yamauchi@cs.rochester.edu (Brian Yamauchi) (01/16/91)
As part of my thesis research in behavior-based robotics, I'm going to be building a simulated robot control system for freeway driving, and I'd like to include reasonable assumptions about automobile dynamics in the simulator. In particular, I'm interested in the following functions for typical automobiles: 1) Maximum acceleration as a function of speed 2) Maximum deceleration as a function of speed 3) Maximum change in heading as a function of speed 4) Interactions between turning and max acceleration 5) Interactions between turning and max deceleration Of course, the actual values will depend on whether you're driving a Ferrari or a Yugo, but I'm interested in the general shape of the curve for your average coupe or sedan. A subject search in our library shows scores of references on automobile industry & trade, automobile workers & labor unions, environmental effects of automobiles, social aspects of automobiles, and even a book of poetry about automobile factories, but nothing about automobile performance or dynamics. Thanks in advance, -- _______________________________________________________________________________ Brian Yamauchi University of Rochester yamauchi@cs.rochester.edu Computer Science Department _______________________________________________________________________________
laforce@krypton.arc.nasa.gov (Soren LaForce) (01/17/91)
In article <YAMAUCHI.91Jan15180754@heron.cs.rochester.edu>, yamauchi@cs.rochester.edu (Brian Yamauchi) writes... > >As part of my thesis research in behavior-based robotics, I'm going to >be building a simulated robot control system for freeway driving, and >I'd like to include reasonable assumptions about automobile dynamics >in the simulator. > stuff deleted > > Thanks in advance, >-- >_______________________________________________________________________________ > >Brian Yamauchi University of Rochester >yamauchi@cs.rochester.edu Computer Science Department >_______________________________________________________________________________ Ok, you asked. The department of transportation (DOT) funds research in a variety of vehicle properties, i.e. dynamics and the simulation of dynamics. I have in front of me the final report of DOT contract number: DOT HS-7-01715. The report number is: DOT-HS-805-370. The report is titled: Improvement of Mathematical Models for Simulation of Vehicle Handling (Vol 7: Technical Manual for the General Simulation). Does this sound like what you need? The document is available to the U.S. public through the National Technical Information Service, Springfield, Virginia, 22161 The report is 278 pages. It is a **RIGOROUS** mathematical model. I suspect that it is more detailed than what you need. If you are interested, I may be able to provide a simplistic vehicle model, i.e. no tire model, and about 1 page of alegbra. I will have to make sure it is ok to release information before sending it. If you are interested, please e-mail me directly at: laforce@krypton.arc.nasa.gov Best, Soren LaForce
hollombe@ttidca.TTI.COM (The Polymath) (01/17/91)
In article <YAMAUCHI.91Jan15180754@heron.cs.rochester.edu> yamauchi@cs.rochester.edu (Brian Yamauchi) writes: }As part of my thesis research in behavior-based robotics, I'm going to }be building a simulated robot control system for freeway driving, and }I'd like to include reasonable assumptions about automobile dynamics }in the simulator. There are several insurance companies, and consultants to them, who do computerized automobile accident simulations to present as evidence in court cases. The software is probably proprietary, but they might be willing to tell you their sources for the information you want. Sorry, I don't have any specific names. -- The Polymath (aka: Jerry Hollombe, M.A., CDP, aka: hollombe@ttidca.tti.com) Head Robot Wrangler at Citicorp(+)TTI Illegitimis non 3100 Ocean Park Blvd. (213) 450-9111, x2483 Carborundum Santa Monica, CA 90405 {csun | philabs | psivax}!ttidca!hollombe
jennings@svax.cs.cornell.edu (Jim Jennings) (01/18/91)
In article <YAMAUCHI.91Jan15180754@heron.cs.rochester.edu> yamauchi@cs.rochester.edu (Brian Yamauchi) writes: > >As part of my thesis research in behavior-based robotics, I'm going to >be building a simulated robot control system for freeway driving, and >I'd like to include reasonable assumptions about automobile dynamics >in the simulator. [info wish list deleted] If you really only want to make some guesses about maximum accelerations, velocities, and such, buy a few issues of Road and Track magazine. When they review a car, they give you these sorts of specs, including torque and hp curves, from which you can derive some of what you need. Most useful to you might be velocity curves of the 0-x mph runs. *However*, I think you're totally at sea if you expect to learn anything from this kind of simulation. How will you model changing grip due to tread deformation, road surface, tire pressure, sidewall windup, suspension geometry, tire temperature, tire compound, road material, slip rate and angle, etc.? And this is only the tip of the iceberg when it comes to analyzing automobile handling. You could argue that some of these effects on the trajectory of your modeled vehicle are negligible, but if you want to know about the extremes of adhesion in turns, acceleration, and braking, then I won't believe your arguments. If you want to use a behavior-based system (or any other, really) to control a vehicle with nontrivial dynamics, my suggestion is to build a (real) vehicle that can travel at sufficient (scale) speed. --Jim Jennings --Cornell Computer Science Robotics Lab
yamauchi@cs.rochester.edu (Brian Yamauchi) (01/18/91)
In article <50852@cornell.UUCP> jennings@svax.cs.cornell.edu (Jim Jennings) writes: In article <YAMAUCHI.91Jan15180754@heron.cs.rochester.edu> yamauchi@cs.rochester.edu (Brian Yamauchi) writes: > >As part of my thesis research in behavior-based robotics, I'm going to >be building a simulated robot control system for freeway driving, and >I'd like to include reasonable assumptions about automobile dynamics >in the simulator. How will you model changing grip due to tread deformation, road surface, tire pressure, sidewall windup, suspension geometry, tire temperature, tire compound, road material, slip rate and angle, etc.? And this is only the tip of the iceberg when it comes to analyzing automobile handling. The goal of this research is not to study automobile handling, but to demonstrate a behavior arbitration algorithm which can deal with large numbers of possibly conflicting sensorimotor constraints. I don't claim this will generate any new insights into the analysis of automobile performance, although I do hope it will provide insights into how to build reactive robots which need to resolve conflicts between behavior agents. If you want to use a behavior-based system (or any other, really) to control a vehicle with nontrivial dynamics, my suggestion is to build a (real) vehicle that can travel at sufficient (scale) speed. This would have been my first choice by far, but, alas, the resources are unavailable. However, this vehicle simulation is only part of my thesis research. I also plan to demonstrate by behavior arbitration algorithm by building a (real) visually-guided dextrous manipulation system (an area in which we do have the robotics/vision hardware). I have a strong personal preference for working with real robots, and I agree that building real systems is the best way to demonstrate robotic algorithms, but sometimes you just don't have an ALV handy... -- _______________________________________________________________________________ Brian Yamauchi University of Rochester yamauchi@cs.rochester.edu Computer Science Department _______________________________________________________________________________
nagle@well.sf.ca.us (John Nagle) (01/19/91)
As mentioned above, some very detailed models of automobile handling are available. Existing models are good enough to predict vehicle behavior even under extreme conditions. The first really good model was developed at the Cornell Aeronautical Laboratory (now Calspan) back in the 1970s. As a demonstration of its validity, it was used to design a set of ramps for a car stunt in which a car executed a 360 degree roll in the air and landed smoothly on the landing ramp. (A version of this stunt can be seen in one of the James Bond movies; the ramps look like the ruins of a bridge, but were very carefully calculated. A movie credit appears for the computation.) The California Department of Transportation (Caltrans) has been doing some simulations of automated freeway driving, although their model is 2D and has rather simplistic dynamics. Contact the Caltrans PATH (Programs to Automate the Highway) office in Sacramento. John Nagle