丘陵山地仿脚踝弓腰式行走机构行驶机理及姿态控制策略研究

The mechanization of hilly area is the short-board restricting the realization of agricultural mechanization in China. The core reason lies in the lack of adaptability of the existing agricultural machinery equipment to the complex terrain of Hilly Area, especially the large slope. In order to solve this problem, this project innovatively puts forward the principle structure of bionic-ankle hunched-type driving device. that is, the slope-like walking mode which imitates the human foot movement characteristics. The biomechanical model of ankle structure is established by fusing biomechanics, biomimetic feature parameter extraction and finite element analysis and other methods to carry out topological research. The law of foot movement mode on plantar stress and pressure distribution under different terrain is proved, and the principle of ankle arch waist driving mechanism is put forward. Based on the biomechanical model of ankle structure, the flexible joints, driving modes and center-of-gravity position are considered comprehensively to explain the mechanism of machine-ground coupling in terrestrial profiling mode. The cooperative control strategy of the driving attitude of the mechanism is studied. Combined with the kinematics and dynamics analysis of steering and pitching movement, a composite optimization model of the hunched-type driving device based on the attitude control is established, and the mechanism of the influence of the driving posture of the slope on the ground adaptability is explored. The research theory and method opens up a new way to study the high throughput of power chassis. It will provide important technical and theoretical support for helping to break through the "last kilometer" of agricultural production mechanization in China.

丘陵山区农业机械化是目前我国实现农业全面机械化的制约短板，核心原因在于现有农机装备缺乏对丘陵山区复杂地形尤其是较大坡度的适应性。针对这一问题，本项目创新提出仿脚踝弓腰式行走机构思路，即仿人体足部运动特性的坡地仿形行走方式。拟融合生物力学、仿生特征参数提取、有限元分析等多种方法进行拓扑研究，建立脚踝结构生物力学模型，探明不同地形下足部运动方式对足底受力及压力分布的作用规律，提出仿脚踝弓腰式行走机构原理；以脚踝结构生物力学模型为基础，综合考虑柔顺关节、驱动方式、重心位置等影响因素，阐明地面仿形模式下机-地耦合作用机理，研究机构行走姿态协同控制策略，结合转向、俯仰运动学及动力学分析，建立基于姿态控制的弓腰式行走机构复合优化模型，探索坡地仿形行走位姿对地面适应性的影响机理。该研究理论和方法开辟丘陵山地动力底盘高通过性研究新思路，为助力打通我国农业生产全程机械化“最后一公里”提供重要的技术理论支撑。

丘陵山区农业机械化是目前我国实现农业全面机械化的制约短板，核心原因在于现有农机装备缺乏对丘陵山区复杂地形尤其是较大坡度的适应性。本项目针对丘陵山区农业装备非结构作业环境，提出了弓腰式行走机构并进行了分析研究，主要内容如下：.①针对丘陵山区农机作业非结构环境，分析研究了多种行走系统的优势与不足，采用轮履结合的可姿态调整行走机构作为研究方向。提出了适用于丘陵山区的仿脚踝弓腰式行走机构原理，确定了样机设计方案、结构以及各机构模块的主要参数。.②对弓腰式行走机构进行坡度稳定性分析，建立了弓腰式行走机构上坡和下坡的纵向稳定性模型，以及直线行驶的横向稳定性模型，得出不同情况下坡度稳定性的条件，通过分析得到了坡度和整机参数是影响弓腰式行走机构稳定性的决定性条件。.③对弓腰式行走机构越障性能进行了理论分析,分析了整机的质心公式以及越障时质心变化规律。研究了弓腰式行走机构在典型地形下斜坡、沟槽、凸台的越障过程，建立了越障运动学方程和动力学方程，为行走机构越障控制策略奠定了理论基础。.④对影响弓腰式行走机构稳定性的关键部件车架进行了强度分析和模态分析，验证其在作业过程中有足够的强度与刚度。并对弓腰式行走机构样机展开综合性能试验：行驶速度试验、偏驶率试验、最小转向半径试验、坡度稳定性试验、跨越垂直障碍物试验和沟槽越障试验。验证了前期研究的合理性。.本项目对弓腰式行走机构进行了研究，分析了其结构几何特征、运动学和动力学特征，并融合地形、土壤、机构等多方面因素，分析了不同地形情况下行走机构-地面耦合作用机理，研究结果表明：仿脚踝弓腰式行走机构的稳定性及越障性能都可适应丘陵山区非结构工作环境。在理论分析的基础上，进一步通过样机试验验证了仿脚踝弓腰式行走机构的高通过性，为丘陵山地动力底盘高通过性研究提供理论参考。