The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform
Daniele Dini - One of the best experts on this subject based on the ideXlab platform.
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robust control for a full car prototype of series Active Variable geometry suspension
Conference on Decision and Control, 2019Co-Authors: Min Yu, Simos A. Evangelou, Cheng Cheng, Daniele DiniAbstract:The Series Active Variable Geometry Suspension (SAVGS) which has been recently proposed shows promising potential in terms of suspension performance enhancement, limited power consumption and so on. In this paper, the control aspects of a full-car prototype with the front axle retrofitted by the SAVGS, which is developed to validate the practical feasibility of the novel mechatronic suspension, are addressed. Two 12 V dc batteries and one DC/AC inverter constitute an independent power source that supplies the overall embedded mechatronic system, with two AC rotary servo motors driving the single links (in the SAVGS) at two front corners, respectively. A robust control scheme, with an outer-loop H-infinity control and an inner-loop actuator velocity tracking control, is synthesized to enhance the vehicle ride comfort and road holding performance. Numerical simulations of the full-car prototype, with the typical road events of a 2 Hz harmonic road, and a speed hump tested, are performed. The results of numerical simulations indicate the potential suspension performance improvement contributed by the SAVGS and the power usage in the batteries, which will be compared in the future with the upcoming experimental testing results of the prototype on-road driving.
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quarter car experimental study for series Active Variable geometry suspension
IEEE Transactions on Control Systems and Technology, 2019Co-Authors: Min Yu, Simos A. Evangelou, Carlos Arana, Daniele DiniAbstract:In this paper, the recently introduced series Active Variable geometry suspension (SAVGS) for road vehicles is experimentally studied. A realistic quarter-car test rig equipped with double-wishbone suspension is designed and built to mimic an actual grand tourer real axle, with a single-link variant of the SAVGS and a road excitation mechanism implemented. A linear equivalent modeling method is adopted to synthesize an H-infinity control scheme for the SAVGS, with the geometric nonlinearity compensated. Simulations with a theoretical nonlinear quarter-car indicate the SAVGS potential to enhance suspension performance, in terms of ride comfort and road holding. Practical features in the test rig are further considered and included in the nonlinear model to compensate the difference between the theoretical and testing behaviors. Experiments with a sinusoidal road, a smoothed bump and hole, and a random road are performed to evaluate the SAVGS practical feasibility and performance improvement, the accuracy of the model, and the robustness of the control schemes. Compared with the conventional passive suspension, ride comfort improvements of up to 41% without any deterioration of the suspension deflection are demonstrated, while the SAVGS actuator power is kept very low, at levels below 500 W.
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model identification and control for a quarter car test rig of series Active Variable geometry suspension
IFAC-PapersOnLine, 2017Co-Authors: Min Yu, Simos A. Evangelou, Daniele DiniAbstract:Abstract In this paper, a quarter car test rig is utilized to perform an experimental study of the single-link variant of the Series Active Variable Geometry Suspension (SAVGS). A nonlinear model of the test rig is identified with the use of a theoretical quarter car model and the rig’s experimental frequency response. A linear equivalent modeling method that compensates the geometric nonlinearity is also adopted to synthesize an H-infinity control scheme. The controller Actively adjusts the single-link velocity in the SAVGS to improve the suspension performance. Experiments are performed to evaluate the SAVGS practical feasibility, the performance improvement, the accuracy of the nonlinear model and the controller’s robustness.
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series Active Variable geometry suspension application to comfort enhancement
Control Engineering Practice, 2017Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:Abstract This paper explores the potential of the Series Active Variable Geometry Suspension (SAVGS) for comfort and road holding enhancement. The SAVGS concept introduces significant nonlinearities associated with the rotation of the mechanical link that connects the chassis to the spring-damper unit. Although conventional linearization procedures implemented in multi-body software packages can deal with this configuration, they produce linear models of reduced applicability. To overcome this limitation, an alternative linearization approach based on energy conservation principles is proposed and successfully applied to one corner of the car, thus enabling the use of linear robust control techniques. An H ∞ controller is synthesized for this simplified quarter-car linear model and tuned based on the singular value decomposition of the system's transfer matrix. The proposed control is thoroughly tested with one-corner and full-vehicle nonlinear multi-body models. In the SAVGS setup, the actuator appears in series with the passive spring-damper and therefore it would typically be categorized as a low bandwidth or slow Active suspension. However, results presented in this paper for an SAVGS-retrofitted Grand Tourer show that this technology has the potential to also improve the high frequency suspension functions such as comfort and road holding.
