Navigation System and Navigation Method of Route Planning Using Variations of Mechanical Energy
First Claim
1. A navigation system for searching a route to a destination and guiding a vehicle to the destination, the navigation system comprising:
- a road map data storage unit storing road map data including altitude information;
an energy variation calculation unit for calculating a variation of mechanical energy of the vehicle travelling on a road link included in the road map data; and
a route-search unit for searching for a fuel-efficient route for the vehicle based on the variation of mechanical energy calculated by the energy variation calculation unit,wherein the energy variation calculation unit;
divides the road link to be used for route-searching into a plurality of sub-links each approximated by a line segment;
calculates the variation of mechanical energy of the vehicle travelling on the plurality of the sub-links in an acceleration travel mode, a deceleration travel mode, and a constant-speed travel mode, wherein each of the variations of mechanical energy includes a total variation of friction energy based on a length of each sub-link calculated from coordinate information, potential energy based on an altitude difference of both ends of each sub-link calculated by the coordinate information including the altitude information, and kinetic energy;
categorizes the sub-links in accordance with an estimated fuel consumption in each of the acceleration travel mode, the deceleration travel mode, and the constant-speed travel mode into a first category in which the estimated fuel consumption is equal to a minimum fuel consumption of the vehicle in all of the acceleration, deceleration and constant-speed travel modes, a second category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration travel mode but is equal to the minimum fuel consumption in the deceleration and constant-speed travel modes, a third category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration and constant-speed travel modes but is equal to the minimum fuel consumption in the deceleration travel mode, or a fourth category in which the estimated fuel consumption is not equal to the minimum fuel consumption in all of the acceleration, deceleration and constant-speed travel modes;
calculates a sum of the variations, per each categorized sub-link, of mechanical energy that is the total variation of friction energy, potential energy, and kinetic energy of the vehicle travelling on the plurality of sub-links of the road link; and
renders the sum calculated per each categorized sub-link as a geometry parameter of the road link and stores the geometry parameter in a geometry parameter storage unit.
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Abstract
A central device uses a link shape compression unit to compress information of shape of ups and downs of a road link obtained from a three-dimensional road map, and calculates a geometry parameter based on variation of energy of a vehicle travelling on the road link. An on-board terminal device estimates the vehicle'"'"'s average travelling pattern by using a travel-pattern-estimation unit based on the geometry parameter calculated by the central device, a link-travelling time estimated from statistically-stored traffic information, and a link length. The on-board terminal device further calculates fuel consumption of the vehicle travelling on each road link based on the estimated travelling pattern and parameters of the vehicle by using a fuel-consumption calculation unit, and then, searches a fuel-efficient route by using the fuel consumption as a link cost. The on-board terminal device has a vehicle-type selector for selecting a type of the vehicle.
27 Citations
6 Claims
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1. A navigation system for searching a route to a destination and guiding a vehicle to the destination, the navigation system comprising:
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a road map data storage unit storing road map data including altitude information; an energy variation calculation unit for calculating a variation of mechanical energy of the vehicle travelling on a road link included in the road map data; and a route-search unit for searching for a fuel-efficient route for the vehicle based on the variation of mechanical energy calculated by the energy variation calculation unit, wherein the energy variation calculation unit; divides the road link to be used for route-searching into a plurality of sub-links each approximated by a line segment; calculates the variation of mechanical energy of the vehicle travelling on the plurality of the sub-links in an acceleration travel mode, a deceleration travel mode, and a constant-speed travel mode, wherein each of the variations of mechanical energy includes a total variation of friction energy based on a length of each sub-link calculated from coordinate information, potential energy based on an altitude difference of both ends of each sub-link calculated by the coordinate information including the altitude information, and kinetic energy; categorizes the sub-links in accordance with an estimated fuel consumption in each of the acceleration travel mode, the deceleration travel mode, and the constant-speed travel mode into a first category in which the estimated fuel consumption is equal to a minimum fuel consumption of the vehicle in all of the acceleration, deceleration and constant-speed travel modes, a second category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration travel mode but is equal to the minimum fuel consumption in the deceleration and constant-speed travel modes, a third category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration and constant-speed travel modes but is equal to the minimum fuel consumption in the deceleration travel mode, or a fourth category in which the estimated fuel consumption is not equal to the minimum fuel consumption in all of the acceleration, deceleration and constant-speed travel modes; calculates a sum of the variations, per each categorized sub-link, of mechanical energy that is the total variation of friction energy, potential energy, and kinetic energy of the vehicle travelling on the plurality of sub-links of the road link; and renders the sum calculated per each categorized sub-link as a geometry parameter of the road link and stores the geometry parameter in a geometry parameter storage unit. - View Dependent Claims (2)
