A novel miniature attitude measurement system for climbing and walking robots

A novel design of miniature attitude measurement system for climbing and walking robots is presented. By integrating three-dimensional magnetometers and three microelectromechanical accelerometers, the system provides high-frequency position and attitude data. And it takes advantages of the solid-state configuration, small size, light weight, high reliability, low power consumption, rapid startup and relatively low cost. It can be used to test the transient attitude of the moving body such as robots. The three-axis accelerometers detect the three orthogonal components of the gravity, by which tilt of the robots including pitch and roll can be derived. Otherwise a three-axis magnetometer which are also assembled as an orthogonal placement to measure the three components of the Earth's magnetic field. The calculation and simulations indicate that the formalism proposed in this paper is able to reach an excellent long-term performance. Even if there is various error sources existing in the measurement, the non-orthogonal assembling error is the most dominating. We analyze the representative features of this error, establish a mathematic model for it, and successfully compensate this error via arithmetic. Finally, real experiments performed with a mobile robot are presented and analyzed. The results of the test indicate that the system can measure the freewill attitude in three-dimensional space. It is expected that this system will be adopted in many fields.