Dynamics and stability of a hybrid serial-parallel mobile robot

Abstract

Kinematics, dynamics, and stability analysis of a hybrid serial-parallel wheeled mobile robot is detailed in this paper. Privileging the advantages of both serial and parallel robots, the suggested structure will provide higher stability for heavy object manipulation by a mobile robotic system. The proposed system is made of a differentially-driven wheeled platform, a planar parallel manipulator, which is called here as star-triangle (ST) mechanism, and a serial Puma-type manipulator arm. In order to develop a comprehensive kinematics model of the robot; first it is divided into three modules, i.e. a mobile platform, a parallel ST mechanism, and a serial robot. Next, a closed-form dynamics model is derived for the whole hybrid system based on a combined Newton-Euler and Lagrange formulation. Then, a careful validation procedure is presented to verify the obtained dynamics model. Finally, using the new postural stability metric named as moment-height stability (MHS), the important role of the parallel ST mechanism for stabilizing the mobile robotic system is demonstrated. The obtained results show that the proposed hybrid serial-parallel arrangement effectively enhances the tip-over stability of the overall mobile robotic system. Hence, it can be successfully exploited to prevent tip-over instability particularly during heavy object manipulation tasks.

Efficient kinematic solution to a multi-robot with serial and parallel mechanisms

“…Recently, there has been an increasing interest using parallel mechanism for designing mobile robots [15]. A reconfigurable parallel mobile robot which can be configured to 4R and 5R closed kinematical chains is proposed in [16].…”

Optimal Control of a Wheeled Mobile Cable-Driven Parallel Robot ICaSbot with Viscoelastic Cables

“…In ref. [4], Moosavian et al proposed the design of a hybrid serial-parallel WMR. They presented the kinematics, dynamics, and stability analysis of the mentioned system.…”