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3. A navigation method using a navigation device having a road map data storage unit having road map data including altitude information, the navigation method comprising the steps, carried out by the navigation device for searching a route and guiding a vehicle to a destination, of:
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(a) calculating a variation of mechanical energy of the vehicle travelling on a road link included in the road map data; and (b) searching a fuel-efficient route for the vehicle based on the calculated variation of mechanical energy, wherein step (a) comprises; (i) dividing the road link to be used for route-searching into a plurality of sub-links each approximated by a line segment; (ii) calculating the variation of mechanical energy of the vehicle travelling on the plurality of sub-links in each of an acceleration travel mode, a deceleration travel mode, and a constant-speed travel mode, wherein each of the variations of mechanical energy includes a total variation of friction energy based on lengths of the plurality of sub-links calculated from coordinate information, potential energy based on an altitude difference of both ends of each sub-link calculated from the coordinate information including the altitude information, and kinetic energy; (iii) categorizing the sub-links in accordance with an estimated fuel consumption in each of the acceleration travel mode, the deceleration travel mode, and the constant-speed travel mode into a first category in which the estimated fuel consumption is equal to a minimum fuel consumption of the vehicle in all of the acceleration, deceleration and constant-speed travel modes, a second category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration travel mode, but is equal to the minimum fuel consumption in the deceleration and constant-speed travel modes, a third category in which the estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration and constant-speed travel modes, but is equal to the minimum fuel consumption in the deceleration travel mode, or a fourth category in which the estimated fuel consumption is not equal to the minimum fuel consumption in all of the acceleration, deceleration and constant-speed travel modes; (iv) calculating a sum of the variations, per each categorized sub-link, of mechanical energy that is the total variation of friction energy, potential energy, and kinetic energy of the vehicle travelling the plurality of sub-links of the road link; and (v) rendering the sum calculated per each categorized sub-link as a geometry parameter of the road link and stores the geometry parameter in a geometry parameter storage unit. - View Dependent Claims (4)
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5. A navigation system comprising:
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a road map data storage unit storing road map data therein; a geometry parameter storage unit for storing data of variations of energy calculated previously for road links included in the road map data by using altitude information, the data of variations of energy being stored as a geometry parameter; an energy variation calculation unit for calculating the variation of energy of the vehicle travelling on each road link included in the road map data based on the data of the variation of energy according to each travel pattern of the vehicle, calculating a sum of the variations, per each of a plurality of categorized sub-links, of mechanical energy that is the total variation of friction energy, potential energy, and kinetic energy of the vehicle travelling on the plurality of sub-links of the road link, and rendering the sum calculated per each categorized sub-link as a geometry parameter of the road link; and a route-search unit for searching a fuel-efficient route for the vehicle based on the variation of energy calculated by the energy variation calculation unit, wherein the geometry parameter storage unit stores the sum of variations, per each categorized sub-link, of mechanical energy that is a total variation of friction energy, potential energy, and kinetic energy of the vehicle travelling sub-links of the road link as the geometry parameter of the road link, the sub-links being categorized in accordance with an estimated fuel consumption in each of an acceleration travel mode, a deceleration travel mode, and the constant-speed travel mode into a first category in which the estimated fuel consumption is equal to a minimum fuel consumption of the vehicle in all of the acceleration, deceleration and constant-speed travel modes, a second category in which estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration travel mode, but is equal to the minimum fuel consumption in the deceleration and constant-speed travel modes, a third category in which estimated fuel consumption is not equal to the minimum fuel consumption in the acceleration and constant-speed travel modes, but is equal to the minimum fuel consumption in the deceleration travel mode, or a fourth category in which estimated fuel consumption is not equal to the minimum fuel consumption in all of the acceleration, deceleration and constant-speed travel modes, wherein each sub-link is approximated by a line segment. - View Dependent Claims (6)
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Specification