IndyDCP3

IndyDCP3 is a remote procedure call (RPC) protocol that utilizes gRPC. It is based on HTTP/2, offering high performance and rapid communication speeds, and features language neutrality, allowing for easy development across various languages. Additionally, it supports bidirectional streaming and asynchronous communication, enabling the implementation of a wide range of applications.

Note

Communication speed may vary depending on the network latency between the client and server, message size, and the system's processing capability. The actual communication speed is determined by the application's requirements and resource limits. For IndyDCP3, the average latency for basic robot state message responses (e.g., receiving joint angles) over a wired network connection is approximately 2ms.

For Python and C++ clients of IndyDCP3, Neuromeka officially provides them, so you can use them directly through the links below. For other development languages, please refer to the rest of the documents in this chapter.

Developing IndyDCP3 Client Using Protobuf

In this chapter, we will explain how to implement IndyDCP3 (gRPC) clients in various development languages using Protobuf.

Protobuf

Protocol Buffers (Protobuf) is Google's language-neutral data format for efficiently serializing structured data. gRPC natively uses Protobuf to exchange data between clients and servers.

Installing Protobuf

You can install the Protobuf compiler (protoc) to compile .proto files. Installation instructions for various operating systems are available on the Protocol Buffers GitHub page.

Defining .proto Files

Define data structures (message) and service interfaces in .proto files.
Messages consist of field types, names, and unique numbers.
Services define RPC methods and their request/response message types.

syntax = "proto3";

package example;

// Message definition
message MyMessage {
  int32 id = 1;
  string name = 2;
  repeated string values = 3;
}

// Service definition
service MyService {
  rpc MyMethod(MyMessage) returns (MyMessage);
}

Compiling .proto Files

Use the protoc compiler to transform .proto files into code for a specific programming language.
Example: protoc --java_out=. my.proto

Implementing a gRPC Client

Implement a gRPC client using the generated code.
The server implements the defined service interface (IndyDCP3 server), and the client sends requests to the server through this interface.

Exchanging Messages

The client sends data to the server using the defined Protobuf message format.
The server receives this data, performs the necessary operations, and returns a response to the client.

Additional Resources

For more detailed information and usage, refer to the Protocol Buffers documentation and the official gRPC documentation.

This manual introduces the basic concepts and procedures for using gRPC and Protobuf. Actual implementation may involve additional steps and considerations specific to each programming language and framework.

Protobuf for IndyDCP3

Below is a summary of some of the protobuf definitions used by IndyDCP3.

Service	RPC Method	Request Message	Response Message	Description
Control	GetControlInfo	Empty	ControlInfo	Retrieves control information of the robot.
	MoveJ	MoveJReq	Response	Moves the robot to a specified position in joint space.
	MoveJT	MoveJTReq	Response	Moves the robot in joint space within a specified time.
	MoveL	MoveLReq	Response	Moves the robot to a specified position in workspace.
	MoveLT	MoveLTReq	Response	Moves the robot in workspace within a specified time.
	MoveC	MoveCReq	Response	Moves the robot in a circular path in workspace.
	MoveCT	MoveCTReq	Response	Moves the robot in a circular path within a specified time.
	WaitIO	WaitIOReq	Response	Waits for a specified I/O signal.
	WaitTime	WaitTimeReq	Response	Waits for a specified time.
	WaitProgress	WaitProgressReq	Response	Waits for progress status.
	WaitTraj	WaitTrajReq	Response	Waits until trajectory movement is complete.
	WaitRadius	WaitRadiusReq	Response	Waits until movement within a specified radius is complete.
	MoveJCond	MoveJCondReq	Response	Moves the robot in joint space conditionally.
	...	...	...	...
Device	SetBrakes	MotorList	Response	Changes the brake settings of motors.
	SetServoAll	State	Response	Sets the state of all servos.
	GetDI	Empty	DigitalList	Retrieves the digital input status.
	GetDO	Empty	DigitalList	Retrieves the digital output status.
	...	...	...	...
RTDataExchange	GetMotionData	Empty	MotionData	Retrieves motion data.
	GetControlData	Empty	ControlData	Retrieves control data.
	...	...	...	...
Config	SetRefFrame	Frame	Response	Sets the reference frame.
	GetHomePosition	Empty	JointPos	Retrieves the home position.
	SetSpeedRatio	Ratio	Response	Sets the speed ratio.
	...	...	...	...

The table briefly summarizes key functionalities, and the complete protobuf file can be downloaded from Neuromeka Github.