of the active suspension is evaluated in simulations for both a linear and a nonlinear truck model. It can be concluded that the active suspension combined with the reconstruction technique improves the chassis accelerations at the rear wheels of the tractor significantly with only a small increase of the dynamic tire force and suspension deflection. Moreover, the suspension appears to be robust for the nonlinearities introduced. However, the simple observer model causes disappointing results with respect to the dynamic tire force and suspension deflection. 9438439 Preview Control of Active Suspension Using Disturbance of Front Wheel Yoshiaki Araki, Masahiro Oya (Kyushu Institute of Technology/Japan), Hiroshi Harada (National Defense Academy/Japan), pp. 299-304, 10 figs., 9 refs. The main body of this investigation focuses on the development of an analytical and numerical design procedure of an effective controller of an active vehicle suspension system, using a preview control by front wheel disturbance. The theoretical aspects of an optimal preview control using with a front road disturbance which is identified from a response of front-wheel is presented. The performance indices employed are weighted sum of a pitching angle and a bouncing of sprung mass with two wheeled two degree-of-freedom half car model. Computer simulation results show
Abstracts /JSAE Review 16 (1995) 211-222
217
the advantages of the control with feed-forward compensation of the rear active suspension using with the front wheel disturbance.
attitude control is discussed in section 1 and vibration control will be entered into detail in section 2.
9438448 Continuously Controlled Semi-Active Suspension Using Neural Networks Antonio Moran, Tomohiro Hasegawa, Masao Nagai (Tokyo
9438475 A Controlled Suspension System with Continuously Adjustable Damping Force Stephan Irmscher, Eberhard Hees, Thomas
University of Agriculture and Technology/Japan), pp. 305-310, 11 figs., 4 refs. This paper presents a new design method of nonlinear semi-active suspensions based on the integration of neural networks and bilinear systems. It is known that semi-active suspensions with ideal linear components have a bilinear structure. However actual semi-active suspensions with nonlinear components have an structure which is not purely bilinear. In order to improve the performance of semi-active suspensions, nonlinear neural networks and bilinear systems are integrated and used for the identification and optimal control of nonlinar semi-active suspensions. The validity and applicability of the proposed method are analyzed and verified theoretically and experimentally using a semi-active suspension model equipped with fast-response piezo-electric actuators.
Kutsche (Fichtel & Sachs AG/Germany), pp. 325-330, 7 figs., 3 refs. A controlled highly dynamic suspension system realized in an upper mid-size car will be described in the article. The aim of the works was to improve both comfort and ensure high driving safety. The designed multivariable controller is based on an optimal state-variable controller. Every module of the controller generates state-dependent damping forces which are coordinated state-dependently. The problem of integration of the accelerations free from phase shift error was solved. The estimation of the states by optimal state estimators will be regarded as alternative in case of highly disturbed measurements. The nonlinear damping characteristic as a function of the piston velocity is included in the controller. The number of sensors is limited to the sensors absolutely necessary. The minimal number of sensors is derived from simulations and tests. Continuously adjustable high-speed proportional valves are an essential part of the system. They allow to reproduce purpose*made damping force curves and in case of an error they go into the fail-safe state. The driving tests showed very good results regarding the vertical stabilization of the body, the reaction to bad road conditions and the correction of pitch and roll. With such a cost-effective solution improvements were reached almost similar to the results of active systems. Many measurements verify the efficiency of the controller. The tests were carried out not only on the four-post shaker but also in test rides on real roads.
9438457 An Actively Damped Passenger Car Suspension System With Low Voltage Electro.Rheological Magnetic Fluid Andrew Pinkos, Emil Shtarkman, Thomas Fitzgerald (TRW, Inc./U.S.A.), pp. 311-317, 13 figs. In the realm of "semi-active" suspension systems, this paper describes a truly "active damping" system. Thorough research and development of low voltage Electro-Rheological Magnetic (ERM) fluids, a revived rotary shock absorber suspension philosophy and a newly developed control algorithm have resulted in an active damping system that resolves the selection between ride comfort and handling performance. The ERM fluid technology, rotary shock absorber configuration and Digital Signal Processor (DSP) technology have advantages of transmitting high forces in a small compact package. The DSP controls the elements that digitize analog sensor signals and through software, result in active damping. We call the actuator the Rotary Active Control Damper (RACD, pronounced "rack-dee"). The variety of on-board sensors makes it possible to adjust vehicle performance through software. Mathematical analysis, computer simulations, and actual vehicle testing of the developed algorithm in which RACD is the damping actuator have shown the advantage of the developed technology. The system can be operational in either an open or closed-loop form for optimum continuous control of the active damper. Actual vehicle installation of RACD's with extensive testing have shown that this is a practical alternative to today's multi-damping shock absorbers.
