Overall Stiffness Optimization of 3-UCR Parallel Robot Leg Based on Conservative Congruence Transformation Theory

2012 ◽  
Vol 6 (1) ◽  
pp. 207-212
Author(s):  
Gang Cheng ◽  
Shirong Ge ◽  
Jingli Yu
Keyword(s):  
Parallel Robot ◽  
Transformation Theory ◽  
Stiffness Optimization ◽  
Robot Leg ◽  
Conservative Congruence Transformation ◽  
Congruence Transformation

Stiffness Analysis of 3-RPR Planar Parallel Mechanism to the Stiffness Control

2009 ◽  
Vol 16-19 ◽  
pp. 786-790 ◽  
Author(s):  
Shu Jun Li ◽  
Clément Gosselin
Keyword(s):  
Stiffness Matrix ◽  
Parallel Mechanism ◽  
Stiffness Analysis ◽  
Numerical Examples ◽  
Stiffness Control ◽  
Conservative Congruence Transformation ◽  
Stiffness Characteristics ◽  
External Forces ◽  
Congruence Transformation

The analytical stiffness equations of the 3-RPR planar parallel mechanism are derived in this paper based on the Conservative Congruence Transformation (CCT) stiffness matrix proposed in [1-3]. Stiffness maps of the 3-RPR mechanism are plotted in order to show the behaviour of the stiffness with and without external forces. The stiffness characteristics of the mechanism are analyzed and discussed in details. Numerical examples show that the stiffness in x and in y are well balanced, while the stiffness in tends to be lower.

scholarly journals Controllable Height Hopping of a Parallel Legged Robot

2021 ◽  
Vol 11 (4) ◽  
pp. 1421
Author(s):  
Zewen He ◽  
Fei Meng ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
Xuxiao Fan ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Parallel Robot ◽  
Legged Robots ◽  
Virtual Model ◽  
Torque Sensor ◽  
Dynamics Modeling ◽  
Active Compliance ◽  
Athletic Ability ◽  
Model Control ◽  
Robot Leg

Legged robots imitating animals have become versatile and applicable in more application scenarios recent years. Most of their functions rely on powerful athletic abilities, which require the robots to have remarkable actuator capacities and controllable dynamic performance. In most experimental demonstrations, continuous hopping at a desired height is a basic required motion for legged robots to verify their athletic ability. However, recent legged robots have limited ability in balance of high torque output and actuator transparency and appropriate structure size at the same time. Therefore, in our research, we developed a parallel robot leg using a brushless direct current motor combined with a harmonic driver, without extra force or torque sensor feedback, which uses virtual model control (VMC) to realize active compliance on the leg, and a whole-leg control system with dynamics modeling and parameter optimization for continuous vertical hopping at a desired height. In our experiments, the robot was able to maintain stability during vertical hopping while following a variable reference height in various ground situations.

Stiffness Analysis of 6-SPS Parallel Manipulator

2012 ◽  
Vol 468-471 ◽  
pp. 1220-1223
Author(s):  
Shu Jun Li ◽  
Qiao Ling Meng
Keyword(s):  
External Force ◽  
Stiffness Matrix ◽  
Parallel Manipulator ◽  
Joint Stiffness ◽  
Stiffness Analysis ◽  
Conservative Congruence Transformation ◽  
External Forces ◽  
And Behavior ◽  
Congruence Transformation

The analytical stiffness equations of 6-SPS spatial parallel manipulator were deduced based on the Conservative Congruence Transformation (CCT) stiffness matrix. The stiffness mappings of the 6-SPS manipulator were given to show the change and behavior of the stiffness with external forces acted on the manipulator. The results show that the stiffness of the 6-SPS manipulator is configuration dependent, and proportional to the actuating forces and joint stiffness. The stiffness is correlates not only to the magnitude of external forces but also the direction of the external force acted upon.

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