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Mobile robotics — state of the art review
149
Mobile Robotics
State of the Art Review
T.M. Knasel, Editor-in-Chief Introduction This r e p o r t was u n d e r t a k e n to evaluate the research efforts in m o b i l e r o b o t s on a w o r l d w i d e basis as r e p o r t e d at the S e p t e m b e r 1985 I n t e r n a tional C o n f e r e n c e a n d E x p o s i t i o n s in Japan. This u n i q u e o p p o r t u n i t y p r o v i d e d a basis for evaluation of the key technical points. M y overall impressions are that J a p a n e s e interests have t a k e n a l e a d i n g p o s i t i o n in m a n y aspects of the m o b i l e a u t o m a t i o n . M o s t of the m a j o r J a p a n e s e business g r o u p s have m a d e s u b s t a n t i a l i n v e s t m e n t s in robotics, b u t there are also m a j o r activities in the u s a n d Europe. T h e c a t e g o r y ' m o b i l e r o b o t i c s ' is d e f i n e d for
the p u r p o s e s of this review b y technological parameters. T a b l e 1 illustrates five activity generations, a n d the salient characteristics of the c o m m a n d / c o n trol, mobility, e m p l o y m e n t a n d d a t e of m a t u r i t y for each. W i t h this as a f r a m e w o r k we can discuss the progress o b s e r v e d d u r i n g this trip. This r e p o r t focuses o n the fourth g e n e r a t i o n robots, where m o b i l i t y is the key. This p a s t Sep•t e m b e r in J a p a n c o n s i d e r a b l e progress was evident in the field of m o b i l e robots. T h e J a p a n e s e " h a z a r d o u s d u t y r o b o t s " project, n o w in its seco n d phase, has p r o d u c e d some convincing d e m o n s t r a t i o n s of the p r a c t i c a l i t y of walking, a d v a n c e d hands, vision a n d voice technology. These efforts are s p o n s o r e d b y MITI with the assistance of taxation specially levied on the affected industries.
Table 1. The Five Generations of Robotics Generation
Name
Control
Mobility
Usage
Year of Maturity
One
Pick & place
Fixed stop Limit switches sensors, taught points
None
Material handling, machine tending
1982
Two
Servo
Servo controlled continuous path proportional sensors taught path, with branching
May be track mounted
Spot weld painting, two pass arc welding
1984
Three
Assembly
Precision servo controlled vision, or tactile sensors, or off-line programmed
Track or AOV
Assembly, single pass arc welding, deburring
1988-90
Four
Mobile
Intelligent sensors
Tracked, wheeled, or legged
Construction and maintenance in factory and households
1995-2000
Five
Special features
AI controlled
Walking or thrusters
Military use, or space platforms also in households
2005-2010
North-Holland Robotics 2 (1986) 149-155 0167-8493/86/$3.50 © 1986, Elsevier Science Publishers B.V. (North-Holland)
150
T.M. Knasel / Japanese Momte •oOotics Report
The budget exceeds $100M over 8 years, as one major example.
Data Sources
In preparing this report a number of meetings and associated technical discussions were attended; the principal ones are listed below.
International Conference on Advanced Robotics The ICAR meeting featured discussions of the research and development trends internationally in the fast paced field of robotics and allied areas of automation and artificial intelligence. A total of 400 scientists attended this meeting held just before the ISIR and Robotics Show. The meeting presentations included review of the national policy positions toward robotics research in the USA, several European countries, and some of the more important Asian countries, particularly Japan. Overview presentations of key technological indicators gave the audience a perspective on progress. Sandwiched in between were a number of technical presentations on specific advances by the researchers involved. In total this meeting had 400 attendees, of which 181 were authors of one or more of the 71 papers presented in 10 sessions. The technical topics consisted of general overviews (11 papers), control, programming and sensor integration (29), sensing (11), and locomotion (10). Stressed were the plans for the Japanese JUPITER program on robots for hazardous work, and details on the Wabot-2, a humanoid robot capable of playing an electric organ, sight reading music, and singing. This was one of the hits at the Tsukuba EXPO-85.
Harumi, Tokyo, September 12 to 16, 1985. This meeting featured 91 vendors, and was attended by approximately 20,000 people. The show proved to be the place where many of the large companies were showing complete lines of equipment, as well as technical innovation. Lavish displays of robotic technology were the order of the day.
International Exposition, Tsukuba, Japan, 1985 The TSUKUBA EXPO-85 held from March to mid September 1985 hosted some 20 million visitors at a specially constructed site near the Tsukuba Science City in Ibaraki Prefecture, some 45 miles north of Tokyo. One hundred and thirteen organizations, including most of the top high technology firms in Japan, presented the future high tech view. Most emphasis was on robotics, advanced communications, and large video displays. The party and festival atmosphere was designed to appeal to children, the aim of much of the show was apparently to introduce them to the technology they will have to master in as easy a way as possible. The EXPO was also designed to create markets in the future for labor saving devices such as home robots.
Technical Evaluation
This report consists of an identification of the leading technical issues concerning the application of mobile automation, as seen from the Asian viewpoint. Out of the many topics that were evident, I have chosen those that represent the most important, and significant. In many cases I have put into perspecwze the growth in mobile automation development,, and identified those fastest moving, and those areas that have witnessed breakthroughs. In the following I will discuss: • Automation in the construction industry • Applications of mobile robots in repair and maintenance • Robotic mobility: - Walking robots - Wheeled and tracked locomotion - Robotic hands and arms.
International Symposium on Industrial Robots Held in early September 1985 with 600 attendees. In the 3-day meeting 356 authors presented 125 papers in 23 sessions. The ISIR program was more focused on the practical and applied in its approach, compared to the ICAR meeting which preceded it. Emphasis on direct drive asembly robots, and robots for the construction industry showed that the presenters were able to report new topics that are only just emerging.
