A Simulation-Driven Graph Grammar Method for the Automated Synthesis of Passive Dynamic Brachiating Robots

2015 ◽  
Author(s):  
Fritz R. Stöckli ◽  
Kristina Shea
Keyword(s):  
Dynamic Simulation ◽  
Dynamic Systems ◽  
Design Method ◽  
Automated Design ◽  
Graph Grammar ◽  
Automated Synthesis ◽  
Continuous Contact ◽  
Grammar Rules ◽  
System Properties ◽  
Tree Branch

Topologic configurations of passive dynamic locomotion robots are usually designed manually by human designers and often bio-inspired. However, it is possible that, among the large number of possible configurations, some valid solutions to the problem exist that are potentially superior to existing solutions and, at the same time, different from bio-inspired or otherwise intuition-inspired configurations, and thus not likely discovered without an automated design method. This paper addresses the problem of the automated design of passive dynamic systems in general by introducing a graph grammar based method that integrates dynamic simulation to evaluate and evolve configurations. In particular, the method is shown to find different, new solutions to the problem of the design of two-dimensional passive dynamic continuous contact brachiating robots. Brachiating is the swinging locomotion of primates moving from one tree branch to the next. The presented graph grammar rules preserve system properties among robot topologies, which makes it possible to maintain the necessary symmetry of the brachiating configurations. A separation of parametric optimization and topologic synthesis actions is proposed for the synthesis of passive dynamic systems. Compared to research on automated synthesis of robot topologies that use dynamic simulation to evaluate actuated and controlled robotic systems, this paper contributes a method to automatically generate alternative topologies for passive dynamic systems, which do not draw energy from a power source.

Automated Synthesis of Passive Dynamic Brachiating Robots Using a Simulation-Driven Graph Grammar Method

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Fritz Stöckli ◽  
Kristina Shea
Keyword(s):  
Dynamic Simulation ◽  
Dynamic Systems ◽  
Computational Design ◽  
Automated Design ◽  
Graph Grammar ◽  
Robotic Systems ◽  
Design Synthesis ◽  
Continuous Contact ◽  
Cyclic Motion ◽  
Grammar Rules

Passive dynamic systems have the advantage over conventional robotic systems that they do not require actuators and control. Brachiating, in particular, involves the swinging motion of an animal from one branch to the next. Such systems are usually designed manually by human designers and often are bio-inspired. However, a computational design approach has the capability to search vast design spaces and find solutions that go beyond those possible by manual design. This paper addresses the automated design of passive dynamic systems by introducing a graph grammar-based method that integrates dynamic simulation to evaluate and evolve configurations. In particular, the method is shown to find different, new solutions to the problem of the design of two-dimensional passive, dynamic, continuous contact, brachiating robots. The presented graph grammar rules preserve symmetry among robot topologies. A separation of parametric multi-objective optimization and topologic synthesis is proposed, considering four objectives: number of successful swings, deviation from cyclic motion, required space, and number of bodies. The results show that multiple solutions with varying complexity are found that trade-off cyclic motion and the space required. Compared to research on automated design synthesis of actuated and controlled robotic systems, this paper contributes a new method for passive dynamic systems that integrates dynamic simulation.

A study on the grammatical construction of function structures

2005 ◽  
Vol 19 (3) ◽  
pp. 139-160 ◽  
Author(s):  
PRASANNA SRIDHARAN ◽  
MATTHEW I. CAMPBELL
Keyword(s):  
Automated Reasoning ◽  
Black Box ◽  
Graph Grammar ◽  
Functional Information ◽  
Customer Requirements ◽  
Conceptual Engineering ◽  
Grammatical Construction ◽  
Grammar Rules ◽  
Interactive User ◽  
Function Structures

Function structures are used during conceptual engineering design to transform the customer requirements into specific functional tasks. Although they are usually constructed from a well-understood black-box description of an artifact, there is no clear approach or formal set of rules that guide the creation of function structures. To remedy the unclear formation of such structures and to provide the potential for automated reasoning of such structures, a graph grammar is developed and implemented. The grammar can be used by a designer to explore various solutions to a conceptual design problem. Furthermore, the grammar aids in disseminating engineering functional information and in teaching the function structure concept to untrained engineers. Thirty products are examined as a basis for developing the grammar rules, and the rules are implemented in an interactive user environment. Experiments with student engineers and with the automated creation of function structures validate the effectiveness of the grammar rules.

