ETQ TG1200: Final Fuel Consumption Measurements/Analysis

Preliminary fuel consumption measurements for the ETQ TG1200 gasoline generator operating in the 0 to 600W range were published on 2009-12-23, along with a background of gasoline generator theory as applied to the TG1200. The interim has brought additional measurements and improved statistical analysis.  The fuel consumption [c] as a function of instantaneous power output [w] has been verified as reasonably linear [c(w)=pw+i] with idle consumption i=0.0830 gallons/hour, proportional consumpti...

ATR5-b1: Steering winch spool mount

Steering wheels are ubiquitous, effective, and easy to take for granted. In the absence of power steering, they deliver an enormous force -- 400 pounds (1.8kN) in the case of ATR5 -- to rotate the front wheels with a user input of only 20 pounds (89N). Unlike other actuation points that interact only with the vehicle itself -- throttle, gearshift, clutch, ignition -- the steering wheel is directly affected by the unpredictable environment. A vehicle running smoothly at top speed across cemen...

ATR5-b1: Framework

ATR3-b1's framework corner angles are imperfect. Welding the corners into permanent angles is one obvious solution, but welding is a complex art and the initial equipment expenses are high: $700 - $1300 for a MIG welder and necessary supplies.  Though a weldless build is realistically limited in strength and size, bolt-based designs only require a drill press and a pile of bolts/washers/nuts. But how to build a 3-dimensional right angle with only bolts, which allow rotation about their axes?...

Power Sources 2, or, Why ATR5 is powered by two combustion engines

Small garden tractors, such as ATR5-b0, are not designed to support heavy electrical loads.  Their engines contain integrated alternators to power headlights and maintain the starter SLA, with an output around 40 watts.  This might be sufficient for logic electronics, but actuation and lighting add at least 50 to 100 average watts.  Even optimally efficient CFL or LED headlights will add 35 watts, and the physical actuators (especially steering) will add another 30 to 60W average.  [For instance...

A* Pathfinding

From Fabrice Rossi, a simple visualization of A* vs Dijkstra pathfinding over XML-defined maps. Pictured is a terrain area that ATR5 will be expected to traverse. Green (foliage), black (structures), and purple are impassable. Grey is leveled roadway, which is less costly to traverse than unleveled ground (white). Both paths begin at a point just north of the smaller structure (black block). Note that moving the goal a few meters southwest shifts the optimal path around the southernmost treerow....

DieHard 27582 SLA unverified capacity function

Sears sells the DieHard model 27582 marine (deep cycle) battery for $130 (excluding core deposit). This is probably the cheapest chemical (Sealed Lead Acid or SLA) battery in its size range on the market in terms of initial cost ($ per Peukert capacity).  The 27582's total power output is not obvious, given that SLA discharge efficiency varies depending on instantaneous output current, significantly affecting the runtime between charges. The Peukert capacity C is defined as the total amp-...

ETQ TG1200: Preliminary Fuel Consumption Measurements

Unlike chemical batteries, gasoline generators consume a minimum amount of fuel even at zero current draw. [The battery equivalent is the inverter idle current, but this is typically only a few watts.] To a first approximation, internal combustion generator fuel consumption (liters per hr, c) as a function of energy output (kW, w) is linear [c(w) = pw + i], where the power-proportional consumption (p) and idle consumption (i) tend to be inversely proportional.  Manufacturers usually advertise on...