连续变刚度仿生驱动关节的设计与建模分析

doi:10.12382/bgxb.2023.0730

摘要/Abstract

摘要：

机器人仿生关节刚度连续变化功能的设计与控制是柔性驱动技术的难点问题。提出一种可连续变刚度的仿生驱动关节,该关节采用变力臂方式实现从低刚度到高刚度的连续变化,仿生驱动关节主副电机功率比大、结构紧凑。为了分析该仿生驱动关节的弹性变形与负载之间的刚度变化关系,建立有负载条件下的静力学方程,通过数值计算模拟得到关节刚度与主副电机的角度关系,并对仿生驱动关节进行力矩跟踪、阶跃响应和刚度跟踪3种实验。实验结果表明,新设计的变刚度驱动关节在16N·m的正弦输出力矩下,最大误差为1.23N·m,方差为0.19N·m,最大误差占总幅值的7.7%;在刚度跟踪为0.4~1.6N·m/(°)范围内、输出扭转角为5°时,误差最大为0.09N·m/(°),占总均值刚度的9.0%。

关键词: 变刚度驱动器, 双电机驱动, 仿生驱动关节, 刚度控制

Abstract:

The design and control of continuous variation capability of robot bionic joint stiffness are the difficult problems in flexible drive technology. In this paper, a bionic joint with continuously variable stiffness is proposed, in which the continuous change from low stiffness to high stiffness is achieved by using a variable moment arm. The main and secondary motors of the bionic joint have large power ratio and compact structure. In order to analyze the relationship between the elastic deformation of bionic joint and the stiffness variation of load, a static model with load conditions is established, and the relationship between the joint stiffness and the angle of main and secondary motors is obtained through simulation. The experiments of torque tracking, step response and stiffness tracking are conducted on the bionic joint. The experimental results show that the bionic joint with continuously variable stiffness has a maximum error of 1.23N·m with a variance of 0.19N·m at a sinusoidal output torque of 16N·m, with the maximum error being 7.7% of the total amplitude, and when the stiffness tracking is in the range of 0.4N·m/(°) to 1.6N·m/(°) for and the output torsion angle is 5°, the maximum error is 0.09N·m/(°), accounting for 9.0% of the total mean stiffness.

Key words: variable stiffness actuator, dual motor drive, bionic joint, stiffness control

中图分类号:

TP242

廖峻北, 伊烁闻, 雷飞, 刘思宇, 郭朝, 王志瑞, 闫曈, 党睿娜. 连续变刚度仿生驱动关节的设计与建模分析[J]. 兵工学报, 2023, 44(11): 3269-3278.

LIAO Junbei, YI Shuowen, LEI Fei, LIU Siyu, GUO Zhao, WANG Zhirui, YAN Tong, DANG Ruina. Design and Modeling of a Bionic Joint with Continuously Variable Stiffness[J]. Acta Armamentarii, 2023, 44(11): 3269-3278.

图/表 14

图1 变刚度原理图

Fig.1 Schematic diagram of variable stiffness

图2 结构设计图

Fig.2 Structural design

图3 弹簧杠杆原理图

Fig.3 Principle of spring lever

图4 刚度与角度关系图

Fig.4 Stiffness versus deflection and spiral angles

图5 力矩与扭转角关系图

Fig.5 Relationship between torque and deflection

图6 螺旋线齿轮力矩分析图

Fig.6 Torque analytical graph of Archimedean spiral gear

图7 动力矩与阻力矩分析图

Fig.7 Relation of active torque and resistance torque

表1 仿生关节参数

Table 1 Parameters of bionic joint

参数	取值
螺旋线齿轮齿数	78
副电机齿轮齿数	19
齿轮材料	45号钢
其他零件材料	6061合金
齿轮模数m/mm	1
杠杆总长a/mm	23
杠杆支点半径b/mm	33
副电机额定输出扭矩/(N·m)	3
主电机峰值输出扭矩/(N·m)	23
副电机峰值输出扭矩/(N·m)	3
驱动关节直径/mm	110
驱动关节轴向长度/mm	31
关节旋转角度/(°)	-120~120
弹性扭转角度/(°)	-10~10
弹簧劲度系数/(N·m)	7440.5
副电机额定转速/(r·min^-1)	469
主电机额定转速/(r·min^-1)	80

图8 样机与实验原理图

Fig.8 Prototype and experiment principle of VSA

图9 正弦力矩实验跟踪图

Fig.9 Sinusoidal torque experimental tracking results

图10 不同刚度下理论力矩与实际力矩比较图

Fig.10 Comparison between the theoretical and actual torque

图11 阶跃力矩实验跟踪图

Fig.11 Step torque experimental tracking results

图12 刚度跟踪实验图

Fig.12 Stiffness tracking experiment

表2 5种典型变刚度驱动器的性能对比

Table 2 Performance comparison of each VSA

名称	输出端直径/mm	最大输出力矩/(N·m)	输出刚度特性	质量/kg	刚度范围/(N·m·rad^-1)
仿生驱动关节	110	23	线性	1.6	17.20~286.62
AwAS^[24]	130	80		1.8	30~1300
b-b VSA^[31]		3	非线性		0.7~1.86
HVSA		17	非线性	2.36	4.01~126.05
SVSA^[28]	140	22.1	非线性	2.4	1.7~150.56
ESPaa^[30]	66	6.1	非线性	0.45	0.35~35

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