The Development of Lead-Free Piezoelectric MEMS Triaxial Accelerometer System​for Safety Monitoring of Unmanned Vehicles​

　　Due to the rising global environmental awareness, the regulations for lead-containing products are becoming stricter, such as the EU's RoHS hazardous substances restriction regulations. In the future, lead-containing products will be gradually eliminated, and lead-free products will become the mainstream of the future market.

　　Our team established material doping technology to greatly improve the piezoelectric properties of lead-free materials, and successfully fabricated MEMS lead-free triaxial piezoelectric accelerometers. It has the advantages of small size, light weight, and heterogeneous chip integration technology and CMOS manufacturing process. Different from the previous MEMS three-axis piezoelectric accelerometers that use PZT lead-containing materials, the use of lead-free materials is the world's first development result.

　　In addition, the team applied the accelerometer system to the safety monitoring of unmanned vehicles. This system includes sensing signals from unmanned vehicles through MEMS lead-free three-axis accelerometer components, converting analog signals into digital signals through a reading circuit and ADC circuit, then processing the signals through Arduino and Raspberry Pi, and passing the calculation results through Wireless transmission to the user's personal computer, real-time display of the safety monitoring information of the unmanned vehicle through the software of the user interface, including the amplitude, frequency and the health status of the unmanned aerial vehicle, this system can help the user to know the unmanned vehicle's body in real time security situation.

The team continues to integrate the upstream "piezoelectric accelerometer production", midstream "circuit and module design" and downstream "user platform development" to independently develop a set of Internet of Things system, opening up a new world of acceleration sensors path of.

Figure 1 Flowchart of accelerometer safety monitoring system

Figure 2  Accelerometer safety monitoring system user interface