to the slide ram the piezo electric drive motor provides for smoother operation and more accurate and repeatable positioning than has heretofore been possible in a linear positioning stage in addition the piezo electric motor significantly reduces the overall size of the positioning stage in comparison to prior art designs using external driving devices although the piezo electric motor is the preferred method of driving the carriage assembly the present invention positioning stage is not limited to this motor but rather may be used with conventional externally mounted driving devices such as linear motors actuators ball and lead screws and belt drive mechanisms not shown the linear stage assembly 10 additionally incorporates a device for tracking the movement of the carriage assembly 14 relative to the ram 16 preferably the tracking device is a digital encoder 26 which like the piezo electric motor 20 is also integrated into the carriage assembly the digital encoder is operably connected to the slide ram by means of a sensing strip not shown similar to the motor drive strip 24 containing a series of calibrated markings which may be sensed by the read head of the encoder although a digital encoder is the preferred means of tracking carriage movement relative to the slide ram other position location devices such as optical encoders whether mounted internally or externally of the carriage are also suitable both the digital encoder and the piezo electric drive motor may be placed axially in line at opposite ends of the carriage assembly 14 or may be located side by side or may be placed at any convenient position within the carriage assembly the positioning shown in.