DRIVE SYSTEMS INCLUDING SLIDING MODE OBSERVERS AND METHODS OF CONTROLLING THE SAME

At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to generate a voltage command for the motor, a sliding mode observer configured to determine an estimated current for the motor based on the voltage command, determine a difference between the measured current and the estimated current, and determine a switching control vector and an estimator configured to estimate a rotor position based on the switching control vector, the switching control vector being determined based on the difference and adaptive parameters of the sliding mode observer, the controller being further configured to control the motor based at least in part on the estimated rotor position

DRIVE SYSTEMS INCLUDING SLIDING MODE OBSERVERS AND METHODS OF CONTROLLING THE SAME

At least one example embodiment discloses a drive system including a motor including a rotor, the motor configured to receive a measured current, a controller configured to generate a Voltage command for the motor, a sliding mode observer configured to determine an estimated current for the motor based on the Voltage command, determine a difference between the measured current and the estimated current, and determine a Switching control vector and an estimator con figured to estimate a rotor position based on the Switching control vector, the Switching control vector being determined based on the difference and adaptive parameters of the sliding mode observer, the controller being further configured to control the motor based at least in part on the estimated rotor position

Non-Asymptotic State and Disturbance Estimation for a Class of Triangular Nonlinear Systems using Modulating Functions

Dynamical models are often corrupted by model uncertainties, external disturbances, and measurement noise. These factors affect the performance of model-based observers and as a result, affect the closed-loop performance. Therefore, it is critical to develop robust model-based estimators that reconstruct both the states and the model disturbances while mitigating the effect of measurement noise in order to ensure good system monitoring and closed-loop performance when designing controllers. In this article, a robust step by step non-asymptotic observer for triangular nonlinear systems for the joint estimation of the state and the disturbance is developed. The proposed approach provides a sequential estimation of the states and the disturbance in finite time using smooth modulating functions. The robustness of the proposed observer is both in the sense of model disturbances and measurement noise. In fact, the structure of triangular systems combined with the modulating function-based method allows the estimation of the states independently of model disturbances and the integral operator involved in the modulating function-based method mitigates the noise. Additionally, the modulating function method shifts the derivative from the noisy output to the smooth modulating function which strengthens its robustness properties. The applicability of the proposed modulating function-based estimator is illustrated in numerical simulations and compared to a second-order sliding mode super twisting observer under different measurement noise levels.Comment: 24 page

Full- and Reduced-order Model of Hydraulic Cylinder for Motion Control

This paper describes the full- and reduced-order models of an actuated hydraulic cylinder suitable for system dynamics analysis and motion control design. The full-order model incorporates the valve spool dynamics with combined dead-zone and saturation nonlinearities - inherent for the orifice flow. It includes the continuity equations of hydraulic circuits coupled with the dynamics of mechanical part of cylinder drive. The resulted model is the fifth-order and nonlinear in states. The reduced model neglects the fast valve spool dynamics, simplifies both the orifice and continuity equations through an aggregation, and considers the cylinder rod velocity as output of interest. The reduced model is second-order that facilitates studying the system behavior and allows for direct phase plane analysis. Dynamics properties are addressed in details, for both models, with focus on the frequency response, system damping, and state trajectories related to the load pressure and relative velocity.Comment: 6 pages, 6 figures, IEEE conferenc

Position Sensor-less and Adaptive Speed Design for Controlling Brush-less DC Motor Drives

This paper proposes a method for direct torque control of Brushless DC (BLDC) motors. Evaluating the trapezium of back-EMF is needed, and is done via a sliding mode observer employing just one measurement of stator current. The effect of the proposed estimation algorithm is reducing the impact of switching noise and consequently eliminating the required filter. Furthermore, to overcome the uncertainties related to BLDC motors, Recursive Least Square (RLS) is regarded as a real-time estimator of inertia and viscous damping coefficients of the BLDC motor. By substituting the estimated load torque in mechanical dynamic equations, the rotor speed can be calculated. Also, to increase the robustness and decrease the rise time of the system, Modified Model Reference Adaptive System (MMRAS) is applied in order to design a new speed controller. Simulation results confirm the validity of this recommended method

Force Estimation for Teleoperating Industrial Robots

As the energy on the particle accelerators or heavy ion accelerators such as CERN or GSI, fusion reactors such as JET or ITER, or other scientific experiments is increased, it is becoming increasingly necessary to use remote handling techniques in order to interact with the remote and radioactive environment