Measurement of mobile manipulator chassis pose change caused by suspension deformation and end-effector accuracy improvement based on multi-sensor fusion

Abstract

In order to expand the application of mobile manipulators in high-precision scenarios, researchers have focused on improving their accuracy. However, it is challenging to eliminate the impact of reference movement on manipulator accuracy during operation. Therefore, real-time measurement of manipulator reference and compensation of end pose are necessary. To address the inflexibility of global measurement schemes, this study proposes a method for obtaining the pose change of the chassis by fusing an inertial measurement unit (IMU) array and suspension displacement sensors. The IMU array is used to remove acceleration interference from the accelerometer and obtain the attitude of the chassis, while the kinematic analysis of the suspension is used to obtain the 6-degree-of-freedom (DoF) pose of the chassis. These two measurements are fused to improve attitude accuracy. The pose change of the chassis is filtered and used to generate a compensated manipulator pose through pose transformation. Finally, the inverse kinematics of the manipulator is used to compensate each joint. An experiment was conducted on a mobile manipulator, and the end position error was found to be less than 0.5 mm after chassis disturbance, demonstrating promising results.