Automation in the Construction Industry
International Industrial Robot Exhibition Held at the International Trade Fair Center,
One topical area where Japanese interests are farther advanced than those in the USA or Europe
T.M. Knasel /Japanese Mobile Robotics Report
is the study of the use of robotics in the construction and maintenance industries. This has been a particularly strong area of Japanese involvement for the better part of the past decade. There are strong industrial and government programs, supported by a number of university teams. One presentation of particular note was that of the Kajima Co. concerning their development of a robot for finishing of concrete floors in building construction. Kajima is a large Japanese construction firm that has had responsibilities for such projects as the Seikan tunnel, the world's largest tunnel, industrial plants, and buildings worldwide. I spoke with Mr. N. Tanaka, head of the mechanical engineering section, whose responsibility was to develop automated equipment for construction. So far, their projects have included robots to spray shotcrete, to apply water jet cutting, to install rebar, and to inspect tile walls. At the ISIR meeting Tanaka spoke on the latest robot, aimed at slab finishing. The unit has been in development for three years. The work commenced with a study of hundreds of construction jobs that could be automated, and included an estimate of the difficulty for automation of such a task. Out of this effort Kajima identified the slab finishing robot as needed, effective and well within the present technology. The slab finishing robot had the highest evaluation by the criteria of need and probable development success. In 1984 a prototype unit was constructed and tested. Some of the design criteria were: low weight, so as to not disturb the floor slab, internal navigation so that external markers were not required, accurate control of floor level, and ability to work unattended overnight. The prototype unit tested well, and a second gereration unit is under development. The unit is quite effective as shown in films. An overhead cable provides power, otherwise the unit operates without intervention over a large floor area. About 95% of the floor area can be finished in an unattended manner. The remaining 5% represent the periphery, and area around supporting columns. These have to be finished manually. This is a typical pragmatic Japanese approach in automation. The Japanese Ministry of Construction and the Waseda University have programs to study other ways to use robots in construction and maintenance. Under the Waseda program 11 Japanese companies are cooperating on a study of the use
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of robots in construction of walls made of preformed concrete. The Ministry of Construction is sponsoring further investigation into the uses of robots, and has started one project concerning the automation of bulldozers. Komatsu, the large construction equipment manufacturer, has had a long standing interest in automated factory and construction site equipment. Several years ago they demonstrated a remotely controlled bulldozer. The company is active in industrial automation in the arc welding and punch press handling areas. Of note now is the extension of prior work on sea bed walking robots by Komatsu. In 1983-84 they developed a sea bottom rubble leveling robot that can be used in the breakwater foundation construction task, at a depth of 30 m. The unit uses two space frames of four legs each, and walking is accomplished by shifting from one frame to the other. Tests by the company showed that 3000 s q . m / d a y can be leveled to + / - 5 cm true slope. A 10 m wide rake stroke is achieved. This gives a 40 times productivity improvement over using divers, which Komatsu says is the competing method.
Applications of Mobile Robots in Repair and Maintenance A number of good presentations were made at the meetings on applications for devices that exhibit robotic mobility. The distinction between those projects mentioned above is that here the primary focus is on the system, not on the mobility. Indeed in most cases the mobile platform has already been developed. Such is the case with the work of the Sogo Keibi Hoshou Co. of Tokyo, that has developed a security guard robot. The development team had been associated with the work at the University of Tsukuba on the " Y a m a b i c o " robot, and used this device, not unlike the Hero model in the USA, as the base for their development. Locomotion is by two independently servo steered motor driven wheels, with two casters for stability. Navigation is through ultrasonic sensors, primarily, but bumpers and IR sensors are factored in, too. I saw the Yamabico four years ago and it was able to move about 0.5 m / s e c in a maze travelling exercise. Programming and memory were adequate at that time for simple maze solution to be readily made. The present team did not discuss potential improvements in this area, but chose
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instead to emphasize the control system and sensors that make this unit a security robot. The robot is equipped with twelve ultrasonic transducers for various sectors, with body heat and combustion IR detectors, the latter two on a pan/tilt mechanism to aid in localization. Proximity and contact devices are also provided. It also has a speech synthesis capability so that it can report status. Finally two halon fire extinguishers, recording cameras and flash, and radio communications are provided. The sensors are all tied on a bus structure to the controller. The robot has been recently developed and is undergoing initial tests. The team plans to add vision and improve the software in the next phase of their efforts.
Robotic Mobility The ability of robots to move to work sites is a far reaching capability just now starting to emerge from research. By virtue of the Tsukuba Expo and conference reports, I have been able to summarize the latest situation in two areas, walking machines and freely mobile wheeled or tracked vehicles.
Walking Robots The ability of robots to walk is probably the hardest challenge in the field today. While not yet solved, I saw very important efforts toward successful walking locomotion during the Japan visit. As a beginning to the discussion of legged locomotion I wish to point out that there are degrees of complexity within this topic that should be appreciated initially before discussions of any specific results. The most challenging type of legged locomotion is that of the two anthropomorphic multijointed legs. Like the human, a two legged robot must be able to balance as it raises one leg to stride. The next lower degree of legged operation is four, six or eight legged. Balancing is easier, and the legs themselves are less complex, with fewer pivoting joints, and additionally a rotating hip joint can be added for dexterity. Legged locomotion is much less developed compared to tracked or wheeled efforts, and is still in the early prototype stages. At Tsukuba, Hitachi demonstrated both a two and four legged walking unit, and in the Japanese Theme Pavilion, Waseda University showed two and four legged walking machines in operation.
