A waste sorting robot can include a manipulator comprising a suction gripper for interacting with one or more waste objects to be sorted within a working area, and wherein the manipulator is moveable within the working area. There is a controller configured to send control instructions to the manipulator. At least one pressure sensor is in fluid communication with the suction gripper and configured to generate a pressure signal in dependence on a fluid pressure in the suction gripper. The controller is configured to receive the pressure signal and to determine manipulator instructions in dependence on the pressure signal.