Looking to nature, animals frequently utilize tails to work alongside or in place of their legs to maneuver, stabilize, and/or propel to achieve highly agile motions. Although the single-link robotic tail shows its dynamical superiority and practical effectiveness in mobile platform maneuvering, most tails observed in nature have multi-link structures. Therefore, to investigate this novel tail structure, bio-inspired and biomimetic multi-link robotic tails were proposed and implemented. However, due to the lack of a whole-body dynamic model, previous research focused on investigating the tail subsystem independently without considering the mobile platform’s motions, which introduces deficiencies on both analysis and control. To bridge this theoretical gap, this paper presents a unified dynamics model that incorporates both the quadruped and the tail subsystems as a complete coupled dynamic system. Classical multibody dynamics formulation based on the principle of virtual work is utilized to derive the dynamic model. Based on the new whole-body dynamic model, three typical tail structures, including a single-link pendulum tail, a multi-link rigid tail, and a multi-link flexible tail are evaluated. The results indicate that by using a center of mass-based benchmark, the multi-link tail structure is dynamically equivalent to the single-link tail structure for bending motion. However, for rolling motions, the multi-link structure illustrates noticeable dynamical benefits compared to a single-link structure due to its higher inertia. In addition, a multi-link flexible structure shows significant oscillations and uncontrollable dynamic behaviors due to its under-actuation feature, which may limit its usage for highly dynamic applications.

放眼大自然，动物经常利用尾巴在腿部旁边或代替腿部工作，以操纵，稳定和/或推进以实现高度敏捷的动作。尽管单链接机器人尾巴在移动平台操纵中显示出其动态优势和实用有效性，但自然界中观察到的大多数尾巴都具有多链接结构。因此，为了研究这种新颖的尾巴结构，提出并实现了仿生仿生多链接机器人尾巴。但是，由于缺少全身动力学模型，以前的研究集中在不考虑移动平台运动的情况下独立研究尾部子系统，这引入了分析和控制方面的缺陷。为了弥合这一理论差距，本文提出了一个统一的动力学模型，该模型将四足动物子系统和尾部子系统合并为一个完整的耦合动力学系统。利用基于虚拟工作原理的经典多体动力学公式推导了动力学模型。基于新的全身动力学模型，评估了三种典型的尾巴结构，包括单连杆摆尾，多连杆刚性尾巴和多连杆柔性尾巴。结果表明，通过使用基于质心的基准，多连杆尾部结构在动态上等效于单连杆尾部结构进行弯曲运动。但是，对于滚动运动，由于其较高的惯性，因此与单连杆结构相比，多连杆结构具有明显的动力学优势。此外，