轮手一体机器人群体构形的模块化动力学建模方法

Modular Dynamics Modeling Approach of Group Configuration of Wheel-manipulator Robots

轮手一体机器人是一种模块化机器人,其单模块自由度多,结构相对复杂,群体构形形式多样,且需要经常重构以适应不同环境。采用传统方法对其进行动力学建模导致重复建模,机器人重构时更新量较多。针对此问题,提出一种基于模块化思想的群体构形动力学建模方法,减少了重复建模,且所得方程适用于串链、闭链、树形等各种拓扑构形。采用李代数作为局部坐标消除奇异位形,得到单模块机器人动力学方程的统一描述。根据群体构形的连接关系和连接类型定义接触集合和关节模型,建立约束力方程描述模块间的相互作用。针对动力学方程状态变量非矢量情况下的数值积分方法进行讨论,并给出实例仿真。

A wheel-manipulator robot, as a modular robot system, is characterized by multiple degrees of freedom and relatively complex architecture of the module. Modules of the wheel-manipulator robot can be combined to form various forms of group configuration. Moreover, the group configuration will often be reconfigured to fit into different environment. Conventional methods used to model the dynamics of modular robots will lead to duplicate work, and bring the large amount of data to be updated for reconfiguration. To solve this problem, a modular modeling approach is presented to obtain the general dynamics of group configuration of wheel-manipulator robots, which can eliminate duplicate modeling work. The resulting equations are suited for topologies of serial, closed-form, and tree-form. By using lie algebra as local coordinate, the dynamics of single module is derived, which is free of singularity. Contact sets and joint models are defined based on the relationship and types of connections between modules. Equations of constraint forces are formulated to describe the interactions between modules. Because the state variables of the dynamics equations are not vectors, the geometric numerical integration method is easily implemented. An example is provided to illustrate the validity of the dynamics equations and simulation process.