The demonstrations technically worked, in the sense that the two legged machines traversed a short level course, and the multiple legged devices climb shallow staircases, but the rate is very slow and the off-board computation required is extensive. The efforts in Japan have been longstanding in their interest in human-like legged walking, with knee jointed bipeds. With the advent of parallelogram linked legs in spider-like devices, commercially pioneered by Odetics Corporation in the USA, another wave of efforts has gotten under way in Japan. For example MELWALK-III is a hexapod walking machine with the body center of gravity well under the leg knee joint. Motoda Electronics, working in conjunction with several Japanese universities, has taken a different approach. Motoda, noting that in the factory a special path can be prepared for a walking robot, have created the "Born Floor", a magnetic platform that allows attachment of the feet and makes it possible to study walking without the need to solve the balance problem first. Demonstrations at the Robotics exhibition by the company were in a theatre arrangement. One has to question the practicality of the use of a special floor for walking, since wheeled and tracked vehicles could be more effectively used in that case. As a way to study walking it has merit, however. The experimental walking machine being built at the Ohio State University by professors McGee and Waldron was discussed. The vehicle uses an adaptive suspension to smooth the "ride" of the supervisor operator on-board, thus the name Adaptive Suspension Vehicle (ASV) distinguished this from other walking machines. The device has six parallelogram linkage legs arrayed three on each side of the aligned structure. The vehicle is designed for sustained travel in an unstructured outdoor, and hence uneven environment. The alignment of the structure and the legs makes for a degree of efficiency in straight ahead travel. ASV is over 5 m in length and 2.5 m wide, it weighs about 2700 kg and can carry about one tenth of that as a payload. Hydraulic actuators are used to move the legs. The machine a outfitted with a self contained motor and flywheel for energy storage. Navigation systems include vision and a laser rangefinder. The system was completed as of September of 1985, and will be in a
T.M. Knasel /Japanese Mobile Robotics Report
test program for about one year. The sponsorship of the work is from DARPA. Wheeled and Tracked Locomotion Much good work in wheeled in tracked locomotion is being carried out around the world. I was able to cover some of this in the section on robots for the construction industry. A second application area that is driving the use of mobile robots is maintenance work in nuclear reactors. I have already discussed the Japanese government plans in this area. Here I will discuss the applications research underway. Toshiba is exploiting the multijointed arm work they have underway, by using a 17 DOF arm mounted on a wheeled vehicle for inspection in the turbine areas on nuclear reactors. Dubbed the Turbine Building Inspection Robot (TBIS), the unit is used in nuclear facilities. Because the radiation levels are high, most of the electronics are at a remote station, and a cable is payed out to the vehicle as it traverses the building. The basic idea is to use the long flexible arm (almost 2.5 m long) to get into the nooks and crannies of the plant while it is in operation and to be able to check on conditions. Although teleoperated in most cases now, Toshiba presented the results of a study of the use of collision avoidance software that could make full automatic control a reality. Another participant in the nuclear program is Mitsubishi Heavy Industries. Their contribution is a tracked and legged vehicle with some extraordinary capability due to the special design. The application is for the inspection of the inside of the containment vessel of a nuclear reactor. Fairly small in overall size, the robot is about 0.5 by 0.5 m in base size, and 1.2 m high, and weighs about 400 kg. The unit is called " c / v ROBOT", for containment vessel robot, and is fully shielded and protected against the high radiation environment of the insides of a nuclear reactor. In contrast to the Toshiba unit, the MHI (Mitsubishi Heavy Industries) robot carries both a camera and a manipulator arm. Due to the unique locomotion scheme, the robot can traverse flat floors using the two drive wheels for propulsion, tucking in the legs, and putting the wheels at the end of the legs in idle. For stair climbing, the legs are used, and for intermediate obstacles, a combination of both is used. An extensive control panel for vehicle guidance and teleoperation of the arm
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has been provided. Adjustable force feedback on the arm control is another feature. MHI has been working on the project for five years. In a related activity Mitsubishi Electric has extended the MHI concept a bit farther in their Multifunctional Robotic Vehicle (MRV-I). This device uses four tracked segments as either legs, or tracks as the situation dictates. Hitachi is the third major company participating in the first phase work sponsored by MITI on robots for dangerous environments. In their case, they have a concept for locomotion that is tracked, but with a triangular path for the track, their robot can climb obstacles, much as a battle tank does. However, the Autonomous Mobile Robot has an extra trick up its sleeve. An arm on either side has an idler wheel over which the track rolls. The arm can be positioned in front and at a forward incline to allow stair climbing to commence. As the stairs are mounted, the arm can swing back to boost the traction of the rear of the robot. The unit has a camera, 6 DOF arm with force feedback' to the operator, and uses carbon fiber reinforced plastics in the body to reduce weight. A road speed of 2 k m / h r is reported for the unit which weighs 150 kg, and can carry a payload of an equal amount. Wireless data transmission has been a special area of Hitachi involvement. They have developed a spread spectrum transmission system that allows the high bandwidth signals used to control the robot to be received despite the interferences of the reactor e n v i r o n m e n t . . Finally, some results of the us program on the Autonomous Land Vehicle (ALV) were presented in an overview of robot mobility. The ALV project is sponsored by DARPA, and aimed at solving the navigation problem for robot guidance in an unstructured environment. In this aspect the effort, going on at Martin Marietta Denver Aerospace, with the assistance of many subcontractors is ahead of the work in Japan. The ALV is a large vehicle, the size of a delivery van. It needs to be this large to accommodate the extensive on-board computational capability for the navigational task. So far the unit has traversed a 1.7 km road by using the center stripe of the road as a visual guide, and achieved a 2 k m / h r rare. More tests are planned, as the program has only been underway for about one year. The Atomic Energy Agency of Belgium re-
