【作者】 刘鑫宇；

【导师】 赵杰；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2011， 硕士

【摘要】 被动动力步行的设计思想要求其充分利用被动机器人自身的自然动力学特性,因此步行过程步态自然、能耗低。纯被动步行机器人仅依靠重力的作用就可以在斜坡上稳定行走,而准被动步行机器人能够依靠一定的控制在平地上稳定行走,步态同样自然。目前对准被动双足步行机器人的研究主要集中在控制方法对步行稳定性的影响及结构参数优化上,对步态的分析较少。为了更深入的研究准被动双足步行机器人的步态特征,本文研制了带躯体的准被动双足步行机器人样机,设计了能够调整刚度的串联弹性驱动单元,解决了膝关节的碰撞使稳定性降低的问题。深入研究并提出了准被动双足步行机器人的位置控制方法及电机目标输出角度的算法,解决了柔性驱动单元弹性元件伸长量计算不准确的问题。最终通过在ADAMS中对Pro/E中建立的样机仿真及实体样机试验来分析准被动双足步行机器人在平地上行走的步态特征,同时验证了结构参数及控制方法的正确性。首先,本文建立了被动双足步行机器人的动力学模型,对模型进行了结构参数优化。根据参数优化结果在ADAMS中建立了带躯体带膝关节的被动机器人仿真模型,根据仿真结果获得了被动机器人的在平地上行走的步态特征。其次,详细分析了柔性驱动单元的特点,指出了柔性驱动单元的刚度及平衡位置对准被动双足步行机器人步态特征的影响,并设计出了能够调整刚度的柔性驱动单元。在此基础上建立了带躯体及膝关节的准被动双足步行机器人的样机。然后,建立了摆动腿的转矩输入模型,并根据被动机器人动力学特性计算出了模型的控制参数。提出了准被动双足步行机器人的位置控制方法,结合驱动器特点提出了控制方法的具体实现方法,同时提出了计算电机目标输出角度的算法,解决了柔性驱动单元弹性元件伸长量计算不准确的问题。最后,通过Pro/E样机模型在ADAMS中仿真获得了准被动双足步行机器人在平地上行走的步态特征。最终通过实体样机实验,进一步分析了准被动双足步行机器人的步态特征,并验证了被动机器人结构参数、柔性驱动单元刚度及控制参数对步态特征的影响。更多还原

【Abstract】 The design of passive dynamic walking requires us to fully use of the natural dynamics of passive walkers, so the gait is natural and the energy consumption is low during walking. The pure-passive walking robots can walk on the slope stably only relying on gravity, while the quasi-passive walkers can walk on level ground naturally and stably under certain controls.Current research on passive biped robot mainly focuses on control strategies for walking stability and structure optimization, but less on gait character analysis. In order to get a better understanding of the quasi-passive biped robot walking gait characters, the paper developed a mechanical prototype of quasi-passive biped robot, and designed a series elastic actuator that can adjust the stiffness of the spring, and resolved the collision problem of the knee which can lead to instability of walking. On this basis, the paper made an intensive study of the control system of the quasi-passive biped robot and put forward the position control law of the DC motor. The motor target output angle algorithm was also put forward at the same time to solve the problem which can not calculate the extension of the spring correctly. At the end the paper used ADAMS to create a simulation of the prototype that was built in Pro/E and analyzed the gait characteristics of quasi-passive biped robot walking on level ground, and proved the correctness of the structural parameters and control strategies by walking experiment.First, the paper built a dynamic model of passive biped walking robot, and optimized the structural parameters of the model, and made a full analysis of how the different structural parameters can influence the stability of the passive walking robot. On the basis of optimization results, the paper built a simulation model with knee joint and upper body in ADAMS, and fully discussed the gait characters of this model.Secondly, the paper gave a detailed analysis of the characteristics of the flexible drive, and indicated that the stiffness and equilibrium position of the elastic actuator can influence the gait characteristics of passive walkers, and designed a new serials elastic actuator that can adjust the stiffness. Based on this, the paper then established the mechanical prototype of quasi-passive biped robot with upper body and knees.Then, the paper put forward the torque input model of the swing leg of quasi-passive biped robot and calculated out of the control parameters of this torque input model. Proposed a position control strategy of the quasi-passive biped walking robot, and proposed the implementation method according to the drive DC motor actuator’s property. In order to solve the problem which can not calculate the extension of the spring correctly, the paper put forward the target output angle algorithm.Finally, the paper used ADAMS to create a simulation of the prototype that was built in Pro/E and analyzed the gait characteristics of quasi-passive biped robot walking on level ground. Made a further analysis of the gait characteristics of quasi-passive biped robot by real experiment, and proved the influence of the structural parameters, the stiffness of elastic actuator and the control strategies on walking gait characteristics.更多还原