A patient lift is used mostly in the hospitals and its main aim is to help nurses to carry patients from one place to another. Today these patient lifts are equipped with motors that can lift patient to some height and then pull down. But the weight of patient lift with hanging person is rather big and it is not easy to push it. In order to help nurses to move the patient lift, the wheels can be driven by motors. These motors can be controlled by the nurse with help of a joystick, but wrong movement of nurse’s hand can cause collision with a bed or a wall. To avoid collision and make the process of moving the patient lift more robust and natural it is better to combine the human power, which is produced by pushing the patient lift, with the electrical motors on the wheels, which give additional power assistance. The motor-driven patient lift studied here is controlled by velocity feedback. The objective of this thesis is to develop software for the hardware and build a control law, which will help to move the patient lift and will be stable. The thesis consists of two main parts. The first part includes all experimental setup and developing the software. In this part the drivers for motors and encoders have been written, the input step excitation has been implemented and all preparations for experiments have been done. The second part includes modelling and control design. In the modelling part all the experiments were carried out, the models were chosen and the parameters for these models were calculated. Two models have been made because of changed behaviour of the patient lift with and without additional weight. In the control design part the RST controller (R,S,T are characteristic polynomials of the controller) was chosen, implemented, downloaded into the control board, the parameters for this controller were calculated and then th...
