Model-based approach for load orientation with redundantly actuated parallel platform
Haltia, Anssi (2023)
2023
Konetekniikan DI-ohjelma - Master's Programme in Mechanical Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. Only for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2023-05-23
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202305035043
https://urn.fi/URN:NBN:fi:tuni-202305035043
Tiivistelmä
This thesis is an initial control system design and performance study for a load orientation task with a redundantly actuated parallel platform in a mobile machine environment. Due to the redundant actuation, the cylinder motions are coupled together and need to be synchronized. This combined with mobile hydraulics creates a challenging task for a motion control application. Mechanical and hydraulic design and the industrial environment require that the system can perform with the selected components and under parameter uncertainties caused by production tolerances and setting values.
Model-based design tools are utilized to build and validate a simulation model for early-stage testing of the developed control algorithm. Using a model-based approach the testing of the initial algorithm is much more efficient, cheaper, and safe. The simulation model of the physical system is constructed by using MathWorks Simulink and Simscape components. The control algorithm is based on an inverse kinematic solution and closed-loop cylinder position control with velocity feed-forward.
Testing of the developed control system is done with a few selected test inputs. First with nominal hydraulic parameters and then with couple uncertainties. The selected uncertainties are valve current offsets representing a bad calibration result and different precharge pressures in hydraulic accumulators presenting changes in the design parameters or a breakdown.
The developed control algorithm with nominal parameters is performing as expected. Further tuning and testing are done by utilizing rapid prototyping with a to-be-constructed physical test bench. Simulation results state that the system pressure levels can easily indicate bad calibration results and that more studies with uncertain parameters should be made to reveal the problematic conditions.
Important future work is to verify the functioning with a real physical prototype with the presence of realistic dynamics and disturbances. Also, the development of an automatic calibration cycle is required for the final implementation.
Model-based design tools are utilized to build and validate a simulation model for early-stage testing of the developed control algorithm. Using a model-based approach the testing of the initial algorithm is much more efficient, cheaper, and safe. The simulation model of the physical system is constructed by using MathWorks Simulink and Simscape components. The control algorithm is based on an inverse kinematic solution and closed-loop cylinder position control with velocity feed-forward.
Testing of the developed control system is done with a few selected test inputs. First with nominal hydraulic parameters and then with couple uncertainties. The selected uncertainties are valve current offsets representing a bad calibration result and different precharge pressures in hydraulic accumulators presenting changes in the design parameters or a breakdown.
The developed control algorithm with nominal parameters is performing as expected. Further tuning and testing are done by utilizing rapid prototyping with a to-be-constructed physical test bench. Simulation results state that the system pressure levels can easily indicate bad calibration results and that more studies with uncertain parameters should be made to reveal the problematic conditions.
Important future work is to verify the functioning with a real physical prototype with the presence of realistic dynamics and disturbances. Also, the development of an automatic calibration cycle is required for the final implementation.