9438466 Evaluation and Practical Implementation of a Low Power Attitude and Vibration Control System A.C.M. van der Knaap (Delft University of Technology/The Netherlands), P.J.Th. Venhovens (The University of Michigan/U.S.A.), H.B. Pacejka (Delft University of Technology/The Netherlands), pp. 318-324, 9 figs., 1 table, 5 refs. The paper deals with the evaluation of the ride and handling of a vehicle equipped with a low power active suspension system. The suspension of a standard Volvo 480 ES has been extended with a newly developed actuator system and road tests have been carried out in order to review the performance. This suspension system was firstly presented at the AVEC'92 conference [1] and is called Delft Active Suspension (DAS). It is able to suppress the low frequency sprung mass motions (such as roll during cornering and pitch during braking or accelerating) using only a small amount of energy. Besides attitude control DAS can also be used for improving the ride when the vehicle operates on an uneven road. The vibration control as used in DAS is based on the feedback of the absolute vertical sprung mass velocities at each of the four wheel suspensions. It improves the ride with respect to the road unevennesses in the frequency range from 0.5-2.5 Hz. The energy consumption for vibration control has somewhat increased compared with attitude control. However, it is still acceptably low. The evaluation of
9438484 Development of the Active Damper Suspension Kazuhiro Higashiyama, Toshirou Hirai, Shinobu Kakizaki, Michiya Hiramoto (Nissan Motor. Co,, Ltd./Japan), pp. 331-336, 16 figs., 1 table, 3 refs. We have developed and put into practical use the "Active Damper Suspension" in which the "Skyhook Control"-a highly regarded principle applied to conventional hydraulic active suspension-is realized by controlling the damping force of the dampers. In developing this new suspension system, we have reviewed and examined the fundamental function of automotive suspension. As a result of this effort, we were able to develop an unprecedented combination of smooth riding comfort and well-damped firm driving performance by adjusting the damping force to the most favorable condition in accordance with vehicle behavior and input from the road surface on a real time basis. In this paper, we will describe our aims for the development of this system, the system configuration, the operating mechanism and the effect of this system. 9438493 Active Roll Control and Roll Distribution Control for Ground Vehicle Soo-Min Hwang (Daewoo Motor Co./Korea), Youngjin Park (Kaist/Korea), pp. 337-342, 11 figs., 1 table, 10 refs. Active roll control based on predictive control theory is proposed to overcome the detrimental effects of time delay of the hydraulic actuators. Predictive controller is developed based on the simplified linear model of the vehicle, while the simulation is performed on the nonlinear model. The control result is superior compared to that of the conventional feed-forward roll control. A vehicle tends to drift or spin during cornering simultaneously with braking or acceleration, because of the nonlinear characteristics of tire side force. A novel roll distribution control scheme is developed to improve the trajectory stability during aforementioned situation by changing the ratio of active roll moment distribution to front and real axles. The effectiveness of the proposed methods are illustrated by the computer simulations.
9438501 Feasibility Study of Active Roll Stabilizer for Reducing Roll Angle of an Experimental Medium-Duty Truck Yuhji Kusahara, Xiansheng Li, Nobuo Hata, Yoshito Watanabe (Nissan Diesel Motor Co., Ltd./Japan), pp. 343-348, 12 figs., 3 refs.
Abstracts/JSAE Review 16 (1995) 211-222
vehicles. The model relevance and validity has been confirmed through experimental data. Additional applications include bond graph models of engine/transmission block dynamics, torque converter, electro-hydraulic clutch control actuators, and different (sub) systems ranging from 4WD power trains to interactive vehicle dynamics and control. These models have been useful for hardware and/or control strategy design and development.
