Fig. 6From: A vacuum-driven rubber-band gripperRelationship between the contraction force and difference between the inside air pressure when the actuator is fixed to the instrument and that at measurement (− 75 kPa). The contraction force was almost proportional to the differential air pressure. The steep increase over − 70 kPa could be attributed to the change in the cross-sectional area by dents on the surface of the actuatorBack to article page