Topology Optimization of Rigid-Body Systems Considering Collision Avoidance

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Fritz Stöckli ◽  
Kristina Shea
Keyword(s):  
Topology Optimization ◽  
Rigid Body ◽  
Collision Avoidance ◽  
Optimization Problems ◽  
Computational Design ◽  
Optimization Method ◽  
The Body ◽  
Graph Grammar ◽  
Automated Synthesis ◽  
Inertia Properties

Abstract Passive dynamic mechanisms can perform simple robotic tasks without requiring actuators and control. In previous research, a computational design method was introduced that integrates dynamic simulation to evaluate and evolve configurations of such mechanisms. It was shown to find multiple solutions of passive dynamic brachiating robots (Stöckli and Shea, 2017, “Automated Synthesis of Passive Dynamic Brachiating Robots Using a Simulation-Driven Graph Grammar Method,” J. Mech. Des. 139(9), p. 092301). However, these solutions are limited, since bodies are modeled only by their inertia properties and thus lack a shape embodiment. This paper presents a method to generate rigid-body topologies based on given inertia properties. The rule-based topology optimization method presented guarantees that the topology is manifold, meaning that it has no disconnected parts, while still connecting all joints that need to be part of the body. Furthermore, collisions with the environment, as well as with other bodies, during their predefined motion trajectories are avoided. A collision matrix enables efficient collision detection as well as the calculation of the swept area of one body in the design space of another body by only one matrix–vector multiplication. The presented collision avoidance method proves to be computationally efficient and can be adopted for other topology optimization problems. The method is shown to solve different tasks, including a reference problem as well as passive dynamic brachiating mechanisms. Combining the presented methods with the simulation-driven method from Stöckli and Shea (2017, “Automated Synthesis of Passive Dynamic Brachiating Robots Using a Simulation-Driven Graph Grammar Method,” J. Mech. Des. 139(9), p. 092301), the computational design-to-fabrication of passive dynamic systems is now possible and solutions are provided as STL files ready to be 3D-printed directly.

Dynamic Simulation Tests on Influencing Factors of Deep Tilling Plow Working Performance

2011 ◽  
Vol 219-220 ◽  
pp. 441-445
Author(s):  
Xiu Chi Hu ◽  
Lan Xia Zheng ◽  
Lei Jia ◽  
Xin Song
Keyword(s):  
Dynamic Simulation ◽  
Surface Soil ◽  
Design Method ◽  
Optimal Level ◽  
Soil System ◽  
Factors Influencing ◽  
Experimental Design Method ◽  
Dynamic Simulation Model ◽  
Working Performance ◽  
System Dynamic Simulation

A plow surface-soil system dynamic simulation model was established, through MathCAD and ANSYS/LS-DYNA, on which the dynamic simulation tests were carried out by experimental design method. The discipline and mechanism about forming parameters of guiding curve and the plow working factors influencing on two targets, traction resistance and turn performance, were discussed and the factors optimization was made. The results show that tangent angle of guiding curve endpoints has a remarkable influence on two targets; in addition, it is benefit for reducing traction resistance and enhancing turn performance when the angle is large. Under the optimal condition, traction resistance is 4.40kN and turn performance reaches the optimal level 8.0.

