asimo

Introduction
Want a robot to cook your dinner, do your homework, clean your house, or get your groceries? Robots already do a lot of the jobs that we humans don't want to do, can't do, or simply can't do as well as our robotic counterparts. In factories around the world, disembodied robot arms assemble cars, delicately place candies into their boxes, and do all sorts of tedious jobs. There are even a handful of robots on the market whose sole job is to vacuum the floor. Many of us grew up watching robots on TV and in the movies: There was Rosie, the Jetsons' robot housekeeper; Data, the android crewmember on Star Trek TNG; and of course, C3PO from Star Wars. The robots being created today aren't quite in the realm of Data or C3PO, but there have been some amazing advances in their technology. Honda engineers have been busy creating the ASIMO robot for more than 17 years. In this article, we'll find out what makes ASIMO the most advanced
WHAT IS ASIMOS??
ASIMO, which stands for Advanced Step in Innovative Mobility, was developed by the
Honda Motor Company and is the most advanced humanoid robot in the world. According to the ASIMO Web site, ASIMO is the only humanoid robot in the world that can walk independently and climb stairs. While there are several other humanoid robots that can walk, none have the smooth, realistic gait that ASIMO has.
In addition to ASIMO's ability to walk like we do, it can also understand some spoken commands (currently only in Japanese) and recognize faces. ASIMO has arms and hands so it can do things like turn on light switches, open doors, carry objects, and push carts.
HONDA’ VISION OF ASIMOS
Rather than building a robot that would be another toy, Honda wanted to create a robot that would be a helper for people -- a robot to help around the house, help the elderly, or help someone confined to a wheelchair or bed. ASIMO is 4 feet (1.2 meters) high, which is just the right height to look eye to eye with someone seated in a chair. This allows ASIMO to do the jobs it was created to do without being too big and menacing. Often referred to as looking like a "kid wearing a spacesuit," ASIMO's friendly appearance and nonthreatening size work well for the purposes Honda had in mind when creating it.
ASIMO'S MOTION: BUILT LIKE A HUMAN
Honda researchers began by studying the legs of insects, mammals, and the motion of a
mountain climber with prosthetic legs to better understand the physiology and all of the
things that take place when we walk -- particularly in the joints. For example, the fact that we shift our weight using our bodies and especially our arms in order to balance was very important in getting ASIMO's walking mechanism right. The fact that we have toes that help with our balance was also taken into consideration: ASIMO actually has soft projections on its feet that play a similar role to the one our toes play when we walk. This soft material also absorbs impact on the joints, just as our soft tissues do when we walk. ASIMO has hip, knee, and foot joints. Robots have joints that researchers refer to as "degrees of freedom." A single degree of freedom allows movement either right and left or up and down. ASIMO has 26 degrees of freedom spread over different points of its body in order to allow it to move freely. There are two degrees of freedom in ASIMO's neck, six on each arm and six on each leg. The number of degrees of freedom necessary for ASIMO's legs was decided by measuring human joint movement while walking on flat ground and on stairs. ASIMO also has a speed sensor and a gyroscope sensor mounted on its body. They perform the tasks of:
• sensing the position of ASIMO's body and the speed at which it is moving
• relaying adjustments for balance to the central computer
These sensors work similarly to our inner ears in the way they maintain balance and orientation. To accomplish the job our muscles and skin do in sensing muscle power, pressure and joint angles, ASIMO has both joint-angle sensors and a six-axis force sensor


ASIMO'S MOTION: WALKS LIKE A HUMAN

Unless you know a lot about robotics, you may not fully grasp the incredible milestone it is that ASIMO walks as we do. The most significant part of ASIMO's walk is the turning
capabilities. Rather than having to stop and shuffle, stop and shuffle, and stop and shuffle into a new direction, ASIMO leans and smoothly turns just like a human. ASIMO can also self-adjust its steps in case it stumbles, is pushed, or otherwise encounters something that alters normal walking. In order to accomplish this, ASIMO's engineers had to find a way to work with the inertial forces created when walking. For example, the earth's gravity creates a force, as does the speed at which you walk. Those two forces are called the "total inertial force." There is also the force created when your foot connects with the ground, called the "ground reaction force." These forces have to balance out, and posture has to work to make it happen. This is called the "zero moment point" (ZMP).
To control ASIMO's posture, engineers worked on three areas of control:
• Floor reaction control means that the soles of the feet absorb floor unevenness while still maintaining a firm stance.
• Target ZMP control means that when ASIMO can't stand firmly and its body begins to fall forward, it maintains position by moving its upper body in the direction opposite the impending fall. At the same time, it speeds up its walking to quickly counterbalance the fall.
Foot-planting location control kicks in when the target ZMP control has been activated. It adjusts the length of the step to regain the right relationship between the position and speed of the body and the length of the step.

