| 1. |
- Albinsson, Anton, 1989, et al.
(författare)
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Scaling tire models to different road surfaces using an external IMU and K&C measurements
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Accurate simulation models are required for virtual verification of vehicle dynamics and chassis control functions. The force and moment characteristics of tires depend on the road surface. To achieve good simulation and testing correlation accuracy, an accurate tire model that is representative for the actual road surface is required. This study investigates a cost-efficient method to scale Pacejka 2002 models, based on flat belt measurements, to a real road surface using simple instrumentation and static measurements of a test vehicle. The feasibility of the method is illustrated using measurements, where the propagation of measurement error to model error is investigated.
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| 2. |
- Albinsson, Anton, 1989, et al.
(författare)
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Validation of vehicle-based tyre testing methods
- 2019
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 233:1, s. 18-27
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Tidskriftsartikel (refereegranskat)abstract
- The development process for passenger cars is both time- and resource-consuming. Full vehicle testing is an extensive part of the development process that consumes large amount of resources, especially within the field of vehicle dynamics and active safety. By replacing physical testing with complete vehicle simulations, both the development time and cost can potentially be reduced. This requires accurate simulation models that represent the real vehicle. One major chal- lenge with full vehicle simulation models is the representation of tyres in terms of force and moment generation. The force and moment generation of the tyres is affected by both operating conditions and road surface. Vehicle-based tyre testing offers a fast and efficient way to rescale force and moment tyre models to different road surfaces, in this study the Pacejka 2002 model. The resulting tyre model is sensitive to both the operating conditions during testing and the road surface used. This study investigates the influence of the slip angle sweep rate and road surface on the lateral tyre force characteristics of the fitted tyre model. Tyre models fitted to different manoeuvres are compared and the influence on the full vehicle behaviour is investigated in IPG Carmaker. The results show that by using the wrong road surface, the resulting tyre model can end up outside the tolerances specified by the ISO standard for vehicle simulation model verifi- cation in steady-state cornering. The use of Pacejka 2002 models parameterized in a steady-state manoeuvre to simulate the vehicle behaviour in sine-with-dwell manoeuvres is also discussed.
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| 3. |
- Chen, Weitao, 1989, et al.
(författare)
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An Architecture of Hardware and Driver in the Loop Simulation for Electric Power Assisted Steering System
- 2020
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Ingår i: Lecture Notes in Mechanical Engineering. - Cham : Springer International Publishing. - 2195-4356 .- 2195-4364. - 9783030380762
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Konferensbidrag (refereegranskat)abstract
- This paper introduces an architecture for virtual development of electric power assisted steering (EPAS) system, which is implemented at Volvo Cars. The architecture involves an EPAS power pack rig and driver in the loop, so engineers can test both the ECU software and electric motor on a virtual prototype vehicle. Eective results are shown for tests in low-mid frequency and at mid-high vehicle speed. Currently, the high frequency and low speed test is still challenging due to vibration and instability, which should be addressed by the control improvement.
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| 4. |
- Chen, Weitao, 1989, et al.
(författare)
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Design of Interface in Co-simulation for Electric Power Assisted Steering System Development
- 2018
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Ingår i: Proceedings of the 14th International Symposium on Advanced Vehicle Control.
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Konferensbidrag (refereegranskat)abstract
- Interface and causality have important effects on the co-simulation used in vehicle system development. In this paper we analyzed these effects by modeling a co-simulated dual mass-spring-damper system as a sampled-data system. By stability and frequency domain analysis we find that the co-simulation interface needs be designed where the coupling interface is less stiff and the force variable should be applied in the direction of larger mass, natural frequency and damping ratio. The analytical results have been verified through two test cases of co-simulation in electric power assisted steering (EPAS) system development: a multi-rate offline co-simulation and a hardware-in-loop (HIL) simulation. Both test cases showed more consistent and stable results using the suggested interface design.
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| 5. |
- Chen, Weitao, 1989, et al.
(författare)
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Explicit parallel co-simulation approach: analysis and improved coupling method based on H-infinity synthesis
- 2021
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Ingår i: Multibody System Dynamics. - : Springer Science and Business Media LLC. - 1573-272X .- 1384-5640. ; 52:3, s. 255-279
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Tidskriftsartikel (refereegranskat)abstract
- Co-simulation is widely used in the industry for the simulation of multidomain systems. Because the coupling variables cannot be communicated continuously, the co-simulation results can be unstable and inaccurate, especially when an explicit parallel approach is applied. To address this issue, new coupling methods to improve the stability and accuracy have been developed in recent years. However, the assessment of their performance is sometimes not straightforward or is even impossible owing to the case-dependent effect. The selection of the coupling method and its tuning cannot be performed before running the co-simulation, especially with a time-varying system. In this work, the co-simulation system is analyzed in the frequency domain as a sampled-data interconnection. Then a new coupling method based on the H-infinity synthesis is developed. The method intends to reconstruct the coupling variable by adding a compensator and smoother at the interface and to minimize the error from the sample-hold process. A convergence analysis in the frequency domain shows that the coupling error can be reduced in a wide frequency range, which implies good robustness. The new method is verified using two co-simulation cases. The first case is a dual mass–spring–damper system with random parameters and the second case is a co-simulation of a multibody dynamic (MBD) vehicle model and an electric power-assisted steering (EPAS) system model. Experimental results show that the method can improve the stability and accuracy, which enables a larger communication step to speed up the explicit parallel co-simulation.
