Multi-Tooth Contact Analysis and Tooth Profile Modification Optimization for Cycloid Drives in Industrial Robots

Cycloid drives are widely used in industrial robots where high load carrying capacity, accurate positioning precision and smooth motion are required strictly. The meshing clearance obtained by tooth profile modifications of cycloid gears is thought to have significant effects on performances of cycloid drives. In this study, this issue is clarified by developing a quasi-static load distribution model with considering four types of tooth profile modifications. Firstly, the unloaded tooth contact analysis is introduced to determine the meshing information, and the nonlinear Hertzian contact mechanics is applied to develop force-displacement relationships, Then, the loads distributed on gears, contact stress, loaded transmission error and gear ratio are calculated by enforcing the deformation compatibility, and force and moment equilibrium conditions. The predicted contact stress and deformation are compared with those by the finite element method, which shows a good agreement. With this, a tooth profile modification optimization method is proposed to obtain the optimal tooth profile modification at given radial clearances by using the two-dimensional parameter map. This study provides a useful tool to predict the multi-tooth contact conditions and to determine the most suitable tooth profile modification during the design process

Modelling and Design of a Test Rig to investigate the dynamic behaviour of a Servo driven Powertrain

In the present work a simulation model for examining the fundamental dynamic behaviour of a servo driven powertrain is developed. This powertrain consists of a permanent magnet synchronous motor, a cycloidal gearbox and a torque motor to apply a load. On basis of this model the selection of components for the design of a test rig is possible. This leads to the constructive draft of the test rig. In order to model the system, the fundamentals give a brief overview of the components incorporated in the test rig system. With ais of the specified task the simulation purpose is defined and the modelling process enabled. The subsequent system analysis is performed intensively to decompose the system into subsystems, which are then investigated to find the optimal modelling approach for the given simulation task. Particular emphasis is put on the investigation of the cycloidal gearbox subsystem and it shows, that approaches for modelling the dynamic behaviour of the gearbox as a whole have only been published partially. Therefore, the available modelling approaches are analysed and suitable models are developed as conceptual models. Those will be formalised and implemented in Matlab/Simulink. The model is verified and simulation experiments are performed, that help in the selection of suitable test rig components. On basis of a flexible test rig, finally the constructive draft is presented.:1 Introduction 1.1 Motivation 1.2 Procedure 2 Fundamentals 2.1 Definitions 2.2 Modelling 2.3 Servo Drive 2.3.1 Introduction 2.3.2 Permanent Magnet Synchronous Motor 2.3.3 Servo Inverter 2.3.4 Control System 2.4 Torque Motor 2.5 Gearbox 3 Specified Task 4 System Analysis 4.1 Introduction 4.2 Servo Inverter 4.3 Control System 4.4 Servo Motor 4.5 Transmission Elements 4.6 Cycloidal Gearbox 5 Model Formalisation 5.1 Introduction 5.2 Servo Inverter 5.3 Control System 5.4 Servo Motor 5.5 Transmission Elements 5.6 Cycloidal Gearbox 6 Model Implementation 6.1 Introduction 6.2 Servo Inverter 6.3 Control System 6.4 Servo Motor 6.5 Transmission Elements 6.6 Cycloidal Gearbox 7 Simulation 7.1 Introduction 7.2 Solver 7.3 Verification 7.4 System Evaluation 7.4.1 Sensitivity Analysis 7.4.2 Stability Analysis 8 Design of the Test Rig 8.1 Selection of the components 8.2 Constructive Draft 9 Summary and Outloo