Suppression of performance degradation of reconfigurable robot by quantization error based on quantization error observer

Generally, the ΔΣ modulator is widely used to suppress the influence of the quantization error. This method can shape the quantization error by a differentiator and shift its power to the high frequency range. From this reason, the influence of the quantization error can be suppressed in the low frequency range, where the main components of the control signal should have larger power. However, the quantization error is excessively amplified in higher frequencies, so performance degradation and/or destabilization of the control system may occur. On the other hand, the quantization error observer (QEOB), which is our proposed method, can shape it through a high-pass filter. Thereby, QEOB can shape the quantization error without excessive amplification in the high frequency range. Finally, we apply QEOB to a 2-link reconfigurable robot system and the effectiveness of the proposed method is confirmed by the simulation.