Control-Based Design of a Five-Bar Mechanism

ROMANSY 23 - Robot Design, Dynamics and Control

2020

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In the present paper, a control-based design methodology is developed in order to create a DELTA robot with the best accuracy performance for a dedicated controller. The proposed control-based design methodology takes into account the accuracy performance of the controller in the design process to get the optimal geometric parameters of the robot. Three types of controllers are envisaged for the control of the motions of the DELTA robot: leg-direction-based visual servoing, line-based visual servoing and image moment visual servoing. Based on these three controllers, positioning error models taking into account the error of observation coming from the camera are developed. Then, design optimization problems are formulated in order to find the optimal geometric parameters and camera placement for the DELTA robot for each type of controller. Co-simulations of the robots optimized for the three types of controllers are finally performed in order to check the accuracy performance of the three robots.

Section: Positioning Error Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control-Based Design of a DELTA Robot

Zhu

Chriette

ROMANSY 23 - Robot Design, Dynamics and Control

2020

Self Cite

“…For this reason we decided to define a controller based on the observation of the distal links, as in Andreff et al (2007). However, as shown in Briot et al (2015) this controller is not free of singularities, that effect its accuracy performance which that not only depend on the camera localisation and specifications but also on the robot dimensions as shown in Kaci et al (2016). Thus the optimization process must take all this parameters into account.…”

Section: Design Processmentioning

confidence: 99%

Design of a Wooden Five-Bar Mechanism

Kaci

ROMANSY 22 – Robot Design, Dynamics and Control

Boudaud

et al. 2018

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Eco-design of robots is a field of research which has been rarely explored in the past. In order to considerably decrease the environmental impact of robot during the design phase, metal or carbon composite parts can be replaced by bio-sourced materials, such as wood. Indeed, wood has interesting mechanical properties, but its performance / dimensions will vary with the atmospheric conditions / external solicitations and with the conditions in which trees have grown. This paper deals with the design of a stiff and accurate wooden five-bar mechanism. First, a control-based design problem is formulated. This problem aims at finding the optimal parameters of the robot, taking into account the nature of the desired control (sensor-based control). Then, reliable topology optimization methodology is proposed, taking into account the variability of the wood performance and that will allow the definition of robot architectures (shape of the links) for which the impact of this variability in terms of deformation is minimal. Finally, the optimal design variables are given and are used for the realisation of industrial prototype of a wooden five-bar mechanism.

“…• In order to ensure the robot accuracy even with the variability in the wooden link dimensions, sensor-based controllers could be used [10]. However, as shown in [11], positioning accuracy of sensor-based controllers (obviously) depends of the number and types of sensors that are used for the robot control, but also, in certain cases, of the robot geometric parameters [12]. Therefore, the robot design process must take into account performance criteria coming from usual physical properties [13] but also from the type of controller that will be implemented on the robot.…”

Section: Introductionmentioning

confidence: 99%

“…It should be mentioned that expressions (10) and (11) are approximated functions obtained thanks to a Taylor series expansion at the order two of the expression of the robot end-effector deformation u e with respect to the components of the vector π E [14]. We tested their validity and our results shown that, for the mechanical parameters of the acetylated beech, the error of approximation is lower than 10 %.…”

mentioning

confidence: 97%

RobEcolo: Optimal Design of a Wooden Five-Bar Mechanism

Kaci

Volume 5A: 42nd Mechanisms and Robotics Conference

Boudaud

et al. 2018

Self Cite

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.