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series Active Variable geometry suspension application to chassis attitude control
IEEE-ASME Transactions on Mechatronics, 2016Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:This paper explores the application of the recently introduced series Active Variable geometry suspension (SAVGS) to the control of chassis attitude motions and the directional response of cars. A codesign methodology, involving a component dimensioning framework and a multiobjective control scheme, is developed to maximize the SAVGS control capabilities, while respecting vehicle and actuator design constraints. The dimensioning framework comprises: a steady-state mathematical model based on the principle of virtual work; a parameter sensitivity analysis that sheds light on the dependencies that exist between the properties of the passive suspension, the SAVGS, and the chassis; and an algorithm to size the main SAVGS components for any given vehicle and steady-state performance objectives. The general multiobjective control scheme is presented for general application, and the particular case of combined chassis attitude control and overturning couple distribution control is developed in detail. The proposed scheme is subsequently applied to a high-performance sports car and a fully laden SUV, and tested under a wide range of operating conditions through the simulation of standard open-loop maneuvers. Results demonstrate the SAVGS potential to favorably regulate the attitude motions and directional response in both vehicle classes.
Carlos Arana - One of the best experts on this subject based on the ideXlab platform.
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quarter car experimental study for series Active Variable geometry suspension
IEEE Transactions on Control Systems and Technology, 2019Co-Authors: Min Yu, Simos A. Evangelou, Carlos Arana, Daniele DiniAbstract:In this paper, the recently introduced series Active Variable geometry suspension (SAVGS) for road vehicles is experimentally studied. A realistic quarter-car test rig equipped with double-wishbone suspension is designed and built to mimic an actual grand tourer real axle, with a single-link variant of the SAVGS and a road excitation mechanism implemented. A linear equivalent modeling method is adopted to synthesize an H-infinity control scheme for the SAVGS, with the geometric nonlinearity compensated. Simulations with a theoretical nonlinear quarter-car indicate the SAVGS potential to enhance suspension performance, in terms of ride comfort and road holding. Practical features in the test rig are further considered and included in the nonlinear model to compensate the difference between the theoretical and testing behaviors. Experiments with a sinusoidal road, a smoothed bump and hole, and a random road are performed to evaluate the SAVGS practical feasibility and performance improvement, the accuracy of the model, and the robustness of the control schemes. Compared with the conventional passive suspension, ride comfort improvements of up to 41% without any deterioration of the suspension deflection are demonstrated, while the SAVGS actuator power is kept very low, at levels below 500 W.
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series Active Variable geometry suspension application to comfort enhancement
Control Engineering Practice, 2017Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:Abstract This paper explores the potential of the Series Active Variable Geometry Suspension (SAVGS) for comfort and road holding enhancement. The SAVGS concept introduces significant nonlinearities associated with the rotation of the mechanical link that connects the chassis to the spring-damper unit. Although conventional linearization procedures implemented in multi-body software packages can deal with this configuration, they produce linear models of reduced applicability. To overcome this limitation, an alternative linearization approach based on energy conservation principles is proposed and successfully applied to one corner of the car, thus enabling the use of linear robust control techniques. An H ∞ controller is synthesized for this simplified quarter-car linear model and tuned based on the singular value decomposition of the system's transfer matrix. The proposed control is thoroughly tested with one-corner and full-vehicle nonlinear multi-body models. In the SAVGS setup, the actuator appears in series with the passive spring-damper and therefore it would typically be categorized as a low bandwidth or slow Active suspension. However, results presented in this paper for an SAVGS-retrofitted Grand Tourer show that this technology has the potential to also improve the high frequency suspension functions such as comfort and road holding.
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series Active Variable geometry suspension application to chassis attitude control
IEEE-ASME Transactions on Mechatronics, 2016Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:This paper explores the application of the recently introduced series Active Variable geometry suspension (SAVGS) to the control of chassis attitude motions and the directional response of cars. A codesign methodology, involving a component dimensioning framework and a multiobjective control scheme, is developed to maximize the SAVGS control capabilities, while respecting vehicle and actuator design constraints. The dimensioning framework comprises: a steady-state mathematical model based on the principle of virtual work; a parameter sensitivity analysis that sheds light on the dependencies that exist between the properties of the passive suspension, the SAVGS, and the chassis; and an algorithm to size the main SAVGS components for any given vehicle and steady-state performance objectives. The general multiobjective control scheme is presented for general application, and the particular case of combined chassis attitude control and overturning couple distribution control is developed in detail. The proposed scheme is subsequently applied to a high-performance sports car and a fully laden SUV, and tested under a wide range of operating conditions through the simulation of standard open-loop maneuvers. Results demonstrate the SAVGS potential to favorably regulate the attitude motions and directional response in both vehicle classes.
