Robots use many different Mechanical grippers to manipulate objects.

PawBot grippers are designed to be Encompassing Grippers which reduces the mechanican load on the gripper motors once a pet food can has been encompassed within gripper cavity. In comparison, if food can was held using pressure, it would create a continous pressure on the gripper motor which would reduce the life of this motor.

Other complex grippers with more sophisticated programming can be used to do more complex tasks. Loading dishwasher for example. But such robot will be more expensive as expected and might not be available readily on the market.