Vehicle performance analyzer
US4694687A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1986 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Apr 17, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P1/127
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive accelerometer system for detecting changes in G-forces and for producing a digital count value proportional to such changes. An oscillator-driven capacitive transducer of a unique design produces a voltage variation whose amplitude and frequency characteristics are a function of the direction and magnitude of the applied G-forces. The transducer itself comprises a pair of spaced-apart parallel plates disposed on opposite sides of a beam-supported movable plate which responds to changes in acceleration forces. The modulated signal is then demodulated and applied by a semiconductor switch actuated by a pulse from a microprocessor to a voltage-controlled current source. The current source varies the discharge rate of a precision capacitor. When the voltage on the capacitor drops to a predetermined threshold, an interrupt signal is presented to the microprocessor which had been counting one microsecond pulses from its internal clock during the period between the actuation of the semiconductor switch and the generation of the interrupt. The count is then inversely proportional to the shift in capacitance of the transducer which, in turn, is proportional to the G-forces appl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.