9438358 Force Sensory Information Evaluation for Gear Changing Control for the Disabled Driver Christopher Nwagboso (Bolton Institute/U.K.), pp. 254-259, 4 figs., 7 refs. Driving of road vehicles by disabled and elderly drivers can be physically and mentally demanding tasks if the vehicle is not purposely designed for this class of driver. This is even more the case if the driving task requires changing of gears, especially if the vehicle is fitted with a manual gear system. In this paper the dynamics and sensory information required to effect gear changing by this class of drivers will be evaluated. The force sensory device designed for the experimental analysis is presented. This paper concludes by proposing a neural network for evaluating the sensory information needed for gear change control. 9438367 Numerical Analysis of Minimum-Time Cornering Takehiko Fujioka, Masaaki Kato (The University of Tokyo/Japan), pp. 260-265, 9 figs., 1 table, 4 refs. This paper investigates minimum-time cornering of a vehicle using numerical simulation based on optimal control theory instead of actual driving tests, variable. This paper indicates the results of calculations on how to control a vehicle to pass through a certain combined corner with an inclination in minimum-time. Sequential Conjugate Gradient Restoration Algorithm is used to solve optimal control problem numerically, which is often used to compute the optimal trajectory of a satellite.
9438376 A Control of Backward Maneuverability at Parking Ichiro Kageyama, Atsushi Hirata (Nihon University/Japan), pp. 266-269, 6 figs., 4 refs. This study deals with control methods of parking for a passenger car on align parking. Recently, research has been carried out to try to give unskilled driver's support, and also to try and develop autonomous vehicles. However most of them lacked an actual situation, for example narrow confines, obstacles, and so on. This study examines these missing aspect, using optimal control method when simurations of backward maneuverability for passenger car are carried out with and without swich back control, good results are oftracs. keywords: automatic parking, automatic steering, advanced vehicle control system, backward maneuverability 9438385 Autonomous Parking of Vehicles with Intelligent Fuzzy-Neural Networks Antonio Moran, Masao Nagai (Tokyo University of Agriculture and Technology/Japan), pp. 270-275, 11 figs., 5 refs. This paper presents a new design method of autonomous parking systems by integrating fuzzy systems and neural networks. First a fuzzy driver was designed based on the experience of a human driver and after it was refined by designing a fuzzy-neuro driver. The performance of both the fuzzy driver and fuzzy-neuro driver are analyzed and compared. 9438394 Tire Cornering Characteristics with Braking or Driving Force on Actual Road Mitsuhiro Makita, Shuji Torii (Nissan Motor Co., Ltd./Japan), pp. 276-280, 9 figs., 4 refs. The difference between Magic Formula tire model based on laboratory test and measurement data on various vehicle running conditions in tire side force are compared. Coefficients in Magic Formula tire model, that dominate cornering force in small slip angle region, are modified to identify with actual cornering data in each case. The fluctuation of the
modified coefficients is within 5% even in same tire and measurement system.
9438402 Tire Loads Realized Through Inertia Forces by 4 W S / 4 W D Control Haruo Shimosaka, Kosuke Matsumoto (Meiji University/Japan), pp. 281-286, 6 figs., 2 refs. The purpose of this study is to demonstrate that by utilizing the centrifugal forces of a vehicle in longitudinal and lateral directions, we can control the posture of the pitching and the rolling motion, in order to transfer the vertical load in the tires. In other words, with the control of the side slip angle, we can control the size of frictional circle by 4WS. After finishing the transfer of the tire loads, we can obtain the larger or smaller frictional circles, and then we can control the magnitude of the forces generated by the tires, in the longitudinal and the lateral direction respectively, within the frictional circle. Utilizing this control, we can make the vehicle run in the stable region of the tires and as a result, improve the stability of the vehicle when turning. 9438411 Analysis on Vehicle Stability in Critical Cornering Using Phase-Plane Method Shoji Inagaki, Ikuo Kushiro, Masaki Yamamoto (Toyota Motor Corp./Japan), pp. 287-292, 14 figs., 4 refs. Analysis on the vehicle dynamic stability in critical cornering has been carried out using the phase-plane method with the couple of the state variables, the vehicle side slip angle /3 and its angular velocity /3. The /3-/~ phase-plane analysis is more effective to represent the vehicle non-linear stability characteristic than the convetional state-plane method with the state variables fl and the yaw velocity y. The mechanism of stabilizing by counter-steering and lack of vehicle stability by excessive steering input can be explained well by the change of the characteristic on the fl-/3 phase-plane. Then it has been verified that the direct yaw moment control system by active braking with the algorithm based on the phase-plane analyses makes the vehicle stability much more in critical cornering by an experimental vehicle. 