Gateway Configuration for Rapid Pick-and-Place Operations of 2-Degrees-of-Freedom Parallel Robots

Abstract

This paper presents a new assembling for 2 degrees of freedom (DOF) parallel robots for executing rapid pick-and-place operations with low energy consumption, main objectives of pick-and-place operations. A conventional design of 2-DOF parallel robots is based on five-bar mechanisms. Collisions between links are highly possible, restricting the end-effector workspace and/or increasing the trajectory time to avoid collisions. In this work, an alternative assembling for preventing collision is presented. This novel assembling allows exploring the difference between the four five-bar mechanism congurations for the same position of the end-effector. Some of these congurations yield to lower time and/or lower energy consumption for the same motorization. Firstly, a dynamic model of the robot has been developed using Matlab and Simulink and validated by comparison with the results obtained by ADAMS software. A robust cascade PD regulator for controlling joint coordinates has been tuned providing a high accurate end-effector positioning. Finally, simulation results of 4 congurations are presented for executing controlled manoeuvres. The obtained results demonstrate that the conventional conguration is the worst one in terms of trajectory time or energy consumption and, conversely, the best one corresponds to an uncommonly used conguration. A workspace map where all congurations provide faster manoeuvres has been obtained in terms of Jacobian matrix and mechanism elbows distance. The results presented here allow designing a rapid manipulator for pick-and-place operations.

A new fast nonlinear model predictive control of parallel manipulators: Design and experiments

“…6: Compute the control law of the enhanced fast NMPC controller with feedback gains by using equation (22).…”

“…To improve tracking performance of the 4-DOF VELOCE PKM, the enhanced fast NMPC control law with feedback gains can be expressed as follows Γ = Γ f2 + K P (. )e(k) (22) where Γ f2 denotes the fast NMPC control term given by Equation (25). Further, K P , K I , K D ∈ R n×n are positive definite matrices that represent the feedback gains of the PID control term.…”

“…The proposed approach was directly applied to parallel kinematic manipulators (PKMs). These robots are of growing interest in various fields, such as 3D printing [21], pickand-place [22], laser cutting [23], and even surgical interventions [24]. PKMs are typically characterized by their high precision, high nonlinear dynamics, obtained highspeed singularities, time-varying parameters, and uncertainties [25] [26].…”