Browsing by Subject "Error compensation"
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Item Open Access Adaptive filtering for non-gaussian stable processes(IEEE, 1994) Arıkan, Orhan; Çetin, A. Enis; Erzin, E.A large class of physical phenomenon observed in practice exhibit non-Gaussian behavior. In this letter, a-stable distributions, which have heavier tails than Gaussian distribution, are considered to model non-Gaussian signals. Adaptive signal processing in the presence of such a noise is a requirement of many practical problems. Since direct application of commonly used adaptation techniques fail in these applications, new algorithms for adaptive filtering for α-stable random processes are introduced.Item Open Access Evaluation of solid-state gyroscope for robotics applications(Institute of Electrical and Electronics Engineers, 1995-02) Barshan, B.; Durrant-Whyte, H. F.he evaluation of a low-cost solid-state gyroscope for robotics applications is described. An error model for the sensor is generated and included in a Kalman filter for estimating the orientation of a moving robot vehicle. Orientation eshation with the error model is compared to the performance when the error model is excluded from the system. The results demonstrate that without error compensation, the error in localization is between 5-15"/min but can be improved at least by a factor of 5 if an adequate error model is supplied. Like all inertial systems, the platform requires additional information from some absolute position-sensing mechanism to overcome long-term drift. However, the results show that with careful and detailed modeling of error sources, inertial sensors can provide valuable orientation information for mobile robot applications.Item Open Access Inertial navigation systems for mobile robots(Institute of Electrical and Electronics Engineers, 1995-06) Barshan, B.; Durrant-Whyte, H. F.A low-cost solid-state inertial navigation system (INS) for mobile robotics applications is described. Error models for the inertial sensors are generated and included in an Extended Kalman Filter (EKF) for estimating the position and orientation of a moving robot vehicle. Two Merent solid-state gyroscopes have been evaluated for estimating the orientation of the robot. Performance of the gyroscopes with error models is compared to the performance when the error models are excluded from the system. The results demonstrate that without error compensation, the error in orientation is between 5-15"/min but can be improved at least by a factor of 5 if an adequate error model is supplied. Siar error models have been developed for each axis of a solid-state triaxial accelerometer and for a conducting-bubble tilt sensor which may also be used as a low-cost accelerometer. Linear position estimation with information from accelerometers and tilt sensors is more susceptible to errors due to the double integration process involved in estimating position. With the system described here, the position drift rate is 1-8 cds, depending on the frequency of acceleration changes. An integrated inertial platform consisting of three gyroscopes, a triaxial accelerometer and two tilt sensors is described. Results from tests of this platform on a large outdoor mobile robot system are described and compared to the results obtained from the robot's own radar-based guidance system. Like all inertial systems, the platform requires additional information from some absolute position-sensing mechanism to overcome long-term drift. However, the results show that with careful and detailed modeling of error sources, low-cost inertial sensing systems can provide valuable orientation and position information particularly for outdoor mobile robot applications.Item Open Access Robust antiwindup compensation for high-precision tracking of a piezoelectric nanostage(Institute of Electrical and Electronics Engineers Inc., 2016) Liu, P.; Yan, P.; Zhang Z.; Özbay, HitayUltrahigh-precision tracking in nanomanipulations poses major challenges for mechanical design as well as servo control, due to the general confliction between the precision requirement and large stroke tracking. The situation is further complicated by input saturation, which is almost inevitable for microactuators. This paper presents a novel control architecture combining a parallel internal-model-based tracking design and a robust antiwindup control structure, such that asymptotic tracking can be achieved for nanoservo systems in the presence of saturation nonlinearity and model uncertainties. For the augmented system with internal-model dynamics, an I/O-based equivalent representation from control (free of saturation) to system output is derived by incorporating the dead-zone nonlinearity, saturation compensation blocks, as well internal-model units. The robustness condition on the saturation compensator is also derived based on the sector bound criterion and an H∞-optimal design is developed accordingly. The proposed robust antiwindup tracking control architecture is deployed on a customize-designed nanostage driven by a piezoelectric (PZT) actuator, where numerical simulations and real-time experiments demonstrate excellent tracking performance and saturation compensation capability, achieving tracking precision error less than 0.23%.