State estimation on flexible robots using accelerometers and angular rate sensors

Fast moving robots with elastic joints and/or elastic links require vibration suppression to achieve accuracy. We introduce a two-degrees-of-freedom control scheme (2DoF) consisting of a feedforward component based on the flatness approach and a classic feedback component, such as a PD motor joint control with additional link position error or joint torque error feedback. Such a control scheme requires knowledge of the full system state. We present an approach for state estimation using angular rate-and acceleration-sensors-mounted on each robot link-that can be used for any kind of elastic robot manipulator. We validate our theory by measuring a very fast trajectory and the influence of an external disturbance on an articulated robot with two flexible links and three joints.