Beyond our grasp?

Citation

Loughlin, C. (2003), "Beyond our grasp?", Industrial Robot, Vol. 30 No. 4. https://doi.org/10.1108/ir.2003.04930daa.001

Beyond our grasp?

Beyond our grasp?

Two questions I often get asked are "what is happening in robotics?" and "where is it going?"

The simple ones are always the hardest to answer.

Robot arms are pretty useless by themselves and yet it is the arms that have received the lion's is share of development funding. The result are arms that are so reliable that further improvements will provide only marginal benefit, and so fast that if they went any faster they would probably damage the items or tools that they carry. There is still scope for further developments, but it must be becoming harder and harder for the engineers to justify the RD expenditure.

However, despite the above impressive achievements, robot arms are still pretty useless by themselves. The only thing that actually allows the robot to do something useful is its end-effector. This can be a gripper that allows it to pick up and place components, or a tool such as a welding torch or deburrer.

In this issue, we are taking a look at some of the latest developments in gripper and end-effector technology and in particular, at flexible grippers that can accommodate a wide variety of components.

If the number of different parts that you need to handle is small, or if they have very similar shapes, then the present generation of end-effectors will probably be sufficient. And in the best spirit of "keep it simple" they are likely to be the best solution as well. However, if you have more than a very limited number of parts, or if those parts can be presented in a variety of orientations, then you need something considerably more flexible.

A flexible gripper is also highly technically challenging because not only does it tend to have more degrees of freedom than the robot arm, but also it needs to cram them into a very small space, be lightweight and also strong enough for the job in hand. No wonder that the major robot manufacturers have studiously avoided putting much effort into this area.

Also it is one thing picking up something, but quite another to also be able to put it down again. If it is sticky or so small that electrostatic forces come into play, then you will have to actively let it go rather than passively let gravity take its course.

Service robots will definitely need flexible end-effectors to handle the variety of tasks that we hope to throw at them. Industrial robots will almost certainly need them as well, if we are to use them within flexible or reprogrammable assembly cells, and as components become ever smaller, we will find that existing gripper catalogues gather dust on our bookshelves.

Until quite recently, the choice for production engineers was "should we use a person or a robot?". These days, and increasingly for the future, people will not be able to perform the required tasks. Unless more attention is given to end-effector development, robots will not be able to do them either.

Clive Loughlin