A mixed integer predictive controller with multi-constraint for free-floating space robots

For the obstacle avoidance problem of space robots, a mixed integer predictive controller is developed for the free-floating space robots. Firstly, in the frame of model predictive control method, the joint physical limits and obstacle avoidance requirement are described as inequality constraints of the optimal control problem, and the controller with linear quadratic programming form can be obtained. Secondly, priorities of the constraints in the controller are established based on the propositional logic theory to guarantee the optimal solution to be derived under the satisfaction of the maximum number of constraints, which effectively makes up for the deficiency issue that multiple constraints may lead to the optimal control problem infeasible when model predictive control method is used to control space robots. Finally, numerical simulations are conducted to prove the effectiveness of the proposed control strategy.