Muscles vs. Machines: Another Round of Field Tests in Catheys Valley

Our team recently took a second trip to Catheys Valley, where hilly terrain and sunny weather gave us the perfect conditions for another productive trial run day! This time, our goal was to find out how long and physically strenuous different wood waste removal scenarios might be for the average person. 

During our last visit, our robot was put to the ultimate test, as we hadn’t used it on mountainous ground before. We were thrilled to see it perform very well despite the natural obstacles in the new environment. For this round of testing, the focus shifted to the amount of labor and time a person might experience while hauling wood waste both with and without an assistive robot. Our hope was to collect data that could provide insight into just how much labor our robot would be saving wood waste removal workers in the field. 

Figure 1. Setting up for the day among woolly wonderful company!

We ran through five scenarios in total, each spanning 600 feet. Our graduate engineer and main test subject, Rodolfo, completed each trial while wearing a Fitbit to monitor his heart rate. We also timed each activity and had Rodolfo rest between runs until his heart rate returned to around 85 bpm, his baseline.

Here’s what we found:

Figure 2. Table detailing each of our five trials.

Figure 3. Rodolfo walking with the robot following (Trial 2).

As shown in the table, Rodolfo took significantly longer to complete the walking trial with the robot following him because they were going back and forth along a short 100-foot path, making lots of turns. Despite the added time, the robot didn’t significantly increase physical strain, as Rodolfo’s heart rate remained close to baseline. In contrast, manually pushing heavier loads clearly required more effort, with the 110-lb trial causing the highest spike in heart rate. These findings help demonstrate both the physical toll of wood waste removal and the promise of robotic assistance in easing that burden.

Before our final trial, we had planned to time the robot while it pulled a heavy cart, but we hit a snag when its 3D-printed trailer hitch snapped. Our spare hitch also ended up cracking when we attempted to secure it onto the back of the robot, and it wouldn’t fit properly. As a result, we had to abandon plans for further testing with the robot during this trip. While this was a bit disappointing, it didn’t stop us from collecting valuable data on just how physically demanding these tasks can be for a person working alone. 

This second round of field testing in Catheys Valley gave us exactly what we came for: a clearer picture of the physical demands involved in wood waste removal and how our robot can help relieve them. While there will always be unpredictable setbacks along the way, each one offers a chance to learn, adapt, and keep moving forward. Most importantly, our findings reinforce our belief that with continued refinement, such as improving the robot’s ability to handle turns, this assistive technology has real potential to reduce the physical strain and labor involved in forest management jobs like thinning.