9438420 Application of a Preview Controlled Active Suspension to a (Non)linear 2-D Truck Model R.G.M. Huisman, F.E. Veldpaus, J.G.A.M. van Heck, J.J. Kok (Eindhoven University of Technology/The Netherlands), pp. 293-298, 7 figs., 17 refs. An active suspension with 'wheelbase preview' is applied to the rear axle of the tractor of a six-DOF, two-dimensional tractor-semitrailer model. The preview and state information, required to calculate the actuator force, are reconstructed from simple measurements of chassis accelerations and suspension deflections. The performance of the active suspension is evaluated in simulations for both a linear and a nonlinear truck model. It can be concluded that the active suspension combined with the reconstruction technique improves the chassis accelerations at the rear wheels of the tractor significantly with only a small increase of the dynamic tire force and suspension deflection. Moreover, the suspension appears to be robust for the nonlinearities introduced. However, the simple observer model causes disappointing results with respect to the dynamic tire force and suspension deflection. 9438439 Preview Control of Active Suspension Using Disturbance of Front Wheel Yoshiaki Araki, Masahiro Oya (Kyushu Institute of Technology/Japan), Hiroshi Harada (National Defense Academy/Japan), pp. 299-304, 10 figs., 9 refs. The main body of this investigation focuses on the development of an analytical and numerical design procedure of an effective controller of an active vehicle suspension system, using a preview control by front wheel disturbance. The theoretical aspects of an optimal preview control using with a front road disturbance which is identified from a response of front-wheel is presented. The performance indices employed are weighted sum of a pitching angle and a bouncing of sprung mass with two wheeled two degree-of-freedom half car model. Computer simulation results show
Abstracts /JSAE Review 16 (1995) 211-222
217
the advantages of the control with feed-forward compensation of the rear active suspension using with the front wheel disturbance.
attitude control is discussed in section 1 and vibration control will be entered into detail in section 2.
9438448 Continuously Controlled Semi-Active Suspension Using Neural Networks Antonio Moran, Tomohiro Hasegawa, Masao Nagai (Tokyo
9438475 A Controlled Suspension System with Continuously Adjustable Damping Force Stephan Irmscher, Eberhard Hees, Thomas
University of Agriculture and Technology/Japan), pp. 305-310, 11 figs., 4 refs. This paper presents a new design method of nonlinear semi-active suspensions based on the integration of neural networks and bilinear systems. It is known that semi-active suspensions with ideal linear components have a bilinear structure. However actual semi-active suspensions with nonlinear components have an structure which is not purely bilinear. In order to improve the performance of semi-active suspensions, nonlinear neural networks and bilinear systems are integrated and used for the identification and optimal control of nonlinar semi-active suspensions. The validity and applicability of the proposed method are analyzed and verified theoretically and experimentally using a semi-active suspension model equipped with fast-response piezo-electric actuators.
Kutsche (Fichtel & Sachs AG/Germany), pp. 325-330, 7 figs., 3 refs. A controlled highly dynamic suspension system realized in an upper mid-size car will be described in the article. The aim of the works was to improve both comfort and ensure high driving safety. The designed multivariable controller is based on an optimal state-variable controller. Every module of the controller generates state-dependent damping forces which are coordinated state-dependently. The problem of integration of the accelerations free from phase shift error was solved. The estimation of the states by optimal state estimators will be regarded as alternative in case of highly disturbed measurements. The nonlinear damping characteristic as a function of the piston velocity is included in the controller. The number of sensors is limited to the sensors absolutely necessary. The minimal number of sensors is derived from simulations and tests. Continuously adjustable high-speed proportional valves are an essential part of the system. They allow to reproduce purpose*made damping force curves and in case of an error they go into the fail-safe state. The driving tests showed very good results regarding the vertical stabilization of the body, the reaction to bad road conditions and the correction of pitch and roll. With such a cost-effective solution improvements were reached almost similar to the results of active systems. Many measurements verify the efficiency of the controller. The tests were carried out not only on the four-post shaker but also in test rides on real roads.
