Kondo Robot RCB3/H2H3 Versions and Compatibility

There appears to be some confusion recently about the versions and compatibility for the Kondo RCB3 controller and the Heart To Heart 3 (H2H3) software application. Hopefully the history, explanation and chart below will help clear up some of the confusion rather than making it even more confused.

First we should probably make it clear that the following is based on our limited experience and doesn't represent any official position from Kondo. We believe the information to be factually correct, but would definitely welcome any input or corrections if you find any mistakes or oversights.

Kondo Robot Controller History

Kondo's robot controller board "RCB" series started with the RCB1 which was designed for use with the original KHR-1 humanoid robot kit - the first fully functional commercial bipedal robot kit released three years ago. The RCB1 provided basic functionality - basically stop motion movement control along with the ability to capture servo positions  to create complex motion sequences and scenarios. Each RCB1 board could control up to 12 servos, therefore the KHR-1, with 17 DOF, required the use of two RCB1 controllers.

Kondo provided a basic motion creation program called Heart to Heart (H2H) with the RCB1 controller board, and over the course of two years the program went through several release cycles to correct reported bugs. The initial H2H application and user manual was translated in English by a third party (iXs) that also served as an overseas distributor for Kondo products. Some attempt was made to update the translated version with the first set of bug fixes, which corrected some problems but introduced a few new bugs.

As interest in hobby level humanoid robots climbed in Japan, there was a strong demand for increased functionality, including the ability to manage more DOF on the same board, operate at higher voltages, and improved programmability and scripting.  To satisfy that growing market demand, Kondo OEM'd the Motion Processor board design and associated software from Himeji Soft Works.

The new controller, sometimes referred to as the RCB2, proved to be very popular with ROBO-ONE builders including Sugiura Family (Dynamizer, Retro), Dr. GIY (Yokozuna Great), Maru Family (King Kizer) and others. Unfortunately, because of it's relatively high cost and lack of English documentation, sales outside of Japan never took off.

RCB3 History

Based on the success of the KHR-1 humanoid robot kit, and with feedback from a large devoted customer base, Kondo developed the next generation controller board - the RCB3 - and the associated H2H3 software application.

Physically the same size as a single RCB1 board, the RCB3 was designed to support up to 24 DOF with three analog sensor channels and advanced motion creation and programability. An important design criteria was the ability to support a wide range of Kondo servos including the KRS-700 and 4000 series. The new controller was unveiled to the press in the Spring of 2006 and saw its first commercial application as the controller for the KHR-2HV robot kit.

Because the KHR-2HV uses the KRS-700 series servos that do not support advanced serial (ICS) capability, Kondo decided to release the controller as the "RCB3J" - with firmware that doesn't have the serial functionality. It's likely that the "J" in RCB3J stands for "junior", though we can't be sure. The matching software application, H2H3J was released at the same time, and was subsequently translated into English for sales outside of Japan.

At the sametime, Kondo was developing the servo and controller systems for the Kyosho Manoi series of robot kits - the AT01 and PF01, along with the more up-market KHR-1HV robot kit design. Since those new robot designs utilized KRS-4000 series servos that could potentially use the serial capability, Kondo released the RCB3 board with fully implemented firmware.

It's important to note that the H2H3 application and documentation have yet to be translated. It is possible to use the H2H3J English version of the software with robots like the KHR-1HV and Manoi AT01, though that approach is not officially supported and users may run into problems if the servos have been upgraded to the KRS-4013/4014 types that support serial capability.

RCB3 Firmware Upgrade

In February, 2007, immediately preceding the release of the Kyosho MANOI PF01 robot kit, Kondo introduced a new firmware version for the RCB3 that included significant performance enhancements. The new firmware, designated the "RCB V1.03", added improved processing speed, the ability to call and return from motion sequences under program control (effectively enabling the creation of a state machine), and many other useful improvements.

At the same time a new version of the software application, H2H3_070205 was released to take advantage of the new controller firmware. At this time, the new firmware is shipping as a part of the Manoi PF01 kit, and is also sold separately. Kondo also has a promotional program on their website for customers to upgrade their existing RCB3  controllers to the new firmware for a small charge. Of course the boards have to be shipped to Kondo in Japan for the upgrade.

The upgrade does not apply to the RCB3J controller boards (KHR-2HV), and the company has not officially stated if and when an upgraded version of the RCB3J might be made available. 

Compatibility Matrix 

Robot Kit




Manoi AT01

Manoi PF01





  H2H3J English












  RCB3 V1.03












   O = Okay     U = Upgrade possible

In terms of upgrading from the original RCB3 firmware to V1.03, existing motion sequences are compatible, but require some editing to adjust for timing and functional differences between the firmware versions.

It is also possible to upgrade an original KHR-1 robot to use the RCB3 V1.03 controller, as we have reported in a previous post. We upgraded Gulliver, our KHR-1, to the RCB3 V1.03 configuration for several reasons.

First, we really wanted to keep our motion development as simple and easy to manage as possible, so having all of our humanoids using the the same controller was a major factor.

Second, by switching from the RCB1 to the RCB3, we immediately gained access to all the great motion sequences created for use with the KHR-2HV. With minor modifications we can use any of the KHR-2HV motions and scenarios with Gulliver.

Third, the RCB3 provides much higher effective resolution than the RCB1, meaning that we can control servo positioning roughly 3X more accurately, which makes it much easier to establish a reliable home position and much smoother and realistic movements. 

Related links:

Kondo Website (Japanese)


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