Automating the Perfect Game with E.A.R.L., the Bowling Robot

  • September 27, 2011
  • Case Study
September 2011
ARM Automation develops ultra high precision, EtherCAT-enabled robot for bowling equipment testing
It’s been estimated that more than 70 million people in the United States bowl during the course of a year. Of those, more than 2 million compete regularly in league play certified by the United States Bowling Congress (USBC). Based in Arlington, TX, the USBC is the national governing body for bowling as recognized by the United States Olympic Committee. To help keep millions of American bowlers – from amateur to professional – stocked with the highest performance, top-of-the-line equipment, the USBC has led the charge of bowling research and testing technology for years at the International Bowling Campus. The latest USBC milestone: 2010 marked the age of the higher performance bowling robot. This technological curiosity with a concrete purpose is dubbed E.A.R.L. (Enhanced Automated Robot Launcher) and was developed by the engineering firm, ARM Automation.
The United States Bowling Congress (USBC) has led the charge of bowling research and testing technology for years at the International Bowling Campus.
ARM Automation, a privately held company based in Austin, TX, develops custom automation solutions for challenging industrial applications.  ARM was founded in 1993 with a focus on building modular robotics for hazardous duty applications, but has evolved over the years to serve a variety of industries such as medical, food packaging, consumer product assembly and custom robotics for the entertainment industry and other unique applications. 
Through the years, ARM Automation has developed and built multi-axis orthopedic implant testing systems, modular robots for handling nuclear materials, underwater robotics for some of the world's largest fountain shows, packaging and assembly lines for PC production, mobile robots for warehouse automation, laser micro-machining tools for semiconductor photomask production and more. The common thread through most of these applications is the need for highly custom robotic solutions and the development of new technologies and processes.
“ARM Automation was the only company willing to partner with USBC in order to engineer the exact robotic solution we needed; other robotics integrators simply tried to modify existing products in an attempt to get close to our requirements,” noted Neil Stremmel, Managing Director of the USBC National Governing Body.  “ARM is located within three hours of our office in Arlington making them the perfect choice since their engineers can be on-site with short notice. Before E.A.R.L., ARM Automation had never built a robot for bowling and we’ve never built a robot, so their ability to decipher precisely what we were looking for was imperative to the success of the project.”
The E.A.R.L. robot’s motion system consists of a linear axis to position the ball across the width of the lane, a 5-axis positioning robot, a ball spinner and release mechanism installed on a gripper.
Never a technological gutter ball
With such a diverse robotic resumé, ARM Automation has developed almost every kind of robot solution imaginable. So it should come as no surprise that perhaps the company’s most unique robot project of 2010 was E.A.R.L. the bowling robot. While this robotic kingpin generates a great amount of buzz in the media, E.A.R.L. was developed first and foremost to conduct serious research for the USBC. “E.A.R.L’s abilities will aid us in quantifying the data relating to ball motion and overall scorability, helping us maintain the credibility of our sport,” Stremmel explained. “E.A.R.L has the ability to replicate virtually any bowler’s style, which will aid coaching staff by showing how conditions change as individual bowlers compete and how to properly adjust to the ever-changing bowling environment.”
One of the ways the USBC serves their members is by testing bowling equipment (balls, lane materials, lane oil, etc.) to ensure that it adheres to its published specifications. In order to eliminate the variation that a human bowler would introduce during the tests, the USBC turned to automation and robotics. “The original bowling robot, Harry, didn't offer sufficient repeatability and was cumbersome when adjusting test conditions such as differences in position,” Stephen Grupinski, President, ARM Automation said. “E.A.R.L. was designed as the answer to these limitations. Testing range, position and speed were also dramatically improved by the E.A.R.L. robot.”
 “The biggest challenge overall for the mechanical and electrical controls development was getting the timing of the bowling ball release within 1 ms,” Greg Wiese, Project Engineer, ARM Automation said. “Considering the 24 mph velocity for the ball release that USBC required, if the system dithered 1 ms, it equated to roughly a degree in difference for ball loft and 0.5-in difference relative to the foul line. Any additional dither and the ball could be thrown into the ceiling or slammed into the bowling lane. That’s a major reason why we went with the EtherCAT- and PC-based architecture, which empowered us to handle the external output from the drive with extreme precision and eliminate these potentially dangerous scenarios.”
With what may seem like a simple swing of an arm, there are actually a wide range of parameters that go into a single ball throw test.  A typical E.A.R.L. test setup consists of the following: 1) orientation of the robot gripper relative to the bowling ball's center of gravity, 2) release point of the ball relative to the bowling lane (height, position relative to foul line, position across the width of the lane, loft angle, ball trajectory), and 3) ball release speed and rotation speed. The E.A.R.L. robot’s motion system consists of a linear axis to position the ball across the width of the lane, a 5-axis positioning robot, a ball spinner and release mechanism installed on a gripper.
The E.A.R.L. control system includes a Beckhoff C6920 Industrial PC running TwinCAT NC PTP software and Windows CE operating system, a CP6901 12” Control Panel display, along with EtherCAT as the I/O and drive fieldbus.
Automation that rolls with all the right angles
In order to tackle the tight precision requirements of this unique robot application, ARM Automation selected an EtherCAT- and PC-based control system from Beckhoff Automation. Via a Beckhoff HMI, the USBC personnel can easily input their test setup on E.A.R.L.. There are 11 variables for configuring different throws via the HMI to adjust speed and pick-up orientation. The E.A.R.L. robot with Beckhoff controls can be reconfigured for completely different parameters in less than 10 seconds.
