Page 38 - European Energy Innovation - Spring 2016 publication
P. 38

38  Spring 2016 European Energy Innovation


Smooth robot movements reduce
energy consumption by up to 30 percent

By Prof Bengt Lennartson and Dr Kristofer Bengtsson, Chalmers University of Technology, Gothenburg, Sweden

By minimizing the acceleration
              of industrial robots, energy
              consumption can be reduced
              by up to 30 percent – while
 retaining the given production time.
 This is the result of a new optimization
 algorithm that has been developed by
 researchers at Chalmers University of
 Technology. The research was initiated
 by General Motors, and is now further
 developed in the EU project AREUS,
 together with, among others, Daimler
 and KUKA.

MOVE SLOWER INSTEAD OF                    show that it is possible to save up to   EXPLOITATION AND IMPACT
WAITING                                   30% energy and 50% peak power,           The goal is to make this kind of
Optimization of the robot's               neither substituting any hardware nor    optimization standard, and included in
movements reduces acceleration and        provoking negative consequences on       robots from the start. However, since
deceleration, as well as the time the     the overall plant production. The fact   the optimization procedure is based
robot is at a standstill, since being at  that the solution still keeps a desired  on the original robot behaviour and
a standstill also consumes energy. A      production time is crucial to get        does not change the robot’s operation
basic idea is here to let a robot move    industrial acceptance. Furthermore,      path, it can also be applied to existing
slower instead of waiting for other       the solution does not depend on          robot cells. A quick optimization can
robots and machines to catch up,          any physical model parameters, but       then be performed without changing
before carrying out the next operation    only a simple recording of the robot     the current production conditions, just
sequence. The optimization also           path generated by the original robot     reducing the energy consumption.
determines the order in which the         program. This makes the proposed         The optimization concept is also not
various operations are carried out, to    method very attractive from a user       limited to robot motions, but can be
minimize energy consumption without       perspective.                             applied to, e.g., automated guided
reducing the total execution time.                                                 vehicles (AGVs), conveyor systems, and
                                          COLLISION AVOIDANCE                      press lines.
REDUCED ENERGY AND PEAK                   The optimization tool is included in
POWER                                     a software developed at Chalmers,        Finally, we observe that in robot-
Evaluations on industrial robots          called Sequence Planner. To achieve      intensive manufacturing industries,
                                          a safe optimization, several robots      such as bodywork factories in the
                                          moving in the same area need to          automotive industry, robots consume
                                          be coordinated. Collision zones          about half of the total energy used
                                          where robots may collide can             for production. This means that the
                                          then be automatically generated          proposed energy and peak power
                                          by CAD software for robots. The          optimization could lead to potentially
                                          intersections between sweep volumes      significant savings, especially in
                                          of the individual robot motions then     automotive industry. l
                                          determine these collision zones, and
                                          a robot needs to book such zones to        Contact details:
                                          be allowed to path corresponding
                                          region. This collision avoidance           Dr Kristofer Bengtsson
                                          procedure is integrated in the energy
                                          optimization. Thus, we obtain both
                                          a collision free and energy optimal        Prof. Bengt Lennartson
                                          robot system that keeps the desired
                                          production time.

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