TABLE II.

Summary of Experiment #1

Subjects	16 (14 males, 2 females)
Task	moving a soft gripper along a predetermined trajectory, being as fast and precise as possible
Conditions	Visual feedback (Vs)
	Visual + Vibrotactile feedback (Vs + Vb)
	Visual + Frictional feedback (Vs + Pc)
	Kinesthetic feedback (K)
	Visual + Position-error feedback (Vs + Pe)
	Visual + Vibrotactile + Position-error feedback (Vs+Vb+Pe)
	Visual + Frictional + Position-error feedback (Vs + Pc + Pe)
	Kinesthetic + Position-error feedback (K + Pe)
Video	available as supplemental material
Best conditions (average)
	Completion time		K (42.38 s)
	Error in following trajectory		K + Pe (0.53 mm)
	Distance between reference and gripper		K + Pe (0.97 mm)
	Perceived effectiveness		K (8.26)
Statistical analysis (two-way repeated measures ANOVA)
Completion time (significant p values only)
	Factor 1: presence of Pe feedback (p = 0.001)
	Factor 2: feedback type (p < 0.001)
		Vs + Vb vs. Vs	p = 0.013
		Vs + Vb vs. Vs + Pc	p = 0.003
		Vs + Vb vs. K	p = 0.002
Error in following trajectory (significant p values only)
	Factor 1: presence of Pe feedback (p < 0.001)
	Factor 2: feedback type (p < 0.001)
		Vs vs. Vs + Vb	p < 0.001
		Vs vs. Vs + Pc	p < 0.001
		Vs vs. K	p < 0.001
		Vs + Vb vs. Vs + Pc	p < 0.001
		Vs + Vb vs. K	p < 0.001
		Vs + Pc vs. K	p < 0.001
Distance between reference and gripper (significant p values only)
	Factor 1: presence of Pe feedback (p < 0.001)
Perceived effectiveness
	Factor 1: presence of Pe feedback (p = 0.002)
	Factor 2: feedback type (p < 0.001)
		Vs vs. Vs + Vb	p < 0.001
		Vs vs. K	p < 0.001
		Vs + Vb vs. Vs + Pc	p < 0.001
		Vs + Vb vs. K	p < 0.001
		Vs + Pc vs. K	p < 0.001