Method of determining the position of a landmark in the environment map of a self-propelled unit, the distance of the landmark from the unit being determined dynamically by the latter
First Claim
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1. A method of determining a position of a landmark in an environment map of a self-propelled unit, a distance of the landmark from the unit being determined dynamically by the unit, comprising the steps of:
- a) determining, at least by the unit, a position change using at least one first measuring device arranged on the unit;
b) determining, by the unit, at least one distance of a first obstacle in the environment relative to the unit using at least one second measuring device arranged on the unit, and entering the first obstacle in the environment map as a first landmark;
c) corresponding, at least at a starting position of the unit, the position of the unit and the location of the first landmark in the environment map to real relationships in the environment;
d) determining, after a movement of the unit away from the starting position, at least one first position of the unit relative to the starting position with a position uncertainty;
e) determining, from the first position of the unit, at least one first distance to the first obstacle with a location uncertainty and measuring a first distance to a suspected second obstacle, a determining landmark;
f) measuring, from a second position of the unit, at least one second distance to the suspected second obstacle;
g) calculating, for the second position of the unit, using the first distance to the first obstacle and a position change between the first position of the unit and the second position of the unit, a predicted second distance to the first obstacle and to the suspected second obstacle;
h) determining, as a system error, at least a difference between the measured second distance to the suspected second obstacle and the calculated predicted second distance to the suspected second obstacle; and
i) allocating, for determining the position of the first landmark, the position of the first landmark to the position of the suspected second obstacle in the environment map if a magnitude of the system error falls below a fixed value and is positive.
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Abstract
The method solves the problem of assigning surveyed landmarks to landmarks in an environment map by each measured value being compared with a predicted measured value which has previously been calculated on the basis of an earlier measurement. A dynamic limit is prescribed for this system error. The assignment of a measured value to a landmark and hence the determination of the position of this landmark in the environment is ensured by the system error being positive and falling below a specific value. In the event that such an assignment is no longer possible, the limit is dynamically raised, specifically until the ratio of predicted landmarks to assigned landmarks falls below a specific value. In order to avoid endless loops in the method, which may be produced by no assignment being possible, the method is broken off after a specific number of loops. The method is suitable for robots in domestic, office and industrial environments, as well as for transport vehicles.
70 Citations
12 Claims
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1. A method of determining a position of a landmark in an environment map of a self-propelled unit, a distance of the landmark from the unit being determined dynamically by the unit, comprising the steps of:
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a) determining, at least by the unit, a position change using at least one first measuring device arranged on the unit; b) determining, by the unit, at least one distance of a first obstacle in the environment relative to the unit using at least one second measuring device arranged on the unit, and entering the first obstacle in the environment map as a first landmark; c) corresponding, at least at a starting position of the unit, the position of the unit and the location of the first landmark in the environment map to real relationships in the environment; d) determining, after a movement of the unit away from the starting position, at least one first position of the unit relative to the starting position with a position uncertainty; e) determining, from the first position of the unit, at least one first distance to the first obstacle with a location uncertainty and measuring a first distance to a suspected second obstacle, a determining landmark; f) measuring, from a second position of the unit, at least one second distance to the suspected second obstacle; g) calculating, for the second position of the unit, using the first distance to the first obstacle and a position change between the first position of the unit and the second position of the unit, a predicted second distance to the first obstacle and to the suspected second obstacle; h) determining, as a system error, at least a difference between the measured second distance to the suspected second obstacle and the calculated predicted second distance to the suspected second obstacle; and i) allocating, for determining the position of the first landmark, the position of the first landmark to the position of the suspected second obstacle in the environment map if a magnitude of the system error falls below a fixed value and is positive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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11. The method as claimed in claim 10, wherein R(k+1)=0.
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12. The method as claimed in claim 10, wherein γ
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max =4, m γ
n =2max n=3 and the reliability limit is 1.5.
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max =4, m γ
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Specification
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Current AssigneeSiemens AG
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Original AssigneeSiemens AG
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InventorsRencken, Wolfgang
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Primary Examiner(s)Zanelli, Michael J.
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Application NumberUS08/809,276Time in Patent Office937 DaysField of Search701/23, 701/25, 701/300, 701/301, 701/225, 348/116, 702/165US Class Current701/23CPC Class CodesG05D 1/024 in combination with a laser...G05D 1/0255 using acoustic signals, e.g...G05D 1/0272 comprising means for regist...G05D 1/0274 using mapping information s...