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| 6. |
- Chen, Weitao, 1989, et al.
(författare)
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Integration and Analysis of EPAS and Chassis System in FMI-based co-simulation
- 2019
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Ingår i: Proceedings of the 13th International Modelica Conference. - : Linköing University Electronic Press. - 9789176851227 ; :157, s. 717-724
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Konferensbidrag (refereegranskat)abstract
- The vehicle steering characteristics and active functions can be virtually developed with a high-fidelity electric power assisted steering (EPAS) model and a multibody chassis model. The simulation of the EPAS model requires small integration step due to high stiffness and interfacing with the controller. The multibody chassis model is computationally heavy for each integration step due to calculation of large matrices. A mono-simulation based on a single solver is not efficient for this case. Instead a co-simulation (solver coupling) approach has been used to overcome the drawbacks.In this paper the EPAS system and chassis system are modeled in Dymola and further exported as separate functional mockup units (FMUs) and integrated with the control algorithms in Matlab. A co-simulation based on the explicit parallel calculation scheme (Jacobi scheme) has been used. A huge simulation speed-up has shown the potential and effectiveness of the approach. To understand its accuracy and tolerance, analysis on the numerical error and dynamics of the coupled-system are given.
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| 7. |
- Chugh, Tushar, 1989, et al.
(författare)
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Comparison of Steering Feel Control Strategies in Electric Power Assisted Steering
- 2018
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Ingår i: International Symposium on Advanced Vehicle Control.
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Konferensbidrag (refereegranskat)abstract
- This paper presents an objective comparison of two closed-loop steering feel control concepts in an electric power assisted steering (EPAS) system. The closed-loop methods, torque- and position-control, aim to compensate the EPAS motor inertia in an effective manner as compared to the open loop (feed-forward) solution. For a given steering feel reference, the feedback controllers are developed in a sequential manner ensuring coupled stability. Linear system theory is used for the analysis. For a comparable reference tracking and stability margin, higher haptic controller bandwidth is achieved in torque-control. The position controller stability and performance are limited due to feedback control filtering and high system inertia (from EPAS motor and driver arms), which further makes it more sensitive towards muscle co-contraction. Moreover, torque-control offers better road disturbance attenuation for low and high frequency spectrum, whereas position-control is better for mid-frequency range.
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| 8. |
- Chugh, Tushar, 1989, et al.
(författare)
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Design and control of model based steering feel reference in an electric power assisted steering system
- 2018
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Ingår i: The Dynamics of Vehicles on Roads and Tracks. ; 1, s. 43-49
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Konferensbidrag (refereegranskat)abstract
- Electric Power Assisted Steering (EPAS) system is a current state of the art technology for providing the steering torque support. The interaction of the steering system with the driver is principally governed by the EPAS control method. This paper proposes a control concept for designing the steering feel with a model based approach. The reference steering feel is defined in virtual dynamics for tracking. The layout of the reference model and the control architecture is discussed at first and then the decoupling of EPAS motor dynamics using a feedback control is shown. An example of how a change in steering feel reference (as desired by the driver) creates a change in steering feedback is further exhibited. The ultimate goal is to provide the driver with a tunable steering feel. For this, the verification is performed in simulation environment.
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| 9. |
- Ran, Shenhai, 1985, et al.
(författare)
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Tyre measurements and modelling for parking manoeuvres
- 2017
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Ingår i: Dynamics of Vehicles on Roads and Tracks. - : CRC Press. ; 1
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Konferensbidrag (refereegranskat)abstract
- In order to develop and verify the steering system, especially during parking manoeuvres with numerical methods, a tyre model that generates accurate lateral force and self-aligning moment is definitely essential. This paper first reviews the tyre parking measurements from the recently developed tyre test rig at Camber Ridge. After that, a new method is introduced to describe the tyre force and moment for parking as an extension of the combined slip Magic Formula. The turn slip effect is implicitly incorporated by shifting the acting point with an effective width and length of the contact patch. The validations between the measurements and simulations suggest that proposed method is promising for improving the correlation of measured tyre force and moment generation for parking manoeuvres over the standard Magic Formula tyre model.
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