110 km and Counting

AMOS was back at Woolastook for a few days last week, but I think its days on the water will be coming to a close soon for this year. The temperature is getting down near zero in the mornings, and the lead acid battery that I'm currently using doesn't seem to last as long in cold weather. I have been looking at bigger lithium phosphate batteries, perhaps 50 or even 100 AH but they are pretty expensive, so I'll first need to make sure that AMOS is sufficiently mobile with carrying the extra weight, and make a request to In Nature Robotics' finance department. 😏

To date this year, AMOS has traveled 110 km, mostly near Woolastook Park, but some around Cap-Brûlé too. Almost all of it has been autonomous, travelling to pre-programmed GPS coordinates. The 1000 km distance goal I came up with on New Year's day isn't going to happen this year, but all of the testing done so far has highlighted a number of issues that can be solved to help make AMOS a better robot:

• Need to guard against AMOS getting stuck. Some areas of the shore are more amenable to docking than others. Safe points (with maximal sun exposure and not too close to populated areas) were defined in the software for AMOS to try to reach whenever its battery gets low, but sometimes AMOS is too far away from a safe point when a low battery condition occurs, and it must go into low power mode wherever it happens to be at the time. The wind then eventually blows the boat to a random shore location, where it often becomes beached on rocks, or stuck in a shoreline tree or bush. One solution might be to have an anchor system that lets down a small anchor with say a 5 m line. This would hopefully keep the boat in a stable location well enough away from shore to get going again after its battery charges back up.
• Need to look more closely at the LiDAR obstacle avoidance code. Sometimes it seems to be working, but at other times I've seen AMOS veer off directly toward a clump of grass onto the shore, and I'm like, "what the heck?".
• Need to fix up the sensor deployment arm to avoid it getting tangled on electrical cables on the back deck. Sometimes the sensor probes don't quite make it to the surface of the water.
• Need to re-wire the electronics for sleep mode to switch off absolutely everything that doesn't need to be powered. Currently AMOS requires about 2.5 W in sleep mode, but I think I should be able to get this down to close to 0.5 W by only powering the RF220SU radio board, and the solar charge controller. 

A lack of sun and cold weather kept AMOS from getting too far this past week, but here is some temperature data for Sept. 26 to 28 (http://arcg.is/uTS90):