Design and Modeling of a Bionic Joint with Continuously Variable Stiffness

doi:10.12382/bgxb.2023.0730

Abstract

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

CLC Number:

TP242

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.

Figures/Tables 14

References 31

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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

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

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

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