--- title: "Learning and executing generalized robot plans — Fikes 1972" description: "The authors add a generalization stage that replaces the problem-specific constants in a finished… 6 references, cited by 19 papers here." authors: ["Richard E. Fikes", "Peter E. Hart", "Nils J. Nilsson"] year: 1972 venue: "Artificial Intelligence" source: "http://ai.stanford.edu/~nilsson/OnlinePubs-Nils/PublishedPapers/" licence: "All rights reserved — free to read at the source" summary_licence: "Elamur Cosmic License" canonical: "https://research.elamur.ai/free/en/papers/fikes-1972-learning-executing-generalized-robot-plans/" --- [Elamur Research](https://md.research.elamur.ai/free/en/) · [this page in HTML](https://research.elamur.ai/free/en/papers/fikes-1972-learning-executing-generalized-robot-plans/) [home](https://md.research.elamur.ai/free/en/) / [papers](https://md.research.elamur.ai/free/en/papers/) / [1972](https://md.research.elamur.ai/free/en/papers/1972/) / Learning and executing generalized robot plans # Learning and executing generalized robot plans **Authors:** [Richard E. Fikes](https://md.research.elamur.ai/free/en/authors/richard-e-fikes/), Peter E. Hart and [Nils J. Nilsson](https://md.research.elamur.ai/free/en/authors/nils-j-nilsson/) · **Year:** 1972 · **Venue:** [Artificial Intelligence](https://md.research.elamur.ai/free/en/venues/artificial-intelligence/) ([Artificial Intelligence 1972](https://md.research.elamur.ai/free/en/venues/artificial-intelligence/1972/)) · **Publisher:** [Elsevier BV](https://md.research.elamur.ai/free/en/publishers/elsevier-bv/) · **Licence:** All rights reserved — free to read at the source **Links:** [PDF](http://ai.stanford.edu/~nilsson/OnlinePubs-Nils/PublishedPapers/learningexecuting.pdf) · [OpenAlex](https://openalex.org/W2020149918) **Citations:** 1,019 citations (OpenAlex, 2026-10-14) · [19](https://md.research.elamur.ai/free/en/papers/fikes-1972-learning-executing-generalized-robot-plans/cited-by/) in our library, of the 149,439 papers whose bibliographies we read ## Summary The paper extends two components of an SRI mobile-robot system: the planner STRIPS and the execution monitor PLANEX. Their tasks include pushing boxes between rooms and passing through doors. Before this work, every plan was built from scratch. A failure during execution also forced the robot to repeat exactly the same steps. The authors add a generalization stage that replaces the problem-specific constants in a finished STRIPS plan with parameters, so one plan covers a family of tasks. The result is stored in a triangle table, which records the conditions under which each remaining tail of the plan still works. Stored plans, called MACROPs, are used in two ways. STRIPS treats a whole MACROP, or a fragment of it, as a single macro operator when solving new problems. PLANEX uses the same structure to choose a new binding of the parameters when the world differs from expectations. Experiments show plans accumulating into long sequences that STRIPS could not otherwise find. The work is an early demonstration of learning inside automated planning. ## Key points - **Operator model:** STRIPS describes each operator by a precondition wff, an add list and a delete list. It proves goals with the QA3 resolution theorem prover. - **Triangle table:** this format exposes most of the 2^n − 1 legitimate subsequences of an n-step plan, so any of them can be reused as a unit. Its "kernels" give the preconditions for executing the remaining part of a plan. - **Robust execution:** in a seven-room test environment, a box blocked a door. PLANEX re-instantiated the generalized plan and sent the robot through a different room to reach its target. - **Long plans:** a sequence of eight learning problems produced a 19-operator MACROP that fetches three boxes from three rooms and pushes them together. It absorbed the seven earlier MACROPs. - **Open problems:** the authors name three. Preconditions need to be abstracted so large macros stay tractable, old plans need to be forgotten, and operator models should be corrected from observed behavior. (Artificial Intelligence 3, 1972, pp. 251–288.) *Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.