The KeiganMotor electric motor employs Nordic’s nRF52832 SoC enabling users to wirelessly program and control robotic applications via partner app
Nordic Semiconductor recently announces that Keigan Inc., a Kyoto, Japan-based robotics and motor systems manufacturer, is employing Nordic’s nRF52832 Bluetooth Low Energy (Bluetooth LE) System-on-Chip (SoC) to provide the wireless connectivity for its KeiganMotor. The motor is a brushless, gearless electric unit designed primarily for rapid prototyping of robotic systems in hobbyist, research and development, and automotive applications. The motor can be used within five minutes of unboxing by plugging into the battery and using a smartphone-based partner app.
KeiganMotor features a high-performance brushless DC servo motor, a motor driver, rotary encoder, and a 6-axis accelerometer-gyro sensor, delivering a maximum torque of 0.3Nm with a power consumption of less than 12W. Each motor is powered by an external 5V battery, via a USB Type-C cable. The motor integrates Taiyo Yuden’s "EYSHCNZWZ" Bluetooth LE module — employing Nordic’s nRF52832 SoC — to provide wireless connectivity to a range of Bluetooth 4.0 (and later) compatible devices including iOS and Android smartphones and tablets, PCs, Raspberry Pi, as well as the Nordic-powered micro:bit programmable computer, designed to teach children coding skills.
The company has developed two partner apps, KeiganCore and KeiganPlay. KeiganCore allows the user to not only control one or more KeiganMotors from their smartphone or tablet, but also assign robotic functions to them. KeiganPlay meanwhile is a simple control app, enabling motion control (velocity, position, and torque) via a graphical user interface with positional accuracy within 0.05°. Thanks to the Bluetooth LE wireless connectivity provided by the Nordic SoC, two or more motors can be linked together, enabling them to be cooperatively controlled to execute more complex robotic functions simultaneously.
In the absence of a smartphone, the motor’s on-board absolute encoder allows it to be programmed directly by ‘teaching’ required movements by hand. Each movement’s related motor angles are recorded in the nRF52832 SoC’s Flash memory for later recall and execution. A Software Development Kit (SDK) is available to program the motor for a more complex sequence of movements. In addition to supervising the wireless connectivity, the nRF52832 SoC’s powerful 64MHz, 32-bit Arm Cortex M4F processor (together with the SoC’s independent pulse width modulators (PWMs)) is used to implement Field Oriented Control (FOC), an advanced brushless motor control technique, without the need for an external processor.
Nordic’s nRF52832 multiprotocol SoC combines the Arm processor with a 2.4GHz multiprotocol radio (supporting Bluetooth 5, ANT™, and proprietary 2.4GHz RF protocol software) featuring -96-dB RX sensitivity, with 512kB Flash memory and 64kB RAM. The nRF52832 is supplied with Nordic’s S132 SoftDevice, a Bluetooth 5-certifed RF software protocol stack for building advanced Bluetooth LE applications. Nordic’s unique software architecture provides a clear separation between the RF protocol software and Keigan Inc.’s application code, simplifying the development and testing process and ensuring the SoftDevice doesn’t become corrupted when developing, compiling, testing, and verifying application code. The S132 SoftDevice features Central, Peripheral, Broadcaster and Observer Bluetooth LE roles, supports up to twenty connections, and enables concurrent role operation.
“We selected the Taiyo Yuden module because of the robust Bluetooth LE connectivity of the Nordic SoC,” says Takashi Tokuda, CEO at Keigan Inc. “The performance of the Arm processor and Nordic’s easy-to-use software development kit (SDK) were also important in our decision-making process.
“Also the fast response from engineers to our technical questions on Nordic’s DevZone was wonderful.”