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Title: Method for controlling a vehicle with two or more independently steered wheels

Patent ·
OSTI ID:869808
 [1];  [2]
  1. Oak Ridge, TN
  2. Knoxville, TN
+ Show Author Affiliations

A method (10) for independently controlling each steerable drive wheel (W.sub.i) of a vehicle with two or more such wheels (W.sub.i). An instantaneous center of rotation target (ICR) and a tangential velocity target (v.sup.G) are inputs to a wheel target system (30) which sends the velocity target (v.sub.i.sup.G) and a steering angle target (.theta..sub.i.sup.G) for each drive wheel (W.sub.i) to a pseudovelocity target system (32). The pseudovelocity target system (32) determines a pseudovelocity target (v.sub.P.sup.G) which is compared to a current pseudovelocity (v.sub.P.sup.m) to determine a pseudovelocity error (.epsilon.). The steering angle targets (.theta..sup.G) and the steering angles (.theta..sup.m) are inputs to a steering angle control system (34) which outputs to the steering angle encoders (36), which measure the steering angles (.theta..sup.m). The pseudovelocity error (.epsilon.), the rate of change of the pseudovelocity error ( ), and the wheel slip between each pair of drive wheels (W.sub.i) are used to calculate intermediate control variables which, along with the steering angle targets (.theta..sup.G) are used to calculate the torque to be applied at each wheel (W.sub.i). The current distance traveled for each wheel (W.sub.i) is then calculated. The current wheel velocities (v.sup.m) and steering angle targets (.theta..sup.G) are used to calculate the cumulative and instantaneous wheel slip (e, ) and the current pseudovelocity (v.sub.P.sup.m).

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
AC05-84OR21400
Assignee:
Martin Marietta Energy Systems, Inc. (Oak Ridge, TN)
Patent Number(s):
US 5402344
OSTI ID:
869808
Country of Publication:
United States
Language:
English

References (9)

Compliant-linkage kinematic design for multi-degree-of-freedom mobile robots conference May 1993
Experimental investigations of sensor-based surface following performed by a mobile manipulator report October 1994
Dynamics and simulation of compliant motion of a manipulator journal April 1988
A new wheel control system for the omnidirectional HERMIES-III robot journal July 1992
Position and force control of a vehicle with two or more steerable drive wheels report October 1992
Manipulators Constrained by Stiff Contact: Dynamics, Control, and Experiments journal August 1990
Vehicle Lateral Velocity and Yaw Rate Control With Two Independent Control Inputs journal December 1992
Model Following Control of Hybrid 4WD Vehicles journal August 1990
Rigid Body dynamics and decoupled control architecture for two strongly interacting manipulators journal December 1991

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method
controlling
vehicle
independently
steered
wheels
10
steerable
drive
wheel
instantaneous
center
rotation
target
icr
tangential
velocity
inputs
30
sends
steering
angle
theta
pseudovelocity
32
determines
compared
current
determine
error
epsilon
targets
angles
control
34
outputs
encoders
36
measure
rate
change
slip
pair
calculate
intermediate
variables
torque
applied
distance
traveled
calculated
velocities
cumulative
drive wheels
control variable
control variables
drive wheel
angle encoder
/701/180/