QUBIKtm IMU

The QUBIKtm Inertial Measurement Unit is a magnetically levitated cube and can be purchased for $100 each in quantities of 1,000. The basic system has three orthogonal linear and three orthogonal angular closed loop accelerometer servo's using variable capacitance detection with electromagnetic restoring force. There are eighteen permanant magnets embedded into a hollow cube. The magnets are arranged in linear parallel orthogonal arrays. The hollow proofmass weighs 0.1 grams. The finished assembly of the proofmass including all 18 magnets weighs 1.1 grams. The entire surface of the proofmass makes up one side of 36 variable capacitances or six variable capacitances per each side of the cube that are used to determine the orientation of the proofmass in side the cartesian coordanate of the inner housing cavity. The inner housing cavity has electromagnets in a face to face relationship with the permanant magnets on the proofmass that are selectrivlety used by the electronics to push or pull on the proofmass to keep the variable capacitance summed signals at virtual ground. The electronically processed capacitance output signals are selectively coupled into the respective linear or angular servo loop. The summation of the capacitance outputs is a virtual ground when the proofmass is centered inside its cavity. There is an intergrator stage in the electronics so that at DC the gain is essentially the open loop op-amp or about one million. The gain drops off as the frequency increaces until the notch frequency of the servo loop that matches the electromagntic spring resonance of the system. Angular gyroscopic rate is generated by injecting an AC singal into one of the servo loops. This sets up and AC dither oscillation of the proofmass about the first axis. Rotating the entire system about a second axis will produce an AC gyroscopic precession about the third axis. The photo below shows a proofmass assembly with magnets embedded into it and two rows of the hollow electroformed proofmass without magnets. 

The photo above is QUBIKtm Inertial Measurement Unit (IMU): magnetically levitate cube 6 DOF accelerometer built under a Small Business Innovative Research (SBIR)contract with the Misille Defence Agnecy (MDA)

The figure below is the Solid Works model of the QUBIKtm IMU Outer assembly.

The figure below is the exploded view Solid Works model of the QUBIKtm IMU Outer assembly.

The figure below shows a Solid Works model exploded view of the QUBIKtm IMU Inner Cube sensor assembly