Exploiting Natural Dynamics in order to Increase the Feasible Static-Wrench Workspace of Robots

Abstract

The reachable workspace of a robot carrying a payload is usually limited by the maximal value of the torque that each actuator can deliver. This results in limiting the zones for the robot to operate with the payload due to a possible division of its static-wrench workspace into several disconnected aspects. In order to increase the reachable workspace areas, this paper proposes to exploit the natural oscillations in dynamics, so that the robot can carry a payload which is out of its feasible static-wrench workspace, i.e. to perform motions between two disconnected aspects, while constraining the torques of the actuators. This is done thanks to the solution of a boundary value problem, which seeks to smartly exchange the gravity potential energy and the kinetic energy in order to connect two desired payload positions, which are placed in two disconnected aspects. Simulations of the suggested approach on a 2-degree-of-freedom robot are performed and show the efficiency of the proposed approach.

Minimizing the Energy Consumption of a Delta Robot by Exploiting the Natural Dynamics

“…In order to define the braking instant t k , we evaluate the dynamic equations grouped in ( 1) for different values of t k on the motion segment valued from t 0 to t k . This is done in order to choose the one which demands less input torques (τ , τ vss ), similar to what it is done in [15] in which the total motion segment from t 0 to t f is divided to solve the BVP. Finally, RK4 represents the numerical integration of the expressions in (4) by using a Runge-Kutta method, and LMUpdate is a function representing the Levenberg-Marquardt updating law based on [13].…”

Exciting Nonlinear Modes of Conservative Mechanical Systems by Operating a Master Variable Decoupling

“…Inspired by biology, researchers have introduced elastic and soft elements into the mechanical design of robotic systems, leading to soft robots [5]. These systems are thought to be especially suited for performing oscillatory tasks, and their expected practical applications include locomotion [6], periodic pick and place [7], and carrying payloads that exceed the static torque limits [8]. Elastic elements may also be optimized to maximize performance [9], [10].…”