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ported on a remote operational vehicle for nuclear reactor use. Their idea is to use three sets of tracks, a main set for traction and two auxiliary pairs that can be inclined to mount obstacles. Two teleoperated 6 DOE arms are carried on-board, and each arm has additional freedom in gripping action. Each arm can lift 100 kg and have a work volume of 4 cubic meters. The robot carries two cameras, as well as a battery power supply. Telemetry is radioed to the control station where an operator can judge the situation through several on-board sensors. The robot has just been completed and is now undergoing tests in an operational reactor. Robotic Hands and Arms One of the highpoints of the meeting in Japan was the chance to review so much unique and excellent effort that is being devoted to the development of robotic hands and arms. One is at a loss where to start, but the tour-de-force efforts at Waseda University in developing the Wabot-II, or Wasebot deserve first mention. This robot i~ an organ playing robot, but that description is inadequate. Wabot-II is a 50 DOE robotic system with four five-fingered limbs, that under computer control can sight-read music, and play a manual keyboard of an electric organ, and can accompany a singer as well. The vision system to read the notes, and the voice recognition and speech synthesis to accomplish these feats are fairly complex but understandable state-of-the-art accomplishments. The hands and limbs, however, are a clear advance, especially over Western developments. To put the accomplishment in perspective one has to recognize that hand research has been under way for over ten years in Japan. Five years ago, a robot was built that could use carpenter tools, and a hand was developed with three fingers that could twirl a stick. The Wabot-II is a direct derivative of these efforts, but with some impressive advances, particularly in the area of software control. The fingers are multijointed cable driven, a now standard technique. The speed of control is at a rate of 15 key strokes per second, faster than the best pianist by about two times. The performance is obtained through the use of a hierarchical network of some 80 microprocessors. A series of technical presentations by the 50 member
Waseda team that worked 3½ years on the project, and the performance of the robot at the Japanese theme pavilion at the Tsukuba Expo-85 made this the most recognised robot since c3Po. Also at Tsukuba, and illustrating the dexterity capacity of robotics were the two coordinated top spinning robots at the Toshiba pavilion, and the two coordinated ice carving robots at the Hitachi area. However, in both of the latter cases the units were standard industrial models, but with exceptional software control. The Matsushita display of a portrait drawing robot, while again an industrial model illustrated the dexterity and intelligence possible through computer control. I was able to estimate from data gathered at the meetings that about us $1M in research is going into flexible h a n d / a r m activities in Japan. Probably about half this much is being expended in the USA, and somewhat less in Europe. Buoyed by the success of the recent efforts, Japan is upping its budgets for h a n d / a r m development by a factor of 10, and aiming the development in the maintenance and hazardous task area. Professor Bernard Ross of Stanford University gave an excellent retrospective on h a n d / a r m research in the USA. At the University of Utah, Professor Steve Jacobson has a three fingered, one thumb hand in development as a prosthetic device. Each digit has 4 DOF and is cable driven. Ken Salisbury, formerly of Stanford, now at the MIX-AI lab, has been working on a two finger, one thumb hand, with a total of 8 DOF, three in each finger and two in the thumb. This unit is also cable driven, and uses force sensing in addition. Also at Stanford research in the control of flexible arms is under the direction of Professor Cannon. In the commercial arena, Toshiba, working under government sponsorship to develop an arm for nuclear power plant maintenance, had developed a multi-degree of freedom arm, using a 30 degree swivel joint. Their arm is 2.5 m in length, can carry a 30 kg load and position to 5 m m accuracy, and 0.5 m m repeatability. I had the chance to review at the robot exhibition the introduction by Bridgestone of their " r u b b e r muscle" drive robot. Through the clever use of two opposing rubber tubes, and the control of air pressure, a controlled two way motion can be obtained. The overall idea is based on the human muscle. This is then built up into a robot arm by the use of multiple joints. The net effect is
T.M. Knasel / Japanese Mobile Robotics Report
to have a nearly unity strength to weight ratio, with acceptable position accuracy. A company official briefed me on the Bridgestone work. The unit shown at the exposition was being seen for the first time. Several configurations were displayed including a SCARA configuration. The company intends to sell kits to firms that allow one to experiment with the muscle cells. The robots shown were early prototypes and the production units have not yet been priced. Speed and reliability appear to be good. Bridgestone claims that a one million stroke life is possible for the basic muscle units. A particularly good example of a practical manipulator arm is that of the 9 degree of freedom (DOF) arm constructed by Professor H. Yoshikawa and his team at the University of Tokyo. The manipulator is being developed to be mounted on a mobile robot called "A MOOTY", which is a device intended for nuclear reactor maintenance work. The University of Tokyo work is being assisted by government grants, and the Toshiba Corp. nuclear group. The arm is designed to be metamorphic in structure to allow flexibility in reaching around obstacles in maintenance jobs. Design considerations include light weight, high precision, large working envelope, and easy to control. The Tokyo University group made an extensive study of the possible designs using rotary, pivoting, and sliding joints, and have come up with a practical design that has adequate performance and can be controlled easily. The actuators are dc servo motors, and the arm structural material is made of carbon fiber reinforced plastic. Mitsubishi Heavy Industries (Mm) have been experimenting with a three fingered hand, using a
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dexterous " t h u m b " with 3 or 4 degrees of freedom, including base rotation, accompanied by two opposing "fingers" each with 2 DOF pivot joints. They have studied with two models, one with three thumb joints, the other with two, a series of tasks typical of industrial jobs. A master slave control is used in the tests, and to simplify the job the two fingers are forced to move together equal amounts. Despite the limitations of the set-up the research team reported excellent results in a series of everyday jobs, such as the picking up of a bolt and attaching it, and grasping objects of various shapes. They found that the finger tips should be round in cross section and covered with a rubber coating to provide an anti-slip capability. Generally fewer degrees of freedom were preferable for control, thus the model with one less thumb joint worked better overall. The thumb rotation was not judged as useful as the other pivot joints.
Conclusion The happy coincidence of so many major robotics events in Japan in September 1985, allowed a unique opportunity to evaluate progress in robotic mobility functions. The technological developments are no longer curiosities for the laboratory. Practical tasks are now possible in construction and maintenance activities that are best done by mobile robots. The worldwide concern for safety of maintenance of nuclear power plants, underwater construction and other tasks nearly impossible to do any other way will now utilize the painstaking research efforts described here and promote wider spread of interest and progress in this important area of robotics.