ASIMO'S MOTION: SMOOTH MOVES

ASIMO can sense falling movements and react to them quickly; but ASIMO's engineers.
wanted more. They wanted the robot to have a smooth gait as well as do something that

other robots can't do -- turn without stopping. When we walk around corners, we shift our center of gravity into the turn. ASIMO uses a technology called "predictive movement control," also called Honda's Intelligent Walking Technology, to accomplish that same thing. ASIMO predicts how much it should shift its center of gravity to the inside of the turn and how long that shift should be maintained. Because this technology works in real time, ASIMO can do this without stopping between steps, which other robots must do. Essentially, with every step ASIMO takes, it has to determine its inertia and then predict how its weight needs to be shifted for the next step in order to walk and turn smoothly. It adjusts any of the following factors in order to maintain the right position:
• the length of its steps
• its body position
• its speed
• the direction in which it is stepping
Now let's talk about another one of ASIMO's talents: recognizing images.
bb
In robotics, vision is a captured image that is interpreted based on programmed templates. In a manufacturing environment, where robotic arms build cars or robots inspect the microscopic connections on semiconductor chips, you're dealing with a controlled environment. The lighting is always the same, the angle is always the same, and there is a limited number of things to look at and understand. In the real (and unstructured) world, however, the number of things to look at and understand increases greatly. A humanoid robot that must navigate through homes, buildings, or outdoors while performing jobs must be able to make sense of the many objects it "sees." Shadows, odd angles and movement must be understandable. For example, to walk on its own into an unknown area, a robot would have to detect and recognize objects in real time, selecting features such as color, shape, and edges to compare to a database of objects or environments it knows about. There can be thousands of objects in the robots "memory."
ASIMO's vision system consists of basic video cameras for eyes, located in its head. ASIMO uses a proprietary vision algorithm that lets it see, recognize, and avoid running into objects even if their orientation and lighting are not the same as those in its memory database. These cameras can detect multiple objects, recognize programmed faces, and even interpret hand motions. For example, when you hold your hand up to ASIMO in a "stop" position, ASIMO stops. The facial recognition feature allows ASIMO to greet "familiar" people. The cameras also relay (via USB) what ASIMO sees to ASIMO's controller. That way, if you're controlling ASIMO from a PC, you can see what ASIMO sees.
CONTROLLING ASIMO
ASIMO is not an autonomous robot. It can't enter a room and make decisions on its own
about how to navigate. ASIMO either has to be programmed to do a specific job in a specific area that has markers that it understands, or it has to be manually controlled by a human. ASIMO's "backpack" carries the computer (a.k.a. brain) that controls ASIMO's movement. ASIMO can be controlled by three methods:
• PC
• Wireless controller (sort of like a joystick)
• Voice commands
Using 802.11 wireless technology and a laptop or desktop computer, you can control ASIMO as well as see what ASIMO sees via its camera eyes. ASIMO can also use its PC connection to access the Internet and retrieve information for you, such as weather reports and news. The wireless joystick controller operates ASIMO's movements the same way you would operate a remote-control car. You can make ASIMO go forward, backward, sideways, diagonally, turn in place, or walk around a corner. Making ASIMO move by remote control may not seem that advanced, but ASIMO does have the ability to self-adjust its steps. If you have it walk forward, and it encounters a slope or some sort of obstacle, ASIMO automatically adjusts its steps to accommodate the terrain. There are also preprogrammed gestures that can be selected using buttons on the controller. These include things like waving, grasping, and responding in other ways. ASIMO's ability to understand voice commands is the newest addition for control. Its database includes about 30 different spoken commands that activate certain movements in ASIMO's repertoire.
In addition to the voice commands for controlling ASIMO's movements, there are also spoken commands to which ASIMO can respond verbally. This is the feature that has made it possible for ASIMO to work as a receptionist, greeting visitors and answering questions.
ASIMO'S POWER
Like most other technologies in the robotics field, ASIMO is powered by servo motors.
These are small but powerful motors with a rotating shaft that moves limbs or surfaces to a specific angle as directed by a controller. Once the motor has turned to the appropriate
angle, it shuts off until it is instructed to turn again. For example, a servo may control the
angle of a robot's arm joint, keeping it at the right angle until it needs to move, and then
Controlling that move. Servos use a position-sensing device (also called a digital decoder) to ensure that the shaft of the motor is in the right position. They usually use power proportional to the mechanical load they are carrying. A lightly loaded servo, for example, doesn’t use much energy. ASIMO has 26 servo motors in its body that move its arms, hands, legs, feet, ankles, and other moving parts. ASIMO manages a series of servo motors to control each kind of movement.

