Braking control performances of a disk-type magneto-rheological brake via hardware-in-the-loop simulation

The aim of this work is to develop a magneto-rheological brake control system based on the hardware-in-the-loop simulation to analyze braking performances such as time response characteristics of the desired torque with the input currents. As a first step, a mathematical model of the braking torque is formulated and the optimized structure parameters of magneto-rheological brake are determined. Subsequently, the hardware-in-the-loop simulation system associated with the braking bench is established in which the software controlling the braking performances is implemented by a proportional–integral–derivative controller. Several tests to evaluate control performances of magneto-rheological brake are undertaken focusing on the decrement and increment by the input current. In addition, a quarter vehicle model equipped with the antilock brake system is tested through the hardware-in-the-loop simulation. It is shown that the antilock brake system integrated with magneto-rheological brake quickly tracks the desired slip rate resulting in stable performances.

Research on HILS Technology Applied on Aircraft Electric Braking System

On the basis of analyzing the real-time feature of hardware-in-the-loop simulation of aircraft braking system, a new simulation method based on MATLAB/RTW (Real-Time Workshop) and DSP is introduced. The purpose of this research is to develop a digital control unit with antilock brake system control algorithm for aircraft braking system using HILS. DSP is used as simulator. Using this method, a detailed mathematical modeling of system is proposed first. Studies on reducing sampling time with model simplification and modeling for applying to I/O interface of DSP and HILS are conducted. Compared with other methods, this method is low cost and convenient to implement. By using these methods, we can complete HIL simulation of aircraft braking under various experimental conditions, modify its control laws, and test its braking performance. The results have demonstrated that this platform has high reliability. The algorithm is verified by real-time closed loop test with HILS system and the results are presented.

Peak Friction Prediction Model Based on Surface Texture Characteristics

This paper proposes a new model for predicting the speed gradient of peak friction values on asphalt pavements on the basis of surface characteristics. The innovative feature of the proposed model is the reliable estimation of peak friction values experienced by vehicles equipped with an antilock brake system at a certain vehicle speed. To define the experimental model, several types of dense asphalt concrete surface layers with various surface characteristics were analyzed by in situ tests. Friction was measured with the Skiddometer BV11 and the British pendulum tester, and texture properties were measured with a laser profilometer. The Rado model was used to predict peak friction values at three vehicle speeds, and these data were used to determine the gradient of peak friction values for each pavement section. The spectral analysis of pavement profile data was used to define a texture parameter negatively correlated with peak friction values; this parameter was introduced in a new formulation of the speed number Sp* that was a measure of the influence of pavement macrotexture on peak friction values. The speed number Sp* was used in the new exponential model proposed for defining the gradient of peak friction values. The results show that the model is highly reliable; because the model allows identification of texture characteristics to be modified to optimize peak friction values, it is particularly useful for optimization of the mix design and maintenance of pavement surfaces.

Consequences of Electrical Arc on Automotive Connector during Extraction Phase

Comfort, safety, communication, control with assistance (antilock brake system, seat heating, multi-media, etc...) and safeguarding the environment are many factors which are included in the new generation of vehicles. The increase in the number of electronic and electric system leads to a high level of vehicle control. To answer this high electric power demand, it will be necessary to triple the voltage of the batteries (from 14 to 42 Volts). The objective of this work is to study the arc phenomenon which can occur in an accidental way during the use of a high electric power and particularly during the extraction phase of the male part from the female part of the automotive connector. It was observed that this can be characterized by both its energy and by its temperature. The amplification of the contact current from 14 to 42 VDC considerably increases arc damage.