A hexapod capable of precision positioning is described. The differences between serial and parallel motion control are presented, and the potential advantages of parallel systems realized as hexapods are highlighted. Actuation options for positioning hexapods are considered in light of a requirement for a high ratio of range to resolution and a need for zero power hold. For positioning of smaller payloads, piezoelectric-based step-and-repeat actuation becomes attractive. The merits of existing and new piezoelectric step-and-repeat actuators are evaluated. A point-and-hold hexapod designated PH1, and its performance, is described, along with several areas identified for possible design improvement. This motivates the development of advanced struts using similar actuation technology. Test results are presented, and a new hexapod, the PH2, is described. This system includes encoder-based feedback control of leg lengths, and a complete software-based user interface and control system. Hexapod test results and performance measurements are presented, and planned future enhancements are described.

Date Published: 14 August 2003
PDF: 14 pages
Proc. SPIE 5054, Smart Structures and Materials 2003: Industrial and Commercial Applications of Smart Structures Technologies, (14 August 2003); doi: 10.1117/12.483893

Published in SPIE Proceedings Vol. 5054:
Smart Structures and Materials 2003: Industrial and Commercial Applications of Smart Structures Technologies
Eric H. Anderson, Editor(s)