Mobile Robotics
State of the Art Review
T.M. Knasel, Editor-in-Chief Introduction This r e p o r t was u n d e r t a k e n to evaluate the research efforts in m o b i l e r o b o t s on a w o r l d w i d e basis as r e p o r t e d at the S e p t e m b e r 1985 I n t e r n a tional C o n f e r e n c e a n d E x p o s i t i o n s in Japan. This u n i q u e o p p o r t u n i t y p r o v i d e d a basis for evaluation of the key technical points. M y overall impressions are that J a p a n e s e interests have t a k e n a l e a d i n g p o s i t i o n in m a n y aspects of the m o b i l e a u t o m a t i o n . M o s t of the m a j o r J a p a n e s e business g r o u p s have m a d e s u b s t a n t i a l i n v e s t m e n t s in robotics, b u t there are also m a j o r activities in the u s a n d Europe. T h e c a t e g o r y ' m o b i l e r o b o t i c s ' is d e f i n e d for
the p u r p o s e s of this review b y technological parameters. T a b l e 1 illustrates five activity generations, a n d the salient characteristics of the c o m m a n d / c o n trol, mobility, e m p l o y m e n t a n d d a t e of m a t u r i t y for each. W i t h this as a f r a m e w o r k we can discuss the progress o b s e r v e d d u r i n g this trip. This r e p o r t focuses o n the fourth g e n e r a t i o n robots, where m o b i l i t y is the key. This p a s t Sep•t e m b e r in J a p a n c o n s i d e r a b l e progress was evident in the field of m o b i l e robots. T h e J a p a n e s e " h a z a r d o u s d u t y r o b o t s " project, n o w in its seco n d phase, has p r o d u c e d some convincing d e m o n s t r a t i o n s of the p r a c t i c a l i t y of walking, a d v a n c e d hands, vision a n d voice technology. These efforts are s p o n s o r e d b y MITI with the assistance of taxation specially levied on the affected industries.
Table 1. The Five Generations of Robotics Generation
Name
Control
Mobility
Usage
Year of Maturity
One
Pick & place
Fixed stop Limit switches sensors, taught points
None
Material handling, machine tending
1982
Two
Servo
Servo controlled continuous path proportional sensors taught path, with branching
May be track mounted
Spot weld painting, two pass arc welding
1984
Three
Assembly
Precision servo controlled vision, or tactile sensors, or off-line programmed
Track or AOV
Assembly, single pass arc welding, deburring
1988-90
Four
Mobile
Intelligent sensors
Tracked, wheeled, or legged
Construction and maintenance in factory and households
1995-2000
Five
Special features
AI controlled
Walking or thrusters
Military use, or space platforms also in households
2005-2010
North-Holland Robotics 2 (1986) 149-155 0167-8493/86/$3.50 © 1986, Elsevier Science Publishers B.V. (North-Holland)
150
T.M. Knasel / Japanese Momte •oOotics Report
The budget exceeds $100M over 8 years, as one major example.
Data Sources
In preparing this report a number of meetings and associated technical discussions were attended; the principal ones are listed below.
International Conference on Advanced Robotics The ICAR meeting featured discussions of the research and development trends internationally in the fast paced field of robotics and allied areas of automation and artificial intelligence. A total of 400 scientists attended this meeting held just before the ISIR and Robotics Show. The meeting presentations included review of the national policy positions toward robotics research in the USA, several European countries, and some of the more important Asian countries, particularly Japan. Overview presentations of key technological indicators gave the audience a perspective on progress. Sandwiched in between were a number of technical presentations on specific advances by the researchers involved. In total this meeting had 400 attendees, of which 181 were authors of one or more of the 71 papers presented in 10 sessions. The technical topics consisted of general overviews (11 papers), control, programming and sensor integration (29), sensing (11), and locomotion (10). Stressed were the plans for the Japanese JUPITER program on robots for hazardous work, and details on the Wabot-2, a humanoid robot capable of playing an electric organ, sight reading music, and singing. This was one of the hits at the Tsukuba EXPO-85.
Harumi, Tokyo, September 12 to 16, 1985. This meeting featured 91 vendors, and was attended by approximately 20,000 people. The show proved to be the place where many of the large companies were showing complete lines of equipment, as well as technical innovation. Lavish displays of robotic technology were the order of the day.
International Exposition, Tsukuba, Japan, 1985 The TSUKUBA EXPO-85 held from March to mid September 1985 hosted some 20 million visitors at a specially constructed site near the Tsukuba Science City in Ibaraki Prefecture, some 45 miles north of Tokyo. One hundred and thirteen organizations, including most of the top high technology firms in Japan, presented the future high tech view. Most emphasis was on robotics, advanced communications, and large video displays. The party and festival atmosphere was designed to appeal to children, the aim of much of the show was apparently to introduce them to the technology they will have to master in as easy a way as possible. The EXPO was also designed to create markets in the future for labor saving devices such as home robots.
Technical Evaluation
This report consists of an identification of the leading technical issues concerning the application of mobile automation, as seen from the Asian viewpoint. Out of the many topics that were evident, I have chosen those that represent the most important, and significant. In many cases I have put into perspecwze the growth in mobile automation development,, and identified those fastest moving, and those areas that have witnessed breakthroughs. In the following I will discuss: • Automation in the construction industry • Applications of mobile robots in repair and maintenance • Robotic mobility: - Walking robots - Wheeled and tracked locomotion - Robotic hands and arms.
International Symposium on Industrial Robots Held in early September 1985 with 600 attendees. In the 3-day meeting 356 authors presented 125 papers in 23 sessions. The ISIR program was more focused on the practical and applied in its approach, compared to the ICAR meeting which preceded it. Emphasis on direct drive asembly robots, and robots for the construction industry showed that the presenters were able to report new topics that are only just emerging.
