Hubo KHR3 Mini Rig Tutorial:
The objective of this tutorial is to show how to setup the main computer of Hubo KHR3 to the CAN bus which is also connected to one or more motor drivers and IMUs. In this tutorial there will be connecting one (1) Main Computer, one (1) Motor Driver, and one (1) IMU together.
- Main Computer PCM-3370 with CAN Bus card PCM-6380
- Motor Controller/Driver
- ATX Power Supply
- 48VDC Power Supply
- 12VDC Power Supply
- CAN Bus Junction with 1.21k ohm resistor
See Figure 1 for a picture of all of the parts listed above hooked up together.
Figure 1: Setup for the Hubo KHR3 Mini Rig
The Main Computer consists of three major parts.
- Main Computer PCM-3370
- CAN Bus Card PCM-3680
- IDE Hard Drive
The Hard Drive and the CAN Bus card are both hooked up to the Main Computer via an IDE and PC-104 connection respectively, see Figure 2.
Figure 2: Setup of Main Computer with CAN Bus card and Hard Drive
The Main Computer is powered by the ATX power supply, as seen in Figure 1, but through an AT connector cable. The Main Computer requires both a 5V and a 12V input. Please see Figure 3 for the location of the converted ATX to AT power supply connector attached to the Main Computer.
Figure 3: Main Computer with CAN Bus card and AT Power Supply attached
Due to the fact that ATX power supplies are ‘soft on’ devices we need to jumper the ‘on’ pins on the ATX connector head in order for the power supply to always be in the ‘on’ state and thus work as an AT power supply with the proper cable converter. Please see Figure 4 for the ATX header being jumpered in the correct place for the power supply to always be in the ‘on’ state.
Figure 4: ATX Power Supply header with ‘on’ pins jumpered to keep state of always in the ‘on’ state
The Main Computer setup is hooked up to the CAN Bus via the pins furthest to the right on the CAN Bus card, see Figure 5.
Figure 5: CAN Bus card on the Main Computer hooked up to the CAN Bus via the yellow and black CAN Bus cable
The CAN Bus cable is then hooked up to the CAN Bus Junction. This junction has a 1.21k ohm resistor between the signal and ground. This helps with impedance matching. This junction is the junction at which the other devices on the CAN network will connect to allowing them to communicate. See Figure 6 for a picture of the CAN Bus Junction.
Figure 6: CAN Bus Junction with 1.21k ohm resistor between signal and ground.
The order in which each device is connected to the CAN Bus Junction, as seen in Figure 6, is not important because they are all hooked up in parallel. Also note that there is only a single 1.21k ohm resistor across all of the CAN Bus connections NOT one for each.
The CAN Bus is then connected to the Motor Controller, see Figure 7. The Main Computer will send messages to the Motor Controller and will command the Brushless DC motor to do the given command. The Motor Controller/Driver board found in Figure 7 is able to control two brushless DC motors with optical encoder feedback and Hall Effect sensors or each motor. The Motor Controller/Driver requires two separate inputs, one input is 48VDC (high current). This input is to drive the DC Motors. The other input is a 12VDC which is used to power the electronics. Note that in this setup the 48VDC and the 12VDC are coming from the DC power supply from Figure 1. Please see annotations on Figure 7 for the proper locations of each of the device hookups.
Figure 7: CAN Bus Motor Controller/Driver, Duel Brushless DC Motors. Motor A and Motor B. Motor A is hooked up in this figure.
The IMU is also hooked up via the CAN Bus. The Main Computer will send messages to the IMU and it will respond with the proper data. Please see Figure 8 for the setup of the IMU.
Figure 8: IMU Setup
Now that everything is hooked up you can turn on the power supplies. Make sure that the 48VDC power is NOT hooked up to the 12V terminals. After everything is powered up and you have given the computer about a minute (60 sec) to boot up connect to the computer via remote desktop and start working.