Abstract: A state estimation device receives, as inputs, an output from a target system and a nonlinear model that is a modeled target system, and estimates a state of the target system by using an extended Kalman filter. The nonlinear model includes a nonlinear continuous-time state equation. The device includes a state-and-error estimation unit that, on the basis of an observation equation of the nonlinear model, obtains an estimated state value and an estimated value of an error covariance matrix of the estimated state value, the estimated state value being indicative of an estimated state of the target system at a certain time point. The state estimation device also includes state-equation discretization circuitry that obtains a discrete-time state equation by discretizing the nonlinear continuous-time state equation on the basis of the estimated state value at this time point, by using a quadratic or higher-order integration technique.

Abstract: A system identification device includes: a direct feedthrough term identification unit that receives an impulse response of a dynamic system; a block Hankel matrix generation unit; a singular value decomposition unit that, by singular value decomposition of the block Hankel matrix, outputs a first orthogonal matrix, a second orthogonal matrix, and a singular value; a system dimension determination unit that, on the basis of the first orthogonal matrix, second orthogonal matrix, singular value, and search range, identifies a system matrix other than a direct feedthrough term, and from a comparison of the actual system characteristics and system characteristics calculated on the basis of the system matrix and direct feedthrough term, determines the system dimension; and a system matrix identification unit that identifies a system matrix other than the direct feedthrough term on the basis of the first orthogonal matrix, second orthogonal matrix, singular value, and system dimension.

Abstract: A hemispherical resonator gyro includes: a vibration mode shape extractor to extract, based on sine and cosine wave signals corresponding to an actuator drive frequency and radial displacement of a hemispherical resonator, a vibration mode shape excited in the hemispherical resonator; a drive frequency corrector to cause, based on a resonance phase characteristic of the hemispherical resonator, the actuator drive frequency to match resonance frequency of the hemispherical resonator; a nodal quadrature vibration controller to generate, based on a vibration amplitude of a nodal quadrature vibration and azimuth orientation of wave antinode of a resonance mode, an actuator DC drive signal to suppress the nodal quadrature vibration; and a resonance controller to generate an actuator AC drive signal to control the vibration amplitude to be a constant value, and detect a rotational angle in an angle measurement axis direction from the azimuth orientation of wave antinode of the resonance mode.

Abstract: A system identification device includes: a direct feedthrough term identification unit that receives an impulse response of a dynamic system; a block Hankel matrix generation unit; a singular value decomposition unit that, by singular value decomposition of the block Hankel matrix, outputs a first orthogonal matrix, a second orthogonal matrix, and a singular value; a system dimension determination unit that, on the basis of the first orthogonal matrix, second orthogonal matrix, singular value, and search range, identifies a system matrix other than a direct feedthrough term, and from a comparison of the actual system characteristics and system characteristics calculated on the basis of the system matrix and direct feedthrough term, determines the system dimension; and a system matrix identification unit that identifies a system matrix other than the direct feedthrough term on the basis of the first orthogonal matrix, second orthogonal matrix, singular value, and system dimension.

Abstract: A system identification device identifies a linear discrete-time system using a recursive method with respect to each dimension belonging to a designated search range of a system dimension, calculates a system output obtained when actual input data for identification is applied to a linear discrete-time system corresponding to each dimension as a system characteristic, determines a minimum dimension from among dimensions at which a norm distribution of sum of squares of errors in a time domain of the system output and actual output data for identification of the dynamic system is less than or equal to a threshold value, to be a system dimension n, and identifies a system matrix of the linear discrete-time system based on input and output vectors of the dynamic system, and a state vector generated using the determined system dimension.

Abstract: A hemispherical resonator gyro includes: a vibration mode shape extractor to extract, based on sine and cosine wave signals corresponding to an actuator drive frequency and radial displacement of a hemispherical resonator, a vibration mode shape excited in the hemispherical resonator; a drive frequency corrector to cause, based on a resonance phase characteristic of the hemispherical resonator, the actuator drive frequency to match resonance frequency of the hemispherical resonator; a nodal quadrature vibration controller to generate, based on a vibration amplitude of a nodal quadrature vibration and azimuth orientation of wave antinode of a resonance mode, an actuator DC drive signal to suppress the nodal quadrature vibration; and a resonance controller to generate an actuator AC drive signal to control the vibration amplitude to be a constant value, and detect a rotational angle in an angle measurement axis direction from the azimuth orientation of wave antinode of the resonance mode.