A low-cost alternative is the Mini-hexapod from Picard Industries, Albion, N.Y. (picard-industries.com). It combines six high-resolution stepper motors from Haydon Switch & Instrument Inc.

(hsi-inc.com), dedicated drive electronics, and a Windows user interface into a kinematics platform with 0.00005-in. repeatability. The pod handles 5-lb loads, and can move 1 in. in the X, Y, and Z axes, and rotate 20° about the X, Y, and Z axes. Springs keep all moving parts in compression and minimize backlash, keeping it under 0.1 m. The unit can be programmed to go through 8,000 steps and it can execute up to 500 steps/sec.