Measuring the position of a shaft with both linear and rotary motion is a challenging design problem that usually involves two sensors, one for each axes of motion, and two input ports. Three engineers at MTS Sensors just received a patent (U.S. patent 6,600,310) for a sensor technology that does both, potentially saving engineers cost and complexity in their designs. The sensor is an extension of MTS' Temposonics non-contact position sensor technology, which exploits the capability of a magnetostrictive material to deform under the application of a magnetic field. The sensor works by inducing a sonic wave in a magnetostrictive waveguide through the interaction of a magnetic field from a ring-shaped permanent magnet that moves along the sensor tube and a current—or interrogation—pulse. By measuring the elapsed time for the resulting strain pulse to travel along the waveguide to a detector head, the magnet's absolute position can be determined with high accuracy. This sensor takes the concept a step further by employing a second permanent magnet that is helical in shape. In essence, this second magnet provides a reference position so that the amount of rotation of the linear magnet on the shaft can be determined. A first application for the technology is in automatic manual transmissions. Though that may sound like an oxymoron, automakers, in fact, have been looking at ways to take a standard transmission with clutch pedal and manual shift gear selector and automate the two steps. At least two companies are evaluating MTS's two-magnet magnetostrictive position for sensing both linear and rotary motion of the shift shaft as it moves through an H pattern to select the appropriate gear cluster. Engineers say that the sensor resolution can be up to 2 microns, although a version targeted at lower-cost applications has a resolution on the order of 40 microns.
The engineers and inventors of the post WWII period turned their attention to advancements in electronics, communication, and entertainment. Breakthrough inventions range from LEGOs and computer gaming to the integrated circuit and Ethernet -- a range of advancements that have little in common except they changed our lives.
Neil Fromer is the executive director of the Resnick Institute, a program for energy and sustainability at the California Institute of Technology, working to develop new ideas and research technologies related to providing a sustainable future. He spoke to us about the severity of the current drought in California and how solar energy can help prevent such situations in the future.
From home enthusiasts to workers on the manufacturing floor, everyone's imagination is captured by the potential of 3D printing. Prototyping, spare parts creation, art delivery, human organ creation, and even mass product production are all being targeted as current and potential uses for the technology.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.