Automation in the Construction Industry
International Industrial Robot Exhibition Held at the International Trade Fair Center,
One topical area where Japanese interests are farther advanced than those in the USA or Europe
T.M. Knasel /Japanese Mobile Robotics Report
is the study of the use of robotics in the construction and maintenance industries. This has been a particularly strong area of Japanese involvement for the better part of the past decade. There are strong industrial and government programs, supported by a number of university teams. One presentation of particular note was that of the Kajima Co. concerning their development of a robot for finishing of concrete floors in building construction. Kajima is a large Japanese construction firm that has had responsibilities for such projects as the Seikan tunnel, the world's largest tunnel, industrial plants, and buildings worldwide. I spoke with Mr. N. Tanaka, head of the mechanical engineering section, whose responsibility was to develop automated equipment for construction. So far, their projects have included robots to spray shotcrete, to apply water jet cutting, to install rebar, and to inspect tile walls. At the ISIR meeting Tanaka spoke on the latest robot, aimed at slab finishing. The unit has been in development for three years. The work commenced with a study of hundreds of construction jobs that could be automated, and included an estimate of the difficulty for automation of such a task. Out of this effort Kajima identified the slab finishing robot as needed, effective and well within the present technology. The slab finishing robot had the highest evaluation by the criteria of need and probable development success. In 1984 a prototype unit was constructed and tested. Some of the design criteria were: low weight, so as to not disturb the floor slab, internal navigation so that external markers were not required, accurate control of floor level, and ability to work unattended overnight. The prototype unit tested well, and a second gereration unit is under development. The unit is quite effective as shown in films. An overhead cable provides power, otherwise the unit operates without intervention over a large floor area. About 95% of the floor area can be finished in an unattended manner. The remaining 5% represent the periphery, and area around supporting columns. These have to be finished manually. This is a typical pragmatic Japanese approach in automation. The Japanese Ministry of Construction and the Waseda University have programs to study other ways to use robots in construction and maintenance. Under the Waseda program 11 Japanese companies are cooperating on a study of the use
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of robots in construction of walls made of preformed concrete. The Ministry of Construction is sponsoring further investigation into the uses of robots, and has started one project concerning the automation of bulldozers. Komatsu, the large construction equipment manufacturer, has had a long standing interest in automated factory and construction site equipment. Several years ago they demonstrated a remotely controlled bulldozer. The company is active in industrial automation in the arc welding and punch press handling areas. Of note now is the extension of prior work on sea bed walking robots by Komatsu. In 1983-84 they developed a sea bottom rubble leveling robot that can be used in the breakwater foundation construction task, at a depth of 30 m. The unit uses two space frames of four legs each, and walking is accomplished by shifting from one frame to the other. Tests by the company showed that 3000 s q . m / d a y can be leveled to + / - 5 cm true slope. A 10 m wide rake stroke is achieved. This gives a 40 times productivity improvement over using divers, which Komatsu says is the competing method.
Applications of Mobile Robots in Repair and Maintenance A number of good presentations were made at the meetings on applications for devices that exhibit robotic mobility. The distinction between those projects mentioned above is that here the primary focus is on the system, not on the mobility. Indeed in most cases the mobile platform has already been developed. Such is the case with the work of the Sogo Keibi Hoshou Co. of Tokyo, that has developed a security guard robot. The development team had been associated with the work at the University of Tsukuba on the " Y a m a b i c o " robot, and used this device, not unlike the Hero model in the USA, as the base for their development. Locomotion is by two independently servo steered motor driven wheels, with two casters for stability. Navigation is through ultrasonic sensors, primarily, but bumpers and IR sensors are factored in, too. I saw the Yamabico four years ago and it was able to move about 0.5 m / s e c in a maze travelling exercise. Programming and memory were adequate at that time for simple maze solution to be readily made. The present team did not discuss potential improvements in this area, but chose
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instead to emphasize the control system and sensors that make this unit a security robot. The robot is equipped with twelve ultrasonic transducers for various sectors, with body heat and combustion IR detectors, the latter two on a pan/tilt mechanism to aid in localization. Proximity and contact devices are also provided. It also has a speech synthesis capability so that it can report status. Finally two halon fire extinguishers, recording cameras and flash, and radio communications are provided. The sensors are all tied on a bus structure to the controller. The robot has been recently developed and is undergoing initial tests. The team plans to add vision and improve the software in the next phase of their efforts.
Robotic Mobility The ability of robots to move to work sites is a far reaching capability just now starting to emerge from research. By virtue of the Tsukuba Expo and conference reports, I have been able to summarize the latest situation in two areas, walking machines and freely mobile wheeled or tracked vehicles.
Walking Robots The ability of robots to walk is probably the hardest challenge in the field today. While not yet solved, I saw very important efforts toward successful walking locomotion during the Japan visit. As a beginning to the discussion of legged locomotion I wish to point out that there are degrees of complexity within this topic that should be appreciated initially before discussions of any specific results. The most challenging type of legged locomotion is that of the two anthropomorphic multijointed legs. Like the human, a two legged robot must be able to balance as it raises one leg to stride. The next lower degree of legged operation is four, six or eight legged. Balancing is easier, and the legs themselves are less complex, with fewer pivoting joints, and additionally a rotating hip joint can be added for dexterity. Legged locomotion is much less developed compared to tracked or wheeled efforts, and is still in the early prototype stages. At Tsukuba, Hitachi demonstrated both a two and four legged walking unit, and in the Japanese Theme Pavilion, Waseda University showed two and four legged walking machines in operation.
