Vibration Suppression Control based on Final State Control Considering Convergence Time and Inertia Variation for Industrial Robot

Abstract

Industrial robots require high-speed and high-precision motion for improvements in productivity and product quality. However, high-speed motion excites residual vibration because the joint axis of the industrial robot has axial torsion. In addition, the inertia moment of the industrial robot is changed by the end-effector tool. Therefore, robust vibration suppression control is required. However, achieving both robust vibration suppression control and high-speed motion control is difficult. This paper proposes a new final state control method that considers the convergence time and inertia variation for an industrial robot. The proposed method applies final state control to the entire motion control system of each joint. To achieve the desired convergence time for the end-effector, the final state control profile is redesigned by using a proposed flowchart. The effectiveness of the proposed method is confirmed by a numerical simulation and an experiment using a 3-degree-of-freedom robot manipulator.

Disturbance Modeling based on Fourier Series for Precise Reaction Force Estimation in Semicircular Linear Motor

“…AIC is a quantitative comparison criterion based on information content. AIC is utilized to decide the optimal order of the Fourier series in (13), (14), and (15) (30) . The derived order does not depend on the characteristics of the plant system because AIC derives only an optimal order for compensation, not a true value.…”

“…Finally, the optimal model is selected by comparing the AIC values. Various models related to (13), (14), and (15) that have various Fourier series orders are considered and AIC is calculated for each order. The order that minimizes AIC represents the optimal order.…”

“…σ 2 (ω) denotes the variance of data at each angular velocity. D(ω|k) stands for the approximation formula of A, shown in (13). Then, log likelihood function l(k) is represented as (20) l(k) = n u=1 log f (ω u , A u |k).· · · · · · · · · · · · · · · · · · · · · · (20)…”

“…In conventional methods, the estimation error is compensated by a model of friction force of each system (11) (12) . In addition, inverse dynamics and observer based compensation are also helpful for industrial systems (13) (14) . In fast precise positioning systems, feedforward compensation reduces positioning deterioration caused by mechanical vibration and friction.…”

Recent advances and outlook in industrial instrumentation and mechatronics control

“…The disturbance observer (DOB) is often termed as the pronoun of motion control technology. Hence, majority of papers related to motion control in IEEJ J. IA are related to DOB .…”