为实现微小型机器人的精密运动定位,提出一种基于粘滑运动原理的足式微小型机器人.机器人足由双压电膜驱动,本身为空间不等截面的弹性梁结构.首先建立了柔性足的有限自由度模型和机器人系统的动力学模型.然后根据粘滑驱动中的粘滞和滑移过程的不同特点,分别对粘滞过程的静力学与滑移过程的瞬态动力学进行了分析,得到了机器人运动位移、分辨力与驱动电压之间的关系,并分析了粘滞一滑移过程中摩擦力的变化以及足尖的状态切换过程.分析结果表明,在粘滞阶段,基体的静态位移与驱动电压近似呈线性关系,且随驱动电压的增高而增大;在滑移阶段,由于柔性足的振动及振动与摩擦力的耦合关系,足端的滑移距离及基体位移与驱动电压之间存在非线性关系.建立了机器人样机,对机器人的运动分辨力和位移响应进行了测试,实验数据显示,基于粘滑运动原理,机器人可以实现0.88um的高运动分辨力.
To achieve precision motion positioning, a legged micro robot is presented based on stick-slip motion principle. The legs composed of elastic beams with spatially unequal sections are driven by the piezoelectric bimorph. A finite DOF (degree of freedom) model of the flexible leg and a dynamic model of the robot system are built. Then, according to the different characteristics of sticky state and slippage state, statics analysis of the sticky state and transient dynamics analysis of the slippage state are conducted respectively. The relations of displacement versus voltage and of resolution versus voltage are obtained. The variation of friction force and state switch process of leg end during stick-slip process are analyzed. According to analysis results, it is found that the static displacement of the base is nearly linear with driving voltage at sticky state and will step up with the increase of driving voltage. And due to the vibration of the flexible leg and the coupling between the vibration and the friction, the slip displacement of the leg end and the displacement of the base are nonlinear with the driving voltage at slippage state. Finally, a robot prototype is developed, and the resolution and displacement response are tested. The results show that the presented micro robot can achieve the motion resolution of 0.88 μm based on stick-slip motion principle.