The demonstrations technically worked, in the sense that the two legged machines traversed a short level course, and the multiple legged devices climb shallow staircases, but the rate is very slow and the off-board computation required is extensive. The efforts in Japan have been longstanding in their interest in human-like legged walking, with knee jointed bipeds. With the advent of parallelogram linked legs in spider-like devices, commercially pioneered by Odetics Corporation in the USA, another wave of efforts has gotten under way in Japan. For example MELWALK-III is a hexapod walking machine with the body center of gravity well under the leg knee joint. Motoda Electronics, working in conjunction with several Japanese universities, has taken a different approach. Motoda, noting that in the factory a special path can be prepared for a walking robot, have created the "Born Floor", a magnetic platform that allows attachment of the feet and makes it possible to study walking without the need to solve the balance problem first. Demonstrations at the Robotics exhibition by the company were in a theatre arrangement. One has to question the practicality of the use of a special floor for walking, since wheeled and tracked vehicles could be more effectively used in that case. As a way to study walking it has merit, however. The experimental walking machine being built at the Ohio State University by professors McGee and Waldron was discussed. The vehicle uses an adaptive suspension to smooth the "ride" of the supervisor operator on-board, thus the name Adaptive Suspension Vehicle (ASV) distinguished this from other walking machines. The device has six parallelogram linkage legs arrayed three on each side of the aligned structure. The vehicle is designed for sustained travel in an unstructured outdoor, and hence uneven environment. The alignment of the structure and the legs makes for a degree of efficiency in straight ahead travel. ASV is over 5 m in length and 2.5 m wide, it weighs about 2700 kg and can carry about one tenth of that as a payload. Hydraulic actuators are used to move the legs. The machine a outfitted with a self contained motor and flywheel for energy storage. Navigation systems include vision and a laser rangefinder. The system was completed as of September of 1985, and will be in a
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test program for about one year. The sponsorship of the work is from DARPA. Wheeled and Tracked Locomotion Much good work in wheeled in tracked locomotion is being carried out around the world. I was able to cover some of this in the section on robots for the construction industry. A second application area that is driving the use of mobile robots is maintenance work in nuclear reactors. I have already discussed the Japanese government plans in this area. Here I will discuss the applications research underway. Toshiba is exploiting the multijointed arm work they have underway, by using a 17 DOF arm mounted on a wheeled vehicle for inspection in the turbine areas on nuclear reactors. Dubbed the Turbine Building Inspection Robot (TBIS), the unit is used in nuclear facilities. Because the radiation levels are high, most of the electronics are at a remote station, and a cable is payed out to the vehicle as it traverses the building. The basic idea is to use the long flexible arm (almost 2.5 m long) to get into the nooks and crannies of the plant while it is in operation and to be able to check on conditions. Although teleoperated in most cases now, Toshiba presented the results of a study of the use of collision avoidance software that could make full automatic control a reality. Another participant in the nuclear program is Mitsubishi Heavy Industries. Their contribution is a tracked and legged vehicle with some extraordinary capability due to the special design. The application is for the inspection of the inside of the containment vessel of a nuclear reactor. Fairly small in overall size, the robot is about 0.5 by 0.5 m in base size, and 1.2 m high, and weighs about 400 kg. The unit is called " c / v ROBOT", for containment vessel robot, and is fully shielded and protected against the high radiation environment of the insides of a nuclear reactor. In contrast to the Toshiba unit, the MHI (Mitsubishi Heavy Industries) robot carries both a camera and a manipulator arm. Due to the unique locomotion scheme, the robot can traverse flat floors using the two drive wheels for propulsion, tucking in the legs, and putting the wheels at the end of the legs in idle. For stair climbing, the legs are used, and for intermediate obstacles, a combination of both is used. An extensive control panel for vehicle guidance and teleoperation of the arm
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has been provided. Adjustable force feedback on the arm control is another feature. MHI has been working on the project for five years. In a related activity Mitsubishi Electric has extended the MHI concept a bit farther in their Multifunctional Robotic Vehicle (MRV-I). This device uses four tracked segments as either legs, or tracks as the situation dictates. Hitachi is the third major company participating in the first phase work sponsored by MITI on robots for dangerous environments. In their case, they have a concept for locomotion that is tracked, but with a triangular path for the track, their robot can climb obstacles, much as a battle tank does. However, the Autonomous Mobile Robot has an extra trick up its sleeve. An arm on either side has an idler wheel over which the track rolls. The arm can be positioned in front and at a forward incline to allow stair climbing to commence. As the stairs are mounted, the arm can swing back to boost the traction of the rear of the robot. The unit has a camera, 6 DOF arm with force feedback' to the operator, and uses carbon fiber reinforced plastics in the body to reduce weight. A road speed of 2 k m / h r is reported for the unit which weighs 150 kg, and can carry a payload of an equal amount. Wireless data transmission has been a special area of Hitachi involvement. They have developed a spread spectrum transmission system that allows the high bandwidth signals used to control the robot to be received despite the interferences of the reactor e n v i r o n m e n t . . Finally, some results of the us program on the Autonomous Land Vehicle (ALV) were presented in an overview of robot mobility. The ALV project is sponsored by DARPA, and aimed at solving the navigation problem for robot guidance in an unstructured environment. In this aspect the effort, going on at Martin Marietta Denver Aerospace, with the assistance of many subcontractors is ahead of the work in Japan. The ALV is a large vehicle, the size of a delivery van. It needs to be this large to accommodate the extensive on-board computational capability for the navigational task. So far the unit has traversed a 1.7 km road by using the center stripe of the road as a visual guide, and achieved a 2 k m / h r rare. More tests are planned, as the program has only been underway for about one year. The Atomic Energy Agency of Belgium re-
