Abstract to EUCASS 2013

One of the main reasons for the development of space manipulators is to replace astronauts to perform tasks that involving long, repetitive operations and unhealthy, hazardous environment. Due to the particular harsh environment of space and the increasing demands of satellite maintenance, on-orbit refueling and assembly etc., the application of space robot has received significant attention. Some research has been done in the area of satellite capturing task, such as “Robot Technology Experiment (ROTEX)”, “Engineering Test Satellite VII (ETS-VII)” project, and “Orbital Express (OE)” program etc. Conventional linear controllers (PID) are not really suitable for the control of space manipulators due to the highly nonlinear behavior of the space robot model. Model predictive control (MPC) has been used in the chemical process control industry with great success; however, the application of predictive control in the aerospace industry appears relatively new. Popularity of the model predictive control approach lies in its relatively simple idea as well as in its practical advantages. In principle, MPC is a feedback control scheme, for which in each sampling period, a finite horizon optimization problem is solved. An illustration of MPC schematic diagram is shown in Figure 1. One of the main benefits of predictive control is that the constraints on the inputs and outputs of the system can be explicitly considered in the control problem formulation.