Real-Time Control of Walking

I wonder whether Karel Capek imagined in 1923 that by his use of the Czech word for forced labor, rohota, to name the android creations of Mr. Rossum he was naming an important technology of his future. Perhaps it wasn't Capek's work directly, but rather its influence on Lang's movie Metropolis in 1926 that introduced the term to the popular consciousness. In the public mind ever since a robot has been a me­ chanical humanoid, tireless and somewhat sinister. In the research community the field of robotics has recently reached large size and respectability, but without answering the question, "What is robotics?" or perhaps, "What is a robot?" There is no real consensus for a precise definition of robotics. I suppose that Capekian mechanical men, if one could build them, are robots, but after that there is little agreement. Rather than try to enumerate all of the things that are and are not robots, I will try to characterize the kinds of features that make a system a robot. A candidate definition of a robot is a system intended to achieve mechanical action, with sensory feedback from the world to guide the actions and a sophisticated con­ trol system connecting the sensing and the actions.

Contenu

1.0 Introduction.- One - Machine and animal walking.- 2.0 Animal walking.- 2.1 Locality of control.- 2.1.1 The insect nervous system.- 2.1.2 Insect experiments.- 2.1.3 The spinal cat.- 2.1.4 Reflexes versus patterns.- 2.2 Rear-to-front waves.- 2.3 Why insect gaits are not discrete.- 2.4 Summary.- 3.0 Other walking work.- 3.1 Static stability.- 3.2 Dynamic stability.- 3.3 Summary.- 4.0 SSA walking machine.- 4.1 Mechanical overview.- 4.2 Valve settings.- 4.2.1 Hip control.- 4.2.2 Knee control.- 4.2.3 Valve switching time.- 4.3 Control computers.- 4.4 Hydraulic system.- 4.4.1 Pumps.- 4.4.2 Cylinders.- 4.4.3 Valves.- 4.5 Summary.- 5.0 Walking program.- 5.1 Responsibilities of a walking program.- 5.2 Inhibition and excitation.- 5.3 Walking program structure.- 5.4 Row.- 5.4.1 Load.- 5.4.2 Recover.- 5.5 Service processes.- 5.5.1 Sensors.- 5.5.2 Trouble.- 5.5.3 Compensator monitor.- 5.5.4 Gather.- Two - Programming for robotics and control.- 6.0 Inadequacies of existing control structures.- 6.1 Concurrency.- 6.1.1 Time slicing.- 6.1.2 Algorithmic languages.- 6.1.3 Production systems.- 6.1.4 Concurrent programming languages.- 6.2 Nondeterminacy.- 6.2.1 Concurrent programming languages revisited.- 6.2.2 Guarded commands.- 6.3 The control of temporal behavior.- 6.3.1 Wait for event.- 6.3.2 Complete task before event.- 6.3.3 The nature of loops.- 6.4 Real-time performance.- 6.4.1 Pluribus strips.- 6.4.2 TOMAL.- 6.5 Summary.- 7.0 OWL language.- 7.1 OWL processes.- 7.2 Sequences.- 7.2.1 Asserting done and alert.- 7.2.2 When and bothwhen.- 7.3 Concurrences.- 7.3.1 Handling of alert.- 7.3.2 Concurrent while.- 7.3.3 Synchronization and mutual exclusion.- 7.4 Named processes.- 7.4.1 Scope and parameter passing.- 7.5 Data.- 7.5.1 Datatypes.- 7.5.2 Declarations.- 7.6 Discussion.- 7.6.1 Sequences and loops.- 7.6.2 Concurrence and alternation.- 7.6.3 Distributed implementation.- 7.7 OWL compiler and runtime system.- 7.7.1 Compiler.- 7.7.2 Runtime system.- 7.8 Performance.- 7.9 OWL syntax.- 7.9.1 Walking machine primitives in OWL.- Three - Results and conclusions.- 8.0 Experimental results.- 8.1 Local control.- 8.1.1 Walking.- 8.1.2 Five legged walking.- 8.2 Inhibition.- 8.3 Excitation.- 8.4 Comparison with another program.- 8.5 Summary.- 9.0 Discussion and conclusions.- 9.1 Distributed control.- 9.2 Scaling constraints on walking strategies.- 9.2.1 Why small things cannot balance.- 9.2.2 Why small animals do not have to balance.- 9.2.3 Prognosis for walking machines.- 9.3 Natural motions.- 9.4 Conclusions.- 9.5 Programming: real-time and robotic systems.- 9.6 Directions for future research.- A.O Walking program code.- A.1 Overview.- A.2 Walk.owl.- A.3 Load5.owl.- A.4 Drive7.owl.- A.5 Unload3.owl.- A.6 Recover6.owl.- A.7 Waveinit.owl.- A.8 Sensors.owl.- A.9 Data.owl.- A.10 Trouble.owl.- A.11 Comps.owl.- B.0 Data.- B.1 Description of data figures.- B.2 Data plots.- C.0 OWL primitives.- C.1 OWL control primitives.- C.2 Compiler directives and declaration keywords.- C.3 Sensor primitives.- C.4 Valve command primitives.- C.5 I/O primitives.- C.6 Miscellaneous primitives.- D.0 The Trojan Cockroach.