In this paper, adaptive robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. The proposed control is robust not only to parameter uncertainties such as mass variations but also to external ones such as disturbances. The stability of the closed-loop system and the boundedness of tracking errors are proved using Lyapunov stability synthesis. The proposed control strategies guarantee that the system motion converges to the desired manifold with prescribed performance and the bounded constraint force. Simulation results validate that the motion of the system converges to the desired trajectory, and the constraint force converges to the desired force

http://robotics.nus.edu.sg/sge/journal/constrainedrobot/SMCB-mobilemanipulator-06-07.pdf

Adaptive Robust Motion/Force Control of Holonomic-Constrained Nonholonomic Mobile Manipulators

A general framework for the feedback control of mobile manipulators is proposed. Its main originality lies in its capacity to address in a unified manner both cases of omnidirectional and nonholonomic mobile platforms. It also allows for the execution of the desired manipulation task without the manipulator colliding into its joint limits, whenever these two objectives are compatible. This is obtained without having to rely upon trajectory planning. In the nonholonomic case this feature, which is not demonstrated for previous feedback control schemes proposed in the literature, is instrumental for performing reflex maneuvers automatically. It relies upon the concept, used in the control design, of a companion omnidirectional frame associated with the physical platform. The generality of the approach can be appreciated from its applicability to various nonholonomic platforms, for example unicycle-type and car-like.

/pdf/a-framework-for-the-control-of-nonholonomic-mobile-4euvj70dvy.pdf

A Framework for the Control of Nonholonomic Mobile Manipulators

The work presented in this paper aims at providing a unified modelling framework for the reactive control of wheeled mobile manipulators (WMM). Where most work in the literature often provides models, sometimes simplified, of a given type of WMM, an extensive description of obtaining explicit kinematic and dynamic models of those systems is given. This modelling framework is particularly well suited for reactive control approaches, which, in the case of mobile manipulation missions, are often necessary to handle the complexity of the tasks to be fulfilled, the dynamic aspect of the extended workspace and the uncertainties on the knowledge of the environment. A flexible reactive framework is thus also provided, allowing the sequencing of operational tasks (in our case, tasks described in the end-effector frame) whose natures are different but also an on-line switching mechanism between constraints that are to be satisfied using the system redundancy. This framework has been successfully implemented in simulation and on a real robot. Some of the obtained results are presented.

/pdf/kinematic-and-dynamic-model-based-control-of-wheeled-mobile-7l6ga2mp8i.pdf

Kinematic and dynamic model-based control of wheeled mobile manipulators: A unified framework for reactive approaches

This survey provides the basis for developing research in the area of mobile manipulator performance measurement, an area that has relatively few research articles when compared to other mobile manipulator research areas. The survey provides a literature review of mobile manipulator research with examples of experimental applications. The survey also provides an extensive list of planning and control references as this has been the major research focus for mobile manipulators which factors into performance measurement of the system. The survey then reviews performance metrics considered for mobile robots, robot arms, and mobile manipulators and the systems that measure their performance, including machine tool measurement systems through dynamic motion tracking systems. Lastly, the survey includes a section on research that has occurred for performance measurement of robots, mobile robots, and mobile manipulators beginning with calibration, standards, and mobile manipulator artifacts that are being considered for evaluation of mobile manipulator performance.

/pdf/survey-of-research-for-performance-measurement-of-mobile-99rqcgyv9j.pdf

Survey of Research for Performance Measurement of Mobile Manipulators.

Intelligent mobile manipulator navigation using adaptive neuro-fuzzy systems

This paper concerns the modeling and control of a mobile manipulator which consists of a robotic arm mounted upon a mobile platform. The equations of motion are derived using the Lagrange-d'Alembert formulation for the nonholonomic model of the mobile manipulator. The dynamic model which considers slip of the platform's tires is developed using the Newton-Euler method and incorporates Dugoff's tire friction model. Then, the tracking problem is investigated by using a well known nonlinear control method for the nonholonomic model. The adverse effect of the wheel slip on the tracking of commanded motion is discussed in the simulation. For the dynamic model, a variable structure control approach is employed to minimize the harmful effect of the wheel slip on the tracking performance. The simulation results demonstrate the effectiveness of the proposed control algorithm.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0263574798000873

J. H. Chung

Papers

Modeling and control of a mobile manipulator