Design of compliant mechanisms using continuum topology optimization: A review

The design and control of a novel piezoelectric actuated compliant microgripper is studied in this paper to achieve fast, precise, and robust micro grasping operations. First, the microgripper mechanism was designed to get a large jaw motion stroke. A three-stage flexure-based amplification composed of the homothetic bridge and leverage mechanisms was developed and the key structure parameters were optimized. The microgripper was manufactured using the wire electro discharge machining technique. Finite element analysis and experimental tests were carried out to examine the performance of the microgripper mechanism. The results show that the developed microgripper has a large amplification factor of 22.6. Dynamic modeling was conducted using experimental system identification, and the displacement and force transfer functions were obtained. The position/force switching control strategy was utilized to realize both precision position tracking and force regulation. The controller composed of an incremental proportional-integral-derivative control and a discrete sliding mode control with exponential reaching law was designed based on the dynamic models. Experiments were performed to investigate the control performance during micro grasping process, and the results show that the developed compliant microgripper exhibits good performance, and fast and robust grasping operations can be realized using the developed microgripper and controller.

Design and Control of a Compliant Microgripper With a Large Amplification Ratio for High-Speed Micro Manipulation

A Comprehensive Survey on Microgrippers Design: Mechanical Structure

A Comprehensive Survey on Microgrippers Design: Operational Strategy

Aluminium and aluminium alloys

Precision engineering industries demand devices with high-precision motion, the manipulation of micro-objects in particular, which is a highly challenging task. The microgripper is an essential device during the micromanipulation of objects. Precision manipulations of objects entirely depend on the design of the microgripper and are complicated to achieve using the conventional rigid link mechanism. The compliant mechanism is found to overcome the complexities of the rigid link mechanism in precision applications. The micro-object may slip or slide during gripping and releasing, which can be controlled through parallel movement of the gripping jaws. This research article focuses on the design of a compliant microgripper with parallel moving jaws by employing the Hoekens straight line mechanism. The Hoekens mechanism consists of binary and ternary revolute joints, which demand a special type of flexure hinges. Hence, the article introduces the cartwheel type of flexure hinges, as cartwheel-type flexure hinges are more suitable to achieve rotational deformation, values approximating nearly to that of the traditional revolute joint when it transfers motion between fixed and moving links. The outer rim of the cartwheel is modified to allow ternary and binary joints between moving links. Cartwheel is designed with curved flexure arms that are limited to eight numbers of flexures. The structural behavior of the cartwheel is analyzed by varying numbered flexures from 1 to 8. The minimum number of flexure arms required for having better rotational performance is determined through Finite Element Analysis (FEA). An appropriate type of cartwheel is positioned in the mechanism. The structural performance of the designed microgripper is carried out through FEA, and its parallel movement is verified. The microgripper is fabricated from structural steel through wire Electrical Discharge Machining (EDM) technique and actuated using Shape Memory Alloy wire. The displacement of the microgripper jaw is experimentally measured, and the results show a promising improvement.

Design of Compliant Mechanism Microgripper Utilizing the Hoekens Straight Line Mechanism

A compliant mechanism-based micro/nanopositioning stages are used to perform high precision motion in various fields. In recent years, researches proposed various methods to achieve the compliant m...

Design and testing of a compliant mechanism-based XYθ stage for micro/nanopositioning

The density level of the part produced by the Powder Metallurgy route is purely controlled by the parameter such as the amount of pressure applied; ram velocity, friction between the powder and the die surfaces. In this research work, an attempt has been made to investigate experimentally the powder compaction of Al-10%Cu metal matrix composites and numerical method was used to simulate the compressibility study of the above mentioned PM process. The experimental and numerical results revealed that the effect of the second phase particle in the void ratio development and the level of enhancement in the relative density of PM compacts. ABAQUS, a finite element tool has been used for performing the numerical simulation utilizing the CAM—CLAY and Porous Metal Plasticity models for the prediction of void ratio and relative density enhancements of the material considered.

Experimental Studies and Numerical Simulation of Compressibility of Al—10% Cu Powder Metallurgy Composites

In recent development in engineering, researchers and scientists are more interested in precision manufacturing, assembly and manipulation of small parts. For manipulation and assembly of small parts, microgripper is the key component to handle microsized objects with precision at the micron level. The design of microgripper is required to consider many aspects of microphysics. Microgripper is functionally divided into two divisions such as mechanism part and gripping jaw segment. This research paper mainly focuses on devising the mechanism segment of a microgripper which basically transfers the motion in precise and controlled manner and is generally complicated to design. Topology optimization is utilized to design a compliant mechanism for a microgripper since it is the best choice for microlevel actuators. Topological optimized design is required for performing post-processing and removing the staircase effect and node-to-node connectivity developed during design. Various filtering and interpolation methods are adopted to minimize the limitations of topology optimization and also to generate mesh independence and perfect boundary. Finite element method (FEM) is used to analyze the microgripper developed through topology optimization technique, and the results are compared with a rigid body model which is equivalent of the mechanism. Graphical position analysis is also carried out to find the output displacement of an equivalent rigid body model of microgripper mechanism.

Introducing Various Image Processing Techniques to Improve Topology Optimization Process to Develop Compliant Mechanism-Based Microgripper

The present analysis gives an insight to understand the preparation of composite materials using biodegradable wastes. In the current scenario, disposal of non-degradable materials like electronic waste, construction waste, biomedical waste, radioactive waste and industrial waste are main problems to the human society. In the organic waste, the major portion of waste is fallen from trees as dry leaves. Those leaf wastes are not handled appropriately and due to human ignorance, they are not disposed properly. The pollutants that are generated from the burning leaves enter into the atmosphere which results in greenhouse gas effect as a whole, as well as the formation of particulate matter. The composite can be easily manufactured from the dry leaves at desired shape through casting process by using the raw sources available from the plant waste. The composite developed without any additives, chemical treatments and synthetic fillers was a biodegradable and eco-friendly material.

R. Bharanidaran

Papers

Design of Compliant Mechanism Microgripper Utilizing the Hoekens Straight Line Mechanism

Design and testing of a compliant mechanism-based XYθ stage for micro/nanopositioning

Experimental Studies and Numerical Simulation of Compressibility of Al—10% Cu Powder Metallurgy Composites

Introducing Various Image Processing Techniques to Improve Topology Optimization Process to Develop Compliant Mechanism-Based Microgripper

Biodegradable Composites from Leaf Wastes for Packing Applications