基于气动肌腱驱动的拮抗式仿生关节设计与控制

关节是仿生机器人机械系统的基本组成元素。在面向环境交互的仿生机器人系统中,关节的质量、体积以及功/重比直接影响系统的工作性能。与传统的电气、液压驱动方式相比,采用气动肌腱的驱动方式具有质量小、体积小和高功/重比等优势,具有广阔的应用前景。从功能仿生角度出发,在分析人体肘关节骨骼结构特点和肌肉发力方式的基础上,设计一种基于气动肌腱驱动的拮抗式仿生关节。建立单根肌腱的数学模型,通过搭建气动肌腱工作特性试验平台对肌腱进行性能测试,采用最小二乘法对模型参数进行辨识。针对拮抗式仿生关节的构型进行运动学和动力学分析,提出基于肌腱模型的偏置输入气压控制方法,设计基于关节估计阻尼的扰动观测器对名义模型进行补偿,通过数值仿真对控制方法进行有效性验证。建立仿生关节运动控制试验系统,通过单关节轨迹跟踪试验验证了肌腱理论模型的正确性及控制策略的有效性。

Design and Control on Antagonistic Bionic Joint Driven by Pneumatic Muscles Actuators

The joint is a fundamental element of mechanical system of bionic robot.Within the bionic robot system toward environment interaction,the mass,volume and ratio of power/weight have impact on the performance of system.Compared to electrical and hydraulic drive,the method driven by pneumatic muscles has broad application prospect due to its lighter weight,smaller volume and larger ratio of power/weight.From the prospective function bionics,an antagonistic bionic joint driven by pneumatic muscles is designed based on the analysis of natural skeleton structure and strength generation of elbow joint.The model of pneumatic muscle is established.The performance test of pneumatic muscle is carried out on the experiment platform.The parameters of the model is identified though least square method.Directed by kinematics and dynamics analysis,a model-based control strategy of input pressure offset is proposed.The disturbance observer based on damping estimation is introduced for torque compensation of nominal model.The proposed strategy is verified by simulation.Furthermore,the test system of joint motion control is constructed.The validity of the theoretical model of pneumatic muscles and controller is testified by tracking experiments.