Multi-material, flexible robotic assembly with interlocking and elastic cables, embedded sensors, and actuators
A robotic assembly includes a plurality of rigid links formed from a first material and an elastic joint interconnecting a pair of rigid links of the plurality of rigid links. The elastic joint is formed from a second material. The robotic assembly also includes a conductive sensor coupled to the elastic joint and extending along at least one rigid link of the plurality of rigid links. The conductive sensor is formed from a third material. The plurality of rigid links, the elastic joint, and the conductive sensor are formed during a single printing process by a multi-material printer.
1 . A robotic assembly comprising:
a plurality of rigid links formed from a first material;
an elastic joint interconnecting a pair of rigid links of the plurality of rigid links, the elastic joint formed from a second material;
a conductive sensor coupled to the elastic joint and extending along at least one rigid link of the plurality of rigid links, the conductive sensor formed from a third material, wherein the plurality of rigid links, the elastic joint, and the conductive sensor are formed during a single printing process by a multi-material printer; and
an elastic cable coupled to a distal rigid link of the plurality of rigid links, the elastic cable formed from the second material.
2 . The robotic assembly according to claim 1 , wherein the distal rigid link includes an internal socket therein and a distal end of the elastic cable is embedded in the internal socket during printing of the distal rigid link and the elastic cable.
3 . The robotic assembly according to claim 1 , wherein the first material is a rigid polymeric material at room temperature and includes at least one of acrylonitrile butadiene styrene, polylactide, thermoplastic polyurethane, polyethylene terephthalate glycol, or polyetherimide.
4 . The robotic assembly according to claim 1 , wherein the second material is an elastic polymeric material at room temperature and includes thermoplastic polyurethane.
5 . The robotic assembly according to claim 1 , wherein the third material is an electrically conductive polymer and includes polylactide.
6 . The robotic assembly according to claim 1 , wherein the elastic joint has a closed loop structure.
7 . The robotic assembly according to claim 6 , wherein at least a portion of the closed loop structure is embedded in each rigid link of the pair of rigid links during printing of the elastic joint and the pair of rigid links.
8 . The robotic assembly according to claim 1 , wherein the conductive sensor includes a pair of conductive traces coupled to the elastic joint and extending in a longitudinal direction along the elastic cable.
9 . The robotic assembly according to claim 8 , wherein the conductive sensor is configured to sense a change in resistance in response to flexing of the pair of conductive traces.
10 . The robotic assembly according to claim 1 , further comprising:
a pulley coupled to a rigid link that is proximal of the distal rigid link, the pulley formed from the second material.
11 . The robotic assembly according to claim 10 , wherein the elastic cable is routed through the pulley.
12 . The robotic assembly according to claim 11 , wherein the elastic cable is configured to be coupled to an actuator configured to move the elastic cable thereby moving the distal rigid link.
13 . The robotic assembly according to claim 10 , wherein the pulley has a closed loop structure.
14 . The robotic assembly according to claim 13 , wherein at least a portion of the closed loop structure is embedded in the rigid link that is proximal of the distal rigid link during printing of the pulley and the rigid link that is proximal of the distal rigid link.
15 . A method for fabricating a robotic assembly, the method comprising:
receiving a design file at a multi-material printer, the design file including instructions for printing a robotic assembly including:
a plurality of rigid links formed from a first material;
an elastic joint interconnecting a pair of rigid links of the plurality of rigid links, the elastic joint formed from a second material;
a conductive sensor coupled to the elastic joint and extending along at least one rigid link of the plurality of rigid links, the conductive sensor formed from a third material; and
an elastic cable coupled to a distal rigid link of the plurality of rigid links, the elastic cable formed from the second material and having an internal socket defined therein;
printing the plurality of rigid links, the elastic joint, and the conductive sensor during a single printing process,
wherein a distal end of the elastic cable is embedded in the internal socket during printing of the distal rigid link and the elastic cable.
16 . The method according to claim 15 , wherein the design file includes instructions for printing:
a pulley coupled to a rigid link that is proximal of the distal rigid link, the pulley formed from the second material.
17 . The method according to claim 16 , further comprising:
printing the elastic cable and the pulley during the single printing process.
18 . The method according to claim 16 , wherein the first material is a rigid polymeric material at room temperature and includes at least one of acrylonitrile butadiene styrene, polylactide, thermoplastic polyurethane, polyethylene terephthalate glycol, or polyetherimide;
the second material is an elastic polymeric material at room temperature and includes thermoplastic polyurethane; and
the third material is an electrically conductive polymer and includes polylactide.
19 . A robotic assembly comprising:
a plurality of rigid links formed from a first material;
an elastic joint having a closed loop structure interconnecting a pair of rigid links of the plurality of rigid links, the elastic joint formed from a second material; and
a conductive sensor coupled to the elastic joint and extending along at least one rigid link of the plurality of rigid links, the conductive sensor formed from a third material, wherein the plurality of rigid links, the elastic joint, and the conductive sensor are formed during a single printing process by a multi-material printer.
20 . The robotic assembly according to claim 19 , wherein at least a portion of the closed loop structure is embedded in each rigid link of the pair of rigid links during printing of the elastic joint and the pair of rigid links.