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Robust velocity control for an A-shaped micro-robot with stick-slip locomotion

Moradian, H ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1177/0954406215596358
  3. Publisher: SAGE Publications Ltd
  4. Abstract:
  5. In this paper, the problem of velocity control of a micro-robot's locomotion with nanometric resolution has been investigated. A sliding, A-shaped micro-robot, used in precision positioning applications is analyzed. This micro-robot is actuated by means of a piezoelectric stack actuator in order to produce translational and periodic motion. A dynamic model of the robot is proposed assuming linear behavior for the piezoelectric stack and Coulomb friction model. Then, in order to control the velocity of micro-robot, first a robust sliding mode control is used so that the relative angle between the legs in the micro-robot tracks a periodic reference signal. The velocity tracking for the micro-robot is achieved using an amplitude modulation strategy by adapting the amplitude of this reference signal. Velocity control of locomotion is assumed to be in the presence of a non-separation constraint (between the legs and the substrate) and friction uncertainties. Also, a state observer is designed to estimate the rate of change of the relative angle between the legs of the micro-robot, which is needed in the velocity control algorithm. Finally, simulation results are presented which illustrate the effectiveness of the proposed control strategy
  6. Keywords:
  7. Algorithms ; Friction ; Piezoelectricity ; Robots ; Robust control ; Signal processing ; Sliding mode control ; Slip forming ; Stick-slip ; Tribology ; Velocity ; Velocity control ; Coulomb friction models ; Friction-based locomotions ; Micro robotics ; Nanometric resolution ; Periodic reference signals ; Piezoelectric stack actuators ; Precision positioning ; Separation constraints
  8. Source: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 230, Issue 14 , 2016 , Pages 2413-2426 ; 09544062 (ISSN)
  9. URL: http://journals.sagepub.com/doi/10.1177/0954406215596358