Robots perform endless tasks in assembly lines and in factories making our work lighter and decreasing the need for human labour. The research in soft materials has opened new possibilities in robotics, creating a new field called soft robotics. By shifting from the hard robot materials to soft ones, the robots can be made safer; made to conform to objects; and made to feel comfortable against the skin.
For preserving the soft nature of the robot, all parts of the robot must be compliant. Traditional electric sensors are hard and thus cannot be used in soft robots.
The aim of this thesis is to research new gripper and sensor methods for soft robots. More specifically, the focus was to study new methods of fabricating soft robots and sensors for them, aiming at simpler ways to fabricate smarter soft robots with perception.
Two different 3D printed soft suction grippers were studied. The first gripper was pneumatic and the other one was hydraulic with magnetic stiffness switching.
"We noticed that higher holding forces were achieved by switching the gripper from soft to hard during the object transportation. Grippers with controllable stiffness switching can conform the object shapes during picking but also achieve high holding forces", Koivikko says.
Two different sensors were proposed in the doctoral thesis: electric screen-printed curvature sensors and pneumatic strain gauges.
"Screen-printing is a low-cost method suitable for mass manufacturing electric strain sensors, whereas soft pneumatic strain sensors are a step towards fully pneumatic soft robots."
"The benefit of fully pneumatic soft robots is that they do not need electric components. Thus, they can be used in strong radiation which can destroy electric components."
Koivikko is from Mikkeli and currently working in Bioinspired Materials and Robotics Group (PI Assoc. Prof. Veikko Sariola) in Tampere University. After her doctoral defence, she will continue her research on soft robots in Cornell University.
The doctoral dissertation of M.Sc. (Tech.) Anastasia Koivikko in the field of biomedical engineering titled Grippers and Sensors for Soft Robots will be publicly examined in the Faculty of Medicine and Health Technology at Tampere University at 12 o’clock on Friday 21 January 2022. The Opponent will be Reader Adam Stokes from the University of Edinburgh while Associate Professor Veikko Sariola will act as the custos.
The event can be followed via remote connection.
The dissertation is available online at
Photo: Vilma Lampinen