Abstract
The healthcare centers at rural areas will have a lack of available sonographers who can perform ultrasound examinations on patients. To solve this issue and allow the patient to receive the necessary help, it is beneficial for the healthcare centers to take into use a tele-echography system. A tele-echography system is a system based on bilateral tele-operation, meaning that the ultrasound examination is performed remotely and using force-feedback the sonographer can receive the sensation of controlling the patient’s environment directly. To allow such system to operate, a communication network is used as the medium that holds the system together and allows for communication to happen between the two locations. However, when using a communication network, there will be an occurrence of time-delay during the exchange of data between the locations. Time-delay will cause issues such as lengthy procedure time and inaccurate performance. Additionally, it has from previously done work been proven that delayed bilateral systems will cause instability in the system. This thesis aims to solve these issues by designing a control architecture that will allow ultrasound examinations to be performed without time-delay being a hindrance. To limit the effects of time-delay, there exists specific control strategies that can be taken into use. One of them being the wave variable method, which transforms the power variables in the system (velocity and force) into wave variables before transmitted through the communication channel. The method is known to allow bilateral systems to maintain their stability when dealing with time-delay, but its use does not produce good tracking performance. To compensate, there can be done modifications to the method that will allow the system to produce accurate tracking performances while maintaining its stability during remote use. To test the designed controller there was created a simplified 1-DoF Simulink model based on the controller’s architecture. The model was tested with time-delay values of 200, 400, and 600 ms. The results of the simulations were found to be sufficient and give a good indication that the designed controller will allow real-world systems to produce desirable results.