Developed during a six month effort from January to July 2010, the system includes a Beckhoff C6920 Industrial PC running TwinCAT NC PTP software and Windows CE operating system along with EtherCAT as the I/O and drive fieldbus. For the HMI, E.A.R.L. is equipped with a Beckhoff CP6901 12” Control Panel display with touch screen and visualization functions developed with TwinCAT software. “PC-based control has been the preferred automation platform of ARM Automation for several years,” Grupinski explained. “We typically avoid traditional PLC vendor platforms due to the exorbitant net cost to use them for more complex systems.”
There are 11 options for configuring different throws via the HMI to adjust speed and pick-up orientation. The E.A.R.L. robot with Beckhoff controls can be reconfigured for completely different parameters in 10 seconds or less.
ARM Automation has been an active member of the EtherCAT Technology Group (ETG) for years and has developed EtherCAT slave devices. “EtherCAT was the deciding factor in our automation and controls approach for E.A.R.L.,” said Joe Geisinger, CTO, ARM Automation. “The system delivers optimum synchronicity and precision for multi-axis systems using its Distributed Clocks (DC) feature. Without that tight synchronicity where every device is taking the same set points at the same time, ‘ticks’ can develop in the controls. On a multi-axis system this results in unwanted vibration.”
The precision inherent to EtherCAT enabled ARM Automation to coordinate the external I/O with the control and position of the drives in the sub-millisecond range. The position of the E.A.R.L. robot’s end effector is communicated to the EtherCAT drives to determine the exact time at which the ball needs to be released. That position measurement is exceptionally precise, within 1 ms, and successfully creates the correct loft of the ball each time. E.A.R.L. is able to release a bowling ball under test within 250 µs of a scan of the position.
The open architecture of EtherCAT supports a wide range of fieldbuses. “It easily ties into multiple I/O platforms, however, EtherCAT can still connect to SERCOS devices via mini SERCOS fieldbus card factory installed on the Beckhoff C6920 IPC, which provides added flexibility,” Geisinger said. “EtherCAT also allows us to diagnose the bus to detect broken links on the physical layer and easily determine exactly where the problem is located along the line.”
“Traditionally ARM used SERCOS for high-end servo systems, but switched to EtherCAT years ago for several reasons,” Grupinski said. “These include: a common physical layer, a drastic increase in performance, declining interest in legacy fieldbuses and increasing interest in Ethernet-based networks and the ability to combine motion and I/O on same network.”
“E.A.R.L. required the ability to flexibly gather the inputs from a wide range of devices and communicate easily with the drives in one flexible environment,” Geisinger added. “TwinCAT System Manager and EtherCAT allow us to do just that – we can pull together different platforms easily. With this system, we can also run multiple tasks such as the I/O and drives at different scan rates which provided a significant efficiency boost.”
ARM Automation used the TwinCAT software platform to develop the robot motion controller and to coordinate the acquisition of I/O and position data from the drives, perform inverse kinematics, generate the next joint position commands, and output the new position commands and data to the drives. “We utilized the path programming functionality within TwinCAT for the multi-axis platform on E.A.R.L.,” Geisinger explained. “With NC PTP, we control the motion axes and constantly monitor the status of the EtherCAT drives.”
There’s also a complete safety system implemented in E.A.R.L. and TwinCAT monitors all the safety devices. If anything happens to go wrong during operation, the drives are disabled and the robot immediately goes into a safe state until the system is reset properly. E.A.R.L. is also enclosed in a protective cage with safety sensors, light curtains and safety relays installed all around to ensure optimum safety.
EtherCAT and PC-based control bowl a 300
“We now have more options and better resolution for release height, trajectory, ball speed, RPM’s, and loft,” USBC’s Stremmel remarked. “E.A.R.L is able to handle a larger range of ball diameters, and RPMs. Moving E.A.R.L and changing his settings is much simpler and far more accurate than our previous robot solution.”
“In addition to the E.A.R.L. ball release accuracy within 250 µs, using EtherCAT has probably eliminated a week’s worth of debugging for the E.A.R.L. robot when compared with almost any other system,” Geisinger reported. “This is because EtherCAT is very easy to integrate and is exceptionally robust. One EtherCAT network can connect to five other fieldbuses all on one control platform and one cable if necessary. If there are specific devices required that must operate on different fieldbuses, the ability to bring all these into a single environment in EtherCAT and TwinCAT is a huge benefit and keeps the system networking as tightly integrated as possible.”
“Naturally, in performing such a wide range of work in challenging applications, ARM constantly combs the automation industry for new tools and innovative processes to enhance our solutions,” said Grupinski. “With E.A.R.L. as an obvious example, our applications are inherently complex and are often highly custom in nature, requiring flexible control platforms that can be configured on-demand to suit our customers’ needs.  Beckhoff's open and modular controls architecture provides ARM Automation just the right toolbox to rapidly develop solid customized solutions,” he concluded.
With the bowling research revolution initiated by E.A.R.L., the USBC has another leading edge tool to help uphold the game’s credibility, preserve its future and enhance the bowling experience for millions.
Video: EARL the bowling robot
For more information:
ARM Automation
Beckhoff Automation
E.A.R.L. testing parameters and specifications
Ball Laydown (Y axis)
Release Point (X axis)
Release Height (Z axis)
Ball Speed
Ball Weight
Spin Velocity
Tilt of Spin Axis
Rotation of Spin Axis
Spin axis VS Ball frame (α)
Spin axis VS Ball frame (β)
Source: ARM Automation

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