- Materials & Industrial Technology
The Fascinating World of Walking Machines
Practical walking machines exist and perform various roles
Over the decades, the walking machine has leaped from the imagination of science fiction to the world of practical reality.
They are becoming increasingly abundant and take on forms from the experimental eight, six, four and two legged varieties. They range in size from the small, toy versions to the monstrous. These are the walking machines that can negotiate any raw territory, like forests where the lumbering machine (no pun intended) working at a logging operation, to Asimo, the fully autonomous Japanese robot that can walk up and down stairs and do a lot of other two legged human activities. This exciting technology can be used for the benefit of humanity, but it also has a dark side, as instruments of war and terror. They are already in use by industry, in entertainment, experiment and some say, now in warfare, but that is yet to be verified. All other considerations are real.
The basic components of a fully functional piloted or autonomous walking machine consists of a computer controller, hydraulics, an engine, mechanical parts, fully articulated legs and feet, flexible joints and springs and controls for a human operator in the larger machines. The concept of the walking machine is to function like their biological counterparts, but as a true electromechanical machine using metal and manufactured components. Many studies have been done to find the best configuration for a walking machine. Thus far, the six and two legged variety have been the most successful and are deployed in the field.
The computer control is essential for the timing the resonant rhythm needed to work the legs, keep the machine balanced and to prevent tipping. Coupled with sensors in the robot type, it allows the machine to negotiate uneven terrain. In the six legged “Timberjack Walking Machine”, the pilot has limited control of the machine, whereas the on board computer makes the legs function in correct sequence to prevent tipping and to negotiate the complex terrain of the forest. The pilot can steer the machine and use the log cutting and stripping apparatus to prepare raw logs for the lumber industry. Asimo the robot, developed by Honda, is a fully autonomous robot and bipedal walking machine. Another bipedal walking machine, that is piloted, was seen in the second movie of the “Aliens” series. This is a real machine rented to the move set. It's function is primarily to magnify human muscle power for cramped loading and unloading operations in warehouses where heavy objects like engines are handled.
The hydraulic system is the “muscle” of the walking machine. The fluid is delivered through hoses to bi-directional hydraulic rams that activate the legs. Pumps the move the fluid are electronically wired to the computer that decides which pumps operate when and in which direction the fluid flows to extend or flex the particular limbs in the correct sequence. It is equivalent to muscle, but works by expansion rather than contraction as seen in muscle. The rams in the best designs are incorporated into the legs themselves. The feet incorporate shock absorbers and are semi flexible so as to handle a wide variety of terrain and do not as a rule have any hydraulics. They do however, have sensors that operate as a feedback system to the computer that operates the hydraulic legs.
The engine operates the pumps that drives the hydraulics and in the case of the Timberjack, the harvester as well. The engine can be fully electrical, such as found in the “Spider” a solar powered research walking machine based in Vancouver, BC, or it can incorporate a diesel engine to power both pumps via a generator or directly as well as other tools that may be part of the machine.
Mechanical parts are all the legs and joints that are designed to have as much articulation as possible so that the whole machine can operate efficiently in the complex environment. It also consists of all the hydraulic rams that are coupled with the legs, the hoses that deliver or remove hydraulic oil, the complex valves and the pumps.
Vancouver, BC boasts its own 8 legged walking machine
The legs are often custom designed, at least in the beginning, to function for a particular machine. The legs are designed to function in at least two axes; up and down and side to side; for maximum manoeuvrability. The feet are often very simple, rounded pads with shock absorbers and sensors to give the computer feedback. Creating articulated joints like we see in the human hip or shoulders has been a trick to mimic and this is often done with two rotating mechanical joints positioned in 90 degree orientation to give the maximum flexibility. Some machines incorporate springs as shock absorbers, but they are seldom used in the legs themselves.
The controls are often configured through two joysticks for the machines where maximum pilot input is required. Walking machines are not configured like a car, because the two are completely different in function. A walking machine can go where no car can ever be coaxed. When was the last time you parallel parked by moving the car sideways? The walking machine can handle this task easily. Cars cannot negotiate a field of boulders, whereas the walking machine can. A walking machine can navigate through boggy or spongy terrain where a car or truck would get hopelessly mired.
Six legged or two legged, the functions are virtually identical. Only the designs are different. Asimo, the robot is a fully autonomous two legged walking machine. Timberjack is a piloted walking machine designed to do a specific job. Military ones that are likely in existence, are designed for a host of operations.
Other than this, walking machines have been the substance of science fiction. It started with H. G. Wells “War of the Worlds” where Mars seeks to conquer the Earth using machines that have three flexible legs. From there, many variations of walking machines were conceived such as those in Star Wars “The Empire Strikes Back” and the “Terminator” series. They are now a reality and the day is not far off when they will be commonplace.
Asimo performs and is almost human like in action!
Here is a four legged dog like walking machine.
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Developments in robotics are assisting in making an all terrain walking machine as shown in the video attached to the web page.