Trajectory Optimization of Robots With Regenerative Drive Systems: Numerical and Experimental Results

Abstract

We investigate energy-optimal control of robots with ultracapacitor based regenerative drive systems. Based on a previously introduced framework, a fairly generic model is considered for the robot and the drive system. An optimal control problem is formulated to find point-to point trajectories maximizing the amount of energy regenerated and stored in the capacitor. The optimization problem, its numerical solution and an experimental evaluation are demonstrated using a PUMA 560 manipulator. A comprehensive experimental setup was prepared to evaluate power flows and energy regeneration. Tracking of optimal trajectories was enforced on the robot using a standard robust passivity based control approach. Experimental results show that when following optimal trajectories, a reduction of about 13% in energy consumption can be achieved for the conditions of the study.

Dynamic modeling and power optimization of a 4RPSP+PS parallel flight simulator machine

“…The importance of this concept is testified by abundant literature including both theoretical and experimental studies for enhancing the energy efficiency in manipulators and automatic machines [23]. The main approaches to achieve this goal are: (1) the proper choice of the manipulator type, [24] (2) designing lightweight manipulators with lower inertia, [25,26] (3) optimization of manipulator structure, [27] using regenerative drive systems, [28,29] trajectory planning and motion planning, [30,31,32] applying redundancy on non-redundant manipulators, [33,34,35,36] optimizing location of the task with respect to the base of the manipulator [37,38] and joint force/torque minimization [13,39,40] and introduction of complaint or elastic elements into the manipulator [41,42].…”

Energy-saving optimization method for point-to-point trajectories planned via standard primitives in 1-DoF mechatronic systems

“…Finally, the mixed approach considers hardware and software modifications of the mechatronic system working in synergy. This is the case of trajectory optimization in systems equipped with regenerative drives to maximize the energy regenerated and stored in the capacitors [31,32]. Further methods use compliant elements inserted, in parallel or in series, to the actuators, in combination with a proper trajectory optimization to exploit the free vibration response of the system performing cyclic tasks [33][34][35][36].…”

An Overview of Energy-Optimal Impedance Control of Cooperative Robot Manipulators

“…Robots with on-board, finite energy storage are prevalent in electric vehicles, powered human assistive devices, aerospace vehicles, etc. [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11].…”

“…Energy regeneration is defined here as the ability to transfer energy back to the system's power source during motion tasks. Energy-aware control in robotics, particularly concerning energy regeneration, has gained a broad research interest recently [1], [2], [8], [9], [6]. Ultracapacitors have been used in addition to or instead of batteries as energy storage elements in regenerative motion systems.…”