BATTERIES REQUIRED
ASIMO is powered by a rechargeable, 40-volt, nickel-metal hydride battery that lasts for 30 minutes on a single charge. The battery is stored in ASIMO's mid-section, where its weight also helps create ASIMO's center of balance. ASIMO's battery takes four hours to fully charge, so a second (and third) battery is crucial if you needed ASIMO to operate for very long.
ASIMO'S PEERS
In addition to ASIMO, there are some other pretty sophisticated humanoid robots out there that appear to do a lot of the same things (except for the smooth turning). The difference is that most of them are built on a much smaller scale and are intended more for entertainment than service. Right now, ASIMO's greatest competition in terms of technology seem to be:
• SONY's QRIO robot
• Fujitsu's HOAP-1 robot
• Dr. Robot
There are also two different robots used in hospitals around the world that navigate hallways and take elevators to deliver patient records, x-rays, medicines, and other things all over the hospital. They travel on wheels and are programmed to identify and follow markers and bar codes placed on the walls.
ASIMO'S LIFE STORY
Honda began development of its humanoid helper robot in 1986. Honda engineers knew the robot had to be able to easily navigate around a house or building, and that meant the
walking technology had to be perfect. Therefore, their first attempts were basically boxes
with legs. Once the walking mechanism was mostly developed, arms, hands and finally a
head were added.
THE ASIMO TIMELINE
• 1986 - Static walking
the first robot Honda built was called EO. EO walked very slowly, taking sometimes 20 seconds to complete a single step. This was because EO did what was called "static walking." In static walking, after the robot begins moving one foot forward, it has to wait until it has its weight balanced on that foot before it begins to move the other foot forward. Humans don't walk that way, so the research continued.
• 1987 - Dynamic walking
by now engineers had developed a method for "dynamic walking," which is much more human-like. With this walking technology, the robot (now called prototype E1, soon followed by E2 and E3 as research progressed) leaned into the next step, shifting its weight and moving the other foot forward to catch itself so that rather than falling forward, it walked forward.
• 1991 - Walking like a pro
In prototypes E4, E5 and E6, Honda's engineers perfected the walking mechanism to the point where the robot could easily walk on an incline, up stairs, and on uneven terrain. Because truly walking as a human does actually requires the use of the body, arms, and head, engineers had to move on to the next step and add the rest of the body.
• 1993 - A more human-looking robot
with a body, arms, hands and a head, the next generation of prototypes (P1, P2 and P3) looked more like a "humanoid." P1, however, was a looming 6 feet 2 inches (188 cm) tall and weighed 386 pounds (175 kg). P2 was scaled down slightly in height, but weighed an even heavier 463 pounds (210 kg) -- not something you want stepping on your toes in the kitchen. But, it could walk very well on uneven surfaces, inclines, and could even grasp objects and push carts. P2 could even maintain its balance when pushed. Finally, P3 was built at a more comfortable (and less frightening) 5 feet 2 inches (157 cm) tall. Weighing 287 pounds (130 kg), P3 could walk faster and more smoothly than its predecessors.
• 1997. The ASIMO we know
even more improvements had been made to the walking system, allowing ASIMO to walk gracefully and easily in almost any environment. Sophisticated hip joints allowed ASIMO to turn smoothly -- something other robots have to stop and shuffle in order to do. In thinking about how ASIMO was to be used, the engineers made the decision to further reduce ASIMO's size to 4 feet (122 cm) so that not only would it not be intimidating to people who were seated (or standing, for that matter), it would actually
1. Be at eye level. This height also made it possible for ASIMO to work at table height or at a computer, reach light switches and turn door knobs. ASIMO's very strong but lightweight magnesium-alloy body, covered in plastic "skin," weighed in at only 115 pounds (52 kg).
Technology called "predicted movement control" allowed ASIMO to predict its next movement automatically and shift its weight to make a turn. ASIMO's stride could also be adjusted in real time to make it walk faster or slower. P2 and P3 had to use programmed walking patterns.
Robots are and have been in use in many areas since the 1960s. With computer processors getting increasingly more powerful and technology in robotics expanding into new areas, it won't be long before we do have a "Rosie" to cook our meals and clean our houses. For more information on ASIMO and other robots, as well as the technological advances that make humanoid robots possible.