Mobile vehicle

• US 8,049,902 B2
• Filed: 06/24/2005
• Issued: 11/01/2011
• Est. Priority Date: 07/01/2004
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ogawa, Tsuyoshi, Hara, Keisuke, Okazaki, Akihiro, Senoo, Toshihiro
• Primary Examiner(s): Chowdhury; Tarifur
• Assistant Examiner(s): AKANBI, ISIAKA O
• Application Number:
  US11/631,260
• Publication Number:
  US 20070203622A1
• Time in Patent Office: 2,321 Days
• Field of Search: 356/614, 153/19
• US Class Current: 356/614
• CPC Class Codes: G05D 1/0253 extracting relative motion information from a plurality of images taken successively, e.g. visual odometry, optical flow determining position or orientation from images G06T7/70

Abstract

A mobile vehicle provided with moving means and a moving control device automatically travels while detecting an advance distance and a turning angle by means of one optical displacement sensor. The mobile vehicle comprises a moving unit (2) for moving a body (1), one optical displacement sensor (7) as a displacement sensor provided on the body (1), and a moving control device for controlling the moving unit (2) based on a moving distance detected by the optical displacement sensor (7). The moving control device determines the distance of rectilinear movement and a turning angle of the body (1) from an amount detected by the optical displacement sensor (7). The optical displacement sensor (7) picks up patterns or the like on a traveling floor surface at specified time intervals and detects a moving distance by comparing images before and after the specified time.

Claims

1. A mobile vehicle, comprising:

a main body;

moving means for moving the main body, the moving means being provided on the main body;

a displacement sensor provided on the main body; and

movement control means for controlling the moving means on the basis of a detected value detected by the displacement sensor,

wherein the movement control means designates a pattern of movement of the mobile vehicle by the moving means for a forward/backward rectilinear movement or an in-place rotational movement;

the displacement sensor is only a single optical displacement sensor for taking images of a travel floor surface beneath the main body facing the displacement sensor, the displacement sensor being placed on the bottom of the main body at a position significantly off-center with respect to a rotation center around which the mobile vehicle performs the in-place rotational movement, the displacement sensor has, as displacement detection axes orthogonal two axes formed of a front-rear axis corresponding to a vehicle front-rear center line orthogonal to the rotation center axis line and a left-right axis parallel to a vehicle left-right center line orthogonal to the rotation center axis and perpendicular to the vehicle front-rear center line; and

the movement control means obtains, at specified time intervals, a forward/backward rectilinear movement distance and an in-place rotation angle, on the basis of data on changes between the images of the travel floor surface taken by the optical displacement sensor, by obtaining a forward/backward rectilinear movement distance as a displacement in the front-rear axis direction from the detected value with respect to the front-rear displacement detection axis direction, and by calculating an in-place rotation angle from displacement in the left-right axis direction obtained from the detected value with respect to the left-right displacement detection axis direction; and

wherein the movement control means obtains a current position of the mobile vehicle with respect to a starting point by integrating the obtained displacement in the front-rear axis direction and the obtained displacement in the left-right axis direction.

2. The mobile vehicle according to claim 1, wherein the optical displacement sensor has a spherical or curved surface that makes contact with the floor surface.

3. The mobile vehicle according to claim 1, wherein the optical displacement sensor has a body having a recess facing the floor surface, a CCD disposed inside the recess, and an LED that emits light against the floor surface.

4. The mobile vehicle according to claim 1, wherein the optical displacement sensor aims directly at the floor surface.

5. The mobile vehicle according to claim 1, wherein a resilient supporting member is provided for urging the displacement sensor against the floor surface, and the resilient supporting member is a spring damper.

6. The mobile vehicle according to claim 1, further comprising:

a working portion provided at one side of the main body with respect to the moving means,

wherein the working portion is a suction port.

7. The mobile vehicle according to claim 6, wherein the displacement sensor is provided at a side opposite to the one side with respect to the moving means, and a distance between the displacement sensor and the moving means is shorter than a distance between the working portion and the moving means.

8. The mobile vehicle according to claim 1, wherein the optical displacement sensor picks up images including patterns on the travelling floor surface at the specific time intervals, and the movement control means detects a moving distance by comparing images before and after the specified time interval.