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Series Active Variable Geometry Suspension for Road Vehicles
IEEE ASME Transactions on Mechatronics, 2015Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:A new family of electro-mechanical Active suspensions that offers significant advantages with respect to passive and semiActive suspensions, while at the same time avoiding the main disadvantages of alternative Active solutions, is presented in this paper. The series Active Variable geometry suspension takes a conventional independent passive or semiActive suspension as its starting point, and improves its behavior by Actively controlling the suspension geometry with an electro-mechanical actuator. The advantages of this type of suspension are discussed and its simplest variant is studied in detail. Insight on the design process, as well as on the actuator modeling and selection is provided. Moreover, a control system for pitch attitude control of the chassis is presented. Simulation results obtained with a high-fidelity, full-vehicle, nonlinear model of a high-performance sports car that includes actuator dynamics and saturation limits are shown to confirm the potential of the proposed system.
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pitch angle reduction for cars under acceleration and braking by Active Variable geometry suspension
Conference on Decision and Control, 2012Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:This paper proposes a new concept of car Active suspension that shows significant advantages with respect to previous systems. The Active Variable Geometry Suspension (AVGS) is based on a passive suspension, in which an extra link/chain of linkages is connected in series to the spring damper unit. One servo-motor per wheel is used to continuously and independently modify the position of the links in the mechanism in each quarter of the car, thus allowing to effectively control body motions. In order to demonstrate the potential performance of the concept, a state-of-the art non-linear full car model, which includes actuator dynamics and an adaptive pitch control system, has been developed. Results corresponding to acceleration and emergency braking maneuvers for a generic high-performance sports car are presented and show the effectiveness of the proposed suspension to control the pitch angle of the vehicle.
Simos A. Evangelou - One of the best experts on this subject based on the ideXlab platform.
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robust control for a full car prototype of series Active Variable geometry suspension
Conference on Decision and Control, 2019Co-Authors: Min Yu, Simos A. Evangelou, Cheng Cheng, Daniele DiniAbstract:The Series Active Variable Geometry Suspension (SAVGS) which has been recently proposed shows promising potential in terms of suspension performance enhancement, limited power consumption and so on. In this paper, the control aspects of a full-car prototype with the front axle retrofitted by the SAVGS, which is developed to validate the practical feasibility of the novel mechatronic suspension, are addressed. Two 12 V dc batteries and one DC/AC inverter constitute an independent power source that supplies the overall embedded mechatronic system, with two AC rotary servo motors driving the single links (in the SAVGS) at two front corners, respectively. A robust control scheme, with an outer-loop H-infinity control and an inner-loop actuator velocity tracking control, is synthesized to enhance the vehicle ride comfort and road holding performance. Numerical simulations of the full-car prototype, with the typical road events of a 2 Hz harmonic road, and a speed hump tested, are performed. The results of numerical simulations indicate the potential suspension performance improvement contributed by the SAVGS and the power usage in the batteries, which will be compared in the future with the upcoming experimental testing results of the prototype on-road driving.
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quarter car experimental study for series Active Variable geometry suspension
IEEE Transactions on Control Systems and Technology, 2019Co-Authors: Min Yu, Simos A. Evangelou, Carlos Arana, Daniele DiniAbstract:In this paper, the recently introduced series Active Variable geometry suspension (SAVGS) for road vehicles is experimentally studied. A realistic quarter-car test rig equipped with double-wishbone suspension is designed and built to mimic an actual grand tourer real axle, with a single-link variant of the SAVGS and a road excitation mechanism implemented. A linear equivalent modeling method is adopted to synthesize an H-infinity control scheme for the SAVGS, with the geometric nonlinearity compensated. Simulations with a theoretical nonlinear quarter-car indicate the SAVGS potential to enhance suspension performance, in terms of ride comfort and road holding. Practical features in the test rig are further considered and included in the nonlinear model to compensate the difference between the theoretical and testing behaviors. Experiments with a sinusoidal road, a smoothed bump and hole, and a random road are performed to evaluate the SAVGS practical feasibility and performance improvement, the accuracy of the model, and the robustness of the control schemes. Compared with the conventional passive suspension, ride comfort improvements of up to 41% without any deterioration of the suspension deflection are demonstrated, while the SAVGS actuator power is kept very low, at levels below 500 W.
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model identification and control for a quarter car test rig of series Active Variable geometry suspension
IFAC-PapersOnLine, 2017Co-Authors: Min Yu, Simos A. Evangelou, Daniele DiniAbstract:Abstract In this paper, a quarter car test rig is utilized to perform an experimental study of the single-link variant of the Series Active Variable Geometry Suspension (SAVGS). A nonlinear model of the test rig is identified with the use of a theoretical quarter car model and the rig’s experimental frequency response. A linear equivalent modeling method that compensates the geometric nonlinearity is also adopted to synthesize an H-infinity control scheme. The controller Actively adjusts the single-link velocity in the SAVGS to improve the suspension performance. Experiments are performed to evaluate the SAVGS practical feasibility, the performance improvement, the accuracy of the nonlinear model and the controller’s robustness.
