Hi all,
I have some custom ROS messages that I have loaded into MATLAB utilizing the rosgenmsg routine. Everything went fine and they show up when calling rosmsg list.
When I went to read messages of the custom type from my rosbag I received the following error:
Reference to non-existent field 'Forces_'.
Error in robotics.ros.custom.msggen.sfm_msgs.Forces/reload (line 165)
Forces_Cell = arrayfun(@(x) feval([obj.SfmMsgsForceClass '.loadobj'], x), strObj.Forces_, 'UniformOutput', false);
Error in robotics.ros.Message/fromStruct (line 172)
obj.reload(sObj);
Error in robotics.ros.BagSelection/readMessages (line 280)
msgs{i}.fromStruct(msgStructs{i});
I did some investigation on how the function works and where the error comes from. In
robotics.ros.Message/fromStruct
the code tries to create a message object from the bag information (which is in struct format). For my custom message of type
the field names for the message and the structs (these are autogenerated by rosgenmsg) differ:
K>> msgs{1}
ans =
ROS Forces message with properties:
MessageType: 'sfm_msgs/Forces'
Header: [1×1 Header]
Forces_: [0×1 Force]
versus
K>> msgStructs{1}
ans =
struct with fields:
MessageType: 'sfm_msgs/Forces'
Header: [1×1 struct]
Forces: [1×6 struct]
This leads to the top-most error of my error message. As mentioned, this naming difference is autogenerated by the rosgenmsg routine.
The original .msg message definitions are:
Forces.msg:
std_msgs/Header header
Force[] forces
Force.msg:
uint8 ATTRACTIVE=0
uint8 INT_ROBOT=1
uint8 INT_OBSTACLE=2
uint8 INT_HUMAN=3
uint8 type
string entity_name
geometry_msgs/Vector3 force
So... yeah. I have no idea how to fix this and as far as I am considered this is a bug in the rosgenmsg routine. Hopefully some of you guru's have an idea!
P.S. I am using MATLAB Version: 9.4.0.813654 (R2018a) with Robotics System Toolbox Version 2.0 (R2018a)
