A Simple Linear Velocity Estimator for High-Precision Motion Control

High-quality low speed motion control calls for precise position and velocity signals. However, velocity estimation based on simple numerical differentiation from the only position measurement may be very erroneous, especially in the low-speed regions. A simple linear velocity estimator is proposed based for high-quality instantaneous velocity estimation, on position measurements only. The proposed estimator is constructed based on the fact that velocity belongs to the chain of kinematic quantities: position and velocity, and numerical integration can provide more stable and accurate results than numerical differentiation in the presence of noise. The main attraction of the new algorithm is that it is very effective as well as in low-speed ranges, high robustness against noise, and easy to implement with simple computation. Both extensive simulations and experimental tests have been performed to verify the effectiveness and efficiency of the proposed approach.