Abstract

Mobile manipulators commonly show disadvantages such as limited locomotion capabilities on uneven terrains and restricted manipulation capabilities for objects positioned outside the vertical direction of their workspace. To address these limitations, this paper proposes a control framework for mobile manipulator incorporating four lifts, one at each wheel. This configuration enhances the Degrees of Freedom (DoF) available for locomotion and manipulation tasks. To optimize the whole-body motion of the manipulator, we modified the Generalized Hierarchical Control (GHC) method to include the function of adjusting the weights of the joints. Experiments were conducted in both locomotion and manipulation scenarios with four different joint weight configurations. The locomotion experiment performed on a bumpy terrain, and the manipulation experiment, involving a circular motion task, demonstrated the benefits of utilizing the lifts. The results showed that weight adjustments led to a 55% reduction in unstable motion during locomotion and a 20% increase in manipulability during manipulation.

My contributions: 

• Enhanced a whole-body control framework to manage multiple tasks and joint weights at each priority level, improving arm workspace and enabling terrain-adaptive mobility

• Implemented a a Kalman filter for Mobile robot 6D pose estimation with IMU and encoder senesors.