Soft Actuators with Stiffness and Shape Modulation


Executive Summary


Accurate and stable robotic systems have traditionally been constructed using rigid materials. However, soft and deformable structures have seen growing interest and application in recent years because they tend to outperform rigid systems. Soft robotics is a subfield that utilizes soft and deformable features, similar to ones found in nature and living organisms, to construct alternative robotic systems. Perhaps the most important characteristic of soft robots is their integration with stiffness tuning to allow components, such as robotic joints, to soften actively and move with increased flexibility. This stiffness variability enables adaptively modulating the load-bearing capability, shape, and locomotion behavior of the robots. Mechanisms with controllable stiffness can be applied to a wide range of tasks, including adaptive vibration damping, control of manipulators, mechanical modulation of cell growth, universal orthopedic casts, customized seating, manufacturing, and adaptive aerodynamic surfaces.


Description of Technology


Current methods for stiffness tuning of soft robotic components, specifically soft pneumatic actuators, are restricted by long-term viability, the requirement of vacuums and/or expensive hardware. These issues were taken into account by a team of innovators at MSU who have designed a deformable gripping surface demonstrated with a soft pneumatic actuator. A new approach to controlling stiffness and shape tuning is used in this design to allow the actuator to bend and move at virtual joints to deliver desired motions and shapes.


Key Benefits

  • Eliminates the requirement of bulky, additional equipment to control the stiffness of the soft actuator
  • Raw materials are inexpensive and commercially available
  • Experimentally measured bending angles of the joints were highly consistent with the model-predicted bending angles



  • Manipulation
    • Assembly
    • Soft material handling
    • Food handling
    • Produce packaging
  • Biomedical
    • Robotic surgery
    • Medical equipment
    • Micro medical robots


IP Status: 


Knowhow and design documentation


Licensing Rights Available


full licensing rights




Dr. Xiaobo Tan, Mohammed Al-Rubaiai, Thassyo Pinto


Tech ID




Patent Information:

For Information, Contact:

Raymond Devito
Technology Manager
Michigan State University