Bio-Inspired Piezo-Robots

Page
  • Legged Robot inspired by the Bounding gait locomotion of the African Dung Beetles

The locomotion technique shown in the video below is known for animals as the bounding gait locomotion which is a form of legged locomotion generally observed when a quadruped animal is running at the highest speed.

The bounding gait locomotion of a Legged Robot inspired by the African Dung Beetles is illustrated in the figure below.

Visual illustration of bidirectional locomotion (going forward/right) & (going backward/left) during one period T

From Figure, the Legged Robot lands with one leg and brings the other leg in the direction of motion to achieve one leg step on a half period T/2. Then in the next half period, the legs switch their roles for the next leg step.

  • Robot Architecture

The robot consists of one piezoelectric patch, a metal beam, two rigid legs, and the various electrical components as shown.

The piezoelectric robot with & without power electronics
  • Locomotion Principle

The locomotion is similar to bounding gait of dung beetle. Forward and Backward motion is realized by attaching legs at appropriate location along the unimorph actuator driven at two different modal frequencies.

Robot locomotion behavior at two different modal vibrations
  • Design Principle

The robot can be designed by identifying zones on the superimposed modal shapes of the unimorph actuator for legs placement.

• Euler Bernoulli Beam Theory


• Natural Frequency
• Modal Shape

Mode shapes and legs positions at f1 and f2 for the piezoelectric unimorph actuator
  • Kinematics of the Legged robot

The trajectory is derived for the case where the legs are positioned on the left side of the wave antinodes as shown

Under standing wave vibration, the tip of the leg moves in a diagonal motion. The kinematic motion of this leg can be formulated easily
  • Steady state response (z-displacement) for the unimorph actuator under a sinusoidal electrical field
  • Kinematics equations

where

And

where

  • Experimental verification
The obtained experimental speed versus applied voltage performance of the PMR operating on a flat surface. They show agreement to a certain degree
  • Unidirectional motion of the Legged Piezoelectric Miniature Robot (LPMR)
  • Bidirectional motion of the Legged Piezoelectric Miniature Robot (LPMR)
  • Steerable Miniature Legged Robot Driven by a Single Piezoelectric Unimorph Actuator
  • Design and Gait Analysis of a Two-Legged Miniature Robot with Piezoelectric-Driven Four-BAr Linkage
3D model of Two-Legged Miniature Robot with Piezoelectric-Driven Four-Bar Linkage
Gait cycle model of the piezoelectric robot
  • PISCES: A Highly Maneuverable and Untethered Under-Actuated Legged Piezoelectric Miniature Rob
A CAD model of PISCES
Overall Locomotion principle of the PISCES (a)
Placement of the Center of Mass (CM) and Identified positions
of the legs, (b) Friction forces generated at the leg at Mode order
1, (c) Friction forces generated at the leg at Mode order 2, (d)
Friction forces generated at the leg at Mode order 3
A prototype video for a tetherless PISCES
  • References
  1. Hassan H. Hariri, Gim Song Soh, Shaohui Foong, Kristin L. Wood, ‘’Pisces – A Highly Manoeuvrable And Untethered Under-Actuated Legged Piezoelectric Miniature Robot’’, Proceedings of the ASME 2019 International Design Engineering Technical Conferences and Computer and Information in Engineering Conference IDETC/CIE 2019, August 18-21, 2019, Anaheim, CA, USA
  2. A. G. Dharmawan, H. H. Hariri, G. S. Soh, S. H. Foong, and K. L. Wood, 2017, “Design, Analysis, and Characterization of a Two-Legged Miniature Robot with Piezoelectric-Driven Four-Bar Linkage”, ASME Journal of Mechanisms and Robotics, 2018.
  3. A. G. Dharmawan, H. H. Hariri, G. S. Soh, S. H. Foong, and K. L. Wood, 2017, “Design and gait analysis of a two-legged miniature robot with piezoelectric-driven four-bar linkage”, ASME International Design Engineering Technical Conferences, IDETC2017, August 6-9, 2017, USA
  4. Audelia Gumarus Dharmawan, Hassan Hussein Hariri, Gim Song Soh, Shaohui Foong, and Kristin Wood, ‘’Steerable Miniature Legged Robot Driven by a Single Piezoelectric Bending Unimorph Actuator’’, International Conference on Robotics and Automation (ICRA), May 29-June 3, 2017, Singapore
  5. H. H. Hariri, G. S. Soh, S. Foong, and K. Wood, ‘’Locomotion Study of a Standing Wave Driven Piezoelectric Miniature Robot for Bi-directional Motion’’, IEEE Transaction on Robotics, 2017.
  6. Hassan H. Hariri, Leonardus A. Prasetya, Shaohui Foong, Gim Song Soh, Kevin N. Otto and Kristin L. Wood ‘‘A Tether-less Legged Piezoelectric Miniature Robot Using Bounding Gait Locomotion for Bidirectional Motion’’, International Conference on Robotics and Automation (ICRA), May 16-21, 2016, Stockholm, Sweden
  7. H. Hariri, G. S. Soh, S. H. Foong, K. L. Wood, K. Otto, ‘’Miniature Piezoelectric Mobile Robot driven by Standing Wave’’, 14th World Congress in Mechanism and Machine Science, Taipei, Taiwan, 25-30 October, 2015