Yaw moment control using an active differential and Electronic Stability Control system (ESC)
Examensarbete för masterexamen
Automotive engineering (MPAUT), MSc
This thesis aims to compare the potential in handling and performance between a brake based Electronic Stability Control system (ESC) with a system that integrates an active differential with ESC. Two control strategies that integrate an active differential and ESC are presented for two types of active differentials. The differentials are the Electronic Limited Slip Differential (eLSD) and the Direction Sensitive Locking Differential (DSLD). The control strategies are developed and the results are evaluated using a simulation model that is implemented in Simulink. They tested for one driving case, the open loop sine with dwell maneuver. The different solutions are evaluated mainly with regard to three criteria that are specified in the American National Highway Traffic Safety Administration FMVSS 126 law requirement (NTHSA, 2007). They are also evaluated with respect to the yaw rate vs. steering wheel angle response, vehicle speed during the maneuver and vehicle trajectory. All tests were performed without any time delays simulated for any actuator. The results show only a small difference between a normal ESC and the integrated solutions. The integrated system with an eLSD however does perform better than ESC overall but by a small margin. Because of the small difference in results from the first simulations time delays are implemented for a second round of simulations that only compare the best integrated solution (ESC + eLSD) to only ESC. This is done to evaluate how much of an effect the time delays have on the end results. After the second round of simulations the results do indeed differ more in favor of the integrated system with the eLSD compared to only ESC. The yaw rate respond better to steering wheel inputs with smaller overshoots and more speed is conserved through the maneuver. This shows that the simulation model might not be complete enough to evaluate the performance difference between those systems and implementing time delays more extensively for all actuators is a recommendation for future work.
Transport , Farkostteknik , Transport , Vehicle Engineering