MOBILE ROBOT AND TRAVELLING METHOD FOR THE SAME

• US 20110137462A1
• Filed: 12/02/2010
• Published: 06/09/2011
• Est. Priority Date: 12/03/2009
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Amino, Azusa, NAKAMURA, Ryosuke
• Granted Patent: US 9,162,355 B2
• Time in Patent Office: Days
• US Class Current: 700/253
• CPC Class Codes: B25J 5/007 mounted on wheels
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

This mobile unit suppresses lateral vibration produced when the mobile unit passes over a step. A stabilizer according to the present invention predicts contact timing at which the mobile unit makes contact with a step, which may be a bump or pit, using sensor information or map information, shifts the center of gravity of the mobile unit laterally by controlling actuators, and shits the center of gravity laterally for the next step after detecting that the mobile unit has passed over the previous step.

Claims

1. A mobile robot including a plurality of wheels that are suspended by a main body of the mobile robot and travel on a floor surface, a drive mechanism that rotates the wheels, and a drive controller that controls the drive mechanism, comprising:

actuators that are provided to adjust the distance between the mobile robot and the wheels;

a suspension control unit that controls the actuators;

a sensor that detects steps on the floor surface; and

a step prediction unit that predicts the time at which the step makes contact with the wheels from the sensor and the speed of the mobile unit;

wherein

the suspension control unit controls suspensions to shift the center of gravity in a direction in which impact produced by contact between a step on the floor surface and one of the wheels is mitigated.

2. The mobile robot according to claim 1, wherein

when the mobile robot moves down to a pit with one wheel at a time, the suspension control unit shifts the center of gravity in a direction opposite to the other wheel that next moves down the pit in advance by controlling the actuators.

3. The mobile robot according to claim 1, wherein

when a step detecting unit detecting the movement of the wheels over bumps and pits detects that the wheels have passed over a bump or pit, the suspension control unit shifts the center of gravity back to the center of the mobile robot.

4. The mobile robot according to claim 1, wherein

the suspension control unit adjusts an amount of center of gravity shift of the mobile robot according to an interval of time, predicted by the step prediction unit, at which the right and left wheels make contact with a bump or pit.

5. A travelling method for a mobile robot including a step detecting sensor that detects steps, the method comprising the steps of:

detecting the direction to a step and the height of the step obtained by the step detecting sensor;

measuring the distance between the step and the mobile robot;

calculating contact timing at which the mobile robot makes contact with the step based on a target travelling speed;

shifting the center of gravity to the side of a wheel that makes contact with the step first by controlling suspensions upon contact with the step;

shifting the center of gravity to the side of the wheel that makes contact with the step first until the wheel passes over the step and then the other wheel makes contact with the step; and

shifting the center of gravity back to the center of the mobile robot upon detection that both wheels have passed over the step.

6. The travelling method according to claim 5, wherein

the height of and direction to the step are obtained from map information.