US 11,858,128 B1
Rapid braking system for an autonomous mobile device
Benny Ng, San Leandro, CA (US); Siddharth Gupta, Redwood City, CA (US); Marcel Colman Eric Stieber, Sunnyvale, CA (US); Rex L Allison, Santa Clara, CA (US); and Christopher Wells Fitzhugh, San Jose, CA (US)
Assigned to AMAZON TECHNOLOGIES, INC., Seattle, WA (US)
Filed by AMAZON TECHNOLOGIES, INC., Seattle, WA (US)
Filed on Jun. 28, 2018, as Appl. No. 16/022,527.
Int. Cl. B25J 9/00 (2006.01); B25J 9/16 (2006.01); B25J 11/00 (2006.01); H02M 1/08 (2006.01)
CPC B25J 9/0009 (2013.01) [B25J 9/1666 (2013.01); B25J 9/1694 (2013.01); B25J 11/008 (2013.01); H02M 1/08 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A robot comprising:
one or more sensors;
a brushless direct current motor (motor) having a first terminal, a second terminal, and a third terminal, wherein a shaft of the motor is coupled to a wheel;
a battery;
a relay comprising:
a coil with a first coil terminal connected to an output terminal and a second coil terminal connected to the second terminal of the motor;
a first contact connected to a first fuse terminal of a first fuse, wherein a second fuse terminal of the first fuse is connected to the second terminal of the motor; and
a second contact connected to the first terminal of the motor;
one or more processors to execute instructions to:
receive sensor data from the one or more sensors;
determine, based on the sensor data, occurrence of a stop condition; and
generate a stop signal responsive to the stop condition; and
electronic circuitry to, responsive to the stop signal:
operate a first switching mechanism to disconnect the first terminal of the motor from the battery;
operate a braking circuit to dissipate, at a predetermined rate, power produced by motion of the motor; and
responsive to a back electromotive force (EMF) produced by the motor that is below a threshold value, operate a stop circuit that when the coil is deenergized connects the first contact and the second contact.