Life Cycle Testing Machine
The Life Cycle Testing Machine was my first project as an intern for the Retail Solutions team at HP. This was also the first major project that I took on by myself, which was an interesting, yet rewarding challenge as the only engineering intern in the department.
BACKGROUND
When I was first joined Retail Solutions, the HP Engage Go was a newly released product. The HP Engage Convertible System is comprised of two major components: the HP Engage Go Mobile System and the HP Engage Go Dock. It is designed to allow the user to move onto the sales floor with the HP Engage Go Mobile System, while leaving the HP Engage Go Dock at the POS station. This reinvented retail experience gives the retailer more freedom to interact with the customer, while still having the option of a convertible POS system. The custom docking connectors are an HP patented solution, engineered uniquely for the HP Engage Go and are integral to the two systems working together in unison. The connectors were developed to reliably pass all USB signals and power throughout the system and if they do not work properly, the product will no longer be functional.
PROBLEM
In order to ensure that these docking connectors could withstand the harsh retail and hospitality environments, a fixture was designed and built to automatically dock and undock the tablet. However, this machine could only carry out vertical motion, meaning the tablet and docking column were perfectly lined up and the tablet was simply lifted off the dock, then seated back on. Due to this limited motion, the device did not provide an accurate lifetime of the docking connectors as it did not take into account the variability and error that is presented when a human docks the tablet. Furthermore, this fixture was unnecessarily large and bulky and cost thousands of dollars to build. Photos of this testing device can be seen below.
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SOLUTION
My main goal for this project was to build a smaller, cheaper device that would provide a more accurate lifetime of the product. Humans are far less precise than machines are, therefore it was important to introduce varying degrees of "error" by creating translational and angular offsets. With access to the HP Multi Jet Fusion 3D printer, I was able to use rapid prototyping techniques for this project, promoting an iterative design process.
The device consists of several different components, each with their own specific purpose. To start, the HP Engage Go Dock is placed in the center of the device and the HP Engage Go Mobile System is screwed into the tablet encasing. The encasing is attached to a rigid plate with rubber grommets. When the HP Engage Go Mobile System is agitated or moved, the rubber grommets cause it to wobble, presenting randomness to the system to mimic compliance. The plate that holds the rubber grommets in place is screwed to three linear actuators, which are placed 120° from one another. These linear actuators are responsible for the docking and undocking motion of the tablet from the dock. This system sits two rails, one that allows for motion to the right and left and one that allows for motion forward and backward. Each rail is attached to a linear actuator so that the translation can be specified in any direction for repeatable positional offsets.
Front
Side
Back
RESULTS
Although the offsets produced by the Life Cycle Testing Machine are very slight, the small amount of error affects the docking greatly and gives HP the opportunity to make more accurate predictions about the lifetime of the custom docking connectors. Almost the entirety of the device was 3D printed, costing about one tenth of the original HP Engage Go testing machine. These cost savings, as well as the more compact design gives the Retail Solutions team the opportunity to invest in more life cycle robots to test more systems at once. Finally, the more realistic docking and undocking process created by the Life Cycle Testing Machine will shine light on issues that may not have been considered beforehand, allowing the company to gain insight on better improvements for future generations of the HP Engage Go.
