基于脊-腿协调模型的脊柱型四足机器人高速奔跑机理研究

By reference to cheetah’s musculoskeletal system, the spinal joints are introduced to quadruped robot body while integrated with legs，which could increase the step length significantly and reduce standing time and back-swing time. It has been widely accepted a good way for quadruped robot to achieve high-speed locomotion. However, at present, research on spine driving and spine-leg coordination are limited：lack of a reasonable spinal-motion model ,spinal joints isolate from the original SLIP model, difficult to form spine-leg coordination ,etc. To solving the problems, in the subject we design a double-joint spine with animal characteristics to explore the high-speed locomotion mechanism. By reference to animals’ spine-leg movement, a spine-leg coordination model based on ‘alternating SLIP’ is built to avoid perturbation to original rigid body’s leg model, and solve the contradiction between large leg-span and friction angle. With reference to front/rear limb movement independence in rigid body’s bounding and galloping gait, in the sagittal plane, a spine-leg coordination model will be established to fulfill the coordinated locomotion of the double center between front legs and rear legs. Finally, system experiments will be taken to verify the mechanism of high-speed locomotion. The research on high-speed locomotion mechanism of backboned quadruped robot based on spine-leg coordination model will lay an theoretical basis for the realization of quadruped robot’s high speed locomotion, and make the robot has dynamic and stable feature with high level.

参照猎豹骨骼肌肉系统，在四足机器人刚性躯体上引入脊柱、协调脊-腿运动能够增大跨步步长，减少腿部着地及回摆时间，是实现四足机器人高速奔跑的有效手段。然而现阶段对脊柱的研究还存在很大局限：缺乏合理的脊柱驱动模型；忽视对原有模型的扰动，脊柱运动孤立，难以实现脊-腿协调，提速效能不显著。针对这些不足，本课题从仿生学出发构建符合动物运动特征的双关节脊柱构型，探究脊柱驱动原理与提速机制；参照动物脊-腿运动时序与力/位关系，建立单腿“交替弹簧倒立摆”脊-腿协调模型，解决脊柱对原有刚性躯体腿部模型的扰动，解决大跨步步长和地面摩擦角的矛盾，实现脊腿协调运动。参照刚性躯体跳跃步态、飞驰步态前后肢运动的独立性，建立矢状面内脊腿协调模型，实现脊柱参与下的前后肢双质心协调运动。揭示基于脊-腿协调模型的机器人高速运动机理为提升脊柱型四足机器人运动的高动态性、实现高速、稳定的奔跑提供了理论基础及解决方案。

四足机器人拥有典型的高冗余度多支链、拓扑结构实时动态变换等特点。为提高机器人的运动速度和灵活性，解决高速奔跑运动中存在极短的足-地接触时间、极大的着地冲击及强非线性运动耦合等问题，本项目参照猎豹骨骼肌肉系统，在四足机器人刚性躯体上引入脊柱环节，构建适用于高速奔跑运动的矢状面内双关节脊柱模型，并探究脊柱驱动原理。针对脊柱引入对原有肩/髋关节 SLIP 模型的扰动和大跨步步长需求，结合动物脊-腿运动时序提出单腿“交替弹簧倒立摆”模型，进而建立了矢状面内脊-腿协调模型，实现脊柱参与下的前后肢协调运动，最大程度地提高四足机器人的运动能力，实现机器人系统的有机协调。搭建脊柱型四足机器人平台展开实验研究，实现了机器人的高速奔跑运动。.项目按计划完成了各项研究内容，达到预期研究目标。首次提出了“交替弹簧倒立摆”脊-腿协调模型，并基于此模型构建了满足跨步步长和摩擦角约束的脊-腿协调运动控制策略，解决了脊柱引入对原有虚拟足的扰动及触地角超出摩擦锥导致足尖打滑等问题，实现了SLIP模型从单足到四足再到平面脊柱型四足机器人的统一及机体运动的有机协调。