Robot end-effectors - grasping the new challenges (and opportunities)

Citation

Caldwell, D. (2003), "Robot end-effectors - grasping the new challenges (and opportunities)", Industrial Robot, Vol. 30 No. 4. https://doi.org/10.1108/ir.2003.04930daa.002

Robot end-effectors - grasping the new challenges (and opportunities)

Robot end-effectors – grasping the new challenges (and opportunities)

Darwin Caldwellis based at the Department of Electronic Engineering, University of Salford, Manchester, UK

Keywords: End-effectors, Grippers

Robotic manipulator arms have more power, accuracy, flexibility, range of motion and speed than the human arm and they have, quite rightly, gained a reputation as the most flexible and dextrous of automation systems. Given this high performance capacity, we might seriously consider why there is still a relatively slow uptake of robots, and why the number of industries that have embraced the technology is still comparatively small.

There are, of course, many reasons for this: social, economic, educational, and ultimately technological. Within the technology demands, there are again many limitations, but it is apparent that one of the major constraints is the limited performance of the end-effector and its ability (or more accurately its inability) to manipulate a wide range of products easily and effectively.

Clearly although robot arms form a sophisticated general purpose manipulation tool, the end-effector, which is after all the critical interface between the robot and the external environment, remains a clumsy device possessing few articulations and generally lacking any sense of touch.

For many traditional applications, the limitations of the end-effector have been well known and the methods of dealing with this interface failing have been developed. In these domains, the limitations do not prove to be too much of an operational or economic drawback because the relatively crude “hand” is usually adequate for all the tasks to be performed. Indeed, in many operations, the use of a more simplest interface to the world has meant that the task can be broken down into more manageable roles. This can ultimately make the work process more efficient and reliable. At the same time, the robust mechanical construction found in most current end-effectors means that they can be designed to withstand environmental extremes such as: heat, pressure, chemical and radiation exposure and masses that would simply be too severe for more complex grippers or humans.

The goal of all those involved with robots is to see the applications and capacities developed and this means finding new operating tasks and environments. Several growth areas have been suggested in the past 5 years: construction, medicine, agriculture, etc. and there have been some notable successes in each of these areas, but often there is a feeling that the robot hand does not, will not, and possibly cannot, have the capacity of the human operators hand and therefore, the robot can never have the flexibility of a human worker, hence preventing their wide scale adoption.

The whole food sector, from farm production to the consumer through processing/assembly, is one such area. This is the largest industrial sector in Europe and economic and legislative requirements have combined to encourage companies to consider new “high-tech” options that would have been unheard of 10 years back. But many within these industries have low expectation of the capacity of robots to handle products that are organic, and therefore highly variable (texture, colour, shape and size). There is also a feeling that an engineering understanding of the product cannot be achieved, and this combined with a lack of handling strategies for compliant, deformable and easily damaged materials, and end-effectors designed to cope with these variable characteristics, means that although robotic innovation would be desirable, it is often not believed to be feasible.

The opportunity to develop new robotic solutions for the food and other sectors is now upon us, but to do this, we need to have an open and creative approach to the new demands of the product and the industries. At the same time, we need to persuade those within the industries that new approaches to the task developed through the use of robotic and automated handling techniques are viable, even when they offer solutions very different from the current modes of production.

This issue of Industrial Robot will show that there are new techniques for handling both the conventional and the new product lines and suggests that even those problem that we might have considered intractable only a few years back are now possible.