Tutorial: Building a Simple 2-Bar Robot - Actuator Mapping

Setting up Actuators (Example: Synapticon JD Series)

In the previous section, we completed the modeling of the robot's kinematics and dynamics. Now, we must map this theoretical model to the physical hardware: the Actuators.

This tutorial guides you through mapping your theoretical robot model to physical Synapticon JD8/JD10 actuators. Follow these steps to get your robot running quickly. The goal is to mount a JD10 on Joint 1 and a JD8 on Joint 2.

Step 1: Verify Actuator Nodes

Upon entering the Actuator Mapping page, verify that the actuator and joint nodes have been automatically generated based on your previous robot structure configuration. * Status: Ensure nodes are visible (currently in an Unlinked state).

⚠️ Troubleshooting: Node Count Mismatch If the number of Actuators and Joints does not appear as expected (2 pairs for this tutorial), please return to the Robot Structure tab. * Check Joint Type: Verify that the Joint Type is set to Rotation Z. If set to None, it is not counted as a valid Degree of Freedom (DoF) and will not generate a mapping node.

Screen displaying actuators and joints.

Step 2: Input Motor Specifications

1. Click the [Motor Information] button on the actuator node.
2. Refer to the specifications below and enter the data into the right panel.

Actuator 1 (Joint 1): Synapticon JD10

Parameter	Specification
Product Name	ACTILINK-JD Circulo 10
Rated Torque	2.2222 Nm
Peak Torque	6.6667 Nm
Rated Output Power	380 W
No-Load Speed	1,890 rpm
Rated Load Speed	1,620 rpm

Actuator 2 (Joint 2): Synapticon JD8

Parameter	Specification
Product Name	ACTILINK-JD Circulo 8
Rated Torque	0.774 Nm
Peak Torque	2.194 Nm
Rated Output Power	170 W
No-Load Speed	3,100 rpm
Rated Load Speed	2,131 rpm

Note: Ignore the Gear Ratio field in this step; it will be handled in the Transmission setup (Step 4).

Actuator 1 specs entered (Referencing Synapticon JD10).

Step 3: Configure EtherCAT Communication

Click [EtherCAT Settings] to configure the driver communication.

1. SDO Settings: For Synapticon drives, skip the SDO Entry 1.
   • Note: These drives use a transactional safety model. Perform the Absolute Encoder Reset using the manufacturer's dedicated software instead.
2. PDO Settings: Set the indices for User-Defined Mapping.
   • RxPDO (Master to Driver): Set mapping index to 0x1600. Ensure it maps Control Word, Target Position, etc.
   • TxPDO (Driver to Master): Set mapping index to 0x1A00. Ensure it maps Status Word, Actual Position, etc.

Edit the SDO and RxPDO settings.

Step 4: Configure Transmission (Actuator-Joint Mapping)

Finally, we connect the actuators to the joints. For this 2-Bar robot, we use a simple 1:1 Mapping strategy where each motor drives exactly one joint.

Procedure: 1. Switch the view to Diagram Mode. 2. Click Add Edge to draw connection lines. 3. Connect Actuator 1 to Joint 1. 4. Connect Actuator 2 to Joint 2.

(Insert image of 2 actuators connected to 2 joints here)

Setting the Transmission Values: You must input the reduction ratio (inverse of gear ratio) for each connection.

Important: Do not enter fractions (e.g., 1/9). You must calculate and enter the decimal value.

Connection 1 (JD10 → Joint 1): * The JD10 has a gear ratio of 9 : 1. * Calculation: 1.0 / 9.0 ≈ 0.111111 * Input Value: 0.111111

Connection 2 (JD8 → Joint 2): * The JD8 has a gear ratio of 7.75 : 1. * Calculation: 1.0 / 7.75 ≈ 0.129032 * Input Value: 0.129032

Direction Tip: If a joint rotates in the opposite direction of the command during testing, simply change this value to a negative number (e.g., -0.111111).