#  Variation: Morphology 

 



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   ![image20](/sites/g/files/omnuum4601/files/styles/hwp_1_1__360x360_scale/public/2024-11/image20.png?itok=1_htUH65) 

 

[Polygerinos et al. (2013)](/publications/towards-soft-pneumatic-glove-hand-rehabilitation)Even without changing the material, the actuator’s behavior can be modified by adjusting its shape (morphology). For example, simply making a wall thicker will make it stiffer than a thin wall of the same material.

As with material selection, predicting the behavior of a particular shape is difficult. FEM analysis and empirical testing can provide some insight, and the [Modeling](/book/pneunets-modeling) and [Testing](/book/pneunets-testing) sections contain information on how researchers have modeled and tested these PneuNets actuators.

For example, the FEM analysis and empirical tests carried out by [Polygerinos et al. (2013)](/publications/towards-soft-pneumatic-glove-hand-rehabilitation) yielded the following guidelines for morphology design:

   ![2.png](/sites/g/files/omnuum4601/files/styles/hwp_1_1__720x720_scale/public/sorotoolkit/files/2.png?itok=dTDOX176) 

 

- Thinner walls lead to an increased force output, and require less pressure for the actuator to reach maximum bending.

- Increased chamber height increases force output, but doesn’t seem to affect the trajectory of the actuator tip.

Empirical tests carried out by [Mosadegh et al. (2013)](/publications/pneumatic-networks-soft-robotics-actuate-rapidly) found that (for a fixed overall actuator length):

- Up to a certain plateau, increasing chamber height lowered the required pressure.
- Increasing the number of chambers also decreased the required pressure.
- Increasing chamber wall thickness increased the required pressure.



 

##  Bibliography 

Ilievski et al. (2011) [Soft robotics for chemists.](/publications/soft-robotics-chemists)

Mosadegh et al. (2013) [Pneumatic Networks for Soft Robotics that Actuate Rapidly.](/publications/pneumatic-networks-soft-robotics-actuate-rapidly)

Ogura et al. (2009) [Micro pneumatic curling actuator: Nematode actuator.](/publications/micro-pneumatic-curling-actuator-nematode-actuator)

Polygerinos et al. (2013) [Towards a soft pneumatic glove for hand rehabilitation.](/publications/towards-soft-pneumatic-glove-hand-rehabilitation)

Shepherd et al. (2011) [Multigait soft robot.](/publications/multigait-soft-robot-0)

Sun et al. (2013) [Characterization of silicone rubber based soft pneumatic actuators.](/publications/characterization-silicone-rubber-based-soft-pneumatic-actuators)



 

##  Contributors 

Panagiotis Polygerinos

Bobak Mosadegh

Alexandre Campo