【作者】 周伟；

【导师】 朱雅光；

【作者基本信息】 长安大学 ， 机械工程， 2023， 硕士

【摘要】 六足机器人作为一种新型机器人,具有多自由度的肢体结构和离散的落足点,展现出极强的运动能力和适应性。然而,六足机器人在复杂崎岖地形下的运动控制仍然面临着巨大的挑战,因为这些环境下存在着不可预测的外界干扰,这些干扰可能会导致机器人失稳并且无法准确地运动。因此,本课题针对六足机器人在崎岖地形下的运动控制展开研究,其具体研究内容总结如下:首先,为了满足六足机器人的运动需求,以蚂蚁为仿生原型,基于低惯量原则设计了一款三自由度的机械腿及一种封闭式、紧凑型的轻质箱型机体结构,并使用Ansys Work Bench软件对腿部受力部件进行应力、应变分析,验证其结构的合理性及可靠性。其次,本文对六足机器人系统进行了运动学和动力学分析,旨在建立一个完备的数学模型来描述其运动特性。在运动学部分,通过创建腿部系统的D-H模型,并利用几何法和代数法联合求解,求出机器人的运动学解,还求解了足端雅可比矩阵和足端工作空间。动力学部分,先创建腿部动力学模型,再使用拉格朗日功能平衡法,可求出腿部各关节的驱动力矩值。然后,本文利用中枢模式发生器(CPG)的输出信号进行相位延迟以生成各腿的控制信号,再利用该控制信号完成六足机器人三足、四足和五足步态的运动控制,并利用该信号作为足端轨迹的驱动信号,完成对机器人摆动相足端基于贝塞尔曲线的轨迹规划。并通过Gazebo软件对六足机器人进行步态仿真,验证机器人在CPG信号控制下,完成三种步态运动的效果。最后,采用了一种基于虚拟模型控制的六足机器人运动控制策略,用以提高机器人在崎岖地形下的运动稳定性。该方法主要包含摆动相虚拟模型、支撑相虚拟模型以及实现腿部摆动相与支撑相平稳切换的状态机。并利用Gazebo软件对该方法进行仿真验证,虚拟样机成功的完成了上下坡实验和穿越崎岖地形实验,初步验证该控制策略的有效性。为更进一步验证该方法的有效性和可靠性,本文将该控制策略用于物理样机的爬坡实验和穿越崎岖地形实验。实验结果显示,该控制策略能够使机器人在复杂地形下有较好的运动稳定性。更多还原

【Abstract】 As a novel type of robot,the hexapod robot possesses a multi-degree-of-freedom limb structure and discrete foothold points,exhibiting remarkable mobility and adaptability.However,the motion control of hexapod robots in complex and rugged terrains remains a significant challenge due to the unpredictable external disturbances in these environments,which may cause the robot to become unstable and unable to move accurately.Therefore,this study focuses on the motion control of hexapod robots in rugged terrain,and the specific research content is summarized as follows:Firstly,In order to meet the motion requirements of hexapod robots and based on the bionic prototype of ants,a three-degree-of-freedom mechanical leg and a closed,compact,lightweight box-shaped body structure were designed based on the principle of low inertia.Ansys Work Bench software was used to perform stress and strain analysis on the leg force components to verify the rationality and reliability of the structure.Secondly,this article conducted a kinematic and dynamic analysis of the hexapod robot system,with the aim of establishing a complete mathematical model to describe its motion characteristics.In the kinematic part,the D-H model of the leg system was created,and the kinematic solution of the robot was obtained by using a combination of geometric and algebraic methods.The Jacobian matrix of the foot and the workspace of the foot were also solved.In the dynamic part,the dynamic model of the leg was first established,and then using the Lagrange’s equation,the driving torque values of each joint of the leg were obtained.Thirdly,this paper uses the output signal of the central pattern generator(CPG)for phase delay to generate the control signal of each leg,and then uses the control signal to complete the motion control of the three-legged,four-legged and five-legged gait of the hexapod robot.This signal is used as the driving signal of the foot end trajectory to complete the trajectory planning of the foot end of the robot’s swing phase based on the Bezier curve.And the gait simulation of the hexapod robot is carried out through the Gazebo software,and the effect of the robot completing three gait movements under the control of the CPG signal is verified.Finally,a hexapod robot motion control strategy based on virtual model control was adopted to improve the robot’s motion stability in rugged terrain.The method mainly includes a swing phase virtual model,a support phase virtual model,and a state machine that smoothly switches between the swing and support phases of the leg.The Gazebo software was used to simulate and verify the effectiveness of this method.The virtual prototype successfully completed uphill and rugged terrain experiments,preliminarily verifying the effectiveness of the control strategy.To further validate the effectiveness and reliability of the method,the control strategy was applied to physical prototypes for climbing and crossing rugged terrain experiments.Experimental results show that the control strategy can make the robot have better motion stability in complex terrain.更多还原