Calculations for a 3-stage single-speed reduction gearbox

Hello everyone, my group and I are working on a project for a gearbox design for a servomotor as a part of the challenge 'LF ConnectNext Program India 2021-22'. The project is titled 'Design and development of Modular Gearbox', but we are facing some problems regarding the calculations of the gearbox design. We need some reference material for the design calculations of a single-speed multi-stage reduction gearbox. We found some reference calculations during the literature survey, but they were for multi-speed gearboxes or single-stage gearboxes. So if you have some reference material or even calculations please do help us. Also the specific input parameters for the design are also attached below.

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