Achieving High Speed and Accuracy While Preserving Design Flexibility with Vibration Reduction Technology
One of the challenges in robot control is vibration. Vibration increases in proportion to the operating speed of the robot and can adversely affect the support base and surrounding equipment. Meanwhile, manufacturers need to accelerate the speed at which robots move to shorten the time required for each process on the manufacturing line.
Epson developed Vibration Reduction Technology (VRT) to maximize the utility of its own robots. VRT reduces vibrations in the support base, end-effector, cameras, and other components by controlling how the robot moves. It also minimizes vibration caused by robot movement and enables low-cost, flexible system design.
Challenges for speeding up robots
Manufacturers want to increase productivity by reducing the time required for each process without sacrificing product quality. This requires moving the robot at high speed and with high acceleration. However, the faster the robot moves, the greater the vibration it generates and the more residual vibration there is after the robot stops. Not only does the robot itself vibrate but also the support base to which the robot is secured, and any sensors, cameras, and other devices installed on the robot.
Even if there is little residual vibration in the robot itself, a large amount of residual vibration in the support base would make it difficult to operate the robot at high speed and with good positioning accuracy. However, if the robot must wait until the residual vibration subsides to preserve accuracy, the time required for each process will increase. Sensor and camera vibration would also increase the possibility of errors in detected data, leading to poor product quality.
Manufacturers need technology that maximizes the performance of the entire manufacturing system by reducing vibration in robots and peripheral equipment while maintaining high speeds.
Methods of reducing vibration and related issues
The methods below are commonly used to reduce robot vibration and increase robot accuracy.
- Move the robot at low speed and low acceleration.
- Increase the rigidity of the robot arm and reduce the weight of payloads.
- Increase the rigidity of the support base and bolt the robot tightly to it.
- Use cushioning material to prevent vibration from being transmitted to the surrounding
Slowing down the robot's movements will generate less vibration but make it impossible to shorten cycle times. Increasing the rigidity of the robot arm and support base is
problematic because it's costly and limits locations where robots can be installed.
When a robot is suspended from a frame, vibration is usually reduced to an acceptable level by using a highly rigid, welded iron support base. However, welded support bases
with iron frames take time and money to make and their height is not adjustable, so they cannot easily be repurposed. An aluminum support base with an aluminum frame is easy to
make, but aluminum lacks rigidity and the mounts are weak, so it takes time for the residual vibration to settle during robot operation. The last method, using cushioning
material, is a less than ideal option in terms of space efficiency.
Advantages of introducing VRT
VRT reduces vibrations of the support base, end-effector, cameras, and other components by controlling how the robot moves according to the characteristics of these components. This technology is especially effective when a robot with large vibration is suspended from a frame. In some cases, it has reduced vibration by about 90%.
Advantages of VRT
VRT, which saves space and enables high speed and accuracy, maximizes the performance of Epson robots and contributes to production line productivity.
