Electric vehicle and method of controlling the same

• US 8,706,332 B2
• Filed: 05/27/2010
• Issued: 04/22/2014
• Est. Priority Date: 06/02/2009
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kume, Yohei, Kawakami, Hideo, Nakamura, Tohru
• Primary Examiner(s): Algahaim, Helal A
• Assistant Examiner(s): Nguyen, Nga X
• Application Number:
  US13/146,097
• Publication Number:
  US 20110313604A1
• Time in Patent Office: 1,426 Days
• Field of Search: 701/22, 180/6.5, 180/19.3
• US Class Current: 701/22
• CPC Class Codes: A61G 2203/14 Joysticks
• CPC Class Codes: A61G 5/04 motor-driven A61G5/06 takes precedence; motor-operated rests A61G5/12; for vehicles with handlebars, equipped with three or more wheels B62K5/003, B62K5/023
• CPC Class Codes: A61G 5/048 Power-assistance activated by pushing on hand rim or on handlebar
• CPC Class Codes: B60L 2200/24 Personal mobility vehicles
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B62B 2301/06 Steering all wheels together simultaneously
• CPC Class Codes: B62B 3/001 Steering devices
• CPC Class Codes: B62B 3/14 characterised by provisions for nesting or stacking, e.g. shopping trolleys collapsible shopping trolleys B62B3/027
• CPC Class Codes: B62B 5/0043 One motor drives one wheel
• CPC Class Codes: B62B 5/0069 Control
• CPC Class Codes: B62B 5/0073 Measuring a force
• CPC Class Codes: B62B 5/0404 automatic
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

The present invention has an object of providing an electric vehicle which makes an assisting movement based on an operation by an operator without making a movement when an operator is not operating the electric vehicle or a movement which widely differs from a movement intended by the operator in direction or distance, and a method of controlling the electric vehicle. The electric vehicle (1) includes an operating force measurement unit (4) which measures an operating force applied by an operator (13) to the electric vehicle (1), an obstacle measurement unit (8) which measures a distance and a direction from the electric vehicle (1) to an obstacle, a virtual repulsive force calculation unit (9) which calculates a virtual repulsive force having a magnitude inversely proportional to a magnitude of the distance measured by the obstacle measurement unit (8) and a direction opposite to the direction to the obstacle, and an assisting force calculation unit (10) which calculates an assisting force for moving the electric vehicle (1) based on a resultant force of the operating force and the virtual repulsive force. The assisting force calculation unit (10) has an upper limit X to a magnitude of the calculated assisting force, and sets the upper limit X based on a magnitude of the operating force and an angle between a direction of the operating force and a direction of the resultant force.

Claims

1. An electric vehicle comprising:

a control input measurement unit configured to measure a magnitude and a direction of a control input provided by an operator to said electric vehicle;

an obstacle measurement unit configured to measure a position vector of an obstacle in relation to said electric vehicle as an origin;

a target movement velocity calculation unit configured to calculate a target movement velocity of said electric vehicle, the target movement velocity being based on the magnitude and direction of the control input measured by said control input measurement unit;

an obstacle avoidance velocity calculation unit configured to calculate, based on the position vector determined by said obstacle measurement unit, an obstacle avoidance velocity at which said electric vehicle is moved away from said obstacle; and

an assisting movement velocity calculation unit configured to (i) calculate an assisting movement velocity for moving said electric vehicle based on a net velocity of the target movement velocity and the obstacle avoidance velocity, (ii) calculate an upper limit Y to a magnitude of the calculated assisting movement velocity based on the target movement velocity, (iii) and output information on an assisting movement velocity equal to or smaller than the upper limit Y when the calculated assisting movement velocity exceeds the upper limit;

wherein said assisting movement velocity calculation unit is configured to calculate the upper limit Y based on an angle between a direction of the target movement velocity and a direction of the net velocity.

2. The electric vehicle according to claim 1,

wherein said assisting movement velocity calculation unit is configured to set a magnitude of the target movement velocity as the upper limit Y.

3. The electric vehicle according to claim 1,

wherein said assisting movement velocity calculation unit is configured to calculate the upper limit Y such that the upper limit Y decreases as an angle between a direction of the target movement velocity and the direction of the net velocity increases.

4. The electric vehicle according to claim 1,

wherein, when an angle θ

^ope_sum between a direction of the target movement velocity and a direction of the net velocity is within a range of 60°

>

θ

^ope_sum>

−

60°

, said assisting movement velocity calculation unit is configured to set a magnitude of the target movement velocity as the upper limit Y.

5. The electric vehicle according to claim 1,

wherein, when an angle θ

^ope_sum between a direction of the target movement velocity and a direction of the net velocity is equal to or larger than 60°

or equal to or smaller than −

60°

, said assisting movement velocity calculation unit is configured to set a magnitude of the upper limit Y to zero.

6. The electric vehicle according to claim 1,

wherein said assisting movement velocity calculation unit is configured to calculate the upper limit Y such that the upper limit Y decreases as an angle between a direction of the target movement velocity and a direction I set for said electric vehicle increases.

7. The electric vehicle according to claim 1,

wherein, when an angle between a direction of the target movement velocity and a direction I set for said electric vehicle is within a range between 0°

and 45°

, said assisting movement velocity calculation unit is configured to set a magnitude of the target movement velocity as the upper limit Y or leave the upper limit Y unchanged.

8. The electric vehicle according to claim 4,

wherein, when the target movement velocity includes a rotational component, at least one of the angle θ

^ope_sum and an angle θ

^ref_ope between a direction of the target operation velocity and a direction I set for said electric vehicle is increased in a direction of the rotational component.