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Updated: May 28, 2026

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Bioinspired Soft Robot with Incorporated Microelectrodes
Published on: February 28, 2020
A bioinspired hybrid robotic joint for safer physical human-robot interaction
Gianluca Dimonte1,2, Marta Gandolla2, Tommaso Proietti1,3
1The Biorobotics Institute and Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, Pisa, Italy.
Bioinspiration & Biomimetics
|May 26, 2026
Summary
This study introduces a hybrid robotic joint using rigid frames and soft pneumatic actuators for safer human-robot interaction. The novel design offers precise control and adaptable compliance, advancing soft robotics applications.
Area of Science:
- Robotics
- Materials Science
- Control Systems
Background:
- Growing demand for soft, compliant robotic systems in humanoids and wearables for safety and unstructured environments.
- Limitations of traditional rigid robotic mechanisms in human-robot interaction and adaptability.
Purpose of the Study:
- To present a hybrid control approach for a single-degree-of-freedom robotic joint combining rigid structure with soft pneumatic actuators.
- To develop and validate bioinspired pneumatic artificial muscles for precise and versatile robotic joint control.
Main Methods:
- Designed novel pneumatic artificial muscles using thermoplastic polyurethane (TPU) for high force and stretchability.
- Developed two model-free controllers for independent regulation of joint position and stiffness.
- Implemented a bioinspired antagonistic actuator configuration mimicking the human elbow.
Main Results:
- Achieved high isometric force (400 N at 240 kPa) and significant stretchability (80 mm) with low-density TPU actuators.
- Demonstrated precise angle control (< 2°RMSE) with minimal overshoot (< 1%) and fast response (< 1.3 s rise time).
- Successfully modulated joint stiffness (0.054-0.076 Nm/deg) and demonstrated concurrent control for dynamic behavior adaptation.
Conclusions:
- The hybrid robotic joint effectively combines rigid and soft actuation for adaptable and safe robotic systems.
- The developed TPU-based pneumatic artificial muscles offer competitive performance for advanced robotic applications.
- This work provides a foundational step towards multi-DOF coordination and wearable robotic integration.
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