Enhancing MPS Signal by Bipolar Pulse Excitation and Interference of Reflection Wave

To enhance the signal intensity of magnetostrictive position sensor (MPS), a new method of bipolar pulse excitation (BPE), and a new structure of single-end damper (SED) are proposed in this paper. Two torsion strain waves, named as W1 and W2 waves, are generated by the BPE, and the W1 wave is reflected (changed into RW1) by the SED. Based on the principle of wave superposition, the interference between RW1 and W2 is realized by adjusting the structure parameters of the sensor. Therefore, the MPS signal is strengthened 1.8 times approximately as well as the measuring range. The notable difference between the new strategy and the conventional one lies in the reflection wave. In conventional MPS, the smaller the reflection wave is, the better the signal will be. However, the reflection wave should be as strong as possible in the new strategy. After the explanation of BPE and SED, a new model is presented. The validity and feasibility of the proposed strategy are verified by experiments. Finally, the characteristics of BPE and SED, such as the measured object, the polar of excitation pulse, and the limit of signal, are discussed in detail. Research results indicate that the proposed BPE method and SED structure are innovative development to conventional MPS, and are of great practical value.