Humans rely on distributed tactile sensing in their hands to achieve robust and dexterous manipulation of delicate objects. Soft robotic hands have received increased attention in recent years due to their adaptability to unknown objects and safe interactions with the environment. However, the integration of distributed sensing in soft robotic hands is lacking. This is largely due to the complexity in the integration of soft sensing solutions with the hands. This paper proposes a novel soft robotic hand that incorporates an active palm and distributed pneumatic tactile sensing in both the fingers and the palm. Multi-material 3D printing allows the tactile sensors to be directly printed on the hand, whereas conventional tactile approaches require the sensors to be attached as part of multiple fabrication procedures. Active degrees of freedom are introduced in the palm to achieve increased dexterity. The proposed hand successfully performed 32 of the 33 Feix taxonomy grasps and all 11 Kapandji thumb opposition poses.

A multi-material 3D printed soft actuator is presented that uses symmetrical, parallel chambers to achieve bi-directional variable stiffness. Many recent soft robotic solutions involve multi-stage fabrication, provide variable stiffness in only one direction or lack a means of reliably controlling the actuator stiffness. The use of multi-material 3D printing means complex monolithic designs can be produced without the need for further fabrication steps. We demonstrate that this allows for a high degree of repeatability between actuators and the ability to introduce different control behaviours into a single body. By independently varying the pressure in two parallel chambers, two control modes are proposed: complementary and antagonistic. We show that the actuator is able to tune its force output. The differential control significantly increases force output with controllable stiffness enabled within a safe, low-pressure range (≤ 20 kPa). Experimental characterisations in angular range, repeatability between printed models, hysteresis, absolute maximum force, and beam stiffness are presented. The proposed design demonstrated a maximum bending angle of 102.6 • , maximum output force 2.17N, and maximum beam stiffness 0.96mN m 2 .

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