The vision for the future soldier is to be combat effective and also highly mobile, adaptive, networked, sustainable with total battle space situation awareness and information assurance. Therefore, he is equipped with night- vision goggles, radios, smartphones, GPS, infrared sights, a laptop as well as batteries to power them. He is also burdened with ammunition, gear interface, body armor, boots, weapons and water. The weight carried by today’s Army infantry fighters or “marching load” is more than 120-pounds, and can reach as much as 132-pounds.
The DARPA has identified “reducing the soldier’s logistic burden” as one of its key scientific and technological priority. Towards this end, DARPA placed a $32 million, two-and-a-half-year contract Google Inc.’s Boston Dynamics, of Waltham, Massachusetts to develop a robotic mule. The mule also called “AlphaDog” is able to carry 400 pounds (181 kgs) of backpacks and other equipment for up to 20 miles over 24 hours. Its barrel shaped body allows it to roll over if it falls. DARPA also envisions it as a mobile recharging station for US troops.
Marine Corps Shelves Futuristic Robo-Mule Due to Noise Concerns
The robo-mule was put to operational tests during summer 2014 at Rim of the Pacific, the largest military exercise in the Pacific region. Marines performed various tests to demonstrate its ability for patrols on rugged grounds and respond to commands. The BigDog must be able to demonstrate its ability to complete a 20-mile trek within 24 hours without refuelling while carrying a load of 400lbs.
But the experiment also exhibited the shortcomings of the prototype, Kyle Olson, a spokesman for the Warfighting Lab, told Military.com. “As Marines were using it, there was the challenge of seeing the potential possibility because of the limitations of the robot itself,” Olson said. “They took it as it was: a loud robot that’s going to give away their position.”
The US Marine Corps has halted its use of a mule‐like robot designed to carry 400 or more pounds and follow human commands. The robot, borne of a partnership between Google and the Pentagon’s research arm, turned out to be unsuitable for missions. The Legged Squad Support System ﴾LS3﴿ has been put “in storage, with no future experiments or upgrades planned,” according to a report by Military.com.
DARPA LS3 Robot Mule follows its leader through rough terrain
A soldier operates the machine by strapping a sensor to his/her foot and the LS3 automatically follows them using computer vision, so there is no need for a dedicated driver.
A pair of stereo cameras mounted into the ‘head’ of the robot, integrated alongside a light detecting and ranging (LIDAR) component with vision software creates accurate 3D model of the terrain allowing it to navigate in the rough terrain. This model enables the robot to identify a safe path forward, but can also enable BigDog to calculate the distances of any gaps or caverns and whether or not they could be cleared safely with a jump. In laboratory testing, the BigDog successfully jumped 1.1 metres with a full payload.
BigDog’s unique walking pattern is controlled through four legs, each equipped with four low-friction hydraulic cylinder actuators that power the joints. Built onto the actuators are sensors for joint position and force, and movement is ultimately controlled through an onboard computer which manages the sensors.
The robot can also estimate the ground plain of rough terrains using a history of leg kinematic data and odometry which is recorded and stored in the onboard computer, whilst using traction control in order to avoid, detect and recover from foot slips on uneven surfaces.
Approximately 50 sensors are located on BigDog. These measure the attitude and acceleration of the body, motion and force of joint actuators as well as engine speed, temperature and hydraulic pressure inside the robot’s internal engine. Low-level control, such as position and force of the joints, and high-level control such as velocity and altitude during locomotion, are both controlled through the onboard computer.
As a result, BigDog has a range of locomotion behaviors and speeds that can be demonstrated. Through control of its four legs, the robot can stand up, squat down, walk with a crawling gait, trot with a running gait and even bound in a gallop gait. Although the average speed for a trot is approximately 3.5mph, BigDog exceeded 7mph while bounding in laboratory testing.
DARPA’s robotic mule Legged Squad Support System or LS3, was capable to follow its leader through wooded areas autonomously.
The BigDog is controlled by a human operator via an operator control unit (OCU) that communicates actions to the robot through IP radios. Alpha Dog was constantly being improved with higher and higher autonomy features.
The ‘hearing’ sensors have been integrated, enabling LS3 to understand and obey about ten different kinds of voice commands that can be combined in different ways, like “follow,” “stop,” “sit,” “stay,” and “roll over.” In addition, it has many more impressive features like:
- LS3 can navigate by following GPS waypoints autonomously even under night conditions.
- In addition to human following and GPS navigation, LS3 can also follow distance and a direction command.
- LS3 can detect vegetation, and can plow through five-foot-high bushes while avoiding obstacles like rocks.
- The robot is also much quieter than earlier versions with noise levels of 70 decibels, which puts it at the passenger car / vacuum cleaner level.
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