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ROBOTIS-GIT / dynamixel-workbench

ROS packages for Dynamixel controllers, msgs, single_manager, toolbox, tutorials
http://emanual.robotis.com/docs/en/software/dynamixel/dynamixel_workbench/
Apache License 2.0
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Unable to Read Motor Shutdown Register #235

Closed adithyamurali closed 5 years ago

adithyamurali commented 5 years ago

Hi everyone, I am using the dynamixel_workbench_controller and SDK to connect to a manipulator arm from Trossen Robotics. The arm is essentially a chain of XM430 and XL430s.

Sometimes the dynamixel motors shuts down (RED LED flickering) so I wanted to understand why they were failing. I tried to read from the Shutdown (63) register with both itemRead and getSyncReadData but I always get the initial value ‘52’ for all the motors (even after the motor shuts down). For syncRead, the control_items address is 63 and data_length is 1 (so I’m assuming I’m reading at the right spot).

I’m not even sure if I’m interpreting the value correctly. Even when the motor is functioning, I’m reading a value of 52 (binary 00110100) means there is a Overheating, Electrical shock and Overload errors, according to the documentation screenshot below?

shutdown

Documentation link: http://support.robotis.com/en/product/actuator/dynamixel_x/xm_series/xm430-w350.htm#bookmark16

Any insights and suggestions would be much appreciated, thanks!

yhna commented 5 years ago

Hello, @adithyamurali The Shutdown(63) register in the control table of dynamixel is an option to shut down dynamixel when an error condition occurs. If dynamixel has been shut down, the Hardware Error Status (70) register indicates the shutdown reason.

adithyamurali commented 5 years ago

Hi @yhna , thanks for the reply! I can now read the Hardware Error Status (70). It seems that when the motors are shutting down I'm seeing a Overload error (error 32, 0x20). I notice that this happens mostly for some motors on the arm (carrying more payload I believe). The motors work fine for several iterations of commanding the same joint positions but shutdown a while later. When I power cycle the motors, they start working again but for a while. Do you have any thoughts on reducing the frequency of these shutdowns (e.g. reducing profile velocity)?

yhna commented 5 years ago

@adithyamurali Since the persistent load exceeds the maximum output of the Dynamixel, it can not be resolved by changing the parameters of Dynamixel. I recommend using a higher specification Dynamixel or reducing the weight of the robot.

adithyamurali commented 5 years ago

Great, thanks for the help!