* ## Institutions - [SRI International](https://md.research.elamur.ai/free/en/labs/sri-international/) — Research institute, Menlo Park, United States · 25 works · 13,213 citations 📚 Shelves (2): [🖥️ Computer Science](https://md.research.elamur.ai/free/en/shelves/computer-science/) · 19,503 works · [🤖 Artificial Intelligence](https://md.research.elamur.ai/free/en/shelves/computer-science/artificial-intelligence/) · 18,805 works ## Cite Cite as: Richard E. Fikes, Peter E. Hart and Nils J. Nilsson. 1972. Learning and executing generalized robot plans. Artificial Intelligence. The paper itself, not this page. BibTeX from the library's record of the work. ```bibtex @inproceedings{fikes1972learning, title = {{Learning and executing generalized robot plans}}, author = {Richard E. Fikes, Peter E. Hart and Nils J. Nilsson}, booktitle = {Artificial Intelligence}, year = {1972}, doi = {10.1016/0004-3702(72)90051-3}, url = {https://doi.org/10.1016/0004-3702(72)90051-3} } ``` - [next → Erce and Other Possibly Keltic Elements In the Old English Charm for Unfruitful Land](https://md.research.elamur.ai/free/en/papers/duckert-1972-erce-other-possibly-keltic-elements/) - [↑ back to papers of 1972](https://md.research.elamur.ai/free/en/papers/1972/) ## References 6 references, 1 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet. 1. Fikes, R. E. and Nilsson, N. J. [STRIPS: A new approach to the application of theorem proving to problem solving](https://md.research.elamur.ai/free/en/papers/fikes-1971-strips-new-approach-application-theorem/). Artificial Intelligence 2 ( 197 i), 189-208. Artificial Intelligence $ (! 972), 251-288 2. Fikes, R. E. Monitored execution of robot plans produced by STRIPS. Proc. IFIP CongTess 71, Ljubljana, Yugoslavia (August 23-28, 1971). [find](https://scholar.google.com/scholar?q=Fikes%2C+R%2E+E%2E+Monitored+execution+of+robot+plans+produced+by+STRIPS%2E+Proc%2E+IFIP+CongTess+71%2C+Ljubljana%2C+Yugoslavia+%28August+23%2D28%2C+1971%29%2E) 3. Garvey, T. D. and Kling, It. E. U~r's Guide ,,o QA3.$ Question-Answering System. Technical Note 15, Artificial Inteilisenoe Group, Stanford Research Institute, Menlo Park, California (December 1969). [find](https://scholar.google.com/scholar?q=Garvey%2C+T%2E+D%2E+and+Kling%2C+It%2E+E%2E+U%7Er%27s+Guide+%2C%2Co+QA3%2E%24+Question%2DAnswering+System%2E+Technical+Note+15%2C+Artificial+Inteilisenoe+Group%2C+Stanford+Research+Institute%2C+Menlo+Park%2C+California+%28December+1969%29%2E) 4. Raphael, B. et al. Reseerch and Applications--Artificial Intelligence. Final Report, Contract NASW.2164, Stanford Research Institute, Menlo Park, California (December 1971). [find](https://scholar.google.com/scholar?q=Raphael%2C+B%2E+et+al%2E+Reseerch+and+Applications%2D%2DArtificial+Intelligence%2E+Final+Report%2C+Contract+NASW%2E2164%2C+Stanford+Research+Institute%2C+Menlo+Park%2C+California+%28December+1971%29%2E) 5. Hart, P.E. and Nilsson, N. J. Shakey: Experiments in Robot Planning and Learning. Film prod.~ced at Stanford Research Institute, Menlo Park, California (1972). [find](https://scholar.google.com/scholar?q=Hart%2C+P%2EE%2E+and+Nilsson%2C+N%2E+J%2E+Shakey%3A+Experiments+in+Robot+Planning+and+Learning%2E+Film+prod%2E%7Eced+at+Stanford+Research+Institute%2C+Menlo+Park%2C+California+%281972%29%2E) 6. Ernst, G. andNewell, A. GPS: A Case Study in Generality and Problem Solving. ACM Monograph Series. Academic Press, New York, New York, 1969. Received July 1972; revised version received September 1972. Artificial Intelligence 3 (1972), 251-288 [find](https://scholar.google.com/scholar?q=Ernst%2C+G%2E+andNewell%2C+A%2E+GPS%3A+A+Case+Study+in+Generality+and+Problem+Solving%2E+ACM+Monograph+Series%2E+Academic+Press%2C+New+York%2C+New+York%2C+1969%2E+Received+July+1972%3B+revised+version+received+September+1972) *Updated 3 November 2026*