A Very Small Low Cost Inertial Measurement Unit (IMU) for Robotic Applications

摘要

To optimize path planning and control of legged robots a measurement unit similar to the human balancing sensor is required to determine position and orientation. There are three kinds of sensors used to achieve this target: Acceleration sensors to detect gravity acceleration, gyros for the rotational rates and magnetic field sensors to build the electronic compass. To minimize alignment errors of the sensors a simple cubic arrangement was used. This article deals with the mechanical and electronical construction of the whole IMU, the selection of the suitable sensors and their calibration. Orientation is calculated by a simple nonlinear observer that is also able to compensate for drift of the gyros and misalignment. Further the profits of the MPC555 as microcontroller and the use of the RTOS-UH as system on chip are discussed. These decisions made it possible to construct the inertial measurement unit very compact.