Geometric Reasoning on Molding Planning for Multishot Mold Design

2006 ◽  
Vol 6 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Zhou-Ping Yin ◽  
Han Ding ◽  
You-Lun Xiong
Keyword(s):  
Design Method ◽  
Automated Design ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Assembly Planning ◽  
Material Objects ◽  
Mold Design ◽  
Assembly Model ◽  
Contact Graph ◽  
Planning Approach

This paper presents algorithms for automated design of multishot molds for manufacturing multimaterial or multicolor objects, and focuses on molding planning that determines a sequence of mold stages required to produce the desired object. By modeling a multimaterial object as an assembly of homogenous components, a geometric reasoning approach is proposed to generate feasible or practical mold stage sequences by combining the assembly planning approach and the two-plate mold design method. First, a graph-based assembly model, namely the attributed contact graph, is derived from the B-rep models of the constituent components of the gross object by detecting and representing all the contacts between mating components explicitly. Then, all feasible mold stage sequences, represented by an AND/OR graph, are generated by reasoning on geometric constraints due to the demoldability and connectedness requirements using an assembly-by-disassembly strategy. Depending on its demoldability, each component is to be made by one of the three basic molding strategies with varied mold stages and/or mold pieces. To narrow the choice, an optimal or practical molding plan is searched from the feasible molding plans according to some criteria such as the number of mold stages, the number of side cores, and flatness of the parting line. Finally, starting from the last mold stage, mold pieces for each mold stage of the selected molding plan are constructed recursively. The feasibility of the proposed algorithms is demonstrated through an implemented prototypical system, which has been tested successfully with various multi-material objects.

scholarly journals Using a graph grammar system in the finite element method

2013 ◽  
Vol 23 (4) ◽  
pp. 839-853 ◽  
Author(s):  
Barbara Strug ◽  
Anna Paszynśka ◽  
Maciej Paszynśki ◽  
Ewa Grabska
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Graph Grammar ◽  
Graph Grammars ◽  
The Finite Element Method ◽  
Computational Mesh ◽  
Composite Graph ◽  
Initial Mesh ◽  
Grammar Rules ◽  
Element Method

Abstract The paper presents a system of Composite Graph Grammars (CGGs)modelling adaptive two dimensional hp Finite Element Method (hp-FEM) algorithms with rectangular finite elements. A computational mesh is represented by a composite graph. The operations performed over the mesh are defined by the graph grammar rules. The CGG system contains different graph grammars defining different kinds of rules of mesh transformations. These grammars allow one to generate the initial mesh, assign values to element nodes and perform h- and p-adaptations. The CGG system is illustrated with an example from the domain of geophysics.

Framework for Generating Modularized Product Designs With Assembly and Variety Considerations

2008 ◽  
Author(s):  
Saraj Gupta ◽  
Gu¨l E. Okudan
Keyword(s):  
Conceptual Design ◽  
Personal Experience ◽  
Graph Grammar ◽  
Design Stage ◽  
Design For Assembly ◽  
Computational Tools ◽  
Design Alternatives ◽  
Grammar Rules ◽  
Design For Variety ◽  
Two Alternatives

Conceptual design is found to be the most ambiguous and creative phase of design. There exist only a few computational tools that aid designers at conceptual design stage, and mostly designers rely on personal experience or experience of coworkers to generate quality designs. The proposed framework aims at generating robust computerized conceptual designs by incorporating Modularity, Design for Assembly (DFA) and Design for Variety (DFV) principles at the conceptual stage. Conceptual design alternatives obtained from the proposed framework are ranked based on minimum assembly time, and are composed of modules in a way that future changes in customer needs are satisfied only by replacing certain modules. The framework involves searching a design repository of components by using functional-basis and pre-defined graph grammar rules, to generate all possible conceptual design alternatives. These design alternatives are ranked and filtered using a DFA index, and top two alternatives are selected. Selected designs are modularized and filtered using a DFV index to obtain the best design alternative. This paper provides a detailed discussion of the framework obtained by amalgamating Modularity, DFA, and DFV. Working of the proposed framework is demonstrated with the help of an electronic toothbrush design example.

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