Development of a low cost motion actuator as an artificial joint for the physically handicapped person

Norbert C. Cheung

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

1 Citation (Scopus)


Acad. Publ., World Publ. Corp. Traditionally, actuators for hinge motions are constructed from d.c. motors and reduction gears. This kind of motion actuator is simple to control, but it has a complex mechanical structure, and is it costly, expensive and requires maintenance. In this paper, a low-cost direct-drive motion hinge actuator based on variable reluctance principle has been developed. Variable reluctance actuator has a simple and robust structure, and it is widely used as low cost switching actuator in many applications. However, it has not gain widespread acceptance as a proportional actuator due to its inherent nonlinear control characteristics. In this paper, the problem is overcome by using a novel control strategy based on 21 nonlinear lookup table. The paper first describes the design, construction, fabrication and operating principle of the variable reluctance actuator. After the variable reluctance actuator has been fabricated, essential electrical and mechanical characteristics are measured. Then, a novel nonlinear control algorithm for the trajectory tracking of this actuator has been proposed. The proposed algorithm is implemented on a digital signal processor to control the motion of variable reluctance actuator in trajectory profile following mode. Results from the implementation show that the vaiiable reluctance actuator can be controlled with high degree of speed and accuracy. This makes the actuator ideal for hinge motions of artificial limbs, and as a motion aid for the physically handicapped person.
Original languageEnglish
Title of host publicationProceedings - IPEMC 2000
Subtitle of host publication3rd International Power Electronics and Motion Control Conference
Number of pages6
ISBN (Electronic)780003464X, 9787800034640
Publication statusPublished - 1 Jan 2000
Event3rd International Power Electronics and Motion Control Conference, IPEMC 2000 - Beijing, China
Duration: 15 Aug 200018 Aug 2000


Conference3rd International Power Electronics and Motion Control Conference, IPEMC 2000


  • Artificial joint
  • Nonlinear control
  • Variable reluctance actuator

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Control and Systems Engineering
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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