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series Active Variable geometry suspension application to comfort enhancement
Control Engineering Practice, 2017Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:Abstract This paper explores the potential of the Series Active Variable Geometry Suspension (SAVGS) for comfort and road holding enhancement. The SAVGS concept introduces significant nonlinearities associated with the rotation of the mechanical link that connects the chassis to the spring-damper unit. Although conventional linearization procedures implemented in multi-body software packages can deal with this configuration, they produce linear models of reduced applicability. To overcome this limitation, an alternative linearization approach based on energy conservation principles is proposed and successfully applied to one corner of the car, thus enabling the use of linear robust control techniques. An H ∞ controller is synthesized for this simplified quarter-car linear model and tuned based on the singular value decomposition of the system's transfer matrix. The proposed control is thoroughly tested with one-corner and full-vehicle nonlinear multi-body models. In the SAVGS setup, the actuator appears in series with the passive spring-damper and therefore it would typically be categorized as a low bandwidth or slow Active suspension. However, results presented in this paper for an SAVGS-retrofitted Grand Tourer show that this technology has the potential to also improve the high frequency suspension functions such as comfort and road holding.
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series Active Variable geometry suspension application to chassis attitude control
IEEE-ASME Transactions on Mechatronics, 2016Co-Authors: Carlos Arana, Simos A. Evangelou, Daniele DiniAbstract:This paper explores the application of the recently introduced series Active Variable geometry suspension (SAVGS) to the control of chassis attitude motions and the directional response of cars. A codesign methodology, involving a component dimensioning framework and a multiobjective control scheme, is developed to maximize the SAVGS control capabilities, while respecting vehicle and actuator design constraints. The dimensioning framework comprises: a steady-state mathematical model based on the principle of virtual work; a parameter sensitivity analysis that sheds light on the dependencies that exist between the properties of the passive suspension, the SAVGS, and the chassis; and an algorithm to size the main SAVGS components for any given vehicle and steady-state performance objectives. The general multiobjective control scheme is presented for general application, and the particular case of combined chassis attitude control and overturning couple distribution control is developed in detail. The proposed scheme is subsequently applied to a high-performance sports car and a fully laden SUV, and tested under a wide range of operating conditions through the simulation of standard open-loop maneuvers. Results demonstrate the SAVGS potential to favorably regulate the attitude motions and directional response in both vehicle classes.
Matthew R Williams - One of the best experts on this subject based on the ideXlab platform.
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impact on gait biomechanics of using an Active Variable impedance prosthetic knee
Journal of Neuroengineering and Rehabilitation, 2016Co-Authors: Matthew R Williams, Susan E Dandrea, Hugh M HerrAbstract:An above knee amputation can have a significant impact on gait, with substantial deviations in inter-leg symmetry, step length, hip exertion and upper body involvement even when using a current clinical standard of care prosthesis. These differences can produce gait that is less efficient and less comfortable, resulting in slower and shorter distance walking, particularly with long term use. A robotic Variable impedance prosthetic knee (VI Knee) was tested with five individuals (N = 5) with unilateral amputation above the knee at fixed speeds both above and below their normal walking speed. Subject gait was measured as they walked along an instrumented walkway via optical motion capture and force plates in the floor. Each subject’s gait while using the VI Knee was compared to that while using their standard of care knee (OttoBock C-Leg). Significant differences (p < 0.05) in walking between the standard of care and Variable impedance devices were seen in step length and hip range of motion symmetries, hip extension moment, knee power and torso lean angle. While using the VI Knee, several subjects demonstrated statistically significant improvements in gait, particularly in increased hip range of motion symmetry between affected and intact sides, greater prosthesis knee power and in reducing upper body involvement in the walking task by decreasing forward and affected side lean and reducing the pelvis-torso twist coupling. These changes to torso posture during gait also resulted in increased terminal stance hip flexion moment across subjects. Detriments to gait were also observed in that some subjects exhibited decreased step length symmetry while using the VI Knee compared to the C-Leg. The knee tested represents the potential to improve gait biomechanics and reduce upper body involvement in persons with above knee amputation compared to current standard of care devices. While using the VI Knee, subjects demonstrated statistically significant improvements in several aspects of gait though some were worsened while using the device. It is possible that these negative effects may be mitigated through longer term training and experience with the VI Knee. Given the demonstrated benefits and the potential to reduce or eliminate detriments through training, using a powered device like the VI Knee, particularly over an extended period of time, may help to improve walking performance and comfort.
Nong Zhang - One of the best experts on this subject based on the ideXlab platform.
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semi Active Variable stiffness vibration control of vehicle seat suspension using an mr elastomer isolator
Smart Materials and Structures, 2011Co-Authors: Haiping Du, Weihua Li, Nong ZhangAbstract:This paper presents a study on continuously Variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal controller for an Active isolator. The desired control force generated by this Active isolator is then emulated by the MRE isolator through its continuously Variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control.
