Technique for selecting a transmission mode for wirelessly transmitting a message comprising control information for robotic device control
An apparatus for selecting a transmission mode for wirelessly transmitting a message comprising control information for robotic device control is provided. The apparatus is configured to compare a current message with a previous message to identify a change in the control information, and to select one of a normal transmission mode and a robust transmission mode, wherein the robust transmission mode is selected if a change in the control information is identified. In another variant, the apparatus is configured to obtain a count of consecutively not correctly received messages, and to select one of a normal transmission mode and a robust transmission mode based on the obtained count, wherein the robust transmission mode is selected if the count equals or approaches a threshold. The apparatus is also configured to trigger wireless transmission of the current message with the selected transmission mode.
1 . An apparatus for selecting a transmission mode for wirelessly transmitting a message comprising control information for robotic device control, the apparatus comprising:
a processor; and
a memory coupled to the processor, wherein the memory stores one or more programs that, when executed by the processor, cause the apparatus to:
compare a current message, which is to be transmitted after a previous message, with the previous message to identify a change in the control information from the previous message to the current message;
select one of a normal transmission mode and a robust transmission mode which is more robust than the normal transmission mode for wireless transmission of the current message, wherein the apparatus is configured to select the robust transmission mode if a change in the control information is identified; and
trigger wireless transmission of the current message with the selected transmission mode.
2 . The apparatus of claim 1 , wherein correct receipt of the previous message has been acknowledged.
3 . The apparatus of claim 1 , wherein the one or more programs, when executed by the processor, cause the apparatus to compare the current message with the previous message by performing at least the following steps:
obtaining at least one part of the control information comprised in the current message;
obtaining at least one part of the control information comprised in the previous message; and
comparing the at least one part of the control information comprised in the current message with the at least one part of the control information comprised in the previous message.
4 . The apparatus of claim 3 , wherein the one or more programs, when executed by the processor, cause the apparatus to obtain the at least one part of the control information comprised in the current message by performing at least the following steps:
masking at least one part of the current message to define at least one masked part and at least one unmasked part of the current message; and
extracting the at least one unmasked part of the current message as the at least one part of the control information comprised in the current message.
5 . The apparatus of claim 4 , wherein the one or more programs, when executed by the processor, cause the apparatus to mask at least one of:
a protocol field comprised in the current message; and
a message part which has no effect on a reaction time of a robotic device to be controlled.
6 . The apparatus of claim 4 , wherein the one or more programs, when executed by the processor, cause the apparatus to:
apply a plurality of different masks to define at least one masked part and at least one unmasked part for each of the different masks, wherein each one of the plurality of masks has an associated priority level; and
extract the at least one unmasked part as the at least one part of the control information separately for each one of the plurality of masks.
7 . The apparatus of claim 6 , wherein the one or more programs, when executed by the processor, cause the apparatus to:
compare the at least one unmasked part of the control information comprised in the current message with the at least one unmasked part of the control information comprised in the previous message, for each one of the plurality of masks, to identify a change in the control information from the previous message to the current message;
determine one of the plurality of masks associated with the change in the control information; and
select the robust transmission mode based on the priority level associated with the determined mask.
8 . The apparatus of claim 7 , wherein the one or more programs, when executed by the processor, cause the apparatus to determine one of the plurality of masks based on which a change in the control information from the previous message to the current message is identified.
9 . The apparatus of claim 3 , wherein the one or more programs, when executed by the processor, cause the apparatus to obtain the at least one part of the control information comprised in the previous message by performing at least the following steps:
masking at least one part of the previous message to define at least one masked part and at least one unmasked part of the previous message;
extracting the at least one unmasked part of the previous message as the at least one part of the control information comprised in the previous message.
10 . The apparatus of claim 3 , wherein the one or more programs, when executed by the processor, cause the apparatus to compare the current message with the previous message by performing at least the following steps:
obtaining a first hash of the at least one part of the control information comprised in the current message;
obtaining a second hash of the at least one part of the control information comprised in the previous message; and
comparing the first hash with the second hash.
11 . The apparatus of claim 10 , wherein the one or more programs, when executed by the processor, cause the apparatus to identify a change in the control information from the previous message to the current message based on a result of comparing the first hash with the second hash.
12 . The apparatus of claim 11 , wherein the one or more programs, when executed by the processor, cause the apparatus to identify a change in the control information from the previous message to the current message in case the first hash is not equal to the second hash.
13 . The apparatus of claim 1 , wherein the robust transmission mode comprises at least one of:
transmitting the current message more often than with the normal transmission mode; and
transmitting the current message using a modulation scheme which is more robust than a modulation scheme of the normal transmission mode.
14 . The apparatus of claim 1 , configured to be connected to the robotic device via a fieldbus connection.
15 . The apparatus of claim 1 , configured to be connected to a controller via a fieldbus connection.
16 . A system comprising:
a robotic device; and
an apparatus for selecting a transmission mode for wirelessly transmitting a message comprising control information for robotic device control, wherein at least a portion of a communication link between the apparatus and the robotic device is a fieldbus connection, wherein the apparatus is configured to:
compare a current message, which is to be transmitted after a previous message, with the previous message to identify a change in the control information from the previous message to the current message;
select one of a normal transmission mode and a robust transmission mode which is more robust than the normal transmission mode for wireless transmission of the current message, wherein the apparatus is configured to select the robust transmission mode if a change in the control information is identified; and
trigger wireless transmission of the current message with the selected transmission mode.
17 . The system of claim 16 , wherein the robotic device comprises a robot controller configured to:
control the robotic device based on control information comprised in a message received by the apparatus.
18 . The system of claim 16 , wherein the robotic device comprises a robot controller configured to generate the current message or the message comprising the control information based on a current state of the robotic device.
19 . The system of claim 16 , further comprising a controller, wherein at least a portion of a communication link between the apparatus and controller is a fieldbus connection.
20 . The system of claim 19 , wherein the controller is configured to determine desired control information based on control information comprised in a message received by the apparatus.
21 . The system of claim 19 , wherein the controller is configured to generate the current message or the message comprising the control information.