SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  A10-134 (Army)
Title:  JP-8 Hydraulic Power System for Legged Robot
Research & Technical Areas:  Air Platform, Ground/Sea Vehicles

Acquisition Program:  PEO Ground Combat Systems
  Objective:  30-45kW power system consisting of high power density diesel and/or JP-8 engine, fuel consumption less than 0.66lb/kW*hr and weigh less than 110 lbs. for the purpose of powering a hydraulic pump at 6000 rpm for legged robot mobility.
  Description:  Military robots have great advantages and are needed for a vast array of tasks in environments around the world. The rough mountainous terrain found in Afghanistan and other areas in the world demand alternatives to tracked and wheeled robotic mobility. Legged robots are able to navigate rocky, off-road conditions including steps, boulders, etc. This kind of mobility has much better performance when utilizing a hydraulic-driven system. This is due to high torque transients and the irregularity of motion. TARDEC Intelligent Ground Systems has built a gasoline powered, hydraulic driven legged robot named the Big Dog and has had huge success in its demonstration. TARDEC is building a larger, more capable robot named the Gen. II Big Dog and is in need of a diesel and/or JP-8 power system for it. The robotic system has limits on fuel consumption and weight. The power system would be designed to mate to a hydraulic hydraulic pump. This would also have its purpose an a non-primary power source for larger military vehicles. Currently, most/all Auxiliary Power Units (APUs) and Gensets provide only electrical power; a non-primary hydraulic power unit would be useful for vehicles with hydraulic loads (turret drives, etc.). Also, the Army fields thousands of smaller construction vehicles, which utilize hydraulic power to move, lift, pull, push, and turn attachments. These vehicles could directly utilize this high power-density technology. Hydraulic systems are on many commercial vehicles, both where this size of a power system could be considered non-primary or primary - forklifts, Bobcats, cement trucks, construction lifters, etc.

  PHASE I: Design a power unit that meets the objectives of the above description. Using modeling and simulation, validate the design.
  PHASE II: Develop the drive designed in Phase I. Validate the design and the modeling and simulation through testing. Measure system hydraulic pressure as a result of transient load changes such as piston movements. Demonstrate the drive on a military legged robot.

  PHASE III: Hydraulic systems are on many commercial vehicles, both where this size of a power system could be considered non-primary or primary - forklifts, Bobcats, cement trucks, construction lifters, etc.

  References:  ttp:// Springer Handbook of Robotics. Siciliano, Bruno & Khatib, Oussama. IEEE, 2008.

Keywords:  engine, hydraulic, power, jp-8, diesel, robot, light, non-primary

Questions and Answers:
Q: You are looking for the engine and hydraulic system, correct?
A: The main focus of this SBIR is the development of a heavy fuel engine. The hydraulic system is secondary. Please apply focus more on the heavy fuel engine.
Q: Is it to be concluded that a 60 hp heavy fuel engine providing a final output @ 6,000 rpm and weighing up to 110 lbs, provided the BSFC specified, is nowhere available off the shelf?
A: Yes.
Q: 1. Is there a rectilinear cube into which the new engine must fit?
2. Is there any highly critical dimension, or is there flexibility?
A: No critical dimensions at this point; there is shape flexibility.
Q: 1. What is the weight, GPM and the output pressure of the hydraulic pump that would be running at 6000rpm?
2. Could it be a lower rpm?
We have an engine design that outputs hydraulic direct, no need for the pump and the engine.
A: 1. Weight, GPM, and output pressure of hydraulic pump is unknown at this time.
2. Hydraulic pump speed listed is not imperative - lower rpm is acceptable.

Q: 1. Is there a preference for a constant speed/variable load or a variable speed/variable load engine?
2. Do you have a max lag time for hydraulic load response?
3. Are you including the accessory systems in the engine mass: Starter/alternator/exhaust? Tilt angle capacity?
4. Are lower speed engines that meet the target power acceptable?
A: 1. Variable speed & load engine is preferred.
2. No max response time.
3. Engine accessories are included in engine mass - they are absolutely necessary for unit to operate and meet requirements.
4. Yes - lower speed engines are acceptable.

Q: 1. Is the fuel economy a composite, or a Not-to-Exceed value of a specific cycle?

2. Regardless, what test cycle is the fuel economy measurement based on?
A: 1. The fuel economy number is a not-to-exceed value. At rated power, the engine shall not exceed that fuel economy value.

2. The fuel economy value is based on the Gen. II Big Dog expected range, the size of its fuel tank, and the estimated duty cycle of the vehicle.
Q: Is there a preferred cooling strategy (i.e. liquid or air cooled)?
A: No there is no preferred cooling strategy.

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