Hardware-in-the-Loop-Environment for multi-directional axle testing and design of suspension systems
Final Report Abstract
In a HiL simulation, the overall system to be investigated is divided into a physical DUT (device under test) which is operated in a lab and a model of the residual subsystem which is simulated on a real-time computer. The two subsystems are coupled with each other, thus tests can be carried out without having the complete system to be actually present which is advantegeous in the development of mechatronic systems. The method is already state of the art, especially in the field of automotive ECU development. Here, signals are exchanged between the ECU and the residual system. In testing mechatronic systems, the coupling is done via forces/torques. Whereas test benches have already been developed for mechanical subcomponents of a chassis, there are no HiL test benches for complete vehicle axles. This gap should be closed within the scope of this project. As an application example, we integrated a vehicle axle with active roll stabilization into a HiL simulation. The resulting residual vehicle model consists of a two-track model with 36 states representing a good compromise between accuracy and computational efficiency. A hydraulic linear actuator was added to the passive vehicle axle for emulating an active roll stabilizer. A multi-stage procedure model for the design of HiL simulations was developed, which ensures that the resulting HiL simulation represents the desired target system (real driving tests or simulation of a highly detailed vehicle model) sufficiently accurately. The coupling (synchronization) of the real and virtual subsystems is achieved by actuators and sensors. The appropriate choice of synchronization variables is crucial to ensure that the HiL control loop is stable. As part of the project, the existing hybrid force/position control was extended to a hybrid indirect force control allowing four modes to be implemented: indirect admittance and impedance control, and direct force and position control. The control modes are selected depending on the stiffness in the respective actuator degree of freedom. The HiL simulation of the vehicle axle with active roll stabilization was extended to include active steering. For this purpose, a steering motor was installed in the test rig. This resulted in a HiL simulation in which the degrees of freedom of the hexapod were controlled with four different control modes appropriate to the requirements. The results obtained with the design steps defined in the process model show good agreement with the benchmark system, so that feasibility could be demonstrated.
Publications
- Observerbased nonlinear control strategies for Hardware-in-the-Loop simulations of multiaxial suspension test rigs. Mechatronics, (2018), Nr. 50, 212–224
Olma, S.; Kohlstedt, A.; Traphöner, P.; Jäker, K.-P.; Trächtler, A.
(See online at https://doi.org/10.1016/j.mechatronics.2017.10.007) - Hardware-in-the-Loop Simulation for a Multiaxial Suspension Test Rig with a Nonlinear Spatial Vehicle Dynamics Model. 8th IFAC Symposium on Mechatronic Systems. Vienna, 2019
Traphöner, P.; Olma, S.; Kohlstedt, A.; Fast, N.; Jäker, K.-P.; Trächtler, A.
(See online at https://doi.org/10.1016/j.ifacol.2019.11.659) - Hardware-inthe-Loop-Simulation einer Fahrzeugachse mit aktiver Wankstabilisierung mithilfe eines hydraulischen Hexapoden. VDI/VDE-Tagung MECHATRONIK. Paderborn, 2019
Traphöner, P.; Kohlstedt, A.; Olma, S.; Jäker, K.-P.; Trächtler, A.
(See online at https://doi.org/10.17619/UNIPB/1-778)
