Sensible Sensing

Six-axis force/torque (F/T) sensors measure force and torque in many applications, including electrical and mechanical assembly, product testing, and robot material handling. The sensors help verify part insertion, maintain constant force during buffing, polishing, and deburring, and collect force information for lot testing and statistical process control (SPC). F/T sensors need high-speed data outputs and must work with a variety of bus formats such as PCI and USB. A recent development by ATI Industrial Automation called DAQ F/T integrates sensors directly into desktop and laptop computers using off-the-shelf data-acquisition (DAQ) cards. The result: higher data speeds, easier installation, and flexibility in bus selection and operating systems. A conventional sensor system consists of a transducer, high-flex cable, and a controller to convert strain-gage input to force and torque values. Output is sent to a computer or robot controller using serial, analog, or a customized bus controller. Serial communications are typically slow, and analog output must be converted to digital format. Customized bus controllers are fixed to only one bus format so that improvements in resolution, data speed, or format change requires an expensive upgrade. Because of this, customized bus controllers are only developed after large technology improvements are made over an 8 to 12-year span. By contrast, the DAQ F/T lets users keep up with technology improvements by using off-the-shelf DAQ cards. DAQ F/Ts modify strain-gage signals from transducers and send them to a DAQ card which controls resolution and data speed. These cards change their hardware and software with new bus formats and operating systems, thus keeping the DAQ F/T updated to fit any desktop and laptop computer on the market. The six-axis DAQ F/T system consists of a transducer, high-flex cable, interface board, power supply, DAQ card, and software tools. A proprietary interface card on or near the transducer produces