The current range of industrial robots is not capable of comprehending human behavior. These robots can also not react to human intentions. Robots in the future will be developed to ensure safety for humans.
Most industrial robots operate in confined surroundings as they can easily cause damage to human beings. The safety factor proves why passive devices are used to interact with humans on an automotive assembly line.
Passive devices are unable to supply power and hence lower the risk of injury to humans. They are reliable, safe, and provide assistance for workers. They can lessen the effort level of an employee required to transport an object by counterbalancing a static load. Static loads can be counterbalanced using a pneumatic actuator. Knight Global is a pioneer in the production of static devices such as torque tubes, suspended cables, and passive arms.
Passive devices have a few disadvantages as they can truncate only static forces. These devices are ideal for lifting small to medium payloads. They cannot be used to lift loads of enormous weights, where inertia and friction forces become more prominent.
Source: http://www.robotiq.com