Hybrid Genetic Algorithm and Kalman Filter Approach to Estimate the Clamping Force of Electro-Mechanical Brake

In thispaper, a hybrid genetic algorithm (GA) and Kalman filter approach to combining motor encoder and current sensor models is presented to accurate estimate the clamping force of an electro-mechanical brake (EMB). Elimination of the clamping force sensor and measurement cables results in lower cost and increased reliability of an EMB system, including its electric motor.A Kalman filter is a special kind of observer that provides optimal filtering of the measurement noise and inside the system if the covariances of these noises are known. The proposed combined estimator is based on Kalman filter optimized by GA in which the motor encoder is used in a dynamic stiffness model and the motor current sensor is used to give measurement updates in a torque balance model. A real-coded GA is used to optimize the noise matrices and improve the performance of the Kalman filter. Experimental results show that, by using the proposed estimator, the virtual clamping force sensor can handle highly dynamic situations, making it suitable for possible use in sensorless fault-tolerant control. It is shown that the proposed combined estimator improves the root mean square error (RMSE) performance. The developed estimator can be used in real vehicle environments because it can adapt to parameter variations

Multi-channel plastic-scintillator-based detection system for monitoring tritium in air

To overcome the limitations of the ionization chamber-based tritium monitor, a design for a multichannel plastic scintillator-based detection chamber for monitoring tritium in air is proposed. The performance of the chamber was characterized by Monte Carlo-based calculations with various design parameters such as thickness of the plastic scintillator (t) and number of channels (n). We considered the volume and detection efficiency of the chamber to evaluate the performance of the detector. The expected counting rate curve was in good agreement with the expected simplified physical model. The minimum detectable activity (MDA) was shown at t = 0.5 mm and n = 48 and estimated to be 29.9 kBq/m3. Compared with the experimentally estimated MDA, the relative difference was approximately 24%. However, this difference is understandable considering the different lower level of discrimination and light loss during transportation assumed in the model. The proposed tritium detection chamber is expected to be useful for environmental monitoring at some level as well as for monitoring of tritium leaks from fusion or CANada Deuterium Uranium (CANDU)-type reactors