Petri Kuosmanen

A practical millimeter-wave radar calibration target

A simple rectangular-plate millimeter-wave radar calibration target gives RCS values ranging from hundreds to thousands of square meters. This enable tests over extended ranges and with equipment having modest output power. Precise mechanical alignment mechanisms and an optical sight are mandatory, due to the narrow beamwidth. Absorber collars provide an easy way of adjusting the actual RCS according to specific mission requirements, and effectively reduce edge-diffraction effects. The measured V-band calibration uncertainty was less than 0.5 dB, and the pointing resolution was better than 0.05/spl deg/.

Analysis of sensor platform dynamics in ground vehicle

A vehicular platforms dynamical behavior is analyzed as a basis for designing a laboratory test apparatus and an associated 2-dimensional orthogonal stabilizer. The test track caused inclination in the front direction to vary from -6.5deg to 7.2deg and from -5.5deg to 5.0deg in the side direction. The maximum angular rate was 19.8 plusmn 0.1deg/s in the front direction within a bandwidth of 0-2.5 Hz and 14.4 plusmn 0.05deg/s in the side direction. The platforms natural frequency in the front direction was found to be 0.8-1.0 Hz. In the side direction the most significant rate values appeared within 0-4 Hz but the natural frequency did not wake. Inclination measurements were based on sensor fusion where the basic model of stochastic Kalman filtering was applied

Ball balancing system: an educational device for demonstrating optimal control

The basic ideas of feedback and control are not difficult to understand. However it is an interesting challenge to demonstrate control techniques in an entertaining and attractive way. The ball balancing device presented in this paper was developed to be used as a research and exhibition device. The solution of the control design problem is based on the physical model of the process and modern control theory. Linear quadratic regulator is used to control the process and Kalman filter is used to estimate the state of the ball. Machine vision is applied in the position measurement of the ball and linear servo motors are used as actuators.