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ported on a remote operational vehicle for nuclear reactor use. Their idea is to use three sets of tracks, a main set for traction and two auxiliary pairs that can be inclined to mount obstacles. Two teleoperated 6 DOE arms are carried on-board, and each arm has additional freedom in gripping action. Each arm can lift 100 kg and have a work volume of 4 cubic meters. The robot carries two cameras, as well as a battery power supply. Telemetry is radioed to the control station where an operator can judge the situation through several on-board sensors. The robot has just been completed and is now undergoing tests in an operational reactor. Robotic Hands and Arms One of the highpoints of the meeting in Japan was the chance to review so much unique and excellent effort that is being devoted to the development of robotic hands and arms. One is at a loss where to start, but the tour-de-force efforts at Waseda University in developing the Wabot-II, or Wasebot deserve first mention. This robot i~ an organ playing robot, but that description is inadequate. Wabot-II is a 50 DOE robotic system with four five-fingered limbs, that under computer control can sight-read music, and play a manual keyboard of an electric organ, and can accompany a singer as well. The vision system to read the notes, and the voice recognition and speech synthesis to accomplish these feats are fairly complex but understandable state-of-the-art accomplishments. The hands and limbs, however, are a clear advance, especially over Western developments. To put the accomplishment in perspective one has to recognize that hand research has been under way for over ten years in Japan. Five years ago, a robot was built that could use carpenter tools, and a hand was developed with three fingers that could twirl a stick. The Wabot-II is a direct derivative of these efforts, but with some impressive advances, particularly in the area of software control. The fingers are multijointed cable driven, a now standard technique. The speed of control is at a rate of 15 key strokes per second, faster than the best pianist by about two times. The performance is obtained through the use of a hierarchical network of some 80 microprocessors. A series of technical presentations by the 50 member
Waseda team that worked 3½ years on the project, and the performance of the robot at the Japanese theme pavilion at the Tsukuba Expo-85 made this the most recognised robot since c3Po. Also at Tsukuba, and illustrating the dexterity capacity of robotics were the two coordinated top spinning robots at the Toshiba pavilion, and the two coordinated ice carving robots at the Hitachi area. However, in both of the latter cases the units were standard industrial models, but with exceptional software control. The Matsushita display of a portrait drawing robot, while again an industrial model illustrated the dexterity and intelligence possible through computer control. I was able to estimate from data gathered at the meetings that about us $1M in research is going into flexible h a n d / a r m activities in Japan. Probably about half this much is being expended in the USA, and somewhat less in Europe. Buoyed by the success of the recent efforts, Japan is upping its budgets for h a n d / a r m development by a factor of 10, and aiming the development in the maintenance and hazardous task area. Professor Bernard Ross of Stanford University gave an excellent retrospective on h a n d / a r m research in the USA. At the University of Utah, Professor Steve Jacobson has a three fingered, one thumb hand in development as a prosthetic device. Each digit has 4 DOF and is cable driven. Ken Salisbury, formerly of Stanford, now at the MIX-AI lab, has been working on a two finger, one thumb hand, with a total of 8 DOF, three in each finger and two in the thumb. This unit is also cable driven, and uses force sensing in addition. Also at Stanford research in the control of flexible arms is under the direction of Professor Cannon. In the commercial arena, Toshiba, working under government sponsorship to develop an arm for nuclear power plant maintenance, had developed a multi-degree of freedom arm, using a 30 degree swivel joint. Their arm is 2.5 m in length, can carry a 30 kg load and position to 5 m m accuracy, and 0.5 m m repeatability. I had the chance to review at the robot exhibition the introduction by Bridgestone of their " r u b b e r muscle" drive robot. Through the clever use of two opposing rubber tubes, and the control of air pressure, a controlled two way motion can be obtained. The overall idea is based on the human muscle. This is then built up into a robot arm by the use of multiple joints. The net effect is
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to have a nearly unity strength to weight ratio, with acceptable position accuracy. A company official briefed me on the Bridgestone work. The unit shown at the exposition was being seen for the first time. Several configurations were displayed including a SCARA configuration. The company intends to sell kits to firms that allow one to experiment with the muscle cells. The robots shown were early prototypes and the production units have not yet been priced. Speed and reliability appear to be good. Bridgestone claims that a one million stroke life is possible for the basic muscle units. A particularly good example of a practical manipulator arm is that of the 9 degree of freedom (DOF) arm constructed by Professor H. Yoshikawa and his team at the University of Tokyo. The manipulator is being developed to be mounted on a mobile robot called "A MOOTY", which is a device intended for nuclear reactor maintenance work. The University of Tokyo work is being assisted by government grants, and the Toshiba Corp. nuclear group. The arm is designed to be metamorphic in structure to allow flexibility in reaching around obstacles in maintenance jobs. Design considerations include light weight, high precision, large working envelope, and easy to control. The Tokyo University group made an extensive study of the possible designs using rotary, pivoting, and sliding joints, and have come up with a practical design that has adequate performance and can be controlled easily. The actuators are dc servo motors, and the arm structural material is made of carbon fiber reinforced plastic. Mitsubishi Heavy Industries (Mm) have been experimenting with a three fingered hand, using a
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dexterous " t h u m b " with 3 or 4 degrees of freedom, including base rotation, accompanied by two opposing "fingers" each with 2 DOF pivot joints. They have studied with two models, one with three thumb joints, the other with two, a series of tasks typical of industrial jobs. A master slave control is used in the tests, and to simplify the job the two fingers are forced to move together equal amounts. Despite the limitations of the set-up the research team reported excellent results in a series of everyday jobs, such as the picking up of a bolt and attaching it, and grasping objects of various shapes. They found that the finger tips should be round in cross section and covered with a rubber coating to provide an anti-slip capability. Generally fewer degrees of freedom were preferable for control, thus the model with one less thumb joint worked better overall. The thumb rotation was not judged as useful as the other pivot joints.
Conclusion The happy coincidence of so many major robotics events in Japan in September 1985, allowed a unique opportunity to evaluate progress in robotic mobility functions. The technological developments are no longer curiosities for the laboratory. Practical tasks are now possible in construction and maintenance activities that are best done by mobile robots. The worldwide concern for safety of maintenance of nuclear power plants, underwater construction and other tasks nearly impossible to do any other way will now utilize the painstaking research efforts described here and promote wider spread of interest and progress in this important area of robotics.