Failsafe brake for a multi-wheel vehicle with motor controlled steering

• US 4,887,013 A
• Filed: 12/04/1987
• Issued: 12/12/1989
• Est. Priority Date: 08/30/1985
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Doth, Thomas J.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US07/129,914
• Time in Patent Office: 739 Days
• Field of Search: 318/2, 318/488, 318/489, 307/64, 307/5, 307/68, 74/388 PS, 180/6.2, 180/6.28, 180/6.44, 180/6.48, 180/6.5, 180/23, 180/79, 180/79.1
• US Class Current: 318/489
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0289 with means for avoiding collisions between vehicles vehicle fittings for automatically controlling speed including means for detecting potential obstacles B60K31/0008; avoiding obstacles by action on the steering system B62D; radar, sonar, lidar systems designed for anti-collision purposes G01S13/93, G01S15/93, G01S17/93
• CPC Class Codes: G05D 2201/0216 Vehicle for transporting goods in a warehouse, factory or similar

Abstract

A controllable mobile apparatus such as a mobile robot travels to a commanded destination under the control of a guidance system that provides speed and direction commands to the controllable mobile apparatus. A plurality of wheels carry the mobile apparatus to the commanded position in response to the speed commands from the guidance system. Steering commands will cause the selected members of the plurality of wheels to vary their angles by a predetermined amount in response to the steering commands that are provided by the guidance system. Additionally, a braking system is provided for stopping the controllable mobile apparatus when it encounters loss of power or communications with the guidance system.

Claims

1. A braking system for a mobile apparatus comprising:

at least two independently steerable wheels on said apparatus;

a power source for controlling the angle that each of said wheels makes with the mobile apparatus for steering; and

means for changing the angle between the wheels in order to brake the apparatus, including an auxiliary power source operable automatically upon failure of the power source for steering.

2. A brake for stopping an electrically powered automatically guided mobile robot upon failure of the source of electrical power for the robot, comprising:

a steering wheel steer motor;

a four pole, double throw relay which is energized by the robot electrical power source and which is de-energized upon failure of the robot electrical power source;

wherein a first two relay poles connect a capacitor to the power source when the relay is energized, to charge the capacitor and wherein the first two relay poles cooperate with a second two relay poles to connect the capacitor to the steer motor when the relay is de-energized;

wherein the second two relay poles connect steering control signals to the steer motor when the relay is energized, and wherein the second two relay poles cooperate with the first two relay poles to connect the capacitor to the steer motor when the relay is de-energized; and

wherein the stored charge causes the steer motor to change the angle between two wheels and thereby brake the robot.

3. A fail safe brake for a mobile apparatus comprising:

an automatically guided mobile robot with at least two wheels steerable independently of each other;

a steering motor;

a main electrical power supply;

an electrically energizable switch having a first position when energized and a second position when de-energized;

wherein the switch, when in said first position, conducts electrical steering control signals to the steering motor from the main electrical power supply, and wherein the switch, when in said second position, disconnects the main electrical power supply from the steering motor and conducts a second signal from a second power supply to the steering motor to change the angle between said at least two wheels to brake the mobile robot;

wherein the switch is energized when the main power supply is providing power, and the switch is de-energized when the main power supply is not providing power.

4. The fail safe brake of claim 3, wherein the switch is a relay.

5. The fail safe brake of claim 3, wherein the main electrical power supply is a battery.

6. The fail safe brake of claim 3, wherein the second power supply is a capacitor that is charged by the main power supply when the switch is in the first position.