RobEcolo: Optimal Design of a Wooden Five-Bar Mechanism

Abstract

Eco-design of robots has almost never be en explored in the past. This work investigates the potential of using bio-sourced materials, which have almost no environmental impact, instead of metals for robot design. Also, wood is one of the best candidates because of its interesting mechanical properties. However, wood performance / dimensions vary with the atmospheric conditions / external solicitations. Thus, it is challenging to design a stiff and accurate wooden industrial robot. Therefore, the objective of this paper is to describe a new design methodology leading to the design a wooden five-bar mechanism reliable in terms of accuracy and stiffness. The design optimization problem is solved in cascade. The first optimization process proposes to use a control-based design approach in order to compute the optimal primary geometric parameters of the robot (lengths of the links). This approach takes into account the sensor-based controller performance during the design phase. The second optimization process deals with the issue of the variability of the wood mechanical performance. It is based on a reliable topology optimization approach and allows for finding the shape of the robot links for which the impact of this variability in terms of deformation is minimized. Theoretical developments are described, solved and the obtained results allowed the prototyping of an industrial wooden five-bar mechanism.

R-Min: a Fast Collaborative Underactuated Parallel Robot for Pick-and-Place Operations

“…In Table I, the lengths, inertia and positions of centre of mass extracted from CAD are provided. The links lengths have been chosen such that, if the points O i2 , O i3 and P (i = 1 or 2) were aligned, the robot kinematics would be equivalent to the one of the five-bar mechanisms designed in [28], [29].…”

Design of an Accurate and Stiff Wooden Industrial Robot: First Steps Toward Robot Eco-sustainable Mechanical Design

“…The performance to be achieved by the wooden industrial robot has been fixed by our partners in the scope of the project RobEcolo [31]. They are detailed in Tab.…”

“…The paper is an extended version of [31] where we provide results on the deformation under loading of a wooden industrial robot prototype, and we develop several sensorbased control approaches and experimentally compare their performance in terms of robot accuracy, A first discussion about the obtained decrease of the environmental impact when using wood for industrial robot design was provided.…”