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Evaluation and practical implementation of a low power attitude and vibration control system
Abstracts /JSAE Review 16 (1995) 211-222
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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.
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.