A Unified Approach to Motion Control of Mobile Manipulators

Abstract

This paper presents a simple on-line approach for motion control of mobile manipulators comprising a manipulator arm mounted on a mobile base. The proposed approach is equally applicable to nonholonomic mobile robots such as rover-mounted manipulators and holonomic mobile robots such as tracked robots and compound manipulators. For wheeled mobile robots, the nonholonomic base constraints are incorporated directly into the task formulation as kinematic constraints. The configuration control approach is ex tended to exploit the redundancy introduced by the base mobility to perform a set of user-specified additional tasks during the end- effector motion while satisfying the nonholonomic base constraints (if applicable). This approach treats the base nonholonomy and the kinematic redundancy in a unified manner to formulate new task constraints. The computational efficiency of the proposed control scheme makes it particularly suitable for real-time implementation. Two simulation studies are presented to demonstrate the applica tions of the motion control scheme to a rover-mounted arm (non holonomic system) and to a tracked robot (holonomic system).

Motion planning and posture control of multiple n-link doubly nonholonomic manipulators

“…Mobile manipulators have been considered to tackle complicated problems such as the one described in this paper because of their mobility, which can classified into four types: 4,[9][10][11][12][13] (1) Type (h, h), where both platform and manipulator contain holonomic constraints; (2) Type (h, nh),…”

“…It is mainly because of this reason that only a small number of researchers consider type (nh, nh) manipulators for complex tasks. 11,12,14,28 While the control strategies of mobile manipulators can either be centralized such as in 9,10 or decentralized such as in, [11][12][13] to the best of the authors' knowledge, there is no decentralized acceleration control laws that solve the motion planning and posture control problem of multiple type (nh, nh) manipulators.…”

Kinematic modeling and redundancy resolution for nonholonomic mobile manipulators

“…Some authors add the nonholonomic constraints in the description of the differential kinematics [5], [6]. A more efficient formulation, adopted also in this work, explicitly entails the differential motions that are feasible w.r.t.…”

“…The problem is usually tackled at a first-order kinematic level (i.e., with (pseudo-)velocities as command inputs) since planning the motion of NMMs is essentially a kinematic problem, but inclusion of dynamic aspects has also been considered [9]. When an NMM is redundant for a given task (this concept requires some caution, see Section II), redundancy can be exploited by extending schemes already available for standard manipulators, e.g., task space augmentation [5], [10], [11] or pseudoinversion of the Jacobian and use of its null-space motion [12].…”

Point-to-Point Collision-Free Trajectory Planning for Mobile Manipulators

“…Some of the existing researches address the problem by using only kinematics. In [4] Seraji has proposed an approach which treats nonholonomic constraints of the mobile platform and the kinematic redundancy of the manipulator arm in a unified manner to obtain the desired end-effector motion. Bayle et al in the works [5,6] have proposed an algorithm based on a pseudo-inverse scheme taking into account a geometric constraint on the end-effector motion.…”