Design and implementation of a binary redundant manipulator with cascaded modules

Emmanouil Tzorakoleftherakis, Anastasia Mavrommati, Anthony Tzes

Research output: Contribution to journalArticlepeer-review


The subject of this paper is the design and implementation of a prototype snakelike redundant manipulator. The manipulator consists of cascaded modules eventually forming a macroscopically serial robot and is powered by shape memory alloy (SMA) wires. The SMAs (NiTi) act as binary actuators with two stable states and as a result, the repeatability of the manipulator's movement is ensured, alleviating the need for complex feedback sensing. Each module is composed of a customized spring and three SMA wires which form a tripod with three degrees of freedom (DOFs). Embedded microcontrollers networked with the I2C protocol activate the actuators of each module individually. In addition, we discuss certain design aspects and propose a solution that deals with the limited absolute stroke achieved by SMA wires. The forward and inverse kinematics of the binary manipulator are also presented and the tradeoffbetween maneuverability and computational complexity is specifically addressed. Finally, the functionality and maneuverability of this design are verified in simulation and experimentally.

Original languageEnglish (US)
Article number011002
JournalJournal of Mechanisms and Robotics
Issue number1
StatePublished - 2016


  • Binary actuators
  • Kinematics
  • Macroscopically serial
  • Redundancy
  • Robotic manipulator
  • Shape memory alloys

ASJC Scopus subject areas

  • Mechanical Engineering


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