Adaptive optimal slip ratio estimator for effective braking on a non-uniform condition road

In this paper, an adaptive algorithm is developed which senses the road condition change and estimates a (time-varying) optimal braking slip ratio. This is conducted by two on-line simultaneously operating tire-road friction-curve slope calculators: one based on the accelerometer output and the other based on the wheel speed. The required vehicle speed is estimated using a robust sliding-mode observer. Enforcement of the online optimal braking reference is left to an adaptive sliding mode controller to cope with the system strong nonlinearity, time dependency and the speed and friction-coefficient estimation errors. The algorithm is applied to a half model car and the braking performance is examined. The results indicate that the proposed algorithm substantially reduces the stopping time and distance. The performance of the algorithm is verified using different vehicle initial speeds and especially non-uniform road condition where 8% improvement versus the nonadaptive optimal slip ratio algorithm is recorded

On the accuracy of detailed model inductance matrix estimation for air core winding

Researchers have used various methods to determine the parameters of transformer- equivalent circuits in transient studies. But most of these previous algorithms had difficulty finding the equivalent circuit parameters in a bigger model. This paper presents a new method to extract the inductance matrix of a detailed model for an air core winding for transient studies using frequency-response measurement data. This matrix can be determined with acceptable accuracy by using the proposed method. The biggest advantage of the proposed method is a reduction in the search space, and thus, speedier problemsolving. Simulations showed that the use of the proposed method leads to better behavioural quality of a transformer winding. The simulation results of the previous and proposed methods were compared with the help of a 20/0.4 kV, 1600 kVA transformer. This comparison showed the accuracy and superiority of the proposed method

On the accuracy of detailed model inductance matrix estimation for air core winding

Researchers have used various methods to determine the parameters of transformer- equivalent circuits in transient studies. But most of these previous algorithms had difficulty finding the equivalent circuit parameters in a bigger model. This paper presents a new method to extract the inductance matrix of a detailed model for an air core winding for transient studies using frequency-response measurement data. This matrix can be determined with acceptable accuracy by using the proposed method. The biggest advantage of the proposed method is a reduction in the search space, and thus, speedier problemsolving. Simulations showed that the use of the proposed method leads to better behavioural quality of a transformer winding. The simulation results of the previous and proposed methods were compared with the help of a 20/0.4 kV, 1600 kVA transformer. This comparison showed the accuracy and superiority of the proposed method