This paper presents a motion planning method for mobile manipulators for which the base locomotion is less precise than the manipulator control. In such a case, it is advisable to move the base to discrete poses from which the manipulator can be deployed to cover a prescribed trajectory. The proposed method finds base poses that not only cover the trajectory but also meet constraints on a measure of manipulability. We propose a variant of the conventional manipulability measure that is suited to the trajectory control of the end effector of the mobile manipulator along an arbitrary curve in three space. Results with implementation on a mobile manipulator are discussed.

Presents the velocity kinematic modeling of wheeled mobile robots (WMRs) by applying the matrix coordinate transformation to every pair of WMRs including wheeled pairs which were dealt with in ad-hoc manners in previous methodologies. A wheeled pair is not replaced with a planar pair and its kinematics is formulated together with those of lower pairs, even though there exists 2 DOF motion at a wheeled pair. The proposed method is implemented successfully to obtain the forward velocity kinematics of a WMR, and it is therefore regarded as a real counterpart to transformation methodologies widely used for kinematics of the robot manipulators.

The 2-trowel type concrete floor finishing robot can move in any direction and rotate without any mechanism such as wheels by adjusting the posture of trowels. It utilizes the unbalanced friction forces occurring between the rotary trowels and the floor. Since the quality of the smoothed and polished concrete floor is determined by plastering speed, we need to control the velocity of the robot. However, we cannot use the typical velocity control method because it is very difficult to measure the velocity of the robot, in contrast to the mobile robots with wheels. To overcome this difficulty, the following are studied in the paper. We found that the robot dynamics has disturbance depending on its velocity, and showed that there exists the saturated velocity of the robot which is set by the posture of the trowels, and obtained the relationship between the saturated velocity and the posture in the translation and the rotation. These enable us to control the velocity of the robot only by adjusting the posture of trowels. We built the trowelling robot and are experimenting its performance with the proposed velocity control method.

A omni-directional self-propulsive trowelling robot is proposed. The proposed robot with two rotary trowels does not require any mechanism such as wheels to obtain driving forces. When the robot flattens a concrete floor with its two rotating trowels, the unbalanced friction forces occur between the trowels and the concrete floor. These friction forces are used to move the robot. Thus, the robot can move in any direction by controlling the two rotary trowels properly. In this paper, firstly the driving force for each trowel is computed by deriving the friction force between the trowel and the concrete floor. Secondly, the relationship between the driving force for the robot and the control variable of the robot is derived. Finally, the basic motions of the robot are realized by using the obtained relationship. This paper figures out how the concrete floor finishing robot with two trowels moves and will contribute to realizing it.