Aerospace: Helicopter sensor

Gyro finds the perfect balance

Who

Plymouth-based Silicon Sensing is to provide a miniature precision micro-electro-mechanical systems gyro to Futaba, a leading Japanese manufacturer of remote control model helicopter electronics, for use in its next-generation servo-controllers.

Technology

The PinPoint gyro was chosen for its combination of tiny footprint (6x5mm), ultra-low power consumption (12mW) and wide measurement range (900°/s). Silicon Sensing said that compared to gyros available to the remote control model helicopter market less than two years ago, PinPoint delivers the same function and performance in a package that is under 1/100th the size and weight, draws less than 1/10th of the power and is 1/3rd of the cost. Its performance brings improved endurance and precision control to a wide range of aircraft.

Silicon Sensing said that PinPoint is the only MEMS gyro to use a fully balanced vibrating silicon ring, whereas others use various forms of simple open-loop vibrating mass structures. The 3mm-diameter balanced ring of the gyro, which resonates at 22kHz in a closed-loop control system, can be thought of as an infinite number of tuning forks integrated to create a fully balanced vibrating circular structure. This provides unrivalled rate output stability over time, temperature, vibration and shock for a MEMS gyro in its class.

Application

The yaw rate information from the gyro will be used by the Futaba controller to automatically stabilise the helicopter’s heading by controlling the tail rotor, thus reducing pilot workload and allowing him/her to concentrate on flying the aircraft. It is available in two surface mount configurations, designated CRM100 and CRM200, which allows full yaw, pitch and roll control to be achieved on a single small printed circuit board assembly.

Eric Whitley, business development executive at Silicon Sensing, said: “Several  low-cost gyros have been launched recently with impressive claims but these have left the designer disappointed with the real-world performance delivered. The difference with our MEMS gyros is in our patented balanced resonating ring sensor design which is common across all Silicon Sensing’s gyros. This design is proven to provide a reliable yaw rate signal even under quite severe vibrations.”