Simulation of Electromechanically Actuated Boom
Väisänen, Topias (2023)
Väisänen, Topias
2023
Konetekniikan DI-ohjelma - Master's Programme in Mechanical Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2023-03-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202301271818
https://urn.fi/URN:NBN:fi:tuni-202301271818
Tiivistelmä
Environmental consciousness has made electrification of mobile machines a popular trend in recent years. Electromechanical linear actuators (EMLAs) may be used to replace hydraulic cylinders in mobile machines. In this thesis a simulation model for a boom with single EMLA is developed. The EMLA consists of a permanent magnet synchronous motor (PMSM), gearbox and ball screw. The objective of this thesis is to develop a simulation model that includes the EMLA, the control system and the mechanical model of the boom. The simulations are carried out in Matlab Simulink environment. The simulation model is validated by comparing simulation results with measurement data of the actual system.
Structure, operating principle, mathematical equations and common control structure of PMSM are introduced to develop a simulation model for the motor and motor controller. The motor used in this thesis uses Hall sensors as feedback device. The downsides and challenges of using such low-resolution sensors are also covered in this thesis. A spring-mass model is used to model the mechanics of the actuator. The equations to obtain parameters for the spring mass models are introduced. Friction of the actuator is also studied, and it is found out that there are no friction models that could predict the friction accurately using basic parameters of the ball-screw. There are many components corresponding to total friction and developing an experimental model is the best option. A simple assumption of constant efficiency of the actuator is used in this thesis.
The simulation model of the motor and motor controller was validated independently of the rest of the system by utilizing a motor test bench. It was found out that the models are sufficiently accurate to be used for complete system modelling, including the EMLA and the boom. The complete model was then developed, and the results were compared with measurement data from the real system. The results showed similarities and the simulator managed to show controllability issues of the real system. The issues were caused by slow control loop frequency and delay in the control loop. To improve the systems performance a motor and a motor controller better suited for motion control applications should be used. It was found out that the simple friction model used is not accurate and a better model should be developed.
Structure, operating principle, mathematical equations and common control structure of PMSM are introduced to develop a simulation model for the motor and motor controller. The motor used in this thesis uses Hall sensors as feedback device. The downsides and challenges of using such low-resolution sensors are also covered in this thesis. A spring-mass model is used to model the mechanics of the actuator. The equations to obtain parameters for the spring mass models are introduced. Friction of the actuator is also studied, and it is found out that there are no friction models that could predict the friction accurately using basic parameters of the ball-screw. There are many components corresponding to total friction and developing an experimental model is the best option. A simple assumption of constant efficiency of the actuator is used in this thesis.
The simulation model of the motor and motor controller was validated independently of the rest of the system by utilizing a motor test bench. It was found out that the models are sufficiently accurate to be used for complete system modelling, including the EMLA and the boom. The complete model was then developed, and the results were compared with measurement data from the real system. The results showed similarities and the simulator managed to show controllability issues of the real system. The issues were caused by slow control loop frequency and delay in the control loop. To improve the systems performance a motor and a motor controller better suited for motion control applications should be used. It was found out that the simple friction model used is not accurate and a better model should be developed.