Robust Design Optimization of a 4-UPS-S Parallel Manipulator for Orientation-Regulating Control System of Solar Gather Panels

Table 3

Six-Sigma-based robust design and optimization results.

Variables	Initial scheme	Determinacy optimization scheme			Robust optimization scheme
		Determinacy optimal solutions		Six-Sigma analysis	Robust optimization analysis	Quality level
Input variables
	300		200.005	Sigma level 0.676; reliability 50.099%	213.330	6.356
			2.00005		2.13330
	200		129.096	Sigma level 7.142; reliability 100%	218.936	8.0
			1.29096		2.18936
	0.6		0.799	Sigma level 0.755; reliability 54.980%	0.683	8.0
			0.00799		0.00683
Output variables (performance indexes)
Global kinematic dexterity	0.310		0.305	Sigma level 1.187; reliability 76.47%	0.305	7.809
			0.007		0.007
Global minimum stiffness	30045		36880	Sigma level 4.161; reliability 99.99%	42991.7	7.563
			1721		1739
Global maximum payload capability	538.736		591.702		574.223
			4.276		4.014
Global maximum stiffness	290141		350500		329940
			5084		4624