Lab of Locomotion Bioinspiration and Intelligent Robots, College of Mechanical and Electrical Engineering, and College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
Soft Robot. 2023 Aug;10(4):713-723. doi: 10.1089/soro.2022.0080. Epub 2023 Feb 13.
The majority of sprawling-posture quadrupedal vertebrates, such as geckos and lizards, adopt a cyclical lateral swing pattern of their trunk that is coordinated with limb movements to provide extraordinary flexibility and mobility. Inspired by the gecko's locomotory gait and posture, a gecko-like robot with a flexible spine driven by shape memory alloy (SMA) springs was proposed in this work. The static parameters of the SMA spring were experimentally measured, and the flexible spine driven by SMA springs can be deflected bidirectionally. A kinematic model of the spine mechanism was established, and the mathematical relationship between the thermodynamic behavior of the SMA springs and spinal deflection was systematically analyzed. When a gecko trots with a lateral swing pattern of its trunk, the body and the spine show a standing wave shape and a single-peak C-type curve, respectively. The lateral spine deflection and trotting gait were combined in a collaborative model of a flexible spine and limbs to describe in detail the specific relationships between leg joint variables and spine deflection angle. Planar motion tests of a prototype robot were also conducted by using four high-speed cameras to record the trajectory of each point of the body, which verified the proposed model. From the acquired results, it was demonstrated that, compared with a rigid body, a robot with a flexible spine has a longer stride length, higher speed, and a greatly reduced turning radius.
大多数四足动物采用伸展姿势，如壁虎和蜥蜴，它们的躯干会周期性地侧向摆动，与四肢运动协调，从而提供非凡的灵活性和机动性。受壁虎运动步态和姿势的启发，本工作提出了一种具有由形状记忆合金（SMA）弹簧驱动的柔性脊柱的类壁虎机器人。实验测量了 SMA 弹簧的静态参数，并且 SMA 弹簧驱动的柔性脊柱可以双向偏转。建立了脊柱机构的运动学模型，并系统分析了 SMA 弹簧的热力学行为与脊柱偏转之间的数学关系。当壁虎以躯干的侧向摆动步态奔跑时，身体和脊柱分别呈现出驻波形状和单峰 C 型曲线。将侧向脊柱偏转和奔跑步态结合到柔性脊柱和四肢的协作模型中，详细描述了腿关节变量和脊柱偏转角度之间的具体关系。通过使用四个高速摄像机对原型机器人进行了平面运动测试，以记录身体每个点的轨迹，验证了所提出的模型。从获得的结果表明，与刚体相比，具有柔性脊柱的机器人具有更长的步长、更高的速度和大大减小的转弯半径。
