Smooth robot movements reduce energy consumption by up to 40%
24 August 2015
By minimising the acceleration of industrial robots, energy consumption can be reduced by up to 40 percent – while retaining the given production time.
This is the result of a new optimisation algorithm that was developed by researchers at Chalmers University of Technology. Optimisation of the robot's movements reduces acceleration and deceleration, as well as the time the robot is at a standstill, since being at a standstill also consumes energy.
“We simply let the robot move slower instead of waiting for other robots and machines to catch up before carrying out the next sequence," says Professor Bengt Lennartson who initiated the research together with, among others, General Motors. "The optimisation also determines the order in which the various operations are carried out to minimize energy consumption – without reducing the total execution time.”
The optimisation never changes the robot’s operation path, only the speed and sequence. “Thus, we can go into an existing robot cell and perform a quick optimisation without impacting production or the current cycle,” says Professor Lennartson.
To achieve safe optimisation, several robots moving in the same area need to be coordinated. The optimisation tool will therefore initially identify where robots may collide, and the entry and exit positions for each collision zone, and for each robot path.
“The first test results have shown a significant improvement, such as a 15 to 40 percent energy reduction, but the results are still preliminary," says Kristofer Bengtsson, who is responsible for the implementation of the new optimisation strategy. "In order to estimate the actual energy savings, further testing in industry is required.”
In robot-intensive manufacturing industries, such as bodywork factories in the automotive industry, robots consume about half of the total energy used for production.
The optimisation program starts by logging the movements of each robot during an operations cycle, as well as any collision zones. This information is processed by the optimiser, which generates new control instructions that can be directly executed by the robots.
“The goal is to make this kind of optimisation standard, and included in robots from the start," says Dr Bengtsson. "At each adjustment of the operating sequences, a new optimization is conducted by default. But as we all know, it takes time to bring a development product into a robust production process, with several years of engineering work.”