# US 2021/0129328 A1 · Braking stepper motors in robotic systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0129328 A1 - Document ID: US20210129328A1 - Status: Published application - Kind: A1 - Application number: 16/674,483 - Filed: 2019-11-05 - Published: 2021-05-06 - Earliest claimed: 2019-11-05 - Assignees: Elementary Robotics, Inc. - Applicants: Elementary Robotics, Inc. - Inventors: Dan Pipe-Mazo; Arye Barnehama; Arash Kalantari - Web page: https://patentgrep.com/patent/US20210129328A1 ## CPC - B25J 9/1664: {characterised by motion, path, trajectory planning} - B25J 9/0084: {comprising a plurality of manipulators} - B25J 9/126: {Rotary actuators} - G05B 2219/31136: Name of bus, canbus, controller area network - G05B 2219/39186: Flexible joint - G05B 2219/40417: For cooperating manipulators - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract Disclosed herein are embodiments related to braking joints in robotic systems. For example, an apparatus for collaborative robotics may include a first segment, a second segment, and a joint assembly. The joint assembly may include a stepper motor to control a relative position of the first and second segments, and a phase of the stepper motor may be shorted when the apparatus is unpowered. ## Claims ### Claim 1 An apparatus for collaborative robotics, comprising: a first segment; a second segment; and a joint assembly, wherein the joint assembly includes a stepper motor to control a relative position of the first and second segments, and a switch to selectively short a phase of the stepper motor. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the joint assembly further includes a drivetrain, and the drivetrain has a gear ratio that is less than 30:1. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the switch includes a mechanical relay to short the phase. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the switch includes a solid state relay to short the phase. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the switch includes an H-bridge to short the phase. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the apparatus does not include a mechanical brake to brake the joint assembly. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein, when the switch is configured to short the phase of the stepper motor, a braking force of the joint assembly may be overcome by typical human force. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the joint assembly is one of a plurality of joint assemblies of the apparatus, and individual ones of the joint assemblies include a stepper motor and a switch to selectively short a phase of the individual stepper motor, and different ones of the joint assemblies are communicatively coupled by a Universal Serial Bus (USB) link, a Controller Area Network (CAN) link, or an RS-485 link. ### Claim 9 An apparatus for use in a robotic system, comprising: a processing device to: identify a signal to brake a joint assembly, wherein the joint assembly is driven by a stepper motor, and in response to identification of the signal, cause a phase of the stepper motor to be shorted. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the signal is generated in response to a fault condition. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein the signal is generated in response to a command to turn brakes on. ### Claim 12 (depends on 9) The apparatus of claim 9, wherein the signal is generated in response to a command to turn motor drive off. ### Claim 13 (depends on 9) The apparatus of claim 9, wherein the processing device is part of the joint assembly. ### Claim 14 (depends on 9) The apparatus of claim 9, wherein the signal is a first signal, and the processing device is to: identify a second signal to stop braking the joint assembly; and in response to identification of the second signal, cause the phase to no longer be shorted. ### Claim 15 (depends on 9) The apparatus of claim 9, wherein the processing device is a first processing device, and the first processing device is to: receive the signal from a second processing device in communication with the first processing device via a communications bus. ### Claim 16 An apparatus for use in a robotic system, comprising: a processing device to: cause a phase of a stepper motor to be shorted to brake the stepper motor, and cause the phase of the stepper motor to not be shorted together to allow the stepper motor to move. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein a gear ratio of a drivetrain of the stepper motor is less than 30:1. ### Claim 18 (depends on 16) The apparatus of claim 16, wherein the stepper motor is part of a robotic arm. ### Claim 19 (depends on 16) The apparatus of claim 16, wherein the stepper motor is part of a robotic gantry. ### Claim 20 (depends on 16) The apparatus of claim 16, wherein the robotic system is a product inspection system.