An Analysis and Optimization of Double Parallelogram Lifting Mechanism
Double Parallelogram Lifting Mechanism (DPLM) is a compact and stable lifting mechanism with a large extension range widely adopted in robot designs. Rubber bands and springs are often installed on the DPLM to lighten the motors' load and maintain its height, yet the installation positions are often obtained through trial and error. This project aims at finding the optimal rubber band installation positions for DPLM using modeling and optimization techniques. A mathematical model which describes the forces and moments acting on all the linkages of DPLM was derived based on the conditions for the static equilibrium and verified with a 3D simulation software. A genetic algorithm (GA) was implemented to optimize rubber band installation positions, which managed to find solutions with the overall root-mean-square- error (RMSE) of the net moment less than 2 for 2 to 6 rubber bands. A further statistical analysis of 50000 random rubber band samples showed that installing rubber bands in triangles is the best solution with the overall lowest RMSE. A test was conducted with a prototype of the DPLM and the results were consistent with our model and optimization. This project derived and verified a mathematical model for the DPLM, and found the optimal way and positions to install rubber bands. The results of this project provides a theoretical basis for controlling DPLM with rubber bands, allowing it to be further adopted in industrial robots that require repetitive lifting and lowering such as inspection robots and aerial work platforms.
Using P.I.P. to strengthen roads: Plastic incinerated by plastic
People have become accustomed to single-use plastics. These are plastics that are used once only and are then thrown away or recycled. A piece of plastic can only be recycled 2-3 times before it is of bad quality and can no longer be of use. (Achyut K. Panda, 2019). Plastic waste fills up landfills and oceans, becoming hazardous and harmful to wildlife, while emitting greenhouse gasses. Alternatives, such as metal straws and paper bags have turned out inefficient and plastic is still a great need in society. Another way of getting rid of waste plastic is to burn it. Fossil fuels such as coal and natural gas are being utilised to burn plastic in industry. This causes many harmful emissions, such as carbon dioxide and carbon monoxide released from burning the plastic. It results in more damage being done than just leaving the plastic in a landfill. These emissions can be cleaned before being released into the atmosphere. Plastic is made of petroleum, so when it is burned it is converted back into a fuel. Plastic can be burned under controlled conditions to create a fuel source that can be used, thereby utilising the waste plastic. The research conducted aims to investigate the use of plastic waste to burn other plastic to create a renewable fuel source and to eliminate plastic waste.