Six-axis electrostatic accelerometer

Abstract

A novel six DOF electrostatic accelerometer is theoretically developed. A special detection system and a pure electrostatic suspension system are created, which make it possible to measure six DOF acceleration with one proofmass. Author realizes that the two main barriers in development of multi-DOF accelerometers are suspension system and the decoupling technology. These problems are also theoretically explained by the dynamics equations of a six DOF accelerometer. A single hollow cubic proofmass and twenty-four pairs of plates are employed in this new device. A special combination of these twenty-four pairs of plates forms six Wheatstone bridges which can serve as both detection system and suspension system. The new detection system can sense six DOF accelerations with only one proofmass without any coupling effects. The pure electrostatic suspension system can levitate the proofmass without any electrical and mechanical linkages, which makes it possible to design highly accurate accelerometers. Both detection system and suspension system are carefully modeled. Immunity of this new sensor to cross-coupling effects in traditional accelerometers are proved. Transfer functions of six DOF accelerometer system and several important constants are given. A control system based on modem state space method is investigated and simulated by Matlab SIMULINK. The author believes that this new six DOF electrostatic accelerometer will fill the vacancy of this area and will find many applications in space environment, robotics, bioengineering, automobile industry and new generation navigation system with GPS system.