9438457 An Actively Damped Passenger Car Suspension System With Low Voltage Electro.Rheological Magnetic Fluid Andrew Pinkos, Emil Shtarkman, Thomas Fitzgerald (TRW, Inc./U.S.A.), pp. 311-317, 13 figs. In the realm of "semi-active" suspension systems, this paper describes a truly "active damping" system. Thorough research and development of low voltage Electro-Rheological Magnetic (ERM) fluids, a revived rotary shock absorber suspension philosophy and a newly developed control algorithm have resulted in an active damping system that resolves the selection between ride comfort and handling performance. The ERM fluid technology, rotary shock absorber configuration and Digital Signal Processor (DSP) technology have advantages of transmitting high forces in a small compact package. The DSP controls the elements that digitize analog sensor signals and through software, result in active damping. We call the actuator the Rotary Active Control Damper (RACD, pronounced "rack-dee"). The variety of on-board sensors makes it possible to adjust vehicle performance through software. Mathematical analysis, computer simulations, and actual vehicle testing of the developed algorithm in which RACD is the damping actuator have shown the advantage of the developed technology. The system can be operational in either an open or closed-loop form for optimum continuous control of the active damper. Actual vehicle installation of RACD's with extensive testing have shown that this is a practical alternative to today's multi-damping shock absorbers.
9438466 Evaluation and Practical Implementation of a Low Power Attitude and Vibration Control System A.C.M. van der Knaap (Delft University of Technology/The Netherlands), P.J.Th. Venhovens (The University of Michigan/U.S.A.), H.B. Pacejka (Delft University of Technology/The Netherlands), pp. 318-324, 9 figs., 1 table, 5 refs. The paper deals with the evaluation of the ride and handling of a vehicle equipped with a low power active suspension system. The suspension of a standard Volvo 480 ES has been extended with a newly developed actuator system and road tests have been carried out in order to review the performance. This suspension system was firstly presented at the AVEC'92 conference [1] and is called Delft Active Suspension (DAS). It is able to suppress the low frequency sprung mass motions (such as roll during cornering and pitch during braking or accelerating) using only a small amount of energy. Besides attitude control DAS can also be used for improving the ride when the vehicle operates on an uneven road. The vibration control as used in DAS is based on the feedback of the absolute vertical sprung mass velocities at each of the four wheel suspensions. It improves the ride with respect to the road unevennesses in the frequency range from 0.5-2.5 Hz. The energy consumption for vibration control has somewhat increased compared with attitude control. However, it is still acceptably low. The evaluation of
9438484 Development of the Active Damper Suspension Kazuhiro Higashiyama, Toshirou Hirai, Shinobu Kakizaki, Michiya Hiramoto (Nissan Motor. Co,, Ltd./Japan), pp. 331-336, 16 figs., 1 table, 3 refs. We have developed and put into practical use the "Active Damper Suspension" in which the "Skyhook Control"-a highly regarded principle applied to conventional hydraulic active suspension-is realized by controlling the damping force of the dampers. In developing this new suspension system, we have reviewed and examined the fundamental function of automotive suspension. As a result of this effort, we were able to develop an unprecedented combination of smooth riding comfort and well-damped firm driving performance by adjusting the damping force to the most favorable condition in accordance with vehicle behavior and input from the road surface on a real time basis. In this paper, we will describe our aims for the development of this system, the system configuration, the operating mechanism and the effect of this system. 9438493 Active Roll Control and Roll Distribution Control for Ground Vehicle Soo-Min Hwang (Daewoo Motor Co./Korea), Youngjin Park (Kaist/Korea), pp. 337-342, 11 figs., 1 table, 10 refs. Active roll control based on predictive control theory is proposed to overcome the detrimental effects of time delay of the hydraulic actuators. Predictive controller is developed based on the simplified linear model of the vehicle, while the simulation is performed on the nonlinear model. The control result is superior compared to that of the conventional feed-forward roll control. A vehicle tends to drift or spin during cornering simultaneously with braking or acceleration, because of the nonlinear characteristics of tire side force. A novel roll distribution control scheme is developed to improve the trajectory stability during aforementioned situation by changing the ratio of active roll moment distribution to front and real axles. The effectiveness of the proposed methods are illustrated by the computer simulations.
9438501 Feasibility Study of Active Roll Stabilizer for Reducing Roll Angle of an Experimental Medium-Duty Truck Yuhji Kusahara, Xiansheng Li, Nobuo Hata, Yoshito Watanabe (Nissan Diesel Motor Co., Ltd./Japan), pp. 343-348, 12 figs., 3 refs.