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The robotic spine has a lot of potential for snake-like, quadruped, and humanoid robots, as it can improve their mobility, flexibility, and overall function. A common approach to developing an articulated spine uses geared motors to imitate vertebrae. Instead of using geared motors that rotate 360 degree, a bioinspired gearless electromechanical actuator was proposed and developed as an alternative, specifically for humanoid spine applications. The actuator trades off angular flexibility for torque, while the geared motor trades off speed for torque. This article compares the proposed actuator and conventional geared motors regarding torque, acceleration, and copper loss for a vertebra's angular flexibility. When its angular flexibility is lower than 14∘, the proposed actuator achieves higher torque capability without gears than with conventional motors. Lower angular flexibility, which means smaller airgaps, allows the proposed actuator to produce a much stronger torque for the same input power. The actuator's nonlinear electrical and mechanical dynamics models are developed and used for position control of a six-module distributed spine. In addition, two different position-control architectures are developed: an outer loop proportional-integral (PI) position controller with an inner loop PI current controller and an outer loop PI position controller with an inner loop PI torque controller.
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System-Level Design Methodology for a Distributed Electromechanical Actuator in Bio-Inspired Robots
Biological mechanisms are embraced in mobile robots to interact with their environments. Although existing biologically inspired robots perform well, their performance is limited due to the lack of a flexible spine. A vertebrate spine provides agility, a wide range of motion, balance, and efficiency. This paper proposes a system-level design methodology for a distributed and scalable actuator that mimics a robotic spine in the vertical plane. A modified limb design is introduced that significantly improves the torque capability of the distributed actuator.
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- Award ID(s):
- 1943791
- PAR ID:
- 10392970
- Date Published:
- Journal Name:
- 2021 IEEE International Electric Machines & Drives Conference (IEMDC)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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