“…8,9 Currently, the variable stiffness approach is divided into two categories. One approach is the formation of antagonism between structures that are affected by antagonism forces greatly, popular with granular jamming, 10,11 layer jamming, 12,13 and the antagonistic actuation scheme. 14 Another one is the change in elastic modulus of materials that include thermoplastic polymers (TPs), 15 low melting point alloys (LMPAs), 16 liquid metals, 17,18 electrorheological (ER) materials, 19 magnetorheological (MR) materials, 20 etc.…”